The association between kinesiophobia and functional limitations in service members with knee pain.

BACKGROUND: Knee diagnoses account for more than 50% of lower extremity musculoskeletal conditions in non-deployed US Service members. However, there is limited information regarding kinesiophobia in Service members with non-operative knee diagnoses. HYPOTHESES: The objectives of this study were to determine the prevalence of high levels of kinesiophobia in US military Service members with knee pain across different knee diagnoses, and to determine the relationships between kinesiophobia and lower extremity function and/or specific functional limitations in Service members with knee pain. It was hypothesized Service members with knee pain would exhibit high levels of kinesiophobia across all knee diagnoses examined, and higher levels of both kinesiophobia and pain would be associated with worse self-reported function in this population. It was also hypothesized higher levels of kinesiophobia would be associated with functional activities with high knee loading. DESIGN: Retrospective cohort study. LEVEL OF EVIDENCE: IV. METHODS: Sixty-five US Service members presenting to an outpatient physical therapy clinic were included in this study (20 females; age = 30.8 ± 7.7 years; height = 1.74 ± 0.9 m; mass = 80.7 ± 16.2 kg). Inclusion criterion was the presence of knee pain (duration = 50 ± 59 months); exclusion criterion was knee pain as a sequela of knee surgery. Data regarding demographic, pain chronicity, pain by Numeric Rating Scale (NRS), Tampa Scale of Kinesiophobia (TSK), and Lower Extremity Functional Scale (LEFS) were retrospectively obtained from patients' medical records. A high level of kinesiophobia was defined as a TSK score of greater than 37 points. Patient diagnoses included: osteoarthritis (n = 16); patellofemoral pain syndrome (n = 23); and other non-operative knee diagnoses (n = 26). Commonality analysis was utilized to determine the effects of age, height, mass, NRS, and TSK on LEFS score. Predictor values were interpreted as <1% = negligible, >1% = small; >9% = moderate, >25% = large. Additionally, exploratory item-specific analyses examined the strength of the relationships between kinesiophobia and LEFS item responses. Binary logistic regression determined if difficulty with an individual LEFS item could be predicted from either NRS or TSK score. Statistical significance was set at P < 0.05. RESULTS: High levels of kinesiophobia were identified in 43 individuals (66%). NRS and TSK explained 19.4% and 8.6% of the unique variance in LEFS, and 38.5% and 20.5% of total variance, respectively. Age, height, and mass explained negligible to small proportions of the unique variance in LEFS. TSK and NRS were independent predictors for 13/20 individual LEFS items, with odds ratios ranging from 1.12 to 3.05 (P < 0.05). CONCLUSION: The majority of US Service members in this study exhibited high levels of kinesiophobia. Kinesiophobia was significantly related to self-reported functional scores and performance on individual functional tasks in Service members with knee pain. CLINICAL RELEVANCE: Treatment strategies addressing both fear of movement and pain reduction in patients with knee pain may help optimize functional outcomes.

The Influence of Tobacco Use, Alcohol Consumption, and Weight Gain on Development of Secondary Musculoskeletal Injury After Lower Limb Amputation.

OBJECTIVES: To evaluate whether tobacco use, alcohol consumption, and weight gain are associated with the diagnosis of overuse musculoskeletal injuries within the first 12 months after lower limb amputation. DESIGN: Retrospective cohort study. SETTING: Military treatment facilities. PARTICIPANTS: Service members (N=681) with a deployment-related lower limb amputation. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Clinical diagnosis codes associated with musculoskeletal overuse injuries of the lower limb, upper limb, and low back regions. RESULTS: In the first three months after amputation, tobacco use and alcohol consumption were reported in 55.7% and 72.0%, respectively, of the retrospective sample. The overall mean weight change was 22.9±23.6 pounds. The prevalence of reporting at least 1 overuse injury within 4 to 12 months after amputation was 57.0% in the sample, with prevalence rates of lower limb, upper limb and low back pain diagnoses at 28.3%, 21.7%, and 21.1%, respectively. Service members reporting tobacco use in the first 3 months after amputation were nearly twice as likely to be diagnosed with a lower limb musculoskeletal injury 4 to 12 months after amputation. Similarly, service members reporting alcohol consumption within the first 3 months after amputation were more than twice as likely to be diagnosed with at least 1 overuse musculoskeletal injury 4 to 12 months after amputation. However, weight change or maximum weight after amputation were not associated with the diagnosis of an overuse musculoskeletal injury. CONCLUSIONS: Development of secondary overuse musculoskeletal injury appears to be related to tobacco use and alcohol consumption, but not to weight gain. These findings warrant focused research efforts toward developing preventive interventions.

A Stimulus-Response Framework to Investigate the Influence of Continuous Versus Interval Walking Exercise on Select Serum Biomarkers in Knee Osteoarthritis.

OBJECTIVE: The aim of the study was to compare changes in the concentration of serum biomarkers in response to continuous versus interval walking exercise in participants with knee osteoarthritis. DESIGN: This study used a two-phase sequential design. Twenty-seven participants with unilateral knee osteoarthritis completed two separate treadmill walking sessions: (1) continuous 45-min walking exercise and (2) three 15-min bouts of walking exercise separated by 1-hr rest periods for a total of 45 mins in an interval format. Participants reported their knee pain using the numeric pain rating scale and serum levels of biomarkers associated with tissue turnover (cartilage oligomeric matrix protein), inflammation (tumor necrosis factor α), and pain (neuropeptide Y) were evaluated at baseline and every 15 mins for both conditions. RESULTS: Continuous walking resulted in a cumulative increase in cartilage oligomeric matrix protein concentration up to 45 mins, whereas interval walking was associated with return of cartilage oligomeric matrix protein concentrations back to baseline at 45 mins. There were no significant changes in tumor necrosis factor α and neuropeptide Y concentration during walking. There was a significant increase in pain compared with baseline in the continuous walking regimen only. CONCLUSIONS: Incorporating rest breaks in walking regimens may affect the potential deleterious effects of longer continuous bouts on the knee joint as well as limit pain during exercise.

Role of peripatellar retinaculum in transmission of forces within the extensor mechanism.

BACKGROUND: The role of the peripatellar retinaculum as a frontal plane stabilizer of the patellofemoral joint has been well established. However, as a result of its unique orientation, the retinaculum also may influence the distribution of forces within the extensor mechanism. The objective of this study was to determine the extent to which the peripatellar retinaculum affects the magnitude of forces experienced by the patellar tendon. METHODS: Ten cadaver knees were used in this investigation. Each was mounted on a custom test apparatus that was fixed to an Instron frame. The extensor mechanism was loaded by applying forces through the individual heads of the quadriceps femoris. Patellar tendon tension was measured at 0 degrees , 20 degrees , 40 degrees , and 60 degrees of knee flexion with use of a buckle transducer under two conditions: (1) with the peripatellar retinaculum intact, and (2) with the peripatellar retinaculum removed. Patellar tendon tension was compared between the two conditions across the knee flexion angles. RESULTS: At each knee flexion angle, the patellar tendon tension was greater with the retinaculum removed than it was with the retinaculum intact. However, the difference was significant only at 0 degrees and 60 degrees , at which positions the force transmitted to the patellar tendon was increased by 16.6% and 9.6%, respectively. CONCLUSIONS: The observed increases in patellar tendon tension after removal of the peripatellar retinaculum is an indication of the load-sharing function of that structure as a part of the extensor mechanism. CLINICAL RELEVANCE: Our results suggest that compromise of the peripatellar retinaculum may alter patellar tendon and/or patellofemoral joint forces.