Patellofemoral stress. A prospective analysis of exercise treatment in adolescents and adults

Comprehensive Analysis of Minimally Invasive Management for Persistent Anterolateral Ankle Pain: A Systematic Review

Persistent anterolateral ankle pain is a debilitating condition often associated with soft tissue impingement following inversion injuries. It can lead to significant limitations in daily activities and overall quality of life, particularly in individuals with chronic ankle instability. This systematic review examines the efficacy and safety of minimally invasive arthroscopic decompression techniques in managing anterolateral ankle impingement syndrome. A total of 246 cases from nine studies were reviewed, involving 135 males with a mean age of 29.6 years and an average follow-up period of 29.5 months (range: 15-83.7 months). Outcomes were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) scores and Meislen criteria. The AOFAS scores improved significantly from a mean of 40.75 preoperatively to 84.2 postoperatively, reflecting substantial functional recovery. Based on the Meislen criteria, 124 cases (50%) were rated as excellent, 71 (29%) as good, 14 (6%) as fair, and three (1%) as poor. Postoperative mobility was restored to normal in 130 cases, with complications reported in 24 cases (9.8%), including hypoesthesia, infections, intra-articular haemarthrosis, scar tissue formation, nerve irritation, and persistent pain or numbness. Patient satisfaction was high, with most patients reporting significant improvements in pain relief and functional capacity. Arthroscopic decompression is a safe, minimally invasive, and effective intervention for managing persistent anterolateral ankle impingement, offering substantial improvements in pain, mobility, and overall function with low morbidity and a manageable complication rate. This approach is an invaluable option for patients unresponsive to conservative treatments.

Adolescents and adults with patellofemoral pain exhibit distinct patellar maltracking patterns

BACKGROUND

Chronic idiopathic patellofemoral pain is associated with patellar maltracking in both adolescents and adults. To accurately target the underlying, patient-specific etiology, it is crucial we understand if age-of-pain-onset influences maltracking.

METHODS

Twenty adolescents (13.9 ± 1.4 years) and 20 adults (28.1 ± 4.9 years) female patients with idiopathic patellofemoral pain (age-of-pain-onset: < 14 and > 18 years of age, respectively) formed the patient cohort. Twenty adolescents and 20 adults (matched for gender, age, and body mass index) formed the control cohort. We captured three-dimensional patellofemoral kinematics during knee flexion-extension using dynamic MRI. Patellar maltracking (deviation in patient-specific patellofemoral kinematics, relative to their respective age-controlled mean values) was the primary outcome measure, which was compared between individuals with adolescent-onset and adult-onset patellofemoral pain using ANOVA and discriminant analysis.

FINDINGS

The female adolescent-onset patellofemoral pain cohort demonstrated increased lateral (P = 0.032), superior (P = 0.007), and posterior (P < 0.001) maltracking, with increased patellar flexion (P < 0.001) and medial spin (P = 0.002), relative to the adult-onset patellofemoral pain cohort. Post-hoc analyses revealed increased lateral shift [mean difference ± 95% confidence interval = -2.9 ± 2.1 mm at 10° knee angle], posterior shift [-2.8 ± 2.1 mm, -3.3 ± 2.3 mm & -3.1 ± 2.4 mm at 10°, 20°& 30°], with greater patellar flexion [3.8 ± 2.6 mm & 5.0 ± 2.8 mm, at 20°& 30°] and medial spin [-2.2 ± 1.7 mm & -3.4 ± 2.3 mm at 20°& 30°]. Axial-plane maltracking accurately differentiated the patient age-of-pain-onset (60-75%, P < 0.001).

INTERPRETATION

Age-of-pain-onset influences the maltracking patterns seen in patients with patellofemoral pain; with all, but 1, degree of freedom being unique in the adolescent-onset-patellofemoral pain cohort. Clinical awareness of this distinction is crucial for correctly diagnosing a patient's pain etiology and optimizing interventional strategies.

