The effects of quadriceps strengthening on pain, function, and patellofemoral joint contact area in persons with patellofemoral pain

Effects of high frequency strengthening on pain sensitivity and function in female runners with chronic patellofemoral pain

OBJECTIVE

To investigate the effects of a high frequency strengthening program on function, pain, and pain sensitization in female runners with chronic patellofemoral pain (PFP).

DESIGN

Cross-sectional study.

SETTING

University laboratory.

PARTICIPANTS

Thirty female runners (mean age 32 ± 8.1 years) with chronic PFP completed an 8-week home strengthening program.

MAIN OUTCOME MEASURES

Variables assessed at baseline, 8-weeks, and 12 weeks included single leg step down test (SLSD), pain, Anterior Knee Pain Scale (AKPS), University of Wisconsin Running Injury and Recovery Index (UWRI), and quantitative sensory testing.

RESULTS

There was large and statistically significant improvement at 8 and 12 weeks for average knee pain (ηp2 = 0.334, p < 0.001), worst knee pain (ηp2 = 0.351, p < 0.001), SLSD (ηp2 = 0.161, p = 0.001), AKPS (ηp2 = 0.463, p < 0.001), and UWRI (ηp2 = 0.366, p < 0.001). A medium to large effect and statistically significant improvement in pressure pain threshold testing was found for all local and remote structures (ηp2 range, 0.110 to 0.293, range p < 0.001 to p = 0.009) at 8 and 12 weeks.

CONCLUSIONS

There was a significant decrease in local and remote hyperalgesia via mechanical and thermal pain sensitivity testing in female runners with chronic PFP. There was a large effect and significant improvement in self-reported pain and function.

The effect of high-intensity laser therapy on pain and lower extremity function in patellofemoral pain syndrome: a single-blind randomized controlled trial

Patellofemoral pain syndrome (PFPS) is a set of symptoms that negatively affect the daily life activities of the individual, leading to functional disability and significant loss of labor, especially in young adults. PFPS is usually due to weakness of the vastus medialis obliquus (VMO) resulting in abnormal patellar tracking and pain. Our study aims to compare the efficacy of high-intensity laser therapy (HILT) on pain and lower extremity function in the treatment of PFPS with different electrophysical agents (EPAs). The study was designed as a single-blind randomized controlled trial. Forty-five people with PFPS (aged 25-45 years) were included in the study. The patients were randomly divided into three groups and a total of ten sessions of treatment were administered to all three groups for 2 weeks, 5 days a week. High-intensity laser (HILT) and exercise program were applied to group 1. Ultrasound (US), transcutaneous electrical nerve stimulation (TENS), and exercise program were applied to group 2. In group 3, US, interferential current (IFC), and exercise program were applied. Both groups underwent three evaluations: pre-treatment, post-treatment, and 12 weeks after treatment. Outcome measures included the visual analog scale for pain severity (VAS), knee flexion range of motion (FROM), Q angle, pain threshold, muscle strength of quadriceps and hamstring, Kujala patellofemoral scoring, lower extremity functional scale (LEFS), and Timed Up and Go Test (TUG). The ANOVA was used for comparing the data of the groups, and two-way repeated measure ANOVA was used to compare at the pre-post and post-intervention 3rd month. The LSD and Bonferroni post hoc tests were also used to identify the between-group differences. Groups 2 and 3 were statistically effective in pain and functionality (p < 0.05). Group 1 was found to be statistically more effective than other groups in reducing pain (95% confidence interval (CI), 0.000/0.000; p = 0.000), increasing knee flexion angle (95% CI, 127.524/135.809; p = 0.000), and increasing lower extremity function (95% CI, 75.970/79.362; p = 0.000). This study indicated that high-intensity laser therapy was found to be a more effective method in the treatment of patellofemoral pain syndrome after 3 months of follow-up compared to US-TENS combination and US-interferential current combination treatments. Also, HILT can be used as an effective method in combination with an appropriate exercise program including vastus medialis strengthening to reduce pain and increase functionality in the patients with PFPS.

Strength Training Is Associated With Less Knee Osteoarthritis: Data From the Osteoarthritis Initiative

OBJECTIVE

We aimed to evaluate the relationship of a history of strength training with symptomatic and structural outcomes of knee osteoarthritis (OA).

METHODS

This study was a retrospective, cross-sectional study within the Osteoarthritis Initiative (OAI), a multicenter prospective longitudinal observational study. Data were collected at four OAI clinical sites: Memorial Hospital of Rhode Island, the Ohio State University, the University of Pittsburgh, and the University of Maryland/Johns Hopkins. The study included 2,607 participants with complete data on strength training, knee pain, and radiographic evidence of knee OA (male, 44.2%; mean ± SD age 64.3 ± 9.0 years; mean ± SD body mass index 28.5 ± 4.9 kg/m2 ). We used a self-administered questionnaire at the 96-month OAI visit to evaluate the exposure of strength training participation during four time periods throughout a participant's lifetime (ages 12-18, 19-34, 35-49, and ≥50 years old). The outcomes (dependent variables) were radiographic OA (ROA), symptomatic radiographic OA (SOA), and frequent knee pain.

RESULTS

The fully adjusted odds ratios (95% confidence interval) for frequent knee pain, ROA, and SOA among those who participated in strength training any time in their lives were 0.82 (0.68-0.97), 0.83 (0.70-0.99), and 0.77 (0.63-0.94), respectively. Findings were similar when looking at the specific age ranges.

CONCLUSION

Strength training is beneficial for future knee health, counteracting long-held assumptions that strength training has adverse effects.

Home-based exercise program and Health education in patients with patellofemoral pain: a randomized controlled trial

BACKGROUND

Patellofemoral pain (PFP) is one of the most common disorders of the knee joint. Home-based exercise is an effective intervention to achieve self-management for chronic diseases. This study evaluated the effects of home-based exercise and health education in patients with PFP.

METHODS

Patients who had PFP were randomly allocated to an intervention group (IG) or control group (CG). Patients in the IG received a 6-week tailored home-based exercise program with health education via remote support, while patients in the CG group only received health education. Clinical outcomes were compared using the Anterior Knee Pain Scale (AKPS) to measure function and the Visual Analog Scale (VAS) to measure "worst pain" and "pain with daily activity". Muscle strength was measured according to the peak torque of the knee muscles using an isokinetic system.

RESULTS

Among a total of 112 participants screened for eligibility, 38 were randomized and analyzed, including 19 participants in the intervention group and 19 participants in the control group. There were no significant differences in baseline characteristics between the groups. At 6-week follow-up, the intervention group showed a greater worst pain reduction (between-group difference, -19.3 [95%CI, -23.2 to -15.5]; P < 0.01) and pain with daily activity (between-group difference, -22.9 [95%CI, -28.3 to -17.4]; P < 0.01) than the control group. Similarly, the intervention group had better improvements in AKPS (between-group difference, 9.0 [95%CI, 4.1 to 13.9]; P < 0.01) and knee extensor strength (between-group difference, 20.1 [95%CI, 14.5 to 25.8]; P < 0.01), compared to the control group. No adverse events were reported.

CONCLUSION

Home-based exercise and health education resulted in less pain, better function, and higher knee muscle strength compared with no exercise in patients with PFP. A large randomized controlled trial with long-term follow-up is required to confirm these findings.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2200056224 ( https://www.chictr.org.cn/showproj.aspx?proj=135506 ). Registered on February 1, 2022.

Sex Differences in Knee Extensor Neuromuscular Function in Individuals With and Without Patellofemoral Pain

BACKGROUND

Impaired knee extensor neuromuscular function has been frequently observed in individuals with patellofemoral pain (PFP); however, few researchers have aimed to understand the influence of sex on knee extensor neuromuscular function in this pathological population. The authors aimed to determine whether there are differences in knee extensor neuromuscular function between sexes in individuals with and without PFP.

HYPOTHESIS

Women with PFP would exhibit greater deficits in knee extensor neuromuscular function than men with PFP, compared with sex-matched individuals without PFP.

STUDY DESIGN

Cross-sectional, case-control study.

LEVEL OF EVIDENCE

Level 4.

METHODS

A total of 110 individuals were classified into 4 groups: women with PFP (n = 25); men with PFP (n = 30); women without PFP (n = 25); and men without PFP (n = 30). Knee extensor strength (isometric peak torque [PT]), activation (central activation ratio), early, late, and total phase rate of torque development (RTD0-100, RTD100-200, and RTD20-80%), and endurance (isokinetic average PT) were assessed using an isokinetic dynamometer. Group differences were assessed using a 2-way multivariate analysis of variance (sex by PFP).

