An Alternate Technique for Total Hip Surgery: The Direct Anterior Approach.

Total hip replacement surgery commonly performed with one of two methods, direct lateral (from the side) or posterior (from the back). In recent years a previously described technique called the Direct Anterior Approach (DAA) has gathered interest because it is a less invasive procedure. This article by Post, et al, is a description of this procedure, indications for it’s use and difficulties commonly seen with this technique.

This procedure was described as long ago as 1881, however with recent improvements in surgical tools and operating tables specifically for the DAA, it has regained popularity. For the DAA a space in the front of the hip, known as the Heuter interval, is utilized to access the hip joint. Using this space allows the surgeon to avoid cutting through muscle or nerves while replacing the hip. This is argued to decrease pain and improve the speed of recovery following a total hip replacement.

Contraindications for DAA included body mass index above forty due to increased abdominal adipose tissue which presents a challenge for this approach. Another consideration is for patients with previous hip surgery as it is not possible to remove plates that are on the side of the hip or femur with this technique.

This procedure does require significant experience from the surgeon, as most studies have found that complication rates decrease after more than one hundred cases. Other small studies have found less pain and better function at six weeks compared to more traditional approach, however there was no difference by six months. A few other retrospecitive studies have demonstrated reduced pain, but it appears that larger randomized studies are needed to determine if there is an advantage to the DAA.

In summary the DAA technique is a viable option, especially with recent improvements in surgical tools for a successful hip replacement. However more long term research needs to be conducted to determine if there is an advantage in long term outcomes. It is also an approach that requires greater surgical experience to avoid common complications, and should be considered when opting for this procedure.

Screw Type for Hip Fracture Correction Effects Cost Outcomes

Hip fractures are a very prevalent (~150,000 annually) and costly (~ six billion dollars annually) problem in the United States.  Because of the high costs associated with the care and recovery from a hip fracture, the type of implants being used are under scrutiny.  Implant type is traditionally determined by the hip fracture.  If the hip fracture is considered “stable” then a screw is attached external to the bone, called an extramedullary sliding hip screw. These show favorable outcomes. An “unstable” hip fracture is often fixed using an intramedullary nailing, which is a rod that is driven into the middle of the bone to help hold the fragments together. These intramedullary nails are more costly than the sliding screws used for a stable hip fracture correction.

Unfortunately, hip fractures are not often straight-forward and the determination of whether the fracture is stable or not and which screw to use is left up to the surgeon. The failure of the screws is foremost on the surgeon’s mind because failure means another surgery and more pain for the patient.  Not unexpectedly, then, when surgeons are faced with the decision of which screw to use with a questionably unstable or stable fracture, they choose the intramedullary nailing screw.

Authors of a recent study were interested if this in fact saved money or if it ended up being a higher bill for the patient. They drew from a large sample of hip surgeries and found that results hinged on the fixation failure rate and the implant cost itself. For a stable hip fracture, the obvious choice of using an extramedullary sliding hip screw proved cost effective.  This also proved cost effective for a questionably stable hip fracture for about 70 per cent of the cases.  They concluded that for stable and questionably stable hip fractures a sliding hip screw is the best choice.

What Is Femoral Head Osteonecrosis and What Are the Treatment Options?

Osteonecrosis of the femoral head most frequently affects 30 to 50 years old, with 20,000-30,000 new cases diagnosed annually. Although the actual pathology behind femoral osteonecrosis is not yet understood, the disease typically follows a progression to eventual femoral collapse, which results in the need for a total hip replacement.

Osteonecrosis literally translates to bone death. There are several reasons why this can occur. Ischemia, or lack of blood flow, is one.  This can happen from trauma (like a hip dislocation or fracture), a blood clot blocking blood flow, or high blood pressure at the level of the bone tissue from excessive alcohol or corticosteroid use.  Some genetic  blood clot formation mutations have also been linked to femoral osteonecrosis. Disruption to the bone cells themselves by irradiation, chemotherapy, or the presence of excessive free radicals, also causes osteonecrosis. Primary risk factors include corticosteroid use, alcoholism, trauma, and coagulation disorders. They have found, however that a risk factor alone does not determine the onset of osteonecrosis, but that there must also be a genetic factor present.

The earlier the disease is diagnosed, the better the outcome. The most frequent symptom is deep groin pain that can radiate to the buttock or knee on the same side. The gold standard for femoral osteonecrosis detection is an MRI, which can give insight into the amount of bone death present, its location, and the amount of swelling in the bone. All of this information can help physicians treat the problem and predict whether or not the femoral head will “collapse,” which then means a need for a total hip replacement.

Nonsurgical treatment of femoral osteonecrosis is limited to smaller, symptom free lesions for a period of no weight bearing to see if symptoms do occur.  Little evidence exists backing shockwaves and electromagnetic field treatment. Pharmacologic agents are also not strongly backed in the literature for prevention and treatment of femoral osteonecrosis.

Surgery is the primary treatment option for femoral head osteonecrosis and consists of femoral head preserving procedures or total hip replacement. The type of femoral head preserving procedure is subject to debate and dependent on the extent and location of the bone death. Femoral head sparing procedures are also indicated for the younger patient.

Effectiveness of Surgery For The Middle-Aged Patient With Hip Pain

A recent review of current evidence found that surgical treatment for hip pain in the middle-aged, active patient population is highly dependent on the type of underlying pathology and condition of the joint.  Decisions regarding type of surgery should be made based on the amount of degeneration, bony deformities present, and the ability to repair the labrum and cartilage damage.

The hip joint is a ball and socket joint that has a labrum, or firm piece of tissue that extends out over the socket and makes a deeper pocket to hug the head of the leg bone (femur).  In addition to the suctioning of the labrum, the joint is surrounded by ligaments, which hold the bones together, and muscles on top of the ligaments, which are responsible for moving the bones.  All of these tissues work in conjunction to allow you to move your leg through space in a controlled manner.  If any of these tissues are disrupted, the direction of forces change across the joint and wear and tear can happen at a faster rate.  Wear and tear, or arthritis, can also occur from repetitive activities and from bony anomalies that occur either on the ball of the femur or on the socket of the hip joint.

Femoralacetabular impingement (FAI), hip pain due to a torn labrum or disrupted articular cartilage, can be caused by a “cam-lesion”, “pincer-lesion”, or combination of the two.  A cam-like lesion is a “speed bump” on the ball of the femur.  A pincer-like lesion is a speed bump of bone deposit on the edge of the socket of the hip joint.  Either of these lesions results in hip pain and early wearing away of the cartilage protecting the joint which ultimately leads to further break down of the hip joint.

Young, active patients with cam or pincer lesions or labral tears are very successfully treated with arthroscopic surgery.  Surgeons are able to make a small incision and remove the extra bone and repair the labrum without disrupting much of the joint.  Older, active patients (30 to 50-somethings) with hip pain also have the same lesions or labral tears but additionally often have joint arthritis.  When hip joints become so arthritic that it interferes with daily life a total hip joint replacement is indicated.  However, a middle-aged active person’s joint arthritis typically does not merit total hip replacement but still requires surgical help.

