Holistic approach to understanding anterior knee pain. Clinical implications

Brain network functional connectivity changes in patients with anterior knee pain: a resting-state fMRI exploratory study

BACKGROUND

This study investigates the functional brain connectivity in patients with anterior knee pain (AKP). While biomechanical models are frequently employed to investigate AKP, it is important to recognize that pain can manifest even in the absence of structural abnormalities. Leveraging the capabilities of functional magnetic resonance imaging (fMRI), this research aims to investigate the brain mechanisms present in AKP patients.

METHODS

Forty-five female subjects (24 AKP patients, 21 controls) underwent resting-state fMRI and T1-weighted structural MRI. Functional brain connectivity patterns were analyzed, focusing on pain network areas, and the influence of catastrophizing thoughts was evaluated.

RESULTS

Comparing patients and controls, several findings emerged. First, patients with AKP exhibited increased correlation between the right supplementary motor area and cerebellum I, as well as decreased correlation between the right insula and the left rostral prefrontal cortex and superior frontal gyrus. Second, in AKP patients with catastrophizing thoughts, there was increased correlation of the left lateral parietal cortex with two regions of the right cerebellum (II and VII) and the right pallidum, and decreased correlation between the left medial frontal gyrus and the right thalamus. Furthermore, the correlation between these regions showed promising results for discriminating AKP patients from controls, achieving a cross-validation accuracy of 80.5%.

CONCLUSIONS

Resting-state fMRI revealed correlation differences in AKP patients compared to controls and based on catastrophizing thoughts levels. These findings shed light on neural correlates of chronic pain in AKP, suggesting that functional brain connectivity alterations may be linked to pain experience in this population.

RELEVANCE STATEMENT

Etiopathogenesis of pain in anterior knee pain patients might not be limited to the knee, but also to underlying alterations in the central nervous system: cortical changes might lead a perpetuation of pain.

KEY POINTS

• Anterior knee pain patients exhibit distinct functional brain connectivity compared to controls, and among catastrophizing subgroups. • Resting-state fMRI reveals potential for discriminating anterior knee pain patients with 80.5% accuracy. • Functional brain connectivity differences improve understanding of pain pathogenesis and objective anterior knee pain identification.

Patients with patellofemoral pain have lower soft tissue flexibility of the kinetic chain compared to healthy controls: A case-control study

INTRODUCTION

Patellofemoral pain (PFP) is a common musculoskeletal condition. Lower limb range of motion (LLROM) evaluates soft tissue flexibility over multiple joints as part of the kinetic chain. The aims were to study: 1) the reliability of a new LLROM test; 2) differences in LLROM between PFP patients and controls; and 3) the relationship between LLROM and pain-free knee function.

METHODS

Patients with PFP and matched controls were recruited from a university campus and private physiotherapy clinics, while observers were blinded for health status. Testing LLROM for maximal knee flexion and hip adduction and the sum of these (total ROM) were performed. Measures of reliability (ICC2,1) were established. Univariate linear regression between LLROM and health status and multivariate analysis between LLROM and knee function were performed.

RESULTS

Patients (n = 32 (7 male/25 female, age = 22, BMI = 22.7)) and controls (n = 32 (7 male/25 female, age = 20, BMI = 22.3)) were included. The ICC's for intra- and interobserver reliability ranged from 0.83 (95%CI 0.30-0.93) to 0.89 (0.72-0.95). Symptomatic legs had 7°(3-11, p = 0.014) lower knee flexion, 6°(4-8, p ≤ 0.001) lower hip adduction and 13°(8-17, p ≤ 0.001) lower total ROM than non-symptomatic legs. Multivariate analysis revealed an association between total ROM and pain-free knee function (R2 = 0.438, F = 6.544, p ≤ 0.001).

CONCLUSIONS

The new LLROM test was found to be reliable. Patients with PFP had lower LLROM, which was associated with impaired pain-free knee function. Whether improving soft tissue flexibility results in enhanced pain-free knee function should be the subject of future research.

Patellar Dislocation: Workup and Decision-Making

Acute patellar dislocation (PD) is usually a problem of adolescents and young adults. In most cases, it is a sports-related injury. It is the result of an indirect force on the knee joint, which leads to valgus and external rotation of the tibia relative to the femur. PD is unlikely to occur on a knee with normal patellofemoral joint (PFJ) anatomy. Acute PD consists of an acute injury of the ligamentous medial patellar stabilizers in the background of factors predisposing to patellar instability. These factors are classified into three groups. The first group refers to the integrity of the ligamentous medial patellar restraints, particularly, the medial patellofemoral ligament (MPFL). The second group refers to an abnormal PFJ anatomy, which renders the patella inherently unstable inside the trochlea. The third group refers to the overall axial and torsional profile of the lower limb and to systemic factors, such as ligament laxity and neuromuscular coordination of movement. PD at a younger age is associated with an increased number and severity of patellar instability predisposing factors and lower stress to dislocate the patella. Acute primary PD is usually treated conservatively, while surgical treatment is reserved for recurrent PD. The aim of treatment is to restore the stability and function of the PFJ and to reduce the risk of patellar redislocation. Surgical procedures to treat patellar instability are classified into non-anatomic and anatomic procedures. Non-anatomic procedures are extensor mechanism realignment techniques that aim to center the patella into the trochlear groove. Anatomic procedures aim to restore the PFJ anatomy (ruptured ligaments, osteochondral fractures), which has been severed after the first incident of PD. Anatomic procedures, especially MPFL reconstruction, are more effective in preventing recurrent PD, compared with non-anatomic techniques. Theoretically, all factors that affect PFJ stability should be evaluated and, if possible, addressed. This is practically impossible. Considering that the MPFL ruptures in almost all PDs, MPFL reconstruction is the primary procedure, which is currently selected by most surgeons as a first-line treatment for patients with recurrent PD. Restoration of the axial and torsional alignment of the lower limbs is also increasingly implemented by surgeons. Non-anatomic surgical techniques, such as tibial-tuberosity osteotomy, are used as an adjunct to anatomic procedures. In the presence of multiple PFJ instability factors, acute MPFL reconstruction may be the treatment of choice for acute primary PD as well. Skeletal immaturity of the patient precludes osseous procedures to avoid premature physis closure and subsequent limb deformity. Unfortunately, restoration of the patient's previous activity level or participation in more strenuous sports is questionable and not easy to predict. In the case of competitive athletes, PD may prevent participation in elite levels of sports.