Patella Apex Influences Patellar Ligament Forces and Ratio

The relationship between three-dimensional shape and patellofemoral mechanics is complicated. The Wiberg patella classification is a method of distinguishing shape differences in the axial plane of the patella that can be used to connect shape differences to observed mechanics. This study uses the Wiberg patella classification to differentiate variance in a statistical shape model describing changes in patella morphology and height. We investigate how patella morphology influences force distribution within the patellofemoral joint. The Wiberg type I patella has a more symmetrical medial and lateral facet while the type III patella has a larger lateral facet compared to medial. The second principal component of the statistical shape model described shape variation that qualitatively resembled the different Wiberg patellas. We generated patellofemoral morphologies from the statistical shape model and integrated them into a musculoskeletal model with a twelve degrees-of-freedom knee. We simulated an overground walking trial with these morphologies and recorded patellofemoral mechanics and ligament forces. An increase in patellar ligament force corresponded with an increase in patella height. Wiberg type III patellas had a sharper patella apex which related to lower ratios of quadriceps tendon forces to patellar ligament forces. The change in pivot point of the patella affects the ratio of forces as well as the patellofemoral reaction force. This study provides a better understanding of how patella morphology affects fundamental patella mechanics which may help identify at-risk populations for pathology development.

Patellofemoral Pain in Adolescents: Understanding Patellofemoral Morphology and Its Relationship to Maltracking

BACKGROUND

Developing bone is highly adaptable and, as such, is susceptible to pathological shape deformation. Thus, it is imperative to quantify if changes in patellofemoral morphology are associated with adolescent-onset patellofemoral pain, as a pathway to improve our understanding of this pain's etiology.

PURPOSE

To quantify and compare patellofemoral morphology in adolescent patients with patellofemoral pain with matched healthy adolescent controls and determine if a relationship exists between patellofemoral shape and kinematics (measured during active flexion-extension).

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Using 3-dimensional static magnetic resonance images acquired during a previous study, we measured patellar, trochlear, and lateral patellar width; trochlear and patellar depth; Wiberg index; patellar-height ratio; lateral trochlear inclination; cartilage length; and lateral femoral shaft length. Student t test was used to compare shape parameters between adolescents with patellofemoral pain and controls. Pearson correlations and stepwise linear regression models were used to explore the relationship among morphology, kinematics (medial-lateral shift/tilt), and pain.

RESULTS

Relative to controls, adolescents with patellofemoral pain had larger sulci (mean ± SD, 6.6 ± 0.7 vs 6.0 ± 1.1 mm; 95% CI, 0.6 mm; P = .043; d = 0.66), lateral patellar width (23.1 ± 2.4 vs 21.4 ± 2.6 mm; 95% CI, 1.6 mm; P = .033; d = 0.70), and patella-trochlear width ratio (1.2 ± 0.1 vs 1.1 ± 0.1; 95% CI, 0.1; P < .001; d = 1.26). Shape correlated with kinematics in both cohorts and in the entire population. In the patellofemoral pain group, lateral shaft length (r = 0.518; P = .019), Wiberg index (r = 0.477; P = .033), and patellar-height ratio (r = -0.582; P = .007) were correlated with medial shift. A moderate correlation existed between patellar-height ratio and lateral patellar tilt (r = 0.527; P = .017). Half of the variation in patellar shift in the patellofemoral pain cohort was explained by the patellar-height ratio and Wiberg index (R² = 0.487; P = .003). Linear correlations with pain were not found.

CONCLUSION

This study provides direct evidence that patellofemoral morphology is altered and influences maltracking in adolescents with patellofemoral pain, highlighting the multifactorial etiology of this pain. Neither morphology nor kinematics (measured during active flexion-extension) correlated with pain. Both increases and decreases in these parameters likely lead to pain, negating a direct linear correlation.

Patellar Maltracking Persists in Adolescent Females With Patellofemoral Pain: A Longitudinal Study

Background:

Patellofemoral pain is one of the most common conditions seen in sports medicine practices, particularly among adolescent females. However, the natural history of the underlying pathology in patellofemoral pain during puberty remains poorly understood.