The surgery that results in very good outcomes for the younger population does not give the same results to the middle-aged population.  As many as 25 per cent of the middle-aged hip pain person undergoing the same surgery continue to have hip pain with an increased risk of quick progression to a total hip replacement.

After reviewing the available evidence, authors found people undergoing hip arthroscopic surgery with a decent amount of cartilage damage did not have good pain relief and actually seemed to have an accelerated road towards total hip replacement. Additionally, x-rays do not seem to be a good indicator for estimating how much cartilage damage there is. Authors do point out, however, that the studies reviewed are not ranked highly on the hierarchy of evidence, are a little old in that they mostly only address labral issues, and are not focused on long term outcomes.

Studies that compared labral repairs versus debridement (or removing the extra bony deposits) found that fixing the labrum, even with coexisting cartilage damage (or early arthritis), could possibly prevent or slow down the arthritis.  Furthermore, by fixing the labrum the normal joint mobility and tracking is maintained which can also help slow down the joint degeneration by keeping the joint surfaces rolling and gliding as they should and the labral suction seal intact.

Even though the evidence is lacking for the middle age, active patient with hip pain, the general consensus is that the joint is treated in its entirety by repairing the torn tissues and removing the extra bony deposits that potentially caused the tear in the first place.  Given time, the research should reflect the current surgical practices that are proving to be effective in this population.

Preventing and Treating Leg Length Differences with Total Hip Replacement

Many people don’t realize it, but one of their legs is longer (or shorter) than the other one. Over time, this can lead to degenerative osteoarthritis (OA) in the hip joint requiring a hip replacement. But the surgeon can’t just take the old hip joint out and put the new implant in. Careful planning, special surgical techniques, and adjusting of the implant component parts are important in preventing continuation or even worsening of the leg length discrepancy.

In this article, orthopedic surgeons from Ohio State University offer their perspective and experience treating patients with a limb-length discrepancy. They define and categorize limb-length discrepancy and outline a plan-of-care that takes into consideration preoperative, intraoperative (during surgery), and post-operative evaluation of this problem.

Some limb-length differences are caused by actual anatomic differences from one side to the other (referred to as structural causes). The femur (thigh bone) is longer (or shorter) or the cartilage between the femur and tibia (lower leg bone) is thicker (or thinner) on one side. There could be actual deformities in one femur or hip joint contributing to leg length differences from side-to-side. Even a small structural difference can amount to significant changes in the anatomy of the limb.

A past history of leg fracture, developmental hip dysplasia, slipped capital femoral epiphysis (SCFE), short neck of the femur, or coxa vara (twist of the femur) can also lead to placement of the femoral head in the hip socket that is offset (off-center). The end-result can be a limb-length difference and early degenerative arthritis of the hip.

In other people, there are functional (rather than structural) reasons for the limb-length difference. Shortening or tightening of the soft tissues around the hip on one side can pull the pelvis or femur out of the proper alignment. Weight-bearing through the hip becomes uneven. Uneven compressive forces on the joint wear down the surface causing the degenerative changes associated with osteoarthritis.

Postural asymmetry of the legs can also occur as a result of changes in the lower leg. Stiffness and long-term loss of motion of the knee or ankle for any reason (muscle tightness or contractures, foot deformities) are examples of functional limb-length differences from postural asymmetry.

The body is often very good at compensating for off center alignment (asymmetries). Shifts and changes occur throughout the shoulders, trunk, pelvis, hips and legs to keep the head centered over the spine. But sometimes there are structural, functional, and/or a combination of both types of changes that make the leg length difference worse instead of better. The structures become rigid — no longer able to be corrected with a change in position or after a program of stretching exercises.

When surgery (total hip replacement) becomes the treatment of choice, the surgeon must evaluate any and all contributing factors, including functional and structural causes of leg length differences. Special X-rays (teleoroentgenography, scanography) and more advanced imaging studies (CT scans) are taken preoperatively.

Careful review of imaging studies provides the surgeon with an appreciation of significant issues (e.g., femoral neck shortening or lengthening, a large femoral offset, excessive coxa vara). The authors point out that trying to lengthen or shorten the leg to correct deformities is not advised. The risk of nerve injury and creating an unstable hip is too great.

Replacing the hip joint will not change problems lower down in the knee or ankle or higher up in the spine. Patients must be made aware of what the hip replacement can and cannot do. Even with surgical release of tight soft tissues around the hip, correction of limb-length differences can’t be predicted or guaranteed.

In fact, it is possible that total hip replacement can actually result in major limb-length differences. As the authors point out, through careful evaluation and planning, surgeons make every effort to prevent this from happening. Educational articles like this one aid in reviewing current concepts and guide surgeons through the process.

Measuring offsets, intraoperative assessment of limb length, selecting the best implant for each patient, specifics of surgical techniques, and postoperative care are additional areas of discussion in this article. The authors provide surgeons with many practical considerations when dealing with limb-length discrepancy in patients with osteoarthritis, especially those individuals planning to have a hip replacement.

Hip Osteoarthritis: More Common Than You Think

Consider these statistics: 202,500 total hip replacements were done in 2003. In that same year, 36,000 total hip replacements were operated on again to revise, remove, or replace the first implant. The number of between the ages of 30 and 65 who will develop osteoarthritis is expected to increase two to 10 times the current rate.

With the rising problem of obesity in the United States and the aging population, it is predicted that these figures will increase. For example, it is estimated that by the year 2030, the number of primary (first) hip replacements will increase by 174 per cent. And the number of revision procedures will double in number.

We have always known that hip osteoarthritis is a common problem and one that can be very disabling. But the pace at which the need for hip replacement is rising has taken the orthopedic community by surprise. All previous estimates of future numbers of primary and revision total hip replacements have been way under par.

How do we know the number of cases of total hip replacement has exceeded the projected estimates? Hospitals keep data that is logged into a national data base. Hospital administrators use this information to plan ahead for future needs (e.g., personnel, supplies, facilities) based on current trends.

Not only are more adults being affected by osteoarthritis resulting in hip degeneration, but the age at which the need (the demand!) has occurred has declined. In other words, more and more younger adults (younger than 55 years old) are getting total hip replacements. And that trend is expected to continue into the future as well.

The cost of these procedures is not small. There are direct medical costs (e.g., doctor visits, the surgery, the hospital bill) but also indirect costs. Indirect medical costs refer to lost wages, decreased productivity, and time spent in doctor offices. The cost of care from complementary and/or alternative care must be factored in too. This could include supplements, acupuncture, massages, and energy medicine (e.g., Reiki, BodyTalk, Therapeutic Touch, Touch for Healing).

Finally, there are intangible effects and “costs” of hip osteoarthritis. The effects of pain, loss of motion, reduced function, and decreased quality of life have been measured. For example, researchers have asked patients how many years of life they would give up in exchange for a “cure” of their hip problems. Other studies have assessed the value people place on their health and willingness to pay the cost of a hip replacement.

