For some patients, spinal manipulative therapy is an effective treatment for spine pain, yet we really don't fully understand how or why. The mechanisms of spinal manipulative therapy are not well defined, and common explanations for why spinal manipulative therapy works lack supporting evidence. Traditionally, the decision to incorporate spinal manipulative therapy into a plan of care is based on a seductively plausible biomechanical theory. Examination techniques, sometimes quite elaborate in nature, are used to determine painful structures and associated abnormalities related to alignment and mobility. The appropriately matched spinal manipulative therapy treatment techniques are then implemented to correct "pathological" findings. The underlying implication of these approacheds is that success of spinal manipulative therapy is dependent upon correction of biomechanical faults detected on examination.

J Orthop Sports Phys Ther. 2008;38(6):293-295. doi:10.2519/jospt.2008.0118

KEY WORDS: biomechanics, spine

STUDY DESIGN: Prospective cohort/predictive validity study. OBJECTIVE: To determine the predictive validity of selected clinical exam items and to develop a clinical prediction rule (CPR) to determine which patients with patellofemoral pain syndrome (PFPS) have a positive immediate response to lumbopelvic manipulation. BACKGROUND: Quadriceps muscle function in patients with PFPS was recently shown to improve following treatment with lumbopelvic manipulation. No previous study has determined if individuals with PFPS experience symptomatic relief of activity-related pain immediately following this manipulation technique. METHODS AND MEASURES:  Fifty subjects (26 male, 24 female; age range, 18-45 years) with PFPS underwent a standardized history and physical examination. After the evaluation, each subject performed 3 typically pain-producing functional activities (squatting, stepping up a 20-cm step, and stepping down a 20-cm step). The pain level perceived during each activity was rated on a numerical pain scale (0 representing no pain and 10 the worst possible pain). Following the assessment, all subjects were treated with a lumbopelvic manipulation, which was immediately followed by retesting the 3 functional activities to determine if there was any change in pain ratings. An immediate overall 50% or greater reduction in pain, or moderate or greater improvement on a global rating of change questionnaire, was considered a treatment success. Likelihood ratios (LRs) were calculated to determine which examination items were most predictive of treatment outcome. RESULTS: Data for 49 subjects were included in the data analysis, of which 22 (45%) had a successful outcome. Five predictor variables were identified. The most powerful predictor of treatment success was a side-to-side difference in hip internal rotation range of motion greater than 14^º (+LR, 4.9). If this variable was present, the chance of experiencing a successful outcome improved from 45% to 80%. CONCLUSION: A CPR was developed to predict an immediate successful response to lumbopelvic manipulation in patients with PFPS. However, in light of a limited sample size and omission of potentially meaningful predictor variables, future studies are necessary to validate the CPR. LEVEL OF EVIDENCE: Prognosis, level 2b.

This article features an invited commentary by Christopher M. Powers, PT, PhD, as well as an authors' response.

J Orthop Sports Phys Ther. 2008;38(6):297-312, published online 22 January 2008. doi:10.2519/jospt.2008.2669

KEY WORDS: anterior knee pain, physical examination, rehabilitation, spinal manipulation

SYNOPSIS: Degeneration of the lumbar intervertebral discs (IVDs) is highly prevalent in adults and is nearly universal in the elderly population. Degenerative changes within, and adjacent to, the IVDs are likely to contribute to a variety of pain syndromes; however, the exact association between these findings and symptoms remains speculative. Recent research has provided new information regarding the etiology, pathophysiology, and clinical relevance of degeneration of the IVD. This information will assist clinicians and researchers in understanding the development and clinical course of lumbar disc degeneration, as well as its potential impact upon patients seeking physical therapy care for back pain. The purposes of this clinical commentary are to review the structure and metabolic capacity of the normal and degenerative lumbar IVD, and to discuss factors that influence the onset and progression of disc degeneration. Lumbar magnetic resonance images will be used to illustrate the common findings associated with this condition. LEVEL OF EVIDENCE: Diagnosis, level 5.

