Studies on meniscus surgery with focus on preservation and meniscus function

Abstract: The aim of this thesis was to investigate the effect of surgical preservation and restoration of the meniscus on knee function and outcomes. In Study I, 4497 patients with primary hamstring ACLR were evaluated regarding knee laxity preoperatively and at 6-months follow-up using KT-1000. The primary aim was to evaluate the ATT depending on type of treatment of meniscus injuries in conjunction to primary ACLR. A significant reduction in laxity was found for all patients. Medial meniscus resection resulted in significantly increased laxity compared to isolated ACLR. Medial meniscus repair resulted in laxity comparable to isolated ACLR. In Study II, all ACLRs from the SNKLR were evaluated. The primary aim was to compare KOOS and EQ-5D at 2-year follow-up after isolated ACLR to ACLR with associated meniscus injury treated with either repair or resection in the Swedish National Knee Ligament Register. Meniscus resection resulted in worse outcome, whereas meniscus repair resulted in comparable outcome to isolated ACLR. In Study III, 918 meniscus repairs were analysed. The primary aim was to assess failure within three years. Repair with arrows and medial repairs resulted in significantly more failures than repair with anchors and lateral repairs. Concomitant ACLR resulted in less failure of meniscus repair than isolated meniscus repairs. In Study IV, 316 consecutive meniscus repairs were followed up with radiology, KOOS and Lysholm. The primary aim was to determine the effect of meniscus repair on OA and secondly its effect on subjective knee function. Failed meniscus repair resulted in significantly higher risk for OA and worse patient reported outcome. In Study V, seven cases of meniscus transplantation using the semitendinosus tendon are described. The surgical technique is described in detail. Four patients had completed the 12- month follow-up and report significantly improved outcome in IKDC Global Score, KOOS pain subscale and Lysholm. In conclusion, meniscus repair result in less OA and better subjective knee function than meniscus resection. Medial meniscus repair provides less knee laxity than meniscus resection. Failure after meniscus repair are more common for medial and isolated repairs. In cases of post meniscectomy symptoms, the semitendinosus tendon could possibly function as a meniscus transplant with improved knee function for the patients.