Intercondylar notch stenosis in degenerative arthritis of the knee

Purpose: To present a classification of intercondylar notch stenosis (IS) adjacent to the anterior cruciate ligament (ACL) in degenerative knee arthritis, to raise awareness of this disorder, to describe the arthroscopic findings, and to promote an organized approach to its treatment with favorable results. Type of study: Case series. Methods: Of 362 arthroscopies in patients with gonarthrosis, we identified 122 knees in 96 patients (34%) with central knee pain and subjective instability without ACL laxity to determine the notch changes adjacent to the ACL. We followed a cohort of 69 knees in 64 patients, 47 female (73%) and 17 male (27%), excluding 53 knees in 32 patients for other symptomatic lesions, noncompliance with protocol, or loss to follow-up. The average patient age was 66 years (range, 53 to 78 years). Stenosis was classified as: type I, anterior; type II, lateral; type III, mixed; and type IV, massive. Diagnosis was determined by manipulation during arthroscopy to visualize impingement and was followed by notchplasty. Average follow-up was 26 months (range, 12 to 36 months). Results: Type III was most common, appearing in 48% of knees. Type I was found in 29%, type II in 20%, and type IV in 3% of knees. Preoperatively, central pain occurred in all patients, being moderate in 40 knees (58%) and severe in 26 knees (38%), with diminished strength and subjective instability in all cases; only 42 (61%) had knee extension loss. Flexion contracture resolved in 81% of cases; 90% had good to excellent pain relief and 74% excellent relief of subjective instability, without significant complications. Conclusions: Intercondylar notch stenosis in the arthritic knee may be a cause of ACL damage, symptomatic instability, and loss of extension. A structured approach to diagnosis and treatment was beneficial in restoring more normal function for our patients and may prevent disease progression. Level of evidence: Level IV.