Abstract
PurposeTo determine how concomitant medial collateral ligament (MCL) and lateral collateral ligament (LCL) injuries affect outcome after anterior cruciate ligament (ACL) reconstruction.MethodsPatients aged > 15 years who were registered in the Swedish National Knee Ligament Registry for primary ACL reconstruction between 2005 and 2016 were eligible for inclusion. Patients with a concomitant MCL or LCL injury were stratified according to collateral ligament treatment (non-surgical, repair or reconstruction), and one isolated ACL reconstruction group was created. The outcomes were ACL revision and the 2-year Knee Injury and Osteoarthritis Outcome Score (KOOS), which were analyzed using univariable and multivariable Cox regression and an analysis of covariance, respectively.ResultsA total of 19,457 patients (mean age 27.9 years, 59.4% males) met the inclusion criteria. An isolated ACL reconstruction implied a lower risk of ACL revision compared with presence of a non-surgically treated MCL injury (HR = 0.61 [95% CI 0.41–0.89], p = 0.0097) but not compared with MCL repair or reconstruction. A concomitant LCL injury did not impact the risk of ACL revision. Patients with a concomitant MCL or LCL injury reported inferior 2-year KOOS compared with isolated ACL reconstruction. The largest difference was found in the sports and recreation subscale across all groups, with MCL reconstruction resulting in the maximum difference (14.1 points [95% CI 4.3–23.9], p = 0.005).ConclusionNon-surgical treatment of a concomitant MCL injury in the setting of an ACL reconstruction may increase the risk of ACL revision. However, surgical treatment of the MCL injury was associated with a worse two-year patient-reported knee function. A concomitant LCL injury does not impact the risk of ACL revision compared with an isolated ACL reconstruction.Level of evidenceCohort study, Level III.
Highlights
The medial collateral ligament (MCL) and the lateral collateral ligament (LCL) of the knee joint are primary restraints to valgus and varus forces, respectively, and do counteract tibial rotation [11, 30]
The risk of anterior cruciate ligament (ACL) revision was significantly increased for patients undergoing ACL reconstruction and non-surgical treatment of their concomitant MCL injury, while patients treated with either MCL suture repair or reconstruction did not display an increased risk of ACL revision compared with isolated ACL reconstruction
This study showed that the 2-year Knee Injury and Osteoarthritis Outcome Score (KOOS) was significantly lower across all study groups in patients with a concomitant MCL injury compared with the isolated ACL injury group
Summary
The medial collateral ligament (MCL) and the lateral collateral ligament (LCL) of the knee joint are primary restraints to valgus and varus forces, respectively, and do counteract tibial rotation [11, 30]. The shared stabilizing properties of the collateral ligaments and the anterior cruciate ligament (ACL) mean that the risk of combined injuries to these structures is high. Consensus has not yet been reached in terms of the optimal treatment for combined injuries and there is sparse evidence relating to the way the presence and treatment of concomitant collateral ligament injuries affect the outcome after primary ACL reconstruction. MCL deficiency has been reported to increase the forces on the ACL graft [1, 43] and surgical intervention to re-establish the stabilizing properties of the MCL may benefit the healing of both the ACL graft and the MCL [37]. Several techniques for the surgical treatment of the MCL, involving both suture repair and ligament reconstruction, have been described and reported to produce successful outcomes [2, 4, 5, 9, 21, 26, 42]
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