Osteochondritis Dissecans

The name osteochondritis dissecans (OCD) is a misnomer. In 1888, Konig coined the term when he sought to describe the pathologic process that led to atraumatic loose bodies of femoral origin in the knee and hip joints. Believing that an underlying inflammatory reaction of bone and cartilage was a major component of this process, he selected the terms osteochondritis, to refer to the inflammation of the osteochondral joint surface, and dissecans, derived from the Latin word dissec, which means to separate. However, investigators have failed to identify inflammatory cells in histologic sections of excised osteochondral loose bodies. Nevertheless, the name has persisted.

Images depicting osteochondritis dissecans are provided below:

OCD may occur in the knee, elbow, or ankle. See also Knee Osteochondritis Dissecans. For patient education information, see Knee Pain, Knee Injury, BrokenElbow, and Ankle Fracture.

In osteochondritis dissecans, a fragment of cartilage and subchondral bone separates from an articular surface. In 1840, Pare was first to describe the surgical removal of loose bodies, presumably osteochondral fragments, from joints.

For many years, the treatment of choice for OCD remained either arthrotomy with removal of the loose osteochondral fragment or conservative, nonoperative management. The latter option remains the treatment of choice for patients with early disease and open physes. In contrast, surgical options have traditionally included drilling of the site of the defect, removing the loose body, fixing the loose body to the site of separation, and placing osteochondral grafts. Current operative methods include fixation of the lesion, drilling of the site of the defect with removal of loose bodies, and autologous osteochondral mosaicplasty and autologous chondrocyte transplantation.[1, 2]

Osteochondritis dissecans is characterized by separation of an osteochondral fragment from the articular surface. The underlying bone from which the fragment separates has normal vascularity. This characteristic distinguishes OCD from osteonecrosis, in which the underlying bone is avascular.

OCD affects 2 distinct populations of patients differentiated by the status of their physes. Patients aged 5-15 years who have open physes have the juvenile form of the disease. Older adolescents and adults who have closed physes have the adult form of the disease. Symptoms of OCD depend on the stage of the lesion. If left untreated, OCD may lead to early degenerative changes with chronic pain and functional impairment.

Frequency

Prevalence

In the United States, the overall prevalence of osteochondritis dissecans is not known. However, in the femoral condyles, OCD has a prevalence of approximately 6 cases per 10,000 men and 3 cases per 10,000 women.

Involvement

OCD occurs in the knee 75% of the time, the elbow 6% of the time, and the ankle 4% of the time. In the knee, OCD occurs in the medial femoral condyle 75% of the time, on the weight-bearing surface of the medial condyle 10% of the time, on the weight-bearing surface of the lateral condyle 10% of the time, and in the anterior intercondylar groove or patella 5% of the time. In the ankle, OCD occurs in the posteromedial aspect of the talus 56% of the time and in the anterolateral aspect of the talus 44% of the time.

Sex

OCD has a male predominance, with a male-to-female ratio of 5:3.[3]

Age

The average age at presentation of juvenile OCD in the knee is 11.3-13.4 years. The average age at presentation of adult OCD in the knee is 17-36 years, but this form can occur in adults of any age. The average age at presentation of OCD in the ankle is 15-35 years. The average age at presentation of OCD in the elbow is 12-21 years.

The true etiology of osteochondritis dissecans has been the source of enthusiastic debate for decades. The etiology has been described as traumatic, ischemic, idiopathic, and hereditary. The debate continues, but most authors now believe that OCD is a result of multifactorial elements.[4]

Trauma

Trauma has been described as a potential etiology of OCD. In the knee, direct trauma could create a transchondral fracture; however, the predilection of OCD for the posterolateral portion of the medial femoral condyle suggests indirect trauma as a more likely cause. Repetitive impingement of the tibial spine on the lateral aspect of the medial femoral condyle during internal rotation of the tibia has also been suggested as a contributing factor.

