Susan M. Tillman

Rotational Motion Changes in the Glenohumeral Joint of the Adolescent/Little League Baseball Player

Background Differences in range of motion and rotational motion between the dominant and nondominant shoulders in throwing athletes are well documented, although the age at which these changes begin to occur is not known. Hypothesis Changes in glenohumeral rotational motion in the shoulder of the Little League/adolescent baseball player occur during the most formative years of physical development. Study Design Cross-sectional study. Methods Elevation, internal rotation at 90° of abduction, and external rotation at 90° of abduction were measured in the dominant and nondominant shoulders of 294 baseball players, aged 8 to 16 years. Results Analysis of variance revealed 2-way interactions between arm dominance by age for elevation (P =. 005) and internal rotation (P =. 001). Significant differences were noted between dominant and nondominant arms for internal rotation at 90° (P =.001) and external rotation at 90° (P =. 001). Elevation, internal rotation at 90°, external rotation at 90°, and total range of motion varied significantly (P =. 001) among age groups. Elevation in the dominant arms of 16-year-olds was on average 5.3° less than in 8-year-olds (179.6° vs 174.3°). In the nondominant arms, mean elevation for 16-year-olds was 5.6° less than in 8-year-olds (179.7° vs 174.1°). Internal rotation at 90° for the dominant arms averaged 39.0° at age 8 and only 21.3° at age 16. In the non-dominant arms, internal rotation for 8-year-olds averaged 42.2° and only 33.1° for 16-year-olds. Conclusions Elevation and total range of motion decreased as age increased. These changes may be consequences of both bone and soft tissue adaptation. The most dramatic decline in total range of motion was seen between the 13-year-olds and 14-year-olds, in the year before peak incidence of Little Leaguers shoulder. This decrease in rotational motion may cause increased stress at the physis during throwing.

The Association of Pain and Fear of Movement/Reinjury With Function During Anterior Cruciate Ligament Reconstruction Rehabilitation

STUDY DESIGN Cross-sectional. OBJECTIVES To measure fear of movement/reinjury levels and determine the association with function at different timeframes during anterior cruciate ligament (ACL) reconstruction rehabilitation. We hypothesized that fear of movement/reinjury would decrease during rehabilitation and be inversely related with function. BACKGROUND Fear of movement/reinjury can prevent return to sports after ACL reconstruction, but it has not been studied during rehabilitation. METHODS AND MEASURES Demographic data and responses on the shortened version of Tampa Scale for Kinesiophobia (TSK-11), 8-Item Short-Form Health Survey (SF-8), and International Knee Documentation Committee (IKDC) subjective form were extracted from a clinical database for 97 patients in the first year after ACL reconstruction. Three groups were formed: group 1, less than or equal to 90 days; group 2, 91 to 180 days; group 3: 181 to 372 days post-ACL reconstruction. Group differences in TSK-11 score, SF-8 bodily pain rating, and IKDC scores were determined. Hierarchical linear regression models were created for each group, with IKDC score as the dependent variable and demographic factors, SF-8 bodily pain rating, and TSK-11 score as independent variables. RESULTS TSK-11 score was higher in group 1 than in group 3 (P < .05). Across the groups, SF-8 bodily pain rating decreased (P < .001) and IKDC score increased (P < .001). SF-8 bodily pain rating was a significant factor in the regression model for all groups, whereas TSK-11 score only contributed to the regression model in group 3 (partial correlation, -0.529). CONCLUSIONS Pain was consistently associated with function across the timeframes studied. Fear of movement/reinjury levels appear to decrease during ACL reconstruction rehabilitation and are associated with function in the timeframe when patients return to sports. LEVEL OF EVIDENCE Prognosis, level 4.

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.

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.

Morbid Obesity Is Associated With Fear of Movement and Lower Quality of Life in Patients With Knee Pain-Related Diagnoses

To compare fear of movement in patients with different body mass index (BMI) values referred for rehabilitative care of the knee and to examine whether this fear contributed to self‐reported knee‐related function. We hypothesized that fear of movement would be elevated with increasing BMI and that fear would correspond with lower self‐report knee‐related function and lower quality of life (QOL).

Lower Extremity Stiffness Changes after Concussion in Collegiate Football Players.

