Patellofemoral joint contact area is influenced by tibiofemoral rotation alignment in individuals who have patellofemoral pain

Kinematic gait characteristics associated with patellofemoral pain syndrome: a systematic review

Development of patellofemoral pain syndrome (PFPS) is considered to be multifactorial. The aims of this systematic review were to (i) summarise and critique the body of literature addressing kinematic gait characteristics associated with PFPS; and (ii) provide recommendations for future research addressing kinematic gait characteristics associated with PFPS. A comprehensive search of MEDLINE, EMBASE, CINAHL, and Current Contents revealed 561 citations for review. Each citation was assessed for inclusion and quality using a modified version of the 'Quality Index' and a novel inclusion/exclusion criteria checklist by two independent reviewers. A total of 24 studies were identified. No prospective studies with adequate data to complete effect size calculations were found. Quality of included case-control studies varied, with a number of methodological issues identified. Heterogeneity between studies made meta-analysis inappropriate. Reductions in gait velocity were indicated during walking, ramp negotiation, and stair negotiation in individuals with PFPS. Findings indicated delayed timing of peak rearfoot eversion and increased rearfoot eversion at heel strike transient during walking; and delayed timing of peak rearfoot eversion, increased rearfoot eversion at heel strike, reduced rearfoot eversion range, greater knee external rotation at peak knee extension moment, and greater hip adduction during running in individuals with PFPS. There is a clear need for prospective evaluation of kinematic gait characteristics in a PFPS population to distinguish between cause and effect. Where possible, future PFPS case-control studies should consider evaluating kinematics of the knee, hip and foot/ankle simultaneously with larger participant numbers. Completing between sex comparisons when practical and considering spatiotemporal gait characteristics during methodological design and data analysis is also recommended.

Patterns of patellofemoral articular cartilage wear in cadavers

STUDY DESIGN

Descriptive.

OBJECTIVE

Describe and compare patellar and femoral condylar wear patterns, and the wear frequency of both, relative to each other, gender, and sidedness.

BACKGROUND

Studies on normal and pathological patellar cartilage and patellofemoral joint biomechanics are plentiful. However, patellar wear patterns are undefined, as is the relationship of patellar to femoral condylar wear.

METHODS

Articular wear was described for 50 patellae and matching femurs from 26 cadavers. Wear locations were transcribed to gridded templates, and these were compared graphically for frequency, gender, and sidedness of wear. The percent frequency of wear was calculated and areas of wear described.

RESULTS

Three patellar and 2 femoral types of wear patterns were observed, and 12 areas of patellar wear and 3 areas of femoral wear described. Patella wear was along the horizontal middle of the patella, with marked medial and odd facet wear. Femoral wear was on the anterior and posterior aspects of the medial condyle, and posterior aspect of the lateral femoral condyle. Patellar and femoral wear frequencies were similar bilaterally, but patellar wear may differ with gender.

CONCLUSIONS

Patella and distal femur showed distinct wear patterns. The wear area under the patella matches the contact area between the patella and distal femur normally occurring between 45 degrees to 90 degrees of knee flexion. Patellofemoral assessment and treatment may differ for the aged population because of mechanical changes due to wear.

Utility of the frontal plane projection angle in females with patellofemoral pain

STUDY DESIGN

Case-control study of females with patellofemoral pain syndrome (PFPS) and a control group.

OBJECTIVES

Three different approaches were used to examine the utility of a 2-dimensional (2-D) frontal plane projection angle (FPPA) measure of knee alignment. First, we measured the FPPA association with respect to 3-dimensional (3-D) lower extremity joint rotations during single-leg squats. Second, we determined the correlation of the FPPA during single-leg squats with hip and knee joint rotations during running and single leg jumping. Third, we compared the FPPA between females with and without PFPS.

BACKGROUND

PFPS is associated with altered lower extremity kinematics during weight-bearing activities that decrease retropatellar contact area and increase retropatellar stress. An objective and simple procedure to quantify altered kinematics during weight-bearing activities may help clinicians identify individuals who may likely benefit from interventions to improve lower extremity kinematics.

METHODS AND MEASURES

Twenty females with PFPS and 20 healthy female controls performed single-leg squats, running, and repetitive single-leg jumps while 3-D lower extremity kinematics were recorded. The FPPA was recorded by a digital camera during single-leg stance and single-leg squats. Correlation coefficients were used to quantify the association between the FPPA and transverse and frontal plane hip and knee angles for all activities. Independent t tests were used to compare FPPA values between groups.

