There is more to the knee joint than just the quadriceps: A systematic review with meta-analysis and evidence gap map of hamstring strength, flexibility, and morphology in individuals with gradual-onset knee disorders.

BACKGROUND: Impairments in hamstring strength, flexibility, and morphology have been associated with altered knee biomechanics, pain, and function. Determining the presence of these impairments in individuals with gradual-onset knee disorders is important and may indicate targets for assessment and rehabilitation. This systematic review aimed to synthesize the literature to determine the presence of impairments in hamstring strength, flexibility, and morphology in individuals with gradual-onset knee disorders. METHODS: Five databases ((MEDLINE, Embase, CINAHL, SPORTDiscus, and Web of Science) were searched from inception to September 2022. Only studies comparing hamstring outcomes (e.g., strength, flexibility, and/or morphology) between individuals with gradual-onset knee disorders and their unaffected limbs or pain-free 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, and evidence gap maps were created. RESULTS: Seventy-nine studies across 4 different gradual-onset knee disorders (i.e., knee osteoarthritis (OA), patellofemoral pain (PFP), chondromalacia patellae, and patellar tendinopathy) were included. Individuals with knee OA presented with reduced hamstring strength compared to pain-free controls during isometric (standard mean difference (SMD) = -0.76, 95% confidence interval (95%CI) : -1.32 to -0.21) and concentric contractions (SMD = -0.97, 95%CI : -1.49 to -0.45). Individuals with PFP presented with reduced hamstring strength compared to pain-free controls during isometric (SMD = -0.48, 95%CI : -0.82 to -0.14), concentric (SMD = -1.07, 95%CI : -2.08 to -0.06), and eccentric contractions (SMD = -0.59, 95%CI : -0.97 to -0.21). No differences were observed in individuals with patellar tendinopathy. Individuals with PFP presented with reduced hamstring flexibility when compared to pain-free controls (SMD = -0.76, 95%CI : -1.15 to -0.36). Evidence gap maps identified insufficient evidence for chondromalacia patellae and hamstring morphology across all gradual-onset knee disorders. CONCLUSION: Our findings suggest that assessing and targeting impairments in hamstring strength and flexibility during rehabilitation may be recommended for individuals with knee OA or PFP.

Two Weeks of Wearing a Knee Brace Compared With Minimal Intervention on Kinesiophobia at 2 and 6 Weeks in People With Patellofemoral Pain: A Randomized Controlled Trial.

OBJECTIVE: To investigate the effect of a knee brace compared with minimal intervention on self-reported kinesiophobia and function, objective function, and physical activity level in people with patellofemoral pain (PFP). DESIGN: Single-blind randomized controlled trial (1:1), parallel. PARTICIPANTS: Individuals with PFP (N=50). MAIN OUTCOME MEASURES: Primary: kinesiophobia (Tampa Scale for Kinesiophobia). Secondary: self-reported function (Anterior Knee Pain Scale), physical activity level (International Physical Activity Questionnaire), and objective function (forward step-down test). Outcomes were assessed at baseline (T0), at the end of the intervention (2wk) (T1), and at 6 weeks after baseline (T2). INTERVENTION: Participants were randomly assigned to 1 of 2 interventions groups: (1) use of knee brace for 2 weeks during daily living, sports, or painful tasks (brace group) and (2) educational leaflet with information about PFP (leaflet group). RESULTS: The knee brace reduced kinesiophobia in people with PFP compared with minimal intervention with moderate effect size at T1=mean difference (95% CI) -5.56 (-9.18 to -1.93) and T2=-5.24 (-8.58 to -1.89). There was no significant difference in self-reported and objective function and physical activity level. CONCLUSIONS: The knee brace improved kinesiophobia immediately after intervention (at 2wk) and at 6-week follow-up in people with PFP compared with minimal intervention. A knee brace may be considered within clinically reasoned paradigms to facilitate exercise therapy interventions for people with PFP.

Influence of kinesiophobia and pain catastrophism on objective function in women with patellofemoral pain.

OBJECTIVES: (i) To compare kinesiophobia, pain catastrophism and objective function between women with patellofemoral pain (PFP) and pain-free; (ii) to investigate the association of kinesiophobia and pain catastrophism with objetive function in women with PFP. DESIGN: Case-control. SETTING: Laboratory-based. PARTICIPANTS: Fifty-five women with PFP and forty pain-free women. MAIN OUTCOME MEASURES: Kinesiophobia and pain catastrophism were assessed using the Tampa Scale of Kinesiophobia and Pain Catastrophizing Scale, respectively. Forward step-down, single leg hop, and modified star balance tests were used to assess objective function. Independent t-tests were used for between-groups comparisons and Pearson correlation coefficients were used to investigate the association between the outcomes. RESULTS: Women with PFP had significantly worse kinesiophobia (p < 0.001; Effect size (ES) = 1.16), pain catastrophism (p < 0.001; ES = 1.57), and poorer objective function (step-down, (p < 0.001; ES = 0.99); single-leg hop (p = 0.002; ES = 0.74); modified star balance (p < 0.001; ES = 0.66) than pain-free controls. Kinesiophobia and pain catastrophism were not correlated with objective function. CONCLUSION: Greater kinesiophobia, pain catastrophism and poorer objective function is evident in women with PFP, compared to pain-free controls. Kinesiophobia and pain catastrophism were not associated with objective function in women with PFP. Future research is necessary to understand how other physical and psychological factors might affect objective function.