History of ACL Injury and Repair

Over 35 years have passed since the first report of anterior cruciate ligament (ACL) knee injuries in military recruits. In those days, arthrotomy (open incision) and repair of the torn ligament was attempted. The first study and report of results was published in 1976. In this follow-up study, long-term patient results are reported for those same patients.

Since those early days, surgeons discovered that ACL reconstruction is much more successful than ACL repair. Instead of reattaching the torn tendon, tendon material is taken from either the patellar tendon or the hamstrings and used to replace the damaged ACL. So, although today’s patients aren’t likely to have the same procedure as those original West Point Cadets, the long-term results are still important. They can be used to compare to long-term results from techniques currently used to restore ACL function.

Arthroscopy is used for most ACL procedures today. This minimally invasive procedure has reduced many of the complications associated with open repairs. Many of the circumstances around the surgery are different today. It’s no longer an in-patient procedure with long pre-surgery and postoperative hospitalizations. In the 1970s (before arthroscopy), even partial ACL tears were diagnosed with arthrotomy.

One of the other major differences in the treatment of ACL ruptures then and now is the post-operative care. Back then, patients were placed in a long leg cast for six weeks. Today, some patients don’t even use a brace and can put weight on the leg right away (as tolerated).

As a means of measuring results over time, each of the former military cadets was interviewed about their motion, pain, function, and satisfaction with the open repair they had years ago. Five years after the first surgery, cadets were asked, If your knee was 100 per cent before injury, what would you rate it now?. It turns out that the outcomes of that first five-year study were predictive of the long-term results. Cadets who gave their knee a poor rating at that time, were more likely to end up with an unstable knee 30 years later. And in this study, more than half ended up with a poor result.

Some patients may have had a worse outcome than reported. As activity levels declined over the years, the patients were less likely to complain they were unsatisfied with the results. It may be a gradual adjustment to loss of function as well the aging factor.

The authors suggested (based on evidence from other studies) that our understanding of ACL injuries today help explain the poor outcomes of the West Point cadets. We know that younger patients (under the age of 22) seem to fare the worst after ACL reconstruction. Most of the injured cadets were around 20 years old.

Ligament rupture close to the bone has a better chance of recovery. Most of the cadets had midsubstance (middle of the ligament) tears. And football injuries have the worst results (skiing injuries seem to recover the best). A large number of the West Point injuries were noncontact football injuries.

Using the data from this study, the authors confirm what other studies have shown — that the condition of the knee meniscus at the time of the ACL repair is important. Patients with meniscal injuries along with ACL tears have lower long-term outcomes.

As this historical study has shown, much has changed in the treatment of ACL injuries. Reconstruction rather than repair has resulted in much more positive outcomes. Arthroscopy has made early diagnosis and intervention possible. And the diagnosis is more accurate and reconstruction easier. Having newer clinical tests and MRIs available has also helped in the diagnostic process.