Anterior knee pain: a clinical comparison of rehabilitation methods

Motor Control Exercises Compared to Strengthening Exercises for Upper- and Lower-Extremity Musculoskeletal Disorders: A Systematic Review With Meta-Analyses of Randomized Controlled Trials

OBJECTIVE

The purpose of this review was to compare the efficacy of motor control exercises (MCEs) to strengthening exercises for adults with upper- or lower-extremity musculoskeletal disorders (MSKDs).

METHODS

Electronic searches were conducted up to April 2020 in Medline, Embase, Cochrane CENTRAL, and CINAHL. Randomized controlled trials were identified on the efficacy of MCEs compared to strengthening exercises for adults with upper- or lower-extremity MSKDs. Data were extracted with a standardized form that documented the study characteristics and results. For pain and disability outcomes, pooled mean differences (MDs) and standardized mean differences (SMDs) were calculated using random-effects inverse variance models.

RESULTS

Twenty-one randomized controlled trials (n = 1244 participants) were included. Based on moderate-quality evidence, MCEs lead to greater pain (MD = -0.41 out of 10 points; 95% CI = -0.72 to -0.10; n = 626) and disability reductions (SMD = -0.28; 95% CI = -0.43 to -0.13; n = 713) when compared to strengthening exercises in the short term; these differences are not clinically important. When excluding trials on osteoarthritis (OA) participants and evaluating only the trials involving participants with rotator cuff-related shoulder pain, shoulder instability, hip-related groin pain, or patellofemoral pain syndrome, there is moderate quality evidence that MCEs lead to greater pain (MD = -0.74 out of 10 points; 95% CI = -1.22 to -0.26; n = 293) and disability reductions (SMD = -0.40; 95% CI = -0.61 to -0.19; n = 354) than strengthening exercises in the short term; these differences might be clinically important.

CONCLUSIONS

MCEs lead to statistically greater pain and disability reductions when compared to strengthening exercises among adults with MSKDs in the short term, but these effects might be clinically important only in conditions that do not involve OA. Inclusion of new trials might modify these conclusions.

IMPACT

These results suggest that MCEs could be prioritized over strengthening exercises for adults with the included non-OA MSKDs; however, results are unclear for OA disorders.

Health Economic Evaluations of Hip and Knee Interventions in Orthopaedic Sports Medicine: A Systematic Review and Quality Assessment

BACKGROUND

The economic burden of musculoskeletal diseases is substantial and growing. Economic evaluations compare costs and health benefits of interventions simultaneously to help inform value-based care; thus, it is crucial to ensure that studies are using appropriate methodology to provide valid evidence on the cost-effectiveness of interventions. This is particularly the case in orthopaedic sports medicine, where several interventions of varying costs are available to treat common hip and knee conditions.

PURPOSE

To summarize and evaluate the quality of economic evaluations in orthopaedic sports medicine for knee and hip interventions and identify areas for quality improvement.

STUDY DESIGN

Systematic review; Level of evidence, 3.

METHODS

The Medline, AMED, OVID Health Star, and EMBASE databases were searched from inception to March 1, 2020, to identify economic evaluations that compared ≥2 interventions for hip and/or knee conditions in orthopaedic sports medicine. We assessed the quality of full economic evaluations using the Quality of Health Economic Studies (QHES) tool, which consists of 16 questions for a total score of 100. We classified studies into quartiles based on QHES score (extremely poor quality to high quality) and we evaluated the frequency of studies that addressed each of the 16 QHES questions.

RESULTS

A total of 93 studies were included in the systematic review. There were 41 (44%) cost analyses, of which 21 (51%) inappropriately concluded interventions were cost-effective. Only 52 (56%) of the included studies were full economic evaluations, although 40 of these (77%) fell in the high-quality quartile. The mean QHES score was 83.2 ± 19. Authors consistently addressed 12 of the QHES questions; questions that were missed or unclear were related to statistical uncertainty, appropriateness of costing methodology, and discussion of potential biases. The most frequently missed question was whether the cost perspective of the analysis was stated and justified.

CONCLUSION

The number of studies in orthopaedic sports medicine is small, despite their overall good quality. Yet, there are still many highly cited studies based on low-quality or partial economic evaluations that are being used to influence clinical decision-making. Investigators should follow international health economic guidelines for study design and critical appraisal of studies to further improve quality.

National Athletic Trainers' Association Position Statement: Management of Individuals With Patellofemoral Pain

OBJECTIVE: 

To present recommendations for athletic trainers and other health care providers regarding the identification of risk factors for and management of individuals with patellofemoral pain (PFP).

