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Patellofemoral Pain Syndrome (PFPS) is a common musculoskeletal complaint. The presence of a delay between vastus medialis obliquus (VMO) and vastus lateralis (VL) muscle onset has been suggested in the literature as a possible cause of PFPS, with poor agreement amongst authors on the value of the delay. In this study we computed the delay in the activation of VMO and VL in 15 PFPS patients and 20 age-matched controls (Ctrls) during the following tasks: sit to stand, stand to sit, squat, step up and step down. Activation instants were detected from surface EMG data by a double-threshold statistical detector. In order to compare the muscle activity throughout the task, we computed the delay between the instants in which the VMO and VL normalised envelopes reached subsequent normalised amplitude levels, until the envelope peak. In all investigated tasks but sit to stand, the onset delay was lower or equal then 0.02s, without group differences. Similarly, no differences between Ctrls and PFPS timing were found throughout all tasks, until the peak. Our results do not support the hypothesis that an onset delay between VMO and VL can be one of the causes of PFPS., (Copyright © 2010. Published by Elsevier B.V.)

This prospective study determined whether selected anatomic measures identified women at increased risk of patellofemoral pain syndrome (PFPS) and shin splints (SS). Ten anatomic measures were performed on 748 women before basic training at the Marine Corps Recruit Depot (MCRD), Parris Island, South Carolina. Recruits were then followed throughout basic training for occurrence of injuries. Logistic regression modeling indicated that a left hip internal rotation range of motion (ROM) < or =25 degrees and > or =46 degrees, a right Q angle > or =20 degrees, and left knee hyperextension ROM > or =6 degrees were positively associated with PFPS. Whereas left dorsiflexion ROM > or =21 degrees was associated with SS, right Q angle > or =20 degrees was inversely associated with SS. These findings suggest that multiple anatomic measures can be used to identify women entering MCRD basic training at risk for PFPS and SS injuries.

Objectives: To analyze the electrical activity of the vastus medialis obliquus (VMO), vastus lateralis longus (VLL) and vastus lateralis obliquus (VLO) muscles of individuals with patellofemoral pain syndrome (PFPS) during maximum voluntary isometric contraction (MVIC) of lower leg extension with the knee at 30 degrees; to assess pain using a visual analogue scale (VAS); and to assess patellar positioning using magnetic resonance imaging (MRI)., Methods: Twelve women with PFPS and 12 clinically normal women were evaluated. They performed five MVICs of lower leg extension at 30 degrees for electromyographic (EMG) analysis. Using MRI, the sulcus angle (SA), congruence angle (CA), patellar tilt angle (PTA) and patellar displacement (PD) were obtained. The following statistical tests were used: analysis of variance (ANOVA) for repeated measurements to assess EMGs; Mann-Whitney U test to analyze MRIs; Pearson's (r) correlation test between EMGs and MRIs; and one-way ANOVA to evaluate pain (p < or = 0.05)., Results: In the PFPS group, there was greater electrical activity in the VLL than in the VMO. In both groups, there was greater electrical activity in the VMO and VLL than in the VLO. In the PFPS group, the MRI showed higher SA and lower CA values, and there was a negative correlation between the VMO and the PTA., Conclusion: The data suggest that, in individuals with PFPS, greater electrical activity in the VLL combined with an increased SA and a decreased CA may contribute to patellar instability.

Study Design: Case-control and reliability study., Objectives: To compare foot and ankle characteristics between individuals with and without patellofemoral pain syndrome (PFPS) and to identify reliable weight-bearing foot and ankle measurements for use in future research on PFPS., Background: PFPS is a common presentation to sports medicine and orthopaedic clinics. Characteristics of the foot and ankle are often linked with PFPS development, although evidence to support this link is equivocal and there is a lack of consensus on how best to evaluate these characteristics., Methods: A variety of weight-bearing foot and ankle measurements were evaluated by 3 raters of varying experience in 20 individuals with PFPS and 20 controls matched by age, sex, height, and body mass. Between-group comparisons were made for each measurement using data from an experienced podiatrist blinded to group assignment of the participants. Intrarater and interrater reliability was compared between all measurements using the first 15 participants from each group., Results: Between-group comparisons showed that the individuals in the PFPS group had a more pronated foot posture when assessed by the foot posture index and longitudinal arch angle, and for all measurements relative to subtalar joint neutral. Foot posture index, normalized navicular drop, and calcaneal angle relative to subtalar joint neutral measurements also possessed high reliability in both groups when used by experienced raters. Reliability was not influenced by rater experience or the presence of PFPS for relaxed-stance foot posture measurements. Both tester inexperience and the presence of PFPS reduced reliability for all measurements of foot posture relative to subtalar joint neutral and measurement of weight-bearing ankle dorsiflexion., Conclusion: The foot posture index, normalized navicular drop, and calcaneal angle relative to subtalar joint neutral are all reliable and sensitive to group differences when used in a population with PFPS. Individuals with PFPS possess a more pronated foot posture and increased foot mobility compared to controls. Prospective evaluation of these measurements is now required to determine whether they contribute to the development of PFPS. J Orthop Sports Phys Ther 2010;40(5):286-296, Epub 12 April 2010. doi:10.2519/jospt.2010.3227.

