REHABILITATION FOCUS

THE DIAGNOSIS AND TREATMENT OF

PATELLOFEMORAL PAIN SYNDROME

By Dr Alex Bennett, Dip Sports Med, MRCP and Dr Nick Carter, Dip Sports Med, MRCP

What is patellofemoral pain syndrome? Patellofemoral pain syndrome (PFPS) is a commonly misunderstood condition. This is illustrated by the many different names used for PFPS, the variety of pro- posed aetiologies and the numerous treatment programmes suggested.

Anterior knee pain (AKP) is possibly the most common presenting symptom in sports medicine. It can be caused by very different pathology. AKP is however a symptom and not a diagnosis. Conditions that give rise to AKP are summarised in table 1.

Firstly it is important to be aware that more than one cause of anterior knee pain may co-exist. For example, patellar tendinopathy (chronic degeneration of the patellar tendon) may co-exist with chondromalacia patellae (softening or fissuring of the retropatellar cartilage).

A diagnosis of PFPS can only be made once other causes of anterior knee pain have been excluded, though PFPS can also coexist with other causes of AKP, for example, PFPS may occur in a patient with an anterior meniscal tear.

Factors associated with PFPS Many observations have been made in patients suffering with PFPS that give rise to theories about the cause of the syn-

Common Less common Patellofemoral pain syndrome

Patellofemoral osteoarthritis

Patellar tendinopathy (figure 1) Pre- and infra-patellar bursitis Chondromalacia patellae Patellar subluxation Fat pad syndromes

Sinding-Larsen Syndrome Plica syndromes

Intra-articular pathology eg. meniscal tears Pain referred from the spine and hip Patellar stress fracture Excessive lateral pressure syndrome (ELPS)

Table 1. Causes of anterior knee pain Figure 1: MRI of patellar tendinopathy SportEX 9

PFPS is defined as peripatellar or retropatellar pain or both, that results from physical and biome- chanical changes in the patellofemoral joint, in the absence of other specific pathology.

drome and the source of pain. It is there- fore worth identifying which associations have been made in studies that have com- pared PFPS sufferers with non-sufferers from cross-sectional or retrospective stud- ies; and those which have identified dif- ferences between those who develop PFPS and those who do not, from prospective studies. This is important because some observations may have been influenced by pain (for example, muscle weakness and tightness and altered activity levels)

TIP