RETURN TO SPORT AFTER ACHILLES TENDON RUPTURE

Background: Achilles tendon (AT) rupture is a common injury, particularly among physically active individuals, with a 30% growth rate in the most affected age group (30–39 years). Among professional athletes, 25% fail to return to sport (RTS), and those who do typically require 8–11 months of recovery. Furthermore, their performance can decline by up to 50% during the two years following RTS, and their career length is shorter compared to non-injured players or those with anterior cruciate ligament (ACL) injuries. Long-term deficits after AT repair have been documented up to 10 years post-injury, including tendon elongation, reduced calf circumference, atrophy of type-1 muscle fibers, decreased heel-raise test performance, and reduced ability to generate force in a plantar-flexed position. Additionally, low psychological readiness to RTS, or high levels of kinesiophobia at six months may influence RTS outcomes. Given these suboptimal RTS outcomes and the lack of consensus on optimal treatment strategies for AT rupture, there is a need to explore potential areas for improvement in the RTS process. Aims: These considerations have inspired my PhD research project, which aims to identify gaps in the current AT RTS process and provide insights to optimize outcomes for patients recovering from AT rupture. The specific aims of the three research projects are as follows: 1. To map the literature regarding which criteria are used to clear athletes for RTS after AT repair. Understanding the criteria defined in the literature allows for clarity on the standards required for RTS and the identification of potential gaps area in the RTS process that lack clear guidelines. 2. To observe and analyze the impact of AT rupture in ankle movement quality during the mid-stage of rehabilitation. The comparison between the repaired and unrepaired limbs aims to identify potential differences in movement quality between the two ankles. 3. To describe the on-field rehabilitation (OFR) workload of football players returning to sport after AT repair. Global Positioning System (GPS) monitoring workloads during the late-stage of rehabilitation may be a key factor to lead load progression during the late-stage of rehabilitation, providing insights to prepare football players for the demands of the return to training (RTT). Methods: 1) Project one involved a Scoping Review conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist. A combination of search terms and Boolean operators, regarding AT rupture and RTS criteria, was used to search the literature from 1995 to 2022 across three databases: Web of Science, Scopus, and MEDLINE. Papers inclusion and exclusion criteria were defined. A data charting was create to collect criteria, and the insights regarding AT rehabilitation outcome. 2) Project two was a case series involving 23 sportive patients who underwent AT repair. The inclusion criteria for participants were: being treated at one of the Isokinetic Medical Group Clinics, having undergone Achilles tendon (AT) repair surgery, and performing a bilateral depth jump. To observe the ankle movement quality the ankle joint angle (γ angle), and peak vertical ground reaction force (peak VGFR), in both repaired and unrepaired limbs during the eccentric and concentric phase of a bilateral depth jump where assessed. To test for differences between the repaired and unrepaired sides, variables were analyzed collectively using a multivariate Mixed Linear Model with repeated measures. Effect sizes and confidence intervals were also computed. 3) Project three was a pilot study with a small cohort including 5 male football players who underwent AT repair and were monitored during the OFR. Workload data for each OFR session were collected using GPS and heart rate tracking. Variables measured and reported were: PL, Player load (Arbitrary Unit-AU); TD, total distance (km); MSR, moderate speed running distance (defined as 15-20 km/h); HSR, high speed running distance (defined as 20-25 km/h); SRT, sprint distance (>25 km/h); MS, max-speed (km/h); ACC, Number of accelerations (>2m/s2); DEC, Number of decelerations (>2m/s2); time in Aerobic zone (70-85% HRmax); time in Anaerobic zone (>85% HRmax). Variations in GPS metrics were calculated as percentages between stages and from stage 1 to stage 5 to identify notable changes. As a follow-up, the ankle ligament reconstruction-return to sport injury (ALR-RSI) score was used to evaluate the footballers psychological readiness to RTS. Main results: 1. In project one, the main result was that none of the 34 included studies explicitly defined any RTS criteria to clear athletes after AT rupture. The literature primarily focused on provide measurements related to the early stage of rehabilitation, while no specific measurements for the mid- and late-stages of rehabilitation were identified. These findings highlight the need to investigate appropriate measurements for evaluating progress during the mid-and late- stage of the rehabilitation process in the context of RTS after AT rupture. 2. In project two, the main findings were: an average ankle joint angle 8 degrees smaller for the limb that underwent AT repair compared to the unrepaired one at IC during the depth jump (p<0.001), and a mean peak VGRF 3.6 N/kg higher for the unrepaired limb at IC (p<0.001). These results suggest changes in ankle movement quality, with a more dorsiflexed repaired ankle and a body weight shift (BWS) towards the unrepaired limb during the landing phase of the jump, while no differences were observed during the concentric phase. Integrating ankle movement quality assessments in the mid-stage of rehabilitation may be a key factor in evaluating ankle impairments and potential shifts in ankle movement patterns with higher peak knee loads in the same limb. 3. In project three the main result was that a notable increase was found for RPE, MSR, HSR, ACC, DEC, aerobic and anaerobic zone from the start to the end of the OFR. These metrics may correlate with improved RTS outcomes and risk of re-injury. Thus, GPS load monitoring data plays a key role in the progress of the football player between OFR stages following AT repair. Additionally, suboptimal outcomes in psychological readiness for RTS may occur post- AT repair. Therefore, although RTS is achievable after AT repair, further research is required to optimize OFR load management and enhance psychological readiness for RTS.