Kinesiophobia Is Associated With Poor Function and Modifiable Through Interventions in People With Patellofemoral Pain: A Systematic Review With Individual Participant Data Correlation Meta-Analysis

OBJECTIVE

The aim of this systematic review and correlation meta-analysis was to identify factors associated with kinesiophobia in individuals with patellofemoral pain (PFP) and to identify interventions that may reduce kinesiophobia in individuals with PFP.

METHODS

Seven databases were searched for articles including clinical factors associated with kinesiophobia or interventions that may reduce kinesiophobia in individuals with PFP. Two reviewers screened articles for inclusion, assessed risk of bias and quality, and extracted data from each study. A mixed-effects model was used to calculate correlations of function and pain with kinesiophobia using individual participant data. Meta-analyses were performed on interventional articles; Grading of Recommendations, Assessment, Development, and Evaluation was used to evaluate certainty of evidence. Results were reported narratively when pooling was not possible.

RESULTS

Forty-one articles involving 2712 individuals were included. Correlation meta-analyses using individual participant data indicated a moderate association between self-reported function and kinesiophobia (n = 499; r = -0.440) and a weak association between pain and kinesiophobia (n = 644; r = 0.162). Low-certainty evidence from 2 articles indicated that passive treatment techniques were more effective than minimal intervention in reducing kinesiophobia (standardized mean difference = 1.11; 95% CI = 0.72 to 1.49). Very low-certainty evidence from 5 articles indicated that interventions to target kinesiophobia (psychobehavioral interventions, education, and self-managed exercise) were better in reducing kinesiophobia than physical therapist treatment approaches not specifically targeting kinesiophobia (standardized mean difference = 1.64; 95% CI = 0.14 to 3.15).

CONCLUSION

Higher levels of kinesiophobia were moderately associated with poorer function and weakly associated with higher pain in individuals with PFP. Taping and bracing may reduce kinesiophobia immediately after use, and specific kinesiophobia-targeted interventions may reduce kinesiophobia following the full intervention; however, the certainty of evidence is very low.

IMPACT

Assessment of kinesiophobia in clinical practice is recommended, on the basis of the relationships identified between kinesiophobia and other important factors that predict outcomes in individuals with PFP.

Should isolated superolateral Hoffa's fat pad edema identified by MRI be reported or ignored in adolescent patients?

BACKGROUND AND OBJECTIVE

The presence of superolateral Hoffa's fat pad (SHFP) edema is associated with several morphometric measurements related to patellar alignment and trochlear morphology. Our aim is to evaluate management implications in adolescent patients with isolated superolateral Hoffa's fat pad edema on MRI.

MATERIALS AND METHODS

Retrospective review of 117 adolescents with knee MRI (mean 14.8 years old) with isolated superolateral Hoffa's fat pad edema. Patients with edema were separated into two groups based on the number of MRI axial slices involved with edema: group 1 (G1) of 27 patients with 1 slice vs group 2 (G2) of 90 patients with 2 or more slices. A comparison control group was used (45 patients who had normal MRI knees). Data points included % referral for physical therapy (PT) or surgery, Hoffa's fat pad edema, tibial tubercle-trochlear groove (TT-TG) distance and lateral trochlear inclination (LTI) angle. Fisher's exact and independent t-tests, ANOVA and regression models were used for statistical analysis.

RESULTS

There is statistically significant difference between Hoffa's fat pad edema patients and control regarding PT referral with G1: 70%, G2: 76%, and control: 53% (p = 0.03). There is statistically significant difference between these groups regarding TT-TG measurements with higher values in edema groups; G1: 11.9 mm±4.1, G2 13 mm ±4.1, and control 8.7 mm±3.6, (p = 0.001). There was a statistically significant association between edema and increased TT-TG distance (p = 0.001) but not LTI angle (p = 0.2).

CONCLUSION

MRI identification of isolated superolateral Hoffa's fat pad edema is positively associated with TT-TG distance and its presence is associated with higher referral rates to physical therapy for patella maltracking.

The influence of iliotibial tract thickness on clinical outcomes in women with patellofemoral pain

BACKGROUND

The assessment of iliotibial tract thickness by ultrasonography may help identify a key, previously unexplored factor that may contribute directly to the homeostasis imbalance of the femoropatellar joint in people with patellofemoral pain (PFP).

