Meniscal allograft transplantation improves patient reported outcomes in moderate knee osteoarthritis at 2 years postoperatively

Understanding of the importance of the meniscus for knee joint biomechanics and biology has changed during the last 5 decades.

Anni Aavikko et al conducted a prospective follow-up study to explore meniscal allograft transplantation (MAT) survivorship and patient satisfaction among young patients with symptomatic meniscal deficiency and radiological OA of different Kellgren– Lawrence (K–L) grades.

Thirty-five consecutive MAT patients were prospectively followed up for 2 years. The lateral meniscus was replaced in 29 patients and the medial meniscus in 6 patients. Outcomes were assessed using the KOOS4 composite score, KOOS subscales, Lysholm knee score, and OA K–L grade progression from weight-bearing knee radiographs. For the outcome analysis, patients were categorized into two groups: 19 in Group A (K–L classification 0–1) and 16 in Group B (K–L classification).

Key findings of the study were:

• No bilateral transplantations were performed.

• As a concomitant procedure to MAT, distal femoral osteotomy (DFO) was per formed for 6 patients (17%), high tibial osteotomy (HTO) for one patient (3%), revision ACL surgery for 6 patients (17%), and microfracture of local ICRS grade 4 cartilage lesions for 8 patients (3, tibia condyle; 2, femur condyle; and 3, trochlea). In five of these patients (14%) microfracturing was the only concomitant procedure, while the three others underwent both DFO and microfracturing.

• In terms of KOOS4 and Lysholm scores, the patients showed a clinically significant improvement from baseline to the 1-year follow-up (22.2 points, 95% CI 16.6–27.8 for KOOS4 and 16.8 points, 95% CI 8.9–24.6 for Lysholm), and the improvement remained at 2 years (20.6 points, 95% CI 13.2–28.1 for KOOS4 and 21.5, 95% CI 12.5–30.7 for Lysholm). At the 6-month follow-up, this improvement was not yet observed.

• Minor between-group differences were observed in the KOOS4 and Lysholm scores for the K–L 0–1 and K–L 2 OA groups, but the estimates were imprecise with wide confidence intervals.

• A clinically relevant difference between these two study groups could not be found at any timepoint.

• The reoperation rate was higher in the K–L 2 group than in the K–L 0–1 group (31% vs. 11%).

“MAT yielded improved patient-reported outcomes and subjective satisfaction at 1 and 2 years postoperatively. The differences from baseline exceeded the minimal clinically important difference (MCID) at all timepoints. The severity of cartilage damage and knee OA in terms of the K–L grade at the time of surgery did not affect the KOOS and Lysholm scores after the MAT procedure. Knee OA progression in terms of K–L grade worsening was not observed in any patients” the authors concluded.

Level of evidence III. 

Further reading:

Meniscal allograft transplantation improves patient reported outcomes in both minimal and moderate knee osteoarthritis at 1 and 2 years postoperatively, Anni Aavikko, Ville Bister et al, Knee Surgery, Sports Traumatology, Arthroscopy https://doi.org/10.1007/s00167-023-07625-3