patellofemoral pain syndrome - turner white · pdf filepateoemora ain syndrome orthopaedic...

6 Hospital Physician Board Review Manual www.turner-white.com

OrthOpaedic Surgery BOard review Manual

Statement of editorial PurPoSe

The Hospital Physician Orthopaedic Surgery Board Review Manual is a study guide for trainees and practicing physicians preparing for board examinations in orthopaedic surgery. Each manual reviews a topic essential to the current practice of orthopaedic surgery.

PuBliSHinG Staff

PRESIDENT, GRouP PuBLISHERBruce M. White

SENIoR EDIToRRobert Litchkofski

ExEcuTIvE vIcE PRESIDENTBarbara T. White

ExEcuTIvE DIREcToR of oPERaTIoNS

Jean M. Gaul

NoTE fRoM THE PuBLISHER:This publication has been developed without involvement of or review by the American Board of Orthopaedic Surgery.

Patellofemoral Pain SyndromeSeries Editor:Pedro K. Beredjiklian, MDAssociate Professor of Orthopaedic Surgery, Thomas Jefferson University Hospital, Philadelphia, PA; Chief, Division of Hand Surgery, The Rothman Institute, Philadelphia, PA

Contributors:Barry Kenneally, MDAssistant Professor of Nonsurgical Sports Medicine, Thomas Jefferson University, Rothman Institute, Philadelphia, PA

Michael Ross, MDSports Medicine Physician, The Rothman Institute, Philadelphia, PA

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Patellofemoral Mechanics . . . . . . . . . . . . . . . . . .7 Evaluation and Diagnosis . . . . . . . . . . . . . . . . . . .8 Treatment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Table of Contents

P a t e l l o f e m o r a l P a i n S y n d r o m e

www.turner-white.com Orthopaedic Surgery Volume 8, Part 6 7

ORTHOPAEDIC SuRgERy BOARD REvIEw MAnuAl

Patellofemoral Pain SyndromeBarry Kenneally, MD, and Michael Ross, MD

introduction

Patellofemoral pain syndrome (PFPS) is a dis-order of the patellofemoral joint in which abnormal tracking of the patella through the femoral groove is often cited as the culprit. The result of the mal-tracking is pain and retropatellar cartilage loss. The etiology of patellofemoral pain is multifactorial, making examination and treatment difficult.

Patellofemoral pain accounts for 25% of knee injuries in the general population and may be responsible for an even higher proportion in ath-letes.1,2 In a retrospective study that explored the natural history of patellofemoral pain in athletes, running contributed to one-third of cases.1 This injury is seen more commonly in women and oc-curs predominately in athletes under age 25 years. Despite the common nature of the problem, only approximately one-quarter of patients improve with conservative therapy.1

Patellofemoral mecHanicS

anatOMy and nOrMal FunctiOn

The knee joint is a hinge joint with a sesamoid bone (patella) interposed between the quadriceps and patella tendons. As the quadriceps muscles

contract, the patella acts as a pulley to move the lower leg. The patella moves along the intercon-dylar groove in the distal femur during knee flex-ion and extension. Patellar tracking relies upon the bony contours of the distal femur and on the muscles and retinaculae around the patellofemoral joint.

The patella contains the thickest layer of carti-lage in the body. The patella improves knee flexion by acting as a frictionless pulley for the quadriceps tendon and by keeping it off the anterior joint. In doing this, it also serves as a joint tensioner and a guide for the patellar tendon. The patella has 5 facets: medial, lateral, superior, inferior, and odd. The odd facet is usually the first area affected in patellofemoral pain.3 As the knee is flexed and extended, different facets articulate with the femo-ral condyles. At 20 degrees of flexion, the inferior facet is the first to make contact, followed by the medial and lateral (45 degrees), the superior (90 degrees), and finally the odd facet (135 degrees).

Quadriceps muscle forces play a major role in medial-lateral forces, contact forces,4 and pressure distribution of the patellofemoral joint. The vastus medialis obliquus (VMO) has been thought to limit lateral movement and tilt of the patella. Decreased strength of the VMO leading to an imbalance

copyright 2012, Turner White communications, Inc., Strafford avenue, Suite 220, Wayne, Pa 19087-3391, www.turner-white.com. all rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, mechanical, electronic, photocopying, recording, or otherwise, without the prior written permission of Turner White communications. The preparation and distribution of this publication are supported by sponsorship subject to written agreements that stipu-late and ensure the editorial independence of Turner White communications. Turner White communications retains full control over the design and production of all published materials, including selection of topics and preparation of editorial content. The authors are solely responsible for substantive content. Statements expressed reflect the views of the authors and not necessarily the opinions or policies of Turner White communications. Turner White communications accepts no responsibility for statements made by authors and will not be liable for any errors of omission or inaccuracies. Information contained within this publication should not be used as a substitute for clinical judgment.



between VMO and vastus lateralis forces while walking/running has traditionally been considered a major causative factor of PFPS. However, the pro-posed mechanism for VMO weakness as a cause of patellofemoral pain is coming into question, as a recent study found no difference in the muscle forces from the VMO and vastus lateralis during walking and running in patients with patellofemoral joint pain versus pain-free controls.5 As the knee is flexed to 20 degrees, the patella articulates with the femoral groove and the articulation is strength-ened by the vastus lateralis. If unopposed, there is lateral patellar translation.6 Beyond 60 degrees of flexion, there is increased pressure across the joint and on the patellofemoral joint.

altered BiOMechanicS

Proximal to the knee, the hip, pelvis, and trunk can affect knee mechanics in multiple planes.7,8