Study Design: Controlled laboratory study using a cross-sectional design., Objectives: To compare patellofemoral joint kinematics, femoral rotation, and patella rotation between females with patellofemoral pain (PFP) and pain-free controls using weight-bearing kinematic magnetic resonance imaging., Background: Recently, it has been recognized that patellofemoral malalignment may be the result of femoral motion as opposed to patella motion., Methods: Fifteen females with PFP and 15 pain-free females between the ages of 18 and 45 years participated in this study. Kinematic imaging of the patellofemoral joint was performed using a vertically open magnetic resonance imaging system. Axial-oblique images were obtained using a fast gradient-echo pulse sequence. Images were acquired at a rate of 1 image per second while subjects performed a single-limb squat. Measures of femur and patella rotation (relative to the image field of view), lateral patella tilt, and lateral patella displacement were made from images obtained at 45 degrees , 30 degrees , 15 degrees , and 0 degrees of knee flexion. Group differences were assessed using a mixed-model analysis of variance with repeated measures., Results: When compared to the control group, females with PFP demonstrated significantly greater lateral patella displacement at all angles evaluated and significantly greater lateral patella tilt at 30 degrees , 15 degrees , and 0 degrees of knee flexion. Similarly, greater medial femoral rotation was observed in the PFP group at 45 degrees , 15 degrees , and 0 degrees of knee flexion when compared to the control group. No group differences in patella rotation were found., Conclusion: Altered patellofemoral joint kinematics in females with PFP appears to be related to excessive medial femoral rotation, as opposed to lateral patella rotation. Our results suggest that the control of femur rotation may be important in restoring normal patellofemoral joint kinematics. J Orthop Sports Phys Ther 2010;40(5):277-285, Epub 12 March 2010. doi:10.2519/jospt.2010.3215.

Background: This diagnostic study was performed to determine the correlation between anterior knee pain and chondromalacia patellae and to define the reliability of magnetic resonance imaging for the diagnosis of chondromalacia patellae., Methods: Fifty-six young adults (median age, 19.5 years) with anterior knee pain had magnetic resonance imaging of the knee followed by arthroscopy. The patellar chondral lesions identified by magnetic resonance imaging were compared with the arthroscopic findings., Results: Arthroscopy confirmed the presence of chondromalacia patellae in twenty-five (45%) of the fifty-six knees, a synovial plica in twenty-five knees, a meniscal tear in four knees, and a femorotibial chondral lesion in four knees; normal anatomy was seen in six knees. No association was found between the severity of the chondromalacia patellae seen at arthroscopy and the clinical symptoms of anterior knee pain syndrome (p = 0.83). The positive predictive value for the ability of 1.0-T magnetic resonance imaging to detect chondromalacia patellae was 75% (95% confidence interval, 53% to 89%), the negative predictive value was 72% (95% confidence interval, 56% to 84%), the sensitivity was 60% (95% confidence interval, 41% to 77%), the specificity was 84% (95% confidence interval, 67% to 93%), and the diagnostic accuracy was 73% (95% confidence interval, 60% to 83%). The sensitivity was 13% (95% confidence interval, 2% to 49%) for grade-I lesions and 83% (95% confidence interval, 59% to 94%) for grade-II, III, or IV lesions., Conclusions: Chondromalacia patellae cannot be diagnosed on the basis of symptoms or with current physical examination methods. The present study demonstrated no correlation between the severity of chondromalacia patellae and the clinical symptoms of anterior knee pain syndrome. Thus, symptoms of anterior knee pain syndrome should not be used as an indication for knee arthroscopy. The sensitivity of 1.0-T magnetic resonance imaging was low for grade-I lesions but considerably higher for more severe (grade-II, III, or IV) lesions. Magnetic resonance imaging may be considered an accurate diagnostic tool for identification of more severe cases of chondromalacia patellae.

Background and Purpose: The optimal treatment for isolated patellofemoral osteoarthritis is unclear at present. We systematically reviewed the highest level of available evidence on the nonoperative and operative treatment of isolated patellofemoral osteoarthritis to develop an evidenced-based discussion of treatment options., Methods: A systematic computerized database search (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, MEDLINE (PubMed), and EMBASE) was performed in March 2009. The quality of the studies was assessed independently by two authors using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach., Results: We extracted data from 44 articles. The best available evidence for treatment of isolated patellofemoral osteoarthritis is sparse and of generally low methodological quality. Nonoperative treatment using physiotherapy (GRADE: high quality, weak recommendation for use), taping (GRADE: moderate quality, weak recommendation for use), or injection therapy (GRADE: very low quality, weak recommendation for use) may result in short-term relief. Joint-preserving surgical treatment may result in insufficient, unpredictable, or only short-term improvement (GRADE: low quality, weak recommendation against use). Total knee replacement with patellar resurfacing results in predictable and good, durable results (GRADE: low quality, weak recommendation for use). Outcome after patellofemoral arthroplasty in selected patients is good to excellent (GRADE: low quality, weak recommendation for use)., Interpretation: Methodologically good quality comparative studies, preferably using a patient-relevant outcome instrument, are needed to establish the optimal treatment strategy for patients with isolated patellofemoral osteoarthritis.

Unlabelled: The purpose of this study was to associate patellofemoral pain with the findings of arthroscopic procedures. A visual analogue scale was used considering that 1 represented no pain and 10 severe pain, the functional Lysholm scale for function, and the Outerbridge classification to determine the grade of the articular cartilage lesion., Material and Methods: The study population was composed of an heterogeneous group of patients with chondral lesions. This is a retrospective, observational and longitudinal study undertaken for a period of 18 months. Sixty-nine patients had patellofemoral pain, and traumatic knee injuries were excluded., Results: Sixty-eight patients were found to have a chondral lesion, only one patient did not. In the latter only loose body removal was performed. The most frequent procedure was articular lavage, debridement and chondroplasty in 98.5%. Thirty-five patients were found to have knee arthrosis grade IV (50.7%); the broadest functional improvement range occurred in patients with arthrosis grades I and III., Discussion: Patients with mild-to-moderate knee arthrosis grades I to III are the ones with the highest chance of success from the perspective of pain relief and functionality of arthroscopic surgery.