OBJECTIVES

To compare the iliotibial tract thickness of people with PFP and asymptomatic people; and to correlate the iliotibial tract thickness with self-reported pain and function of people with PFP.

METHODS

Eighty women, separated into two groups: PFP group (n = 40) and control group consisting of asymptomatic participants (CG; n = 40). The participants answered the Anterior Knee Pain Scale (AKPS) questionnaire, to identify the self-reported knee function; they evaluated the pain in millimeters by the Visual Analog Scale for pain (VAS). For the imaging evaluation, an ultrasound was used, with a linear transducer at the distal portion of the iliotibial tract (coronal plane), with the participants positioned in dorsal decubitus, with 20° of knee flexion. The iliotibial band was visualized in its long axis, and three sequential images were recorded between the lateral femoral condyle and the lateral tibial condyle. The measurements were normalized and correlated.

RESULTS

The groups had no differences (P > 0.001) between participants for: age/weight/height/IMC. Participants in the PFP group had moderate levels of pain (58 + 2.1 mm), considerable self-reported functional limitation (d = 3.05) and greater iliotibial tract thickness compared with the CG (d = 2.41).

CONCLUSION

The iliotibial tract of women diagnosed with PFP have greater thickness compared with asymptomatic women. There was no association between iliotibial tract thickness and subjective measures of pain and function.

Torsional Abnormality: The Forgotten Issue in the Diagnosis and Treatment of the Anterior Knee Pain Patient

Currently, no one doubts that the vast majority of anterior knee pain (AKP) cases do not need surgery [...].

Preoperative muscle thickness influences muscle activation after arthroscopic knee surgery

PURPOSE

The aim of this study was to compare the correlation between preoperative quadriceps femoris muscle thickness and postoperative neuromuscular activation and quadriceps femoris strength in patients with and without patellofemoral pain after arthroscopic partial meniscectomy.

METHODS

A series of 120 patients were prospectively analysed in a longitudinal cohort study of patients scheduled for arthroscopic partial meniscectomy. The patellofemoral pain group included patients who developed anterior knee pain after surgery while the control group included those who had not done so. Patients with preoperative patellofemoral pain, previous knee surgeries as well as those on whom additional surgical procedures had been performed were excluded. Of the 120 initially included in the study, 90 patients were analysed after the exclusions.

RESULTS

There is a direct correlation between preoperative quadriceps femoris muscle thickness and the neuromuscular activity values and the strength of the muscle at 6 weeks after surgery. These results were seen exclusively in the group of patients who do not develop patellofemoral pain (0.543, p = 0.008). The group of patients who developed anterior knee pain in the postoperative period did not show this correlation (n.s.).

CONCLUSION

In patients without patellofemoral pain after meniscectomy, the greater the preoperative thickness of the quadriceps femoris, the more postoperative neuromuscular activation and strength they had. This correlation did not occur in those patients who develop patellofemoral pain after meniscal surgery.

LEVEL OF EVIDENCE

II.

The effects of virtual reality training on clinical indices and brain mapping of women with patellofemoral pain: a randomized clinical trial

Background

Virtual reality training (VRT) is a new method for the rehabilitation of musculoskeletal impairments. However, the clinical and central effects of VRT have not been investigated in patients with patellofemoral pain (PFP). To comprehensively assess the effects of VRT on clinical indices and brain function, we used a randomized clinical trial based on clinical and brain mapping assessment.

Methods

Twenty-six women with PFP for more than 6 months were randomly allocated to 2 groups: intervention and control. The intervention consisted of lifestyle education + 8 weeks VRT, in 24 sessions each lasting 40 min of training, whereas the control group just received lifestyle education. The balance was the primary outcome and was measured by the modified star excursion balance test. Secondary outcomes included pain, function, quality of life, and brain function which were assessed by visual analogue scale, step down test and Kujala questionnaire, SF-36, and EEG, respectively. Pre-intervention, post-intervention and follow-up (1 month after the end of the intervention) measurements were taken for all outcome measures except EEG, which was evaluated only at pre-intervention and post-intervention). Analyses of variance was used to compare the clinical outcomes between the two groups. The independent t-test also was used for between group EEG analyses.

Results

Balance score (P < 0.001), function (P < 0.001), and quality of life (P = 0.001) improved significantly at post-intervention and 1 month follow-up in the VRT group compared with the control group. VRT group showed a significantly decreased pain score (P = 0.004). Alpha (P < 0.05) and theta (P = 0.01) power activity also increased in the brain of the VRT group.

Conclusion

This study demonstrated that long term VRT was capable of improving both clinical impairments and brain function in patients with PFP. Therefore, therapists and clinicians can use this method as a more holistic approach in the rehabilitation of PFP.

Trial registration

IRCT, IRCT20090831002391N40. Registered 23 / 10 / 2019.

Patellofemoral Pain After Arthroscopy: Muscle Atrophy Is Not Everything

Background

It remains unclear as to why patellofemoral pain (PFP) appears in some patients after knee arthroscopy and what influence the quadriceps muscle has on its onset.

Purpose

To compare muscle thickness, neuromuscular contractility, and quadriceps femoris muscle strength between patients who develop PFP after arthroscopic partial meniscectomy and a control group and to compare functional outcomes between these entities.