RESULTS

Both women and men with PFP exhibited lower knee extensor strength, activation, early, late, and total phase RTD, and endurance versus sex-matched individuals without PFP (P < 0.05 for all comparisons). Women with PFP exhibited lower early phase (7.91 ± 2.02 versus 9.78 ± 2.43 N·m/s/kg; P < 0.01; Cohen d = 0.83), late phase (5.34 ± 1.02 versus 7.28±2.28 N·m/s/kg; P < 0.01; Cohen d = 1.37), and total phase (7.40 ± 2.57 versus 8.72 ± 2.57 N·m/s/kg; P = 0.03; Cohen d = 0.51) RTD than men with PFP.

CONCLUSION

Compared with sex-matched pain-free individuals, women with PFP displayed lower RTD than men with PFP. Clinicians should note that among individuals with PFP, women are more likely to experience a greater impairment in their knee extensor torque-generating capacity than men.

CLINICAL RELEVANCE

Additional treatment strategies that effectively improve the ability to rapidly generate torque should be developed and implemented, especially when treating women with PFP.

Lower extremity muscle volume in females with patellofemoral pain and its relationships to hip and knee torque: A cross-sectional study

OBJECTIVES

Compare lower extremity muscle volume in females with patellofemoral pain (PFP) to a cohort of pain-free females and investigate the relationship between thigh and hip muscle volume and torque.

DESIGN

Cross-sectional.

PARTICIPANTS

Twenty-one females, 13 with PFP and 8 pain-free controls.

MAIN OUTCOME MEASURES

We quantified normalized lower extremity muscle volume (cm3/kg*m) via magnetic resonance imaging and isometric hip and thigh torque (Nm/kg) via a multimodal dynamometer.

RESULTS

Versus pain-free individuals, females with PFP had smaller muscle volume of the anterior hip (P < 0.019; d = 0.97-2.42), deep external rotators (P < 0.006; d = 1.0-3.93), hamstrings (P < 0.009; d = 1.09-2.12), rectus femoris (P < 0.001; d = 1.79), and vastus intermedius (P < 0.001; d = 1.88). There was no difference in muscle volume of the gluteus maximus (P = 0.311; d = 0.22), gluteus medius (P = 0.087; d = 0.87), vastus lateralis (P = 0.22; d = 0.39), and vastus medialis (P = 0.47; d = 0.04). Gluteus maximus volume was moderately correlated to hip abduction torque (r = 0.60; P = 0.03). Vasti muscles and semitendinosus volume were moderately correlated to knee extension (r = 0.57-0.69; P < 0.05) and flexion (r = 0.66; P = 0.01) torque, respectively.

CONCLUSION

Females with PFP present with lesser thigh and hip muscle volumes, with variability in volumetric profiles across participants. Lower extremity knee extension and hip abduction strength are moderately associated with the vasti and gluteus maximus muscle volume, respectively.

ADAPTations to low load blood flow restriction exercise versus conventional heavier load resistance exercise in UK military personnel with persistent knee pain: protocol for the ADAPT study, a multi-centre randomized controlled trial

BACKGROUND

Muscle atrophy, muscle weakness and localised pain are commonly reported following musculoskeletal injury (MSKI). To mitigate this risk and prepare individuals to return to sport or physically demanding occupations, resistance training (RT) is considered a vital component of rehabilitation. However, to elicit adaptations in muscle strength, exercise guidelines recommend lifting loads ≥ 70% of an individual's one repetition maximum (1-RM). Unfortunately, individuals with persistent knee pain are often unable to tolerate such high loads and this may negatively impact the duration and extent of their recovery. Low load blood flow restriction (LL-BFR) is an alternative RT technique that has demonstrated improvements in muscle strength, hypertrophy, and pain in the absence of high mechanical loading. However, the effectiveness of high-frequency LL-BFR in a residential rehabilitation environment remains unclear. This study will compare the efficacy of high frequency LL-BFR to 'conventional' heavier load resistance training (HL-RT) on measures of physical function and pain in adults with persistent knee pain.

METHODS

This is a multicentre randomised controlled trial (RCT) of 150 UK service personnel (aged 18-55) admitted for a 3-week residential rehabilitation course with persistent knee pain. Participants will be randomised to receive: a) LL-BFR delivered twice daily at 20% 1-RM or b) HL-RT three-times per week at 70% 1-RM. Outcomes will be recorded at baseline (T1), course discharge (T2) and at three-months following course (T3). The primary outcome will be the lower extremity functional scale (LEFS) at T2. Secondary outcomes will include patient reported perceptions of pain, physical and occupational function and objective measures of muscle strength and neuromuscular performance. Additional biomechanical and physiological mechanisms underpinning both RT interventions will also be investigated as part of a nested mechanistic study.

DISCUSSION

LL-BFR is a rehabilitation modality that has the potential to induce positive clinical adaptations in the absence of high mechanical loads and therefore could be considered a treatment option for patients suffering significant functional deficits who are unable to tolerate heavy load RT. Consequently, results from this study will have a direct clinical application to healthcare service providers and patients involved in the rehabilitation of physically active adults suffering MSKI.

TRIAL REGISTRATION

ClinicalTrials.org reference number, NCT05719922.

Knee Loading With Blood Flow Restriction Can Enhance Recovery After Total Knee Arthroplasty

Total knee arthroplasty (TKA) is one of the most performed operations in the world, especially in the elderly. Aging has a significant effect on joint cartilage, muscle strength, and muscle mass. Following a TKA, despite the significant reduction of symptoms and the improvement in mobility, muscle strength and muscle mass recovery remains a significant challenge. Restrictions that arise from the surgical procedure include joint loading, functional activities, and range of motion, along with limitations related to the age of the individual and their previous loading history, these are the significant restrictions, at least in the early stages of rehabilitation. Evidence indicates that blood flow restriction (BFR) training has significant potential to enhance recovery via implementation of low-load or low-intensity exercise. While respecting the indications and contraindications related to BFR application, the optimization of metabolic stress seems to offer a bridging therapy to heavy load while reducing pain and inflammation. Thus, the combination of BFR and low loads may improve muscular recovery (strength and mass), and aerobic training protocols appear to show significant enhancement of multiple cardiopulmonary parameters. Mounting evidence, direct and indirect, indicate that BFR training may have the potential to benefit the pre-operative and post-operative TKA rehabilitation phases and enhance functional recovery and physical abilities in the elderly.

Empirical joint contact mechanics: A comprehensive review

Empirical joint contact mechanics measurement (EJCM; e.g. contact area or force, surface velocities) enables critical investigations of the relationship between changing joint mechanics and the impact on surface-to-surface interactions. In orthopedic biomechanics, understanding the changes to cartilage contact mechanics following joint pathology or aging is critical due to its suggested role in the increased risk of osteoarthritis (OA), which might be due to changed kinematics and kinetics that alter the contact patterns within a joint. This article reviews and discusses EJCM approaches that have been applied to articulating joints such that readers across different disciplines will be informed of the various measurement and analysis techniques used in this field. The approaches reviewed include classical measurement approaches (radiographic and sectioning, dye staining, casting, surface proximity, and pressure measurement), stereophotogrammetry/motion analysis, computed tomography (CT), magnetic resonance imaging (MRI), and high-speed videoradiography. Perspectives on approaches to advance this field of EJCM are provided, including the value of considering relative velocity in joints, tractional stress, quantification of joint contact area shape, consideration of normalization techniques, net response (superposition) of multiple input variables, and establishing linkages to regional cartilage health status. EJCM measures continue to provide insights to advance our understanding of cartilage health and degeneration and provide avenues to assess the efficacy and guide future directions of developing interventions (e.g. surgical, biological, rehabilitative) to optimize joint's health and function long term.

Effect of hip abductors and lateral rotators' muscle strengthening on pain and functional outcome in adult patients with patellofemoral pain: A systematic review and meta-analysis

BACKGROUND

Even though literature indicates presence of weak hip abductors and lateral rotators' in Patellofemoral Pain (PFP), studies evaluating the effect of hip abductors and lateral rotators strengthening to improve knee function and quality of life in PFP are limited.

OBJECTIVE

This study systematically reviews and meta-analyzes the best evidence on the therapeutic value of strengthening hip abductors and lateral rotators muscles for treating PFP with a presumptive hypothesis that strengthening hip muscles stabilizes the patellofemoral joint, relieves pain, and enhances knee functions.

METHOD

Medline, EMBASE, CINAHL, PEDro and PubMed Central databases were searched between January 1994 and September 2019 using the PICOS tool. The methodological quality of the selected studies were appraised individually using the 20-item McMaster Critical Review Form for Quantitative Studies. Supplemental quality appraisal of randomized controlled clinical trials performed using the Cochrane Collaboration's 'Risk of bias' quality criteria. Data on patient population demographics, interventions, duration of intervention, and outcome measures were extracted and summarized in evidence tables and descriptive analysis. Meta-analyses under both fixed and random-effects models determined pooled effects size from appropriate RCTs.