Purpose:

The purpose of this longitudinal study is to assess changes in patellar maltracking patterns in subjects with patellofemoral pain as they mature from mid- to late adolescence.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Three-dimensional patellofemoral kinematic data were acquired during active knee extension-flexion using dynamic magnetic resonance imaging in 6 girls (10 knees; mean age, 14.0 years) with clinically diagnosed patellofemoral pain. The subjects then returned as late adolescents (mean age, 18.5 years) for follow-up scanning. Three-dimensional patellofemoral kinematic parameters were evaluated across the range of motion, but comparison between time points was restricted to 10° of flexion. Participation in impact and nonimpact physical activities, pain score based on the visual analog scale, and the anterior knee pain score were also compared across initial and follow-up visits.

Results:

All subjects reported improved patellofemoral pain symptoms at follow-up, and one subject reported complete resolution. However, relative to the initial visit, no differences were found in patellar maltracking. There was a decrease in hours engaged in impact physical activities for all subjects at follow-up.

Conclusion:

This study provides insight into the natural history of patellofemoral pain in adolescent females. The relatively unchanged patellofemoral maltracking across subjects suggests that potential anatomic and kinematic abnormalities contributing to patellofemoral pain during mid-adolescence persist during skeletal maturation. Symptom improvement for these subjects did not result from a change in patellofemoral tracking, but rather from other causes.

Effects of surgical intervention on trochlear remodeling in pediatric patients with recurrent patella dislocation cases

Patella instability is often encountered among physically active pediatric athletes, and surgical intervention is useful in cases with recurrent patella dislocations, chronic instability, and abnormal alignment. Several surgical procedures have been used for patella-realignment and stabilization, but the effects of surgical intervention on bony trochlear remodeling in skeletally immature patients have not been well studied. We thus present two cases of pediatric recurrent patella dislocations that showed trochlear remodeling following patella-realignment surgery. The first case describes an 11-year-old female treated with a Roux-Golthwait procedure and the second case highlights a 12-year-old male treated with lateral release and medial capsular reefing. The Merchant technique, a radiographic criterion that was designed to evaluate patella alignment in relation to the femoral trochlea groove, including sulcus and congruence angles was used to measure postoperative bony development. Both pediatric patients showed successful outcomes following surgical interventions for chronic patella instability. Using the Merchant technique, both patients showed improved congruence and sulcus angles postoperatively. Patella realignment in skeletally immature patients may be beneficial for promoting trochlear remodeling and deepening of the trochlear groove, which may help protect against future dislocation or subluxation events.

LEVEL OF EVIDENCE

Level IV, case report.

Effectiveness of goosestep training or its modification on treating patellar malalignment syndrome: clinical, radiographic, and electromyographic studies

INTRODUCTION

Imbalanced soft tissue tension between medial and lateral para-patellar structures is the most common pathogenic cause of patellar malalignment syndrome. Despite the fact that an effective technique has not been developed, this disorder is usually treated conservatively. This prospective study tried to identify an effective alternative treatment for patellar malalignment syndrome.

MATERIALS AND METHODS

Forty female patients (age, 20-40 years) with bilateral patellar malalignment syndrome were randomly divided into two groups. Forty knees in 20 patients were treated with goosestep training without forcefully striking the ground, and 40 knees in other 20 patients were treated with goosestep training with forcefully striking the ground.

RESULTS

After 1 month, significant clinical improvement was observed in 72.5% of all patients (P < 0.001). Congruence or lateral patellofemoral angles and VMO/VL (vastus medialis obliquus/vastus lateralis) ratio significantly improved within 1 or 3 months in both groups (P < 0.001 for each comparison).

CONCLUSION

Goosestep training with or without forcefully striking the ground is a feasible method for treating patellar malalignment syndrome. The main advantages include its convenience, simplicity, lack of cost, and demonstrated effectiveness.

