A High Percentage of Patients With Anterior Cruciate Ligament Tears Treated Nonoperatively Show Persistent Laxity on Arthrometer Assessment Despite Magnetic Resonance Imaging Evidence of Fiber Continuity: A Systematic Review.

PURPOSE: To evaluate magnetic resonance imaging (MRI) findings after nonoperatively treated anterior cruciate ligament (ACL) injuries and to assess objective knee stability using KT-1000/2000 arthrometer readings.

METHODS

A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search of Cochrane, Embase, Scopus, and Medline identified studies assessing ACL healing in nonoperative patients using MRI, arthrometer (KT-1000/2000), or arthroscopic evaluation. Inclusion criteria were: (1) studies that evaluated patients with ACL tears treated nonoperatively, (2) studies that used MRI to assess ACL healing, and (3) human studies published in English. Exclusion criteria were: (1) studies that did not use objective measures to assess ACL healing in nonoperative patients, (2) cadaveric studies, and (3) case reports and conference abstracts. Data extraction included demographics, treatment approaches, imaging findings, arthrometer and arthroscopic results, and patient-reported outcome measures.

RESULTS

Seven studies with 351 patients (mean age: 30.1 years) met inclusion criteria. The studies had a mean follow-up time of 11.3 months (range: 6-30 months). MRI showed ACL fiber continuity in 85.6% (95% confidence interval: 84.5-86.6; standard deviation: 9.7; range: 70-100) of patients at follow-up. However, this did not correlate with clinical findings as arthrometer (KT-1000/2000) readings only revealed ACL stability in 54.7% (95% confidence interval: 53.4-55.9; standard deviation: 24.1; range: 2-85.7) of cases. Patient-reported outcomes showed a relatively good return of knee function, but 21.9% (standard deviation: 3.2; range: 14.3-25.8) of patients eventually underwent delayed anterior cruciate ligament repair. Additionally, 7.1% (standard deviation: 2.9; range: 5.9-14.3) of nonoperative patients experienced a reinjury.

CONCLUSIONS

Although MRI may show continuity of ACL fibers with nonoperative treatment protocols, KT-1000/2000 findings suggest that joint laxity persists.

LEVEL OF EVIDENCE: Level IV, systematic review of Level II to IV studies.