In the ankle, traumatic insult is more widely accepted as the etiology of OCD, although not without controversy. Tibiotalar subluxation results in impingement of the talus on the tibia or fibula. Cadaveric studies have revealed that posteromedial talar lesions may result from ankle inversion while in plantar flexion so that the talus impacts and torques the posterior aspect of the tibial plafond. Anterolateral talar lesions may result from impaction of the talus on the fibula in inversion with the ankle in dorsiflexion. Occasionally, however, medial talar lesions are not associated with trauma. Many authors believe that while lateral lesions are the result of trauma, medial lesions may be more multifactorial.

Although the exact cause of elbow OCD is unclear, most authors agree that repetitive microtrauma plays an important role. Occasionally, a single traumatic insult to the elbow may be identified as a potential etiology. Overhead motions, such as pitching in baseball, produce an abnormal valgus stress on the elbow. The tensile stress placed on the medial aspect of the elbow during throwing results in compressive forces between the radial head and the capitellum, potentially leading to osteochondrotic changes. One group reviewed 18 cases of elbow OCD and noted that each lesion was related to repetitive throwing or repeated engagement in racquet sports.

Ischemia

Ischemia has been investigated as a potential etiology for OCD. Enneking reported that the vascular supply to the subchondral bone was akin to that of the bowel mesentery, with poor anastomoses to surrounding arterioles.[5] This propensity towards ischemia would naturally lead subchondral bone to form sequestra, making it particularly vulnerable to traumatic insult, resultant fracture, and potential separation. However, Enneking's report on the vasculature contradicts the findings of Rogers and Gladstone, who studied the vascularity of the distal part of the femur and found numerous anastomoses to intramedullary cancellous bone.[6] Further refuting the ischemic hypothesis, Chiroff and Cooke found no signs of avascular necrosis in sections of excised osteochondral loose bodies.[7]

Genetics

Several authors have investigated a potential genetic link for OCD. Petrie reviewed the evidence and found no definite genetic etiology for OCD.[4] However, at least 8 other authors have reported a hereditary influence for OCD. A systematic review of 86 studies of OCD of the knee found multiple reports of familial occurrence and frequent concordance in monozygotic twins.[8]  Ultimately, the link for most patients, if present, is probably minor. 

Once a lesion is present, it typically progresses through 4 stages unless appropriately treated.

• Stage I consists of a small area of compression of subchondral bone.
• Stage II consists of a partially detached osteochondral fragment. A radiograph of the bone may reveal a well-circumscribed area of sclerotic subchondral bone separated from the remainder of the epiphysis by a radiolucent line.
• Stage III lesions are the most common and consist of a completely detached fragment that remains within the underlying crater bed.
• Stage IV lesions consist of a completely detached fragment that is completely displaced from the crater bed. This is also termed a loose body.

Symptoms

The symptoms of OCD vary with the stage of the lesion. In the knee, lesions early in their course are associated with vague and poorly defined symptoms, including variable amounts of pain and swelling. As the lesion progresses, symptoms such as catching, locking, and giving-way are often noted. These symptoms are often intermittent and associated with exertion.

Patients should be questioned as to how often they experience symptoms. Symptoms that are constant and severe are typically associated with loose bodies within the knee. Symptoms that are increasing in frequency may indicate progression of the lesion. In addition, patients with loose bodies within the joint may note locking and be able to palpate a loose body in the affected joint.

Differentiating OCD from osteonecrosis is difficult, but the most significant clue is the age of the patient. Younger patients tend to develop OCD, and older patients tend to develop osteonecrosis.

Physical examination

Physical examination of any patient who reports knee or ankle problems should begin with examination of the patient's gait. In a patient with OCD of the knee, the affected leg may be externally rotated during gait in an attempt to avoid impingement of the tibial spine on the lateral aspect of the condyle. Patients with OCD in the knee may have quadriceps weakness, not gluteus maximus weakness; however, this does not lead to a lack of patellar tracking.