BACKGROUND: 

Patellofemoral pain is one of the most common knee diagnoses; however, this condition continues to be one of the most challenging to manage. Recent evidence has suggested that certain risk factors may contribute to the development of PFP. Early identification of risk factors may allow clinicians to develop and implement programs aimed at reducing the incidence of this condition. To date, clinicians have used various treatment strategies that have not necessarily benefitted all patients. Suboptimal outcomes may reflect the need to integrate clinical practice with scientific evidence to facilitate clinical decision making.

RECOMMENDATIONS: 

The recommendations are based on the best available evidence. They are intended to give athletic trainers and other health care professionals a framework for identifying risk factors for and managing patients with PFP.

Effectiveness of Manual Therapy for Pain and Self-reported Function in Individuals With Patellofemoral Pain: Systematic Review and Meta-analysis

Study Design Systematic literature review with meta-analysis. Background Management of patellofemoral pain (PFP) may include the utilization of manual therapy (MT) techniques to the patellofemoral joint, surrounding soft tissues, and/or lumbopelvic region. Objectives To determine the effectiveness of MT, used alone or as an adjunct intervention, compared to standard treatment or sham for reducing pain and improving self-reported function in individuals with PFP. Methods An electronic literature search was conducted in the PubMed, Ovid, Cochrane Central Register of Controlled Trials, and CINAHL databases for studies investigating MT for individuals with PFP. Studies published through August 2017 that compared MT (local or remote to the knee), used alone or in combination with other interventions, to control or sham interventions were included. Patient-reported pain and functional outcomes were collected and synthesized. Trials were assessed via the Cochrane risk-of-bias tool, and a meta-analysis of the evidence was performed. Results Nine studies were included in the review, 5 of which were rated as having a low risk of bias. The use of MT, applied to the local knee structure, was associated with favorable short-term changes in self-reported function and pain in individuals with PFP, when compared to a comparison (control or sham) intervention. However, the changes were clinically meaningful only for pain (defined as a 2-cm or 2-point improvement on a visual analog scale or numeric pain-rating scale). The evidence regarding lumbopelvic manipulation was inconclusive for pain improvement in individuals with PFP, based on 3 studies. Conclusion The data from this review cautiously suggest that MT may be helpful in the short term for decreasing pain in patients with PFP. Several studies integrated MT into a comprehensive treatment program. Changes in self-reported function with the inclusion of MT were shown to be significant, but not clinically meaningful. The limitations in the studies performed to date suggest that future research should determine the optimal techniques and dosage of MT and perform longer follow-up to monitor long-term effects. Level of Evidence Therapy, level 1a. J Orthop Sports Phys Ther 2018;48(5):358-371. Epub 6 Jan 2018. doi:10.2519/jospt.2018.7243.

Bilateral Anterior Knee Pain in a High School Cross-Country Runner: An Atypical Etiology

Anterior knee pain is a common complaint found in distance runners, and can be the end result of a variety of benign processes. A 17-year-old female cross-country runner presented to a sports medicine clinic with insidious onset of bilateral patellofemoral pain (PFP). In the workup of the significant quadriceps weakness discovered on her initial examination, a principal contributing cause of her PFP, she was found to have a form of spinal muscular atrophy, an uncommon neurodegenerative disease that typically requires multidisciplinary medical care. Her case provides a good example for clinicians to consider, at times, an in-depth assessment of the root causes of benign conditions.

WITHDRAWN: Exercise therapy for patellofemoral pain syndrome

The review was withdrawn, as of Issue 1, 2015, because it has been superceded by a new Cochrane review: van der Heijden RA, Lankhorst NE, van Linschoten R, Bierma‐Zeinstra SMA, van Middelkoop M. Exercise for treating patellofemoral pain syndrome. Cochrane Database of Systematic Reviews 2015, Issue 1. Art. No.: CD010387. DOI: 10.1002/14651858.CD010387.pub2.

The editorial group responsible for this previously published document have withdrawn it from publication.

Exercise for treating patellofemoral pain syndrome

BACKGROUND

Patellofemoral pain syndrome (PFPS) is a common knee problem, which particularly affects adolescents and young adults. PFPS, which is characterised by retropatellar (behind the kneecap) or peripatellar (around the kneecap) pain, is often referred to as anterior knee pain. The pain mostly occurs when load is put on the knee extensor mechanism when climbing stairs, squatting, running, cycling or sitting with flexed knees. Exercise therapy is often prescribed for this condition.

OBJECTIVES

To assess the effects (benefits and harms) of exercise therapy aimed at reducing knee pain and improving knee function for people with patellofemoral pain syndrome.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (May 2014), the Cochrane Central Register of Controlled Trials (2014, Issue 4), MEDLINE (1946 to May 2014), EMBASE (1980 to 2014 Week 20), PEDro (to June 2014), CINAHL (1982 to May 2014) and AMED (1985 to May 2014), trial registers (to June 2014) and conference abstracts.

