Causes Of Patellofemoral Pain Research Articles

Males with patellofemoral pain have altered movements during step-down and single-leg squatting tasks compared to asymptomatic males: A cross-sectional study.

Patellofemoral pain (PFP) is common in males, causing reduced physical activity and chronic pain. One proposed cause of PFP is aberrant biomechanics during tasks loading the patellofemoral joint. Consistent evidence exists for females with PFP, but it is uncertain if males with PFP have altered biomechanics. This study investigated the kinematics of males with PFP compared to pain-free males during forward step-down (StDn) and single-leg squat (SLSq). A cross-sectional study including 40 males aged 20-39 years (28.28 ± 5.46) was conducted (20 PFP, 20 pain-free). Participants performed StDn and SLSq while motion was captured with a video-based motion capture system (Motion Analysis Corporation). Triplanar peak angles and angular ranges of motion (ROM) of the trunk, pelvis, and weight-bearing hip, knee, and ankle were dependent variables. Mixed-model ANOVA tests were used to determine the presence of significant interactions and main effects of group and task. Males with PFP had significantly lower peak knee adduction angles compared to pain-free males (p = 0.01). Significant group x task interactions were found for hip and pelvis ROM (p < 0.05). PFP participants had increased hip and pelvis ROM during StDn in the frontal and transverse planes but reduced or nearly equal ROM for these variables during SLSq. Peak hip adduction, hip internal rotation, contralateral pelvic drop and anterior tilt, trunk flexion, and ankle dorsiflexion were greater during StDn compared to SLSq (p < 0.05). ROM of the hip, pelvis, trunk, and ankle were greater during StDn compared to SLSq (p < 0.05). Males with PFP had reduced peak knee adduction angles in StDn and SLSq. Males with PFP demonstrated increased hip and pelvis ROM during StDn versus SLSq, particularly in the frontal and transverse planes. Clinicians should consider StDn as a clinical test since aberrant movement may be easier to detect than in SLSq.

Developing a Community-Based Exercise and Physical Programme for Runners With Patellofemoral Pain in Under-Resourced Communities: A Delphi Study

Background: Patellofemoral pain (PFP) is a multifactorial condition that is highly prevalent among recreational runners. Poor homeostasis between load and runner's capacity is the main cause of PFP. A low-cost and community-based intervention is needed to address the rehabilitation needs of runners in under-resourced communities. Purpose: To develop a community-based exercise and physical programme for runners with PFP in under-resourced communities. Method: This study used a Delphi method that included sports experts (physicians, physiotherapists, biokineticists, podiatrists, and sports therapists) who consented to participate. Delphi included three rounds of iterations to attain consensus among experts. Experts reached a consensus by rating PFP programme items using the 5-point Likert scale. Results: Ten experts participated. There were more males ( n = 6) than females ( n = 4). Participants were aged between 36 and 55 years ( n = 5) and had 16-20 years of clinical experience ( n = 5). Delphi process yielded an exercise and physical intervention, which included the following 10 recommended strategies: hip muscle training, quadriceps muscle training, general lower limb and trunk strengthening, use of appropriate running shoes, and use of prefabricated in-shoe foot orthosis, tissue mobilisation, patellar taping/bracing, education, flexibility exercises, addressing external loads, and addressing nonphysical internal loads. Conclusions: A consensus was reached for a suitable exercise and physical programme for runners in under-resourced communities. A follow-up implementation study is, therefore, recommended.

Tibial Torsion and Patellofemoral Pain and Instability in the Adult Population: Current Concept Review