Dimorphism and patellofemoral disorders

Sex is defined as the classification of living things according to their chromosomal compliment. Gender is defined as a person's self-representation as a male or female or how social institutions respond to that person on the basis of his or her gender presentation. One frequently divides the topic or dimorphism into the biologic response inherent in their sex and the environmental response that might be better termed "gender differences." Clinicians have anecdotally agreed for years that patellofemoral disorders are more common in women. Given the difficulty in classifying patellofemoral disorders, literature support for this assumption is meager. For the purposes of this article we divide patellofemoral disorders into three categories: patellofemoral pain, patellofemoral instability, and patellofemoral arthritis. possible sex difference in these disorders are reviewed.

The role of hip muscle function in the treatment of patellofemoral pain syndrome

BACKGROUND

Previous literature has associated hip weakness with patellofemoral pain syndrome.

HYPOTHESIS

Improvements in hip strength and flexibility are associated with a decrease in patellofemoral pain.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Thirty-five patients with patellofemoral pain syndrome, aged 33 +mn; 16 years (29 women, 6 men; 43 knees), were evaluated and placed on a 6-week treatment program. Hip flexion, abduction, and adduction strengths, Thomas and Ober test results, and visual analog scale scores for pain with activities of daily living as well as with exercise were documented on initial evaluation and again 6 weeks later. Treatment consisted of strength and flexibility exercises primarily focusing on the hip.

RESULTS

Hip flexion strength improved by 35% +/- 8.4% in 26 lower extremities treated successfully, compared with -1.8% +/- 3.5% in 17 lower extremities with an unsuccessful outcome (P < .001). Before treatment, there were positive Ober test results in 39 of 43 lower extremities; positive Thomas test results were seen in 31 of 43 lower extremities. A successful outcome with a concurrent normalized Ober test result was seen in 83% (20/24) of lower extremities, and successful outcomes with normalized Thomas test results were seen in 80% (16/20) of lower extremities. A combination of improved hip flexion strength (> 20%) as well as normal Ober and Thomas test results was seen in 93% of successfully treated cases (14/15 lower extremities), compared with 0% success (0/5 lower extremities) if there was no change in hip flexion strength (< 20%) and if Ober and Thomas test results remained positive.

CONCLUSIONS

Improvements in hip flexion strength combined with increased iliotibial band and iliopsoas flexibility were associated with excellent results in patients with patellofemoral pain syndrome.

Patellofemorales Schmerzsyndrom

The patellofemoral pain syndrome is of high socioeconomic relevance as it most frequently occurs in young working patients. As its etiology is often unknown there is no standard treatment protocol. Several studies analyzed the different causes of patellofemoral pain and their different therapies. Static problems (pes planovalgus, instabilities, leg length differences) or chronic overuse of the knee extensor mechanism have to be identified and treated. After exclusion of intra-articular pathologies, the treatment of patellofemoral pain syndrome begins with conservative management. Stretching of the flexor and extensor muscles and training of the quadriceps muscle are the main approaches. If conservative treatment fails and patellofemoral pain persists, there are several surgical procedures for realignment of the patella in the trochlear groove and reduction of the patellofemoral pressure. Overweight patients exhibit chronic mechanical overuse of the patellofemoral joint. This leads to a higher rate of cartilage degeneration and problems at the inserting tendons and stabilizing tissues.

The influence of gender and age on hamstring muscle length in healthy adults

STUDY DESIGN

Cross-sectional descriptive study.

OBJECTIVES

To examine the factors of gender and age, stratified by 10-year increments, on hamstring muscle length (HML) as measured by passive straight-leg raise (PSLR) and popliteal angle (PA).

BACKGROUND

Differences in HML between men and women have not been examined for a large group of healthy adults over a wide range of ages. The usefulness of these data is to provide some typical values of HML for future reference.