Women seem to be more susceptible to proximal weakness. Gluteus minimus and medius weak-ness is responsible for frontal plane motion (knee valgus) and joint stress. The excess motion can lead to patellofemoral joint pain, and this effect is magnified when the muscles are fatigued.9 When this altered motion is observed, interventions to increase neuromuscular control of the gluteal muscles can improve outcomes.10 Studies have demonstrated that in patients with PFPS the glu-teus medius is weaker, with both delayed onset and shorter activation duration.11,12 These patients also have decreased eccentric strength in the hip abductors; correcting this eccentric weakness is an important part of therapy.13,14

Hamstring length is decreased in PFPS pa-tients compared with controls, although this may be a result of the syndrome rather than a cause of it.15 As noted, there is some controversy sur-rounding the role of VMO strength in PFPS. There

is evidence that delayed activation rather than weakness of VMO may lead to PFPS.16 Addition-ally, the increased tonicity of the vastus lateralis seems to overpower the VMO in PFPS patients.17

Moreover, the role of another medial muscle is being investigated: namely, the adductor longus has been shown to have longer activation dura-tion during stair climbing in patients with patel-lofemoral pain.18 This would alter biomechanics in the frontal plane, leading to knee valgus and lateral instability.

Looking distal to the affected knee, foot posture may also play a role in PFPS. Foot overpronation causes excessive internal tibial rotation, which results in a relative lateral movement of the patel-la.19,20 Overpronation also leads to earlier rearfoot eversion, which may be associated with patel-lofemoral pain.21 Other gait changes associated with patellofemoral pain include increased rearfoot eversion at heel strike, greater knee external rota-tion, and greater hip adduction.22 More recently, it has been shown that PFPS likely results from in-creased medial femoral rotation rather than lateral patellar rotation.23

evaluation and diaGnoSiS

phySical exaMinatiOn

The examination for PFPS is directed toward finding underlying ligamentous laxity, biomechani-cal abnormalities, and muscle weaknesses. No single gold standard test has been validated by the literature.24 Many common tests have not been evaluated or have low reliability. Physical exami-nation findings most often correlated with PFPS include an abnormal Q-angle, generalized liga-mentous laxity, hypomobile or hypermobile patella, tenderness of the lateral patellar retinaculum, pa-tellar tilt or medial/lateral displacement, decreased



flexibility of the iliotibial band and quadriceps, and weakness of the quadriceps, hip abductors, and external rotators.24

Q-angleMuch attention has been paid to the Q-angle

and its role in patellofemoral pain. The Q-angle is defined as the angle between 2 lines, the first drawn from the anterior superior iliac spine to the midpoint of the patella, and the second drawn from the midpoint of the patella to the tibial tubercle. These measurements are made when the patient is supine with the quadriceps relaxed. A large Q-angle (≥15–20 degrees) has been thought to be responsible for anterior knee pain.25 The traditional thinking has been that as the Q-angle increases, so does knee valgus, which increases the likeli-hood of the patella to sublux laterally. The clinical utility of the Q-angle for predicting patellofemoral subluxation and displacement is limited due to lack of distinct correlation with PFPS.26,27 An increased Q-angle has also been shown to correlate with medial displacement.28

J-SignThe J-sign refers to the inverted J-shaped path

the patella makes in terminal knee extension in cases where maltracking is present. The exam is performed with the patient sitting and extending the knee.24 In patients with a positive test, as the knee is extended, the patella initially tracks along the axis of the intercondylar groove but takes a lateral path at terminal extension. The presence of a J-sign likely represents a ligamentous problem or a lateral inclination of the trochlea.29

lateral hypermobility The lateral patellar glide test assesses for lateral

hypermobility and is performed with the patient

supine. The examiner applies a lateral force to the patella and assesses if there is excess mobility. Normal patella movement is when the patella can be displaced up to one half of its width, both me-dially and laterally. Lateral hypermobility leads to more lateral displacement of the patella.28

clarke SignTo perform this test, the patient is positioned su-

pine on the exam table and the examiner applies pressure over the superior pole of the patella while the patient pushes the back of the knee into the exam table. A positive test will elicit pain and inhibit quadriceps contraction. A negative test is pain free and contraction can be maintained. The test can be repeated with the knee flexed to 30, 60, and 90 degrees to elicit pain in different retropatellar fac-ets. A positive test helps to localize the retropatellar facets as the source of the pain.

patellar tilt testThis test is performed with the patient in the

supine position with the knee extended and the quadriceps relaxed. While leaving the patella in the intercondylar groove, the patella is tilted away from the lateral femoral condyle. If the lateral patella lifts less than 15 degrees (10 degrees in males) beyond the horizontal plane, the patient is prone to PFPS. There is large variability among examiners with this test.30

Ober testAlthough the Ober test is used to measure ilio-

tibial band flexibility, it also is correlated with patel-lofemoral pain. With the patient in the side lying position with the affected side up and the lower leg flexed at the hip and knee, the examiner stabilizes the pelvis and abducts and extends the affected leg at the hip while the knee is flexed. The exam-



iner then lowers the hip into adduction. If there is iliotibial band tightness, the leg does not fall to the table (remains in abducted position).

diagnOStic iMaging

The diagnosis of PFPS depends mainly on the history and physical exam. Imaging is not neces-sary to make the diagnosis but can be helpful to assess patellofemoral alignment and to rule out other problems such as loose bodies, patellofemo-ral osteoarthritis, and occult fracture. Radiographs should certainly be obtained in a patient who has no response to several weeks of treatment.

