Abstract
Objectives:
Tears of the medial collateral ligament (MCL) are the most common knee injury. Conservative treatment of isolated MCL injuries tears often provides good functional outcomes. With the exception of stener lesions, most high grade isolated MCL tears are initially managed with nonoperative treatment and may be indicated for repair or reconstruction if medial joint space gapping persists after six weeks. There is a paucity of data on the outcomes of nonoperative management of MCL injuries stratified by location of the tear. This data could help determine which of these tears are most likely to achieve adequate healing without surgical intervention. The objective of this study was to assess residual laxity of nonoperatively treated grade II and III isolated MCL injuries based on location of tear (proximal, midsubstance, or distal).
Methods:
Patients aged 14 and above who sustained an acute isolated clinical grade II or III MCL tear and were evaluated with a knee MRI between 2010 and 2023 at a single institution were included in this study. Patients with multiligamentous knee injuries, previous knee surgeries on the affected side, less than six-week follow-up from injury, or operative management of MCL tear were excluded from the study. Patient demographic data, presence of concomitant meniscus injury, knee surgeries, location of MCL tear on MRI, medial joint space gapping on valgus testing at 0° and 30° of flexion, range of motion, return to sport, and patient reported outcomes were collected. The primary outcome was resolution of medial joint space gapping (laxity) at 0° and 30° of flexion at final follow-up. Secondary outcomes analyzed by tear location included timing to resolution of laxity, final grade if persistent laxity, and subjective patient reported outcomes. MCL tear grade was defined as grade I: no valgus laxity, grade II: valgus laxity at 30° of flexion, and grade III valgus laxity at 0° and 30° of flexion. Grade III was further subdivided based on medial joint space gapping: 3-1+ gapping of 3-5mm, 3-2+ gapping of 6-10mm, 3-3+ gapping >10mm. The data were analyzed using Fisher Exact tests.
Results:
Initially, 622 patients from a single institution with MCL tears on MRI were retrospectively identified. 49 of those were clinically grade II or III without other ligamentous injuries. Twenty-one patients with less than six weeks of clinical follow-up were excluded. Two patients went on to require repair of proximal MCL tears and were excluded. The remaining 26 patients managed nonoperatively included 18 (69.2%) proximal tears, 4 midsubstance tears (15.4%), 4 distal tears (15.4%). None of the distal tears were stener lesions. The average patient age at time of injury with proximal tears was 42.1 years, midsubstance was 43.5 years, and distal was 32.8 years. Seventeen (65.4%) patients had no clinically appreciable medial joint space gapping on exam at final follow-up with an average of 65.1 days to stable test. 4/18 (14.8%) proximal tears had persistent laxity at final follow-up at an average of 116 days from injury, 2/4 (50%) midsubstance tears had persistent laxity at an average of 204 days from injury, 3/4 (75%) distal tears had persistent laxity at an average of 90 days from injury (p=0.083). All distal tears with persistent laxity had 1+ gapping (3-5mm) at final follow-up. All patients with persistent laxity, except 1 patient with persistent pain in the setting of a midsubstance tear, reported subjective improvement with only occasional to intermittent pain or mechanical symptoms at final follow-up.
Conclusions:
The majority of conservatively treated high grade, isolated MCL tears will attain adequate healing with resolution of medial joint space gapping. In accordance with previous reports, proximal tears were the most common location of MCL injury in this cohort. The highest proportion of tears with residual laxity at final follow-up were located distally, however this was not statistically significant. While 75% of distal tears healed with persistent medial laxity; in all cases, gapping was 1+ (3-5mm) at time of final follow-up. This small degree of residual laxity is likely clinically acceptable as evidenced by patient reported symptom improvement at corresponding final follow-up.