METHODS AND MEASURES

Two hundred fourteen adults (108 women, 106 men; age range, 20-79 years) with no known history of hip or knee joint disease and no history of recent hamstring strain participated in the study. PSLR (trunk-thigh angle) and PA (thigh-leg angle) were estimated with a goniometer. A 2-way analysis of variance (ANOVA) was used to analyze the effects of 2 independent variables (gender and age) on 2 dependent variables (PSLR and PA). Statistical significance was established at alpha<.05.

RESULTS

HML differed significantly (P<.001) between genders for both methods of measurement, with females demonstrating greater flexibility than their male counterparts. The difference between genders was 8 degrees for PSLR and 11 degrees for PA. HML was not influenced by age.

CONCLUSIONS

This study provides physical therapists with typical values of HML in healthy men and women.

Identification of Individuals With Patellofemoral Pain Whose Symptoms Improved After a Combined Program of Foot Orthosis Use and Modified Activity: A Preliminary Investigation

Background and Purpose. In patients with patellofemoral pain syndrome (PFPS), the authors determined which aspects of the examination could be used to identify those patients most likely to respond to off-the-shelf foot orthoses and instruction in activity modification. Participants and Methods. Fifty participants were enrolled in the study, and data for 5 individuals were excluded from analysis. Thirty-four men and 11 women completed the study. Participants were given foot orthoses and instructed in activity modification for 3 weeks. A 50% reduction in pain was considered a success. Likelihood ratios (LRs) were computed to determine which examination findings were most predictive of success. Results. The best predictors of improvement were forefoot valgus alignment of ≥2 degrees (+LR=4.0, 95% confidence interval [CI]=0.7–21.9), great toe extension of ≤78 degrees (+LR=4.0, 95% CI=0.7–21.9), and navicular drop of ≤3 mm (+LR=2.4, 95% CI=1.3–4.3). Discussion and Conclusion. The results suggest that patients with PFPS who have forefoot valgus alignment of ≥2 degrees, passive great toe extension of ≤78 degrees, or navicular drop of ≤3 mm are most likely to respond favorably to initial intervention with an off-the-shelf foot orthosis and instruction in activity modification.

Patellar taping: is clinical success supported by scientific evidence?

Patellofemoral pain syndrome (PFPS) is a common condition presenting to physiotherapy and sports medicine practices. Despite its prevalence, the aetiology, pathogenesis, and recommended treatment remain unclear. One component of treatment for PFPS that has been subjected to scrutiny is patellar taping. This taping was designed to realign the patella within the femoral trochlea, thus reducing pain from PFPS and improving both quadriceps and patellofemoral joint function. Clinical and research findings confirm that the pain associated with PFPS is significantly reduced with patellar taping. Therefore, research has aimed at determining the mechanisms of this pain relief. The means by which patellar tape can relieve pain may provide insight into the aetiology and risk factors for PFPS, thus allowing more appropriately designed treatment regimes and preventative strategies. There is evidence to suggest that patellar tape improves patella alignment (measured radiographically) and quadriceps function (torque production and extensor moments). Evidence that patellar tape enhances the activation of individual vastii (magnitude or timing) is limited in quality and quantity, which probably reflects the difficulties inherent in measuring this complex question. There is preliminary evidence for improved knee control during gait in association with patellar tape. This paper critically reviews the studies that have examined the effects of patellar taping and makes informed recommendations for further research and clinical practice.

Patellofemoral pain syndrome in the female athlete

Although PFS will continue to be a therapeutic challenge, the prognosis for most female athletes is good, especially if they are motivated and compliant with their treatment program. Particularly in women, care should be taken to avoid placing too much emphasis on biomechanical variants that may not be clinically significant or correctable because such findings can reinforce a feeling that "nothing can be done." In many cases, muscle dysfunction and repetitive loading of the patellofemoral joint rather than fixed biomechanical factors contribute to the development of PFS. Nonetheless, the importance of a detailed biomechanical assessment on physical examination must not be neglected, particularly in athletes who are not improving with conservative treatment and who may become surgical candidates. A practical initial treatment program for most athletes with nontraumatic PFS begins with relative rest, quadriceps strengthening, and stretching of tight myotendinous units. The introduction of NSAIDs, orthoses, taping, knee sleeves, and more specific rehabilitative exercises should be an individualized decision based on physical findings, past treatment results, and athletic expectations. Surgical referral should be considered in cases of PFS or patellar instability refractory to prolonged maximal nonoperative treatment.