RESULTS

All fourteen studies demonstrated that hip muscle strengthening improved pain and knee function. All RCTs, except one, demonstrated that hip muscle strengthening is superior to quadriceps strengthening. Of the five RCTs assessing the additional effect of hip-quad versus quadriceps strengthening, four suggested that hip-quad strengthening is superior to standard quadriceps strengthening alone to improve PFP and knee function.

CONCLUSION

In adult patients with PFP, strengthening hip abductors and lateral rotators' have beneficial therapeutic effects than the conventional quadriceps exercises in improving knee pain and function both in the short- and long term. However, the present review data can be used to develop a standardized hip-quad protocol in the future.

Quadriceps strengthening by the Kaatsu Training method in women with patellofemoral pain

ABSTRACT This is a cross-sectional, comparative, and randomized study aimed to evaluate the effects of the partial vascular occlusion technique (Kaatsu Training) associated with low load exercises in the muscle strengthening of quadriceps in women with patellofemoral pain. We evaluated 18 women with patellofemoral pain, aged from 18 to 35 years, allocated into two groups. The experimental group performed the strengthening with blood flow reduction with the aid of a sphygmomanometer, associated with low load (≅20% RM). Whereas the control group performed exercises with the same load, but without blood flow reduction. The treatment was performed three times a week for six weeks, totaling 18 sessions. We used the numerical pain rating scale (NPRS) and the anterior knee pain scale (AKPS) questionnaire for evaluation; we evaluated the muscle strength of knee extensors by the digital dynamometer. The results showed that the partial vascular occlusion technique significantly improved the values of quadriceps strength gain in the right, 6.22kg (p=0.03) and left limb, 6.98kg (p=0.04), in women with patellofemoral pain. Therefore, training with partial vascular occlusion can be useful for strengthening of the knee extensor musculature in women with patellofemoral pain who, because of the pain, have low tolerance to high load exercises for muscle strengthening. An effective, safe and cost-effective technique, which does not require an investment in a leg extension machine, since, with a cuff, low load exercises can offer significant results.

Fortalecimento do quadríceps através do método Kaatsu Training em mulheres com dor femoropatelar

RESUMO Este é um estudo transversal, comparativo e randomizado, cujo objetivo foi avaliar os efeitos da técnica de oclusão vascular parcial (Kaatsu Training) associada a exercícios de baixa carga no fortalecimento muscular de quadríceps em mulheres com dor femoropatelar. Foram avaliadas 18 mulheres com dor femoropatelar, com idade entre 18 e 35 anos, que foram alocadas em dois grupos. O grupo experimental realizou fortalecimento com redução do fluxo sanguíneo por meio de um esfigmomanômetro, associado com baixa carga (≅20% RM). Enquanto o grupo-controle realizou exercícios com a mesma carga, porém sem redução do fluxo sanguíneo. O tratamento foi realizado três vezes na semana, em um período de seis semanas, totalizando 18 sessões. Para avaliação foram utilizadas a escala numérica de avaliação da dor (NPRS) e o questionário anterior knee pain scale (AKPS); a força muscular de extensores do joelho foi avaliada através do dinamômetro digital. Os resultados mostraram que a técnica de oclusão vascular parcial provocou melhorias significativas nos valores de ganho de força do quadríceps no membro direito, 6,22kg (p=0,03), e esquerdo, 6,98kg (p=0,04), em mulheres com dor femoropatelar. Portanto, treinamento com oclusão vascular parcial pode ser uma alternativa útil para ganho de força da musculatura extensora do joelho em mulheres com dor femoropatelar que, devido à dor, tenham baixa tolerância a exercícios de alta carga para fortalecimento muscular, sendo uma técnica eficaz, segura e com boa relação de custo-benefício, não necessitando a compra de uma cadeira extensora, uma vez que utilizando um manguito é possível obter resultados significativos associados a exercícios de baixa carga.

The Effect of Self-Myofascial Release on the Pennation Angle of the Vastus Medialis Oblique and the Vastus Lateralis in Athletic Male Individuals: An Ultrasound Investigation

Background

Maintenance of patellar stability requires a balance between the vastus medialis oblique (VMO) and the vastus lateralis (VL). The imbalance between these muscles is thought to be implicated in the etiology of patellofemoral pain (PFP). Where there is hypertrophy of the VL in PFP patients, self-myofascial release (SMR) may be utilized for its management. However, there is no current evidence regarding SMR and its effects on VMO and VL architecture. The aim of this study, therefore, was to use ultrasound to gain further understanding of the effects of a program of SMR on the fiber angles of the VMO and VL.

Hypothesis

There will be a significant decrease in the pennation angles of the VMO and VL after seven weeks of SMR using a foam roller.

Study Design

Cohort Study.

Methods

Twenty-five young, athletic, male participants were recruited to use a foam roller, along the full length of both anterior thighs, three times weekly, on three separate days, for seven weeks. Ultrasound was used to determine the initial and final VMO and VL pennation angles on both limbs. One eligible participant was chosen as an intra-rater control and did not partake in the SMR regimen.

Results

There was a statistically significant (p < 0.001) decrease in the pennation angles of the VMO and VL after the SMR regime. Mean combined right and left VL angle change was -6.65° (-18% mean change) and the mean combined right and left VMO angle change was -7.65° (-11.5% mean change). A weak negative correlation was found between initial VMO fiber angle and the angle change (Rsquared = -0.21), as well as moderate negative correlation for the VL (Rsquared = -0.51).

Conclusion

A program of SMR on the anterior thighs of young, asymptomatic males resulted in changes to the fiber angles of both the VMO and VL. There was a significant decrease in pennation angle after seven weeks of SMR using a foam roller.

Optimizing Rehabilitation and Return to Sport in Athletes With Anterior Knee Pain Using a Biomechanical Perspective

Anterior knee pain represents one of the most common athletic knee conditions and arguably also one of the most complex. The patellofemoral joint is at the center of several forces, and alterations in any of these force vectors due to muscular imbalance, soft-tissue tightness or laxity, and altered functional movement patterns can all combine to create a painful anterior knee. While typically anterior knee pain is not a surgical entity, the orthopaedic surgeon with an understanding of these biomechanical intricacies is best positioned to provide comprehensive evidence-based care for the patient with anterior knee pain.

Level of Evidence

V, expert opinion.

Management of Chondral Defects Associated with Patella Instability

Cartilage defects of the patellofemoral joint are commonly found in association with patellar instability owing to abnormal biomechanics. Strategies to address chondral defects of the patellofemoral joint secondary to instability should first address causes of recurrent instability. Most patellofemoral chondral defects associated with instability are less than 2 cm2 and do not generally require intervention beyond chondroplasty. Larger defects of the patella and/or the trochlea can be repaired with osteochondral or surface cartilage repair.

Optimal parameters of blood flow restriction and resistance training on quadriceps strength and cross-sectional area and pain in knee osteoarthritis

BACKGROUND: Knee osteoarthritis (KOA) is one of the most common chronic diseases impacting millions of elderly people. OBJECTIVES: The study compared the effects of two intensities of partial blood flow restriction (BFR) with low-intensity resistance training on quadriceps strength and cross-sectional area (CSA), and pain in people with knee osteoarthritis (PwKOA). METHODS: Thirty-five PwKOA, aged 50–65, participated. Quadriceps CSA was measured by ultrasonography, quadriceps strength – by isokinetic dynamometry and pain by VAS. These outcome variables were obtained at the beginning of the study and re-evaluated eight weeks after the intervention. RESULTS: An interaction effect was present for quadriceps CSA (P= 0.042) and quadriceps strength (P= 0.006), showing that using 70% of total occlusion pressure with 30% 1RM had a more significant effect. Knee pain improved significantly through the main effect of BFR (P< 0.001), and low-intensity resistance training (P= 0.011). Pain improved more at 70% of total occlusion pressure, with 30% of 1RM (2.5 ± 1.06) than 50% total occlusion pressure with 10% of 1RM (5.77 ± 1.46). CONCLUSION: A combination of 70% of total occlusion pressure with 30% 1RM could be beneficial in PwKOA in improving pain, and increasing the quadriceps strength. The changes in the quadriceps strength could be a predictor for knee pain.