SELECTION CRITERIA

Randomised and quasi-randomised trials evaluating the effect of exercise therapy on pain, function and recovery in adolescents and adults with patellofemoral pain syndrome. We included comparisons of exercise therapy versus control (e.g. no treatment) or versus another non-surgical therapy; or of different exercises or exercise programmes.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials based on pre-defined inclusion criteria, extracted data and assessed risk of bias. Where appropriate, we pooled data using either fixed-effect or random-effects methods. We selected the following seven outcomes for summarising the available evidence: pain during activity (short-term: ≤ 3 months); usual pain (short-term); pain during activity (long-term: > 3 months); usual pain (long-term); functional ability (short-term); functional ability (long-term); and recovery (long-term).

MAIN RESULTS

In total, 31 heterogeneous trials including 1690 participants with patellofemoral pain are included in this review. There was considerable between-study variation in patient characteristics (e.g. activity level) and diagnostic criteria for study inclusion (e.g. minimum duration of symptoms) and exercise therapy. Eight trials, six of which were quasi-randomised, were at high risk of selection bias. We assessed most trials as being at high risk of performance bias and detection bias, which resulted from lack of blinding.The included studies, some of which contributed to more than one comparison, provided evidence for the following comparisons: exercise therapy versus control (10 trials); exercise therapy versus other conservative interventions (e.g. taping; eight trials evaluating different interventions); and different exercises or exercise programmes. The latter group comprised: supervised versus home exercises (two trials); closed kinetic chain (KC) versus open KC exercises (four trials); variants of closed KC exercises (two trials making different comparisons); other comparisons of other types of KC or miscellaneous exercises (five trials evaluating different interventions); hip and knee versus knee exercises (seven trials); hip versus knee exercises (two studies); and high- versus low-intensity exercises (one study). There were no trials testing exercise medium (land versus water) or duration of exercises. Where available, the evidence for each of seven main outcomes for all comparisons was of very low quality, generally due to serious flaws in design and small numbers of participants. This means that we are very unsure about the estimates. The evidence for the two largest comparisons is summarised here. Exercise versus control. Pooled data from five studies (375 participants) for pain during activity (short-term) favoured exercise therapy: mean difference (MD) -1.46, 95% confidence interval (CI) -2.39 to -0.54. The CI included the minimal clinically important difference (MCID) of 1.3 (scale 0 to 10), indicating the possibility of a clinically important reduction in pain. The same finding applied for usual pain (short-term; two studies, 41 participants), pain during activity (long-term; two studies, 180 participants) and usual pain (long-term; one study, 94 participants). Pooled data from seven studies (483 participants) for functional ability (short-term) also favoured exercise therapy; standardised mean difference (SMD) 1.10, 95% CI 0.58 to 1.63. Re-expressed in terms of the Anterior Knee Pain Score (AKPS; 0 to 100), this result (estimated MD 12.21 higher, 95% CI 6.44 to 18.09 higher) included the MCID of 10.0, indicating the possibility of a clinically important improvement in function. The same finding applied for functional ability (long-term; three studies, 274 participants). Pooled data (two studies, 166 participants) indicated that, based on the 'recovery' of 250 per 1000 in the control group, 88 more (95% CI 2 fewer to 210 more) participants per 1000 recovered in the long term (12 months) as a result of exercise therapy. Hip plus knee versus knee exercises. Pooled data from three studies (104 participants) for pain during activity (short-term) favoured hip and knee exercise: MD -2.20, 95% CI -3.80 to -0.60; the CI included a clinically important effect. The same applied for usual pain (short-term; two studies, 46 participants). One study (49 participants) found a clinically important reduction in pain during activity (long-term) for hip and knee exercise. Although tending to favour hip and knee exercises, the evidence for functional ability (short-term; four studies, 174 participants; and long-term; two studies, 78 participants) and recovery (one study, 29 participants) did not show that either approach was superior.

AUTHORS' CONCLUSIONS

This review has found very low quality but consistent evidence that exercise therapy for PFPS may result in clinically important reduction in pain and improvement in functional ability, as well as enhancing long-term recovery. However, there is insufficient evidence to determine the best form of exercise therapy and it is unknown whether this result would apply to all people with PFPS. There is some very low quality evidence that hip plus knee exercises may be more effective in reducing pain than knee exercise alone.Further randomised trials are warranted but in order to optimise research effort and engender the large multicentre randomised trials that are required to inform practice, these should be preceded by research that aims to identify priority questions and attain agreement and, where practical, standardisation regarding diagnostic criteria and measurement of outcome.