Patellofemoral pain syndrome (PFPS) is one of the most common, yet misunderstood, knee pathologies. PFPS is thought to result from abnormal patella tracking caused from altered neuromuscular control. Researchers have investigated neuromuscular influences from the gluteus medius (GM), vastus medialis (VM), and vastus lateralis (VL) but with inconsistent findings. A reason for these discrepancies may be from varying methodology. The purpose of this study was to determine the reliability of electromyographic (EMG) methods used to assess amplitudes and timing differences of the GM, VM, and VL in subjects with PFPS. Seven females with PFPS participated. GM, VM, and VL activity was assessed during the stance phase of a stair descent task on two separate occasions. Amplitudes during the different intervals of stance were recorded and expressed as a percent of each muscle's maximum voluntary isometric contraction. Muscle onsets at the beginning of stair descent were also determined. VM-GM, VL-GM, and VL-VM onset timing differences were quantified. Intraclass correlation coefficients (ICCs) and standard errors of measurement (SEMs) were calculated to assess between-day reliability. Most EMG measures had acceptable reliability (ICC(3,5)>or=0.70). Although some measures had moderate reliability (ICC<0.70), they had low SEMs, which suggested high measurement precision. These findings support using these methods for examining neuromuscular activity in subjects with PFPS.

Background: Patellofemoral pain syndrome (PFP) is a common musculoskeletal condition that has a tendency to become chronic and problematic in a proportion of affected individuals. The objective of this study was to identify prognostic factors that may have clinical utility in predicting poor outcome on measures of pain and function in individuals with PFP., Methods: A prospective follow-up study was conducted of 179 participants in a randomised clinical trial. Nine baseline factors (age, gender, body mass index, arch height, duration of knee pain, worst pain visual analogue scale, Kujala Patellofemoral Score (KPS), functional index questionnaire (FIQ), step down repetitions) were investigated for their prognostic ability on outcome assessed at six, 12 and 52 weeks (worst pain, KPS and FIQ). Factors with significant univariate associations were entered into multivariate linear regression models to identify a group of factors independently associated with poor outcome., Results: Long symptom duration was the most consistent predictor of poor outcome over 52 weeks rated on the KPS and the FIQ (beta-0.07, 95% confidence interval -0.1 to -0.03, p < 0.000; and -0.02, -0.03 to -0.01, p < 0.000, respectively). Worse KPS at baseline was predictive of outcome at six, 12 and 52 weeks. Gender, body mass index and arch height were generally not associated with outcome (univariate analysis), while age, worst pain, FIQ and step downs were excluded during multivariate analyses., Conclusions: Patients presenting with PFP of long duration who score worse on the KPS have a poorer prognosis, irrespective of age, gender and morphometry. These results suggest that strategies aimed at preventing chronicity of more severe PFP may optimise prognosis.

Patellofemoral pain syndrome (PFPS) is a common disorder that afflicts people across all age groups, and results in various degrees of knee pain. The diagnosis of PFPS is difficult since the exact biomechanical factors and the extent to which they are affected by the disorder are still unknown. Recent research has reported significant statistical differences in ground reaction forces (GRFs) and foot kinematics, which could be indicative of PFPS, but the interrelationship between many of these measures and the pathology have been absent so far. In this paper, we applied the support vector machines (SVMs) to detect PFPS gait based on 14 GRF and 16 foot kinematic features recorded from 27 subjects (14 healthy and 13 with PFPS). The influence of combined gait parameters on classification performance was investigated through the use of a feature-selection algorithm. The optimal feature set was then compared against the most statistically significant individual features (p < 0.05) found by previous study. Test results indicated that GRF features alone resulted in a higher leave-one-out (LOO) classification accuracy (85.15%) compared to 74.07% using only kinematic features. A hill-climbing feature-selection algorithm was applied to determine the subset of combined kinematic and kinetic features, which provided optimal classifier performance. This subset, which consists of six features (two from GRF and four from foot kinematic features), provided an improved LOO accuracy of 88.89% . The optimal feature set detected by the SVM, which best identified gait characteristics of PFPS, was found to be closely related to inferential statistical analysis with the added distinction that the SVM could potentially be deployed as an automated system for detecting gait changes in patients with PFPS.

Objective: The purpose of this pilot study was to determine the feasibility of (1) using the existing clinic, clinicians, interns, faculty, and staff from our college in conducting all components of a planned randomized controlled clinical trial; (2) successfully recruiting patients with patellofemoral pain syndrome (PFPS); and (3) consistently, effectively, and safely implementing the study protocols and therapy., Methods: Diagnostic, treatment, and blind assessment procedures were carried out while recruitment and administrative techniques for managing long-term storage of data and files were developed. Thirty-one patients were randomized into a local manipulative group (group A) or to a full kinetic chain manipulative therapy group (group B), each combined with exercise and soft tissue treatment. The Anterior Knee Pain Scale, visual analog scale, and Patient Satisfaction Scale were used., Results: All phases of the feasibility study including use of the clinic, staff, recruitment techniques, treatment protocols, data collection, input, and analysis were effectively and safely carried out., Conclusions: A feasibility study investigating the ability to conduct a randomized controlled trial of a manipulative therapy protocol for PFPS using available chiropractic college infrastructure was accomplished. A fully powered PFPS trial is feasible and merited.

Medio-lateral patellar position is regarded as a sign of patellofemoral pain syndrome and patellar instability. Its assessment is important in accurately performing patellofemoral therapeutic taping techniques. The purpose of this paper is to systematically review the literature to determine the reliability and validity of evaluating medio-lateral patellar position. An electronic database search was performed accessing AMED, British Nursing Index, CINAHL, the Cochrane database, EMBASE, Ovid Medline, Physiotherapy Evidence Database (PEDro), PubMed and Zetoc to July 2008. Conference proceedings and grey literature were also scrutinised for future publications. All human subject, clinical trials, assessing the inter- or intra-tester reliability, or the criterion validity, were included. A CASP tool was employed to evaluate methodological quality. Nine papers including 237 patients (306 knees) were reviewed. The findings of this review suggest that the intra-tester reliability of assessing medio-lateral patellar position is good, but that inter-tester reliability is variable. The criterion validity of this test is at worse moderate. These are based on a limited evidence-base. Further study is recommended to compare the McConnell (1986) [McConnell J. The management of chondromalacia patellae: a long term solution. Australian Journal of Physiotherapy 1986;32(4):215-23] and Herrington (2002) [Herrington LC. The inter-tester reliability of a clinical measurement used to determine the medial/lateral orientation of the patella. Manual Therapy 2002;7(3):163-7] methods of assessing medio-lateral patellar position in patients with well-defined patellofemoral disorders.

