Current clinical, radiological and treatment perspectives of patellofemoral pain syndrome

Treatment of anterior knee pain due to chondromalacia patellae with platelet-rich plasma and hyaluronic acid in young and middle-aged adults, a cohort study

INTRODUCTION

Anterior knee pain commonly affects young women resulting in the declination of the quality of life. One of the possible pathologies causing this symptom is chondromalacia patellae (CMP). Although CMP is used to describe the softening of patellar articular cartilage, it remains a general descriptive term as it cannot be associated with a specific pathophysiologic mechanism. The objective of this study is to investigate the effect of injectable PRP on patients with anterior knee pain in absence of altered patellofemoral joint anatomy.

METHODS

For this purpose, 43 patients of the affected population were recruited to participate in this non-randomized controlled trial, 28 patients in the injection group and 15 in the only-physiotherapy group. While patients in the experimental group received three PRP injections and one injection of hyaluronic acid (HA), comparators received the standard physical therapy regimen. The treatment choice was based on patients own decree. Patients between the ages of 18 to 50 years with anterior knee pain and positive Clarke´s sign were eligible for inclusion. Patients with evident anatomical abnormalities, chronic conditions affecting the knee and severe symptoms such as blocking, were excluded from the study. Patient related measures (PROMS) in the form of the VAS and the Kujala scores were the main outcome of interest. All outcomes were measured at baseline, and after 3 and 6 months after the treatment.

RESULTS

Although an improvement was seen in both groups, a statistically significant difference favoring the injection of PRP over the physiotherapy-only group was observed (p < 0.001). The superiority of the therapeutic modality under investigation was observed at 3 and 6 months after the initial diagnosis was made. Furthermore, the results of this study revealed a significant improvement at 3 and 6 months when compared to baseline measures. The analysis of the patients age showed a negative correlation when baseline values were compared to measures at 3 and 6 months, meaning younger patients had more benefit from the treatment.

DISCUSSION

The main results of this study affirm the positive effects of PRP and HA for the treatment of anterior knee pain described by previous research and the subsequent improvement of the quality of life. Relatively little information was found in the literature search regarding the therapeutic effects of PRP on anterior knee pain and chondropathies. While a previous radiologic study found no evidence regarding the effect of PRP, this study found a benefit when comparing PROMs between patient groups.

Patello-Femoral Pain Syndrome: Magnetic Resonance Imaging versus Ultrasound

BACKGROUND

Magnetic Resonance Imaging (MRI) and Ultrasound (US) in combination with clinical data could contribute to the diagnosis, staging and follow-up of Patello-Femoral Syndrome (PFS), which often overlaps with other pathologies of the knee.

PURPOSE OF THE STUDY

To evaluate the diagnostic role of MRI and US findings associated with PFS and define the range values of instrumental measurements obtained in pathological cases and healthy controls, the performance of the two methods in comparison, and the correlation with clinical data.

MATERIALS AND METHODS

100 subjects were examined: 60 patients with a high suspicion of PFS at the clinical evaluation and 40 healthy controls. All measurements obtained by MRI and US examination were correlated with clinical data. A descriptive analysis of all measurements was stratified for pathological cases and healthy controls. A Student's t-test for continuous variables was used to compare patients to controls and US to MRI. Logistic regression analysis was applied to test the correlation between MRI and US measurements with clinical data.

RESULTS

Statistical descriptive analysis determined the MRI and US range values of medial patello-femoral distance and the thickness of retinacles and cartilages in pathological cases and healthy controls. In pathological cases, the retinacle results of both increased; the medial appeared to be slightly more increased than the lateral. Furthermore, in some cases, the thickness of the cartilage decreased in both techniques; the medial cartilage was more thinned than the lateral. According to logistic regression analyses, the best diagnostic parameter was the medial patello-femoral distance due to the overlapping results of the US and MRI. Furthermore, all clinical data obtained by different tests showed a good correlation with patello-femoral distance. In particular, the correlation between medial patello-femoral distance and the VAS score is direct and equal to 97-99%, which is statistically significant (p < 0.001), and the correlation with the KOOS score is inverse and equal to 96-98%, which is statistically significant.

