This is a report on the use of arthroscopy in the treatment of femoracetabular impingement (FAI) in children. FAI refers to a pinching of the soft tissues around the hip joint where the femoral head (top of the thigh bone) bumps up against the acetabulum (hip socket). Athletes between the ages of 11 and 16 years old with different types of FAI were included.
The reason FAI occurs is because there is an abnormal relationship between the femoral head and neck. The junction where these two structures meet is shortened or rotated from normal. This change from normal is referred to as the femoral head-neck offset.
The most common causes of this problem are pediatric conditions such as Legg-Calvé-Perthes disease and Slipped Capital Femoral Epiphysis (SCFE). In some cases, FAI occurs because of the way the bones are formed with slight variations from the norm. The children in this study had no obvious secondary cause of their FAI. It was most likely the result of anatomic variations of unknown origin.
Repeated flexion (bending) of the hip is the movement that makes the impingement the worst. Over time, it can lead to tears of the labrum and early signs of arthritis. The labrum is a dense ring of fibrocartilage that is attached around the rim of the acetabulum. It helps make the socket deeper and more stable for the femoral head.
FAI can be treated conservatively. In fact, nonoperative care is always recommended first. This usually consists of at least six weeks of nonsteroidal antiinflammatory drugs (NSAIDs), steroid injections, physical therapy, and activity modification.
Children who continue to have disabling pain despite conservative care may consider surgery as the next option. Pain severe enough to keep an athlete on the bench and unable to participate is the most common reason for surgery to correct this problem.
Arthroscopy is routinely used in surgeries for adults with FAI. But the anatomy of children is different enough that the same techniques can’t be used in exactly the same way. The advantage of arthroscopy for this procedure is that it allows the surgeon to move the hip and test to make sure the impingement is no longer present.
The exact surgical technique used with the 16 adolescents in this study depended on what the surgeon found during the procedure. Femoral head-neck osteoplasty was performed most often. Osteoplasty means surgical repair or alteration of the bone.
In some cases, the labrum and acetabular rim were trimmed to prevent further impingement. If the labrum was torn, suture anchors were used to reattach it to the acetabular rim. If there was too much capsular material, the surgeon removed a portion of it. Any defects in the joint surface were repaired at the same time. This procedure is called a chondroplasty. About half the patients had a chondroplasty of the femoral head. The other half had a chondroplasty of the acetabulum.
After surgery, patients were placed in a special brace to control hip motion. Walking was allowed with crutches. Scar tissue formation was minimized by using a continuous passive motion (CPM) machine for the first two weeks.
Everyone was supervised by a physical therapist for their postoperative rehabilitation program. The therapist progressed each child through motion and strengthening exercises with a return-to-sports within three months’ time.
Results were measured using function, activity level, return-to-sports, and patient satisfaction. The children were followed at regular intervals for two full years. Everyone was able to return to their favorite sports activities. They were able to do so at a level equal to their ability before the surgery. Satisfaction was very high. For those children who were still growing, the surgery did not interfere with further bone growth.
The authors conclude that arthroscopic repair of FAI in older children and teens is both safe and effective. With newer surgical instruments and improved arthroscopic techniques, surgeons can repair defects in the hip (including impingement) without an open incision.
Arthroscopic repair is even possible in children whose growth plates are still open and have not completely fused yet. Most of the repair is done on the acetabular side of the joint. The authors suggest this approach will help prevent the development of other problems, especially deformity and stopped growth of the physis (growth plate).