Tibial torsion is a recognized cause of patellofemoral pain and instability in the paediatric population; however, it is commonly overlooked in the adult population. The aim of this review article is to summarize the current best evidence on tibial torsion for the adult orthopaedic surgeon. The true incidence of tibial torsion in the adult population is unknown, with significant geographical variations making assessment very difficult. CT currently remains the gold standard for quantitatively assessing the level of tibial torsion and allows assessment of any associated femoral and knee joint rotational anomalies. Surgical correction should only be considered after completion of a course of physiotherapy aimed at addressing the associated proximal and gluteal weakness. Tibial torsion greater than 30° is used as the main indicator for tibial de-rotation osteotomy by the majority of authors. In patients with associated abnormal femoral rotation, current evidence would suggest that a single-level correction of the tibia (if considered to be a dominant deformity) is sufficient in the majority of cases. Proximal de-rotational osteotomy has been more commonly reported in the adult population and confers the advantage of allowing simultaneous correction of patella alta or excessive tubercle lateralization. Previous surgery prior to de-rotational osteotomy is common; however, in patients with persistent symptoms surgical correction still provides significant benefit. Tibial torsion persists into adulthood and can play a significant role in patellofemoral pathology. A high index of suspicion is required in order to identify torsion clinically. Surgical correction is effective for both pain and instability, but results are inferior in patients with very high pain levels pre-surgery and multiple previous surgeries.

A Contemporary Approach to Patellofemoral Pain in Runners.

Patellofemoral pain (PFP) is among the most common injuries in recreational runners. Current evidence does not identify alignment, muscle weakness, and patellar maltracking or a combination of these as causes of PFP. Rather than solely investigating biomechanics, we suggest a holistic approach to address the causes of PFP. Both external loads, such as changes in training parameters and biomechanics, and internal loads, such as sleep and psychological stress, should be considered. As for the management of runners with PFP, recent research suggested that various interventions can be considered to help symptoms, even if these interventions target biomechanical factors that may not have caused the injury in the first place. In this Current Concepts article, we describe how the latest evidence on education about training modifications, strengthening exercises, gait and footwear modifications, and psychosocial factors can be applied when treating runners with PFP. The importance of maintaining relative homeostasis between load and capacity will be emphasized. Recommendations for temporary or longer-term interventions will be discussed. A holistic, evidence-based approach should consist of a graded exposure to load, including movement, exercise, and running, while considering the capacity of the individual, including sleep and psychosocial factors. Cost, accessibility, and the personal preferences of patients should also be considered.

A Word of Caution for Future Studies in Patellofemoral Pain: A Systematic Review With Meta-analysis

Background: Patellar maltracking is widely accepted as an underlying mechanism of patellofemoral pain. However, methodological differences in the literature hinder our ability to generate a universal quantitative definition of pathological patellofemoral kinematics (patellar maltracking) in patellofemoral pain, leaving us unable to determine the cause of patellofemoral pain. Purpose: To systematically review the literature to provide evidence regarding the influence of confounding variables on patellofemoral kinematics. Study Design: Systematic review and random effects meta-analysis of control-case studies. Methods: A literature search of case-control studies that evaluated patellofemoral kinematics at or near full extension and were written in English was conducted using Embase, PubMed, Scopus, and Web of Science up to September 2019. Cases were defined as patients with patellofemoral pain. Studies were eliminated if they lacked quantitative findings; had a primary aim to assess therapy efficacy; or included participants with osteoarthritis and/or previous trauma, pathology, or surgery. A quality assessment checklist was employed to evaluate each study. Meta-analyses were conducted to determine the influence of confounding variables on measures of patellofemoral kinematics. Results: Forty studies met the selection criteria, with quality scores ranging from 13% to 81%. Patient characteristics, data acquisition, and measurement methods were the primary sources of methodological variability. Active quadriceps significantly increased lateral shift (standardized mean difference [SMD]shift = 0.33; P = .0102) and lateral tilt (SMDtilt = 0.43; P = .006) maltracking. Individuals with pain secondary to dislocation had greater effect sizes for lateral maltracking than had those with isolated patellofemoral pain (ΔSMDshift = 0.71, P = .0071; ΔSMDtilt = 1.38, P = .0055). Conclusion: This review exposed large methodological variability across the literature, which not only hinders the generalization of results, but ultimately mitigates our understanding of the underlying mechanism of patellofemoral pain. Although our meta-analyses support the diagnostic value of maltracking in patellofemoral pain, the numerous distinct methods for measuring maltracking and the limited control for cofounding variables across the literature prohibit defining a single quantitative profile. Compliance with specific standards for anatomic and outcome measures must be addressed by the scientific and clinical community to establish methodological uniformity in this field.

In-vivo patellar tracking in individuals with patellofemoral pain and healthy individuals.