CONCLUSIONS

MRI and Ultrasound examination in combination with clinical data demonstrated high-value results in the diagnosis of PFS.

Effect of Adding Kinesio Taping to Exercise Therapy in the Treatment of Patellofemoral Pain Syndrome

Background and objectives: Patellar taping has been widely used for the primary or adjunctive treatment of patellofemoral pain syndrome (PFPS); however, there are limited data in terms of functional outcomes. This study aimed to investigate whether there is any beneficial effect of adding Kinesio Taping^® (KT) to exercise therapy in the treatment of PFPS. Materials and Methods: Twenty patients (27.5 ± 5.4 years) with PFPS who applied KT and 19 patients (27.3 ± 7.4 years) who did not were included in this study. Quadriceps muscle strength and acceleration time (AT) were assessed using an isokinetic device. Patient-reported outcomes were evaluated using the Kujala anterior knee pain scale (AKPS). Both groups underwent one-month exercise therapy. Results: There was no significant difference in quadriceps strength, AT, and AKPS at baseline and at 1 month between the taping and non-taping groups (p > 0.05). However, for quadriceps muscle strength, the effect of time*group interaction was statistically significant (F(1.37) = 4.543, p < 0.05, partial eta squared 0.109), showing that improvement in the quadriceps strength was higher in the non-taping group than that in the taping group. Conclusions: Adding KT to exercise therapy did not elicit extra benefits in quadriceps muscle strength and AT, and AKPS among PFPS with abnormal patellar tracking at one month.

Patellofemoral Syndrome: a Review of Diagnosis and Treatment

Purpose of Review

Patellofemoral syndrome (PFS) is a common condition seen in people with anterior knee pain. This review explores patient presentations and exam maneuvers used for diagnosis, as well as established/up-and-coming treatment interventions.

Recent Findings

Pain reduction and prevention are the main goals for PFS as they negatively affect quality of life. Combination hip and knee exercises have been found to be most beneficial during therapy due to the multifactorial etiology of PFS. Combining exercise therapy with patellar taping has also shown a reduction in acute pain. Ultrasound may be used to evaluate for associated findings. Blood flow restriction and trigger point injections are options that may be helpful for pain reduction but further research is required.

Summary

PFS is a common clinical diagnosis requiring a robust patient history, supported by various physical exam maneuvers. Treatment involves a patient tailored approach, often with combinations of conservative management and interventional procedures.

Imaging evaluation of patellofemoral joint instability: a review

The multifactorial origin of anterior knee pain in patellofemoral joint disorders leads to a demanding diagnostic process. Patellofemoral misalignment is pointed out as one of the main causes of anterior knee pain. The main anatomical risk factors of patellofemoral instability addressed in the literature are trochlear dysplasia, abnormal patellar height, and excessive tibial tubercle-trochlear groove distance. Diagnostic imaging of the patellofemoral joint has a fundamental role in assessing these predisposing factors of instability. Extensive work is found in the literature regarding the assessment of patellofemoral instability, encompassing several metrics to quantify its severity. Nevertheless, this process is not well established and standardized, resulting in some variability and inconsistencies. The significant amount of scattered information regarding the patellofemoral indices to assess the instability has led to this issue. This review was conducted to collect all this information and describe the main insights of each patellofemoral index presented in the literature. Five distinct categories were created to organize the patellofemoral instability indices: trochlear dysplasia, patellar height, patellar lateralization, patellar tilt, and tibial tubercle lateralization.

Improvement of Pain and Function by Using Botulinum Toxin Type A Injection in Patients with an Osteoarthritic Knee with Patellar Malalignment: An Electromyographic Study

