Nonoperative Treatment of MCL Tears in ACL/MCL Injuries Does Not Increase ACL Retear Rates

The treatment of multi-ligament tears in the knee has had much controversial debate through the years. Many orthopedic surgeons feel treating the MCL and ACL at the same time with surgery provides the best results for stability. Those who do treat the MCL nonoperatively will tend to use a brace of some type. There is now a push to operate on the MCL during the acute phase following an ACL/MCL injury. Those who do this have an opinion that it will lower the revision rates following the ACL reconstruction.

If you have read any of our previous blogs regarding ACL injuries, or read any of the previous research that Dr. Shelbourne and staff have published regarding the history and treatment of ACL injuries, then you have read that when Dr. Shelbourne first started practicing in the early 1980’s, he also treated MCL injuries surgically and treated these injuries acutely. By doing so, he found that patients developed a very stiff knee, arthrofibrosis, and were overall very unhappy with their outcomes. This is why the “accelerated rehab” program became so well known. It appears we are coming full circle and going back to doing things that we have learned do not create a better outcome. More surgery performed on a joint leads to increased risks and complications. If we can have a means of treating something without a surgical procedure and get the same outcomes, why wouldn’t we strive for this?

Mining Our Data for an Answer

This past year, our staff looked at our data regarding these types of injuries to the ACL/MCL and performed a study to determine if there has been a difference in ACL retear rates or postoperative stability between those with ACL/MCL injuries and those with isolated ACL injuries when the MCL was treated nonoperatively, with possible casting, before the ACL reconstruction. Their the hypothesis was that those with ACL/MCL tears would have similar retear rates and postoperative stability compared to those with isolated ACL tears.

Between 1982 and 2022, Shelbourne Knee Center had 6047 patients who were planning to have an ACL reconstruction and enrolled in the study based on the following inclusion criteria: primary ACL reconstruction using a patellar tendon graft and a minimum of one year of follow-up. Patients were excluded with revision ACL, lateral side injury or posterior cruciate ligament involvement, or lacking postoperative KT data. (KT is a device used to check stability of the ACL at every office visit).

The patients were divided into two groups, isolated ACL reconstruction (N=5670) and ACL/MCL (N=377). Patients in the ACL/MCL group were initially treated nonoperatively to get the MCL to heal and if needed, casted with the knee at 30 degrees of flexion, changed weekly until a solid endpoint was achieved and patients could bear full weight. At this point, preoperative rehabilitation was started, and range of motion was normalized before the ACL reconstruction.

After the ACL reconstruction, the patients followed the same accelerated rehabilitation program. A KT test was performed and the manual maximum difference between knees, in millimeters, was used for analysis. The graft retear rate was determined through subjective surveys sent yearly to each patient after surgery. To reduce confounding bias in the analysis, the ACL/MCL patients were control-matched 1:1 to the isolated ACL injury patients based on sex, age, postoperative activity rating, and surgery timing, which led to a total of 304 patients in each group.

The mean age for both groups was similar with the ACL/MCL group—24.6 years—and the ACL reconstruction group—24.9 years. They showed identical rates of males, postoperative activity rating greater to or equal to 7, and subacute surgery at 66.4%, 90.4%, 73.0%, respectively. The KT manual maximum difference for the ACL/MCL group was not statistically significantly different when compared to the isolated ACL reconstructed group (1.8mm versus 1.6mm; p=0.196). The ACL retear rate for the ACL/MCL group was 7.9% compared to 6.6% for the isolated ACL reconstructed group, which was also not statistically significantly different, p=0.531.

The conclusion of this study shows that when the MCL is treated nonoperatively with casting before the ACL reconstruction, postoperative stability and rates of ACL retears are similar to those with an isolated ACL tear. Therefore, performing surgery for the MCL when torn in conjunction with an ACL tear is not necessary. This surgery can, and should be, avoided as nonoperative treatment with a cast and proper rehabilitation before an ACL reconstruction will result in similar outcomes when compared to those with isolated ACL tears.

This paper was accepted for podium presentation at APTA Combined Sections Meeting for 2024, and for poster presentation at the AOSSM meeting in 2024.

References

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