Study Design: Resident's case problem., Background: Kaposi's sarcoma (KS) is the most common form of cancer in patients with human immunodeficiency virus (HIV) infection. Although KS is often initially asymptomatic, this neoplasm may progress to affect multiple organ systems, including structures of the musculoskeletal system, which can produce symptoms similar to those associated with common orthopaedic conditions. This resident's case problem describes the evaluation and differential diagnosis of a 45-year-old male with HIV and KS, referred to physical therapy with an initial diagnosis of radiographic osteoarthritis (OA) and patellofemoral pain syndrome (PFPS) of the left knee. His primary complaint was knee pain during end range knee flexion., Diagnosis: The history, systems review, and examination suggested a source of pain of a nonorthopaedic origin. Differential examination ruled out clinical OA, PFPS, ligament/cartilage derangement, and tendonitis. Avascular necrosis of the medial femoral condyle was also considered as a possible source of pain. Recent blood tests indicated a high viral load and low CD4 count, which might have increased susceptibility to opportunistic infections or KS tumor progression. The patient was referred back to his physician for additional follow-up. Magnetic resonance imaging (MRI) of the knees were consistent with a systemic inflammatory process such as KS. A true-cut biopsy was subsequently scheduled, which confirmed KS lesions at the left knee., Discussion: Physical therapists who manage orthopaedic conditions should be aware of the disablement that may result from acquired immunodeficiency syndrome-related KS. A thorough joint-specific examination, with a broad differential diagnosis, should be employed for patients having known systemic diseases., Level of Evidence: Differential diagnosis, level 4.

Purpose and Method: In this literature review, relevant studies on electromyographic (EMG) onset timing of vastus medialis obliquus and vastus lateralis in people with and without patellofemoral pain syndrome (PFPS) were reviewed and discussed., Conclusion: Studies had used diverse EMG signal processing and testing protocols, also only a half of their findings tended to support the notion that detection of EMG onset of the vastii muscles is diagnostically useful for identifying subjects with PFPS.

Tight lateral structures have been implicated in subjects presenting with patellofemoral pain syndrome (PFPS). It has been proposed that a tight iliotibial band (ITB) through its attachment of the lateral retinaculum into the patella could cause lateral patella tracking, patella tilt and compression. Twelve subjects presenting with PFPS were compared with 12 matched control subjects. Hip adduction was measured using the Ober test in each subject as an indirect measure of ITB length. The mean values for hip adduction in the control group were 21.4 (+/-4.9) and 20.3 (+/-3.8) degrees in the left and right legs, respectively, and in the PFPS group, 17.3 (+/-6.1) and 14.9 (+/-4.2) degrees in the non-painful leg and painful leg, respectively. One way analysis of variance (ANOVA) revealed a highly significant difference between groups (F=4.485, p=0.008) and post-hoc analysis showed a significant difference between the painful leg in the PFPS group and the left and right legs in the control group, p=0.002 and 0.009, respectively. The results from this study show that subjects presenting with PFPS do have a tighter ITB. Future work should investigate this observation prospectively in order to determine whether a tight ITB is the cause or effect of PFPS.

Introduction: Imbalanced soft tissue tension between medial and lateral para-patellar structures is the most common pathogenic cause of patellar malalignment syndrome. Despite the fact that an effective technique has not been developed, this disorder is usually treated conservatively. This prospective study tried to identify an effective alternative treatment for patellar malalignment syndrome., Materials and Methods: Forty female patients (age, 20-40 years) with bilateral patellar malalignment syndrome were randomly divided into two groups. Forty knees in 20 patients were treated with goosestep training without forcefully striking the ground, and 40 knees in other 20 patients were treated with goosestep training with forcefully striking the ground., Results: After 1 month, significant clinical improvement was observed in 72.5% of all patients (P < 0.001). Congruence or lateral patellofemoral angles and VMO/VL (vastus medialis obliquus/vastus lateralis) ratio significantly improved within 1 or 3 months in both groups (P < 0.001 for each comparison)., Conclusion: Goosestep training with or without forcefully striking the ground is a feasible method for treating patellar malalignment syndrome. The main advantages include its convenience, simplicity, lack of cost, and demonstrated effectiveness.

Anterior knee pain syndrome is extremely common in the military and has previously often led to medical discharge. The Patellofemoral Pain Group programme of exercises developed at the Defence Medical Rehabilitation Centre at Headley Court has become the first line treatment strategy for this problem in the military. The introduction of this low level, impact free, progressive exercise programme at the Regional Rehabilitation Unit in Gutersloh has also proved useful, leading to improvements in employability of affected soldiers and reduction in symptoms.

PFS is one of the most common orthopedic problems. As long as overloading and malalignment of the knee is occurring, the patient will continue to experience pain. A proper understanding of anatomy and biomechanics of the knee is critical for an accurate diagnosis and treatment plan. As with most medical problems, a detailed history and physical examination help determine the proper treatment. Radiographs and CT can aid in diagnosis and treatment. NSAIDs, physical therapy, and HA therapy can prevent the need for surgical intervention in 80% to 90% of patients.

The quadriceps or Q-angle is an index of the vector for the combined pull of the extensor mechanisms and the patellar tendon. It is used as an indicator for patellofemoral joint dysfunction. The purpose of this article is to systematically review and appraise the literature to determine the reliability and validity of this test. An electronic database search was performed accessing AMED, British Nursing Index, CINAHL, the Cochrane database, EMBASE, ovid Medline, Physiotherapy Evidence Database (PEDro), PsycINFO, Pubmed and Zetoc to April 2008. All English language, human subject, clinical trials, assessing the inter- or intra-tester reliability, or the criterion validity, were included. The Critical Appraisal Skills Programme appraisal tool was used to establish the methodological quality of each study. Ten articles including 569 control and 179 patellofemoral disorder knees were reviewed. The findings suggest that there is considerable disagreement on the reliability and validity of the clinical Q-angle measurement. This may be due to a lack of standardisation in the measurement procedure. Further study is advocated to re-evaluate this topic using well-designed, and sufficiently large observational studies of specific patellofemoral dysfunction populations.

