Michael W. Moser

Evidence for a biopsychosocial influence on shoulder pain: Pain catastrophizing and catechol-O-methyltransferase (COMT) diplotype predict clinical pain ratings

&NA; The experience of pain is believed to be influenced by social, cultural, environmental, psychological, and genetic factors. Despite this assertion, few studies have included clinically relevant pain phenotypes when investigating interactions among these variables. This study investigated whether psychological variables specific to fear‐avoidance models and catechol‐O‐methyltransferase (COMT) genotype influenced pain ratings for a cohort of patients receiving operative treatment of shoulder pain. Patients (n = 58) completed questionnaires and had COMT genotype determined pre‐operatively. Then, shoulder pain ratings were collected 3–5 months post‐operatively. This cohort consisted of 24 females and 34 males, with mean age of 50.3 (SD = 15.0) and pre‐operative pain rating of 4.5/10 (SD = 1.8). The frequency of COMT diplotypes was 34 with “high COMT activity” (LPS group) and 24 with “low COMT activity” (APS/HPS group). Preliminary analysis indicated that of all the fear‐avoidance variables considered (fear of pain, kinesiophobia, pain catastrophizing, and anxiety), only pain catastrophizing was a unique contributor to clinical pain ratings. A hierarchical regression model indicated that an interaction between pain catastrophizing and COMT diplotype contributed additional variance in pre‐operative pain ratings. The pain catastrophizing × COMT diplotype interaction demonstrated predictive validity as patients with high pain catastrophizing and low COMT activity (APS/HPS group) were more likely (RR = 6.8, 95% CI = 2.8–16.7) to have post‐operative pain ratings of 4.0/10 or higher. Our findings suggest that an interaction between pain catastrophizing and COMT diplotype has the potential to influence pain ratings in patients seeking operative treatment of their shoulder pain.

Longitudinal Changes in Psychosocial Factors and Their Association With Knee Pain and Function After Anterior Cruciate Ligament Reconstruction

Background Evidence in the musculoskeletal rehabilitation literature suggests that psychosocial factors can influence pain levels and functional outcome. Objective The purpose of this study was to examine changes in select psychosocial factors and their association with knee pain and function over 12 weeks after anterior cruciate ligament (ACL) reconstruction. Design This was a prospective, longitudinal, observational study. Methods Patients with ACL reconstruction completed self-report questionnaires for average knee pain intensity (numeric rating scale [NRS]), knee function (International Knee Documentation Committee Subjective Knee Form [IKDC-SKF]), and psychosocial factors (pain catastrophizing [Pain Catastrophizing Scale], fear of movement or reinjury [shortened version of the Tampa Scale for Kinesiophobia (TSK-11)], and self-efficacy for rehabilitation tasks [modified Self-Efficacy for Rehabilitation Outcome Scale (SER)]). Data were collected at 4 time points after surgery (baseline and 4, 8, and 12 weeks). Repeated-measures analyses of variance determined changes in questionnaire scores across time. Hierarchical linear regression models were used to examine the association of psychosocial factors with knee pain and function. Results Seventy-seven participants completed the study. All questionnaire scores changed across 12 weeks. Baseline psychosocial factors did not predict the 12-week NRS or IKDC-SKF score. The 12-week change in modified SER score predicted the 12-week change in NRS score (r2=.061), and the 12-week change in modified SER and TSK-11 scores predicted the 12-week change in IKDC-SKF score (r2=.120). Limitations The psychometric properties of the psychosocial factor questionnaires are unknown in people with ACL reconstruction. The study focused on short-term outcomes using only self-report measures. Conclusions Psychosocial factors are potentially modifiable early after ACL reconstruction. Baseline psychosocial factor levels did not predict knee pain or function 12 weeks postoperatively. Interventions that increase self-efficacy for rehabilitation tasks or decrease fear of movement or reinjury may have potential to improve short-term outcomes for knee pain and function.

