The influence of iliotibial tract on patellar tracking

What mechanical and proprioceptive structures are involved in quadriceps stretching? Why is it important for patella travel?

OBJECTIVE

Ely's, Ober's, and modified Thomas' tests are widely used. Stretching the front thigh involves two layers of tissue: the rectus femoris and its overlying fascia lata (FL). However, to our knowledge, no biomechanical study has analyzed these tests. Therefore, this study tries to determine the structures affected during the stretching of the front thigh.

METHODS

An observational study of the front thigh was conducted. The directions and intensities of the reaction forces were recorded. The patellar travel was used to determine the average coordinates of the stretched structures at hip level in the horizontal plane. The participants indicated the stretched area. The stretch of a patient with a complete tear of his left rectus femoris was recorded.

RESULTS

The reaction force of the thigh was oriented at 33° (standard deviation [SD]: 6°) sideways and its intensity was 60 N m (SD: 19 N m). The centroid coordinates of all stretched structures were stable. The registered average external rotational torque of 6 N m (SD: 3.7 N m) could only be mediated by the FL. The stretched area indicated by the participants could be anywhere on the FL. The tolerated reaction force increased in the same way on the disinserted rectus femoris thigh and on the uninjured thigh.

CONCLUSION

Ober's, Modified Thomas', and Ely's tests are three potential means of assessing FL extensibility. A lateral patellar tilt may be triggered by the FL's reaction force to stretching. Stretch tolerance seems to be limited by the FL, the fascia profundis of the thigh.

Effect of soft tissue tension around the knee joint on medio-lateral patellar position

Patellofemoral pain (PFP) is one of the most common sports injuries of the knee joint and has a high persistence and recurrence rate. Medio-lateral patellar position in the knee extension position during contraction is associated with PFP. However, soft tissue tension that most influences the medio-lateral patellar position in the knee extension position during contraction in vivo is unclear. We aimed to clarify the relationship between medio-lateral patellar position and soft tissue tension around the knee joint. Twelve patients with PFP and 20 healthy participants were included. Medio-lateral patellar position and tension of the rectus femoris, vastus lateralis (VL), vastus medialis, iliotibial band (ITB), lateral patellofemoral ligament, and medial patellofemoral ligament were measured during contraction and rest. The tensions of the VL and ITB during contraction and the medio-lateral patellar position at rest were significantly associated with medio-lateral patellar position during contraction (β = 0.449, 0.354, and 0.393, respectively). In addition, the tension of ITB was significantly associated with the medio-lateral patellar position at rest (β = 0.646). These relationships were not affected by the presence of PFP. These findings suggest that the patellar position during contraction became more lateral as the tension in the VL and ITB increased, regardless of the presence of PFP. These results may facilitate the prevention and treatment of PFP.

Patellar malalignment: A common disorder associated with knee pain

Pain-associated knee joint disorders are common in daily life. Practically, knee pain should be divided into the origin from the isolated tibiofemoral (TF), isolated patellofemoral (PF) joint, or a combination thereof. The TF joint controls the actions of level walking, while the PF joint controls knee flexion-extension. Owing to its sufficient inherent stability, non-traumatic disorders of the isolated TF joint in young individuals are uncommon. In contrast, because of its insufficient inherent stability, non-traumatic disorders of the isolated PF joint are common in young individuals. Patellar malalignment (PM) associated with knee pain is common in all age groups, and the most common predisposing factor is imbalanced peripatellar soft-tissue tension. The outward forces acting on the patella are caused by pulling from the quadriceps femoris during knee flexion to extension (manifested by the quadriceps angle [Q-angle]), and sliding backward of the iliotibial band (ITB) during knee extension to flexion. Once the muscle power of the vastus medialis (especially the vastus medialis obliquus [VMO]) decreases, which lowers the counteracting effect against outward forces, the patella displaces or rotates laterally. The reduced contact surface between the patella and the femoral condyle significantly increases the compressive pressure and injures the articular cartilage. Subsequently, progressive PF degeneration occurs. Although other factors may also cause PM, they are relatively uncommon. In principle, nonsurgical treatment of PM should be considered first, while surgical treatment should follow established indications. Some nonsurgical techniques are currently widely used that feature high satisfaction rates. Surgical techniques are continuously being developed, and their success rates have gradually improved. This study aimed to review the current literature for relevant studies and report related publications of the author's institution to emphasize the universality and importance of PM management. Conceptually, simply focusing on problems of the TF joint cannot treat all knee disorders.

