Objective: Total replacement of the meniscus to reduce pain and improve joint function.
Indications: Symptomatic early arthrosis of the lateral compartment in young patients after loss of the lateral meniscus. Loss of the medial meniscus and anterior knee instability in young, active patients.
Contraindications: Advanced cartilaginous damage. Malalignment of the longitudinal axis. Knee ligament instability.
Surgical technique: Preparation of the allogenic meniscal transplant. Placement of sutures to the "horn ligaments". Lateral or medial arthrotomy. Osteotomy of the femoral epicondyle with the collateral ligament. Excision of meniscal residues leaving only a narrow outer rim. Holes are drilled from the anterolateral or anteromedial tibial metaphysis to the horn insertions. The horn ligaments are pulled into the drill holes. Fixation of the meniscal transplant by insertion of vertical sutures at the outer rim and joint capsule. Tightening and temporary fixation of the meniscal horn sutures at the exit sites of the drill holes. The function of the transplanted meniscus is evaluated, the tension in the sutures adjusted as required and, finally, the ends are knotted. Refixation of the epicondyle with a 6.5-mm cancellous bone screw.
Postoperative management: Active and passive exercises from extension to 90 degrees flexion. Partial loading in a brace in extension on two crutches for the first 6 weeks postoperatively. No full squat for a further 3 months. Sports activities not before the end of the 1st postoperative year.
Results: Good results for correct indications with a survival rate of the transplant of 70-80% after 3-7 years and significant improvement of joint function and pain reduction. An effect on the results related to arthroscopically assisted or open technique and/or related to anchorage of the meniscal horns in the bone or soft tissue could not be shown. In biomechanical terms, the stable fixation of the meniscal horns is decisive. Fixation of the periphery of the meniscus to the joint capsule by vertical sutures alone is not sufficient but does play an important role in the incorporation of the meniscal tissue. Anterior cruciate ligament reconstruction should be performed at the same time; correction osteotomy should be performed at a separate operation prior to meniscal allograft transplantation.