Effect of Preoperative Joint Space Width on Lateral Meniscal Allograft Transplantation: Outcomes at Midterm Follow-up.

Background: It remains unclear whether lateral joint space narrowing without severe cartilage loss before meniscal allograft transplantation (MAT) affects clinical outcomes and graft extrusion. Hypothesis: Patients with greater preoperative joint space narrowing would show more graft extrusion, more osteoarthritis progression, and worse clinical outcomes than would those with less narrowing. Study Design: Case-control study; Level of evidence, 3. Methods: We retrospectively evaluated 61 patients who underwent lateral MAT and had a minimum follow-up of 4 to 5 years. The median preoperative joint space width (JSW) on Rosenberg view radiographs was used to classify patients into those with less joint space narrowing (JSW ≥3 mm; group A) and greater joint space narrowing (JSW <3 mm; group B). We compared differences between groups in terms of graft extrusion and articular cartilage loss (modified Outerbridge grade ≥3) on 1-year postoperative magnetic resonance imaging (MRI) scans and changes in JSW and clinical outcomes at the last follow-up. Results: There were 31 patients in group A and 30 patients in group B; the mean follow-up time for all patients was 64.4 ± 10.3 months. All patients showed a significant preoperative to postoperative improvement in outcome scores ( Conclusion: Patients with less preoperative joint space narrowing had less graft extrusion and cartilage loss on 1-year postoperative MRI scans, as well as better radiological and clinical outcomes at midterm follow-up, compared with patients with greater preoperative narrowing.