Lower Extremity Kinetics and Kinematics in Runners with Patellofemoral Pain: A Retrospective Case–Control Study Using Musculoskeletal Simulation

Patellofemoral pain (PFP) is a common atraumatic knee pathology in runners, with a complex multifactorial aetiology influenced by sex differences. This retrospective case–control study therefore aimed to evaluate lower limb kinetics and kinematics in symptomatic and control male and female runners using musculoskeletal simulation. Lower extremity biomechanics were assessed in 40 runners with PFP (15 females and 25 males) and 40 controls (15 females and 25 males), whilst running at a self-selected velocity. Lower extremity biomechanics were explored using a musculoskeletal simulation approach. Four intergroup comparisons—(1) overall PFP vs. control; (2) male PFP vs. male control; (3) female PFP vs. female control; and (4) male PFP vs. female PFP—were undertaken using linear mixed models. The overall (stress per mile: PFP = 1047.49 and control = 812.93) and female (peak stress: PFP = 13.07 KPa/BW and control = 10.82 KPa/BW) comparisons showed increased patellofemoral joint stress indices in PFP runners. A significantly lower strike index was also shown in PFP runners in the overall (PFP = 17.75% and control = 33.57%) and female analyses (PFP = 15.49% and control = 40.20%), revealing a midfoot strike in control, and a rearfoot pattern in PFP runners. Peak rearfoot eversion and contralateral pelvic drop range of motion (ROM) were shown to be greater in PFP runners in the overall (eversion: PFP = −8.15° and control = −15.09°/pelvic drop ROM: PFP = 3.64° and control = 1.88°), male (eversion: PFP = −8.05° and control = −14.69°/pelvic drop ROM: PFP = 3.16° and control = 1.77°) and female (eversion: PFP = 8.28° and control = −15.75°/pelvic drop ROM: PFP = 3.64° and control = 1.88°) PFP runners, whilst female PFP runners (11.30°) exhibited a significantly larger peak hip adduction compared to PFP males (7.62°). The findings from this investigation highlight biomechanical differences between control and PFP runners, as well as demonstrating distinctions in PFP presentation for many parameters between sexes, highlighting potential risk factors for PFP that may be addressed through focused intervention modalities, and also the need, where appropriate, for sex-specific targeted treatment approaches.

Treatment of Proximal Trochlear Dysplasia in the Setting of Patellar Instability: An Arthroscopic Technique

Patellar instability is a complex disorder with multiple etiologies, and treatment must be individualized to the unique pathoanatomy of each patient. Medial patellofemoral ligament reconstruction is one of the most commonly performed procedures for the treatment of patellar instability. Patients with a symptomatic supratrochlear spur, defined by the presence of a "jumping" J sign on examination, also may benefit from an adjunctive proximal trochlear resection. Here, we describe a technique for an arthroscopic proximal trochlear resection, or "bumpectomy," involving resection of the supratrochlear spur. In appropriately indicated patients, we have found this procedure to be a useful adjunct to medial patellofemoral ligament reconstruction without the need for concurrent trochlear sulcus deepening.

Varied influence of the femoral or tibial component on quadriceps angles: Verified by imaging studies

Objective

The aim of this study was to evaluate the varied influence of femoral or tibial component on Quadriceps angles (Q-angle) measured with magnetic resonance image (MRI) and full-length standing scanogram (FLSS) techniques.

Methods

Two groups of patients were studied. The first group underwent MRI studies and the second group underwent FLSS studies. Two-step procedures were carried out. Knee MRI in 60 consecutive adult patients simply taken for meniscus or ligament injuries were utilized at the first step. The standardized patellar center (PC) and tibial tubercle (TT) on the frontal plane of MRI were positioned. At the second step, the FLSS in other 100 consecutive young adult patients taken for chronic unilateral lower extremity injuries were used for locating the two landmarks from MRI. The Q-angle was then determined on the anterior superior iliac spine, standardized PC, and TT on the FLSS.