Next, check for atrophy or weakness of the quadriceps muscle. An effusion may be noted. During range-of-motion testing, the patient may lack full knee extension on the affected side. Upon palpation, the lesion is often tender. The Wilson test may be useful. In this test, the examiner is to first flex the affected knee to 90° then internally rotate the tibia and slowly extend the knee. As the knee is extended to approximately 30° of flexion, the tibial spine abuts the OCD lesion on the medial femoral condyle, causing pain. External rotation eliminates the pain by taking the tibial spine away from the OCD lesion. Therefore, this test is only valid for OCD on the medial femoral condyle, which is the most common area in the knee for OCD.

Patients with OCD of the ankle report ankle swelling and symptoms of catching with walking or with active ankle motion. Approximately 90% of patients reveal a clear history of previous trauma to the affected ankle. Patients may or may not report pain, depending on the stage of the lesion.

Physical examination of a patient with ankle OCD may reveal joint effusion, crepitus, and diffuse or localized tenderness. As the lesion progresses, the symptoms become more severe and localized. Pain with compression of the tibiotalar joint and crepitus with dorsiflexion or plantar flexion are common. Lateral lesions may cause more pain and tenderness than medial lesions.

Patients with OCD of the elbow often report an insidious onset of generalized joint pain, swelling, and intermittent limitation of their range of motion. Patients' symptoms are usually intermittent and related to exertion. Patients almost always reveal a history of overuse injury, and some patients recall an additional single traumatic insult to the elbow. Most patients have a history of throwing activities or play a racquet sport. Junior-level (eg, Little League) and high-school athletes are particularly vulnerable to OCD of the elbow. Chronic valgus compression from their sports, combined with their immature articular surfaces, predisposes them to capitellar lesions. Patients with loose body lesions may report catching, locking, and giving-way.

Upon physical examination of a patient with elbow OCD, joint effusion, crepitus, and generalized tenderness may be noted.

The age of the patient is critical to the determination of whether a patient with knee OCD requires surgical intervention and, if so, the timing of that operation. Operative intervention is warranted in a child with knee OCD if symptoms have persisted for 6-12 months, if radiographic indices predict inadequate healing with conservative measures, if skeletal maturity will occur within 6 months, or if loose bodies are present. Earlier operative intervention is considered appropriate in an adult with knee OCD. In an adult with knee OCD, the decision to operate should rely more heavily on history and physical examination findings. If the physician feels that nonoperative management is unlikely to be successful, surgical intervention should be pursued.

Surgery is indicated in all patients with ankle OCD who have lateral talar lesion fragments that are completely detached but remain within the underlying crater bed (stage III). Symptomatic patients with medial stage III talar lesions require surgery. Loose body lesions (stage IV lesions) on both the medial and lateral side require surgical intervention.

The natural history of elbow OCD is not well understood, and therefore, the indications for surgery are controversial. Progressive joint contracture, unresolved symptoms after conservative treatment, and fixed contracture of more than 10° with elbow pain are common indications for surgical intervention. Indications for surgery include locking or catching in the elbow associated with pain and swelling. Pain with locking is often noted.

Finally, all patients with symptomatic lesions in whom conservative management fails should be offered surgery. Of course, radiographic findings must be correlated with other clinical features. Old, asymptomatic OCD may be an incidental finding in a patient with another cause for the symptoms. In addition, asymptomatic patients with lesions in weight-bearing joints should be considered for surgery because these lesions may lead to early degenerative joint disease.

Relative contraindications for osteochondral autografts include age older than 45 years, obvious chondromalacia of the articular cartilage surrounding the defect, and abnormal mechanical alignment or instability of the affected joint.