Study Design

Cohort study; Level of evidence, 3.

Methods

A prospective longitudinal cohort study was carried out on patients scheduled for arthroscopic partial meniscectomy. Patients were excluded if they had preoperative PFP, previous knee surgery, or additional surgical procedures (eg, meniscal repair or microfracture). The following were performed preoperatively: magnetic resonance imaging to quantify muscle thickness, surface electromyography to analyze electrical contractility, and an isokinetic study to assess the strength of the quadriceps femoris muscle. Patients also completed a Lysholm functional questionnaire. Six weeks after the index procedure, patients were questioned about the presence of PFP, and the same tests were repeated. The PFP group included patients who developed anterior knee pain postoperatively, while the control group included those who did not develop pain.

Results

Of 90 initial study patients, 20 were included in the PFP group (23.8%) and 64 in the control group (76.2%); 6 patients were lost to follow-up. Both study groups were comparable on all of the analyzed preoperative variables. Patients in the PFP group had worse results in terms of muscle thickness (9.67 vs 16.55 cm²), electrical contractility (1226.30 vs 1946.11 µV), and quadriceps strength (12.27 vs 20.02 kg; all P < .001). They also presented worse functional results on the Lysholm score (63.05 vs 74.45; P < .001).

Conclusion

Patients who developed PFP after arthroscopic partial meniscectomy had more quadriceps femoris muscle atrophy as well as a greater decrease in electrical contractility and muscle strength at 6 weeks postsurgically as compared with a control group. The PFP group also had worse postoperative functional results.

Reflections on Rotational Osteotomies around the Patellofemoral Joint

Torsional abnormalities of the femur represent a significant risk factor for patellar instability or patellofemoral complaints. Although their clinical implication has been demonstrated, there is still a debate going on about different aspects. These include, especially, the various methods of measurements with a wide range of physiologic values, the indication or clear recommendation for surgical correction, and the site of the rotational osteotomy. Nevertheless, good subjective and objective functional results were reported after femoral rotational osteotomies. This is mostly not a review of the literature, but a collection of personal thoughts and observations.

Short-term effectiveness of an intervention targeting lower limb range of motion on pain and disability in patellofemoral pain patients: A randomized, non-concurrent multiple-baseline study

INTRODUCTION

Patellofemoral pain (PFP) is a common and often long-standing musculoskeletal condition. Evidence of the effectiveness of interventions addressing soft tissue flexibility is conflicting and of inconsistent scientific quality. However, reduced soft tissue flexibility can negatively affect patellofemoral joint kinematics. Lower limb range of motion (LLROM) reflects soft tissue flexibility throughout the kinetic chain. The aim was to evaluate the short-term effectiveness of an intervention targeting LLROM on pain and disability in patients with PFP.

METHODS

A randomized, non-concurrent, multiple-baseline single-case design with a two-week intervention phase and baseline and postintervention phase with varying length was conducted. Eight participants (5 females, 3 males) of age 19(±1.6) years, weekly sports participation 12(±3.1) hours and 17(±14) months symptom duration were included. The Anterior Knee Pain Scale - Dutch Version (AKPS-DV) and the Patient Specific Complaint Scale (PSCS) were administered twice a week. After allocating participants to one of four subgroups of reduced LLROM the intervention was applied. The intervention consisted of soft tissue techniques (mobilization, taping, and stretching).

RESULTS

Participant 3 and 6 showed a medium and small but statistically significant positive effect on the AKPS-DV. Participant 2 showed a large and statistically significant positive effect on the PSCS.

CONCLUSIONS

This study provides moderate evidence that an intervention targeting LLROM in patients with PFP reduces pain and disability in the short-term. Further research is needed to evaluate the long-term effectiveness and optimize individual treatment outcomes.

Development of a Core Set for Knee Dysfunction Based on the International Classification of Functioning, Disability and Health: A Cross-sectional Study

OBJECTIVE

To develop an International Classification of Functioning, Disability and Health core set for patients with knee dysfunction.

DESIGN

Cross-sectional study.

SETTING

The study was conducted at all levels of care (general community, primary care units, rehabilitation clinics/centers, hospital).

PARTICIPANTS

Participants (N=388) with knee dysfunction with or without clinical diagnosis of knee pathology, with or without complaint of pain, with or without instability, and/or with or without knee movement restriction of any type.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Participants were assessed using the core sets for acute and postacute musculoskeletal conditions, the subjective form from the International Knee Documentation Committee scale, the self-report of general health and functionality, and the general health and functionality classified by the researcher. To identify the categories that best explain knee dysfunction, linear regression analyses were performed.

RESULTS

Twenty-four categories were identified from the 75 core set categories for acute and postacute musculoskeletal conditions. Eleven categories belong to the component body functions, 3 represent body structures, 7 represent activities and participation, and 3 represent environmental factors.

CONCLUSIONS

A core set for knee dysfunction that can be used at all levels of health care was proposed, which offers a system for disability assessment related to knee dysfunction, including environmental and social factors. These factors are important for a broad assessment because they include the multiple aspects of functionality, usually not considered in other knee dysfunction assessment instruments. Further analysis of the content and construct validity of the core set is required.

