Abstract
Background:
Meniscal injury often presents either as part of initial ACL injury or emerges secondarily due to chronic ACL deficiency. Meniscal injuries can be painful, impair function, and lead to joint overload, degeneration, and even early knee osteoarthritis. Meniscus injuries can impact joint load absorption, potentially leading to different landing strategies. In the adult population, ten months after surgery there are no differences in jump performance between patients with concomitant meniscus and ACL injury and isolated ACL injury(1). However, the impact of concomitant injury on jumping strategies and whether it is replicated in adolescent patients is still unclear.
Hypothesis:
Considering that young females are among the highest risk for poor landing mechanics and associated ACL injury, we hypothesized that jump outcomes differ between female patients who had a concomitant meniscus injury versus an isolated ACL injury after they were cleared post-operatively to return to activity (RTA).
Methods:
We conducted a cross-sectional analysis of 30 female adolescent patients who underwent ACL reconstruction surgery (ACLR) classified into two groups: concomitant (meniscus and ACL injuries) or isolated group (ACL-only injury). All participants were released by the attending surgeon to return to activity and completed testing including five trials of countermovement jump on two force plates. The outcomes measured were peak ground reaction force (GRFp) and impulse during propulsion phase, GRFp and absorption rate (GRFp/time to peak) during the landing phase, and jump height. Outcomes were normalized to the participant's body weight or height. Mann-Whitney U, Independent t-tests, or chi-square tests were used to compare groups for demographic characteristics. A MANOVA was used to identify the difference between groups.
Results:
Seventy-seven percent of the patients presented a concomitant meniscus and ACL injury. There was no difference between groups for demographic characteristics, autograft type, or time since surgery (Table 1). The concomitant injury group presented lower GRFp and higher time to GRFp in the injured leg than the isolated injury group (Figure 1A-B). The absorption rate was lower in both legs for the concomitant injury group (Figure 1C-D).
Conclusion:
Female adolescent patients with a concomitant meniscus and ACL injury present a worse strategy in jump landing than those with isolated ACL injury 9 months post-ACLR. Concomitant injury leads to longer landing compensations, which suggests a protective mechanism in favour of the injured leg. Therefore, the rehabilitation process and RTA clearance may take longer and require special attention to the landing strategy for patients who have undergone surgery for concomitant injuries.