No laboratory studies are indicated in the workup of osetochondritis dissecans (OCD). Imaging studies, typically beginning with plain radiographs and often progressing to magnetic resonance imaging (MRI) scans, are used to confirm the diagnosis and guide treatment. Computed tomography (CT) scanning may be helpful in preoperative planning and in guiding treatment when MRI is not available or is contraindicated.Some authors advocate the use of arthroscopy as a diagnostic tool in addition to MRI prior to invasive procedures.

Imaging techniques used in the evaluation of osteochondritis dissecans (OCD) include the following:

• Plain radiography
• Scintigraphy
• Magnetic resonance imaging (MRI)
• Ultrasound

Radiography

Radiographic evaluation is an appropriate first-line investigation for OCD.[9] When detectable, an osteochondral lesion appears as lucency in the articular epiphysis. However, patients with very early lesions may have normal radiographic findings. In OCD in the knee, a notch or tunnel posteroanterior radiograph is the best way to visualize a lesion in the medial femoral condyle. Lateral and anteroposterior radiographs are also helpful in identifying OCD on the condyles.

See the images below.

Scintigraphy

Technetium bone scintigraphy is an important tool for evaluating OCD. The degree of osseous uptake is an important indicator of potential healing of the osteochondral fragment. The greater the uptake, the higher the apparent osteoblastic activity and the greater the likelihood for healing with conservative, as opposed to surgical, management. Some authors advocate the use of serial technetium imaging to stratify patient prognosis and guide treatment. Technetium imaging may also reveal occult bilateral involvement.

Magnetic resonance imaging

MRI is useful in the evaluation of patients with OCD (see the images below). It permits visualization of loose bodies and the degree of displacement. Lesions that appear normal on standard radiographs may be detected using MRI. MRI also permits determination of the fluid interfaces and the integrity of the articular surfaces. MRI is useful in preoperative planning to determine whether the fragment is detached and if so, to what degree. Intra-articular injection of gadolinium may be considered because it increases the sensitivity and specificity of MRI findings.[10, 11, 9, 12]

Kijowski et al retrospectively compared the sensitivity and specificity of previously described MRI criteria for the detection of instability in patients with juvenile or adult OCD of the knee, with arthroscopic findings as the reference standard. Separately, previously described MR imaging criteria for detection of OCD instability were 0-88% sensitive and 21-100% specific for juvenile OCD lesions and 27-54% sensitive and 100% specific for adult OCD lesions. When used together, the criteria were 100% sensitive and 11% specific for instability in juvenile OCD lesions and 100% sensitive and 100% specific for instability in adult OCD lesions. The authors concluded from their findings that previously described MR imaging criteria for OCD instability have high specificity for adult but not juvenile lesions of the knee.[13]

Ultrasound

Sonography has been used to evaluate OCD of the knee and humeral capitellum. The advantages of sonography are lower cost than MRI and CT scanning, and dynamic scanning with motion of the affected joint. When performed by an experienced practitioner, ultrasonography may be an appropriate examination for evaluation of the humeral capitellum.

OCD of the knee

Therapy for osteochondritis dissecans of the knee is guided in large part by the age of the patient. Symptomatic lesions in children, or skeletally immature patients, who do not have loose bodies upon radiographic examination should initially be treated with conservative measures for 3 months. Conservative treatment in these patients includes limitation of activity and protected weight bearing to allow healing and prevent further displacement. Children should be offered a knee immobilizer during this time to limit the stress at the lesion.

Full activity may be permitted once the patient has no subjective reports of pain, normal physical examination findings, and radiographic evidence of healing. After 3 months, patients who are still symptomatic or whose repeat radiographs do not show improvement should be offered surgery. Earlier surgical intervention should be considered for lesions in children who are approaching physeal closure. Adults may also be given a trial of conservative treatment for knee OCD; however, they are less likely to improve without surgical intervention. Therefore, in adults, the threshold for surgery should be lower.