Understanding of the exact cause of patellofemoral pain has been limited by methodological challenges to evaluate in-vivo joint motion. This study compared six degree-of-freedom patellar motion during a dynamic lunge task between individuals with patellofemoral pain and healthy individuals. Knee joints of eight females with patellofemoral pain and ten healthy females were imaged using a CT scanner in supine lying position, then by a dual-orthogonal fluoroscope while they performed a lunge. To quantify patellar motion, the three-dimensional models of the knee bones, reconstructed from CT scans, were registered on the fluoroscopy images using the Fluomotion registration software. At full knee extension, the patella was in a significantly laterally tilted (PFP: 11.77° ± 7.58° vs. healthy: 0.86° ± 4.90°; p = 0.002) and superiorly shifted (PFP: 17.49 ± 8.44 mm vs. healthy: 9.47 ± 6.16 mm, p = 0. 033) position in the patellofemoral pain group compared with the healthy group. There were also significant differences between the groups for patellar tilt at 45°, 60°, and 75° of knee flexion, and for superior-inferior shift of the patella at 30° flexion (p ≤ 0.031). In the non-weight-bearing knee extended position, the patella was in a significantly laterally tilted position in the patellofemoral pain group (7.44° ± 6.53°) compared with the healthy group (0.71° ± 4.99°). These findings suggest the critical role of passive and active patellar stabilizers as potential causative factors for patellar malalignment/maltracking. Future studies should investigate the associations between patellar kinematics with joint morphology, muscle activity, and tendon function in a same sample for a thorough understanding of the causes of patellofemoral pain. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Association Between Measures of Patella Height, Morphologic Features of the Trochlea, and Patellofemoral Joint Alignment: The MOST Study

Patellofemoral joint (PFJ) malalignment (lateral patella displacement and tilt) has been proposed as a cause of patellofemoral pain. Patella height and/or the morphologic features of the femoral trochlea may predispose one to patella malalignment. The purposes of our study were to assess the associations among patella height, morphologic features of the trochlea, and measures of PFJ alignment and to determine which measures of patella height and morphologic features of the trochlea were the best predictors of PFJ alignment. Measures of patella height (Insall-Salvati ratio and modified Insall-Salvati ratio), morphologic features of the trochlea (sulcus angle, trochlear angle, lateral trochlear inclination, medial trochlear inclination), and PFJ alignment (bisect offset and patella tilt angle) were assessed in 566 knees from the Multicenter Osteoarthritis Study. Bisect offset was correlated with the Insall-Salvati ratio (r = 0.25) and lateral trochlear inclination (r = -0.38). Patella tilt angle correlated with the trochlear angle (-0.27) and lateral trochlear inclination (-0.32). Linear regression models including the Insall-Salvati ratio and lateral trochlear inclination explained 20% and 11% of the variance in bisect offset and patella tilt angle, respectively. Of the variables measured in the current study, the Insall-Salvati ratio and lateral trochlear inclination were the best predictors of lateral patella displacement and lateral tilt. This knowledge will aid clinicians in the identification of anatomic risk factors for PFJ malalignment and/or PFJ dysfunction.

Using real‐time MRI to quantify altered joint kinematics in subjects with patellofemoral pain and to evaluate the effects of a patellar brace or sleeve on joint motion

Abnormal patellofemoral joint motion is a possible cause of patellofemoral pain, and patellar braces are thought to alleviate pain by restoring normal joint kinematics. We evaluated whether females with patellofemoral pain exhibit abnormal patellofemoral joint kinematics during dynamic, weight-bearing knee extension and assessed the effects of knee braces on patellofemoral motion. Real-time magnetic resonance (MR) images of the patellofemoral joints of 36 female volunteers (13 pain-free controls, 23 patellofemoral pain) were acquired during weight-bearing knee extension. Pain subjects were also imaged while wearing a patellar-stabilizing brace and a patellar sleeve. We measured axial-plane kinematics from the images. Females with patellofemoral pain exhibited increased lateral translation of the patella for knee flexion angles between 0 degrees and 50 degrees (p = 0.03), and increased lateral tilt for knee flexion angles between 0 degrees and 20 degrees (p = 0.04). The brace and sleeve reduced the lateral translation of the patella; however, the brace reduced lateral displacement more than the sleeve (p = 0.006). The brace reduced patellar tilt near full extension (p = 0.001), while the sleeve had no effect on patellar tilt. Our results indicate that some subjects with patellofemoral pain exhibit abnormal weight-bearing joint kinematics and that braces may be effective in reducing patellar maltracking in these subjects.