Hamstrings and iliotibial band forces affect knee kinematics and contact pattern

Many clinical studies have emphasized the role of the hamstrings and the iliotibial band on knee mechanics, although few biomechanical studies have investigated it. This study therefore examined two hypotheses: (a) with loading of the hamstrings, the tibia translates posteriorly and rotates externally and the tibial contact pattern shifts anteriorly; furthermore, the changes in tibial kinematics alter patellar kinematics and contact; and (b) loading the iliotibial band alters the kinematics and contact pattern of the tibiofemoral joint similarly to loading the hamstrings, and loading the iliotibial band laterally translates the patella and its contact location. Five cadaveric knee specimens were tested with a specially designed knee-joint testing machine in an open-chain configuration. At various flexion angles, the knees were tested always with a quadriceps force but with and without a hamstrings force and with and without an iliotibial band force. The results support the first hypothesis. Hence, the hamstrings may be important anterior and rotational stabilizers of the tibia, a role similar to that of the anterior cruciate ligament. The results also support the second hypothesis, although the iliotibial band force had a smaller effect on the tibia than did the hamstrings force. Both forces also changed patellar kinematics and contact, demonstrating that these structures should also be considered during the clinical management of patellar disorders.

Patellofemoral pain syndrome: a review of current issues

There is no clear consensus in the literature concerning the terminology, aetiology and treatment for pain in the anterior part of the knee. The term 'anterior knee pain' is suggested to encompass all pain-related problems. By excluding anterior knee pain due to intra-articular pathology, peripatellar tendinitis or bursitis, plica syndromes, Sinding Larsen's disease, Osgood Schlatter's disease, neuromas and other rarely occurring pathologies, it is suggested that remaining patients with a clinical presentation of anterior knee pain could be diagnosed with patello-femoral pain syndrome (PFPS). Three major contributing factors of PFPS are discussed: (i) malalignment of the lower extremity and/or the patella; (ii) muscular imbalance of the lower extremity; and (iii) overactivity. The significance of lower extremity alignment factors and pathological limits needs further investigation. It is possible that the definitions used for malalignment should be re-evaluated, as the scientific support is very weak for determining when alignment is normal and when there is malalignment. Consequently, pathological limits must be clarified, along with evaluation of risk factors for acquiring PFPS. Muscle tightness and muscular imbalance of the lower extremity muscles with decreased strength due to hypotrophy or inhibition have been suggested, but remain unclear as potential causes of PFPS. Decreased knee extensor strength is a common finding in patients with PFPS. Various patterns of weaknesses have been reported, with selective weakness in eccentric muscle strength, within the quadriceps muscle and in terminal knee extension. The significance of muscle function in a closed versus open kinetic chain has been discussed, but is far from well investigated. It is clear that further studies are necessary in order to establish the significance of various strength deficits and muscular imbalances, and to clarify whether a specific disturbance in muscular activation is a cause or an effect (or both) of PFPS. The most common symptoms in patients with PFPS are pain during and after physical activity, during bodyweight loading of the lower extremities in walking up/down stairs and squatting, and in sitting with the knees flexed. However, the source of patellofemoral pain in patients with PFPS cannot be sufficiently explained. There are several types of clinical manifestation of pain, and therefore a differentiated documentation of the patient's pain symptoms is necessary. The connection between strength, pain and inhibition, as well as between personality and pain, needs further investigation. Many different treatment protocols are described in the literature and recent studies advocate a comprehensive treatment approach allowing for an individual and specifically designed treatment. Surgical treatment is rarely indicated. It is strongly suggested that, when presenting studies on PFPS, a detailed description should be provided of the diagnosis, inclusion and exclusion criteria of the patients should be specified along with a detailed methodology, and the conclusions drawn should be compared with those of other studies in the published literature. As this is not the case in most studies on PFPS found in the literature, it is only possible to make general comparisons. In order to further develop treatment models for PFPS we advocate prospective, randomised, controlled, long term studies using validated outcome measures. However, there is a strong need for basic research on the nature and aetiology of PFPS in order to better understand this mysterious syndrome.