An axial or Merchant view with the knee flexed to 30 degrees can yield important information re-

garding the patellofemoral joint. Axial views can demonstrate patellofemoral osteoarthritis, dyspla-sia of the trochlea, retinacular calcifications, ac-cessory ossification centers, osteochondritis, and patellar morphology. The axial view can also help to assess patellar alignment. It is with this view that we can calculate patellar tilt, sulcus angle, and congruence angle. In addition, the lateral view can be used to diagnose trochlear dysplasia. The most important sign of dysplasia on the lateral view is crossing sign (Figure 1).

The sulcus angle is the angle of the femoral trochlea (angle ML in Figure 2). The trochlear groove provides stability for the patella, and thus a shallow angle is associated with subluxation. Al-

Figure 1. Crossing sign in trochlear dysplasia. (a) A normal lateral radiograph, in which the line representing the floor of the femoral trochlea (arrow) turns within the femoral condyle and travels proximally to terminate within the femoral shaft. (B) Lateral radiograph illus-trating the positive crossing sign. The line representing the floor of the trochlea (arrow) terminates within the femoral condyles, indicating a shallow trochlea.



though a steep trochlea does not lead to instability, it can cause pain. The average sulcus angle is 140 degrees.31

The congruence angle is a measure of medial and lateral subluxation of the patella (Figure 2). This is the radiographic version of the patellar glide test on physical examination. The average congru-ence angle is –6 degrees in nondislocators, with a standard deviation of 11 degrees. In Figure 2, angle ML is the sulcus angle and line A bisects this angle. Line C passes from the nadir of the trochlea through the lowest point of the median patellar ridge. Angle CA is the congruence angle. The angle is expressed in positive degrees if line C is on the lateral side of line A.31

Patellar tilt measures the tilt of the patella within the trochlea. The patellar tilt angle is formed by a horizontal line and a line drawn between the medial and lateral corners of the patella (Figure 3). This angle usually opens laterally, with normal being 0 to 5 degrees. Patellar tilt above 10 degrees is strongly associated with PFPS.32

Patella alta and patella baja are both associ-ated with PFPS. They can easily be assessed on a lateral radiograph of the flexed knee. There are several ways to calculate patellar height, but one of the easiest and most widely used is to compare patellar articular length (not the entire length of the patella) to the distance between the inferior pole of the patella and the tibial plateau (Figure 4).33 The values should be about equal. The ratio of A to B should be 0.8:1.0. In patella alta the ratio is >1.0 and in patella baja it is <0.8. The lateral view may also demonstrate signs of trochlear dysplasia such as crossing sign, double contour, and a su-pratrochlear spur.

Magnetic resonance imaging (MRI) should be considered in PFPS if there is an effusion or a poor response to several weeks of therapy. MRI or computed tomography should also be considered if surgery is contemplated. MRI may show evidence

Figure 2. Sulcus angle (angle ML) and congruence angle (angle CA). (Adapted from Christian SR, Anderson MB, Workman R, et al. Imaging in anterior knee pain. Clin Sports Med 2006;25:681–702.)

Figure 3. Patellar tilt angle. (Adapted with permission from Grel-samer RP, Bazos AN, Proctor CS. Radiographic analysis of pa-tellar tilt. J Bone Joint Surg Br 1993;75:823.)

Medial lateral

α

M l

ca



of chondromalacia, loose bodies, synovial plica, or true dislocation. The presence of any one of these would lead to different types of treatment. Loose bodies and plicae may be amenable to arthroscopy. Chondromalacia would prompt treatment for de-generative disease such as viscosupplementation. Recurrent dislocation may prompt treatment with patellar realignment.

treatment

When treating PFPS, it is important to assess not only the knee biomechanics of patients, but

also hip and foot biomechanics. When doing so, both dynamic and static alignment should be as-sessed. Simple gait analysis in the office can be helpful in this regard. By taking all of the biome-chanical factors into account, a more appropriate treatment regimen can be formulated.

nOnSurgical

Physical therapy is the mainstay of treatment for PFPS. It may be used alone or in conjunction with other modalities. Other nonsurgical treatments include McConnell taping, patellar tracking braces, and foot orthotics. These secondary modalities are often used for treatment at the time of diagnosis, but many reserve them for failures of treatment with physical therapy.

physical therapyPFPS treatment accounts for 10% to 25% of

all physical therapy visits.34 Physical therapy has been shown to be cost effective in the treatment of PFPS.35 Although the effects of physical in-terventions on outcomes in PFPS patients have been investigated extensively, with many studies showing positive outcomes, overall results have been mixed and treatment regimens quite varied. These studies are fraught with difficulty for a num-ber of reasons. Physical therapy interventions cannot be blinded like other treatments. Also, these studies have focused on different targets, often with different methodologies (ie, closed versus open chain exercises). Some studies use dynamometers to test strength and muscle function, others use electromyography (EMG), and still others use simple observation. As such, there is a need for larger clinical trials using very focused treatments on appropriately chosen sub-jects. Use of self-reported pain scales, such as a visual analog scale, to assess treatment effec-

Figure 4. Patella alta and patella baja measurement. Length of the patella (B) should be nearly equal to the distance between the inferior pole of the patella and the tibial plateau (a). The ratio of A:B should be 0.8:1.0. (Adapted with permission from Black-burne JS, Peel TE. A new method of measuring patellar height. J Bone Joint Surg Br 1977;59:241.)

a

B



tiveness is very important as pain is the present-ing complaint. New technologies that allow for elaborate functional assessments include video gait analysis, dynamic MRI, EMG, and electronic movement sensors.

