Arthroscopic release for symptomatic scarring of the anterior interval of the knee

Abstract

Background: Patients with a history of knee trauma or previous surgery may exhibit pain in the infrapatellar region that is refractory to conservative care. This may be due to subtle scarring of the anterior interval.

Hypothesis: Arthroscopic release of a scarred anterior interval will lead to improvement in anterior knee pain.

Study design: Case series; Level of evidence, 4.

Methods: Twenty-five consecutive patients with isolated scarring of the anterior interval, confirmed with both magnetic resonance imaging (MRI) and arthroscopic examination, were included. All 25 patients had refractory anterior knee pain that was unimproved after a minimum of 6 months of physical therapy and nonsteroidal anti-inflammatory medications and pain during knee extension. All patients had a minimum of 2 previous surgical procedures, and 11 (44%) of the patients had a previous anterior cruciate ligament (ACL) reconstruction. All 25 (100%) patients had an apparent decrease in the cranial excursion of the patella and had a positive Hoffa test result. Fourteen (56%) patients had a preoperative flexion contracture of at least 5 degrees . All patients underwent an isolated arthroscopic anterior interval release.

Results: All patients were evaluated by physical examination and standardized scoring instruments with an average follow-up of 4.0 years (range, 2.0-7.2). Twenty-one patients had full range of motion of the patella in all directions and a negative Hoffa test finding at final follow-up. All 14 (100%) patients with preoperative flexion contractures (>5 degrees ) experienced a full return of extension. The average Lysholm score improved from 59 preoperatively to 81 postoperatively (P < .0001). The average International Knee Documentation Committee (IKDC) score improved from 49 to 70 (P < .001). There were no complications. Four patients (16%) had failed results and required a second surgical release. Patients with failures had significantly lower preoperative Lysholm scores (score = 40) than those who did not (score = 58) (P = .022). Three of the failures were workers' compensation cases.

Conclusion: Scarring of the anterior interval changes the mechanics of the anterior structures of the knee and may lead to refractory anterior knee pain. Arthroscopic anterior interval release successfully provides pain relief in this patient population.