Which factors predict the long-term outcome in chronic patellofemoral pain syndrome? A 7-yr prospective follow-up study

PURPOSE

The aim of this prospective study was to determine which factors predict the long-term (7-yr) outcome of conservative treatment of chronic patellofemoral pain syndrome.

METHODS

The general predictors registered were age, gender, body composition, athletic activity, duration of symptoms, and follow-up time. The remaining 13 predictors were clinical or radiological measurements of the knee joint. In 45 consecutive patients, these predictors were measured at the beginning of the 6-wk treatment protocol (rest, NSAID, and intense isometric quadriceps exercises) and at the end of the follow-up. The outcome criteria were the 100-mm Visual Analog Scale (VAS) pain score, and the Lysholm and Tegner functional knee scores.

RESULTS

The extension strength of the affected knee was a significant predictor of the outcome scores (Lysholm score: r = 0.37, P < 0.05, and the Tegner score: r = 0.39, P < 0.01): the smaller the strength difference between the affected and unaffected knee, the better the outcome. In a multiple stepwise regression analysis, the variables pain in the patella apprehension test, patella crepitation at baseline and at follow-up, bilateral symptoms developed during the follow-up, and patient's age and height were also independent predictors of the final outcome and could together account 60% for the variation seen in the Lysholm score and 52% in the Tegner score, respectively. Neither the radiologic nor the magnetic resonance imaging changes at the affected knee had a clear association with the 7-yr outcome.

CONCLUSIONS

The results of the current and our previous (15) observations support the concept that restoration of good quadriceps strength and function to the affected extremity is important for good recovery of the patient. In addition, negative findings in the clinical tests of patellar pain and crepitation, nonappearance of bilateral symptoms during the follow-up, low body height, and young age are associated with good long-term outcome.

An evaluation of knee extensor and knee flexor torques and EMGs in patients with patellofemoral pain syndrome in comparison with matched controls

The relationship between concentric and eccentric isokinetic torques and EMGs of quadriceps and hamstring muscles in patients with unilateral patellofemoral pain was studied in 27 patients (13 males, 14 females). The patients and a group of controls matched for age, gender, and physical activity were tested on a Kin-Com dynamometer at 60 degrees/s and 180 degrees/s angular velocity. EMGs were recorded for eight of the patients and their matched controls. In addition, the reproducibility of isokinetic measurements made under the same conditions but on different occasions in patients with patellofemoral pain was evaluated. Twenty-one patients (11 males, 10 females) underwent testing of their quadriceps and hamstring muscles two or three times on a Kin-Com dynamometer. This was performed both concentrically and eccentrically in their painful leg while the patients evaluated their knee pain using Borg's pain scale. The data show that the patients had a significantly lower agonist as well as antagonist EMG activity during knee extension measurements in their painful leg compared with the controls. However, there were no differences in either agonist or antagonist EMG activities during knee flexion measurements between the patients and the controls. The quadriceps muscle torque was considerably weaker in the patients' painful leg compared with both their asymptomatic leg and with the controls. Peak torque for knee extension was reached at a mean of 66 degrees of knee flexion for both patients and controls. However, the patients showed a considerably wider range within which they produced their peak torque in their painful leg than in their asymptomatic and also in comparison with the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrical stimulation of vastus medialis and stretching of lateral thigh muscles in patients with patello-femoral symptoms

