STUDY DESIGN: Controlled laboratory study. OBJECTIVES: To assess scapular kinematics and electromyographic signal amplitude of the shoulder musculature, before and after thoracic spine manipulation (TSM) in subjects with rotator cuff tendinopathy (RCT). Changes in range of motion, pain, and function were also assessed. BACKGROUND: There are various treatment techniques for RCT. Recent studies suggest that TSM may be a useful component in the management of pain and dysfunction associated with RCT. METHODS: Thirty subjects between 18 and 45 years of age, who showed signs of RCT, participated in this study. Changes in scapular kinematics and muscle activity, as well as changes in shoulder pain and function, were assessed pre-TSM and post-TSM using paired t tests and repeated-measures analyses of variance. RESULTS: TSM did not lead to changes in range of motion or scapular kinematics, with the exception of a small decrease in scapular upward rotation (P = .05). The only change in muscle activity was a small but significant increase in middle trapezius activity (P = .03). After TSM, subjects demonstrated decreased pain during performance of the Jobe empty-can (mean ± SD change, 2.6 ± 1.1), Neer (2.6 ± 1.3), and Hawkins-Kennedy (2.8 ± 1.3) tests (all, P<.001). Subjects also reported decreased pain with shoulder flexion (mean ± SD change, 2.0 ± 1.5; P<.001) and improved shoulder function (force production, 2.5 ± 1.4 kg; Penn Shoulder Score, 7.7 ± 9.4; sports/performing arts module of the Disabilities of the Arm, Shoulder and Hand questionnaire, 16.4 ± 13.2) (all, P<.001). CONCLUSION: Immediate improvements in shoulder pain and function post-TSM are not likely explained by alterations in scapular kinematics or shoulder muscle activity. For people with pain associated with RCT, TSM may be an effective component of their treatment plan to improve pain and function. However, further randomized controlled studies are necessary to better validate this treatment approach. LEVEL OF EVIDENCE: Therapy, level 4.

J Orthop Sports Phys Ther 2012;42(12):1005-1016, Epub 17 August 2012. doi:10.2519/jospt.2012.4142

KEY WORDS: joint mobilization, manual therapy, scapula, shoulder impingement

STUDY DESIGN: Within-subject, repeated-measures design. OBJECTIVES: To measure tibiofemoral contact forces during cycling in vivo and to quantify the influences of power, pedaling cadence, and seat height on tibiofemoral contact forces. BACKGROUND: Cycling is usually classified as a low-demand activity for the knee joint and is therefore recommended for persons with osteoarthritis and rehabilitation programs following knee surgery. However, there are limited data regarding actual joint loading. METHODS: Instrumented knee implants with telemetric data transmission were used to measure the tibiofemoral contact forces. Data were obtained in 9 subjects, during ergometer cycling and walking, 15 ± 7 months after total knee arthroplasty. Tibiofemoral forces during cycling at power levels between 25 and 120 W, cadences of 40 and 60 rpm, and 2 seat heights were investigated. RESULTS: Within the examined power range, tibiofemoral forces during cycling were smaller than those during walking. At the moderate condition of 60 W and 40 rpm, peak resultant forces of 119% of body weight were measured during the pedal downstroke. Shear forces ranged from 5% to 7% of body weight. Forces increased linearly with cycling power. Higher cadences led to smaller forces. A lower seat height did not increase the resultant force but caused higher posterior shear forces. CONCLUSION: Due to the relatively small tibiofemoral forces, cycling with moderate power levels is suited for individuals with osteoarthritis and rehabilitation programs following knee surgery, such as cartilage repair or total knee replacement. The lowest forces can be expected while cycling at a low power level, a high cadence, and a high seat height.

J Orthop Sports Phys Ther 2012;42(12):1032-1038, Epub 5 September 2012. doi:10.2519/jospt.2012.4001

KEY WORDS: force, telemetry, tibiofemoral, TKR

Editor-in-Chief Dr. Guy Simoneau recognizes the authors, associate editors, International Editorial Review Board members, and manuscript and musculoskeletal imaging reviewers who contributed to the various aspects of the Journal over the past 12 months.