Effects of Static and Dynamic Stretching With Strengthening Exercises in Patients With Patellofemoral Pain Who Have Inflexible Hamstrings: A Randomized Controlled Trial

BACKGROUND

Patellofemoral pain (PFP) syndrome is closely associated with muscle tightness. However, studies regarding the effects of stretching exercises on PFP patients with inflexible hamstrings are scarce. The aim of the study was to compare the effects between static and dynamic hamstring stretching in patients with PFP who have inflexible hamstrings.

HYPOTHESIS

Compared with static hamstring stretching, dynamic hamstring stretching will improve the parameters of hamstring flexibility, knee muscle strength, muscle activation time, and clinical outcomes in this patient population.

STUDY DESIGN

Prospective randomized controlled trial.

LEVEL OF EVIDENCE

Level 2.

METHODS

A total of 46 patients (25, static stretching; 21, dynamic stretching) participated. Hamstring flexibility was assessed according to the popliteal angle during active knee extension. Muscle strength and muscle activation time were measured using an isokinetic device. Clinical outcomes were evaluated using the visual analog scale (VAS) for pain and the anterior knee pain scale (AKPS).

RESULTS

There were no differences in hamstring flexibility and knee muscle strength of the affected knees between the groups (P > 0.05). Significantly improved muscle activation time and clinical outcomes of the affected knees were observed in the dynamic stretching group compared with the static stretching group (all Ps < 0.01 for hamstring, quadriceps, VAS, and AKPS).

CONCLUSION

In patients with PFP who have inflexible hamstrings, dynamic hamstring stretching with strengthening exercises was superior for improving muscle activation time and clinical outcomes compared with static hamstring stretching with strengthening exercises.

CLINICAL RELEVANCE

Clinicians and therapists could implement dynamic hamstring stretching to improve function and reduce pain in patients with PFP who have inflexible hamstrings.

Current concepts in the management of patellofemoral pain - The role of alignment

BACKGROUND

Patellofemoral pain is a prevalent and significant clinical problem that is often reported to persist even following evidence based intervention. It is clear therefore that there is much about this complex patient group that is not presently fully understood. This is particularly concerning given the reported links between patellofemoral pain in adolescence and the subsequent development of osteoarthritis and anxiety.

ASSESSMENT

Clinical assessment has historically focussed on biomechanical factors such as altered lower limb kinematics, muscle weakness and late muscle 'onset or activation' during activity. However when examined it is clear that study findings from patellofemoral populations are often inconsistent. Reasons for this are discussed and specifically the limitations around current 'gold standard' measurement methods, such as motion capture are outlined. A biomechanical approach is applied to demonstrate the importance of ensuring optimal patient alignment during rehabilitation, where optimal is defined as ensuring the most energy efficient muscle or muscles are used by the patient to perform a movement. This in turn ensures that the direction, magnitude and location of load applied to the skeleton during activity is optimal and therefore less likely to lead to injury.

TREATMENT

The role of alignment in patellofemoral pain and the importance of correcting this during rehabilitation is discussed, and examples provided. Validated, reliable, and reproducible methods of measuring skeletal geometry, muscle geometry, muscle force and direction, and kinematics of activity must be developed as a priority in order for us to further our understanding and improve outcomes in this complex clinical population.

A simple rehabilitation regime improves functional outcome in patients with patellafemoral pain after 12 month

PURPOSE

The purpose of the present study was to investigate the effects of a 3-month multimodal intervention including patient education, a simple hip exercise program, footwear adjustment, and foot orthoses to reduce symptoms in patients with patellafemoral pain (PFP).

METHODS

Patients were diagnosed based on a physical examination, patient symptoms and ruled out intra-articular knee pathologies by MRI. Patients were educated on PFP and participated in a 3-month exercise program; shoes with solid heel-caps were recommended, and custom made orthoses with arch support were recommended to patients with foot pronation. The Anterior Knee Pain Scale (AKPS) and the pain numeric rating scale (NRS) were used to evaluate the outcomes of the intervention and collected at baseline, 3 and 12-months follow-ups.

RESULTS

Sixty-five patients (age 18 years (9-32)) were included in a consecutive prospective cohort. The AKPS score improved from 71 ± 24 to 89 ± 9 (p < 0.01) at 12 months follow up. The NRS-rest and NRS-activity improved from 3 to 0 (p < 0.01) and 7 to 3 (p < 0.01) respectively. 78% of the patients clinically improved (i.e., demonstrated a > 10-point improvement (minimal clinically important difference (MCID))) considering the AKPS; and 76% and 73% clinically improved (i.e., demonstrated (MCID) a ≥ 2-point improvement) in their NRS-rest and NRS-activity, respectively. No patients experienced a decrease in their AKPS score or an increase in their NRS-rest and NRS-activity scores at 12-months.

CONCLUSION

A 3-month PFP multimodal treatment strategy focusing on patient education, footwear adjustment, orthoses, and simple hip muscle exercises significantly improved functional outcomes and reduced pain at a 12 month follow-up.

Isometric exercises and somatosensory training as intervention programmes for patellofemoral pain in young dancers

Patellofemoral pain (PPF) is a common problem experienced by young dancers. Currently, there is no clear indication as to the optimal intervention programme for reducing the level of pain and improving functional abilities in young dancers with PFP. Our aim was to examine the efficacy of two intervention programmes compared with controls in relation to PFP symptoms (shown by pain level, Grinding test, and patellar inhibition test-PIT) and functional abilities of dancers with PFP. Ninety-eight young dancers (mean age 13.4 ± .97) with PFP were assessed for clinical parameters and functional abilities pre and post an intervention programme lasting 12 weeks. Using cluster sampling controlling for grade and school, the dancers were divided into three groups: isometric exercises (IE), somatosensory training (ST), and control (CO). Post-intervention, significantly lower pain levels upon patellar provocation testing were reported for the two treatment groups compared with controls. There was a significantly lower rate of legs recovered in the CO group compared with both intervention groups on the Grinding test, and on the PIT. Postural balance ability and proprioception abilities were significantly better post-treatment for the two treatment groups compared with controls. A significant interaction showed that hip abduction muscle strength improved more in the IE group. In conclusion, both isometric exercises and somatosensory training were effective for decreasing clinical symptoms and improving some functional abilities in young dancers with PFP. Further studies on these types of interventions could determine the most effective training protocol for prevention and treatment of PFP in young dancers.

Effect of manual compressive therapy on latent myofascial trigger point pressure pain thresholds

OBJECTIVE

This study compared the effects of 90 s of manual compressive therapy (MCT) on latent myofascial trigger points (LTPs) for 3 sessions per week for 4 weeks to determine changes in individual pressure pain threshold (PPT). A total of 30 (15 males, 15 females; age = 22 ± 4 y/o, height = 175 ± 18 cm, weight = 162.5 ± 57.5 kg) symptomatic subjects with LTPs volunteered for the study.

METHODS

PPT was measured at baseline and pre- and post-treatment for all 12 sessions with a pressure algometer across the 4-week treatment time frame. The MCT was applied to the control group on their LTP at pressure intended to provide a sham condition (1/10 on verbalized analog scale (VAS)). Two experimental groups had MCT applied either directly on the LTP (d-TP) or in close-proximity to their LTP (cp-TP) at moderate pressure (7/10 on VAS).

RESULTS

There was a significant increase in PPT from the first through twelfth treatment sessions (p < 0.001, partial η² = 0.914). A significant increase in PPTs between treatment groups was acutely observed from pre- to post-therapy tests (p = 0.001, partial η² = 0.146). The differences between pre- versus post-treatment PPT measures indicated significant differences (d-TP vs. control, p < 0.001; cp-TP vs. control, p = 0.007). No differences were observed between experimental groups (p = 0.215).

CONCLUSIONS

PPT continued to increase after several weeks of MCT when applied directly on or within 2.5 cm of an identified LTP compared to control.

Reduction in Thigh Muscle Strength Occurs Concurrently but Does Not Seem to Precede Incident Knee Pain in Women: Data From the Osteoarthritis Initiative Cohort

OBJECTIVE

The aim of the study was to investigate whether muscle strength declines before or concurrent with incident knee pain in subjects with and without radiographic knee osteoarthritis.

DESIGN

Osteoarthritis initiative participants with incident knee pain (occurrence of infrequent/frequent knee pain during the past 12 mos at two consecutive follow-up time points (either years Y3 + Y4 or Y4 + Y5) were compared with controls (no incident knee pain) with 2-yr changes in knee extensor strength during BL➔Y2 (before) and Y2➔Y4 (concurrent).

RESULTS

Two hundred two knees (49% women, 40% radiographic knee osteoarthritis) displayed incident pain, and 439 did not (46% women, 23% radiographic knee osteoarthritis). Women with radiographic knee osteoarthritis displayed a significantly greater (P = 0.04) reduction in knee extensor strength concurrent with incident pain compared with controls (mean = -17.6 N vs. +4.5 N), but men did not. A similar trend was observed in women without radiographic knee osteoarthritis, but this was not statistically significant (P = 0.08). There was no significant relationship with change in extensor strength before incident pain (P ≥ 0.43).