Comparison of Physical Impairment, Functional, and Psychosocial Measures Based on Fear of Reinjury/Lack of Confidence and Return-to-Sport Status After ACL Reconstruction

Background: Fear of reinjury and lack of confidence influence return-to-sport outcomes after anterior cruciate ligament (ACL) reconstruction. The physical, psychosocial, and functional recovery of patients reporting fear of reinjury or lack of confidence as their primary barrier to resuming sports participation is unknown. Purpose: To compare physical impairment, functional, and psychosocial measures between subgroups based on return-to-sport status and fear of reinjury/lack of confidence in the return-to-sport stage and to determine the association of physical impairment and psychosocial measures with function for each subgroup at 6 months and 1 year after surgery. Study Design: Case-control study; Level of evidence, 3. Methods: Physical impairment (quadriceps index [QI], quadriceps strength/body weight [QSBW], hamstring:quadriceps strength ratio [HQ ratio], pain intensity), self-report of function (International Knee Documentation Committee [IKDC]), and psychosocial (Tampa Scale for Kinesiophobia–shortened form [TSK-11]) measures were collected at 6 months and 1 year after surgery in 73 patients with ACL reconstruction. At 1 year, subjects were divided into “return-to-sport” (YRTS) or “not return-to-sport” (NRTS) subgroups based on their self-reported return to preinjury sport status. Patients in the NRTS subgroup were subcategorized as NRTS-Fear/Confidence if fear of reinjury/lack of confidence was the primary reason for not returning to sports, and all others were categorized as NRTS-Other. Results: A total of 46 subjects were assigned to YRTS, 13 to NRTS-Other, and 14 to NRTS-Fear/Confidence. Compared with the YRTS subgroup, the NRTS-Fear/Confidence subgroup was older and had lower QSBW, lower IKDC score, and higher TSK-11 score at 6 months and 1 year; however, they had similar pain levels. In the NRTS-Fear/Confidence subgroup, the IKDC score was associated with QSBW and pain at 6 months and QSBW, QI, pain, and TSK-11 scores at 1 year. Conclusion: Elevated pain-related fear of movement/reinjury, quadriceps weakness, and reduced IKDC score distinguish patients who are unable to return to preinjury sports participation because of fear of reinjury/lack of confidence. Despite low average pain ratings, fear of pain may influence function in this subgroup. Assessment of fear of reinjury, quadriceps strength, and self-reported function at 6 months may help identify patients at risk for not returning to sports at 1 year and should be considered for inclusion in return-to-sport guidelines.

Functional outcome of surgically treated massive rotator cuff tears: a comparison of complete repair, partial repair, and debridement.

Functional outcomes of three surgical treatments for massive rotator cuff repairs were compared. Surgery was performed by a single surgeon (T.W.W.) on 38 patients (mean age: 62.5 years). The surgeon decided which procedure to use for each patient based on tissue quality, ability to mobilize the torn rotator cuff, and degree of tension after the repair was attempted. Twenty-one patients underwent complete repair, 11 underwent partial repair, and 6 had debridement alone. Results were evaluated using the Shoulder Pain and Disability Index and by measuring range of motion and strength. The mean Shoulder Pain and Disability Index score for all patients postoperatively was 25, with subindices averaging 10 for pain and 15 for function. For the subgroups, Shoulder Pain and Disability Index scores for pain and function, were 8 and 10 for complete repair, 11 and 19 for partial repair, and 14 and 24 for debridement alone, respectively. Active external rotation was significantly better (P = .008) postoperatively in patients who had a complete repair compared to debridement alone.

Factors Associated With Function After Anterior Cruciate Ligament Reconstruction

Background: Many individuals do not resume unrestricted, preinjury sports participation after anterior cruciate ligament reconstruction, thus a better understanding of factors associated with function is needed. The purpose of this study was to investigate the association of knee impairment and psychological variables with function in subjects with anterior cruciate ligament reconstruction. Hypothesis: After controlling for demographic variables, knee impairment and psychological variables contribute to function in subjects with anterior cruciate ligament reconstruction. Study Design: Cross-sectional study; Level of evidence, 4a. Methods: Fifty-eight subjects with a unilateral anterior cruciate ligament reconstruction completed a standardized testing battery for knee impairments (range of motion, effusion, quadriceps strength, anterior knee joint laxity, and pain intensity), kinesiophobia (shortened Tampa Scale for Kinesiophobia), and function (International Knee Documentation Committee subjective form and single-legged hop test). Separate 2-step regression analyses were conducted with International Knee Documentation Committee subjective form score and single-legged hop index as dependent variables. Demographic variables were entered into the model first, followed by knee impairment measures and Tampa Scale for Kinesiophobia score. Results: A combination of pain intensity, quadriceps index, Tampa Scale for Kinesiophobia score, and flexion motion deficit contributed to the International Knee Documentation Committee subjective form score (adjusted r 2 = 0.67; P < .001). Only effusion contributed to the single-legged hop index (adjusted r 2 = 0.346; P = .002). Conclusion: Knee impairment and psychological variables in this study were associated with self-report of function, not a performance test. Clinical Relevance: The results support focusing anterior cruciate ligament reconstruction rehabilitation on pain, knee motion deficits, and quadriceps strength, as well as indicate that kinesiophobia should be addressed. Further research is needed to reveal which clinical tests are associated with performance testing.