Purpose Recent research indicates that a concussion increases the risk of musculoskeletal injury. Neuromuscular changes after concussion might contribute to the increased risk of injury. Many studies have examined gait postconcussion, but few studies have examined more demanding tasks. This study compared changes in stiffness across the lower extremity, a measure of neuromuscular function, during a jump-landing task in athletes with a concussion (CONC) to uninjured athletes (UNINJ). Methods Division I football players (13 CONC and 26 UNINJ) were tested pre- and postseason. A motion capture system recorded subjects jumping on one limb from a 25.4-cm step onto a force plate. Hip, knee, and ankle joint stiffness were calculated from initial contact to peak joint flexion using the regression line slopes of the joint moment versus the joint angle plots. Leg stiffness was (peak vertical ground reaction force [PVGRF]/lower extremity vertical displacement) from initial contact to peak vertical ground reaction force. All stiffness values were normalized to body weight. Values from both limbs were averaged. General linear models compared group (CONC, UNINJ) differences in the changes of pre- and postseason stiffness values. Results Average time from concussion to postseason testing was 49.9 d. The CONC group showed an increase in hip stiffness (P = 0.03), a decrease in knee (P = 0.03) and leg stiffness (P = 0.03), but no change in ankle stiffness (P = 0.65) from pre- to postseason. Conclusion Lower extremity stiffness is altered after concussion, which could contribute to an increased risk of lower extremity injury. These data provide further evidence of altered neuromuscular function after concussion.

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

Observational Ratings of Frontal Plane Knee Position Are Related to the Frontal Plane Projection Angle but Not the Knee Abduction Angle During a Step-down Task

STUDY DESIGN Laboratory study, cross-sectional. OBJECTIVES To determine if the magnitude of frontal plane knee angle, as determined with a 3-D motion-capture system (knee abduction angle [KAA]) or digital video (frontal plane projection angle [FPPA]), varies among groups of individuals with different frontal plane knee position, as determined by observational ratings. BACKGROUND Performing functional tasks with the knee positioned medial to the foot may increase the risk for knee injury. The KAA and FPPA are commonly used in research settings to determine injury risk. However, observational ratings of frontal plane knee position are easier to perform in the clinical setting. It is not clear whether observational ratings of knee position can be used as a surrogate for the KAA or FPPA. METHODS Eighty-one female collegiate athletes performed a lateral step-down task. Participants were rated as good, fair, or poor based on observation of their knee position relative to the foot in the frontal plane and assigned to observational rating groups. Movement was concurrently recorded with a 3-D motion-capture system and a digital video camera to calculate KAA and FPPA, respectively. RESULTS Knee abduction angle did not differ among participants assigned to the different observational rating groups (P = .265). In contrast, FPPA values differed between groups (P<.001), with the highest values in the poor group and the lowest values in the good group. CONCLUSION Observational ratings of frontal plane knee position relative to the foot are an appropriate clinical substitute for FPPA but not KAA. Therefore, observational ratings of medial knee position may be more suitable as a clinical screening tool when FPPA is the measure of interest.

Normalization Considerations for Using the Unilateral Seated Shot Put Test in Rehabilitation

STUDY DESIGN Cross-sectional study. OBJECTIVES To examine the effect of different normalization methods on unilateral seated shot put test results. BACKGROUND The unilateral seated shot put test could assist clinical decision making in upper extremity rehabilitation, but test results must be normalized to compare across patients. The effect of normalization methods based on body size and upper-limb dominance is unknown. METHODS One hundred twenty-five collegiate athletes (63 males) performed the unilateral seated shot put test with each upper extremity. Anthropometric measures (height, body mass, arm length) and distance thrown were recorded. Normalization based on body size included ratio scaling and allometric scaling. Ratio scaling was performed with the anthropometric measure having the highest correlation to distance thrown (distance/anthropometric measure). Allometric scaling was performed with body mass raised to the theoretical exponent 0.67 (distance/body mass(0.67)) and a derived exponent. Correlations of nonnormalized and normalized values with body mass were then determined. The limb symmetry index [(dominant-side distance/nondominantside distance) × 100] was used for normalization based on limb dominance. Sex differences were examined. RESULTS Body mass was selected for ratio scaling, and 0.35 was the derived allometric-scaling exponent. Across sexes, only allometric scaling with the exponent 0.35 removed the correlation with body mass. The mean limb symmetry index exceeded 100% in males (108.7%) and females (104.4%). All normalized test results were higher in males. CONCLUSION When using the unilateral seated shot put test in rehabilitation, allometric scaling with the exponent 0.35 is preferable, limb comparisons should account for 5% to 10% better performance on the dominant side, and performance benchmarks should be set within sex. J Orthop Sports Phys Ther 2014;44(7):518-524. Epub 10 May 2014. doi:10.2519/jospt.2014.5004.