Midterm Outcomes After Meniscal Allograft Transplantation: Comparison of Cases With Extrusion Versus Without Extrusion.

Background: Although graft extrusion is of concern after meniscal allograft transplantation (MAT), the correlation between extrusion and clinicoradiological outcomes remains unclear. Hypothesis: Patients with graft extrusion after MAT have worse clinical outcomes and greater arthritic change than those without graft extrusion. Study Design: Cohort study; Level of evidence, 3. Methods: Forty-three patients underwent MAT between 1999 and 2004. Grafts were classified as either nonextruded (<3 mm) or extruded (≥3 mm) according to 1-year postoperative magnetic resonance imaging (MRI) findings. The mean patient age at the time of surgery was 33.5 years (range, 17-43 years), and themean follow-up period was 5.1 years (range, 3.5-8.3 years). The Lysholm score was used to evaluate knee function. In addition, preoperative and postoperative (final follow-up) measurements were taken to determine the absolute and relative (affected side/normal side) joint space width (JSW) on a standing 45° flexion posteroanterior view. Results: Magnetic resonance imaging at 1 year showed the mean graft subluxation was 3.03±0.872 mm across all patients. Twenty-six knees (60%) were classified as nonextruded and 17 (40%) as extruded. No statistical difference was found between these 2 groups regarding Lysholm score improvement after MAT. Overall, absolute and relative JSWs were slightly narrower postoperatively compared with preoperatively across all patients (mean absolute difference, 0.283 mm; mean relative difference; 4.79%; P<.001). However, extruded and nonextruded knees were similar in terms of absolute (P = .764) and relative (P = .482) JSW after MAT. The amount of extrusion did not correlate with Lysholm score or the relative difference between preoperative and postoperative JSW across all patients or in either group. Conclusion: Joint space width was slightly narrower after MAT. Extrusion had no effect on 5-year clinical or radiological outcomes. [ABSTRACT FROM AUTHOR]