Comparison of Patellar Mobility in Female Adults With and Without Patellofemoral Pain

Case control study. To compare the patellar mobility of female adult subjects with and without patellofemoral pain (PFP). Although abnormal patellar mobility is believed to be one of the causes of PFP, there is currently no published evidence to support this contention. In part, this lack of evidence is because a reliable clinical measurement method to measure patellar mobility and objective criteria to define abnormal patellar mobility have not been established. The study sample was comprised of 22 females with PFP (PFP group) and 22 females who had no knee pain (control group), matched by age, height, and body mass index to the subjects with PFP. Patellar mobility was measured objectively using a specially designed apparatus. Measurements of lateral and medial patellar displacement, patellar mobility balance (lateral minus medial patellar displacement), lateral patellar mobility index (lateral patellar displacement divided by patellar width), and medial patellar mobility index (medial patellar displacement divided by patellar width) were used. Lateral and medial patellar mobility values were not significantly different between the individuals in the PFP and control groups. When normal patellar mobility was arbitrarily defined as the average mobility +/- 2 SDs, based on the data from the control group, normal lateral patellar displacement was within a range of 7.2 to 17.6 mm and normal medial patellar displacement was within a range of 6.8 to 14.0 mm. The intraclass correlation coefficient for intratester and intertester reliability of lateral and medial patellar displacement measurements varied from 0.80 to 0.97. Although there were no significant differences in patellar mobility between females with and without PFP, these measurements give reference information about normal patellar mobility for this group. Diagnosis, level 5.

Patellofemoral pain syndrome

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

The Effect of Vastus Medialis Forces on Patello-femoral Contact: A Model-based Study

A mathematical model of the patello-femoral joint was introduced to investigate the impact of the vastus medialis (longus, obliquus) forces on the lateral contact force levels. In the model, the quadriceps were represented as five separate forces: vastus lateralis, vastus intermedius, rectus femoris, vastus medialis longus (VML), and obliquus (VMO). By varying the relative force generation ratios of the quadriceps heads, the patello-femoral contact forces were estimated. We sought to analytically determine the range of forces in the VMO and VML that cause a reduction or an increase of lateral contact forces, often the cause of patello-femoral pain. Our results indicated that increased contact forces are more dependent on combinations of muscle forces than solely VMO weakness. Moreover, our simulation data showed that the contact force levels are also highly dependent on the knee flexion angle. These findings suggest that training targeted to reduce contact forces through certain joint angles could actually result in a significant increase of the contact forces through other joint angles.

Sonographic appearance of fibrous nodules in patellar clunk syndrome: a case report

AbstractPatellar clunk syndrome is a rare complication causing pain after total knee arthroplasty. However, it is important to differentiate it from the other causes of patellofemoral pain. In this article, we apply ultrasonography for the first time to demonstrate the suprapatellar fibrous tissue causing this condition. A 50-year-old woman with rheumatoid arthritis had left total knee arthroplasty. The patient had excellent results until 2 years after surgery, when she complained of anterior knee pain. On physical examination, a patellar“catch” and “pop” were noted from 45° flexion to full extension. Roentgenograms showed a radiolucent line at the upper pole of the patella and no subluxation of the patella on skyline view. Sagittal and transverse gray-scale sonographic images revealed an echogenic area attached to the quadriceps tendon. Corresponding color Doppler sonographic images showed marked vascularity in this echogenic area. The patient was treated with removal of the suprapatellar tissue and a patellar component revision. Intraoperatively, the suprapatellar tissue, which measured 4 × 4 × 2 cm, entered the notch area of the femoral component on flexion and caused the patellar “pop” on knee extension. Pain relief was obtained immediately after the operation when smooth gliding motion of the patella was restored.

Practical management of patellofemoral pain.