Thirty patients with unilateral patello-femoral symptoms and a hypotrophic vastus medialis muscle were treated with transcutaneous electrical stimulation of the vastus medialis obliquus and stretching of the lateral thigh muscles twice daily for 10 weeks. Before and after treatment the position of the patella at fixed knee flexion angles and the area of the vastus medialis and vastus lateralis muscles were studied by computed tomography. Isokinetic quadriceps torque was registered with a Cybex II Dynamometer. An evaluation with a functional knee score was carried out. The healthy contralateral leg served as control in all the examinations. Clinically two-thirds of the patients had improved after 10 weeks of treatment and this improvement remained at follow-up 3.5 years later. The area of the vastus medialis and the quadriceps torque of the treated leg increased significantly, while the area of the vastus lateralis and the position of patella did not change. We conclude that transcutaneous electrical muscle stimulation of the vastus medialis and stretching of the lateral thigh muscles might be of benefit in patients with patello-femoral symptoms and a hypotrophic vastus medialis. An improvement after 10 weeks of treatment seems to predict a good long-term result.

Isokinetic quadriceps training in patients with patellofemoral pain syndrome

The aims of the present investigation were (a) to evaluate the effect of eccentric quadriceps training in patients with unilateral patellofemoral pain and (b) to compare the effect of eccentric and concentric quadriceps training in patients with bilateral patellofemoral pain. Fifteen patients (9 male and 6 female, aged 17-36 years with a mean of 27.5 years) participated in this study. Nine patients had unilateral pain and trained their painful leg eccentrically, while six had bilateral pain and trained one leg eccentrically and the other concentrically. Quadriceps muscle training was performed on a Kin-Com dynamometer at 90 degrees/s and 120 degrees/s angular velocity twice a week for 8 weeks. Before and after the treatment period the thigh muscle torques were measured on the Kin-Com dynamometer at 60 degrees/s, 90 degrees/s, 120 degrees/s and 180 degrees/s for quadriceps and at 60 degrees/s and 180 degrees/s for hamstrings. Nine controls, matched for gender and age with the group with unilateral pain, were tested in the same way on the Kin-Com dynamometer. For functional evaluation a knee score was calculated before training, after 8 weeks of training and at a mean of 3.4 years after completion of the training. After 8 weeks of training and at follow-up times of 1 and 3.4 years the patients were also questioned regarding whether or not they felt improvement from the training programme. To determine the degree of knee pain during the training Borg's pain scale was used. The results showed that, compared with the controls, the patients had a significantly lower knee extensor torque in their painful leg at all velocities measured.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of taping the patella on concentric and eccentric torque and EMG of knee extensor and flexor muscles in patients with patellofemoral pain syndrome

The acute effect of patella taping on torque and electromyographic (EMG) activity in maximal voluntary concentric and eccentric action of the knee extensor and flexor muscles in patients with patellofemoral pain syndrome was studied in 48 patients (62 knees). The patients (28 female, 20 male) were tested concentrically and eccentrically on a Kin-Com dynamometer with simultaneous EMG recording with the patella untaped and medially or laterally taped. Patients with clinically normal patellar mobility did not improve their quadriceps performance by taping of the patella; after medial taping they decreased their muscle torque during concentric work at 60 degrees/s (P < 0.05) and eccentric work at 180 degrees/s (P < 0.05). After lateral taping they decreased their muscle torque during concentric work at 60 degrees/s (P < 0.05) and eccentric work at both 60 degrees/s (P < 0.01) and 180 degrees/s (P < 0.05). Moreover, these patients also decreased their agonist EMG activity during concentric work at 60 degrees/s (P < 0.05) and 180 degrees/s (P < 0.05) and their antagonist EMG activity during eccentric work at 60 degrees/s (P < 0.01). Patients with a clinical lateral patellar hypermobility increased their knee extensor torque after medial taping at 60 degrees/s during both eccentric work (P < 0.01) and concentric work (P < 0.05). The greatest improvement in quadriceps performance, however, was in patients with a clinical medial patellar hypermobility. They increased their knee extensor torque after lateral taping during eccentric work at both 60 degrees/s (P < 0.001) and 180 degrees/s (P < 0.001) and during concentric work at 60 degrees/s (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)