It may be very difficult to diagnose the pathology in patients with anterior knee pain. Patients with chronic anterior knee pain have been reviewed for the study. Our aim was to delineate the presence of subtle trochlear dysplasia by measuring lateral trochlear inclination (LTI) in axial magnetic resonance imaging (MRI) scans. While there were 109 knees in the study group with anterior knee pain (AKP), control group consisted of 74 knees without AKP. The LTI measurements were performed at the level of proximal cartilaginous area of trochlear groove in axial scans. The condition was termed to be trochlear dysplasia when LTI was below 11 masculine. Parameters in both groups were statistically analyzed and compared for their association with LTI. There was no significant difference between LTI values of male and female subjects in each group. The mean LTI values in anterior knee pain and control groups were 17.32 masculine and 21.5 masculine, respectively, and the difference was statistically significant (P < 0.05). The ratio of knees with trochlear dysplasia was 16.5% in AKP group, which was only 2.7% in control. In the AKP group, the ratio of trochlear dysplasia was significantly high (P < 0.05). Although trochlear dysplasia has been generally detected in cases with patellar instability, this study revealed that the frequency of this finding in patients with other causes of anterior knee pain was also considerably high. Measurement of lateral trochlear inclination in axial MRI scans with radiologic assessment seems to be a valuable diagnostic criterion, especially in patients in whom etiology of anterior knee pain could not be identified.

Patellofemoral arthroplasty (PFA) has been an option for patients with symptomatic patellofemoral osteoarthritis since the 1950's. Many of the early failures resulted from a combination of implant design and surgeon technique. The goal of this overview is not to review the history of PFA, but rather to explore options for surgeons to optimize long-term outcomes and improve patient knee function, while highlighting the differing techniques required in PFA with those routinely adopted in total knee arthroplasty (TKA).

Lesions in the patellofemoral region can be caused by trauma, chronic overloading, and especially regarding cartilage alterations by normal aging or pathologic processes. Very commonly these lesions lead to early arthrosis. An accurate clinical evaluation in all these patients is recommended. The combination of clinical information and radiological examinations should end up with an exact diagnosis.As part of the radiological evaluation of complaints of the patellofemoral region MR imaging is of special value since this method allows direct visualization of all intra- and extra-articular structures and their alterations, ultimately aiding in planning sufficient therapy. Moreover, is it possible to exclude pathology by MR imaging, which helps to prevent useless treatment and surgical procedures.

Patellofemoral pain and instability account for 25% of all sports-related knee problems. However, definitive analysis seems to be difficult. Descriptive findings like "anterior knee pain", "patellofemoral pain syndrome", or "chondromalacia" are used instead of diagnosis. One reason may be the complex pathomechanics of the patellofemoral joint which is suspended between the pelvis, the femur, and the tibia and subsequently is influenced by the whole lower extremity from the hip down to the foot. On the other hand, different signs and functional tests are in use with at times lack of quantification and ambiguous interpretation. The current manuscript reviews the commonly used signs and functional tests, analyzes them based on the current literature, and arranges them in a practical manner for physical examination. A MEDLINE literature search and special textbooks regarding patellofemoral disorders were used; 43 signs and tests were found. The examiner can quantify 18 of these findings on a nominal and 15 on an ordinal scale. Thus, this manuscript provides a standardized algorithm for physical examination with a collection of quantifiable findings, which are of growing importance to justify adequate diagnostics and treatment.

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 masculine (+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.

Objective: There is no consensus among experts regarding the etiology or management of patellofemoral pain syndrome (PFPS). Observations indicating dysfunction of the peripheral nervous system around the patellae have been reported. To what extent these sensory abnormalities cause pain has so far not been investigated. The aim of this study was to assess whether a subgroup of patients with unilateral PFPS have neuropathic pain related to the painful knee., Method: A total of 91 patients with unilateral PFPS, between 18 and 40 years of age, and a comparable group of 23 healthy participants aged 18 to 44 years were included. Level of knee function, pain intensity, and qualities were assessed. Somatosensory assessments were carried out by bedside neurologic tests and quantitative sensory testing, assessing thermal, tactile, and vibration thresholds., Results: Ample signs of sensory aberrations with considerable heterogeneity and overlap regarding the degree and type of dysfunction of the nervous system were found in the painful area of the PFPS patients. No clear subgroup of patients with neuropathic pain or clustering of features related to neuropathic pain was identified., Discussion: This study hypothesizes that the observed sensory aberrations may cause neuropathic pain in patients with PFPS. There is no validated method for subgrouping patients with possible neuropathic pain and in this study considerable heterogeneity and overlap regarding signs and symptoms of neuropathic pain made subgrouping even more difficult. A mechanism-based understanding of the pain is, however, essential for the selection of adequate treatment strategies in painful musculoskeletal disorders.

Study Design: Cross-sectional matched-pairs design., Objective: To investigate if differences existed in the medio-lateral position of the patella between subjects with patellofemoral pain (PFP) and matched controls., Background: The assessment of patella position is often proposed as an essential aspect of clinical examination of individuals with PFP. To date, only 1 clinical method of assessing lateral patella position has been intensively investigated. Although there is a growing body of evidence on the reliability and validity of this method, no studies have investigated differences in patella position between patients with PFP and controls., Methods and Measures: Twelve female patients with PFP and 12 matched controls (mean +/- SD age, 21.9 +/- 2.6) had their medio-lateral patella position assessed in 20 masculine of flexion. Differences between groups were investigated with independent-groups t tests., Results: All subjects were found to have a laterally located patella. The mean +/- SD lateral position for the individuals in the PFP group was 7.5 +/- 2.6 mm compared to 3.8 +/- 2.4 mm for the control group. This difference was statistically significant (P = .019). Intratester reliability of the measurement of patellar position, calculated using intraclass correlation model 3,1, was 0.86., Conclusion: Using this method of assessing patella position, the patella of individuals with PFP was significantly more laterally located than the patella of those in a matched control group.