Results

For 60 patients, the standardized PC was at the point 42% from the lateral end of the trans-epicondylar line of the femur. The TT was at the point 2 cm distal to the tibial articular surface and 37% from the lateral end of the tibial width. For 100 patients, the Q-angle was an average of 9.5° and 65.2% of the Q-angle was contributed by the upper arm (the femur). Women had a larger Q-angle (10.1° vs. 8.8°, p = 0.02) and a shorter femur (41.1 vs. 44.7 cm, p < 0.001).

Conclusion

The Q-angle is about 9.5° with 65.2% contributed by the femur. The Q-angle may mainly be influenced by the femoral component.

Level of evidence

Level IV, Diagnostic Study.

Patellofemoral pain in athletes

Patellofemoral pain (PFP) is a frequent cause of anterior knee pain in athletes, which affects patients with and without structural patellofemoral joint (PFJ) damage. Most younger patients do not have any structural changes to the PFJ, such as an increased Q angle and a cartilage damage. This clinical entity is known as patellofemoral pain syndrome (PFPS). Older patients usually present with signs of patellofemoral osteoarthritis (PFOA). A key factor in PFPS development is dynamic valgus of the lower extremity, which leads to lateral patellar maltracking. Causes of dynamic valgus include weak hip muscles and rearfoot eversion with pes pronatus valgus. These factors can also be observed in patients with PFOA. The available evidence suggests that patients with PFP are best managed with a tailored, multimodal, nonoperative treatment program that includes short-term pain relief with nonsteroidal anti-inflammatory drugs (NSAIDs), passive correction of patellar maltracking with medially directed tape or braces, correction of the dynamic valgus with exercise programs that target the muscles of the lower extremity, hip, and trunk, and the use of foot orthoses in patients with additional foot abnormalities.

Effects of tibial rotation on Ober's test and patellar tracking

BACKGROUND

The purpose of this study was to investigate the effects of tibial position on ITB flexibility and patellar position.

METHODS

A total of 31 asymptomatic subjects (21 males, 10 females) were recruited for this investigation. Adduction angle was measured by Ober's test, and PCD was measured by ultrasonography in three different tibial rotation conditions: N, IR, and ER.

RESULTS

Repeated measures ANOVA revealed a significant difference in adduction angle and PCD among three different tibial positions (P<0.05). Adduction angle was significantly greater in the N tibial position than in ER (P<0.05). The PCD was significantly greater in N position than in IR (P<0.05). However, the PCD was significantly smaller in IR compared with the N position (P<0.05).

CONCLUSIONS

These findings support that tibial rotation influences the flexibility of ITB and patellar positions. Therefore, excessive tibial rotation can cause inappropriate patellar positions that eventually lead to knee injury. Therapists should consider tibial rotation when measuring adduction angles because tibial rotation can change Ober's test results and contribute to the consistency of ITB length measurements.

LEVEL OF EVIDENCE

Level IV.

Sex differences in running mechanics and patellofemoral joint kinetics following an exhaustive run

Patellofemoral joint pain (PFP) is a common running-related injury that is more prevalent in females and thought to be associated with altered running mechanics. Changes in running mechanics have been observed following an exhaustive run but have not been analyzed relative to the sex bias for PFP. The purpose of this study was to test if females demonstrate unique changes in running mechanics associated with PFP following an exhaustive run. For this study, 18 females and 17 males ran to volitional exhaustion. Peak PFJ contact force and stress, PFJ contact force and stress loading rates, hip adduction excursion, and hip and knee joint frontal plane angular impulse were analyzed between females and males using separate 2 factor ANOVAs (2 (male/female)×2 (before/after exhaustion)). We observed similar changes in running mechanics among males and females over the course of the exhaustive run. Specifically, greater peak PFJ contact force loading rate (5%, P=.01), PFJ stress loading rate (5%, P<.01), hip adduction excursion (1.3°, P<.01), hip abduction angular impulse (4%, P<.01), knee abduction angular impulse (5%, P=.03), average vertical ground reaction force loading rate (10%, P<.01) and step length (2.1cm, P=.001) were observed during exhausted running. These small changes in suspected PFP pathomechanical factors may increase a runner׳s propensity for PFP. However, unique changes in female running mechanics due to exhaustion do not appear to contribute to the sex bias for PFP.