Investigation of central pain processing in postoperative shoulder pain and disability.

Background:Measures of central pain processing like conditioned pain modulation and suprathreshold heat pain response (SHPR) have been described to assess different components of central pain modulatory mechanisms. Central pain processing potentially plays a role in the development of postsurgical pain, however, the role of conditioned pain modulation and SHPR in explaining postoperative clinical pain and disability is still unclear. Methods:Seventy-eight patients with clinical shoulder pain were included in this study. Patients were examined before shoulder surgery, at 3 months, and 6 months after surgery. The primary outcome measures were pain intensity and upper extremity disability. Results:Analyses revealed that the change score (baseline- 3 mo) of fifth pain rating of SHPR accounted for a significant amount of variance in 6-month postsurgical clinical pain intensity and disability after age, sex, preoperative pain intensity, and relevant psychological factors were considered. Conclusions:The present study suggests that baseline measures of central pain processing were not predictive of 6-month postoperative pain outcome. Instead, the 3-month change in SHPR might be a relevant factor in the transition to an elevated 6-month postoperative pain and disability outcomes. In patients with shoulder pain, the 3-month change in a measure of central pain processing might be a relevant factor in the transition to elevated 6-month postoperative pain and disability scores.

Urinary CTX-II concentrations are elevated and associated with knee pain and function in subjects with ACL reconstruction

OBJECTIVE Post-traumatic knee osteoarthritis (OA) is prevalent after anterior cruciate ligament reconstruction (ACLR). Biomarkers that identify individuals likely to develop OA, especially symptomatic OA, can help target preventative and therapeutic strategies. This study examined the magnitude and change over time in urinary CTX-II (uCTX-II) concentrations shortly after ACL reconstruction, and, secondarily, the associations with knee pain and function. DESIGN Subjects were 28 patients with ACLR and 28 age- and sex-matched controls (CNTRL). Testing was conducted at four time points spaced 4 weeks apart (4, 8, 12 and 16 weeks post-operative in ACLR). Measures included demographics, urine samples, Numeric Pain Rating Scale (NPRS) and International Knee Documentation Committee Subjective Knee Form (IKDC-SKF). uCTX-II concentrations were determined with competitive enzyme-linked immunosorbent assay (ELISA). uCTX-II concentrations at each time point in ACLR were compared to the mean concentration over time in CNTRL, with and without adjustment for body mass index (BMI). Changes over time in each measure and correlations between the slopes of change were examined. RESULTS uCTX-II concentrations were significantly higher in ACLR than CNTRL through 16 weeks post-operative when adjusted for BMI. In ACLR, uCTX-II concentrations significantly decreased over time, and the slope was associated with NPRS (r = 0.406, P = 0.039) and IKDC-SKF (r = -0.402, P = 0.034) slopes. CONCLUSION uCTX-II concentrations shortly after ACLR were elevated compared to CNTRL and declined over time. Decreasing uCTX-II concentrations were associated with decreasing knee pain and improving function. uCTX-II may have a role as a prognostic marker following ACLR and warrants further investigation.

Preliminary results of patient-defined success criteria for individuals with musculoskeletal pain in outpatient physical therapy settings

OBJECTIVES (1) To investigate patient-defined parameters of treatment success in an outpatient physical therapy setting with musculoskeletal pain, (2) to determine whether patient-defined treatment success was influenced by selected demographic and clinical factors, and (3) to examine whether patient subgroups existed for ratings of importance for each treatment outcome domain. DESIGN Cross-sectional study. SETTING Outpatient physical therapy clinic. PARTICIPANTS Consecutive patients (N=110) with complaints of musculoskeletal pain. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURE We reported patient-defined treatment success targets for pain, fatigue, emotional distress, and interference with daily activities using the Patient-Centered Outcomes Questionnaire (PCOQ). We also investigated whether patient subgroups existed based on perceived importance of improvement for these same outcome domains. RESULTS Patient-defined criteria for treatment success included mean reductions (from baseline scores) in pain of 3.0 points, in fatigue of 2.3 points, in emotional distress of 1.4 points, and in interference with daily activities of 3.4 points. There were no differences in patient-defined criteria for treatment success based on sex, age, postoperative rehabilitation, prior physical therapy, other prior health care interventions, duration of symptoms, and anatomical location of symptoms (P>.01). Cluster analysis of the PCOQ importance ratings indicated a 2-cluster solution. The multifocused subgroup demonstrated higher importance for improvement ratings in each treatment outcome domain when compared with the pain-focused subgroup (P>.05). CONCLUSIONS These data indicate that patient-defined criteria for treatment success required greater reductions in the studied outcome domains to be considered successful. These data suggest the potential existence of patient subgroups that either rate improvement in all outcome domains as important or rate pain relief as the most important outcome.