Not surprisingly, patients who have to pay out-of-pocket (insurance does not cover the cost of the joint replacement) are less likely to give up years of life or money to be free of their symptoms. Whether or not patients heading toward a life of hip pain and loss of function will be willing to take measures to avoid a hip replacement remains unknown.

With the trend toward increasing numbers of people with hip osteoarthritis severe enough to need (or want) an expensive hip replacement surgery, this type of social research will be important. Long-term results of hip replacement (including improvements in quality of life) at all ages will eventually be available.

Those outcomes may further confirm the need for early prevention and willingness on the part of Americans. This will especially be true for those individuals who have a condition known as femoroacetabular impingement (FAI). The shape of their hip from birth puts them at increased risk for degenerative disease later in life. With proper weight management and appropriate exercise this upward trend of osteoarthritis (with or without the impingement problem) may be slowed or possibly even halted. Time will tell.

What is Femoroacetabular Impingement and Does It Really Lead to Hip Osteoarthritis?

Many articles have been written about the condition affecting the hip known as femoroacetabular impingement (FAI). But the current definition is not specific enough to be used when planning clinical trials.

Therefore, the orthopedic surgeons at The Children’s Hospital of Philadelphia (CHOP) have taken on the task of defining this condition with clinical trials in mind. Secondly, they reviewed what is known about the relationship between femoroacetabular impingement (FAI), the later development of hip osteoarthritis, and the eventual need for a hip replacement.

Simply stated, femoroacetabular impingement (FAI) refers to some portion of the soft tissue around the hip socket getting pinched or compressed. Femoroacetabular tells us the impingement is occurring where the femur (thigh bone) meets the acetabulum (hip socket).

There are several different types of impingement. They differ slightly depending on what gets pinched and where the impingement occurs. Anatomic abnormalities of the femur and/or the acetabulum predispose the person to damage of the soft tissue structures inside the joint. Vigorous, repetitive hip motion creates abnormal contact and collision that result in hip pain.

The pain comes on slowly at first. Sitting for long periods of time (prolonged hip flexion) really aggravates the situation. The affected individual may lose hip motion (especially hip flexion and internal rotation). An X-ray will show the changes in the hip typically associated with femoroacetabular impingement (FAI).

The authors propose that in order to include someone in a clinical trial studying femoroacetabular impingement (FAI), there should be three elements consistently present in all participants. These are: 1) symptoms of FAI, 2) positive hip impingement test pain with hip flexion and internal rotation), and 3) imaging findings seen with FAI (e.g., increased alpha angle, bone cysts from impingement, increased lateral center-edge angle).

What about FAI and osteoarthritis? Is there a connection? Well, yes and no. Yes, because people with FAI very often develop osteoarthritis but no because not everyone with FAI develops osteoarthritis and not everyone with osteoarthritis has FAI. The next question that comes up is: which came first? The osteoarthritis and then the FAI or the FAI and then the osteoarthritis? The answer to this question is difficult to determine because osteoarthritis can reshape the bones looking much like femoroacetabular impingement.

The best way to find out is to study young people and follow them through time. X-rays of their hips taken early on can help identify the subset of participants in studies who do, indeed, have FAI. Comparisons can be made over time between those with FAI and those without. Long-term studies can sort out who develops osteoarthritis and what the potential risk factors might be (including FAI).

What has been reported in studies so far? It looks like one particular impingement type (called cam-type impingement) is more likely to lead to tears of the labrum (fibrous rim of cartilage around the hip socket). The cam-type of impingement occurs when the round head of the femur isn’t as round as it should be. It’s more of a pistol grip shape. It’s even referred to as a pistol grip deformity. The femoral head isn’t round enough on one side (and it’s too round on the other side) to move properly inside the socket.

There is some new evidence that the cam-type impingement is the result of participation in high-impact sports. Adolescents (teens) develop this condition as the bones mature. In other words, they aren’t born this way. It appears as though the repetitive motion of the sports activity reshapes the hip resulting in a femoroacetabular impingement (FAI).

Several studies reviewed by the authors present information showing that cam-type deformities are linked with osteoarthritis. But people with cam-type deformities and osteoarthritis are not more likely to end up with a total hip replacement than people without this type of femoroacetabular impingement.

The goal of future studies is to find out who is at risk for developing femoroacetabular impingement that will lead to osteoarthritis and hip replacement. Finding ways to prevent femoroacetabular impingement (and osteoarthritis) would be a natural outcome of these findings. It is possible that risk factors for those who develop osteoarthritis early in life are different than risk factors for adults who develop osteoarthritis in mid- to late-life. This must be investigated as well.

The authors suggest long-term studies should be done following young people through the years. This type of study will give some insight into the natural history (what happens over time) with femoroacetabular impingement (FAI) and osteoarthritis. Variables such as genetic influences, activity levels, and types and severity of anatomic abnormalities should be looked at closely for their role in developing significant FAI and osteoarthritis.

Femoroacetabular Impingement: Diagnosis By Exclusion

Femoroacetabular impingement, otherwise known as FAI, does not have one symptom or one clinical test that tells the physician, “Yes, this person has femoroacetabular impingement FAI)”. Instead, the diagnosis is one of exclusion based on patient history, clinical symptoms, physical examination, and the results of imaging studies (X-rays, MRIs).

We say the diagnosis is one of exclusion because there are other hip problems with similar presentation. The examining physician formulates the diagnosis by excluding other potential causes in order to make the final determination that the condition responsible for the patient’s symptoms is, indeed, FAI.

In this article, orthopedic surgeons from three well-known and well-respected medical centers (Washington University – St. Louis, Mayo Clinic, and Harvard Medical School) teamed up to review the clinical diagnosis of FAI. They provide a description and discussion of the three components needed to make the differential diagnosis.

Beginning with patient history and going through a step-by-step physical examination, they also included imaging studies and say that all three must be reviewed together. Only with the combination of these three factors can the final diagnosis be made with certainty.

What is it about the patient history that tips the physician off that this might be FAI? Here’s where the “exclusion” piece comes in. Because patients with hip pain have a variety of symptoms, questions must be asked to help determine the cause of those symptoms. Was there an accident or injury affecting the hip? Did the person have any hip problems as a child (e.g., slipped capital epiphysis or Legg-Calve-Perthes disease)? Were there any previous surgeries on the hip?

Activity level (especially activities that involve repetitive hip motion) is a key risk factor for FAI, whereas a history of alcohol and steroid use might point more toward something like osteonecrosis (death of bone cells). Labral tears (the labrum is a fibrous rim of cartilage around the hip socket) can cause similar symptoms to FAI (e.g., painful clicking, popping, snapping with hip motion) but is usually associated with a specific injury (often sports-related).

During the physical assessment, the examiner uses different tests to determine whether the pain (or other symptoms) is intra-articular (coming from inside the hip joint) or extra-articular (structures around the joint but not inside the joint). Observing how the patient sits, stands, and walks might provide some additional helpful diagnostic clues. For example, there is a tendency among patients with FAI to sit with a slouched posture to take pressure off the hip.