Lower extremity kinematics of females with patellofemoral pain syndrome while stair stepping

STUDY DESIGN

Cross-sectional case-control design.

BACKGROUND

Although the etiology of patellofemoral pain syndrome (PFPS) is not completely understood, there is some evidence to suggest that hip position during weight-bearing activities contributes to the disorder.

OBJECTIVE

To compare the knee and hip motions (and their coordination) during stair stepping in female athletes with and without PFPS.

METHODS

Two groups of female recreational athletes, 1 group with PFPS (n = 10) and a control group without PFPS (n = 10), were tested. All participants ascended and descended stairs (condition) at 2 speeds (self-selected comfortable and taxing [defined as 20% faster than the comfortable speed]), while the knee and hip angles were measured with a magnetic-based kinematic data acquisition system. Angle-angle diagrams were used to examine the relationship between flexion/extension of the knee and flexion/extension, adduction/abduction, and internal/external rotation of the hip. The angle of the knee and the 3 angles of the hip at foot contact on the third step were compared between groups by means of 3-way analyses of variance (ANOVA), with repeated measures on speed and condition.

RESULTS

Group-by-speed interaction for knee angle was significant, with knee flexion being greater for the PFPS group for stair ascent and descent at a comfortable speed. Both the angle-angle diagrams and ANOVA demonstrated greater adduction and internal rotation of the hip in the individuals with PFPS compared to control participants during stair descent.

CONCLUSION

Compared to control participants, females with PFPS descend stairs with the knee in a more flexed position and have the hip in a more adducted and internally rotated position at foot contact during stair stepping at a comfortable speed.

Cost-effectiveness of interventions based on physical exercise in the treatment of various diseases: A systematic literature review

Objectives:The aim of this study was to review studies reporting cost-effectiveness of exercise-based interventions in treatment of various diseases.

Methods:Systematic literature search using several databases. Abstracts initially screened independently by two authors, full-text articles again evaluated by two authors, who decided whether an article should be included. Included were scientifically valid articles describing controlled studies that included an exercise-based intervention in the treatment of an established medical condition, and also reported on the cost-effectiveness of the intervention, or its effect on the utilization of health services. Quality was assessed with an established approach.

Results:A total of 914 articles were identified, of them 151 were obtained for closer review. Sixty-five articles describing sixty-one studies were included. Most (82 percent) were randomized trials. Twenty-eight studies dealt with musculoskeletal disorders, fifteen with cardiology, four with rheumatic diseases, four with pulmonary diseases, three with urinary incontinence, and two with vascular disorders. There was one study each in the fields of oncology, chronic fatigue, endocrinology, psychiatry, and neurology. Exercise interventions in musculoskeletal disorders were deemed to be cost-effective in 54 percent, in cardiology in 60 percent, and in rheumatic diseases in 75 percent of the cases. There was some evidence that exercise might be cost-effective in intermittent claudication, breast cancer patients, diabetes, and schizophrenia.

Conclusions:The number of studies assessing cost-effectiveness of exercise interventions in various diseases is still limited. The results show large variation but suggest that some exercise interventions can be cost-effective. Most convincing evidence was found for rehabilitation of cardiac and back pain patients; however, even in these cases, the evidence was partly contradictory.

Foot orthoses and physiotherapy in the treatment of patellofemoral pain syndrome: randomised clinical trial

OBJECTIVE

To compare the clinical efficacy of foot orthoses in the management of patellofemoral pain syndrome with flat inserts or physiotherapy, and to investigate the effectiveness of foot orthoses plus physiotherapy.

DESIGN

Prospective, single blind, randomised clinical trial.

SETTING

Single centre trial within a community setting in Brisbane, Australia.

PARTICIPANTS

179 participants (100 women) aged 18 to 40 years, with a clinical diagnosis of patellofemoral pain syndrome of greater than six weeks' duration, who had no previous treatment with foot orthoses or physiotherapy in the preceding 12 months.

INTERVENTIONS

Six weeks of physiotherapist intervention with off the shelf foot orthoses, flat inserts, multimodal physiotherapy (patellofemoral joint mobilisation, patellar taping, quadriceps muscle retraining, and education), or foot orthoses plus physiotherapy.

MAIN OUTCOME MEASURES

Global improvement, severity of usual and worst pain over the preceding week, anterior knee pain scale, and functional index questionnaire measured at 6, 12, and 52 weeks.

RESULTS

Foot orthoses produced improvement beyond that of flat inserts in the short term, notably at six weeks (relative risk reduction 0.66, 99% confidence interval 0.05 to 1.17; NNT 4 (99% confidence interval 2 to 51). No significant differences were found between foot orthoses and physiotherapy, or between physiotherapy and physiotherapy plus orthoses. All groups showed clinically meaningful improvements in primary outcomes over 52 weeks.