CONCLUSIONS

These results suggest that in women, incident knee pain is accompanied by a concurrent reduction in knee extensor strength, whereas loss in strength does not precede incident knee pain. The findings encourage interventional studies that attempt to attenuate a decline in extensor strength once knee symptoms occur.

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.

Modified exorotation graft tension for tibial fixation in anterior cruciate ligament reconstruction: a randomized controlled trial

Background: The inability of anterior cruciate ligament reconstruction (ACLR) surgery to reduce tibial internal rotation causes many problems. A large tibial internal rotation will result in a patellofemoral pain syndrome. This study aimed to introduce a new technique of modified exorotation graft tension at tibial fixation to minimize endorotation, reduce tibial internal rotation, and prevent patellofemoral pain syndrome.Methods: This study was a randomized double-blind controlled clinical trial. ACL rupture patients underwent ACLR surgery between December 2014 and Februrary 2015. They were randomized to standard endorotation group or modified exorotation group. Hamstring autograft was used and fixed with an EndoButton® and bioabsorbable interference screw. Tibial tubercle to trochlear grove (TTTG) was used to evaluate rotation, whereas cartilage oligomeric matrix protein (COMP) was employed to analyze cartilage breakdown. The functional outcome was measured using the Kujala score to assess patellofemoral joint function. Evaluations were conducted before the surgery and at 6 months postoperation.Results: A total of 29 subjects were recruited. Sixteen subjects were allocated into the standard endorotation group, and 13 were assigned to the modified exorotation group. The exorotation group demonstrated better results than the endorotation group in all three parameters: TTTG (p=0.028), COMP (p<0.001), and Kujala score (p=0.015).Conclusion: A new technique of modified exorotation direction of graft tension for ACL reconstructive surgery at tibial fixation showed a significant reduction in tibial internal rotation and cartilage breakdown. The proposed method could significantly improve the functional outcome of those with total ACL rupture.

Relationship Between Lower-Extremity Strength and Subjective Function in Individuals With Patellofemoral Pain

Objective: Evaluate the relationship between subjective knee function and lower-extremity strength in individuals with patellofemoral pain (PFP). Design: Cohort. Setting: Laboratory. Participants: Participants were 30 individuals with PFP (20 females and 10 males; 76.02 [17.88] kg, 173.04 [7.58] cm, and 24.9 [7] y). Main Outcome Measures: Subjects completed the Activities of Daily Living Scale (ADLS) and had lower-extremity hip and knee isometric strength assessed. Strength was compared between low and high subjective functioning ADLS groups. Correlations for strength and subjective function were assessed, with a linear regression utilized to determine if strength predicted subjective function. Results: Quadriceps strength was significantly greater in the high subjective function group (38.5 [13.9] percent body mass) than in the low subjective function group (27.88 [8.96] percent body mass, P = .02). Significant correlations were seen between the ADLS and all 5 lower-extremity strength measures (r = .376–.535). Quadriceps strength was a strong predictor of subjective function in those with PFP, explaining 28.6% of the total variance in the ADLS. Conclusions: Quadriceps strength was a strong predictor of subjective function when assessed by the ADLS in patients with PFP and significantly greater in those with higher subjective function. A strong relationship exists between self-reported function and lower-extremity strength, suggesting the need to evaluate and treat lower-extremity weakness.

Blood Flow Restriction induces hypoalgesia in recreationally active adult male anterior knee pain patients allowing therapeutic exercise loading

OBJECTIVE

To evaluate if a single blood flow restriction (BFR)-exercise bout would induce hypoalgaesia in patients with anterior knee pain (AKP) and allow painless application of therapeutic exercise.

DESIGN

Cross-sectional repeated measures design.

SETTING

Institutional out-patients physiotherapy clinic.

PATIENTS

Convenience sample of 30 AKP patients.

INTERVENTION

BFR was applied at 80% of complete vascular occlusion. Four sets of low-load open kinetic chain knee extensions were implemented using a pain monitoring model.

MAIN OUTCOME MEASUREMENTS

Pain (0-10) was assessed immediately after BFR application and after a physiotherapy session (45 min) during shallow and deep single-leg squat (SSLS, DSLS), and step-down test (SDT). To estimate the patient rating of clinical effectiveness, previously described thresholds for pain change (≥40%) were used, with appropriate adjustments for baseline pain levels.

RESULTS

Significant effects were found with greater pain relief immediate after BFR in SSLS (d = 0.61, p < 0.001), DSLS (d = 0.61, p < 0.001), and SDT (d = 0.60, p < 0.001). Time analysis revealed that pain reduction was sustained after the physiotherapy session for all tests (d_(SSLS) = 0.60, d_(DSLS) = 0.60, d_(SDT) = 0.58, all p < 0.001). The reduction in pain effect size was found to be clinically significant in both post-BFR assessments.

CONCLUSION

A single BFR-exercise bout immediately reduced AKP with the effect sustained for at least 45 min.

Patellofemoral Cartilage Repair

Purpose of Review

This review provides an overview of well-established and newly developed cartilage repair techniques for cartilage defects in the patellofemoral joint (PFJ). An algorithm will be presented for approaching cartilage defects considering the distinct anatomy of both the patellar and trochlear articular surfaces.

Recent Findings

Recent studies on cartilage repair in the PFJ have demonstrated improved outcomes in an attempt to delay or obviate the need for arthroplasty, and improve symptoms in young patients. While autologous chondrocyte implantation shows good and excellent outcomes for chondral lesions, osteochondral defects are adequately addressed with osteochondral allograft transplantation. In case of patellar malalignment, concomitant tibial tubercle osteotomy can significantly improve outcomes. Particulated cartilage and bone marrow aspirate concentrate are potential new alternative treatments for cartilage repair, currently in early clinical studies.

Summary

Due to the frequency of concomitant anatomic abnormalities in the PFJ, a thorough clinical examination combined with careful indication for each procedure in each individual patient combined with meticulous surgical technique is central to achieve satisfying outcomes. Additional comparative studies of cartilage repair procedures, as well as investigation of newer techniques, are needed.

Female PFP patients present alterations in eccentric muscle activity but not the temporal order of activation of the vastus lateralis muscle during the single leg triple hop test

This study aimed to compare the concentric and eccentric activity and the temporal order of peak activity of the hip and knee muscles between women with patellofemoral pain (PFP) and healthy women during the single leg triple hop test (SLTHT). Electromyographic (EMG) and Kinematic data were collected from 14 healthy women (CG) and 14 women diagnosed with PFP (PFG) during a single session of the single leg triple hop test. Integral surface electromyography (iEMG) data of the hip and knee muscles in eccentric and concentric phases and the length of time that each muscle needed to reach the maximal peak of muscle activity were calculated. The iEMG in the eccentric phase was significantly higher (p < 0.05) than the concentric phase, for the gluteus maximus and gluteus medius muscles (CG and PFG) and for the vastus lateralis muscle (PFG). The vastus lateralis muscle was the first muscle to reach the highest peak of activity in the PFG, and the third to reach this peak in the CG. In the present study, the activity of the vastus lateralis muscle during the eccentric phase of the jump was greater than concentric phase, as a temporal anticipation of its peak in activity among women with PFP.

Is hip strengthening the best treatment option for females with patellofemoral pain? A randomized controlled trial of three different types of exercises

OBJECTIVE

To evaluate the effect of three types of exercise intervention in patients with patellofemoral pain and to verify the contributions of each intervention to pain control, function, and lower extremity kinematics.

METHODS

A randomized controlled, single-blinded trial was conducted. Forty women with patellofemoral pain were randomly allocated into four groups: hip exercises, quadriceps exercises, stretching exercises and a control group (no intervention). Pain (using a visual analog scale), function (using the Anterior Knee Pain Scale), hip and quadriceps strength (using a handheld isometric dynamometer) and measuring lower limb kinematics during step up and down activities were evaluated at baseline and 8 weeks post intervention.

RESULTS

All treatment groups showed significant improvements on pain and Anterior Knee Pain Scale after intervention with no statistically significant differences between groups except when compared to the control group. Only hip and quadriceps groups demonstrated improvements in muscle strength and knee valgus angle during the step activities.

CONCLUSION

Hip strengthening exercises were not more effective for pain relief and function compared to quadriceps or stretching exercises in females with patellofemoral pain. Only hip and quadriceps groups were able to decrease the incidence of dynamic valgus during step-down activity. This study was approved by Brazilian Clinical Trials Registry registration number: RBR-6tc7mj (http://www.ensaiosclinicos.gov.br/rg/RBR-6tc7mj/).