Objective: To investigate acute anterior knee pain caused by overuse in terms of pain location, aggravating activities, findings on clinical examination and ultrasound/MRI examination. To determine if acute anterior knee pain caused by overuse should be classified as a subgroup of patellofemoral pain syndrome (PFPS)., Methods: In a observational study design 30 army recruits with anterior knee pain (mean duration of pain 4 weeks) were examined using the PFPS pain severity scale (PSS), knee pain diagrams, standardised clinical examination, ultrasound and MRI examinations., Results: On PSS typical knee loading activities were the most painful, while sitting with knee bend for prolonged time caused surprisingly little pain. Pain was most commonly perceived in the peripatellar area (25 patients (83%)). The most common site of pain on clinical examination was the peripatellar area (25 patients (83%)), but other synovial covered structures including the fat pad of Hoffa (12 patients (40%)), the medial plica and the joint line (12 patients (40%)) were also involved. Only eight patients (27%) experienced pain on the patellofemoral compression test. Only discrete changes was detected on MRI/ultrasound., Conclusions: Acute anterior knee pain should be regarded as a subgroup of PFPS as both symptoms and clinical examination suggests this. The clinical examination with disseminated pain in all synovial covered structures is consistent with ideas of the importance of synovium in the genesis of pain.

The last three decades have witnessed a tremendous increase in female sports participation at all levels. However, increased sports participation of female athletes has also increased the incidence of sport-related injuries, which can be either acute trauma or overuse injuries. Overuse injuries may be defined as an imbalance caused by overly intensive training and inadequate recovery, which subsequently leads to a breakdown in tissue reparative mechanisms. This article will review the most frequent overuse injuries in female athletes in the context of anatomical, physiological, and psychological differences between genders.

Background: Anterior knee pain without clinical and radiologic abnormalities has primarily been explained from a purely structural view. A recently proposed biologic and homeostatic explanation questions the malalignment theory. No objective measurement of the pathophysiology responsible for changes in local homeostasis has been presented., Hypothesis: Flexing the knee joint interferes with the perfusion of the patellar bone in patellofemoral pain syndrome., Study Design: Case control study; Level of evidence, 4., Methods: Pulsatile blood flow in the patella was measured continuously and noninvasively using photoplethysmography. Measurements were made with the patient in a resting position with knee flexion of 20 degrees and after passive knee flexion to 90 degrees. In total, 22 patients with patellofemoral pain syndrome were examined bilaterally, and 33 subjects with healthy knees served as controls., Results: The pulsatile blood flow in the patient group decreased after passive knee flexion from 20 degrees to 90 degrees (systematic change in position, or relative position [RP] = -0.32; 95% confidence interval for RP, -0.48 to -0.17), while the response in the control group showed no distinct pattern (RP = 0.17; 95% confidence interval for RP, -0.05 to 0.31). The difference between the groups was significant (P = .0002). The median change in patients was -26% (interquartile range, 37)., Conclusions: Pulsatile patellar blood flow in patellofemoral pain syndrome patients is markedly reduced when the knee is being flexed, which supports the previous notion of an ischemic mechanism involved in the pathogenesis of this pain syndrome.

Study Design: Observational, cohort study., Objectives: To test the hypothesis that patellar alignment and tibiofemoral rotation alignment explain unique portions of variance in patellofemoral joint contact area in individuals with patellofemoral pain (PFP) and in pain-free control subjects., Background: PFP has been proposed to result from increased patellofemoral joint stress due to decreased contact area. Patellar malalignment (lateral displacement and tilt) is believed to be the main contributor to decreased contact area. Recent studies suggest that transverse plane rotation of the femur and/or tibia may also contribute to decreased contact area., Methods and Measures: Twenty-one subjects with PFP (16 female, 5 male) and 21 pain-free subjects (14 female, 7 male) participated. Subjects underwent magnetic resonance imaging with the knee in full extension and the quadriceps contracted. Measures of patellofemoral joint contact area, lateral patellar displacement, patellar tilt angle, tibiofemoral rotation angle, and patellar width were obtained. Hierarchical multiple regression analyses were performed for each group using contact area as the dependent variable. The order of independent variables was patellar width, patellar tilt angle, and tibiofemoral rotation angle. To avoid multicolinearity, lateral patellar displacement was not included., Results: In the PFP group, patellar width and tibiofemoral rotation angle explained 46% of the variance in contact area. In pain-free subjects, patellar width was the only predictor of contact area, explaining 31% of its variance. Patellar tilt angle did not predict contact area in either group., Conclusion: Addressing factors that control tibiofemoral rotation may be indicated to increase contact area and reduce pain in individuals with PFP. Future studies should investigate the contributions of patellar alignment and tibiofemoral rotation to patellofemoral joint contact area at a variety of knee flexion angles.

Patello-femoral pain syndrome (PFPS) is a common knee joint disability. The integration of hip soft tissue regimens are not always emphasized, although current literature implies that there is a significant relationship between the two and there is a lack of randomized clinical trials to substantiate this relationship in clinical practice. A randomized controlled assessor blinded trial was designed to explore different rehabilitation programs related to PFPS. The study was conducted at RAZIEL institute of physical therapy, Netania, Israel with a total of 30 consecutive patients (mean age 35y), diagnosed with PFPS. All patients were randomly allocated into 3 groups. Group I conventional knee rehabilitation program. Included quadriceps strengthening and Trans Electric Neuromuscular Stimulation (TENS). Group II hip oriented rehabilitation program. included stretching, Hip external rotators strengthening and TENS. Group III a combination of the two above programs. Pain and function were documented on initial of the program and again 3 weeks later, on the completion. Pain was assessed by a numeric visual analogue scale (VAS); function was assessed by Patello-femoral joint evaluation scale (PFJES) (0-100 points). At end of trial, all groups showed significant improvements in VAS and PFJES (p<0.0001); these improvements did not vary significantly between the 3 groups. The conclusions were that the explored different rehabilitation programs showed a similar beneficial effect.