Quadriceps weakness. Physical therapy tra-ditionally focuses on the quadriceps muscles, as this is the muscle group that exerts the most influence on the patella. Since muscle is more plastic than other tissues, it is amenable to physi-cal therapy interventions. As discussed, relative weakness of the VMO can cause lateral patellar tracking, leading to anterior knee pain, and there is some evidence that PFPS patients have either delayed or shortened VMO activation during ac-tivity.18 Improving quadriceps strength and func-tion can go a long way toward relieving anterior knee pain.36 In fact, 1 study showed a dramatic improvement in anterior knee pain using 1 simple VMO strengthening exercise, a modified leg raise.37

Most practitioners believe that quadriceps strengthening should be a part of the treatment for PFPS, but there are many ways to achieve this. Closed kinetic chain quadriceps strength-ening exercises are generally preferred to open kinetic chain exercises, as open chain exer-cises increase stress on the patellofemoral joint. Double leg squat with isometric hip adduction (wall squat while squeezing a pillow between the knees) produces significant activation of the VMO as measured by EMG.38,39 However, open chain exercises should have some role in PFPS reha-bilitation since they help to achieve strengthening throughout the entire arc of knee motion. Also, open chain exercises may better approximate an athlete’s competitive activities. The use of elec-trical stimulation of the quadriceps in physical therapy is an adjunctive treatment to consider; it

has been shown to increase the force created by the VMO.40

Knee and hip tightness. Although quadri-ceps strengthening is an important part of treat-ment, PFPS should be approached with a com-prehensive rehabilitation program. Simple VMO strengthening is not always enough to eliminate anterior knee pain, as studies show mixed results with VMO strengthening alone,41 and strengthen-ing alone is not always enough to overcome tight-ness in opposing tissues. Thus, stretching should be incorporated into a physical therapy regimen for PFPS. Targets in physical therapy include stretching of a tight lateral patellar retinaculum, hamstring stretching, plantar flexor stretching, hip strengthening and stretching, core stabilization, and gait retraining. Several studies have demon-strated improved pain and function after treatment with hip strengthening, stretching, and balancing exercises.42–44 Again, it is difficult to measure which part of the treatment yielded the most ben-efit. More focused studies might be helpful in this regard.

excessive hip internal rotation. Abnormal hip mechanics are an important factor in PFPS, espe-cially in women.45 To understand this, it is impor-tant to picture what happens to the patella when the hip goes through moves in certain directions. Excessive internal rotation of the hip and excessive hip adduction place the patella in a lateral posi-tion in the femoral trochlea. Excessive hip adduc-tion can also increase the Q-angle. If hip internal rotation is present throughout the gait cycle, this may be due to femoral anteversion, a fixed bone deformity that is poorly responsive to physical therapy. However, if the hip internally rotates only during parts of the gait cycle, this can be caused by weakness in the hip flexors or external rotators. Weak hip flexors can also lead to an anterior pelvic



tilt, which contributes to femoral internal rotation. The primary hip flexor is the iliopsoas, although it is a secondary external rotator as well. The glu-teus muscles are the primary hip external rotators. Thus, core strengthening should also be a part of the treatment for PFPS.

gait imbalance. Gait retraining is another physi-cal therapy methodology that has been found use-ful in PFPS.46 Gait retraining involves in-depth gait analysis, which can be done by simply observing patients running or walking on a treadmill. More advanced techniques use sensors and video to provide patients with real-time visual feedback on their gait, allowing them to make adjustments. Unfortunately, this form of gait retraining is not practical on a wide scale. However, one study using simple goosestep training achieved pain reduction without the need for high-tech equip-ment.47 This study also showed improvement in congruence angles and VMO/vastus lateralis strength ratio after 1 month of treatment.

Overtraining. Since PFPS is often an overuse syndrome, prevention is important. In a recent study, preventive physical therapy was found to reduce the incidence of anterior knee pain by 75% in military recruits.48 This information may be especially useful for team physicians. It is also im-portant to guide patients when they are starting a new exercise regimen or increasing their volume of exercise. In general, it is best to increase exercise volume by no more than 10% per week.

psychological aspects. Aside from all of the biomechanical aspects of PFPS, there is also a psychological component. Recent research has shown that fear-avoidance beliefs can play a strong role in PFPS.49 Fear-avoidance behavior is more often observed in patients with back pain, where patients avoid activity for fear of causing pain or damage. Similarly, some patients with

PFPS will avoid exercise out of fear of causing harm. Patients with fear-avoidance behaviors tend to have personality traits marked by avoid-ing problems rather than confronting them. It is important to teach patients with these behaviors the difference between hurt and harm, which can help them avoid overprotection and return to regular activities.

OrthoticsFoot orthoses have been widely used in the treat-

ment of PFPS. Orthoses are used to correct foot overpronation, which is thought to lead to PFPS by causing tibial internal rotation. This in turn leads to increases in femoral internal rotation, hip adduc-tion, and dynamic Q-angle. Recent studies have shown that orthoses can reduce pain in PFPS.50,51

However, studies have typically shown mixed re-sults. Given that PFPS is a multifactorial condition, it stands to reason that studies of individual inter-ventions would have mixed results. There are also a number of different orthotic devices available that may have varying effects. These include full, par-tial, and custom insoles. As with physical therapy modalities, it is important to select which patients will benefit from orthoses. Recent studies have suggested that dynamic measurements of prona-tion can more accurately identify patients who will benefit from orthotic devices.51,52 One of these studies also found that pronation relative to the floor was more predictive than pronation relative to the tibia.51 However, overpronation is not the only foot problem that can lead to PFPS. In a prospec-tive gait study of military recruits, it was found that recruits with less pronation were the most likely to develop PFPS.53 In summary, foot orthoses may be helpful in PFPS patients with overpronation, but it would be unwise to treat all PFPS patients with orthotic devices.