CONCLUSION

While foot orthoses are superior to flat inserts according to participants' overall perception, they are similar to physiotherapy and do not improve outcomes when added to physiotherapy in the short term management of patellofemoral pain. Given the long term improvement observed in all treatment groups, general practitioners may seek to hasten recovery by prescribing prefabricated orthoses.

TRIAL REGISTRATION

Australian Clinical Trials Registry ACTRN012605000463673 and ClinicalTrials.gov NCT00118521.

Evaluation of the scope and quality of systematic reviews on nonpharmacological conservative treatment for patellofemoral pain syndrome

STUDY DESIGN

Systematic literature review.

OBJECTIVE

To evaluate the quality and scope of recently published systematic reviews on the topic of patellofemoral pain syndrome (PFPS) and to provide an overview of their findings.

BACKGROUND

PFPS is a commonly treated condition. There is a large body of literature on conservative nonpharmacological interventions for PFPS, including multiple systematic reviews, which require critiquing and summarizing.

METHODS AND MEASURES

A systematic review of systematic reviews on conservative nonpharmacological treatment strategies for PFPS was performed. Published systematic reviews were identified by searching MEDLINE, EMBASE, CINAHL, SPORTDISCUS, Current Contents, The Cochrane Library, and PEDro electronic databases from the year 2000 until May 2007. Cited reference searches of each author in the Web of Science complemented this search. Review quality was evaluated by a specifically designed scale and only high-quality reviews were retained to validate and summarize reported findings.

RESULTS

Ten reviews met the inclusion criteria. Among them, only 3 were considered to be high quality, covering exercise, foot and knee orthoses, and ultrasound intervention for PFPS. None of the 3 reviews included literature published after the year 2001. Some limited evidence for the use of exercise, exercise combined with taping, and exercise combined with the use of a Protonics brace was found for treatment of individuals with PFPS.

CONCLUSION

Published systematic reviews and clinical trials need to be conducted with more rigorous methodological design. There are no up-to-date, high-quality systematic reviews covering conservative nonpharmacological treatments for individuals with PFPS, which indicates that updates in all areas are needed.

Patellofemoral pain syndrome (PFPS): a systematic review of anatomy and potential risk factors

Background

Patellofemoral Pain Syndrome (PFPS), a common cause of anterior knee pain, is successfully treated in over 2/3 of patients through rehabilitation protocols designed to reduce pain and return function to the individual. Applying preventive medicine strategies, the majority of cases of PFPS may be avoided if a pre-diagnosis can be made by clinician or certified athletic trainer testing the current researched potential risk factors during a Preparticipation Screening Evaluation (PPSE). We provide a detailed and comprehensive review of the soft tissue, arterial system, and innervation to the patellofemoral joint in order to supply the clinician with the knowledge required to assess the anatomy and make recommendations to patients identified as potentially at risk. The purpose of this article is to review knee anatomy and the literature regarding potential risk factors associated with patellofemoral pain syndrome and prehabilitation strategies. A comprehensive review of knee anatomy will present the relationships of arterial collateralization, innervations, and soft tissue alignment to the possible multifactoral mechanism involved in PFPS, while attempting to advocate future use of different treatments aimed at non-soft tissue causes of PFPS.

Methods

A systematic database search of English language PubMed, SportDiscus, Ovid MEDLINE, Web of Science, LexisNexis, and EBM reviews, plus hand searching the reference lists of these retrieved articles was performed to determine possible risk factors for patellofemoral pain syndrome.

Results

Positive potential risk factors identified included: weakness in functional testing; gastrocnemius, hamstring, quadriceps or iliotibial band tightness; generalized ligamentous laxity; deficient hamstring or quadriceps strength; hip musculature weakness; an excessive quadriceps (Q) angle; patellar compression or tilting; and an abnormal VMO/VL reflex timing. An evidence-based medicine model was utilized to report evaluation criteria to determine the at-risk individuals, then a defined prehabilitation program was proposed that begins with a dynamic warm-up followed by stretches, power and multi-joint exercises, and culminates with isolation exercises. The prehabilitation program is performed at lower intensity level ranges and can be conducted 3 days per week in conjunction with general strength training. Based on an objective one repetition maximum (1RM) test which determines the amount an individual can lift in good form through a full range of motion, prehabilitation exercises are performed at 50–60% intensity.

Conclusion

To reduce the likelihood of developing PFPS, any individual, especially those with positive potential risk factors, can perform the proposed prehabilitation program.

