(Previously on the site of stoneclinic.com article deleted in November 2001 this is a copy) Osteochondritis Dessicans Lesions (OCD)
of the Knee Contact between the end of the femur (thigh bone) and the top of the tibia (shin bone) occur at the knee joint. The surfaces of these bones in the joint have protective covers made up of articular cartilage. This cartilage optimizes weight distribution over the joint surface, minimizes friction and wear, and allows for a smooth glide over the joint surface with motion. Beneath this protective cover lies subchondral bone followed by cancellous bone. People with osteochondritis dessicans (OCD) have a disease process in which there is a localized osteocartilaginous separation at the level of the subchondral bone that can damage this protective cover producing pain and swelling. Unless the lesion repairs spontaneously or it is treated, the disease process will progress. The area of subchondral bone with its attached articular cartilage can become loose and fall into the joint. In fact, this is the most common source of loose bodies in the knee joint. OCD lesions may occur in any joint, but they most often occur in the knee. This disease presents more often in men than in women and afflicts people between the ages of 10-50 years old. The cause is unknown. Accepted theories have included (1) direct trauma to the joint; (2) joint instability and or internally injured structures of the joint such as meniscal tears and patellar dislocations; (3) a decrease or absence of blood flow to the subchondral area possibly due to a clot in the end arteries that supply the affected area; (4) abnormal bone development; and (5) a predisposition to develop OCD, genetic or otherwise. Symptoms may include a chronic knee ache, swelling or if the segment becomes loose there may be a sensation of popping or catching. A loose body may even be palpable in the joint. Physical exam by a physician may only reveal minimal findings. X-rays are diagnostic and an MRI is beneficial for further assessment of a lesion for size and viability. The treatment of OCD lesions depends on the patient’s age and the size of the lesion. Treatment options for patients whom first present with symptoms may include non-operative treatment or surgical treatment. Many children respond well to non-operative treatment while adults require diagnostic arthroscopy to evaluate the lesion and potentially treat the lesion as well. At arthroscopy lesions can be classified into 4 groups. The first consists of an intact lesion with a continuous, however mildly irregular articular cartilaginous surface. In the second group there are signs of early separation with the articular surface showing increasing irregularity. In the third group the lesion becomes partially detached. Lastly, the fourth group reveals a crater at the surface of the bone and a loose body is present. Surgical procedures to treat these lesions have included open or arthroscopic drilling, debridement, reduction and fixation with Smillie pins or Herbert screws, bone grafting, autologous chondrocyte implantation, osteochondral autografts, periosteal/perichondral autografts, and osteochondral allografts. If treatment fails, an even larger lesion may be the result. Orthopaedists are then faced with difficult questions regarding future therapy. Their choices may include attempting another trial of the surgical treatments listed above or possibly a total or partial knee replacement. With many of these patients being young and the fact that knee replacements need replacing every 10-20 years makes the knee replacement a less desirable option. Arthroscopic articular cartilage paste grafting has been used by Dr. Stone to treat arthritic and traumatic lesions in the knee in over 120 cases for nine years with good pain relief. The goal of treatment of arthritic lesions, traumatic lesions, and failed OCD lesions where a defect exists is the same. The intent is to stimulate a healing response to cover these lesions with a protective cover of fibrocartilage and or hyaline cartilage to reduce pain and swelling. The paste graft procedure has been successfully applied to OCD lesions that failed standard treatments. The following are the stories of 2 people who had failed previous surgical treatment and underwent further successful treatment with articular cartilage paste grafting.
JL was a twenty-five year old athletic male who presented after failing a Herbert screw fixation of a large Osteochondritis Dessicans lesion. He recalled initially injuring his knee at age 12 and developed progressive knee pain such that by his junior year in high school he had to hold on to the walls to walk. In 1990 at age18, x-rays revealed a large osteochonditis dessicans lesion involving the weight-bearing surface of the medial femoral condyle. It was felt that the OCD lesion was separating at that point in time and he subsequently underwent a knee arthrotomy (open knee surgery) with elevation of the articular cartilage flap, debridement of the crater, and flap fixation with 2 Herbert screws. He continued to have pain and popping. Arthrograms and x-rays appeared to show good position of the screws and the fragment. In October 1992, CT reportedly revealed a nonunion of the fracture fragment and in April of 1993 at diagnostic arthroscopy one of the Herbert screws was noted to be a little loose and the screw was tightened. The pain had progressed and at arthroscopy in January 1998, the screws and the unstable OCD lesion were removed (see photo) and he was referred for articular cartilage paste grafting. Preoperative x-rays and MRI revealed a large OCD lesion with underlying avascular necrosis involving a large portion of the femoral condyle.
At arthroscopy, a lesion measuring approximately 35 mm x 40mm was found with a depth of 30 mm.
The base was hard and sclerotic. The base of the lesion was morselized until bleeding occurred. Articular cartilage and cancellous bone were harvested from a non-weight bearing region of the knee. The articular cartilage and cancellous bone were then smashed forming a paste in a bone graft crusher and arthroscopically impacted into the lesion.
Postoperatively, the patient was kept non-weight bearing for four weeks using crutches. A CPM unit was used in a range of motion from zero degrees to 75 degrees for six hours each night for four weeks. Bike and pool exercises with minimal resistance were started at two weeks. Impact sports were started after three months. The patient noted immediate relief of pain. He stated that he had not been free of pain since he was twelve years old. At the 8 month follow up he graded his knee as normal in activities of daily living including walking, stairs, squatting/kneeling. He water-skied regularly. Three months later while squatting down with a flexed knee he felt a pop and developed immediate pain and swelling. Repeat arthroscopy in December 1998 revealed a hypertrophic healing response fully covering the defect.
In regards to pain, he rated his knee at 20 months after the original graft was placed as having no pain with all activities on the WOMAC Osteoarthritis Index.
DL, a 39-year-old engineer presented having failed an osteochondral autograft transplantation and fixation procedure to an OCD lesion located at the weight-bearing surface of the medial femoral condyle. He reportedly grew 5 inches in 4-5 months at approximately age 15 and developed the knee pain around that time. Beginning around age 18 he apparently underwent 3 surgical debridements (1978, 1985, and in 1986). Although the operative reports were not available it was speculated that the second surgery might have consisted of an abrasion chondroplasy to the lesion. In April of 1998 an OATS procedure (a type of osteochondral autografting) was performed at the central aspect of the lesion while a portion of the OCD lesion was stabilized using absorbable screws by his private physician. He was pain free until October 1998 and an MRI was obtained revealing a possibly large chondral defect and an apparent loose body.
The resorbable pins were removed at arthroscopy November 1998 and an articular cartilage paste graft was placed. The graft was applied to the 20mm by 25mm and 25mm in depth lesion at the medial femoral condyle using the same technique as previously described.
He was non-weight bearing using crutches and used a continuous passive motion machine for 4 weeks. He eventually returned to full sports and rated his knee as greatly improved. While rollerblading in December of 1999 he crashed onto the surgical knee. By February 2000 he developed increasing pain, catching, and limping. At arthroscopy, 14 months after the articular cartilage graft was placed, the condyle appeared well healed with a thickened fibrous cover. He is now without pain or swelling. He had been able to ski, golf, and jet ski without complaint. These patients presented with large defects on the weight bearing
surfaces of their medial femoral condyle and pain that had been
refractory to prior treatment. Through articular cartilage
grafting these people were successfully treated and reported having
dramatic pain relief.
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