Diagnostic accuracy of ultrasonography in the assessment of anterior knee pain

Background

Anterior knee pain (AKP) is a problematic complaint, considered to be the most frequent cause of orthopedic consultancy for knee problems. This study aimed to highlight diagnostic accuracy of ultrasonography as a fast imaging technique in assessment of patients with AKP.

Methods and results

A prospective study was conducted on 143 patients with clinically confirmed AKP. All patients underwent ultrasonography and MRI examinations of the knee. The diagnostic accuracy of ultrasonography compared to MRI for evaluating different findings of possible causes of AKP were analyzed using receiver operating characteristic (ROC) curve and judged by area under curve (AUC). A total of 155 knees were included in the study; 26 knees showed no abnormalities, 19 knees showed positive MRI only, and 110 knees showed positive ultrasonography and MRI. Ultrasonography and MRI reported 11 different findings of possible causes of AKP or related to it. Joint effusion was the most common finding (38%) followed by trochlear cartilage defect (20.6%) and superficial infrapatellar subcutaneous edema (20%). The overall accuracy of ultrasonography was 85.3% sensitivity and 100% specificity. The ultrasonography provided the highest sensitivity (100%) in detecting bipartite patella, followed by 91.5% for joint effusion, and 87.5% for quadriceps tendinopathy. The ROC curve analysis of overall accuracy of ultrasonography showed an AUC of 0.93. The overall Kappa agreement between ultrasonography and MRI was good (k = 0.66).

Conclusion

Ultrasonography can be used to make a swift screening and assessment of painful anterior knee and as an alternative to MRI when it is unavailable or contraindicated.

Diagnostic accuracy of ultrasonography in the assessment of anterior knee pain

Background

Anterior knee pain (AKP) is a problematic complaint, considered to be the most frequent cause of orthopedic consultancy for knee problems. This study aimed to highlight diagnostic accuracy of ultrasonography as a fast imaging technique in assessment of patients with AKP.

Methods and results

A prospective study was conducted on 143 patients with clinically confirmed AKP. All patients underwent ultrasonography and MRI examinations of the knee. The diagnostic accuracy of ultrasonography compared to MRI for evaluating different findings of possible causes of AKP were analyzed using receiver operating characteristic (ROC) curve and judged by area under curve (AUC). A total of 155 knees were included in the study; 26 knees showed no abnormalities, 19 knees showed positive MRI only, and 110 knees showed positive ultrasonography and MRI. Ultrasonography and MRI reported 11 different findings of possible causes of AKP or related to it. Joint effusion was the most common finding (38%) followed by trochlear cartilage defect (20.6%) and superficial infrapatellar subcutaneous edema (20%). The overall accuracy of ultrasonography was 85.3% sensitivity and 100% specificity. The ultrasonography provided the highest sensitivity (100%) in detecting bipartite patella, followed by 91.5% for joint effusion, and 87.5% for quadriceps tendinopathy. The ROC curve analysis of overall accuracy of ultrasonography showed an AUC of 0.93. The overall Kappa agreement between ultrasonography and MRI was good (k = 0.66).

Conclusion

Ultrasonography can be used to make a swift screening and assessment of painful anterior knee and as an alternative to MRI when it is unavailable or contraindicated.

Combined deepening trochleoplasty and supracondylar external rotation osteotomy for recurrent patellar instability in patients with trochlear dysplasia and increased femoral antetorsion

BACKGROUND

Deepening trochleoplasty has become a part of surgical management in patients with patellar instability and severe trochlear dysplasia. In addition, increased femoral antetorsion is treated most commonly by proximal femoral external rotation osteotomy.

HYPOTHESIS

Deepening trochleoplasty and supracondylar femoral external rotation osteotomy in combination improve patellar stability and function in patients presenting with recurrent patellar instability due to trochlear dysplasia and increased femoral antetorsion.

STUDY DESIGN

Therapeutic case series; Level IV.

METHODS

Combined deepening trochleoplasty and supracondylar external rotation osteotomy were performed in seven female patients (nine knees) with recurrent patellar instability. Trochlear dysplasia (Dejour classification) and increased femoral antetorsion (Murphy computed tomography (CT)-based measurement) were documented using magnetic resonance imaging and CT scans. Data were collected prospectively preoperatively, at 12 months, and at final follow-up. Complete data were available in 100% of cases. Clinical and functional outcomes were evaluated using the Kujala score and Tegner activity level scale.

RESULTS

The average age at the time of surgery was 22.2 years (range, 17-29 years). Preoperative MRI-based findings demonstrated in all patients significant trochlear dysplasia (B in two, C in five, and D in two knees). Femoral antetorsion was 37.8° on average (range, 27-51°). The mean follow-up was 2.1 years after surgery (range, 1-5.5 years). The median Kujala score was 41.2 preoperatively, rising to 83.1 at final follow-up (P = .015). The Tegner activity score improved from a mean preoperative score of 2.7 to a mean postoperative score of 6.0 (P = .020). Good patellar stability without positive apprehension sign was found in all patients. Poor outcome was associated with significant patellofemoral cartilage damage (grade IV) at the time of surgery. A total of 88.8% of patients were satisfied with the knee function at final follow-up. There were no postoperative complications.

CONCLUSION

The combination of deepening trochleoplasty and supracondylar external rotation osteotomy performed in one step is an individually adapted surgical procedure for restoring both horizontal limb alignment and trochlear geometry. It improves patellar stability and yields good subjective and objective functional results in most cases. The condition of the cartilage at the time of surgery is crucial for the outcome with respect to the pain.