The influence of patellar bracing on patellar and knee load-distribution and kinematics: an experimental cadaver study

The aim of this study was to analyze the biomechanical consequences of patella bracing in order to evaluate possible mechanisms supporting its clinical application. The hypothesis is that the patellar bracing reduces patellofemoral pressure by influencing patellar and knee kinematics, and load distribution. Physiologic isokinetic knee extension motions were simulated on ten human knee cadaver specimens using a knee kinematic simulator. Joint kinematics were evaluated using an ultrasound-based motion analysis system and patellofemoral contact pressure was measured using a thin-film piezoresistive pressure measuring system. Infrapatellar tissue pressure was analyzed using a closed sensor-cell. Three different patella braces were fitted to the knee cadavers and their influence on the kinematic and kinetic biomechanical parameters were evaluated and compared to the physiologic situation. Patellar bracing resulted in a significant (p = 0.05) proximalization of the patella up to 3 mm. Depending on the type of brace used, a decrease in the infrapatellar fat pad pressure was found and the patellofemoral contact area was decreased significantly (p = 0.05) between 60 degrees of knee flexion and full extension (maximum 22%). Patella bracing significantly (p = 0.05) reduced the patellofemoral contact pressure an average of 10%, as well as the peak contact pressure which occurred. Patellar bracing significantly influences patella biomechanics in a reduction of the patellofemoral contact area and contact pressure as well as a decrease in the infrapatellar tissue pressure. The application of infrapatellar straps is suggested for the treatment and prevention of anterior knee pain, especially in high level sports.

Anterior knee pain and thigh muscle strength after intramedullary nailing of a tibial shaft fracture: an 8-year follow-up of 28 consecutive cases

OBJECTIVES

Chronic anterior knee pain is a common complication after intramedullary nailing of a tibial shaft fracture. The source of pain is often not known, although it correlates with a simultaneous decrease in thigh muscle strength. No long-term follow-up study has assessed whether weakness of the thigh muscles is associated with anterior knee pain after the procedure in question.

DESIGN

Prospective study.

SETTING

University Hospital of Tampere, University of Tampere.

PATIENTS

The muscular performance of 40 consecutive patients with a nailed tibial shaft fracture was tested isokinetically in a follow-up examination an average of 3.2 +/- 0.4 (SD) years after the initial surgery. An 8-year follow-up was possible in 28 of these cases.

MAIN OUTCOME MEASUREMENTS

Isokinetic muscle strength measurements were made in 28 patients at an average 8.1 +/- 0.3 (SD) years after nail insertion and an average 6.6 +/- 0.3 (SD) years after nail extraction. All nails were extracted at an average 1.6 +/- 0.2 years after the nailing.

RESULTS

: Seven patients were painless initially and still were at final follow-up (never pain, or NP). In 13 patients, the previous symptom of anterior knee pain was no longer present at final follow-up [pain, no pain (PNP)], and the remaining 8 had anterior knee pain initially and at final follow-up [always pain group (AP)]. With reference to the hamstring muscles, the mean peak torque difference between the injured and uninjured limb was -2.2% +/- 12% in the NP group, 1.6% +/- 15% in the PNP group, and 10.3% +/- 30% in the AP group at a speed of 60 degrees/second (Kruskal-Wallis test; chi(2) = 1.0; P = 0.593). At a speed of 180 degrees/second, the corresponding differences were -2.9% +/- 23% and 7.0% +/- 19% and 4.4% +/- 16% (Kruskal-Wallis test; chi = 1.7; P = 0.429). With reference to the quadriceps muscles, the mean peak torque difference was -2.8% +/- 9% in the NP group, 5.9% +/- 15% in the PNP group, and -13.0% +/- 16% in the AP group at a speed of 60 degrees/second (Kruskal-Wallis test; chi(2) = 7.9; P = 0.019). At 180 degrees/second, the corresponding differences were -9.4% +/- 13% and 4.9% +/- 16% and -1.9% +/- 9%, respectively (Kruskal-Wallis test; chi(2) = 4.8; P = 0.092).

CONCLUSION

Based on this prospective long-term follow-up study, it appears that the anterior knee pain symptoms that are present after intramedullary nailing of a tibial shaft fracture disappear in a number of patients 3 to 8 years after surgery. Quadriceps, but not hamstring weakness, and lower functional knee scores are associated with anterior knee pain at 8 years.

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.