Background: Anterior knee pain, diagnosed as Patellofemoral Pain Syndrome (PFPS), is one of the most common musculoskeletal problems found in adolescents and young adults. There is no consensus in medical literature concerning the aetiology of the PFPS., Aims: To assess by means of Quantitative Sensory Testing (QST) whether patients suffering from long-lasting unilateral PFPS demonstrate somatosensory dysfunction related to afferent fibres from the local pain area., Methods: A descriptive non-experimental study with two independent samples, consisting of 25 men and women between 18 and 44 years of age with unilateral PFPS, and a comparable group of 23 healthy subjects. Somedic Thermotest apparatus was used to assess thresholds of thermal perception, and of heat and cold pain thresholds. Von Frey filaments were used to detect tactile sensitivity. Furthermore, quality and intensity of knee pain, symptoms and signs from a clinical neurological examination were recorded., Results: Decreased sensitivity to tactile stimulation, when tested with von Frey filaments, was demonstrated on both the painful and pain-free knee in subjects with PFPS, compared to the mean between the knees of the control group (p< or =0.001). The mean detection threshold for warmth was increased by 1.9 degrees C (p< or =0.01) in the painful knee, and 1.4 degrees C (p< or =0.01) in the non-painful knee in the PFPS group, compared to the mean of the healthy control group. The mean detection threshold for cold was increased by 1.6 degrees C (p< or =0.01) in the painful knee of the PFPS group, compared to the control group. These findings were supported by clinical sensory tests. No significant differences of mean thermal pain thresholds between the PFPS group and controls were found, and there were no significant differences in mean detection thresholds for warmth, cold or thermal pain thresholds between the painful and the non-painful knees in the PFPS group., Conclusion: This study demonstrated an abnormal sensory function in the painful and non-painful knee in some individuals with long lasting unilateral Patellofemoral Pain Syndrome using Quantitative Sensory Testing supported by clinical neurological examinations. A dysfunction of the peripheral and/or the central nervous system may cause neuropathic pain in some subjects with PFPS.

Patellar taping is regarded as an important element of the treatment of patellofemoral joint pain. Key to the successful use of patellar taping is the assessment of patella position. The reliability and validity of the techniques used to assess patella position has been questioned. The aim of the study was to assess the validity of the clinical assessment technique of patella medio-lateral position and patella lateral tilt against the criterion measure of MRI. Twenty-four subjects eight females and 16 males had their patella position examined in the study (mean age 24.5+/-7.9 years, range 18-42 years). The study also assessed intra-tester reliability of the technique. A good correlation was found between the findings of the clinical test for medio-lateral position and the MRI measure (r=0.611, p=0.002). All of the subjects found to have a laterally tilted patella on clinical examination had a lateral patella tilt defined by PTA of greater than 5 degrees . Those subjects with a PTA of less than 5 degrees on clinical examination were assessed as having no degree of patella tilt. The study undertaken shows that when undertaken by an experienced manual therapist positional assessment of the patella can have strong criterion validity and intra-tester reliability.

Anterior knee-pain syndrome would best be defined as a painful condition that arises in or around the patellofemoral joint and is insidious in onset and bilateral, with no macroscopic gross pathology. Anterior knee pain as a descriptive term would define the need to search further for a specific cause of pain, because neither patellar cartilage damage nor malalignment would necessarily be correlated to pain. The examining physician should be aware that specifically in adolescents the higher chance would be that, eventually, no clear-cut pathology would be found; thus, great caution should be taken before diagnosing anterior knee-pain syndrome as existing unilaterally. It could be claimed, following the above, that as opposed to the term "anterior knee pain," the term "anterior knee-pain syndrome" is an exclusion diagnosis that can be applied after macroscopic pathology has been ruled out.

Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.

Patellofemoral pain syndrome (PFPS) is a common disorder resulting in varying degrees of knee pain. The diagnosis of PFPS is difficult since the exact biomechanical factors involved in the disorder are still unknown. Recent research has reported significant differences in rearfoot kinematics and foot ground reaction forces (GRFs) which could be indicative of PFPS, but the inter relationship between these measures and the pathology have been inconclusive so far. In this paper, we investigate Support Vector Machines (SVM)'s potential to classify gait patterns with PFPS using 14 GRF and 16 rearfoot kinematic features. Test results indicated that using GRF features alone resulted in a leave one out (LOO) classification accuracy of 85.15% compared to 74.07% using kinematic features. A hill climbing feature selection algorithm was subsequently applied to determine the subset of features which improved classifier performance. This reduced subset consisted of 6 features from a combination of GRFs and kinematic features, and provided a maximum LOO accuracy of 88.89% in detecting the PFPS gait.

Background: Patellofemoral pain syndrome is a descriptive term applied to patients with nonspecific anterior knee pain, and is the most common knee problem. The pain in most patellofemoral disorders is generalized to the anterior part of the knee. One important concept in patellofemoral joint function is the quadriceps angle (Q-angle). Theoretically, a higher Q-angle increases the lateral pull of the quadriceps femoris muscle on the patella and potentiates patellofemoral disorders. This study was undertaken to evaluate the relationship between the anterior knee pain and Q-angle., Methods: This prospective study was performed on two groups; the case group consisted of 100 outpatients (44 men, and 56 women) aged between 15 and 35 years, with anterior knee pain. The control group consisted of 100 outpatients (50 men, and 50 women) with the same age distribution, who presented with different problems in the upper extremities and no knee problems. The Q-angle of each knee was measured in all participants, using a universal goniometer., Results: The mean Q-angle for men, women, and all participants in the case group was 15.2, 20.1, and 18.0 degrees, respectively. In the normal control group the angles were 12.1, 16.7, and 14.9 degrees, respectively. All these differences were statistically significant (P < 0.001)., Conclusion: These results substantiate the fact that patients with anterior knee pain have larger Q-angles than healthy individuals.