Hip and Knee Strengthening Is More Effective Than Knee Strengthening Alone for Reducing Pain and Improving Activity in Individuals With Patellofemoral Pain: A Systematic Review With Meta-analysis

Study Design Systematic review with meta-analysis. Background The addition of hip strengthening to knee strengthening for persons with patellofemoral pain has the potential to optimize treatment effects. There is a need to systematically review and pool the current evidence in this area. Objective To examine the efficacy of hip strengthening, associated or not with knee strengthening, to increase strength, reduce pain, and improve activity in individuals with patellofemoral pain. Methods A systematic review of randomized and/or controlled trials was performed. Participants in the reviewed studies were individuals with patellofemoral pain, and the experimental intervention was hip and knee strengthening. Outcome data related to muscle strength, pain, and activity were extracted from the eligible trials and combined in a meta-analysis. Results The review included 14 trials involving 673 participants. Random-effects meta-analyses revealed that hip and knee strengthening decreased pain (mean difference, -3.3; 95% confidence interval [CI]: -5.6, -1.1) and improved activity (standardized mean difference, 1.4; 95% CI: 0.03, 2.8) compared to no training/placebo. In addition, hip and knee strengthening was superior to knee strengthening alone for decreasing pain (mean difference, -1.5; 95% CI: -2.3, -0.8) and improving activity (standardized mean difference, 0.7; 95% CI: 0.2, 1.3). Results were maintained beyond the intervention period. Meta-analyses showed no significant changes in strength for any of the interventions. Conclusion Hip and knee strengthening is effective and superior to knee strengthening alone for decreasing pain and improving activity in persons with patellofemoral pain; however, these outcomes were achieved without a concurrent change in strength. Level of Evidence Therapy, level 1a-. J Orthop Sports Phys Ther 2018;48(1):19-31. Epub 15 Oct 2017. doi:10.2519/jospt.2018.7365.

Neuromuscular electrical stimulation (NMES) for patellofemoral pain syndrome

BACKGROUND

Patellofemoral pain syndrome, now generally referred to as patellofemoral pain (PFP), is one of the most common orthopaedic disorders, characterised by pain in the anterior or retropatellar knee region. Neuromuscular electrical stimulation (NMES) has been proposed generally as a complementary treatment, associated with other interventions such as exercise, or as a single treatment to increase muscle force, reduce knee pain, and improve function.

OBJECTIVES

To assess the effects (benefits and harms) of neuromuscular electrical stimulation for people with patellofemoral pain.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PEDro, CINAHL, SPORTDiscus, AMED, LILACS, trial registers, conference abstracts, and reference lists. We carried out the search in May 2017.

SELECTION CRITERIA

We included randomised controlled clinical trials that evaluated the use of NMES for people with PFP.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the process of study selection, data extraction, and 'Risk of bias' assessment in duplicate. The primary outcomes were knee pain, knee function, and adverse events. The timing of outcome measurements was up to three months (short term), three to 12 months (medium term), and 12 months and above from trial entry (long term). We calculated risk ratios for dichotomous data and mean differences or standardised mean differences for continuous data. Where appropriate, we pooled data using the fixed-effect model.

MAIN RESULTS

We included eight randomised clinical trials, reporting results for 345 participants with PFP. The mean ages of trial populations ranged from 25 to 43 years, and the majority (53% to 100%) of participants were female. There was a wide duration of symptoms, with the minimum duration of symptoms for trial inclusion ranging from one to six months. In addition to the study inclusion criteria, studies varied widely in the characteristics of the NMES and its application, and associated co-interventions. We assessed all trials as at high risk of bias in at least one domain, particularly blinding and incomplete outcome data. The results of a laboratory-based trial reporting knee pain immediately after a single 15-minute session of NMES are not reported here as these are of questionable clinical relevance. The seven remaining trials provided evidence for three comparisons. We assessed the overall quality of the evidence, using GRADE, for all primary outcomes for all comparisons as very low, thus we are very unsure of the findings.Four studies compared NMES plus exercise versus exercise alone. Patellar taping was applied as well as exercise to all participants of one study, and patellar taping and ice were also applied in another study. Each trial tested a different multiple-session NMES programme. Pooled data from three studies (118 participants) provided very low-quality evidence that NMES is associated with reduced pain at the end of treatment (ranging from 3 to 12 weeks): mean difference -1.63, 95% confidence interval (CI) -2.23 to -1.02; visual analogue scale (VAS) 0 to 10; higher scores = worse pain. However, this result may not be clinically relevant since the minimal clinically important difference for VAS during activities (1.5 to 2.0, out of 10 points) lies within the 95% CI. We found very low-quality evidence from pooled data from two trials of little effect of NMES on knee function, as measured by two knee function rating systems. We found inconclusive and very low-quality evidence from one trial (29 participants) of little effect of NMES on pain and function at one-year follow-up. None of the four trials reported on adverse effects of treatment.One study (94 participants) compared NMES, applied four hours per day on a daily basis for four weeks, with two types of exercises (isometric and isokinetic). The study did not report on knee pain or adverse events. The study provided very low-quality evidence of no important difference between the two groups in knee function at the end of the four-week treatment. Of note is the potentially onerous NMES schedule in this study, which does not correspond to that typically used in clinical practice.Two studies compared different types of NMES. Simultaneously delivered high-low frequencies NMES was compared with sequentially delivered high-low frequencies NMES in one trial (14 participants) and with fixed frequency NMES in the second trial (64 participants). The studies provided very low-quality evidence of no important differences at the end of the six-week treatment programme between the simultaneous frequencies NMES and the two other NMES programmes in overall knee pain, knee function, or in quadriceps fatigue (an adverse event).

AUTHORS' CONCLUSIONS

This review found insufficient and inconclusive evidence from randomised controlled trials to inform on the role of NMES for treating people with PFP in current clinical practice. The very low-quality evidence available means that we are uncertain whether or not a multiple-session programme of NMES combined with exercise over several weeks versus exercise alone results in clinically important differences in knee pain and function at the end of the treatment period or at one year. There were no data on adverse effects such as muscle fatigue and discomfort. High-quality randomised clinical trials are needed to inform on the use of NMES for people with PFP. However, professional and stakeholder consensus is required on prioritisation of the research questions for interventions for treating people with PFP, including on the NMES treatment protocol for trials testing NMES.

Considerations in Evaluating Treatment Options for Patellofemoral Cartilage Pathology

Patellofemoral (PF) pain, a subset of anterior knee pain, presents a particularly challenging diagnosis due to the multifactorial etiology. Within this group, assigning the patient's symptoms to a patellofemoral cartilage lesion is indirect; that is, a diagnosis by exclusion as hyaline cartilage is aneural. In addition, these PF compartment lesions are often in conjunction with various comorbidities, for example, malalignment and/or instability. In light of these factors and the high shear and compression stresses at the PF compartment, patellar and trochlear chondral lesions require unique treatment considerations from the tibiofemoral compartments. A thorough understanding of the various cartilage restoration techniques available is necessary to select the best option for the individual patient/knee/lesion noting that there is overlap of techniques' applications. In addition, failure to address and correct associated comorbidities may jeopardize the outcome of any cartilage restoration procedure. That is, the key to achieving optimal outcomes with PF cartilage restoration is to select the best cartilage treatment for the particular setting and to concomitantly optimize the PF biomechanical environment and stability.

A Meta-Analysis to Determine if Lower Extremity Muscle Strengthening Should Be Included in Military Knee Overuse Injury-Prevention Programs

CONTEXT

 Knee overuse injuries are the most common musculoskeletal complaints in military trainees and are common in active-duty warfighters. Muscle strengthening is usually recommended; however, research is conflicting in this area, which makes it difficult to develop effective screening, prevention, and training interventions for warfighters.

OBJECTIVE

 To determine if lower extremity muscular weakness contributes to knee overuse injuries and identify specific muscular involvement.

DATA SOURCES

 We searched MEDLINE, PubMed, Web of Science, SPORTDiscus, CINAHL, and Military & Government Collection and reference lists of relevant articles published between January 1, 2000, and January 1, 2013.

STUDY SELECTION

 For inclusion, requirements were uninjured and injured groups; provision of the sample size, means, and standard deviations for all groups; identification of the specific muscles assessed; and clearly defined knee injury.

DATA EXTRACTION

 Sample size, sex, and muscle strength means and standard deviations.