Mcconnell tapingMcConnell was the first to describe patellar tap-

ing as a treatment for PFPS (Figure 5).54 The ra-tionale for taping is to move the patella into proper alignment, typically to produce a medial stress on the patella, thus correcting lateral displacement. However, some therapists and athletic trainers use taping to correct medial or superior displacement. Taping is easy and convenient to use, but studies on its effectiveness have been mixed.

McConnell found that taping reduces pain, cor-rects abnormal patellofemoral alignment, and fa-cilitates VMO activation.54 Follow-up studies have been mixed, and it has been especially difficult to prove that taping helps with VMO function. A recent study using EMG found no improvement in VMO activation and also found some loss of VMO strength in fatigued subjects.55 However, patellar taping may help to correct alignment problems. A study using dynamic MRI showed that taping helped to correct medial or lateral patellar displace-ment.56 This study also showed that McConnell taping caused an inferior patellar shift. Patella alta is associated with PFPS, and an inferior patel-lar shift would create more contact between the patella and femur, theoretically resulting in more stability and less pain.

Taping has been shown to reduce reaction forces within the patellofemoral joint.57 A recent study showed that taping reduced pain in PFPS, but it was less effective in patients with high BMI, larger lateral patellar angles, and smaller Q-angles.58 Again, it is important to take individual biomechanics into account when treating PFPS. To get the best results with McConnell taping, many therapists will assess a patient’s biome-chanics and then try a few taping techniques to find which is the most comfortable. Many thera-pists will especially use taping during early treat-

ment sessions when patients sometimes cannot perform certain exercises due to pain. If taping is effective, the technique can easily be taught to the patient.

Knee BracesKnee braces in PFPS attempt to achieve patel-

lar stabilization in much the same manner as Mc-Connell taping. Braces have the benefit of being easier to use, but they are also more expensive and less versatile. The traditional brace for PFPS is the J-sleeve, which has a J-shaped pad along the lateral and inferior aspects of the patella. This brace can be helpful with lateral subluxation but cannot be customized as well as taping. How-ever, some braces allow patients to adjust the J-pad since it is held in place by Velcro. Studies have shown that bracing alone can be helpful in PFPS but add little when combined with physical therapy.59,60

Figure 5. McConnell taping.



Surgery

Surgery should be considered for PFPS only after all other treatments have failed and only if the pain is severe and debilitating. It is more com-mon to operate when PFPS is associated with repetitive patellar dislocation. Similar procedures have been performed to treat both problems. In patients with a poor response to conservative management, it is important to obtain an MRI to rule out cartilage lesions in the patellofemoral compartment. Surgical treatment is unlikely to be of benefit unless there is a specific structural ab-normality to address.

Since the etiology of PFPS is multifactorial, many surgical procedures have been used to treat it. These include lateral retinacular lengthening, medial retinacular tightening, arthroscopic carti-lage debridement, resection of inflamed or scarred plicae, shaving of excessive inflamed synovium, and tibial osteotomy to reposition the insertion of the patellar tendon. Choosing the right patient and the right techniques is critical. Advanced imaging such as MRI and CT can help a great deal in this respect. MRI has the advantage of being safer and better at showing soft tissues, but CT is better for showing bone alignment and deformity, especially with 3-D reconstruction.

Osteochondral lesionsOsteochondral (OCD) lesions of the femur and

patella can cause anterior knee pain and may be amenable to surgery. Surgery may be especially helpful if there is a flap of cartilage causing pain or mechanical symptoms. OCD lesions of the femur can also be treated with microfracture or osteoar-ticular transfer system (OATS) procedures. Other problems which can be addressed at the time of surgery are removal of scarred plica and inflamed synovium. When considering such a procedure, it

is important to consider other possible sources of pain and to explain to the patient the possibility of residual pain after surgery.

One randomized controlled trial compared ar-throscopy plus an 8-week home exercise program with the exercise program alone.61 Procedures done at arthroscopy consisted of debridement of chondral lesions, resection of inflamed or scarred medial plicae, and shaving of excessive and in-flamed synovium. At short- and long-term follow-up (5 years), there was no difference between the groups. Both groups showed improvement in their pain scores, as assessed by visual analog scales. This study showed no benefit to arthroscopy, but the procedures used did not directly address knee alignment.

excessive patellar tiltExcessive patellar tilt causes overload of the

lateral patellar facet. This is addressed surgically with a release of the lateral patellar retinaculum. The most common surgical procedure performed for PFPS is a lateral retinacular release (Figure 6 and Figure 7). Standard lateral release involves transecting the inferior third of the vastus lateralis tendon as well as the epicondylopatellar band. In an extended release, the patellotibial band is also transected. The extended release results in sig-nificantly more medial displacement. Lateral reti-nacular release and lengthening have been shown to improve pain scores in patients with PFPS, but patient satisfaction ranges from 14% to 100% in various studies.62 Results tend to be better when postoperative Merchant view x-rays show reloca-tion of the patella. However, even if realignment is achieved, patients often continue to have pain and functional disability. Women traditionally have a poorer outcome after lateral release. Patellar hypermobility is another risk factor for a poor out-



come. Other procedures that have been done to address patellar tilt are lateral retinacular lengthen-ing and medial retinacular tightening.