Limited hip internal rotation is a red flag for FAI. But most other positive findings (e.g., positive FABER test, activities that aggravate or relief pain, positive Trendelenburg sign) only point to the hip as the source of the symptoms, not the actual cause. Likewise, a positive response to injection of an anesthetic (numbing) agent into the hip can confirm the source of pain. Relief of pain with injection directly into the joint confirms the hip (not lumbar spine or groin) as the true origin of pain. These additional areas where pain can occur with FAI cause some diagnostic confusion.

That’s when the physician turns to imaging studies to get a look inside the hip and see what’s going on. Change in the lateral center-edge and alpha angles as measured on X-rays with no sign of hip dysplasia is diagnostic of deformity associated with FAI. On the other hand, MRI-evidence of labral or other cartilage damage helps rule out FAI as the potential source of symptoms.

The authors conclude that since there is no one test, symptom, or clinical finding that confirms a diagnosis of femoroacetabular impingement (FAI), a thorough evaluation is required. With patience and persistence, the orthopedic surgeon can sort through important points in the patient history. Combining that information with findings from the physical examination and imaging studies will be necessary to make the final diagnosis. The differential diagnosis is often one of exclusion through a process or “ruling out” other hip conditions, one at a time.

In-Depth Review of Arthroscopic Hip Surgery

When can and should arthroscopic surgery be done for hip disorders? In this in-depth review of arthroscopic hip surgery, orthopedic surgeons from Northwestern University in Chicago, Illinois offer their insights, opinions, and recent research evidence for treatment decisions regarding a variety of hip problems.

Anyone with hip pain that doesn’t go away with a little stretching, movement, or change in position will need a thorough, systematic patient history and physical examination. Posture, walking pattern, hip range-of-motion, and strength will be evaluated. Special tests to look for specific problems (e.g., labral tears, femoroacetabular or psoas impingement, muscle tightness, instability, bursitis).

Imaging studies such as X-rays will be used to rule out bone fractures and/or detect joint changes due to arthritic degenerative disease. For each of these potential problems, the authors provide a detailed discussion of who is at greatest risk, what the clinical presentation might be, and the choices for surgical management when conservative (nonoperative) care is not successful.

Tables outlining views taken on X-rays and MRIs provide the surgeon with an idea of what to evaluate, what is considered normal versus abnormal, and signs of bony abnormality. Important factors to assess when viewing X-rays when evaluating patients with femoroacetabular impingement (FAI) are also presented in a special table. X-ray examples are included to give a visual understanding of this condition.

Once an accurate diagnosis has been made, then the decision-making process begins in planning the most appropriate and effective treatment. The authors confine their discussion to problems that require arthroscopic hip surgery.

This can include painful labral tears, femoroacetabular impingement (FAI), loose bodies in the joint (e.g., fragment of bone or cartilage), ruptured ligaments, psoas impingement, and snapping hip syndrome. Every effort is made to look for (and find!) secondary or associated injuries that might be present along with the primary condition. This could affect tendon, ligaments, bone, or joint capsule.

Details of patient position during surgery, location of portals (area where arthroscope is inserted into the skin and through the soft tissue to the joint), and surgical technique are provided for each of the conditions mentioned. Once again, the authors provide drawings and patient photos taken during surgery to show exactly what they are describing.

Postoperative rehabilitation, possible complications, and outcomes from long-term studies and systematic reviews make up the final one-third of the article. Now that minimally invasive arthroscopic techniques and tools are available, more and more hip reconstructive surgeries can be done this way. When patients are carefully selected (taking age and severity of the problem into consideration), results are good to excellent with very low complication rates.

Rare But Devastating Complication of Total Hip Replacement

In one-third of one percent (0.32%) of the total hip patients in this study from Thomas Jefferson University Hospital in Philadelphia, Pennsylvania, a serious nerve problem developed. The peroneal nerve (a branch of the much larger sciatic nerve) was pinched, pressed, cut, deprived of oxygen, or exposed to high heat. The result was muscle weakness, loss of normal motor function (movement), and altered sensation.

The large sciatic nerve splits just above the knee to form the tibial nerve and the common peroneal nerve. These two nerves travel to the lower leg and foot, supplying sensation and muscle control. The tibial nerve continues down the back of the leg while the common peroneal nerve travels around the outside of the knee and down the front of the leg to the foot. Either one of these nerves can be damaged by injuries around the knee.

Although this problem only affected a very small portion of the entire patient group (31 of the 9,570 patients), the effects were devastating. Studies like this one may help identify the cause(s) of this rare, but serious complication. The hope is to use this information to help keep them from affecting others in the future.

By taking a look at all the patient characteristics of the 31 patients and comparing them to the rest of the (much larger) group, the authors were able to see one risk factor predicting peroneal nerve palsy. Younger age (less than 56 years old) increased the risk of nerve palsy and poor or slow recovery.

They also saw one prognostic factor (i.e., able to predict when peroneal nerve palsy is more likely to happen). Being significantly overweight (obese) influences recovery in a negative way. In other words, a larger body-mass index (BMI) is a red flag for potential nerve problems associated with total hip replacement.

Some of the patients (40 per cent) who developed nerve palsy showed signs of this emerging problem in the first day after surgery. Most of the rest of the group were diagnosed on the second day after surgery. A few others developed significant nerve palsy sometime during that first week after the procedure (from day three up to day seven).

Despite CT scans and MRIs, the exact cause of the peroneal palsy was not always known. Some of the reasons why patients developed this type of nerve palsy included compression from a hematoma (pocket of blood), lipoma (benign fat tumor), and screw used in the hip replacement (pressing against the nerve).

There were quite a few cases from traction (pulling) on the nerve either directly or indirectly from the use of a surgical tool known as a retractor. In a smaller number of patients, hip dislocation or limb lengthening contributed to nerve damage leading to nerve palsy. And one patient developed nerve palsy from being in a position that put pressure on the lower leg bone (fibula), which in turn, pressed against the nerve.

Time to recovery ranged from one month up to 50 months (four years, two months). Time in the operating room and amount of blood loss did not seem to be significant factors in recovery time. Body size/weight was the main determining factor in whether or not there was full recovery (not whether it was complete or incomplete at the time of the injury).

This study was unable to identify a single body mass index (BMI) threshold (the number at which a nerve palsy is likely to develop). There was a trend observed: the higher the BMI, the greater the chance for incomplete recovery. The lower the BMI, the more likely the patient was to experience full sensory and motor recovery.

In the end, only slightly more than half (57 per cent) of the patients with a peroneal nerve palsy recovered fully after their total hip replacement. In general, it seems to take about a year for patients to regain as much of the lost sensory and/or motor function as possible. In some cases, this time period was extended to 18 months (one and a half years). Preventing this problem may depend on weight loss before surgery. Other preventive measures involve avoiding pressure on or stretch of the nerve from surgical technique or patient positioning.

Bone Loss: Major Obstacle to Hip Replacement Revision

Hip Joint replacements are becoming common place these days. Last year, there were 300,000 total hip arthroplasty (THA) procedures done in the United States. Younger, more active patients are getting their hips replaced. And that means an anticipated higher number of revision (re-do or second) surgeries. Surgeons planning a second or revision surgery after the first total hip replacement must consider many factors. The biggest and most important one is bone loss.