RESULTS

FPPA values representing medial displacement of the knee during single-leg squats were associated with increased hip adduction (r = 0.32 to 0.38, P<.044) and knee external rotation (r = 0.48 to 0.55, P<.001) across activities. FPPA values for the PFPS group reveal greater medial displacement of the knee compared with those of the control group during single-leg squats (P = .012).

CONCLUSION

The association between the FPPA and lower extremity kinematics that are associated with PFPS suggest that the FPPA during single-leg squats may be a useful clinical measure. However, these methods should not be used to quantify 3-D joint rotations.

Lower extremity jumping mechanics of female athletes with and without patellofemoral pain before and after exertion

BACKGROUND

Patellofemoral pain is especially common among female athletes and is traditionally associated with lower extremity mechanics thought to increase retropatellar stress. These detrimental mechanics may increase with exertion.

HYPOTHESIS

Differences in lower extremity mechanics during single-legged jumps between female athletes with and without patellofemoral pain will increase after exertion.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty women with patellofemoral pain and 20 healthy female controls participated in a functional lower extremity exertion protocol of repetitive single-legged jumps. Pain, exertion, hip and trunk strength, and 3-dimensional lower extremity joint mechanics were recorded at the beginning and end of the protocol.

RESULTS

The patellofemoral pain group reported increased pain at the conclusion of the protocol. However, all subjects terminated the protocol due to complaints of fatigue. Mean strength measurements for the patellofemoral pain group were 24% lower for lateral trunk flexion (P = .06), 13% lower for hip abduction (P = .09), and 14% lower for hip external rotation (P = .03) than for controls. Subjects with patellofemoral pain demonstrated greater contralateral pelvic drop at the end of the exertion protocol compared with the control group (P = .003). Group differences in lower extremity mechanics, including increased hip adduction angle, hip flexion angle, hip abduction angular impulse, and decreased hip internal rotation angles, were observed among women with patellofemoral pain throughout the exertion protocol. These group differences were consistent despite increased pain for the patellofemoral pain group after exertion. Both groups demonstrated decreased jump height, hip flexion and internal rotation, knee flexion, and hip extension impulse at the end of the protocol.

CONCLUSION

Women with patellofemoral pain demonstrated lower extremity mechanics that differed from the healthy control group during single-legged jumping, particularly at the hip. These differences do not appear to vary with exertion level or pain among patellofemoral pain subjects during single-legged jumps.

CLINICAL RELEVANCE

Lower extremity jumping mechanics appear to be consistently different among women with patellofemoral pain. Conservative treatment programs that include kinematic retraining as well as hip and trunk strengthening may improve patient outcomes and prevent recurrence of this common orthopaedic condition.

Diagnosis and management of a patient with knee pain using the movement system impairment classification system

STUDY DESIGN

Case report.

BACKGROUND

Selecting the most effective conservative treatment for knee pain continues to be a challenge. An understanding of the underlying movement system impairment that is thought to contribute to the knee pain may assist in determining the most effective treatment. Our case report describes the treatment and outcomes of a patient with the proposed movement system impairment (MSI) diagnosis of tibiofemoral rotation.

CASE DESCRIPTION

The patient was a 50-year-old female with a 3-month history of left anteromedial knee pain. Her knee pain was aggravated with sitting, standing, and descending stairs. A standardized clinical examination was performed and the MSI diagnosis of tibiofemoral rotation was determined. The patient consistently reported an increase in pain with activities that produced abnormal motions or alignments of the lower extremity in the frontal and transverse planes. The patient was educated to modify symptom-provoking functional activities by restricting the abnormal motions and alignments of the lower extremity. Exercises were prescribed to address impairments of muscle length, muscle strength, and motor control proposed to contribute to the tibiofemoral rotation. Tape also was applied to the knee in an attempt to restrict tibiofemoral rotation.

OUTCOMES

The patient reported a cessation of pain and an improvement in her functional activities that occurred with correction of her knee alignment and movement pattern. Pain intensity was 2/10 at 1 week. At 10 weeks, pain intensity was 0/10 and the patient reported no limitations in sitting, standing, or descending stairs. The patient's score on the activities of daily living scale increased from 73% at the initial visit to 86% at 10 weeks and 96% at 1 year after therapy was discontinued.

DISCUSSION

This case report presented a patient with knee pain and an MSI diagnosis of tibiofemoral rotation. Diagnosis-specific treatment resulted in a cessation of the patient's pain and an improved ability to perform functional activities.