Does pelvic width influence patellar tracking? A radiological comparison between sexes

INTRODUCTION

Pelvic width has been believed to affect patellar tracking by influencing the quadriceps angle (Q-angle). Anatomically, the upper arm of the Q-angle does not closely match the orientation of the quadriceps femoris. The pelvis is often considered wider and the Q-angle larger in female than in male individuals. The purpose of this retrospective study was to investigate the accuracy of such an assumption by using a radiologic comparison, which might be more objective.

MATERIALS AND METHODS

One hundred consecutive adult patients (50 men and 50 women) aged 18-30 years with unilateral injury to the lower extremity were studied. Full-length standing X-rays of these patients was used to analyze the relationship between the pelvis and the uninjured lower extremity and compare it between the sexes. The pelvic width was defined as the distance between the centers of the bilateral femoral heads.

RESULTS

The pelvic width did not differ statistically between male and female (P=0.74). The femur length and sum of the lengths of the femur and tibia differed between the sexes (both P<0.001). Normalization of the pelvic width to the femur length or sum of the lengths of the femur and tibia resulted in a significant difference between male and female (P<0.001). The angle formed by the femoral and tibial mechanical axes correlated strongly with the angle formed by the femoral anatomic and tibial mechanical axes (Pearson correlation coefficient=0.89).

DISCUSSION

Pelvic width does not differ with respect to gender. The pelvis may appear relatively wider in women due to the difference in body height. However, this difference may not increase Q-angle. Patellar mal-tracking may stem from other, more critical predisposing factors.

LEVEL OF EVIDENCE

Level IV. Anatomic study.

Increased medial foot loading during drop jump in subjects with patellofemoral pain

PURPOSE

To compare medial-to-lateral plantar forces during drop jump and single leg squat in individuals with and without patellofemoral pain.

METHODS

This cross-sectional study compared 23 young adults with patellofemoral pain to 20 age- and sex-matched controls without knee pain. The plantar pressure distribution was collected during drop jump and single leg squat using pressure-sensitive Pedar insoles, inserted into a standard flat shoe. The primary outcome was the medial-to-lateral force, quantified as the peak force under the medial forefoot as the percentage of force under the total forefoot during drop jump. Secondary outcomes included peak medial-to-lateral force during single leg squat and mean forces during drop jump and single leg squat.

RESULTS

The primary outcome showed that individuals with patellofemoral pain had a 22% higher medial-to-lateral peak force during drop jump, (p=0.03). Secondary outcomes showed 32% higher medial-to-lateral peak force during single leg squat (p=0.01) and 19-23% higher medial-to-lateral mean force during drop jump and single leg squat (p=0.02-0.04).

CONCLUSION

These findings indicate that individuals with patellofemoral pain display a more medially oriented loading pattern of the forefoot compared to individuals without knee pain. This loading pattern may be associated with the distribution of forces acting on the patellofemoral joint and suggest treatment of PFP should consider interventions that target normalisation of foot loading.

LEVEL OF EVIDENCE

III.

Patellofemoral pain syndrome

The patellofemoral pain syndrome (PFPS) is a possible cause for anterior knee pain, which predominantly affects young female patients without any structural changes such as increased Q-angle or significant chondral damage. This literature review has shown that PFPS development is probably multifactorial with various functional disorders of the lower extremity. Biomechanical studies described patellar maltracking and dynamic valgus in PFPS patients (functional malalignment). Causes for the dynamic valgus may be decreased strength of the hip abductors or abnormal rear-foot eversion with pes pronatus valgus. PFPS is further associated with vastus medialis/vastus lateralis dysbalance, hamstring tightness or iliotibial tract tightness. The literature provides evidence for a multimodal non-operative therapy concept with short-term use of NSAIDs, short-term use of a medially directed tape and exercise programmes with the inclusion of the lower extremity, and hip and trunk muscles. There is also evidence for the use of patellar braces and foot orthosis. A randomized controlled trial has shown that arthroscopy is not the treatment of choice for treatment of PFPS without any structural changes. Patients with anterior knee pain have to be examined carefully with regard to functional causes for a PFPS. The treatment of PFPS patients is non-operative and should address the functional causes.