But before we explore the ways around this problem, let’s look at the reasons primary (first or original) hip replacements fail. There are four major reasons for implant failure that require revision surgery: 1) aseptic (without infection) loosening, 2) hip instability (partial or complete dislocation), 3) osteolysis (bone loss) around the implant, and 4) periprosthetic (around the implant) infection.

As you can see from the list, bone loss is a big problem that must be addressed whenever a second surgery is planned. In fact, it’s not just bone loss but also bone quality or density (called bone stock) that must be considered. And there are different patterns of bone loss from patient to patient. So, it’s never a one-surgery-fits-all kind of problem.

Each patient must be carefully evaluated before surgery (pre-operatively). X-rays and CT scans provide the surgeon with details needed in the planning process. Is there infection that must be dealt with? What’s the patient’s general health? (Is the patient healthy enough to have another major surgery)? How much bone loss was caused by the first surgery? Is there already a leg-length difference that could get worse with a second (revision) procedure where more bone will have to be removed?

Other factors the surgeon must look at include the presence of cement and/or hardware (metal plates, screws, wires) that must be removed; location of blood vessels, nerves, and ureters (tube from the kidneys to the bladder) in relation to the acetabulum (hip socket); scar tissue from previous surgeries; and damage from radiation for cancer in the pelvis.

To aid surgeons in evaluating and treating patients with bone loss of the acetabulum (hip socket), orthopedic surgeons from three large medical centers wrote an article addressing all of these issues. They presented (with X-rays and drawings) the many different types and patterns of bone loss surgeons may encounter. Classification methods to describe bone loss of the acetabulum and articular (hip joint) surface are also provided.

In this article, the surgeons gave detailed descriptions of reconstruction methods. Some of the procedures involve different ways to perform osteotomies (removing portions of bone) to alter the angle of the bone or to lengthen the femur (thigh bone). An osteotomy can help make up for significant leg length differences.

Bone grafting techniques (e.g., impaction grafting, structural allograft, morcellized bone graft) used in the reconstruction of the hip are discussed. Long-term results from other studies are reviewed to help surgeons identify ways to aid their own patients in gaining the best results for the longest period of time.

Types of acetabular sockets (or cups) are examined using X-rays, pictures, and intraoperative photos and ways to secure the implants are presented. Cases discussed involve patients with such severe bone loss that sometimes the new hip implant has to be custom made to fit the patient.

In severe cases like these, the surgeon has to find inventive and creative ways to attach the implant. When the bone quality is so poor or the defect so large that there’s no place to firmly anchor the component part, a special triflange component is used. This device, made to bridge large gaps in the bone, is a featured topic.

And to add to the surgeon’s challenge, cost considerations, the ability of the patient’s body to create bone ingrowth around the implant to secure it, and the long-term effects of stiff metal interfacing with living bone must all be reviewed and evaluated.

In summary, sometimes patients need a revision of their original (primary) hip joint replacement. This is a complex and challenging procedure for the surgeon, especially when any of the factors affecting the bone discussed here are present.

Every effort to manage patient pain is made using conservative means before considering revision surgery. When the problem is infection, other treatment should be tried first (e.g., antibiotics, debridement). When weakness is causing pain and difficulty walking, physical therapy should be provided. But in the end, when all other efforts to salvage the joint fail, revision surgery may be necessary. And that’s when the information in this article will be of great value to the surgeon.

Do Steroid Injections in the Hip Before Hip Joint Replacement Cause Infection?

In this look back over the records of 96 patients, surgeons evaluated whether or not a steroid injection into the hip was linked with infection after hip replacement. They conducted the study because there have been previous reports that this may be the case. And since steroid injections are often used to diagnose the problem and then used as an alternative to surgery, this information is important.

Anyone who has suffered enough hip pain to end up with a hip replacement doesn’t need the extra aggravation of a joint infection that requires another surgery. In this study, there were two groups of patients evenly matched by age, sex (male or female), diagnosis, and year of surgery. All of the patients had a hip replacement (referred to in medical terms as a total hip arthroplasty or THA). One group had steroid injections two to six months before the replacement surgery. The second (control) group did not have any steroid injections into the hip.

There was no difference between the two groups in regards to hip joint infection after the hip replacement. In fact, there were no differences in relation to any complications (e.g., dislocation, fractures, need for revision surgery). Previous studies have shown similar results but also some very different results. One study reported a 30 per cent rate of hip infection after hip replacement when a steroid injection was given before the procedure.

Since that time, there has been increased attention on the part of orthopedic surgeons when considering steroid injection into the hip. The concern for joint infection after replacement is very real. Experts recommended using caution and good clinical judgment when using steroid injections to relieve hip pain for osteoarthritis. And surgeons were advised to avoid using this technique within a two-month period of time before hip replacement.

So the question is raised once again — steroid injection before hip replacement: yes or no? The authors make several suggestions. First, a reminder that there are many potential reasons why a patient may develop joint infection after hip replacement. Nutrition, comorbidities (presence of other illnesses or diseases), and type of body (size, shape) are just a few considerations.

Second, their study was fairly small so different results might be found with a larger sample size. Only 15 of the 96 patients had an injection two months before the surgery. Again, this may be too small of a sample set to show significance. And only one surgeon performed all of the injections using the same technique(s) with each patient. Special care was given to keep everything sterile in order to reduce the risk of infection. Any of these (or a combination of these) factors could have contributed to the positive results.

The authors concluded that previous reports of infection after hip replacement linked with preoperative steroid injections must be taken seriously. Steroid injections into the hip before total hip replacement are not contraindicated. But until researchers are able to clearly identify cause and effect, and risk and benefit of this treatment, it is best to continue following current precautions.

Osteoarthritis: It’s in the Genes

Researchers have noticed a very curious thing. People of European descent are the only ones who develop primary osteoarthritis (OA) of the hip. Those individuals who are of African or Asian lineage are much less likely to develop this condition. In fact, according to this article, primary osteoarthritis is completely absent in true Asian and African people. Only those adults who are a mixture of African (or Asian) and European develop primary OA.

Primary osteoarthritis of the hip refers to loss of joint space from a degenerative process affecting the hip joint cartilage. It only occurs in adults 55 year old or older. It is not caused by previous hip problems in childhood like Perthes disease, trauma, developmental dysplasia, or slipped capital femoral epiphysis (SCFE). Other potential causes for the arthritic changes are also ruled out (e.g., rheumatoid arthritis, Paget disease, sepsis).

Naturally, after making this discovery that there is a difference in rates of hip replacement between Europeans and non-Europeans, the scientists started looking for an environmental or genetic explanation. They used data from family and twin studies to look for factors that might explain the European versus non-European differences in rates of hip osteoarthritis. They did not find any environmental risk factor that could account for these differences. But there were some genetic links.

Putting this finding into statistical terms, here’s what they found. Primary hip osteoarthritis is the reason for 65 to 70 per cent of all hip replacements (around the world). And 100 per cent of those hip replacements are in people with European ancestry. Intermarriage among Europeans and Asians or Africans eventually (over 20 generations) results in the same risk for osteoarthritis as among those who are 100% European.