Objective: To determine the pain and electromyographic (EMG) amplitude ratio of the vastus medialis oblique (VMO) to the vastus lateralis (VL) after botulinum toxin type A (BTA) was injected in the bilateral osteoarthritic knee of patients with patellar malalignment for analysis. Material and methods: A total of fifteen patients were recruited; the more symptomatic knee of each patient received a BTA injection (BTA side). The other set of patients were left untreated. In all, fifteen healthy participants comprised the control group. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and numeric rating scale (NRS) for pain were assessed. The EMG amplitude of VL and VMO activity was recorded using an isokinetic dynamometer and synchronized using the BIOPAC MP100. The data were collected before and at 4, 8, and 12 weeks post−BTA injection. Results: The EMG ratios of the patient group were lower than those of the control group at all testing velocities (p < 0.05). The VMO/VL ratio improved significantly on the BTA side only. The VMO/VL ratios on the BTA side were higher than those on the untreated side (p < 0.05). Knee pain decreased significantly after the BTA injection. The EMG ratios were negatively correlated with the NRS and WOMAC scores. Conclusion: BTA injection effectively reduces knee pain and restores the EMG ratio between the VMO and VL.

Automatic measurement of the patellofemoral joint parameters in the Laurin view: a deep learning-based approach

OBJECTIVES

To explore the performance of a deep learning-based algorithm for automatic patellofemoral joint (PFJ) parameter measurements from the Laurin view.

METHODS

A total of 1431 consecutive Laurin views of the PFJ were retrospectively collected and divided into two parts: (1) the model development dataset (dataset 1, n = 1230) and (2) the hold-out test set (dataset 2, n = 201). Dataset 1 was used to develop the U-shaped fully convolutional network (U-Net) model to segment the landmarks of the PFJ. Based on the predicted landmarks, the PFJ parameters were calculated, including the sulcus angle (SA), congruence angle (CA), patellofemoral ratio (PFR), and lateral patellar tilt (LPT). Dataset 2 was used to assess the model performance. The mean of three radiologists who independently measured the PFJ parameters was defined as the reference standard. Model performance was assessed by the intraclass correlation coefficient (ICC), mean absolute difference (MAD), and root mean square (RMS) compared to the reference standard. Ninety-five percent limits of agreement (95% LoA) were calculated pairwise for each radiologist, reference standard, and model.

RESULTS

Compared with the reference standard, U-Net showed good performance for predicting SA, CA, PFR, and LPT, with ICC = 0.85-0.97, MAD = 0.06-5.09, and RMS = 0.09-6.90 in the hold-out test set. Except for the PFR, the remaining parameters measured between the reference standard and the model were within the 95% LoA in the hold-out test dataset.

CONCLUSIONS

The U-Net-based deep learning approach had a relatively high model performance in automatically measuring SA, CA, PFR, and LPT.

KEY POINTS

• The U-Net model could be used to segment the landmarks of the PFJ and calculate the SA, CA, PFR, and LPT, which could be used to evaluate the patellar instability. • In the hold-out test, the automatic measurement model yielded comparable performance with reference standard. • The automatic measurement model could still accurately predict SA, CA, PFR, and LPT in patients with PI and/or PFOA.

Patellofemoral Pain Syndrome in Young Female Athletes: A Case-Control Study

Background

Patellofemoral pain syndrome (PFPS) is the most common cause of anterior knee pain in children and adolescents, and it is characterized by highly limiting, recurrent, frontal pain.

Objectives

The purpose of the study is to assess the incidence and onset of PFPS in the young female athletes and to compare it to healthy individuals.

Methods

Between 2017 and 2019, 51 subjects were reviewed and divided in three groups: rhythmic gymnastics athletes (RG; 21 individuals, mean age: 13.8 ± 3.6 years), basketball athletes (BG; 17 individuals, mean age: 14.2 ± 3.1 years), and control group (CG; 13 individuals, mean age: 14.5 ± 4.3 years). All patients underwent physical examination including patellar glide, tilt, grind and apprehension tests, tiptoe and jack tests, Coleman block, and navicular drop tests. The clinical and functional outcomes of the subjects were assessed using the Kujala patellofemoral score (KPS).

Results

In RG patients were recorded 66.7% of normal footprint (NF), 9.5% of cavus feet (FCF), and 23.8% of flatfeet (FFF); 14.8% patellar positive tests, KS = 98.6 ± 13.7. BG patients had 70.6% of NF, 11.8% FCF, and 17.6% of FFF; 23.5% patellar positive tests, KS = 98.3 ± 12.4. CG patients had 61.5% of NF, 7.7% of FCF and 30.8% of FFF; 15.4% patellar positive tests, KPS = 98,9 ± 15.3. No statistically significance was found between the three cohorts of patients.

