Arthroscopy - 2026-09-18 - Journal Article
Lack of Knee Confidence Is Associated With Lower Functional Scores After Anterior Cruciate Ligament Reconstruction at 2-Year Follow-Up.
Smith AR, Mazzocca JL, Wang M, Gordon OL, Chang Y, Katz JN, Matzkin EG
Topics
Key Takeaway
At 2-year follow-up after ACLR, patients lacking knee confidence had significantly lower Marx Activity Rating Scale scores (4.7 vs 8.9) and KOOS Sport/Rec scores (58.1 vs 85.7) compared to confident patients, with MCID achievement rates of 70.6% vs 91.2%.
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Summary
This retrospective cohort examined the trajectory of knee confidence using KOOS Q41 from preoperative baseline through 2-year follow-up in 165 primary hamstring auto- or allograft ACLR patients, and correlated confidence status with functional outcomes. Lack of knee confidence declined from 88.5% preoperatively to 24.2% at 2 years. Patients still lacking confidence at 2 years had markedly lower Marx (4.7 vs 8.9) and KOOS Sport/Rec (58.1 vs 85.7) scores and were less likely to achieve MCID (70.6% vs 91.2%, P=.002); age, sex, and graft type did not predict confidence at any timepoint.
Key Limitation
The retrospective design with exclusion of patients missing KOOS Q41 at any timepoint introduces selection bias, as patients lost to follow-up or with incomplete data may disproportionately represent those with poor confidence or worse outcomes.
Original Abstract
PURPOSE
To evaluate how patients rate their knee confidence after anterior cruciate ligament injury, when confidence in their knee returns after anterior cruciate ligament reconstruction (ACLR), and how knee confidence correlates with self-reported outcomes related to return to sport and activity.
METHODS
A retrospective analysis was done on a consecutive cohort of patients who underwent a primary ACLR with hamstring auto- and allograft between October 2012 and August 2022 with a minimum 2-year follow-up. Patients who had a concomitant ligament surgery, revision ACLR, quadriceps or bone-patellar tendon-bone autograft, concurrent osteotomy, or were missing Knee Injury and Osteoarthritis Outcome Score Question #41("How much are you troubled with lack of confidence in your knee?") at any timepoint were excluded. Patients were considered as lacking knee confidence if they answered "Moderately," "Severely," or "Extremely." The trend of lack of knee confidence from preoperative to 2-year postoperative timepoints was examined, and the associations between the lack of confidence and the Knee Injury and Osteoarthritis Outcome Score Sports/Rec subscale as well as the Marx Activity Rating Scale were explored.
RESULTS
A total of 165 patients met the inclusion criteria. Preoperatively, 88.5% of patients expressed a lack of confidence in their knees. This percentage declined, reaching 24.2% at 2 years post-ACLR. Age, sex, and graft type were not associated with knee confidence at any timepoint. Additionally, patients who expressed lack of knee confidence at 2 years postoperatively had significantly lower Marx Activity Rating Scale (4.7 vs 8.9, P < .001) and Knee Injury and Osteoarthritis Outcome Score Sport/Rec scores (58.1 vs 85.7, P < .001) and were less likely to have achieved minimal clinically important difference (70.6% vs 91.2%, P = .002) compared with those with confidence at 2 years postoperatively.
CONCLUSIONS
This study shows improvement in knee confidence post-ACLR with factors such as sex, age, graft type, and size having no notable impact. Lack of knee confidence correlates with lower functional scores at 2 years post-ACLR.
LEVEL OF EVIDENCE
Level III, retrospective comparative case series.