Data regarding validity of clinical and radiographic findings in diagnosing patellofemoral pain syndrome are inconclusive. We prospectively assessed how sensitive and specific key patellofemoral physical examination tests are, and evaluated the prevalence of physical examination and radiographic findings. Sixty-one infantry soldiers with patellofemoral pain syndrome and 25 control subjects were evaluated. The sensitivity of the patellar tilt, active instability, patella alta, and apprehension tests was low (less than 50%); specificity ranged between 72% and 100%. Although the prevalence of positive patellar tilt and active instability tests was significantly greater in subjects with patellofemoral pain syndrome, there were no significant differences between the groups in the results of the other two tests. Soldiers with patellofemoral pain syndrome presented with increased quadriceps angle, lateral and medial retinacular tenderness, patellofemoral crepitation, squinting patella, and reduced mobility of the patella. There were no differences between the groups in the prevalence of lower limb and foot posture alignment and knee effusion. Plain radiography showed increased patellar subluxation in soldiers with patellofemoral pain syndrome. Other radiographic measures (sulcus angle, Laurin angle, Merchant angle, and Insall-Salvati index) were similar in both groups. We provide evidence regarding the validity of clinical and radiographic features commonly used for diagnosing patellofemoral pain syndrome. Physical examinations were more useful than plain radiography.

Patellar misalignment is more common than usually supposed; many patients learn to live with this affection without seeing a doctor. A large number of open surgical procedures were described for treatment of misalignment of extensor mechanism of knee. We want to present our method which consisted in arthroscopic lateral release and augmentation of medial retinaculum. We had 47 patients with femoro-patellar misalignment treated with this method. The results were appreciated by clinical and radiological criteria (patellar glide test, patellar tilt test, Macnab scores, Merchant angle). The follow-up was two years. Only 17% had recurrence of clinical signs.

The purpose of this study was to investigate the effect of increasing the number of test trials in the assessment of knee joint position sense, in a group of patellofemoral patients, and second, to investigate the effects of joint angle and type of test. Thirty-two patients with a diagnosis of patellofemoral pain syndrome were admitted to this study. Knee joint position sense was measured by performing an ipsilateral matching activity at target angles of 20 degrees and 60 degrees using two techniques; Passive Angle Reproduction (PAR), and Active Angle Reproduction (AAR). The results show that five repetitions are required for AAR and six for PAR. A two-way repeated-measures ANOVA showed that there was no significant difference (p = 0.559) in the accuracy of angle reproduction for the two angles (60 degrees and 20 degrees ); however, there was a significant difference (p = 0.001) between the two types of test (AAR and PAR). The results of this study have implications for clinicians and researchers who examine knee joint proprioception as part of functional assessment in a variety of knee joint pathologies including PFPS. A "quick" one-off assessment of knee joint position sense may give erroneous data; subjects need to have several trials before a true picture of their proprioceptive status emerges. Type of testing performed, active or passive, is also important, although the angle of testing may not be relevant., ((c) 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Patellofemoral pain syndrome (PFPS) is one of the most common musculoskeletal disorders. However, no consensus on the definition, classification, assessment, diagnosis, or management has been reached. We evaluated symptoms and clinical findings in subgroups of individuals with PFPS, classified on the basis of the findings in radiological examinations and compared the findings with knee-healthy subjects. An orthopedic surgeon and a physical therapist consecutively examined 80 patients clinically diagnosed as having PFPS and referred for physical therapy. The examination consisted of taking a case history and clinical tests. Radiography revealed pathology in 15 patients, and scintigraphic examination revealed focal uptake in 2 patients indicating pathology (group C). Diffusely increased uptake was present in 29 patients (group B). In the remaining 29 patients radiographic and scintigraphic examinations were normal (group A). Knee-healthy controls (group D) reported no clinical symptoms. No symptom could be statistically demonstrated to differ between the three patient groups. Knee-healthy subjects differed significantly from the three patient groups in all clinical tests measuring pain in response to the provocations; compression test, medial and lateral tenderness, passive gliding of the patella, but they also differed in Q angle. Differences in clinical tests between the patient groups were nonsignificant. The main finding in our study on patients clinically diagnosed with PFPS is that possible pathologies cannot be detected from the patient's history or from commonly used clinical tests.

Background: The reliability and measurement error of several impairment measures used during the clinical examination of patients with patellofemoral pain syndrome (PFPS) has not been established. The purpose was to determine the inter-tester reliability and measurement error of measures of impairments associated with PFPS in patients with PFPS., Methods: A single group repeated measures design was used. Two pairs of physical therapists participated in data collection. Examiners were blinded to each others' measurements., Results: Thirty patients (age 29 +/- 8; 17 female) with PFPS participated in this study. Inter-tester reliability coefficients were substantial for measures of hamstrings, quadriceps, plantarflexors, and ITB/TFL complex length, hip abductors strength, and foot pronation (ICCs from .85 to .97); moderate for measures of Q-angle, tibial torsion, hip external rotation strength, lateral retinacular tightness, and quality of movement during a step down task (ICCs from .67 to .79); and poor for femoral anteversion (ICC of .45). Standard error of measurement (SEM) for measures of muscle length ranged from 1.6 degrees to 4.3 degrees. SEM for Q-angle, tibial torsion, and femoral anteversion were 2.4 degrees, 2.9 degrees, and 4.5 degrees respectively. SEM for foot pronation was 1 mm. SEM for measures of muscle strength was 1.8 Kg for abduction and 2.4 Kg for external rotation., Conclusion: Several of the impairments associated with PFPS had sufficient reliability and low measurement error. Further investigation is needed to test if these impairment measurements are related to physical function and whether or not they are useful for decision-making.