J Orthop Sports Phys Ther. 2008;38(6):329-340, published online 12 March 2008. doi:10.2519/jospt.2008.2768

KEY WORDS: back pain, lumbar disc, MRI, rehabilitation

STUDY DESIGN: Preinstruction and postinstruction testing in a laboratory setting. OBJECTIVES: To examine the predictive relationship between lower extremity muscle strength and the immediate postinstruction changes in landing patterns of female athletes. We hypothesized that greater strength would be associated with larger postinstruction improvements in landing patterns. BACKGROUND: Female athletes in high-demand sports may be predisposed to anterior cruciate ligament injury because of poor landing patterns. Instruction has been shown to improve landing patterns. Lower extremity muscular strength may determine the potential for instruction to alter landing patterns. METHODS AND MEASURES: Thirty-seven female collegiate athletes in high-demand sports participated. Strength was assessed in the following muscle groups: trunk extensors and flexors, hip abductors and extensors, knee flexors and extensors, and ankle plantar flexors. Strength testing was followed by kinetic and kinematic analysis of a drop vertical jump task. Athletes then received verbal instruction on how to improve their landing technique and were retested. Landing variables of interest were force absorption time, peak vertical ground reaction force (vGRF), peak knee flexion and abduction angle, and peak external knee abduction moment. Preinstruction and postinstruction landing variables data were compared. Linear regression models were created with strength values as independent variables and landing variables as dependent variables. RESULTS: After instruction, athletes significantly increased their force absorption time and peak knee flexion angle, while decreasing their peak vGRF, peak knee abduction angle, and peak external knee abduction moment (P<.001). None of the regression models were statistically significant (P>.05). CONCLUSIONS: A brief instructional session promotes short-term improvements in the landing patterns of collegiate female athletes, but muscular strength was a poor predictor of the improvements. LEVEL OF EVIDENCE: Prognosis, level 4.

J Orthop Sports Phys Ther. 2008;38(6):353-361, published online 10 April 2008. doi:10.2519/jospt.2008.2726

KEY WORDS: ACL, biomechanics, hip, knee, motion analysis

STUDY DESIGN: A prospective methodological study of interrater reliability. OBJECTIVES: To examine the interrater reliability of a movement impairment-based classification system for patients with chronic low back pain (LBP). BACKGROUND: Movement impairment-based classification for the lumbar spine categorizes LBP based on the findings derived from a patient history and standardized examination. Though many presume this classification to be useful for directing treatment of individuals with LBP, agreement between examiners for assigning a lumbar spine category to a patient has not been studied thoroughly. METHODS AND MEASURES: Two physical therapists independently examined 24 patients (8 men, 16 women) with chronic LBP (pain duration greater than 12 weeks). All patients enrolled in the study had been diagnosed with LBP that was believed to be due to mechanical causes, and the duration of their symptoms ranged from 20 to 1040 weeks. The examiners used a standardized examination to assess patients and classify them into 1 of 5 lumbar spine categories. Percent agreement and kappa coefficients were calculated between the examiners for the lumbar movement impairment-based classifications. RESULTS: Percent agreement between examiners was 75% and the kappa coefficient was 0.61. The most prevalent lumbar spine categories identified by both examiners were lumbar extension rotation syndrome (41.7% of patients by examiner 1, 37.5% of patients by examiner 2) and lumbar rotation syndrome (41.7% of patients by both examiners). CONCLUSIONS: Interrater reliability between 2 physical therapists classifying patients with chronic LBP patients into 1 of 5 lumbar spine movement impairment categories had substantial agreement.

J Orthop Sports Phys Ther. 2008;38(6):371-376, published online 22 January 2008. doi:10.2519/jospt.2008.2760

KEY WORDS: agreement, diagnostic categories, kappa statistic