Lateral release for PFPS was more common during the 1990s but has since fallen out of favor. It was found that patient selection is very important when considering lateral release as a treatment for PFPS. Lateral release is more effective in patients with patellar tilt and a medial congruence angle.63 If lateral release is performed on patients without objective evidence of patellar tilt, their pain can worsen.64 In some cases, lateral release can lead to medial subluxation or even dislocation. Lateral release should only be considered in the setting of a tight lateral retinaculum causing excessive patel-lar tilt below horizontal. If this finding is not present, the procedure should not be performed.

Severe patellar MalalignmentProcedures to correct patellar alignment would

be expected to improve the pain in PFPS. Tor-

sional osteotomy to realign the patella has shown benefit even in patients without dislocation.65 How-ever, most studies are retrospective and have no comparison to conservative therapy, and many patients have continued pain after realignment. Pa-tients with patellar malalignment who benefit most from surgery in PFPS are those with concomitant pathologies such as chondromalacia or patellar dislocation. There are some patients with isolated PFPS who will benefit from surgery, but their pain and disability must be severe before considering surgery.

trochlear dysplasiaTrochlear dysplasia is a deformity of the femur

characterized by a shallow trochlear groove. It is associated with PFPS, chondromalacia, and recur-rent dislocation. There is evidence that trochlear dysplasia has both congenital and developmental causes. Developmental causes include lateral pa-tellar tracking, which can lead to a shallow trochlea.

Figure 6. Structure of the lateral retinaculum. (Adapted with per-mission from Clifton R, Ng CY, Nutton RW. What is the role of lateral retinacular release? J Bone Joint Surg Br 2010;92:2.)

Figure 7. Lateral retinacular release. (Adapted with permission from Clifton R, Ng CY, Nutton RW. What is the role of lateral re-lease? J Bone Joint Surg Br 2010;92:1–6.)

extent of lateral releaseStandardextended

Superficial layer

Epicondylopatellar bandLateral patellofemoral

ligament

Patellotibial band

Lateral collateral ligament

Gerdy’s tubercleFibula

Tibia

Patella

Vastus medialis obliquus

Medial patellofemoral ligament

Medial patellotibial ligament



The surgical approach to trochlear dysplasia can involve either soft tissue or bony procedures. The most direct approach to dysplasia is sulcus deepening trochleoplasty. Dislocation is rare after this reconstructive surgery, but chronic pain is common.66 Soft-tissue procedures such as medial patellofemoral ligament reconstruction are recom-mended as first-line surgical treatment even in severe cases of trochlear dysplasia.

Summary

PFPS is very common and a significant source of disability among runners and other athletes. PFPS has a strong association with patellofemoral instability, and it is important to distinguish sublux-ation from true dislocation. The diagnosis of PFPS can be made by history and physical exam alone. Physical examination should include dynamic as-sessment of the knee as well as the hips, feet, and gait. Diagnostic imaging is not necessary but can help to assess patellar alignment and help to rule out other pathology.

The etiology of PFPS is multifactorial, and thus treatment selection should be focused accord-ing to the patient’s specific pathology. Physical therapy remains the mainstay of treatment, but there are many different ways to treat PFPS with physical therapy. The literature is not clear on which therapies work best, but it seems that vari-ous patients will respond to different treatments based on their underlying pathology. Knee brac-ing, patellar taping, and foot orthotics may be helpful in some patients. When tailoring treatment for patients, it is important to keep in mind that PFPS is also an overuse injury and this should be addressed as part of patient counseling. Surgery should not be considered for pain alone until all other forms of treatment have failed. Furthermore,

surgery is only helpful if there is a specific struc-tural problem to address.

referenceS

1. Devereaux MD, Lachmann SM. Patello-femoral arthralgia in athletes attending a Sports Injury Clinic. Br J Sports Med 1984;18:18–21.

2. Insall JN. Foreword. In: Scuderi GR, editor. The patella. New York: Springer-Verlag; 1995.

3. Magee DJ. Orthopedic physical assessment. 4th ed. Phila-delphia (PA): Saunders Elsevier; 2006.

4. Dhaher YY, Kahn LE. The effect of vastus medialis forces on patello-femoral contact: a model-based study. J Bio-mech Eng 2002;124:758–67.

5. Besier TF, Fredericson M, Gold GE, et al. Knee muscle forces during walking and running in patellofemoral pain patients and pain-free controls. J Biomech 2009;42:898–905.

6. Lin F, Wilson NA, Makhsous M, et al. In vivo patellar tracking induced by individual quadriceps components in individuals with patellofemoral pain. J Biomech 2010;43:235–41.

7. Powers CM. The influence of abnormal hip mechanics on knee injury: a biomechanical perspective. J Orthop Sports Phys Ther 2010;40:42–51.

8. Cowan SM, Crossley KM, Bennell KL. Altered hip and trunk muscle function in individuals with patellofemoral pain. Br J Sports Med 2009;43:584–8.

9. Geiser CF, O’Connor KM, Earl JE. Effects of isolated hip abductor fatigue on frontal plane knee mechanics. Med Sci Sports Exerc 2010;42:535–45.

10. Willson JD, Kernozek TW, Arndt RL, et al. Gluteal muscle activation during running in females with and without patel-lofemoral pain syndrome. Clin Biomech (Bristol, Avon) 2011;26:735–40.

11. Aminaka N, Pietrosimone BG, Armstrong CW, et al. Patel-lofemoral pain syndrome alters neuromuscular control and kinetics during stair ambulation. J Electromyogr Kinesiol 2011;21:645–51.

12. Souza RB, Powers CM. Differences in hip kinematics, muscle strength, and muscle activation between subjects with and without patellofemoral pain. J Orthop Sports Phys

BOard review QueStiOnSTest your knowledge of this topic.

go to www.turner-white.com and select Orthopaedic Surgery from the drop-down menu of specialties.



