Etiology, Diagnosis and Treatment of Tendinous Knee Extensor Mechanism Injuries.

Abstract

Quadriceps and patella tendon ruptures are uncommon injuries often resulting from minor trauma typically consisting of an eccentric contraction of the quadriceps muscle. Since rupture of a healthy tendon is very rare, such injuries usually represent the end stage of a long process of chronic tendon degeneration and overuse. This review aims to give an overview of the current understanding of the pathophysiology, diagnostic principles, and recommended treatment protocols as supported by the literature and institutional experience. A non-systematic review of the current literature on the subject was conducted and reflected against the current practice in our level 1 trauma center. Risk factors for patella and quadriceps tendon rupture include increasing age, repetitive micro-trauma, genetic predisposition, and systemic diseases, as well as certain medications. Diagnosis is based on history and clinical findings, but can be complemented by ultrasound or magnetic resonance imaging. Accurate diagnosis at an early stage is of utmost importance since delay in surgical repair of over 3 weeks results in significantly poorer outcomes. Operative treatment of acute ruptures yields good clinical results with low complication rates. Use of longitudinal transpatellar drill holes is the operative method of choice in the majority of acute cases. In chronic ruptures, tendon augmentation with auto- or allograft should be considered. Postoperative treatment protocols in the literature range from early mobilization with full weight bearing to cast immobilization for up to 12 weeks. Respecting the biology of tendon healing, we advocate the use of a removable knee splint or orthotic with protected full weight bearing and limited passive mobilization for 6 weeks.