Trunk Biomechanics in Individuals with Knee Disorders: A Systematic Review with Evidence Gap Map and Meta-analysis

Abstract

Background: The trunk is the foundation for transfer and dissipation of forces throughout the lower extremity kinetic chain. Individuals with knee disorders may employ trunk biomechanical adaptations to accommodate forces at the knee or compensate for muscle weakness. This systematic review aimed to synthesize the literature comparing trunk biomechanics between individuals with knee disorders and injury-free controls.

Methods: Five databases were searched from inception to January 2022. Observational studies comparing trunk kinematics or kinetics during weight-bearing tasks (e.g., stair negotiation, walking, running, landings) between individuals with knee disorders and controls were included. Meta-analyses for each knee disorder were performed. Outcome-level certainty was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE), and evidence gap maps were created.

Results: A total of 81 studies investigating trunk biomechanics across six different knee disorders were included (i.e., knee osteoarthritis [OA], total knee arthroplasty [TKA], patellofemoral pain [PFP], patellar tendinopathy [PT], anterior cruciate ligament deficiency [ACLD], and anterior cruciate ligament reconstruction [ACLR]). Individuals with knee OA presented greater trunk flexion during squatting (SMD 0.88, 95% CI 0.58-1.18) and stepping tasks (SMD 0.56, 95% CI 0.13-.99); ipsilateral and contralateral trunk lean during walking (SMD 1.36; 95% CI 0.60-2.11) and sit-to-stand (SMD 1.49; 95% CI 0.90-2.08), respectively. Greater trunk flexion during landing tasks in individuals with PFP (SMD 0.56; 95% CI 0.01-1.12) or ACLR (SMD 0.48; 95% CI 0.21-.75) and greater ipsilateral trunk lean during single-leg squat in individuals with PFP (SMD 1.01; 95% CI 0.33-1.70) were also identified. No alterations in trunk kinematics of individuals with TKA were identified. Evidence gap maps outlined the lack of investigations for individuals with PT or ACLD, as well as for trunk kinetics across knee disorders.

Conclusion: Individuals with knee OA, PFP, or ACLR present with altered trunk kinematics in the sagittal and frontal planes. The findings of this review support the assessment of trunk biomechanics in these individuals in order to identify possible targets for rehabilitation and avoidance strategies.

Trial registration: PROSPERO registration number: CRD42019129257.

Keywords: Anterior cruciate ligament; Knee injuries; Knee pain; Knee surgeries; Trunk motion.

Fig. 1

Flow diagram of search results. CINAHL Cumulative Index to Nursing and Allied Health Literature

Fig. 2

Meta-analyses of trunk kinematics in individuals with knee OA compared to controls. Trunk kinematics in the sagittal plane during walking (A), sit-to-stand (B), and stepping tasks (C). Trunk kinematics in the frontal plane during walking (D) and sit-to-stand (E). Trunk kinematics in the transverse plane during walking (F). (1) varus OA group, (2) valgus OA group, (3) mild OA group, (4) moderate OA group, (5) C-TST OA group, (6) IC-STS OA, (7) SI-STS OA group, (8) less severe OA group, (9) more severe OA group, (10) group with unilateral pain and radiographic knee OA, (11) group with unilateral pain and bilateral radiographic knee OA, (12) group with bilateral pain and radiographic knee OA, (13) mild OA group, (14) moderate OA group, (15) severe OA group, (16) group with unilateral OA pain, (17) group with bilateral OA pain. HQ high quality, MQ moderate quality, OA osteoarthritis, KL Kellgren–Lawrence grade. ^† Groups divided considering different magnitudes of compensation strategies while performing the task

Fig. 3

Meta-analyses of trunk kinematics in individuals with TKA compared to controls. Trunk kinematics in the sagittal plane during walking (A) and stepping tasks (B). Trunk kinematics in the frontal plane during walking (C) and stepping tasks (D). Trunk kinematics in the transverse plane during walking (E) and stepping tasks (F). TKA Total knee arthroplasty, MQ moderate quality

Fig. 4

Meta-analyses of trunk kinematics and strength in individuals with PFP compared to controls. Trunk kinematics in the sagittal plane during running (A), stepping (B), and landing tasks (C). Trunk kinematics in the frontal plane during running (D), squatting (E), stepping (F), and landing tasks (G). Trunk kinematics in the transverse plane during landing tasks (H). (1) PFP and control groups with knee crepitus, PFP and control groups without knee crepitus, (3) PFP group with elevated fear avoidance beliefs, (4) PFP group with low fear avoidance beliefs. PFP patellofemoral pain, HQ high quality, MQ moderate quality, SLH single-leg hop for distance, SLS single-leg squat, FSD forward step-down. ^‡Data supplied by author

Fig. 5

Meta-analyses of trunk kinematics in individuals with ACLR compared to controls. Trunk kinematics in the sagittal plane during landing (A) and jumping (B) tasks. Trunk kinematics in the frontal plane during landing tasks (C). (1) ACLR group with high fear of reinjury, (2) ACLR group with low fear of reinjury. ACLR anterior cruciate ligament reconstruction, HQ high quality, LQ low quality, MQ moderate quality, BDJ bilateral drop jump, DVJ drop vertical jump, SLDJ single-leg drop jump, SLH single-leg hop for distance, SLVJ single-leg vertical jump, VCJ single-leg vertical countermovement jump