LEVEL OF EVIDENCE

V.

The effect of hip adduction angle on patellar position measured using real time ultrasound scanning

INTRODUCTION

There are limited in vivo studies investigating the influence of the Iliotibial Band (ITB) on patellar position, despite numerous references in the literature to this relationship. The purpose of this study was to investigate how the ITB influences patellar position, in vivo, indirectly through alteration of frontal plane hip position.

METHOD

Twelve healthy, asymptomatic, male subjects (age 23 ± 2.6 years) had their patellar position examined using real time ultrasound scanning. The knee was passively placed into 20° flexion and combined with hip neutral, 20° hip adduction and 20° hip abduction. Mean patellar position (distance from the lateral border of the patella to the edge of the intersection of the trochlear groove and lateral femoral condyle) was measured, with the smaller values representing a position whereby the patella is drawn more laterally and closer to the lateral femoral condyle.

RESULTS

Mean patellar position for neutral was 8.1mm (± 1.72 mm). Following 20° hip abduction the mean patellar position was 8.9 mm (± 1.7 9 mm), this was a statistically significant change in patellar position (p=0.003). Following 20° hip adduction the mean patellar displacement was 7.3mm (± 1.4mm) which, again, was a statistically significant change in patellar position (p=0.009). The results indicate that with the hip adduction the patella was positioned significantly more laterally (smaller value for distance).

DISCUSSION

The results of this study support the hypothesis that hip adduction which is likely to create loading and lengthening of the ITB causes significantly greater lateral displacement of the patella, than when the hip is abducted and the ITB unloaded.

Iliotibial band release as an adjunct to the surgical management of patellar stress fracture in the athlete: a case report and review of the literature

Stress fracture of the patella is rare. In this report, a case of patellar stress fracture occurring in an amateur athlete is presented, and an operative adjunct to the surgical management of this condition is proposed.

A review of the English literature identified 21 previous cases of stress fracture of the patella, the majority in young athletes. None of these reports discussed treatment addressing the pathological process contributing to patellar stress fracture.

The subject of this case report is a young male netballer who presented with a transverse stress fracture in the inferior third of his patella, on a background of patellofemoral overload. The patient underwent open reduction and internal fixation of his patella, combined with release of the iliotibial band. He returned to training after 6 weeks.

The previous literature suggests that operative fixation is indicated for the treatment of displaced patellar stress fractures. Iliotibial band release, as a surgical adjunct to this treatment, may address the pathology of these fractures, and facilitate a return to sport at the highest level.

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Iliotibial band tension reduces patellar lateral stability

This study investigated the effect of loading the iliotibial band (ITB) on the stability of the patellofemoral joint. We measured the restraining force required to displace the patella 10 mm medially and laterally (defined as medial and lateral stability, respectively) in 14 fresh-frozen knees from 0 to 90 degrees knee flexion. The testing rig allowed the patella to rotate and translate freely during this displacement. The quadriceps was separated into five components and loaded with 175 N total tension. Testing was performed at 0 to 90 N ITB tension. With no ITB tension, the lateral restraining force ranged from 82 to 101 N across 0 to 90 degrees flexion. Increasing ITB tension caused progressive reduction of the lateral restraining force. The maximum reduction was 25% at 60 degrees flexion and 90 N ITB tension. Medial restraining force increased progressively with increasing knee flexion and increasing ITB loads; it ranged from 74 N at 0 degrees knee flexion and 0 N ITB tension to 211 N at 90 degrees knee flexion and 90 N ITB tension. The maximum effect was an increase of medial restraining force of 50% at 90 degrees flexion and 90 N ITB tension.

Lower extremity jumping mechanics of female athletes with and without patellofemoral pain before and after exertion

BACKGROUND

Patellofemoral pain is especially common among female athletes and is traditionally associated with lower extremity mechanics thought to increase retropatellar stress. These detrimental mechanics may increase with exertion.

