Patellofemoral malalignment

Is the effectiveness of patellofemoral bracing modified by patellofemoral alignment and trochlear morphology?

Background

This study was performed to determine if the effectiveness of patellofemoral bracing as a treatment for patellofemoral osteoarthritis is influenced by patellofemoral joint alignment and trochlear morphology. We hypothesized that those with more extreme patellar malalignment would benefit more from bracing.

Methods

Thirty-eight patients who had received bracing as part of a comprehensive treatment plan for patellofemoral osteoarthritis were selected for this study. Ten measures of patellar alignment were taken from X-rays. These alignment measures were divided into percentile groups (tertiles) for contingency table analysis. Treatment outcome was measured by Western Ontario and Macmasters Universities Osteoarthritis Index (WOMAC) scores and these were dichotomised into two groups according to “Improved” or “Not Improved” according to the minimum clinically important difference (MCID). Spearman’s rho test was performed for continuous variables and Fisher’s exact test was performed for correlation between tertile groups and MCID categories.

Results

Thirty-eight patients (9 male and 29 female) between the ages of 51 to 89 were included in this study. WOMAC scores ranged from −25 to 41.67, with a mean change of −3.97, 31.6, 44.7 and 31.6% of patients falling into the “Improved” group for Global, Pain and Function scores respectively. We found a non-significant trend shown (p = 0.058, correlation coefficient 0.31) between bisect offset and change in WOMAC global, indicating a trend for higher change in WOMAC scores with increasing bisect offset. Statistically significant correlations were found between mean MCID categories for the WOMAC global and function groups when analysed against percentile groups for bisect offset (p < 0.01) and patellar subluxation distance (p < 0.05), indicating those in higher percentile groups were more likely not to improve after six months.

Conclusion

Higher bisect offset and patellar subluxation distance measures were associated with poorer outcomes. However, due to the limited sample size, more studies are required to fully examine this relationship.

Comparison of symptoms and clinical findings in subgroups of individuals with patellofemoral pain

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.

Diffusely increased bone scintigraphic uptake in patellofemoral pain syndrome

OBJECTIVES

Painful disorders of the patellofemoral joint are one of the most frequent complaints in orthopaedic and sports medicine. The aims of this study were to determine whether bone scintigrams of patients suffering from patellofemoral pain syndrome (PFPS) show diffuse uptake and in what bony compartment of the knee uptake, if any, was localised.

METHODS

Fifty eight patients with chronic PFPS were examined. All patients underwent a detailed clinical history and a thorough physical examination of the knee. Anterior and lateral static images of both knees were made using a gamma camera 3 h after injection of 550 MBq of (99m)Tc-HMDP. Two experienced radiologists visually evaluated the scans blindly and separately. As 51 patients had bilateral pain, 109 painful knees are included in the results.

RESULTS

Diffuse uptake on bone scintigrams was found in 48 knees in 30 of the patients. In 33 knees the uptake was localised to only one bone compartment, in 10 knees diffuse uptake was found in two of the bones forming the knee joint, and in six knees all three bone compartments (the distal femur, the patella, and the proximal tibia) exhibited diffuse uptake.

CONCLUSIONS

Scintigrams of approximately half of the patients with PFPS will show diffuse uptake in one or more of the bony compartments of the knee joint and radioactive tracer accumulation will occur as often in the proximal tibia as in the patella.

Bilateral Q angle asymmetry and anterior knee pain syndrome

OBJECTIVE

To determine whether quadriceps (Q) angles were bilaterally symmetric in individuals asymptomatic vs symptomatic for anterior knee pain.

DESIGN

Cross-sectional study.

BACKGROUND

Previous attempts to link excessive Q angles to the occurrence of knee pain have yielded equivocal results. Deriving unilateral rather than bilateral measures of the Q angle and thereafter analysing data using traditional between-group analysis-of-variance structural models may, however, play a role in obscuring the true nature of the Q angle-knee pain relationship.

METHODS

Left and right Q angles were goniometrically measured in 75 subjects (37 males, 38 females) while they adopted a static, standing position with quadriceps relaxed. The majority (n = 50) were asymptomatic, while the remainder were unilaterally (n = 11) or bilaterally (n = 14) symptomatic for anterior knee pain. A questionnaire was used to determine the extent and magnitude of pain experienced in each of the symptomatic subjects.

RESULTS

Significant right vs left lower limb differences in Q angles were observed by group (p < 0.001) and group by gender (p < 0.05). Mean values, however, did not always reflect the true variation of data within the sample. Forty-seven percent of the subjects studied demonstrated a minimum 4 degrees bilateral Q angle difference, while in 13 of 75 subjects, this difference ranged from 8 degrees to 12 degrees. Only a weak yet significant relationship between right and left Q angles (r = 0.53, p < 0.001) was noted. While there were no correlations between Q angle measures and the magnitude of discomfort experienced in unilateral knee pain sufferers, these relationships were weak yet significant in bilateral knee pain sufferers.

CONCLUSION

Q angles are not bilaterally symmetric, with the magnitude and direction of the observed asymmetry varying according to whether an individual is asymptomatic, unilaterally symptomatic, or bilaterally symptomatic for anterior knee pain.

RELEVANCE

Future investigations of the Q angle must ensure that measures are derived bilaterally and analysed appropriately. Data from unilateral vs bilateral symptomatic subjects should be evaluated separately, and the shortcomings of standard ANOVA structural models must be recognized.

The quadriceps angle: a review of the literature

Previous investigations of the quadriceps (Q) angle and its relationship to knee disorders have yielded equivocal results. The purpose of this paper is to present a review of the current literature on the Q angle and to examine the differences in Q angles when measured: 1) under differing measurement protocols; 2) between asymptomatic and symptomatic populations; 3) between male and female samples; and 4) from side to side within subjects. Little scientific evidence exists to support the commonly held assumptions that Q angles are larger in symptomatic vs. asymptomatic or that they are equal in the right vs. left lower limb. However, larger mean values are consistently observed in groups of young adult females vs. young adult males.