Summary

Isokinetic muscle strength and dynamic postural stability did not fully recover by 6 months after lateral MAT but showed significant improvements by 12 months.

Abstract

Background

Despite numerous studies examining subjective clinical scores after meniscal allograft transplantation (MAT), research focusing specifically on functional measures is lacking.

Purpose

To evaluate the serial changes in isokinetic muscle strength and dynamic balance during the first postoperative year after lateral MAT

Study design: Retrospective comparative

Methods

Fifty-five patients who underwent lateral MAT underwent subjective functional assessment using the Lysholm and subjective International Knee Documentation Committee (IKDC) scores. The objective functions, evaluated using isokinetic muscle strength testing and the Y-balance test for dynamic postural stability, were recorded preoperatively and 6 and 12 months postoperatively. Magnetic resonance imaging (MRI) was performed at 2 days and 12 months postoperatively to evaluate meniscal allograft extrusion and cartilage condition in the lateral compartment. At 12 months, patients with graft extrusion > 3 mm on MRI were assigned to the extrusion group.

Results

Significant improvements were observed in the Lysholm and subjective IKDC scores at 12 months postoperatively (both p < 0.001). The joint space width showed a nonsignificant increase (p = 0.054). Coronal graft extrusion increased significantly (p < 0.001). At 6 months postoperatively, isokinetic muscle strength tests indicated a slight, nonsignificant reduction in the peak torque for knee extension (p = 0.911). However, at 12 months, the peak torque was significantly increased (p = 0.001), with the deficits improving from 38.3% to 18.1% (p < 0.001). No significant changes were noted in the knee flexion strength. Dynamic postural stability showed a significant decrease in the Limb Symmetry Index (LSI) for the anterior reach at 6 months (p = 0.004), but significant improvements were seen by 12 months, with LSI for the anterior, posteromedial, and posterolateral reaches all exceeding 90% (p < 0.001). No significant differences in muscle strength or dynamic balance were found between the non-extrusion (n = 41) and extrusion (n = 14) groups at 12 months.

Conclusion

Isokinetic muscle strength and dynamic postural stability reached levels comparable with those of the uninvolved knee 12 months after lateral MAT, highlighting the importance of a 12-month rehabilitation period for optimal recovery and the need for caution against early sports resumption.