Conclusions

PFPS is a common pathology; muscular imbalance and overuse could exacerbate pain and discomfort in young female athletes. Our findings show high type and level of sport activity are not related to increase frequency of clinical symptoms related to PFPS.

Usefulness of three-dimensional computed tomography for patellofemoral measurement

PURPOSE

This study aimed to establish the normal values for knee patellofemoral alignment as measured using 3-dimensional computed tomography (3D CT), to standardize the technique, and to show the inter- and intra-observer reliability of this measurement.

METHODS

The present study included 62 asymptomatic volunteers (124 knees). 3D CT scanning was performed with each volunteer in the supine position with 15° of knee flexion, and consistent 3D axial images of the patellofemoral joint were obtained with alignment in the desired stereographic baseline direction in anterior-posterior, lateral, and axial rotations. Two independent observers measured patellofemoral alignment parameters, including the sulcus angle, congruence angle, lateral patellofemoral angle, condyle-patellar angle, and lateral trochlear inclination angle.

RESULTS

Based on 3D CT measurement, the mean values of the parameters were 145.9° ± 9.2° for the sulcus angle, 12.6° ± 22.6° for the congruence angle, 9.2° ± 4.6° for the lateral patellofemoral angle, 14.1° ± 6.4° for the condyle-patellar (lateral facets) angle, - 8.5° ± 8.4° for condyle-patellar (patellar axis) angle, and 16.5° ± 6.3° for the lateral trochlear inclination angle. A statistically significant difference was observed between men and women in the sulcus and condyle-patellar (patellar axis) angles (p = 0.045, 0.011, respectively). All parameters showed excellent inter- and intra-observer reliability.

CONCLUSION

The normal values and ranges for patellofemoral alignment parameters were evaluated using 3D CT. The results of this study provide reference information that may facilitate diagnosis and treatment planning of patellofemoral disorders in skeletally mature non-pathologic patients.

LEVEL OF EVIDENCE

II.

Botulinum toxin injections as salvage therapy is beneficial for management of patellofemoral pain syndrome

Purpose

Patellofemoral pain syndrome (PFPS) is a common pathology usually presenting with anterior or retropatellar pain. It is associated with a relative imbalance between the vastus medialis oblique (VMO) and the vastus lateralis (VL) muscles. This can lead to considerable morbidity and reduced quality of life (QOL). This study aims to assess the long-term functional outcome of PFPS treated with VL muscle botulinum toxin A (BoNT-A) injection.

Materials and methods

A retrospective review was performed on 26 consecutive patients (31 knees) with a mean age of 50.1 years (± 19.7 years) who were treated with BoNT-A injections to the VL muscle followed by physiotherapy between 2008 and 2015. Pre- and post-treatment pain levels (numerical rating scale, NRS), QOL (SF-6D), and functional scores (Kujala and Lysholm questionnaires) were measured. Demographics, physical therapy compliance, previous surgeries, perioperative complications, and patient satisfaction levels were collected.

Results

The mean follow-up time was 58.8 ± 36.4 months. There were significant improvements in all the examined domains. The average pain score (NRS) decreased from 7.6 to 3.2 (P < 0.01), and the Kujala, Lysholm, and SF-6D scores improved from 58.9 to 82.7 (P < 0.001), 56.2 to 83.2 (P < 0.001), and 0.6 to 0.8 (P < 0.001), respectively. Similar delta improvement was achieved irrespective of gender, age, compliance to post-treatment physical therapy, or coexisting osteoarthritis. Patients who presented with a worse pre-treatment clinical status achieved greater improvement. Prior to BoNT-A intervention, 16 patients (18 knees) were scheduled for surgery, of whom 12 (75%, 13 knees) did not require further surgical intervention at the last follow-up.

Conclusions

A single intervention of BoNT-A injections to the VL muscle combined with physiotherapy is beneficial for the treatment of patients with persistent PFPS.

Level III evidence

Retrospective cohort study.

