Patellofemoral Stress Syndrome

Patellofemoral stress syndrome (PFSS) is a broad, nondescript term used in sports medicine to describe anterior knee pain when the true etiology is multifactorial or unknown. Multiple factors such as an increased Q angle, femoral anteversion, foot hyperpronation, gluteal/hip weakness, tight hamstrings, and patellar malalignment are suggested contributors to anterior knee pain. PFSS is commonly seen in adolescent females but occurs in males and females of all ages. Pain can be unilateral or bilateral and is not usually associated with trauma or injury. Pain occurs with prolonged walking, running, stair climbing, jumping, or prolonged sitting (theater sign), but not usually at rest or at night. Many adolescents experience an increase in pain when they return to sports activity, especially if they do not condition in the preseason. Pain may occur in athletes, nonathletes, or overweight adolescents.

Figure 3 Apprehension test for patellar instability. Placing your knee underneath the patient's knee to allow 30° of relaxed flexion, gently try to laterally sublux the patella. A look of apprehension or pain is a positive finding. Instability/laxity may be noted. Be careful not to displace too aggressively as one could dislocate the patella.

Figure 3 Apprehension test for patellar instability. Placing your knee underneath the patient's knee to allow 30° of relaxed flexion, gently try to laterally sublux the patella. A look of apprehension or pain is a positive finding. Instability/laxity may be noted. Be careful not to displace too aggressively as one could dislocate the patella.

Physical examination may show hyperpronation upon gait evaluation. There is typically no knee effusion and a normal ligament examination. There is frequently patellar hypermobility, medial and lateral patellar facet tenderness, and pain with patellar compression and apprehension testing (Fig. 3). There may also be patellar malalignment or maltracking. The vastus medialis, the medial quadriceps muscle, may be mildly atrophied. The athlete may experience pain with tightening of the quadriceps muscles. Hamstrings are typically tight (Fig. 4). Core strength is usually weak and single leg squats may reveal knee valgus (Fig. 5). Knee radiographs are usually normal but may reveal a laterally displaced patella or a shallow femoral groove on sunrise view.

Rehabilitation consists of daily physical therapy to increase flexibility of the hamstrings and hip flexors along with strengthening of the lower extremity and especially the core body. Pilates is an excellent way to strengthen the core body muscles. Icing for 15 to 20 minutes after activity and use of nonsteroidal anti-inflammatories (NSAIDs) after activity on an as needed basis provide some pain relief. McConnell taping or a patellar stabilizing brace helps provide central patellar alignment if tracking or subluxation is a problem. Avoiding running for conditioning and cross

Figure 4 Hamstring tightness/popliteal angle. With the patient relaxed and the hip and knee flexed to 90° gently try to extend the lower leg to gauge hamstring flexibility. Do not have the patient help push. Less than 160° (90° = lower leg horizontal) is considered tight.

Figure 5 Single leg squat for core body strength. Have the patient stand on one leg, and without holding on perform a single leg squat to 90° of knee flexion. If core body strength is good, the hip, knee, and ankle will remain in a straight vertical line as shown in (A). If core body strength is poor the knee will buckle into valgus as shown (B).

Figure 5 Single leg squat for core body strength. Have the patient stand on one leg, and without holding on perform a single leg squat to 90° of knee flexion. If core body strength is good, the hip, knee, and ankle will remain in a straight vertical line as shown in (A). If core body strength is poor the knee will buckle into valgus as shown (B).

training on the bike, elliptical machine or in the pool helps to decrease symptoms while allowing the athlete to remain active. Orthotics to correct hyperpronation along with supportive, new running shoes can also be recommended.

Case 2: A 14-year-old soccer player has a 3-month history ofleft knee pain without a mechanism of injury. Pain occurs at the tibial tuberosity with running and jumping and any time the area is hit. There is no knee effusion but the tibial tuberosity is prominent on the left side. Three years ago he had similar pain along the inferior patella. He has been growing a lot lately and has very tight hamstrings.

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