[The surgical treatment of chronic extension deficits of the knee]

Abstract

Objective: Restoration of full knee extension in patients with chronic extension deficits, especially in posttraumatic and postoperative cases.

Indications: Chronic knee extension deficits of more than 10 degrees .

Contraindications: Local intraarticular problems caused by cyclops syndrome, graft hypertrophy or graft impingement after anterior cruciate ligament reconstruction (notch impingement). These patients should be treated with arthroscopic procedures. Spastic flexion contracture. Noncompliant patients. Acute or chronic infections. Poor soft-tissue conditions on site of surgery.

Surgical technique: If necessary, arthroscopy before arthrolysis to assure that the extension deficit is not caused by a local problem (cyclops, osteophytes, graft hypertrophy or graft impingement after anterior cruciate ligament reconstruction). Anterior skin incision at the medial border of the patellar ligament. Resection of Hoffa's fat pad, which is extremely fibrotic in almost all cases. Second skin incision at the posteromedial side of the knee joint. Incision of the medial retinaculum between the posterior border of the medial collateral ligament and the posterior oblique ligament. Posteromedial arthrotomy between the distal part of the tendon of the adductor magnus muscle and the posterior horn of the medial meniscus. Release of all adhesions in the posterior recess of the knee joint. Complete release of the posterior joint capsule from the femoral shaft.

Postoperative management: Immobilization for 48 h after surgery in full extension (no knee motion allowed in the first 48 h). For 48 h after surgery only short walks to the bathroom are allowed. Special dynamic extension brace (Dynasplint((R)), CDS((R)) Forte, Albrecht company, Stephanskirchen, Germany) for 4-6 weeks after surgery 6-8 h per day. Painkillers following WHO (World Health Organization) protocol. Manual lymph drainage and electric muscle stimulation help to decrease pain and swelling. Physiotherapy twice daily starting at the 2nd postoperative day. No flexion exercises for the first 7 days after surgery. 15 kg partial weight bearing for 4-6 weeks. Daily physiotherapy is recommended after discharge.

Results: 121 patients underwent anterior and posterior arthrolysis between 1990 and 2000. 86 of these patients could be included in this study. The average follow-up was 4.6 years (1-10 years). The extension deficit before surgery averaged 20 degrees compared with the opposite side. At follow-up, the average extension had increased by 17 degrees , no patient had more than 5 degrees of flexion contracture. The Lysholm Score was 84 postoperatively. The Tegner Activity Scale increased from 1.9 to 4.0 after arthrolysis. In the AOSSM Subjective Outcome Score, 35 patients showed excellent and 60 good results. 14 patients were satisfied after surgery and nine were not. Three patients required revision surgery (two synovial fistulas, one hematoma).