Biopsychosocial influence on shoulder pain: risk subgroups translated across preclinical and clinical prospective cohorts.

Abstract Tailored treatment based on individual risk factors is an area with promise to improve options for pain relief. Musculoskeletal pain has a biopsychosocial nature, and multiple factors should be considered when determining risk for chronic pain. This study investigated whether subgroups comprised genetic and psychological factors predicted outcomes in preclinical and clinical models of shoulder pain. Classification and regression tree analysis was performed for an exercise-induced shoulder injury cohort (n = 190) to identify high-risk subgroups, and a surgical pain cohort (n = 150) was used for risk validation. Questionnaires for fear of pain and pain catastrophizing were administered before injury and preoperatively. DNA collected from saliva was genotyped for a priori selected genes involved with pain modulation (COMT and AVPR1A) and inflammation (IL1B and TNF/LTA). Recovery was operationalized as a brief pain inventory rating of 0/10 for current pain intensity and <2/10 for worst pain intensity. Follow-up for the preclinical cohort was in daily increments, whereas follow-up for the clinical cohort was at 3, 6, and 12 months postoperatively. Risk subgroups comprised the COMT high pain sensitivity variant and either pain catastrophizing or fear of pain were predictive of heightened shoulder pain responses in the preclinical model. Further analysis in the clinical model identified the COMT high pain sensitivity variant and pain catastrophizing subgroup as the better predictor. Future studies will determine whether these findings can be replicated in other anatomical regions and whether personalized medicine strategies can be developed for this risk subgroup.

Low- Versus High-Intensity Plyometric Exercise During Rehabilitation After Anterior Cruciate Ligament Reconstruction

Background: Plyometric exercise is used during rehabilitation after anterior cruciate ligament (ACL) reconstruction to facilitate the return to sports participation. However, clinical outcomes have not been examined, and high loads on the lower extremity could be detrimental to knee articular cartilage. Purpose: To compare the immediate effect of low- and high-intensity plyometric exercise during rehabilitation after ACL reconstruction on knee function, articular cartilage metabolism, and other clinically relevant measures. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: Twenty-four patients who underwent unilateral ACL reconstruction (mean, 14.3 weeks after surgery; range, 12.1-17.7 weeks) were assigned to 8 weeks (16 visits) of low- or high-intensity plyometric exercise consisting of running, jumping, and agility activities. Groups were distinguished by the expected magnitude of vertical ground-reaction forces. Testing was conducted before and after the intervention. Primary outcomes were self-reported knee function (International Knee Documentation Committee [IKDC] subjective knee form) and a biomarker of articular cartilage degradation (urine concentrations of crosslinked C-telopeptide fragments of type II collagen [uCTX-II]). Secondary outcomes included additional biomarkers of articular cartilage metabolism (urinary concentrations of the neoepitope of type II collagen cleavage at the C-terminal three-quarter–length fragment [uC2C], serum concentrations of the C-terminal propeptide of newly formed type II collagen [sCPII]) and inflammation (tumor necrosis factor–α), functional performance (maximal vertical jump and single-legged hop), knee impairments (anterior knee laxity, average knee pain intensity, normalized quadriceps strength, quadriceps symmetry index), and psychosocial status (kinesiophobia, knee activity self-efficacy, pain catastrophizing). The change in each measure was compared between groups. Values before and after the intervention were compared with the groups combined. Results: The groups did not significantly differ in the change of any primary or secondary outcome measure. Of interest, sCPII concentrations tended to change in opposite directions (mean ± SD: low-intensity group, 28.7 ± 185.5 ng/mL; high-intensity group, −200.6 ± 255.0 ng/mL; P = .097; Cohen d = 1.03). Across groups, significant changes after the intervention were increased the IKDC score, vertical jump height, normalized quadriceps strength, quadriceps symmetry index, and knee activity self-efficacy and decreased average knee pain intensity. Conclusion: No significant differences were detected between the low- and high-intensity plyometric exercise groups. Across both groups, plyometric exercise induced positive changes in knee function, knee impairments, and psychosocial status that would support the return to sports participation after ACL reconstruction. The effect of plyometric exercise intensity on articular cartilage requires further evaluation. Registration Number: Clinicaltrials.gov NCT01851655