DATA SYNTHESIS

 Twenty-five studies met these criteria. We used the Scottish Intercollegiate Guidelines Network algorithm to determine the appropriate tool for appraising article quality. Unweighted random-effects model meta-analyses were conducted. Separate meta-analyses were performed for the moderators of strength measurement scale (absolute or normalized muscle strength), muscle group, and sex. A weighted random-effects model with a Hedges g effect metric and 95% confidence intervals were used for comparison across studies.

CONCLUSIONS

 Our meta-analysis suggests that individuals with symptoms of a knee overuse injury have lower absolute and normalized hip muscle strength. Specifically, they had lower absolute hip external-rotator, knee-extensor, and knee-flexor strength, as well as lower normalized hip external-rotator, hip-extensor, and hip-abductor strength, compared with asymptomatic control participants. The findings suggest a possible link between lower hip and thigh strength and knee overuse injuries. Further research is needed to determine if weakness is a cause or a result of knee overuse injuries before screening and intervention can be developed for at-risk warfighters.

Impairment based rehabilitation for patellofemoral pain patients

Patellofemoral pain is a common knee pathology that affects a wide range of active individuals. These individuals often seek medical care, with 25% of all patients seen in sports medicine clinics being treated for patellofemoral pain. While conservative treatment produce beneficial short-term results, individuals with patellofemoral pain often have long-term pain and decreased quality of life for many years following their diagnosis. One of the challenges for treating this chronic condition is the heterogeneous presentation of impairments across patients, ranging from soft tissue restriction, muscle weakness, altered movement patterns during functional tasks, and weak core stability. Clinicians need to identify these impairments and develop an individualized impairment-based model for treating patients with PFP. The aim of this review it to provide guidance and recommendations for clinicians who treat PFP in hopes to improve long-term outcomes for the conservative treatment of PFP.

The effect of exercise on vastus medialis oblique muscle architecture: An ultrasound investigation

The vastus medialis oblique (VMO) is thought to be implicated in patellofemoral pain (PFP), and weakness in this portion of the vastus medialis muscle may lead to PFP. Management includes physiotherapy to strengthen the VMO. Although this intervention has been shown to be effective, the effects on the architecture of the muscle have not been investigated. This study aims to determine the changes in VMO architecture following a program of strengthening exercises. Twenty-one male participants underwent an initial ultrasound scan to measure the fiber angle and the insertion level of the VMO on the patella. Each subject then undertook a 6-week quadriceps femoris strengthening program; the scan and measurements were then repeated. A significant increase in VMO fiber angle and insertion length was observed. Average fiber angle increased by 5.24°; average insertion length increased by 2.7 mm. There was found to be a significant negative correlation between the initial values and the degree of change. Pearson's coefficient of correlation for measurements of patella length taken before and after exercise was 0.921, indicating a high degree of reliability. There was a significant positive correlation between fiber angle change and declared level of compliance (R(2)  = 0.796). The results reported here indicate that physiotherapy leads to a significant change in VMO morphology. Given the inverse correlation noted between initial architectural parameters and the degree of change, we suggest that patients who would benefit most from physiotherapy can be identified in clinic using a simple ultrasound technique. Clin. Anat. 29:752-758, 2016. © 2016 Wiley Periodicals, Inc.

Effect of leg press training on patellar realignment in patients with patellofemoral pain

[Purpose] The purpose of this study was to investigate the effect of leg press and leg press with hip adduction exercise training on patellar alignment and pain in patients with patellofemoral pain (PFP). [Subjects and Methods] Seventeen patients participated in this study. Eight weeks of leg press or leg press with hip adduction training, including progressive lower-limb weight-training and stretching, was given. Patellar alignment (tilt and displacement) and pain measurements were conducted before and after leg press or leg press with hip adduction training. Patellar tilt angle and the bisect offset index were measured on axial computed tomography scans of the fully extended knee position with the quadriceps relaxed and contracted. Pain was assessed by using a 10-cm visual analog scale. [Results] No differences were found in patellar tilt and displacement with the quadriceps either relaxed or contracted after leg press and leg press with hip adduction. However, significant pain reduction was evident in both leg press and leg press with hip adduction. [Conclusion] The results indicated that patellar realignment does not appear to mediate pain alleviation. Furthermore, hip adduction in addition to leg press training had no additive beneficial effect on patellar realignment or pain reduction.

Which patellofemoral joint imaging features are associated with patellofemoral pain? Systematic review and meta-analysis

OBJECTIVES

To review the association between patellofemoral joint (PFJ) imaging features and patellofemoral pain (PFP).

DESIGN

A systematic review of the literature from AMED, CiNAHL, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PEDro, EMBASE and SPORTDiscus was undertaken from their inception to September 2014. Studies were eligible if they used magnetic resonance imaging (MRI), computed tomography (CT), ultrasound (US) or X-ray (XR) to compare PFJ features between a PFP group and an asymptomatic control group in people <45 years of age. A pooled meta-analysis was conducted and data was interpreted using a best evidence synthesis.

RESULTS

Forty studies (all moderate to high quality) describing 1043 people with PFP and 839 controls were included. Two features were deemed to have a large standardised mean difference (SMD) based on meta-analysis: an increased MRI bisect offset at 0° knee flexion under load (0.99; 95% CI: 0.49, 1.49) and an increased CT congruence angle at 15° knee flexion, both under load (1.40 95% CI: 0.04, 2.76) and without load (1.24; 95% CI: 0.37, 2.12). A medium SMD was identified for MRI patella tilt and patellofemoral contact area. Limited evidence was found to support the association of other imaging features with PFP. A sensitivity analysis showed an increase in the SMD for patella bisect offset at 0° knee flexion (1.91; 95% CI: 1.31, 2.52) and patella tilt at 0° knee flexion (0.99; 95% CI: 0.47, 1.52) under full weight bearing.

CONCLUSION

Certain PFJ imaging features were associated with PFP. Future interventional strategies may be targeted at these features.

PROSPERO REGISTRATION NUMBER

CRD 42014009503.

Knee orthoses for treating patellofemoral pain syndrome

BACKGROUND

Patellofemoral pain syndrome (PFPS) is a painful musculoskeletal condition, which is characterised by knee pain located in the anterior aspect (front) and retropatellar region (behind) of the knee joint. Various non-operative interventions are suggested for the treatment of this condition. Knee orthoses (knee braces, sleeves, straps or bandages) are worn over the knee and are thought to help reduce knee pain. They can be used in isolation or in addition to other treatments such as exercise or non-steroidal anti-inflammatory medications.

OBJECTIVES

To assess the effects (benefits and harms) of knee orthoses (knee braces, sleeves, straps or bandages) for treating PFPS.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (11 May 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2015 Issue 5), MEDLINE (1946 to 8 May 2015), EMBASE (1980 to 2015 Week 18), SPORTDiscus (1985 to 11 May 2015), AMED (1985 to 8 May 2015), CINAHL (1937 to 11 May 2015), PEDro (1929 to June 2015), trial registries and conference proceedings.

SELECTION CRITERIA

Randomised and quasi-randomised controlled clinical trials evaluating knee orthoses for treating people with PFPS. Our primary outcomes were pain and function.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for eligibility, assessed study risk of bias and extracted data. We calculated mean differences (MD) or, where pooling data from different scales, standardised mean differences (SMD) with 95% confidence intervals (CI) for continuous outcomes and risk ratios (RR) with 95% CIs for binary outcomes. We pooled data using the fixed-effect model.