J Orthop Sports Phys Ther 2012;42(12):982-984. doi:10.2519/jospt.2012.0112

KEY WORDS: authors, editorial board, reviewers

STUDY DESIGN: Cross-sectional. OBJECTIVE: To investigate predictors of increased frontal plane knee projection angle (FPKPA) in athletes. BACKGROUND: The underlying mechanisms that lead to increased FPKPA are likely multifactorial and depend on how the musculoskeletal system adapts to the possible interactions between its distal and proximal segments. Bivariate and linear analyses traditionally employed to analyze the occurrence of increased FPKPA are not sufficiently robust to capture complex relationships among predictors. The investigation of nonlinear interactions among biomechanical factors is necessary to further our understanding of the interdependence of lower-limb segments and resultant dynamic knee alignment. METHODS: The FPKPA was assessed in 101 athletes during a single-leg squat and in 72 athletes at the moment of landing from a jump. The investigated predictors were sex, hip abductor isometric torque, passive range of motion (ROM) of hip internal rotation (IR), and shank-forefoot alignment. Classification and regression trees were used to investigate nonlinear interactions among predictors and their influence on the occurrence of increased FPKPA. RESULTS: During single-leg squatting, the occurrence of high FPKPA was predicted by the interaction between hip abductor isometric torque and passive hip IR ROM. At the moment of landing, the shank-forefoot alignment, abductor isometric torque, and passive hip IR ROM were predictors of high FPKPA. In addition, the classification and regression trees established cutoff points that could be used in clinical practice to identify athletes who are at potential risk for excessive FPKPA. CONCLUSION: The models captured nonlinear interactions between hip abductor isometric torque, passive hip IR ROM, and shank-forefoot alignment.

J Orthop Sports Phys Ther 2012;42(12):996-1004, Epub 18 September 2012. doi:10.2519/jospt.2012.4041

KEY WORDS: anterior cruciate ligament, CART, dynamic knee alignment, hip strength, patellofemoral joint

STUDY DESIGN: Longitudinal cross-sectional study. BACKGROUND: In the early stages after total knee arthroplasty (TKA), quadriceps strength of the operated limb decreases and is substantially less than that of the nonoperated limb. This asymmetry in strength is related to asymmetrical movement patterns that increase reliance on the nonoperated limb. Over time, quadriceps strength in the operated limb increases but remains less than that in age-matched controls without knee pathology, whereas the quadriceps strength in the nonoperated limb gradually decreases. The purpose of this study was to investigate the changes in quadriceps strength and function of both limbs up to 3 years after TKA and to evaluate change in interlimb kinematic and kinetic parameters over time compared to that in age-matched individuals without knee pathology. METHODS: Fourteen individuals after TKA and 14 healthy individuals matched for age, weight, height, and sex participated in the study. Outcome measures included kinematics, kinetics, quadriceps strength, and functional performance. RESULTS: In participants who underwent TKA, quadriceps strength was significantly different between limbs at 3 months and 1 year after TKA, but not at 3 years after TKA. In this group, there was also a significant improvement in self-reported function between 3 months and 1 year after TKA, but a significant decrease between years 1 and 3 for the physical component summary score of the Medical Outcomes Study 36-Item Short-Form Health Survey. In the TKA group, there were few interlimb differences in joint kinematics and kinetics 3 years after TKA, which may be attributed to a combination of worsening in the nonoperated limb, as well as improvement in the operated limb. Differences between participants without knee pathology and those 3 years after TKA still existed for kinematic, kinetic, and spatiotemporal variables. CONCLUSION: As interlimb differences in quadriceps strength decrease after TKA, there are concomitant symmetrical improvements in temporospatial and kinetic gait parameters. The symmetry 3 years after TKA in quadriceps strength is primarily the result of progressive weakness in the nonoperated limb.

J Orthop Sports Phys Ther 2012;42(12):1039-1049, Epub 22 October 2012. doi:10.2519/jospt.2012.3763

KEY WORDS: biomechanics, joint replacement, walking

The patient was a 61-year-old woman who was referred to a physical therapist with a diagnosis of right common fibular neuropathy at the fibular head involving both the deep and superficial nerve branches. Physical therapist intervention included fitting the patient with a right ankle-foot orthosis and referring the patient to her physician due to concern for a potential compressive lesion at the right proximal tibiofibular joint. Subsequent magnetic resonance imaging identified a lobulated, fluid-filled mass likely representing a ganglion cyst.

J Orthop Sports Phys Ther 2012;42(12):1051. doi:10.2519/jospt.2012.0421

KEY WORDS: ankle, lower leg, magnetic resonance imaging, tibiofibular joint