Curiously, having osteoarthritis (OA) in any part of the body (e.g., hip, knee, hand) does NOT increase the risk of developing arthritis in any other part of the body. So having hip OA does not mean you will be getting knee arthritis later (or vice versa).

What is the importance of this discovery? Knowing there is a genetic cause for osteoarthritis (OA) could help scientists find the molecular basis for OA. This could lead to ways to stop it from starting in the first place! Linkage analysis (a type of genetic study) is the next step in drilling down to the specific genetic component of this disabling disease.

But let’s go back to the notion that environment is not a factor in OA among Europeans and their descendants. What about the role of obesity, joint injury, sports activity, and overuse of the joints through work and play? We have always thought osteoarthritis is a degenerative disease from joint wear and tear. But the complete absence of this disease in Africa and Asia where heavy physical activity is so common makes that belief obsolete.

And what about African Americans and American Hispanics? There is some intermarriage but is it enough to raise their risk of developing osteoarthritis? Based on Medicare data for hip replacement surgeries, African Americans account for only half the number of joint replacements. Their ancestry consists of 20 per cent European DNA. American Hispanics with 50 per cent European DNA have up to one-half the rate of hip replacements as European-descent whites.

In conclusion, there is enough evidence now to prove that primary osteoarthritis is a genetic disease. In other words, it is inherited and only among people of European descent. So if you don’t have the European gene, you are safe. But chances are — if you live in the United States (or are the product of an interracial marriage), you won’t be exempt from this condition. And since it is a genetic disease based on European lineage, moving to Africa or Asia won’t help either!

Total Hip Replacement: Needed But Not Always Possible

Even though hip pain from osteoarthritis can be very debilitating and disabling, hip replacement is still an elective procedure. Elective means it is not required because of a life-threatening condition, but rather, a choice based on personal needs and preferences.

Many more older adults are choosing (even demanding!) this surgery in order to stay active longer. In fact, it is anticipated that there will be an almost 200 per cent increase in the number of hip replacements done in the United States over the next 20 years.

But not everyone who wants a new hip is a good candidate for surgery or in particular, hip replacement surgery. In this review article, surgeons from Ohio State University present for us, what is known about risks related to total hip arthroplasty (THA, another name for total hip replacement).

First, studies show there is up to a 7.4 per cent risk of major problems during or after surgery. And more significantly, there is even a 0.8 per cent risk of death after joint replacement (hip or knee). With the new upcoming pay-for-performance Medicare program to control costs, surgeons will be penalized for poor results and rewarded for good outcomes. That means patient selection (choosing patients likely to have the best results) will become increasingly important. And the opposite is true, too — identifying patients at increased risk for complications with surgery will dictate who might not qualify for the procedure.

Just what are the risk factors that put patients in danger of complications, problems, and adverse events associated with total hip arthroplasty (THA)? Heart disease is the number one health problem that complicates elective surgery. Three-fourths of all major problems after joint replacement surgery (hip or knee) are directly linked with the cardiovascular system. High blood pressure, blood clots, valve disease, heart attacks, previous history or heart surgery such as the implantation of a stent or balloon angioplasty top the list of significant (and potentially life-threatening) risk factors.

Other health conditions surgeons must watch for in patients considering total hip replacement include rheumatoid arthritis (RA) with psoriasis (skin lesions increase risk of infection, drugs for poor wound healing), organ transplantation, alcohol abuse, HIV, obesity, blood clotting disorders, and eating disorders or malnutrition. Even things like dental disease (cavities, abscesses, gingivitis) can put you on the sidelines.

And there’s more! Tobacco use (especially smoking), kidney disease, sleep apnea, history of cancer, long-term use of steroid medications, diseases of the blood vessels in the legs, diabetes, and lung diseases must all be taken into consideration as potential risk factors. The authors carefully describe the details of each category of risks and the possible influence these factors have on adverse events after hip replacement.

Finally, it may seem like anyone of any age can get a hip replacement. But older age does put adults at increased risk for medical complications (and death) associated with joint replacement. Sixty-five years of age seems to be the cut-off point for low-to-high risk. Risk starts to increase after age 65 to the point that by age 85, the risk of death after hip replacement is nine times higher in adults 85 and older.

Paying attention to risks before agreeing to perform surgery is called risk stratification. This is something surgeons are giving more and more attention to as older adults who have multiple health problems ask for joint replacements. Patient safety is everyone’s concern.

Knowing that most complications occur in the first few days after surgery puts the burden of prevention on surgeons first to select the best candidates for surgery. But as the authors note in their final conclusion — less than half of all patients who end up with life-threatening complications after surgery have any obvious risk factors beforehand. To use a gambling term — that certainly “ups the ante.” More studies are needed to provide an evidence-based risk stratification model that can be used to prevent and reduce all post-operative problems, but especially life-threatening complications.

Big Question: Do Cemented Implants Hold Up Better Than Cementless?

When joint replacements are put in place, they can be cemented in place or the surgeon can use a cementless type that fills in with bone. Both are still commonly in use but many surgeons have switched to all cementless. They made this switch to avoid implant loosening that is more common with cemented implants. Loosening aside, the question of whether cemented survive longer (and better) than cementless has come up many times. This meta-analysis and systematic review may provide some answers.

Researchers from the Rothman Institute of Orthopedics at Thomas Jefferson University Hospital in Philadelphia took the time to examine the literature and analyze the combined results.

Out of 3,488 potential articles, 81 met the necessary criteria to be included. About half (45) were studies on the long-term results using cementless acetabular (hip socket) components. One-third (29) reported the long-term outcomes of cemented acetabular parts. And the rest (7) compared the two together. All acetabular implants were made of polyethylene (a type of plastic).

But we will warn you up front that it is clear that whether or not a component part survives (and how long it holds up) isn’t only dependent on the cemented versus cementless factor. There are other variables that can affect acetabular survival. Some are based on the component itself such as surface finish, how long the polyethylene itself lasts (i.e., shelf life), and the method of sterilization for the component part. Some are patient-based influences including bone quality, patient activity level, and patient size (body mass index). And there are surgeon-based factors (e.g., level of experience and expertise, type of surgical approach used for the procedure).

Very few of the articles of high enough quality to be included adjusted or controlled for these other variables. That is a major limitation in answering the question of how using a cemented versus cementless implant compares when it comes to survivorship. There are just too many other variables that could be making the difference.

With that fact in mind, there were no major differences observed in revision rate between these two types of implants based on the cement versus no-cement factor. And revisions because of aseptic (without infection) loosening were equal between the two groups. However, more cemented acetabular components were still in place 10 years or more after implantation indicating longer survivorship of the cemented cup.

Age may be something important to consider. When comparing revision rate between cemented and cementless cups, they found an interesting phenomenon. Younger patients did better with uncemented cups. Older patients had better results with the cemented cups.

There may not be enough evidence to support the decision to switch to cementless acetabular components to avoid loosening. The results of this systematic review and meta-analysis suggest that despite improvements in cementless implants, their durability and survivorship doesn’t match cemented implants. Thus, the literature does not yet prove the superiority of the cementless acetabular component over the cemented type.

