Purpose: To evaluate the clinical outcomes of a new arthroscopic procedure, arthroscopic posteromedial release (PMR), and its potential use as a treatment option for medial-type osteoarthritic (OA) knees.
Type of study: Retrospective analysis of clinical outcomes of a case series.
Methods: Knees with medial-type OA and flexion contracture were treated with PMR. They were classified using the Kellgren and Lawrence (K/L) radiographic grading system and classified using magnetic resonance imaging (MRI) into smooth (S) or irregular (IR) groups, based on the subchondral contour of the medial femoral condyle. Clinical outcome was evaluated using the Japanese Orthopaedic Association knee score (JOA score), verbal rating scale (VRS), and patient satisfaction.
Results: Fifty-two patients with 58 OA knees were included in the study. The mean age of the patients at the time of surgery was 71.6 years, the average ROM was from 13 degrees to 129 degrees , and the average follow-up period was 3.3 years. Most of the knees were classified as K/L grade III or IV. Overall, the average JOA score improved to 71.6 points from 56.3 points preoperatively. VRS scores decreased in most patients, and 76% of patients were satisfied at their last follow-up. The JOA score of the K/L grade III knees improved to 76.9 from 60.4 points preoperatively and that of the K/L grade IV knees improved to 69.5 from 55.3 points. The improvement in JOA score was less for the IR group, from 54.5 to 66.2 points, than for the S group, from 62.3 to 79.6 points. Five knees from the IR group and 1 from the S group were converted to total knee arthroplasty.
Conclusions: Knees with relatively advanced OA, for which arthroscopic debridement has conventionally been contraindicated, can be treated with PMR if they are selected properly based on MRI findings.
Level of evidence: Level IV, case series.