Arthroscopic lateral release of the patella with electrocautery was first reported in the literature in 1982 (10). Its prime advantage over standard lateral release procedures is the potential to minimize postoperative bleeding and subsequent hemarthrosis. The reported rate of significant postoperative hemarthrosis has decreased from more than 15% to less than 5% with the use of electrocautery (6). Other advantages of this technique include improved arthroscopic visualization during transection of the lateral retinaculum and a decrease in postoperative pain by minimizing the potential for significant postoperative hemarthrosis. This allows the patient to participate in an earlier, aggressive rehabilitation program that may improve the ultimate results of surgery.

The indications for arthroscopic lateral release of the patella have changed over the past decade and are much narrower today than in the past. The procedure has significant potential complications and should be performed only in selected cases. Our current indications for arthroscopic lateral release of
the patella include patients with recalcitrant anterior knee pain unresponsive to conservative treatment with:

The exact mechanism whereby lateral release is effective in relieving pain is unknown. Current theories include:

Arthroscopic lateral release of the patella is not indicated for the treatment of chronic anterior knee pain in adolescents with normal patellar tracking.

Conservative therapy is successful in treating most cases of anterior knee pain syndrome. This therapy ideally consists of 6 to 12 months of activity modification, selective use of anti-inflammatory agents, and a carefully structured exercise and stretching program. Patients are instructed to limit those activities that exacerbate their symptoms. They are encouraged to substitute other pain-free activities to maintain muscle strength, flexibility, and aerobic fitness. The therapeutic exercise program begins with the stretching of tight muscle-tendon units (e.g., hamstrings, triceps surae, iliotibial band, hip flexors) as well as the strengthening of weak muscles [e.g., quadriceps, vastus medalis oblique (VMO), hip external rotators]. Initially, isometric exercises are performed at or near full extension. Later, short-arc isotonic exercises and closed-chain quadriceps exercises are added. Emphasis should be on pain-free functional exercises for the entire lower extremity kinetic chain.

Various mechanical devices may also be used, including a Polumbo-style brace, a neoprene patellar sleeve, or orthotics to prevent excessive foot pronation. McConnell taping may be helpful during therapy sessions and when exercising to improve patellar tracking and relieve lateral facet compression (5). Braces that attempt to simulate the effects of McConnell taping are available. Additional braces have been introduced for patients with recalcitrant anterior knee pain who demonstrate tightness of the iliotibial band (Ober test) and hip flexors (Thomas test), with anterior pelvic tilt on physical examination. These braces have provided mixed results in treating patients with patellofemoral pain in our practice. Likewise, ultrasonography, phonophoresis, and iontophoresis have not been very helpful in our therapeutic programs for anterior knee pain. We have used them to treat localized soft-tissue areas that are symptomatic.

The great majority of patients with anterior knee pain will respond to a nonsurgical protocol (4). Once the symptoms have improved, we encourage a maintenance exercise program done a minimum of three times per week, and a gradual return to full activity. Surgery is offered only after attempts at nonsurgical treatment have failed and the patient is unwilling to live with the persisting symptoms (8). It is important that patients have realistic expectations of the success and failure rate of a lateral release in relieving their anterior knee pain.

Patient evaluation begins with a careful detailed history. It is important to note whether the onset of the presenting pain was insidious or related to a specific or repetitive trauma. Acute anterior knee pain associated with a large hemarthrosis can be associated with a recent patellar subluxation or dislocation. These patients should also be evaluated for injury to the anterior cruciate ligament, since both can occur secondary to hyperextension of the knee. Rupture of the quadriceps or patellar tendon is an infrequent finding but needs to be ruled out, particularly in older patients. Localization of the type and character of pain is quite helpful, including location, duration, frequency, exacerbating activities, alleviating maneuvers, and previous treatments. Subtle malalignment may be associated with anterior knee pain that is typically worse with squatting, stair climbing, and prolonged knee flexion. Teenage females commonly experience self-limited anterior knee pain that resolves over a period of time. A history of recurrent effusions may suggest articular cartilage degeneration of the undersurface of the patella and/or trochlea.

The history usually provides a good indication of the diagnosis, which is then confirmed by a thorough physical examination. Key points of the physical examination include assessment of the sitting Q angle, patellar inhibition test, patellar apprehension test, active and passive patellar tracking, and specific muscle tightness. The Q angle has traditionally been measured with the knee in full extension. A sitting Q angle (tubercle sulcus angle) is a better measure of the relationship of the two vectors of the quadriceps and the patellar tendon. At 90 degrees of knee flexion, the tibial tubercle should be directly under the center of the femoral sulcus, or at an angle of 0 degrees. If it is lateral, or at a valgus angle, this indicates lateralization of the tibial tubercle (3). In addition, the presence of VMO atrophy or hypoplasia should be assessed. Comparison of the VMO musculature to the vastus lateralis should be noted, as well as whether the contraction is concentric. The patella should track smoothly through an active range of motion, without abrupt or sudden movements. Crepitus with flexion and extension may be present but does not always correlate with pain or the degree of chondromalacia. Facet tenderness and retinacular pain should also be documented.

The evaluation for patellar tilt and glide is an important part of the physical examination. Patellar tilt is performed with the patient in the supine position and the knee in full extension. Normally, the lateral side of the patella can be elevated above the horizontal. Inability to do this indicates tightness of lateral restraints, and correlates with a higher success rate with surgery in symptomatic patients who undergo lateral release. Testing of the patellar glide is performed with the knee in 30 degrees of flexion. A lateral glide of greater than 75% of the patellar width suggests incompetent medial restraints, whereas a medial glide of less than 25% indicates tightness of the lateral restraints (5).

Hamstring tightness may be associated with increased loads on the patellofemoral joint. This can be assessed by measuring the popliteal angle with the patient supine and the hip flexed to 90 degrees. With the patient supine, flex the hip and knee to 90 degrees. Then slowly extend the knee until muscle resistance is felt, keeping the low back flat. The knee should be fully extended. If the hamstrings are tight, the knee will remain flexed, and this angle short of full extension can be recorded. An Ober test should be performed to rule out iliotibial band contracture. This is performed with the patient on his side with the involved leg uppermost. The leg is abducted with the knee flexed to 90 degrees while keeping the hip joint in neutral to slight extension. With release of the abducted leg, the thigh should drop to an adducted position if the iliotibial tract is normal. However, the thigh will remain abducted if there is a contracture of the iliotibial band. Hip flexor tightness should be evaluated by performing a Thomas test. The patient should be supine with his pelvis level. Both hips are maximally flexed to the chest. Have the patient hold the uninvolved leg on the chest while letting the involved leg down until it is as straight as possible. The extent of a hip flexion contracture can be estimated by observing the angle between the leg and the table. Recently, anterior pelvic tilt with hip muscular strength abnormalities has been shown to be associated with patellofemoral pain. Reducing postural habits that cause anterior pelvic tilt while strengthening hip flexors and abductors may be effective in this group of patients. Weakness of the hip musculature can be evaluated via a single leg squat test.

In general, both extremities should be examined for side-to-side differences, and routine evaluation for meniscal and ligamentous pathology should be performed. Foot pronation is associated with obligatory internal tibial rotation and may contribute to anterior knee pain in patients with flatfoot deformity. These patients may benefit from orthotics. Referred pain from the low back or hip should be excluded by performing a straight-leg raise test and examining hip range of motion. In addition, the patient should be checked for generalized ligamentous laxity, which may be associated with patella alta and lateral subluxation or dislocation of the patella.