More and more older adults are expected to have hip replacements in the coming years. With the current high rate of revisions, surgeons are seeking ways to avoid second surgeries for these patients. More research is needed to sort out the various factors (or combination of variables) that may be influencing revision rates and survivorship of hip implants. Finding the optimal choice of fixation type will have to be the focus of future studies to reach a final answer to the question of which is better: cementless or cemented?

Hip Preservation Surgery for Femoroacetabular Impingement

Surgeons (and patients) will find this review article on current treatment concepts for femoroacetabular impingement (FAI) of interest. Studies show that the anatomic abnormalities associated with this disorder are more complex than originally thought. Understanding the bony deformity and subsequent changes in how the hip moves is important when planning treatment for this problem.

Impingement refers to some portion of the soft tissue around the hip socket getting pinched or compressed. Femoroacetabular tells us the impingement is occurring where the femur (thigh bone) meets the acetabulum (hip socket). There are several different types of impingement. They differ slightly depending on what gets pinched and where the impingement occurs.

The surgeon must pay attention to the effect of abnormal kinematics (movement) caused by FAI on the surrounding soft tissues of the hip. This is an important step in order to assure good outcomes and patient satisfaction. Repetitive pinching of the labrum (rim of fibrous cartilage around the hip socket) leads to more injuries of the joint and eventual arthritic changes.

The condition affects many athletes who are interested in getting back to a pre-injury level of sports participation. Treatment failure is most common among patients with significant early osteoarthritis, so early intervention is advised.

Many orthopedic conditions can be treated conservatively (without surgery) and that is often the first step with femoroacetabular impingement (FAI). A physical therapist helps the patient regain soft-tissue mobility, hip muscle strength, neuromuscular control, and postural balance. Currently, there aren’t enough published studies providing evidence that nonoperative management of this condition is effective. That doesn’t mean it isn’t helpful — we just need more research in this area to prove it.

Surgical correction does have a good track record. Surgery can be done with an open incision or with the less invasive arthroscopic approach. The surgeon’s choice depends on the patient’s age, type and severity of impingement, and amount of damage to the hip cartilage. The main objectives of surgery are to relieve pain, improve function (including return to daily and/or sports activities), and prevent hip arthritis.

The authors of this article provide a review of the pathophysiology, etiology, type of lesions, and management options for FAI. MRI images, intraoperative arthroscopic images, and X-rays are included. The surgeons use these visual tools to describe the condition, discuss surgical management, and instruct surgeons in examining all of the mechanical factors affecting patients with FAI.

The focus on dynamic and static mechanical factors in the development of FAI is new. Dynamic factors include the well-known loss of normal structure and joint mechanics that cause the pinching. But other associated dynamic mechanical factors are being highlighted for the surgeon’s consideration.

These include the extra-articular (outside the joint) factors associated with impingement. This can include femoral retroversion, femoral varus, trochanteric impingement, and impingement of the anterior inferior iliac spine.

Static factors (the way the hip is formed) cause increased abnormal stress and uneven load between the femoral head and the hip socket during standing activities. These include hip dysplasia, femoral anteversion, and femoral valgus. In many cases, there are combined patterns with both dynamic and static effects contributing to injury patterns with FAI.

The authors summarize their review of concepts related to femoroacetabular impingement (FAI) by reminding surgeons that FAI is probably the most common cause of early cartilage and labral damage in the hip of young athletes complaining of hip pain. The ability of these areas to heal is limited by the lack of blood supply. Surgery (whether by open or arthroscopic technique) can correct the deformity, thus relieving pain and preventing further damage to the hip joint.

With correct treatment early on, up to 90 per cent of athletes affected by FAI can return-to-sports successfully. The important ingredient to successful surgical treatment is careful attention to all aspects of the deformity. This includes recognizing static and dynamic mechanical factors (often present at the same time) and addressing them during the surgical procedure.

Microfracture: Good For the Knee but What About the Hip?

Defects, holes, or lesions of the articular cartilage (surface of the joint) can be treated with a surgical procedure known as microfracture. The surgeon creates tiny holes in the surface of the joint at the site of the problem area. Blood seeps through from the bone marrow and stimulates a healing response. This technique has been used for the knee but can it be just as useful for the hip?

That’s what the authors of this study set out to find out. They treated 20 patients with full-thickness acetabular cartilage defects with microfracture. Full-thickness means the damage done to the surface of the joint went clear down to the bone underneath. These are called osteochondral lesions. Acetabular refers to the acetabulum, the hip socket. In each case, the reason the patients all had this type of damage was because of a condition known as femoroacetabular impingement or FAI.

Femoroacetabular impingement (FAI) occurs in the hip joint. Impingement refers to some portion of the soft tissue around the hip socket getting pinched or compressed. Femoroacetabular tells us the impingement is occurring where the femur (thigh bone) meets the acetabulum (hip socket). There are several different types of impingement. They differ slightly depending on what gets pinched and where the impingement occurs.

Over time, this pinching or impingement of the labrum can cause fraying and tearing of the edges and/or osteochondral lesions at the impingement site. For these 20 patients, most of the defects were in the front part of the acetabulum. Treatment was advised to help decrease pain and prevent further hip degeneration.

There aren’t very many studies reporting the results of using microfracture for hip osteochondral lesions so this study is an important one. The surgeons evaluated the effectiveness of the microfracture treatment by performing a second arthroscopic examination some time later (a range between 5 months and four years after the procedure).

All but one patient had a good result with repair tissue rated as “good quality” and filling in 95 per cent of the defect. The one “poor” result had only one-fourth of the lesion filled in and that with only fibrous cartilage, not true, healthy osteochondral tissue.

The authors concluded that microfracture for acetabular (hip) cartilage lesions can produce good results. This procedure should be considered for some patients with femoroacetabular impingement who develop painful osteochondral lesions. It is a simple and cost-effective surgical approach to the problem with good results.

News About Treating Infections After Hip Replacement

Orthopedic surgeons performing total hip replacements (known as total hip arthroplasty or THA) will be interested in this update on the treatment of post-operative infection. New developments and advances in this area deserve attention. Since there are so many different ways to approach the problem, the question is: which treatment gives the best results?

To help determine optimal strategies for managing post-operative hip infection, the authors reviewed all the current studies done in this area. They found some excellent information coming from Europe. There surgeons use a formula or algorithm to select the right procedure for each patient.

The surgical approaches to this problem include: 1) irrigation and debridement, 2) one-stage exchange, 3) two-stage exchange, and 4) resection arthroplasty. Here’s a brief summary about the role and results for each one.

Surgical irrigation and debridement is often used for many other problems of this type. The surgeon uses a saline solution to irrigate or wash away as much of the infection as possible. Then any infectious or dead tissue is removed (debrided). The failure rate for this type of treatment is pretty high, so this treatment method is rarely used by itself.