Ther 2009;39:12–9.13. Baldon Rde M, Nakagawa TH, Muniz TB, et al. Eccentric

hip muscle function in females with and without patello-femoral pain syndrome. J Athl Train 2009;44:490–6.

14. Boling MC, Padua DA, Alexander Creighton R. Concen-tric and eccentric torque of the hip musculature in indi-viduals with and without patellofemoral pain. J Athl Train 2009;44:7–13.

15. White LC, Dolphin P, Dixon J. Hamstring length in patel-lofemoral pain syndrome. Physiotherapy 2009;95:24–8.

16. Van Tiggelen D, Cowan S, Coorevits P, et al. Delayed vas-tus medialis obliquus to vastus lateralis onset timing con-tributes to the development of patellofemoral pain in previ-ously healthy men: a prospective study. 2009;37:1099–105.

17. Singer BJ, Silbert PL, Song S, et al. Treatment of refrac-tory anterior knee pain using botulinum toxin type A (Dysport) injection to the distal vastus lateralis muscle: a randomised placebo controlled crossover trial. Br J Sports Med 2011;45:640–5.

18. Aminaka N, Pietrosimone BG, Armstrong CW, et al. Patel-lofemoral pain syndrome alters neuromuscular control and kinetics during stair ambulation. J Electromyogr Kinesiol 2011;21:645–51.

19. Powers CM. The influence of altered lower-extremity ki-nematics on patellofemoral joint dysfunction: a theoretical perspective. J Orthop Sports Phys Ther 2003;33:639–46.

20. Tiberio D. The effect of excessive subtalar joint pronation on patellofemoral mechanics: a theoretical model. J Or-thop Sports Phys Ther 1987;9:160–5.

21. Barton CJ, Levinger P, Crossley KM, et al. Relationships between the Foot Posture Index and foot kinematics dur-ing gait in individuals with and without patellofemoral pain syndrome. J Foot Ankle Res 2011;4:10.

22. Barton CJ, Levinger P, Menz HB, Webster KE. Kinematic gait characteristics associated with patellofemoral pain syn-drome: a systematic review. Gait Posture 2009;30:405–16.

23. Souza RB, Draper CE, Fredericson M, Powers CM. Femur rotation and patellofemoral joint kinematics: a weight-bearing magnetic resonance imaging analysis. J Orthop Sports Phys Ther 2010; 40:277–85.

24. Fredericson M, Yoon K. Physical examination and patellofem-oral pain syndrome. Am J Phys Med Rehabil 2006;85:234–43.

25. Insall J, Falvo KA, Wise DW. Chondromalacia patellae. A prospective study. J Bone Joint Surg Am 1976;58:1–8.

26. Haim A, Yaniv M, Dekel S, Amir H. Patellofemoral pain syndrome: validity of clinical and radiological features. Clin Orthop Relat Res 2006;451:223–8.

27. Park SK, Stefanyshyn DJ. Greater Q angle may not be a risk factor of patellofemoral pain syndrome. Clin Biomech (Bristol, Avon) 2011;26:392–6.

28. Sheehan FT, Derasari A, Fine KM, et al. Q-angle and J-sign: indicative of maltracking subgroups in patellofemoral pain. Clin Orthop Relat Res 2010;468:266–75.

29. Amis AA, Oguz C, Bull AM, et al. The effect of trochleo-plasty on patellar stability and kinematics: a biomechanical study in vitro. J Bone Joint Surg Br 2008;90:864–9.

30. Watson CJ, Leddy HM, Dynjan TD, Parham JL. Reliability of the lateral pull test and tilt test to assess patellar align-ment in subjects with symptomatic knees: student raters. J Orthop Sports Phys Ther 2001;31:368–74.

31. Davies PD, Costa ML, Donnell ST, et al. The sulcus angle and malalignment of the extensor mechanism of the knee. J Bone Joint Surg Br 2000;82-B:1162–6.

32. Grelsamer RP, Bazos AN, Proctor CS. Radiographic analy-sis of patellar tilt. J Bone Joint Surg 1993;75B:822–4.

33. Phillips CL, Silver DAT, Schranz PJ, et al. The measure-ment of patellar height. J Bone Joint Surg Br 2010;92-B:1045–53.

34. Brody LT, Thein JM. Nonoperative treatment for patello-femoral pain. J Orthop Sports Phys Ther 1998;28:336–44.

35. Tan SS, van Linschoten RL, van Middelkoop M, et al. Cost-utility of exercise therapy in adolescents and young adults suffering from the patellofemoral pain syndrome. Scand J Med Sci Sports 2010;20:568–79.

36. Natri A, Kannus P, Jarvinen M. Which factors predict the long-term outcome in chronic patellofemoral pain syn-drome? A 7-yr prospective follow-up study. Med Sci Sports Exerc 1998;30:1572–7.

37. Roush MB, Sevier TL, Wilson JK, et al. Anterior knee pain: a clinical comparison of rehabilitation methods. Clin J Sport Med 2000;10:22–8.

38. Irish SE, Millward AJ, Wride J, et al. The effect of closed-kinetic chain exercises and open-kinetic chain exercise on the muscle activity of the vastus medialis oblique and vastus lateralis. J Strength Cond Res 2010;24:1256–62.

39. Hanten WP, Schulthies SS. Exercise effect on electromyo-graphic activity of the vastus medialis oblique and vastus lateralis muscles. Phys Ther 1990;70:561–5.

40. Garcia FR, Azevedo FM, Alves N, et al. Effects of electrical stimulation of vastus medialis obliquus muscle in patients with patellofemoral pain syndrome: an electromyographic analysis. Rev Bras Fisioter 2010;14:477–82.