Ultrasound-Guided Percutaneous Neuromodulation in Patients with Unilateral Anterior Knee Pain: A Randomized Clinical Trial

The objective of this study was to evaluate the short-term and crossover effects of a percutaneous neuromodulation (PNM) intervention on the femoral nerve, regarding the pain, knee flexion motion (range of motion (ROM)), and functionality, in patients with unilateral anterior knee pain (AKP). Our study used a randomized clinical trial design. Thirty patients were divided into two groups: one asymptomatic knee group in which patients received stimulation in the femoral nerve corresponding to the nonsymptomatic knee; and one symptomatic knee group, in which patients received stimulation in the femoral nerve corresponding to the painful knee. Pain, knee flexion ROM, Victorian Institute of Sport Assessment-Patella (VISA-P) and Kujala questionnaires were evaluated. Twenty-eight patients completed the study. Compared to their baseline values, both groups showed an increase immediately at 24 h, and at 1 week for the knee flexion ROM variable. In addition, the symptomatic knee group showed an increase for the Kujala score and a decrease for the numeric rating scale (NRS) variable from baseline to 1 week. VISA-P score did not show statistically significant differences for the time-group interaction. After the intervention, there were no differences between the groups in any measured time. Conclusion: a single-shot ultrasound-guided PNM intervention per week in the femoral nerve may be an effective treatment for improving the pain, knee flexion ROM, and knee functionality. In addition, this technique produces crossover benefits in the nonintervention limb.

Treatment Success of Hip and Core or Knee Strengthening for Patellofemoral Pain: Development of Clinical Prediction Rules

CONTEXT

  Patellofemoral pain (PFP) is a common injury that interferes with quality of life and physical activity. Clinical subgroups of patients may exist, one of which is caused by proximal muscle dysfunction.

OBJECTIVES

  To develop clinical prediction rules that predict a positive outcome after either a hip and core- or knee-focused strengthening program for individuals with PFP.

DESIGN

  Secondary analysis of data from a randomized control trial.

SETTING

  Four university laboratories.

PATIENTS OR OTHER PARTICIPANTS

  A total of 199 participants with PFP.

INTERVENTION(S)

  Participants were randomly allocated to either a hip and core-focused (n = 111) or knee-focused (n = 88) rehabilitation group for a 6-week program.

MAIN OUTCOME MEASURE(S)

  Demographics, self-reported knee pain (visual analog scale) and function (Anterior Knee Pain Scale), hip strength, abdominal muscle endurance, and hip range of motion were evaluated at baseline. Treatment success was defined as a decrease in visual analog scale score by ≥2 cm or an increase in the Anterior Knee Pain Scale score by ≥8 points or both. Bivariate relationships between the outcome (treatment success) and the predictor variables were explored, followed by a forward stepwise logistic regression to predict a successful outcome.

RESULTS

  Patients with more pain, better function, greater lateral core endurance, and less anterior core endurance were more likely to have a successful outcome after hip and core strengthening (88% sensitivity and 54% specificity). Patients with lower weight, weaker hip internal rotation, stronger hip extension, and greater trunk-extension endurance were more likely to have success after knee strengthening (82% sensitivity and 58% specificity).

CONCLUSION

  The patients with PFP who have more baseline pain and yet maintain a high level of function may experience additional benefit from hip and core strengthening. The clinical prediction rules from this study remain in the developmental phase and should be applied with caution until externally validated.

The current management of patients with patellofemoral pain from the physical therapist's perspective

Patellofemoral pain (PFP) is a common diagnosis that includes an amalgam of conditions that are typically non-traumatic in origin and result in peripatellar and/or retropatellar knee pain. The purpose of this review is to provide an overview of the physical therapist's management, including the evaluation and treatment, of the patient with PFP. A thorough history is critical for appropriately diagnosing and optimally managing PFP; the history should include the date of symptom onset, mechanism of injury and/or antecedent events, location and quality of pain, exacerbating and alleviating symptoms, relevant past medical history, occupational demands, recreational activities, footwear, and patient goals. Physical examination should identify the patient's specific impairments, assessing range of motion (ROM), muscle length, effusion, resisted isometrics, strength, balance and postural control, special tests, movement quality, palpation, function, and patient reported outcome measures. Objective assessments should guide treatment, progression, and clinical decision-making. The rehabilitation program should be individually tailored, addressing the patient's specific impairments and functional limitations and achieving the patient's goals. Exercise therapy, including hip, knee, and core strengthening as well as stretching and aerobic exercise, are central to the successful management of PFP. Other complimentary treatments may include patellofemoral and tibiofemoral joint mobilizations, patellofemoral taping, neuromuscular training, and gait retraining. Appropriate progression of interventions should consider objective evaluations (e.g., effusion, soreness rules), systematic increases in loading, and the chronicity of symptoms. Although short-term changes or reductions in movement often are necessary in a protective capacity, the persistence of altered movement is a key characteristic of chronic pain, which may be managed in part through emphasis on function over symptoms, graded exposure, patient education, and perhaps referral. PFP etiology is largely movement related and a comprehensive conservative treatment using movement can be successful.