Infrapatellar fat pad pressure and volume changes of the anterior compartment during knee motion: possible clinical consequences to the anterior knee pain syndrome

This biomechanical study was performed to measure tissue pressure in the infrapatellar fat pad and the volume changes of the anterior knee compartment during knee flexion-extension motion. Knee motion from 120 degrees of flexion to full extension was simulated on ten fresh frozen human knee specimens (six from males, four from females, average age 44 years) using a hydraulic kinematic simulator (30, 40, and 50 Nm extension moment). Infrapatellar tissue pressure was measured using a closed cell sensor. Infrapatellar volume change in the anterior knee compartment was evaluated subsequent to removal of the fat pad using a water-filled bladder. We found a significant increase of the infrapatellar tissue pressure during knee flexion, at flexion angles of <20 degrees and >100 degrees . The average tissue pressure ranged from 343 (+/-223) mbar at 0 degrees to 60 (+/-64) mbar at 60 degrees of flexion. The smallest volume in the anterior knee compartment was measured at full extension and 120 degrees of flexion, whereas the maximum volume was observed at 50 degrees of flexion. In conclusion, the data suggest a biomechanical function of the infrapatellar fat pad at flexion angles of <20 degrees and >100 degrees , which suggests a role of the infrapatellar fat pad in stabilizing the patella in the extremes of knee motion.

Exercise Prescription and Patellofemoral Pain: Evidence for Rehabilitation

Objective:

To provide evidence regarding the therapeutic effects of exercise on subjects with patellofemoral-pain syndrome (PFPS).

Data Sources:

Evidence was compiled with data located using the Medline, CINAHL, and SPORTDiscus databases from 1985 to 2004 using the key wordspatellofemoral pain syndrome, exercise, rehabilitation,andstrength.

Study Selection:

The literature review examined intervention studies evaluating the effectiveness of exercise in subjects specif-cally diagnosed with PFPS. Articles were selected based on clinical relevance to PFPS rehabilitation that required an intervention of a minimum of 4 weeks.

Data Synthesis:

The review supports using exercise as the primary treatment for PFPS.

Conclusions:

Evidence exists regarding the use of isometric, isotonic, isokinetic, and closed kinetic chain exercise. Although clinicians have advocated the use of biofeedback and patella taping, there is limited evidence regarding the efficacy of these interventions on subjects diagnosed with PFPS.

Biomechanical and kinematic influences of a total infrapatellar fat pad resection on the knee

BACKGROUND

This biomechanical study was performed to evaluate the consequences of total infrapatellar fat pad resection on knee kinematics and patellar contact pressure.

HYPOTHESIS

Resection of the infrapatellar fat pad produces significant changes in knee kinematics and patellar contact pressure.

STUDY DESIGN

Biomechanical cadaveric study.

METHODS

Isokinetic knee extension was simulated on 10 human knee cadaveric specimens (6 men, 4 women; mean age at death, 44 years). Joint kinematics were evaluated by an ultrasound-based 3D motion analysis system, and retro-patellar contact pressure was measured using an electronic pressure-sensitive film. All data were taken before and after resection of the infrapatellar fat pad and statistically analyzed.

RESULTS

A total resection of the infrapatellar fat pad resulted in a significant decrease of the tibial external rotation relative to the femur between 63 degrees of flexion and full knee extension (maximum: 3 degrees rotation difference at 0 degrees knee flexion, P = .011), combined with a significant medial translation of the patella between 29 degrees and 69 degrees of knee flexion (range, 0.9-1.3 mm, P = .017-.028). Retro-patellar contact pressure was significantly reduced (from 20% to 25%, P = .008-.021) at all flexion angles.

CONCLUSION

A resection of the infrapatellar fat influences patellar biomechanics and knee kinematics.

CLINICAL RELEVANCE

The infrapatellar fat pad may have a biomechanical function and may play a role in anterior knee pain syndrome.

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.

Systematic review of the quality of randomized controlled trials for patellofemoral pain syndrome

STUDY DESIGN

Systematic review of the literature.

OBJECTIVES

To develop a grading scale to judge the quality of randomized clinical trials (RCTs) and conduct a systematic review of the published RCTs that assess nonoperative treatments for patellofemoral pain syndrome (PFPS).

BACKGROUND

Systematic reviews of the quality and usefulness of clinical trials allow for efficient synthesis and dissemination of the literature, which should facilitate clinicians' efforts to incorporate principles of evidence-based practice in the clinical decision-making process.

METHODS AND MEASURES

Using a scale based on criteria in the Cochrane Collaboration Handbook, we sought to critically appraise the methodology used in RCTs related to the nonoperative management of PFPS, synthesize and interpret our results, and report our findings in a user-friendly fashion. A scale to assess the methodological quality of trials was designed and pilot tested for its content and reliability. Published RCTs identified during a literature search were then selected and rated by 6 raters. We used predefined cutoff scores to identify specific weaknesses in the clinical research process that need to be improved in future clinical trials.

RESULTS

The quality scale we developed was demonstrated to be sufficiently reliable to warrant interpretation of the reviewers' findings. The percentage of trials that met a minimum level of quality for each specific criterion ranged from a low of 25% for the adequacy of the description of the randomization procedure to a high of 95% for the description and standardization of the intervention.