41. Bizzinin M, Childs JD, Piva SR, et al. Sysytematic review of the quality of randomized controlled trials for patellofemoral pain syndrome. J Orthop Sports Phys Ther 2003;33:4–20.

42. Tyler TF, Nicholas SJ, Mullaney MJ, McHugh MP. The role of hip muscle function in the treatment of patelofemoral pain syndrome. Am J Sport Med 2006;34:630–6.

43. Boling MC, Bolgla LA, Mattacola CG, et al. Outcomes of a weight-bearing rehabilitation program for patients diag-nosed with patellofemoral pain syndrome. Arch Phys Med



Rehabil 2006;87:1428–35.44. Nakagawa TH, Muniz TB, Baldon Rde M, et al. The effect

of additional strengthening of hip abductor and lateral ro-tator muscles in patellofemoral pain syndrome: a random-ized controlled pilot study. Clin Rehabil 2008;22:1051–60.

45. Souza RB, Powers CM. Predictors of hip internal rotation during running: an evaluation of hip strength and femoral structure in women with and without patellofemoral pain. Am J Sport Med 2009;37:579–87.

46. Noehren B, Scholz J, Davis I. The effect of real-time gait retraining on hip kinematics, pain, and function in sub-jects with patellofemoral pain syndrome. Br J Sports Med 2010;45:691–6.

47. Wu CC, Chou SW, Hong WH. Effectiveness of goosestep training or its modification on treating patellar malalignment syndrome: clinical, radiographic, and electromyographic studies. Arch Orthop Trauma Surg 2009;129:333–41.

48. Coppack RJ, Etherington J, Wills AK. The effects of exer-cise for the prevention of overuse anterior knee pain. Am J Sport Med 2011;39:940–8.

49. Piva SR, Fitzgerald GK, Wisniewski S, Delitto A. Pre-dictors of pain and function after rehabilitation in pa-tients with patellofemoral pain syndrome. J Rehabil Med 2009;41:604–12.

50. Collins N, Crossley K, Beller E, et al. Foot orthoses and physical therapy in the treatment of patllofemoral pain syn-drome: randomized clinical trial. BMJ 2008;337:a1735.

51. Barton CJ, Menz HB, Crossley KM. The immediate effects of foot orthoses on functional performance in individu-als with patellofemoral pain syndrome. Br J Sports Med 2011;45:193–7.

52. Barton CJ, Menz HB, Levinger P, et al. Greater peak rear-foot eversion predicts foot orthoses efficacy in individu-als with patellofemoral pain syndrome. Br J Sports Med 2011;45:697–701.

53. Thijs Y, Van Tiggelen D, Roosen P, et al. A prospective study on gait-related intrinsic risk factors for patellofemoral pain. Clin J Sport Med 2007;17:437–45.

54. McConnell J. The management of chondromalacia patella: a long term solution. Aust J Physiother 1986;32:215–23.

55. Ng GY, Wong PY. Patellar taping affects vastus medialis obliquus activation in subjects with patellofemoral pain before and after quadriceps muscle fatigue. Clin Rehabil 2009;23:705–13.

56. Derasari A, Brindle TJ, Alter KE, Sheehan FT. McConnell taping shifts the patella inferiorly in patients with patel-lofemoral pain: a dynamic magnetic resonance imaging study. Phys Ther 2010;90:411–9.

57. Mostamand J, Bader DL, Hudson Z. The effect of patellar taping on joint reaction forces during squatting in subjects with patellofemoral pain syndrome (PFPS). J Bodywork Move Ther 2010;14:375–81.

58. Lan TY, Lin WP, Jiang CC, Chiang H. Immediate effect and predictors of effectiveness of taping for patellofemoral pain syndrome. Am J Sports Med 2010;38:1626–30.

59. Denton J, Willson JD, Ballantyne BT, et al. The addition of the Protonics brace system to a rehabilitation protocol to address patellofemoral pain syndrome. J Orthop Sports Phys Ther 2005;35:210-19.

60. Lun VM, Wiley JP, Meeuwisse WH, et al. Effectiveness of patellar bracing for treatment of patellofemoral pain syn-drome. Clin J Sport Med 2005;15:235–40.

61. Kettunen JA, Harilainen A, Sandelin J, et al. Knee arthros-copy and exercise versus exercise only for chronic patel-lofemoral pain syndrome: a 5-year follow-up. Br J Sports Med 2011 Feb 25. [Epub ahead of print]

62. O’Neill DB. Open lateral retinacular lengthening compared with arthroscopic release. A prospective randomized out-comes study. J Bone Joint Surg Am 1997;79:1759–69.

63. Lokietek JC, Legaye J, Decloedt PH, et al. When should one divide the lateral patellar retinaculum? J Bone Joint Surg Br 1993;75(suppl 2):141–2.

64. Fulkerson JP. Patellofemoral disorders: evaluation and management. J Am Acad Orthop Surg 1994;2:124–32.

65. Dickschas J, Harrer J, Pfefferkorn R, Strecker W. Opera-tive treatment of patellofemoral maltracking with torsional osteotomy. Arch Orthop Trauma Surg 2011 Apr 10. [Epub ahead of print]

66. Bollier M, Fulkerson JP. The role of trochlear dysplasia in patel-lofemoral instability. J Am Acad Orthop Surg 2011;19:8–16.

Copyright 2013 by Turner White Communications Inc., Wayne, PA. All rights reserved.

patellofemoral pain syndrome - turner white · pdf filepateoemora ain syndrome orthopaedic...

Documents