Arthroscopic Untethering of the Fat Pad of the Knee: Release or Resection of the Infrapatellar Plica (Ligamentum Mucosum) and Related Structures for Anterior Knee Pain

Anterior knee pain (AKP), a multifactorial symptom complex, can be successfully treated surgically. A specific diagnosis often cannot be made, but the pain is linked to an unrecognized common factor in most patients: the mechanical behavior of the non-isometric contents of the anterior compartment of the knee-the fat pad (FP) and infrapatellar plica (IPP). The objective of this presentation is to describe an effective arthroscopic technique that treats AKP by addressing this common factor. The operation consists of release or resection of the IPP, or ligamentum mucosum, which tethers the FP. These highly innervated tissues act together as a hydraulic shock absorber, filling the anterior compartment. They stretch and deform at the extremes of knee motion because of constraint centrally by the non-isometric IPP. These dynamic changes in shape are eliminated when the plica is released or resected. Pain perception is from perturbed nociceptive nerves: pain relief results from de-tensioning these contained nerves by untethering the fat pad. Ascribing pain causation is problematic because morphologic change, such as inflammation, fibrosis, or contracture of these structures, is only present in a minority of cases. Nonetheless, AKP is both physically linked to these central, pain-sensitive structures and relieved by this operation.

Intra-osseous local anaesthetic patellar pain catheter suppresses osteoarthritic patello-femoral pain

BACKGROUND

The source of pain in patellofemoral osteoarthritis is not fully understood. The purpose of this study was to identify the origin of pain using intraosseous pain catheters and to show early results with an osteotomy that is potentially denervating and hydrostatic pressure-relieving.

METHODS

Five patients with patellofemoral osteoarthritis and pain with straight downward patellofemoral compression were included. All underwent arthroscopic placement of two 0.8mm catheters into the medial and lateral patella prior to subsequent patellar facetectomy with an incomplete horizontal patellar osteotomy. The catheters were first flushed with 0.5ml saline, then with local anaesthetic to determine pain response. After a mean of 44months the latest clinical examination was performed.

RESULTS

Instillation of less than 0.5ml of saline provoked sharp pain, which could be localised by all patients as medial or lateral within the patella. Subsequent instillation of local anaesthetic suppressed the mean patellar tenderness during axial compression from VAS 6 to VAS 1. In one of the five patients, patellar osteotomy did not relieve symptoms and further surgical intervention was required. The remaining four patients experienced a clinical improvement with a mean subjective knee value of 55 (range 40 to 65) out of 100.

CONCLUSION

This is the first report on intraosseous catheters applying local anaesthetics into bone. There is a surprisingly precise intraosseous spatial resolution of pain perception in the patella and triggering of pain in osteoarthritis appears at least in part to occur through intraosseous increase of hydrostatic pressure.

LEVEL OF EVIDENCE

Level IV, Case Series.

Effect of Combined Fibular Osteotomy on the Pressure of the Tibiotalar and Talofibular Joints in Supramalleolar Osteotomy of the Ankle: A Cadaveric Study

We investigated the effect of combined fibular osteotomy on the pressure of the tibiotalar and talofibular joints in medial opening-wedge supramalleolar osteotomy. Three different tibial osteotomy gaps (6, 8, and 10 mm) were created in 10 cadaveric models, and the pressure in the tibiotalar and talofibular joints was measured under axial load before and after fibular osteotomy. The heel alignment angle and talar translation ratio were evaluated radiographically. An increase in osteotomy gap led to increases in hindfoot valgus (p = .001) and the contact and peak pressures in the talofibular joint (p = .03 and p = .004). In contrast, the contact and peak pressures in the tibiotalar joint were unchanged with an increasing osteotomy gap (p = .52 and p = .76). Fibular osteotomy reduced the contact and peak pressures in the talofibular joint (p < .001 and p = .001, respectively), and it did not influence the contact and peak pressures in the tibiotalar joint (p = .46 and p = .14, respectively). Therefore, fibular osteotomy might be necessary in supramalleolar osteotomy for medial ankle arthritis to minimize the increase in pressure in the talofibular joint, especially when the osteotomy gap is large.

How to Deal With Anterior Knee Pain in the Active Young Patient

Context:

Anterior knee pain (AKP) represents the most common reason to consult with a clinician who specializes in the knee. Despite the high incidence of the disorder, however, its etiology is still controversial. Many unnecessary surgeries that may damage the patient are done for this clinical entity.

Evidence Acquisition:

A PubMed search from 1995 through June 2016.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

The etiology of AKP is multifactorial, and patients with AKP may therefore be divided into several subpopulations. The whole picture must be addressed for each patient to identify all potentially modifiable factors and to achieve better outcomes. Both pelvifemoral dysfunction and psychological factors that may affect the development and symptoms of AKP must be considered to identify therapeutic targets within the context of treatment. Patients presenting with AKP frequently respond well to load restriction that protects their knee and reduces pain during rehabilitation. Surgery should only be considered in very select cases. In a patient who has undergone previous patellar realignment surgery and experienced increased pain, iatrogenic medial patellar instability should be considered.

Conclusions:

The etiology of AKP is multifactorial, and several subpopulations of AKP patients exist and their treatment must be personalized. Normally, the focus is on the knee of a patient with AKP, and only that joint is examined. However, that focus can lead to overlooking other important etiological factors that may be present.

