The Influence of Altered Lower-Extremity Kinematics on Patellofemoral Joint Dysfunction: A Theoretical Perspective

Abstract

Although patellofemoral pain (PFP) is recognized as being one of the most common disorders of the lower extremity, treatment guidelines and underlying rationales remain vague and controversial. The premise behind most treatment approaches is that PFP is the result of abnormal patellar tracking and/or patellar malalignment. Given as such, interventions typically focus on the joint itself and have traditionally included strengthening the vastus medialis oblique, taping, bracing, soft tissue mobilization, and patellar mobilization. More recently, it has been recognized that the patellofemoral joint and, therefore, PFP may be influenced by the interaction of the segments and joints of the lower extremity. In particular, abnormal motion of the tibia and femur in the transverse and frontal planes may have an effect on patellofemoral joint mechanics. With this in mind, interventions aimed at controlling hip and pelvic motion (proximal stability) and ankle/foot motion (distal stability) may be warranted and should be considered when treating persons with patellofemoral joint dysfunction. The purpose of this paper is to provide a biomechanical overview of how altered lower-extremity mechanics may influence the patellofemoral joint. By addressing these factors, better long-term treatment success and prevention may be achieved. J Orthop Sports Phys Ther 2003;33:639-646. Key Words: knee, patella, patellofemoral, pain A lthough patellofemoral pain (PFP) is a common clinical finding in a wide range of individuals, 1,12,39 the incidence is greater in physically active populations. 3,5,19,38 Despite its high prevalence, however, treatment guidelines and underlying rationales remain vague and controversial. 35 This is supported by the fact that there is no agreement on how PFP should be treated. For example, a myriad of conservative procedures have been advocated, 7,26,35,42,46,48,49 and numerous surgical techniques described. 2,8,15,24,47 A commonly accepted hypothesis concerning the etiology of PFP is related to increased patellofemoral joint stress and subsequent articular cartilage wear. 10,16,17,28,40 Patellar malalignment and/or abnormal patellar tracking is thought to be one of the primary precursors of patellofemoral joint pathology. 11,13,28,40 Acceptance of this theory is evident in clinical practice, as most interventions are focused on the patellofemoral joint itself, with the intention of influencing patellar motion (ie, strengthening the vastus medialis oblique, stretching, patellar taping, patellar bracing, soft tissue mobilization, and patellar mobilization).

Hip Strengthening Prior to Functional Exercises Reduces Pain Sooner Than Quadriceps Strengthening in Females With Patellofemoral Pain Syndrome: A Randomized Clinical Trial

“…Several authors have reported that females with PFPS demonstrate weaknesses of the hip external rotators and hip abductors. 11,17,26,30,31,36,37 During functional activities, especially single-leg activities, the hip muscles prevent hip adduction and internal rotation, which may result in dysfunctional lower extremity joint alignment and can lead to the development of PFPS. 20 …”

Analysis of Hip Strength in Females Seeking Physical Therapy Treatment for Unilateral Patellofemoral Pain Syndrome

“…17,21,24,25 Theoretically, weakness of the hip abductors and external rotators may be associated with poor control of eccentric femoral adduction and internal rotation during weight-bearing activities, leading to misalignment of the patellofemoral joint as the femur medially rotates underneath the patella. 21,22 Consequently, to reduce excessive lateral patellar deviations during weight-bearing activities and potentially reduce anterior knee pain, physical therapy intervention may need to address hip muscle performance to facilitate greater control of weightbearing femoral adduction and internal rotation. Specific activities targeting performance of the lateral hip musculature have been incorporated into physical therapy intervention programs for improving pain, disability, and function in patients with PFPS.…”

Effects of strength training on the treatment of patellofemoral pain syndrome - a meta-analysis of randomized controlled trials

“…This increased Q angle leads to patella subluxation, which intensifies the patellofemoral peak pressure, one of the causes of PFPS (31,32,33). In addition, weakness in these muscles may cause patellar facet overload (13,34).…”