MAIN RESULTS

We included five trials (one of which was quasi-randomised) that reported results for 368 people who had PFPS. Participants were recruited from health clinics in three trials and were military recruits undergoing training in the other two trials. Although no trials recruited participants who were categorised as elite or professional athletes, military training does comprise intensive exercise regimens. All five trials were at high risk of bias, including performance bias reflecting the logistical problems in these trials of blinding of participants and care providers. As assessed using the GRADE approach, the available evidence for all reported outcomes is 'very low' quality. This means that we are very uncertain about the results.The trials covered three different types of comparison: knee orthosis and exercises versus exercises alone; one type of orthosis versus another; and knee orthosis versus exercises. No trials assessed the mode of knee orthosis use, such as whether the orthosis was worn all day or only during physical activity. Two trials had two groups; two trials had three groups; and one trial had four groups.All five trials compared a knee orthosis (knee sleeve, knee brace, or patellar strap) versus a 'no treatment' control group, with all participants receiving exercises, either through a military training programme or a home-based exercise programme. There is very low quality evidence of no clinically important differences between the two groups in short-term (2 to 12 weeks follow-up) knee pain based on the visual analogue scale (0 to 10 points; higher scores mean worse pain): MD -0.46 favouring knee orthoses, 95% CI -1.16 to 0.24; P = 0.19; 234 participants, 3 trials). A similar lack of clinically important difference was found for knee function (183 participants, 2 trials). None of the trials reported on quality of life measures, resource use or participant satisfaction. Although two trials reported on the impact on sporting or occupational participation, one trial (35 participants) did not provide data split by treatment group on the resumption of sport activity and the other reported only on abandonment of military training due to knee pain (both cases were allocated a knee orthosis). One trial (59 participants, 84 affected knees) recording only adverse events in the two knee orthoses (both were knee sleeves) groups, reported 16 knees (36% of 44 knees) had discomfort or skin abrasion.Three trials provided very low quality evidence on single comparisons of different types of knee orthoses: a knee brace versus a knee sleeve (63 participants), a patella strap with a knee sleeve (31 participants), and a knee sleeve with a patellar ring versus a knee sleeve only (44 knees). None of three trials found an important difference between the two types of knee orthosis in pain. One trial found no clinically important difference in function between a knee brace and a knee sleeve. None of the three trials reported on quality of life, resource use or participant satisfaction. One trial comparing a patella strap with a knee sleeve reported that both participants quitting military training due to knee pain were allocated a knee sleeve. One poorly reported trial found three times as many knees with adverse effects (discomfort or skin abrasion) in those given knee sleeves with a patella ring than those given knee sleeves only.One trial compared a knee orthosis (knee brace) with exercise (66 participants). It found very low quality evidence of no clinically important difference between the two intervention groups in pain or knee function. The trial did not report on quality of life, impact on sporting or occupational participation, resource use, participant satisfaction or complications.

AUTHORS' CONCLUSIONS

Overall, this review has found a lack of evidence to inform on the use of knee orthoses for treating PFPS. There is, however, very low quality evidence from clinically heterogeneous trials using different types of knee orthoses (knee brace, sleeve and strap) that using a knee orthosis did not reduce knee pain or improve knee function in the short term (under three months) in adults who were also undergoing an exercise programme for treating PFPS. This points to the need for good-quality clinically-relevant research to inform on the use of commonly-available knee orthoses for treating PFPS.

The results of an extensive soft-tissue procedure in the treatment of obligatory patellar dislocation in children with ligamentous laxity

In 11 paediatric patients (seven girls and four boys, from 12 to 15 years old) with unilateral obligatory patellar dislocation and ligamentous laxity vastus medialis advancement, lateral release, partial patellar ligament transposition and Galeazzi semitendinosus tenodesis was undertaken to stabilise the patella. The diagnostic criterion for ligamentous laxity was based on the Beighton scale. Outcomes were evaluated radiologically and functionally by measurement of the range of knee movement and isokinetic testing. The evaluation also included the Lysholm knee scale. Follow-up studies took place at a mean of 8.1 years (5 to 15) post-operatively.

Normal patellar tracking without any recurrence of dislocation was obtained in ten out of 11 patients. Pain related to vigorous activity was reported by nine patients. Compared with the opposite normal side, the isokinetic tests revealed a statistically significant decrease in the maximal torque values for the affected quadriceps muscle (p = 0.003 and p = 0.004), but no difference between the knee flexors (for angular velocities of 60°/s and 180°/s) (p = 0.858 and p = 0.79).

The applied surgical technique generally prevents the recurrence of the disorder in children with habitual patellar dislocation and ligamentous laxity. Quadriceps muscle weakness can be expected to occur post-operatively,

Cite this article: Bone Joint J 2015;96-B:129–33.

Patellofemoral joint osteoarthritis: an individualised pathomechanical approach to management

Patellofemoral joint integrity is maintained by an optimal interaction of passive, dynamic and structural restraints. Disruption of these mechanics can lead to structural joint damage and subsequent patellofemoral osteoarthritis, which is a prevalent and disabling condition with few effective conservative management strategies. Due to the influential role of biomechanics in this disease, targeting the specific pathomechanics exhibited by an individual is logical to improve their likelihood of a positive treatment outcome. This review summarises the effect of different pathomechanical factors on the presence and progression of patellofemoral osteoarthritis. It then presents a synthesis of mechanical effect of treatment strategies specifically addressing these pathomechanics. Identifying the pathomechanics and clinical characteristics of individuals with patellofemoral osteoarthritis that respond to treatment may assist in the development of individualised treatment strategies that alleviate symptoms and slow structural damage.

Cohort study design: an underutilized approach for advancement of evidence-based and patient-centered practice in athletic training

OBJECTIVE

Providing patient-centered care requires consideration of numerous factors when making decisions that will influence a patient's health status.

BACKGROUND

Clinical decisions should be informed by relevant research evidence, but the literature often lacks pertinent information for problems encountered in routine clinical practice. Although a randomized clinical trial provides the best research design to ensure the internal validity of study findings, ethical considerations and the competitive culture of sport often preclude random assignment of patients or participants to a control condition.

CLINICAL ADVANTAGES

A cohort study design and Bayesian approach to data analysis can provide valuable evidence to support clinical decisions. Dichotomous classification of both an outcome and 1 or more predictive factors permits quantification of the likelihood of occurrence of a specified outcome.

CONCLUSIONS

Multifactorial prediction models can reduce uncertainty in clinical decision making and facilitate the individualization of treatment, thereby supporting delivery of clinical services that are both evidence based and patient centered.

Effects of functional stabilization training on pain, function, and lower extremity biomechanics in women with patellofemoral pain: a randomized clinical trial

STUDY DESIGN

Randomized clinical trial.

OBJECTIVES

To compare the effects of functional stabilization training (FST) versus standard training on knee pain and function, lower-limb and trunk kinematics, trunk muscle endurance, and eccentric hip and knee muscle strength in women with patellofemoral pain.

BACKGROUND

A combination of hip- and knee-strengthening exercise may be more beneficial than quadriceps strengthening alone to improve pain and function in individuals with patellofemoral pain. However, there is limited evidence of the effectiveness of these exercise programs on the biomechanics of the lower extremity.

METHODS

Thirty-one women were randomized to either the FST group or standard-training group. Patients attended a baseline assessment session, followed by an 8-week intervention, and were reassessed at the end of the intervention and at 3 months after the intervention. Assessment measures were a 10-cm visual analog scale for pain, the Lower Extremity Functional Scale, and the single-leg triple-hop test. A global rating of change scale was used to measure perceived improvement. Kinematics were assessed during the single-leg squat. Outcome measures also included trunk endurance and eccentric hip and knee muscle strength assessment.

RESULTS

The patients in the FST group had less pain at the 3-month follow-up and greater global improvement and physical function at the end of the intervention compared to those in the standard-training group. Lesser ipsilateral trunk inclination, pelvis contralateral depression, hip adduction, and knee abduction, along with greater pelvis anteversion and hip flexion movement excursions during the single-leg squat, were only observed in the FST group after the intervention. Only those in the FST group had greater eccentric hip abductor and knee flexor strength, as well as greater endurance of the anterior, posterior, and lateral trunk muscles, after training.

CONCLUSION

An intervention program consisting of hip muscle strengthening and lower-limb and trunk movement control exercises was more beneficial in improving pain, physical function, kinematics, and muscle strength compared to a program of quadriceps-strengthening exercises alone.

Posterolateral hip muscle strengthening versus quadriceps strengthening for patellofemoral pain: a comparative control trial

OBJECTIVE

To compare the efficacy of posterolateral hip muscle strengthening versus quadriceps strengthening in reducing pain and improving health status in persons with patellofemoral pain (PFP).

DESIGN

Comparative control trial.

SETTING

Rehabilitation facility.

PARTICIPANTS

Persons with a diagnosis of PFP (N=36; 18 men, 18 women).

INTERVENTIONS

Patients were alternately assigned to a posterolateral hip muscle strengthening group (9 men and 9 women) or a quadriceps strengthening group (9 men and 9 women). The posterolateral hip muscle strengthening group performed hip abductor and external rotator strengthening exercises, whereas the quadriceps strengthening group performed quadriceps strengthening exercises (3 times a week for 8wk).

MAIN OUTCOME MEASURES

Pain (visual analog scale [VAS]) and health status (Western Ontario McMaster Universities Osteoarthritis Index [WOMAC]) were assessed at baseline, postintervention, and 6-month follow-up.

RESULTS

Significant improvements in VAS and WOMAC scores were observed in both groups from baseline to postintervention and baseline to 6-month follow-up (P<.001). Improvements in VAS and WOMAC scores in the posterolateral hip exercise group were superior to those in the quadriceps exercise group postintervention and at 6-month follow-up (P<.05).

CONCLUSIONS

Although both intervention programs resulted in decreased pain and improved function in persons with PFP, outcomes in the posterolateral hip exercise group were superior to the quadriceps exercise group. The superior outcomes obtained in the posterolateral hip exercise group were maintained 6 months postintervention.