A Novel Association between Femoroacetabular Impingement and Anterior Knee Pain

Background. For a long time it has been accepted that the main problem in the anterior knee pain (AKP) patient is in the patella. Currently, literature supports the link between abnormal hip function and AKP. Objective. Our objective is to investigate if Cam femoroacetabular impingement (FAI) resolution is related to the outcome in pain and disability in patients with chronic AKP recalcitrant to conservative treatment associated with Cam FAI. Material and Methods. A retrospective study on 7 patients with chronic AKP associated with FAI type Cam was performed. Knee and hip pain were measured with the visual analogue scale (VAS), knee disability with the Kujala scale, and hip disability with the Nonarthritic Hip Score (NAHS). Results. The VAS knee pain score and VAS hip pain score had a significant improvement postoperatively. At final follow-up, there was significant improvement in all functional scores (Kujala score and NAHS). Conclusion. Our finding supports the link between Cam FAI and AKP in some young patients. Assessment of Cam FAI should be considered as a part of the physical examination of patients with AKP, mainly in cases with pain recalcitrant to conservative treatment.

Patellofemoral pain: Challenging current practice - A case report

Patellofemoral pain (PFP) is a common problem in young people, with 1 in 6 suffering at any one time. It is unclear which management approach is the optimal method for treating PFP in the long term, with traditional physiotherapy examination focusing on assessing for specific structural dysfunction. A rationale for a different assessment and treatment approach, one that moves the focus away from a biomedical/tissue pathology model towards one directed at the neurophysiology of pain, has been suggested. The patient was a 21 year old male with a 6 year history of PFP with previous failed physiotherapeutic treatment. He reported previous multiple healthcare practitioners' advice to avoid activities that were painful as reasons for being unable to participate in sporting activities. No specific structural testing was performed, such as specific muscle strength, length, foot position, patella movement and position, or movement patterns. Descriptions of tissue based pathology models of pain, e.g. patella mal-tracking, were actively discouraged and challenged. The patient was taught to perform one uncomfortable/painful exercise as part of his rehabilitation programme twice a day. The patient achieved 80% improvement in his symptoms over 7 appointments and a return to physical activity following a 5 month rehabilitation programme purposively designed to elicit pain by means of gradually exercising and loading the tissues. This case report highlights the need for further research into exercise protocols for patients suffering with PFP based upon neurophysiology models of pain.

Value of SPECT-CT Imaging for Middle-Aged Patients with Chronic Anterior Knee Pain

Background

Single-photon emission computed tomography-computed tomography (SPECT-CT) is a highly sensitive tool for detecting bone metabolism. We determined whether subchondral bone metabolism, as indicated by SPECT-CT in the patellofemoral (PF) joint, predicts response to conservative management in middle-aged patients with chronic anterior knee pain (AKP), and whether SPECT-CT results correlate with arthroscopic assessments of chondral lesions in the PF joint.

Methods

The study group comprised 74 middle-aged patients with chronic AKP. All of the patients underwent SPECT-CT, and the results were graded along a scale of 0 to 3°. After 8 weeks of conservative management, they were grouped as responders (n = 40) or non-responders (n = 34) according to symptom improvement. We compared the median scintigraphic uptake of the PF joint between the two groups, and evaluated the positive predictive value (PPV) of uptake for treatment response in each patient. In non-responders, cartilage condition was assessed during arthroscopy, and the correlation of scintigraphic uptake with severity of the chondral lesion was assessed.

Results

The median scintigraphic uptake in the patella was higher in non-responders than in responders (2 vs. 1). Among patients with higher patella uptake (grade 2 or 3), the PPV for non-response to conservative therapy was 62–67 %, whereas it was 24–25 % in patients with lower uptake (grade 0 or 1). Patella uptake corresponded strongly with arthroscopic assessment of patellar chondral lesions; the correlation was less strong for the femoral trochlea.

Conclusions

Increased subchondral bone metabolism in the patella is associated with responsiveness to conservative therapy. SPECT-CT can benefit clinicians by predicting the treatment response from conservative management.

Changes in catastrophizing and kinesiophobia are predictive of changes in disability and pain after treatment in patients with anterior knee pain

PURPOSE

The purpose of the study was to investigate if changes in psychological variables are related to the outcome in pain and disability in patients with chronic anterior knee pain.

METHODS

A longitudinal observational study on 47 patients with chronic anterior knee pain was performed in a secondary healthcare setting. Pain was measured with the visual analogue scale and disability with the Lysholm scale. The psychological variables, such as anxiety, depression, pain coping strategies, catastrophizing and fear to movement beliefs, were studied by using self-administered questionnaires.

RESULTS

Among the pain coping strategies, only the catastrophizing subscale showed a significant reduction. Similarly, anxiety, depression and kinesiophobia were significantly reduced after treatment. Those patients who decreased the catastrophizing, kinesiophobia, anxiety and depression showed a greater improvement in pain and disability after a purely biomedical treatment. A multiple regression analysis revealed that changes in catastrophizing predicted the amount of improvement in pain severity and that changes in both catastrophizing and anxiety predicted changes in disability after treatment.

CONCLUSION

What has been found suggests that clinical improvement in pain and disability is associated with a reduction in catastrophizing and kinesiophobia. Therefore, co-interventions to reduce catastrophizing thinking and kinesiophobia may enhance the results.

LEVEL OF EVIDENCE

Prospective Cohort Study, Level I for prognosis.