Patellofemoral kinematics in patellofemoral pain syndrome: The influence of demographic factors

Due to the multifactorial nature of patellofemoral pain, it is often difficult to identify an individual patient's exact cause of pain. Understanding how demographic variability influences these various factors will support improved consensus in regards to the etiology of PF pain. Thus, in this retrospective study, we tested the hypothesis that sex, height, weight, body mass index (BMI), and age influence the determination of between-groups differences in PF kinematics. We included 41 skeletally mature patients with patellofemoral pain and 79 healthy controls. Three-dimensional patellofemoral kinematics were quantified from dynamic magnet resonance images. We ran multiple regression analyses to determine the influence of demographic covariates (age, sex, height, weight, and BMI) on patellofemoral kinematics. Patellar shift was significantly influenced by weight (p = 0.009) and BMI (p = 0.009). Patellar flexion was influenced by height (p = 0.020) and weight (p = 0.040). Patellar tilt and superior displacement were not influence by demographic variables. Age and sex did not influence kinematics. This study supports the hypothesis that demographic parameters influence PF kinematics. The fact that weight, a modifiable measure, influences both patellar shift and flexion has strong implications for future research and clinical interventions. Clinically, weight loss may have a dual benefit of reducing joint stress and maltracking in patients who are overweight and experiencing patellofemoral pain. The influence of key demographics on patellofemoral kinematics, reinforces the clear need to control for population characteristics in future studies. As such, going forward, improved demographic matching between control and patient cohorts or more advanced statistical techniques that compensate for confounding variables are necessary.

Patella dislocation: an overview

Patella dislocation is one of the most common knee injuries, accounting for 3% of acute knee injuries. Despite its prevalence, patella dislocation is often missed, with a haemarthrosis often the only sign, albeit a non-specific one. A thorough history and examination are necessary to identify patella dislocation and its potential causes. Investigations should include cross-sectional imaging to evaluate both osseous and soft tissue structures in order to guide management. Management in the acute setting is normally non-operative, but damage to structural supports, osteochondral defects or recurrent dislocation should prompt consideration of operative treatment. Operative treatment should address the soft tissue stabilisers and/or osseus deformities that predispose to, or occur secondary to, patella dislocation.

Imaging of Pediatric Lower Limb Sports Injuries

The importance of physical activity during childhood and adolescence has come to light, with an increase in sports-related acute traumatic and overuse injuries as a major disadvantage. A solid understanding of the physiology of the growing skeleton, together with knowledge about age- and sex-related differences in the occurrence of acute traumatic and overuse injuries is necessary. Every musculoskeletal radiologist should also be familiar with the appearances of these injuries on different imaging modalities. This review focuses on all these aspects concerning acute traumatic and overuse injuries among children and adolescents.

Static and Dynamic Quadriceps Stretching Exercises in Patients With Patellofemoral Pain: A Randomized Controlled Trial

BACKGROUND

Limited data are available on the effect of stretching exercise in patients with patellofemoral pain (PFP) who have inflexible quadriceps, which is one of the various causes of PFP syndrome. This study compares quadriceps flexibility, strength, muscle activation time, and patient-reported outcomes after static and dynamic quadriceps stretching exercises in patients with PFP who had inflexible quadriceps.

HYPOTHESIS

Quadriceps flexibility and strength, muscle activation time, and patient-reported outcomes would improve with dynamic quadriceps stretching as compared with static quadriceps stretching exercises.

STUDY DESIGN

Randomized controlled trial.

LEVEL OF EVIDENCE

Level 2.

METHODS

Of the 44 patients included in the study, 20 performed static stretching and 24 performed dynamic stretching. Quadriceps flexibility was assessed by measuring the knee flexion angle during knee flexion in the prone position (the Ely test). Muscle strength and muscle activation time were measured using an isokinetic device. The patient-reported outcomes were evaluated using the visual analogue scale for pain and anterior knee pain scale.

RESULTS

No significant differences in quadriceps flexibility and strength, muscle activation time, and patient-reported outcomes in the involved knees were found between the 2 groups (P values > 0.05).

CONCLUSION

Quadriceps flexibility and strength, muscle activation time, and patient-reported outcomes in patients with PFP who had inflexible quadriceps showed no significant differences between the static and dynamic quadriceps stretching exercise groups.

