Late-stage rehabilitation effects do not differ between quadriceps and hamstring tendon autograft after anterior cruciate ligament reconstruction: a multicentre propensity score-matchedcase-control intervention trial

Late-stage rehabilitation interventions after an anterior cruciate ligament (ACL) reconstruction are under-researched, inter alia regarding potential differences in rehabilitation effects between autograft types. This study determined the effectiveness of a specific, late-stage rehabilitation to usual care after ACL reconstructions in patients with a quadriceps versus such with a hamstring tendon autograft. In this multicentre case-control intervention study, participants aged 18-35 years were included at the end of their formal rehabilitation (mean 8.1 months) after ACL reconstruction. Twenty-four cases with an arthroscopically assisted, anatomic ipsilateral quadriceps femoris tendon autograft and two numerically equal hamstring tendon reconstructed propensity score-matched groups were compared. Matching variables were gender, age, Tegner activity scale, plus, once, the time since reconstruction and once the functional capacity at intervention onset. All participants performed a 5-month performance enhancing intervention. All outcomes were measured once a month. Self-reported outcomes such as knee function (The Knee injury and Osteoarthritis Outcome Score (KOOS) Sport as the main self-reported outcome) were followed by a series of hop and jump tests. The front hops for distance (outcome: hopping distance) was the primary outcomes of the study. Linear mixed models were calculated using change scores. All participants were analysed. No group*time interaction effect could be identified in the two main outcomes KOOS SPORT and front hop for distance. Furthermore, with the exception of the self-reported all-day function, no outcome displayed any between-group differences in the trainability, either. The return-to-sport success took a mean time of 3.8 months after study commencement; the success rates ranged between 80% and 83% and were not different between groups. Being reconstructed with a hamstrings or with a quadriceps tendon autograft had no impact on the late-stage rehabilitation effects after an ACL rupture. Both graft choices enable comparably favourable functional outcomes and return-to-sport success rates. Conversely, no recommendation can be derived with regard to the selection of either a hamstring or a quadriceps autograft type. The decision must be undertaken individually and based on other factors.