WWW.SPORTEX-MEDICINE.COM

area is richly innervated and extremely sensitive to touch.

While the structures mentioned above may give rise to pain, it remains unclear where the pain is actually coming from, as many patients with malalignment do not experience symptoms.

The pain is likely to be coming from the peripatellar soft tissue struc- tures or from the subchondral bone but for individual patients the source of pain is often unclear.

How is the diagnosis made? The characteristic history and symptoms of PFPS is retropatellar pain for more than six weeks during physical activities such as jumping, running, squatting and going up and down stairs. Pseudo-locking and giving-way are also common symptoms. Patients with intra-articular pathology most often experience giving-way while turning, and that giving-way due to PFPS most frequently occurs walking up or down stairs or slopes.

The patient should exhibit two of the following clinical signs on assessment: ● Pain on direct compression of the patella against the femoral condyles with the knee in full extension (Fig.2) ● Tenderness on the posterior aspect of the patella on palpation (Fig.3) ● Pain on resisted knee extension (Fig.4) ● Pain with isometric quads contraction against suprapatella resistance with the knee in 15o of flexion (Fig.5).

These signs should be present in associa- tion with negative findings on examina- tion of knee ligaments, menisci, bursae,

Figure 4: Pain on resisted

knee extension Investigation X-ray - weight bearing AP, lateral X-ray - skyline (Merchant) views Ultrasound MRI scan Cine MRI Arthroscopy Table 4: Investigations for anterior knee pain

synovial plicae, Hoffa’s fat pad, iliotibial band and hamstrings, quadriceps and patellar tendons and their insertions. Previous studies indicate that these criteria are sensitive and specific for a diagnosis of PFPS.

PFPS is a clinical diagnosis based on careful history and clinical examina- tion that excludes other causes for anterior knee pain.

Investigations in AKP As PFPS is essentially a clinical diagnosis in the absence of other pathology, the place for investigations is limited. Patients however present with the symp- toms of anterior knee pain and it may be necessary to request investigations to exclude other significant pathology. Table 4 summarises suggested investigations for anterior knee pain.

The choice of investigation depends on

the clinical presentation. There is no place for blanket testing as this may give rise to false positive reporting. For exam- ple, the presence of hypoechogenic changes on the ultrasound of a tender patellar tendon increases the likelihood that patellar tendinopathy is the diagno- sis. It should be remembered that athletes without patellar tendon pain may also have these changes on ultrasound and so should not be requested for all athletes with anterior knee pain.

The treatment of PFPS Non-surgical treatment There is no consensus regarding how to manage a patient with PFPS. A practical approach to rehabilitation for PFPS based on the evidence available follows on from this article. The research upon which this programme is based is presented in this section.

Figure 5: Pain with isometric quads

contraction

Figure 2: Pain on patella compression

Studies are difficult to compare because of varying quality of study design and methodology. In a recent review, no stud- ies were found that fulfilled all the requirements for a randomised controlled trial (ie. randomisation, adequate alloca- tion concealment, blinding and follow up). Also no trial described measurements of compliance or co-interventions. Table 5 summarises the published randomised studies of non-operative therapy in PFPS.

Figure 3: Patella tenderness

Surgical treatment There are over 100 surgical procedures described for the treatment of patellofemoral pain disorders. Most, howev- er, have not been evaluated by randomised controlled trials. It is advised not to con-

SportEX 11 Suspected condition

Patellar stress fracture Sinding-Larsen syndrome Osteoarthritis

Osteochondral lesion Patellofemoral osteoarthritis Excessive lateral pressure syndrome (ELPS)

Patellar tendinopathy Pre-patellar bursitis Infra-patellar bursitis

Fat pad syndrome, meniscal pathology, patellar tendinopathy

Patellar subluxation Chondromalacia patellae, plica syndromes

TIP

TIP