CLINICAL RELEVANCE

Both static and dynamic stretching exercises may be effective for improving pain and function in patients with PFP who have inflexible quadriceps.

Patella-patellar tendon angle decreases in patients with infrapatellar fat pad syndrome and medial patellar plica syndrome

PURPOSE

Infrapatellar fat pad (IPFP) syndrome and medial patellar plica (MPP) syndrome are two recognized causes of anterior knee pain. However, diagnosing these syndromes is challenging without arthroscopic examination. The aim of this study was to evaluate sagittal patellar tilt in patients with IPFP syndrome or MPP syndrome by measuring the patella-patellar tendon angle (PPTA) in affected patients.

METHODS

Eighty-three patients with anterior knee pain who underwent diagnostic arthroscopy that confirmed isolated IPFP or MPP syndrome from 2011 to 2016 were included in this retrospective study. Patients were divided into Group A (IPFP syndrome, n = 44) and Group B (MPP syndrome, n = 39). The control group included 78 patients without knee pathology who underwent magnetic resonance imaging (MRI) of the knee during the study period. Radiographic measurements, including PPTA, IPFP area, patellar height, axial patellar alignment, patellar tilt, sulcus angle, and lateral trochlear inclination, were made on MRI images by two experienced sports medicine orthopedists.

RESULTS

The mean PPTA in each knee-pathology group was significantly smaller than that in the control group (Group A: 137.3° ± 4.9°; Group B: 138.1° ± 3.2°; control group, 141.4° ± 2.9°). There was no significant difference between groups for any other radiographic parameter evaluated.

CONCLUSION

The PPTA was significantly smaller in patients with IPFP syndrome or MPP syndrome than in healthy controls. Therefore, sagittal patellar tilt should be included in the routine evaluation of patients with anterior knee pain. Evaluation of PPTA may help to diagnose IPFP syndrome or MPP syndrome.

LEVEL OF EVIDENCE

Level IV.

Assessment and Management of Somatic Dysfunctions in Patients With Patellofemoral Pain Syndrome

Context

Patellofemoral pain syndrome (PFPS) is one of the most common determinants of knee pain. The causes of PFPS are multifactorial, and most treatment approaches are conservative. There are many kinds of therapy for this syndrome, which are based on building strength, flexibility, proprioception, and endurance. Training is functional and progression is gradual. Our hypothesis is that total-body osteopathic manipulative therapy (OMTh; manipulative care provided by foreign-trained osteopaths) focused on the management of somatic dysfunctions could be useful for managing the pain of patients with PFPS.

Objective

To investigate the effect of OMTh on pain reduction in patients with PFPS.

Methods

This pilot study was randomized, controlled, and single-blinded with 2 months of follow-up. Qualified participants were randomly assigned to 1 of 2 groups: OMTh group or placebo group. Each participant received either 4 sessions of OMTh or 4 sessions of manual placebo intervention that consisted of passive touching without joint mobilization in a protocolled order. A visual analogue scale (VAS) was used to assess general knee pain, peripatellar pain, pain after prolonged sitting, pain during the patellar compression test, and pain during stair ascent and descent. Pain assessment was performed before the baseline (T0), second (T1), third (T2), and fourth (T3) sessions, and follow-up (T4) was performed 8 weeks after T3.

Results

Thirty-five participants were enrolled the study. The VAS score was significantly reduced and clinically relevant in the OMTh group after each treatment and after 2 months of follow-up. The change in the VAS score before each treatment indicates that the most improved areas at T1 compared with T0 were lumbar and sacral with improvements in 83% and 40% of patients, respectively. At T2 compared with T1, the most improved areas were cervical and sacral with improvements found in 58% and 36% of patients, respectively. The number of dysfunctions that were diagnosed decreased during the baseline to T3 period (40% change). The correlation analysis showed significant results for the dysfunction and the compression test at T2 (P=.01, ρ=0.543).

Conclusion

Significant differences in VAS scores were found between the OMTh and placebo groups. These findings underline how OMTh can lead to reduced pain in patients with PFPS.