Patellofemoral pain (PFP) is one of the most common disorders of the knee, accounting for 25% of all knees injuries seen in a sports medicine clinic. The cause of PFP, however, is not clearly understood and may consist of multiple origins. The most commonly accepted hypothesis is related to increased patellofemoral joint stress (force per unit area) and subsequent articular cartilage wear. Athletes typically note the insidious onset of an illdefined ache localized to the anterior knee, behind the patella. Occasionally the pain may be centered along the medial or lateral patellofemoral joint and retinaculum. Typically, pain is aggravated with functions that increase patellofemoral compressive forces, such as ascending and descending hills or stairs, squatting, and prolonged sitting with the knee in a flexed position. While clinical studies have not been able to consistently demonstrate biomechanical or alignment differences between patients with patellofemoral pain and healthy individuals, a systematic exam may highlight predisposing factors. The location of symptoms may indicate the specific structures involved and may give direction with respect to making a differential diagnosis: lateral pain—small nerve injury of the lateral retinaculum, or iliotibial band friction syndrome; medial pain—recurrent stretching of the medial retinaculum or symptomatic medial plica; retropatellar pain—articular cartilage damage or stress on the subchondral bone; superior pain—quadriceps tendinitis; inferior pain—patellar tendinitis or fat pad irritation. When making a diagnosis of PFP, it is important to rule out other disorders. For example, joint line tenderness may be indicative of meniscal injury or femorotibial arthritis, and more vague pain patterns may indicate referred pain from the hip or the L2–L4 nerve roots. Magnetic resonance imaging (MRI) is particularly helpful at assessing degenerative joint changes such as cartilage fissuring or thinning, subchondral bone marrow edema, subchondral cysts, synovial plica, and patellar tendinitis. If more definitive information is required regarding patellar tracking, kinematic studies can be obtained with MRI or computed tomography (CT). To more accurately define patellar tracking abnormalities at our institution, we are now using an MR unit in which the patient can stand upright in a weight-bearing position while performing continuous flexion and extension movements (Figure 1).

ARTHROSCOPY OF THE PATELLOFEMORAL JOINT

There are multiple causes of patellofemoral pain that can be difficult to differentiate. A careful history and physical examination along with appropriate radiographic evaluation lead to the correct diagnosis in most cases. Most patients respond to a comprehensive nonoperative program that emphasizes stretching and strengthening of the quadriceps mechanism. Arthroscopy should be used judiciously when approaching patellofemoral problems. Regarding alignment, arthroscopy offers little benefit but may provide visualization for lateral release to relieve tilt. Arthroscopy of the patellofemoral joint does provide valuable information about articular cartilage breakdown location, extent, and pattern, which may help with future treatment decisions. Arthroscopy is helpful in the diagnosis and treatment of plicae and in ruling out other intraarticular causes of knee pain.

Historical Background: Patellofemoral Pain in Young People

This article examines the evolution of the current understanding of what patellofemoral pain is, or is not, in young people. It focuses on the articular cartilage of the patella because chondromalacia patellae (softened articular cartilage) was almost unanimously presumed to be the primary cause of patellofemoral pain in young people until recently.

Excessive Lateral Pressure as a Cause of Patello-Femoral Pain syndrome

SummaryThe purpose of this paper is to show that a significant number of patients presenting with patello-femoral pain have excessive lateral pressure (ELP) which can be diagnosed using clinical, radiographic and arthroscopic examinations.The aetiology of ELP as a cause of patello-femoral pain is discussed. A series of 93 patients are presented, many of whom showed some of the four suggested signs of ELP. The investigations and findings are shown in relation to the varying aetiologies of patello-femoral pain.

The Etiology of Patellofemoral Pain in Young, Active Patients

In a prospective clinical examination of 78 knees in 60 young patients with patellofemoral pain, pain occurred frequently in the lateral peripatellar retinaculum, sometimes in association with milder, less well defined medial patellar discomfort. Patellofemoral pain in the young person is frequently a soft tissue problem initially, but aberrant mechanics (particularly lateral tracking) that cause this retinacular overuse and pain may eventually lead to synovial irritation and chondromalacia. Chondromalacia, however, may not be the primary cause of patellofemoral pain in many young people.