Impact of Hamstring Tendon Graft on Hamstring Length Shortening and Its Influence on Post-Rehabilitation Functional Recovery After ACL Reconstruction: A Case Report

Introduction

Anterior cruciate ligament (ACL) reconstruction is among the most common surgical procedures performed in sports medicine to restore knee stability and functional performance after ligament rupture [1, 2]. The hamstring tendon autograft is widely used because it provides strong fixation, fewer anterior knee complications, and good long-term outcomes compared with patellar tendon grafts [3, 4]. However, the harvest of the semitendinosus and gracilis tendons creates donor site deficits that can influence postoperative recovery [5, 6].

Several studies have demonstrated loss of hamstring muscle length, reduced fascicle size, and decreased strength following tendon harvest [7-9]. The incomplete regeneration of the harvested tendons can lead to shortening of the hamstring muscle–tendon unit, altering its length-tension relationship and affecting functional performance [10, 11]. This shortening is often not specifically evaluated or addressed during rehabilitation. When progressive eccentric lengthening exercises are omitted, persistent tightness and reduced force generation may occur, resulting in asymmetry and poor return-to-sport outcomes [12-14].

Functional strength asymmetry after ACL reconstruction has been strongly associated with lower-limb kinetic imbalances, impaired power restoration, and increased risk of secondary injuries [15-17]. In particular, chronic hamstring tightness and strength deficits can produce compensatory loading on the ankle and hip, predisposing athletes to distal kinetic-chain problems [18, 19].

The present case report highlights how hamstring tendon graft harvesting and the lack of targeted length-restoration rehabilitation contributed to persistent functional deficits and distal joint overload in a recreational football player. The case proposes that tendon shortening secondary to graft harvesting can be a significant yet under-recognized contributor to post-rehabilitation functional limitations, emphasizing the need for individualized follow-up and eccentric lengthening based rehabilitation strategies [20].