CONCLUSIONS

Based on the results of trials exhibiting a sufficient level of quality, treatments that were effective in decreasing pain and improving function in patients with PFPS were acupuncture, quadriceps strengthening, the use of a resistive brace, and the combination of exercises with patellar taping and biofeedback. The use of soft foot orthotics in patients with excessive foot pronation appeared useful in decreasing pain. In addition, at a short-term follow-up, patients who received exercise programs were discharged earlier from physical therapy. Unfortunately, most RCTs reviewed contained qualitative flaws that bring the validity of the results into question, thus diminishing the ability to generalize the results to clinical practice. These flaws were primarily in the areas of randomization procedures, duration of follow-up, control of cointerventions, assurance of blinding, accountability and proper analysis of dropouts, number of subjects, and the relevance of outcomes. Also, given the limited number of high-quality clinical trials, recommendations about supporting or refuting specific treatment approaches may be premature and can only be made with caution.

Exercise therapy for patellofemoral pain syndrome

BACKGROUND

Patellofemoral pain syndrome (PFPS) is a common problem among adolescents and young adults, characterised by retropatellar pain (behind the kneecap) or peripatellar pain (around the kneecap) when ascending or descending stairs, squatting or sitting with flexed knees. Etiology, structures causing the pain and treatment methods are all debated in literature, but consensus has not been reached so far. Exercise therapy to strengthen the quadriceps is often prescribed, though its efficacy is still debated.

OBJECTIVES

This review aims to summarise the evidence of effectiveness of exercise therapy in reducing anterior knee pain and improving knee function in patients with PFPS.

SEARCH STRATEGY

We searched the Cochrane Musculoskeletal Injuries Group and Cochrane Rehabilitation and Related Therapies Field specialised registers, the Cochrane Controlled Trials Register, PEDro - The Physiotherapy Evidence Database, MEDLINE, EMBASE, CINAHL, up till December 2001 for controlled trials (randomised or not) comparing exercise therapy with control groups, or comparing different types of exercise therapy.

SELECTION CRITERIA

Only trials focusing on exercise therapy in patients with PFPS were considered. Trials in patients with other diagnoses such as tendinitis, Osgood Schlatter syndrome, bursitis, traumatic injuries, osteoarthritis, plica syndrome, Sinding-Larssen-Johansson syndrome and patellar luxations were excluded.

DATA COLLECTION AND ANALYSIS

From 750 publications 12 trials were selected. All included trials studied quadriceps strengthening exercises. Outcome assessments for knee pain and knee function in daily life were used in a best evidence synthesis to summarise evidence for effectiveness.

MAIN RESULTS

One high and two low quality studies used a control group not receiving exercise therapy. Significantly greater pain reduction in the exercise groups was found in one high and one low quality study, though at different time points. Only one low quality study reported significantly greater functional improvement with exercise. Five studies compared exercise therapies that could be designated closed kinetic chain exercise (foot in contact with a surface) versus open kinetic chain exercise (foot not in contact with a surface). Two of these studies were of high quality, but no significant differences in improvement of function or reduction of pain were apparent between the types of exercise in any of the studies. The remaining four studies, all of which were of low quality, focused on other treatment comparisons.

REVIEWER'S CONCLUSIONS

The evidence that exercise therapy is more effective in treating PFPS than no exercise was limited with respect to pain reduction, and conflicting with respect to functional improvement. There is strong evidence that open and closed kinetic chain exercise are equally effective. Further research to substantiate the efficacy of exercise treatment compared to a non-exercising control group is needed, and thorough consideration should be given to methodological aspects of study design and reporting.

Which factors predict outcome in the treatment program of anterior knee pain?

The goal of this prospective study was to determine the outcome-predictive role of various parameters in the nonoperative treatment of chronic anterior knee pain patients. Thirty patients followed a five-week treatment program, which consisted out of only closed kinetic chain exercises. Prior to this treatment all subjects were evaluated on muscular characteristics, subjective symptoms, weight, sex, duration of symptoms and functional performance. A multiple stepwise regression analysis revealed that the reflex response time of m. vastus medialis obliquus (VMO) (P=0.041; 0.026), and the duration of symptoms (P=0.019; 0.045) were the only two parameters which were significantly associated with the outcome (evaluated by the Kujala score) at five weeks, and at three months. The shorter the duration of symptoms, or the faster the reflex response time of VMO prior to the treatment, the better the outcome after a closed kinetic chain exercise program. The statistical significance of these parameters in this study may be seen as an indication of the importance of these variables as predictors of the outcome of a closed kinetic chain strengthening program. Using this information, it seems clinically important to begin the treatment program before the anterior knee pain becomes more chronic and treatment results become less good.