Instead, the one- or two-stage procedures are combined with irrigation and debridement. Once the surgeon has cleared out the infection, then the implant can be removed, antibiotic treatment applied, and the implant replaced. In a one-stage procedure, this is accomplished in one surgery. The best patient for a one-stage exchange is the person with an acute infection (early after the first surgery to put the implant in). In these cases, there hasn’t been enough time for the implant to form bone around it, locking it in place.

Later infections or chronic infections (infections that have not responded to treatment and are still present months after the first surgery) are being treated with a two-stage procedure. In such cases, irrigation and debridement are done, then a portion of the implant is removed. The surgeon leaves behind the cemented area. This approach helps reduce how much bone has to be removed.

In the two-stage procedure, a special spacer is inserted into the area where the top of the implant has been removed. The spacer keeps the femur (thigh bone) from sliding up into the acetabulum (hip socket). The spacer is covered in an antibiotic. Later (when the infection is cleared up), the spacer is removed, the area is irrigated and debrided, and a new implant is put in place once again.

For all patients regardless of procedure approach, intravenous antibiotics are an essential part of the treatment. At least one study has shown that intravenous antibiotics can be given for two weeks and then the patients are switched to an oral (pill by mouth) antibiotic. Early studies show this method is effective and the infection does not return. More studies will be needed before this becomes a standard treatment method.

The authors conclude that infection after hip replacement can be a challenging problem to treat — especially if it’s not caught early and becomes chronic. The hope is that with newer techniques, post-operative joint infections of this type will respond faster and better with improved outcomes. Treatment patterns are definitely changing so surgeons can expect to see more on this topic in the future.

Routine Imaging of Hip Recommended After Joint Replacement

Imagine you had a total hip replacement six years ago and everything went just fine. Then bam! You develop pain and swelling somewhere around the hip or thigh. What’s happening? With the aid of X-rays, CT scans, and/or MRIs, the surgeon diagnoses a condition known as osteolysis. The images suggest this problem didn’t just happen but was developing over time.

Osteolysis or bone loss after total joint replacement (knee or hip) can be a problem. Tiny flecks of bone and debris from the backside of the implant lead to osteolysis. Over time the implant can come loose or the bone can fracture.

The authors of this instructional course for orthopedic surgeons recommend routine monitoring starting five years after total hip arthroplasty (THA or replacement). Follow-up X-rays are advised every two to three years after that for as long as the patient has the implant.

The authors discuss the role of X-rays, CT scans, and MRIs in diagnosing and following patients with THA. Risk factors for osteolysis are presented along with the idea that anyone at risk should be monitored even more closely.

Not everyone with osteolysis has symptoms (pain, swelling, loss of motion), especially early on. The only way to know for sure if there is any bone loss is to take an X-ray. Osteolytic lesions look like someone took a bite out of the bone. But X-rays are only a two-dimensional view of a three-dimensional object. So although they show there is a problem, X-rays aren’t enough to tell the surgeon the full extent of the defect.

That’s where CT scans and MRIs come in. These more advanced forms of imaging are considered supplemental. They can be modified to reduce the amount of distortion or “artifact” shown on images caused by the metal. This metal artifact reduction protocol gives the radiologist and surgeon a better view of the bone and soft tissues around the implant compared with regular, traditional CTs or MRIs.

Sometimes both types of imaging studies are needed. That’s because they show different structures: CTs scan the bones whereas MRIs are better at showing changes in the surrounding soft tissues. But does everyone need all of these tests? Not really. The timeline (beginning five years after the patient gets the hip) is the first criteria for testing.

The patients at greatest risk of osteolysis are those who are younger and more active. Men tend to fall into this category more often than women. Because this type of osteolysis is linked with wear debris, it takes time to develop. That’s why routine screening isn’t recommended until five years out. And, of course, as more time passes, the risk increases.

Certain types of implants are more likely to shed metal debris with use. The first ultra-high molecular-weight polyethylene (UHMWPE) implant components (parts) used tend to wear out faster than the newer highly cross-linked UHMWPE implants. So anyone with the conventional UHMWPE should be assessed for sure.

What happens if osteolysis is detected? Well, no immediate treatment is needed. The patient is followed more closely (every four to six months) instead of every two or three years. If there are signs that the lesion is getting larger or worse, then the patient may be a candidate for surgery. Serial (repeated) X-rays shows the rate of progression (how fast and how much worse the osteolysis is developing).

Treatment of osteolysis following hip replacement is not the focus of this instructional course. Instead, surgeons interested in reviewing the indications for when and how to use imaging studies to screen for the presence of osteolysis and then monitor the progression of disease will find this information helpful. A dozen photos of X-rays, CT scans, and MRIs are provided to help illustrate what to look for on both sides of the hip implant (acetabular or socket-side and round head at the top of the femur or thigh bone).

Is The Evidence For or Against Mini-Incision for Hip Replacement?

Can you guess how many people have a total hip replacement in the United States every year? Would you be surprised to know that at least one-quarter of a million total hip replacements are done annually? And it is expected that over the next few years, that figure will more than double.

With so many people in the Baby Boomer generation now getting a hip replacement, it’s natural that they seek out this surgery. More and more hip replacements are being performed with a mini-incision (less than 10 centimeters or two and a half inches long). Surgeons need to know what evidence there is to favor this approach when advising patients which way to go (mini-incision versus traditional open surgery).

To help with these management decisions, a group of researchers from the Health Services Research Unit at the University of Aberdeen in Scotland conducted a very thorough electronic literature search. They searched on-line for any and all studies comparing the results of a mini-incision approach to hip replacement to the results using a standard incision.

They found 15 studies that met the eligibility requirements for good quality studies with a total of 1857 patients (when all combined together). The studies were not all equal in quality or design. For example, the number of subjects ranged anywhere from 20 to 219. In some studies, the surgeon had a great deal of experience performing the minimally invasive procedure. Other studies noted that the cases involved were with surgeons just getting started with this approach and technique.

Follow-up varied from six weeks to three years. But outcomes could be compared by looking at amount of blood lost, length of operative time, number of days in the hospital, and complication rate. Complications included dislocations after surgery, level of pain, excessive blood loss, nerve injury, infection, fractures, blood clots, and the need for a second (revision) surgery.

Analysis of all the data showed that there were small differences in early results but in the end, no major differences in outcomes between the two groups. Sure, there was a bit less blood lost during the mini-incision procedures and the hospital stay was a day or two shorter. But there were no significant differences between the two groups when looking at complications or revision rates.

The authors point out the fact that the available studies were all fairly short-term. So long-term results cannot be compared at this time. Without the benefit of 10 to 20 year studies, it’s not clear if the mini-incision approach provides any major advantages over the traditional standard-incision surgery.

With more direct marketing to consumers, a greater number of American adults are seeking what is now referred to as “the operation of the century” — total hip replacement. Surgeons must be prepared to guide patients through the decision-making process based on clear evidence, not advertising hype. And before that can be possible, more high-quality, well-designed studies are needed.

At this point all that can be said for sure is there aren’t any major differences in short-term results between standard and mini-incision for total hip replacement. The authors of the study summarize it well in a single statement: Current evidence is not strong enough to support one surgical technique over the other.