[A minimally invasive dorsal approach to the medial femoral condyle as a donor site for osteochondral transfer procedures].

OBJECTIVE

Long-lasting reconstruction of joint surface by using an osteochondral transfer procedure (OCT). Reduction of donor site morbidity by using a minimally invasive approach to the dorsal medial femoral condyle.

INDICATIONS

Grade 3 and 4 cartilage lesions (according to ICRS [International Cartilage Repair Society]), osteochondral lesions, and osteochondrosis dissecans.

CONTRAINDICATIONS

Grade 2 or higher-graded cartilage lesions at the dorsal medial femoral condyle, infection, axis deviation of more than 5 degrees in the frontal plane, advanced osteoarthritis.

SURGICAL TECHNIQUE

Cylinders at recipient site are removed first, thereby determining number and diameter of donor cylinders. Supine position, skin incision over the dorsal medial femoral condyle. After dissection of soft tissue and superficial fascia, semitendinosus tendon and medial gastrocnemius muscle are retracted to the lateral side, followed by arthrotomy, introduction of two Hohmann retractors medial and lateral of the condyle, and harvesting of the donor cylinders with a tubular chisel. Advantages of the described approach: reduction of soft-tissue trauma, easy surgical technique, additional donor site area besides femoral trochlea and intercondylar notch.

POSTOPERATIVE MANAGEMENT

Partial weight bearing of 10-20 kg for 4-6 weeks. Limitation of knee flexion to 90 degrees for 6 weeks.

RESULTS

Between 01/2006 and 04/2007, the dorsal medial femoral condyle was used as a donor site in 16 patients. All patients were evaluated preoperatively and after 1 year using the American Knee Society Score (KSS), the Western Ontario and McMaster Universities (WOMAC) Score, the Tegner Score, and the visual analog scale (VAS) pain. The mean follow- up was 13.9 (+/-4.3) months. The mean defect area was 4.6 (+/-2.2) cm(2). The mean KSS, Tegner Score, and WOMAC Score improved from 123.1 (+/-41.5), 2.8 (+/-0.9), and 73.3 (+/-50.2) points preoperatively to 171.3 (+/-16.9), 3.4 (+/-0.6), and 26.1 (+/-17.6) points after 13.9 months (p < 0.05). The VAS pain improved from 5.3 (+/-2.7) to 2.4 (+/-1.8) points (p < 0.05). One patient with an osteochondral defect of 8 cm(2) at the medial femoral condyle (Ahlbäck's disease) still complains of pain during deep squatting. The dorsal medial femoral condyle can be recommended as donor site for OCT. The minimally invasive approach has proven to be safe and simple with a low complication rate.