HYPOTHESIS

Differences in lower extremity mechanics during single-legged jumps between female athletes with and without patellofemoral pain will increase after exertion.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty women with patellofemoral pain and 20 healthy female controls participated in a functional lower extremity exertion protocol of repetitive single-legged jumps. Pain, exertion, hip and trunk strength, and 3-dimensional lower extremity joint mechanics were recorded at the beginning and end of the protocol.

RESULTS

The patellofemoral pain group reported increased pain at the conclusion of the protocol. However, all subjects terminated the protocol due to complaints of fatigue. Mean strength measurements for the patellofemoral pain group were 24% lower for lateral trunk flexion (P = .06), 13% lower for hip abduction (P = .09), and 14% lower for hip external rotation (P = .03) than for controls. Subjects with patellofemoral pain demonstrated greater contralateral pelvic drop at the end of the exertion protocol compared with the control group (P = .003). Group differences in lower extremity mechanics, including increased hip adduction angle, hip flexion angle, hip abduction angular impulse, and decreased hip internal rotation angles, were observed among women with patellofemoral pain throughout the exertion protocol. These group differences were consistent despite increased pain for the patellofemoral pain group after exertion. Both groups demonstrated decreased jump height, hip flexion and internal rotation, knee flexion, and hip extension impulse at the end of the protocol.

CONCLUSION

Women with patellofemoral pain demonstrated lower extremity mechanics that differed from the healthy control group during single-legged jumping, particularly at the hip. These differences do not appear to vary with exertion level or pain among patellofemoral pain subjects during single-legged jumps.

CLINICAL RELEVANCE

Lower extremity jumping mechanics appear to be consistently different among women with patellofemoral pain. Conservative treatment programs that include kinematic retraining as well as hip and trunk strengthening may improve patient outcomes and prevent recurrence of this common orthopaedic condition.

Anatomy of the lateral retinaculum of the knee

Anatomical descriptions of the lateral retinaculum have been published, but the attachments, name or even existence of its tissue bands and layers are ill-defined. We have examined 35 specimens of the knee. The deep fascia is the most superficial layer and the joint capsule is the deepest. The intermediate layer is the most substantial and consists of derivatives of the iliotibial band and the quadriceps aponeurosis. The longitudinal fibres of the iliotibial band merge with those of the quadriceps aponeurosis adjacent to the patella. These longitudinal fibres are reinforced by superficial arciform fibres and on the deep aspect by transverse fibres of the iliotibial band. The latter are dense and provide attachment of the iliotibial band to the patella and the tendon of vastus lateralis obliquus.

Our study identifies two important new findings which are a constant connection of the deep fascia to the quadriceps tendon superior and lateral to the patella, and, a connection of the deeper transverse fibres to the tendon of vastus lateralis obliquus.

Lower extremity mechanics of females with and without patellofemoral pain across activities with progressively greater task demands

BACKGROUND

Patellofemoral pain is commonly associated with lower extremity joint rotations that decrease retropatellar contact area and subsequently increase retropatellar stress during weightbearing activities. People with patellofemoral pain are thought to be capable of avoiding such harmful mechanics during activities with low external demands. However, this may not be possible during more demanding activities. The purpose of this study was to analyze lower extremity mechanics in females with and without patellofemoral pain during three different activities. Specifically, we sought to determine if differences between groups increase with increasingly demanding activities.

METHODS

20 females with patellofemoral pain and 20 healthy female controls performed single leg squats, running, and repetitive single leg jumps as their three-dimensional lower extremity mechanics were recorded. Transverse and frontal plane hip and knee kinematics were compared between groups for all activities.

FINDINGS

Differences in the variables of interest between groups did not generally depend on the nature of the activity. The patellofemoral pain group performed all three activities with 4.3 degrees greater knee external rotation (P=0.06), 3.5 degrees greater hip adduction (P=0.012), and 3.9 degrees decreased hip internal rotation with respect to the control group (P=0.01).

INTERPRETATION

These results suggest that females with patellofemoral pain do not employ different mechanics as demand of the activity increases. Rather, females with patellofemoral pain seem to demonstrate similar abnormal lower extremity mechanics across a variety of activities.