Incidental findings in asymptomatic patients with osteochondral lesions should be followed with repeat radiography every 4-6 months until the lesion has healed or until skeletal maturity is achieved. If the patient remains asymptomatic at skeletal maturity and the radiographic findings have not progressed, the patient may be reassured that no further treatment is indicated.

OCD of the ankle

Therapy for OCD of the ankle is guided primarily by two considerations, the location of the lesion and the radiographic findings. Patients with medial or lateral lesions and normal radiographic findings or radiographic findings that reveal only a partially detached osteochondral fragment may be treated conservatively. Conservative treatment in these patients includes immobilization of the limb in a cast or brace and no weight bearing for 6-12 weeks. Patients with a medial lesion and radiographic findings of a completely detached fragment that remains in the underlying crater bed may also be treated with 6 months of conservative care. However, symptomatic patients with a lateral lesion and radiographic findings of a completely detached fragment that remains in the underlying crater bed require surgical intervention.

OCD of the elbow

The natural history of OCD of the elbow is not well understood. Treatment of severe lesions is typically surgical; however, the results of surgery are often suboptimal, and patients are advised to expect some limitation of range of motion and possibly function after surgery. Therefore, in patients with mild-to-moderate and, possibly, severe disease, conservative therapy consisting of avoidance of the offending activity and immobilization of the elbow joint seems reasonable if the growth plates are open. The best therapy for this difficult population of patients may be early detection and prevention by avoidance of the offending activity.

In a study of 317 pediatric patients with a total of 334 OCD lesions, 35% progressed to surgery. Progression to surgery did not differ significantly between sexes with OCD of any joint, but did strongly correlate with patient age for OCD of the knee, elbow, and ankle. Progression to surgery in those cases was 8.2 times more likely in patients who were 12 to 19 years old at the time of diagnosis than in those 6 to 11 years old.[14]

Surgical options include the following[15, 16] :

• Arthroscopic subchondral drilling, to create channels that link the subchondral bone to the fragment
• Arthroscopic debridement and fragment stabilization
• Arthroscopic excision, curettage, and drilling
• Open removal of loose bodies, reconstruction of the crater base, mosaicplasty for fragment healing, and potential replacement with fixation
• Autologous chondrocyte transplantation
• Radical removal of sclerotic bone with bone grafting of the defect and autologous chondrocyte transplantation (ie, sandwich technique)

The decision for a given surgical procedure is based on findings from the preoperative evaluation. Patients should undergo preoperative MRI to better define the lesion. Some authors advocate the use of arthroscopy as a diagnostic tool in addition to MRI prior to more invasive procedures.

Patients with indications for surgery and lesions less than 3 cm in diameter should be offered arthroscopic intervention in the form of subchondral drilling and, possibly, debridement and fragment stabilization. Bone grafting may be required.

Patients with lesions 3 cm or greater in diameter or patients with multiple loose bodies may have their lesions fixed and replaced through an open procedure. Patients may also be offered autologous chondrocyte transplantation or mosaicplasty.

Patients with lesions 8 cm or greater in diameter may be offered radical removal of sclerotic bone with bone grafting of the defect and autologous chondrocyte transplantation (sandwich technique).

Arthroscopic subchondral drilling

Multiple perforations of the lesion are made using Kirschner wires. If the patient has open physes, care must be taken to avoid penetrating too deeply into the physis.

Arthroscopic debridement and stabilization using bioabsorbable nails or pins, versus nonabsorbable screw fixation

A bioresorbable bone fixation nail (eg, SmartNail) tip is used on the arthroscopic handle and inserted into the top of the fragment. Care must be taken to align the fracture before fixing it with Kirschner wires. The hole should be drilled through the fragment to the desired depth and screwed into place. If necessary, multiple pins may be placed for greater fixation. However, the pins should be placed at an angle and not parallel to one another.

Nonabsorbable screws (eg, Acutrak or Herbert screws) may be used in larger lesions with a firm crater. However, these generally must be removed after healing, which can be difficult. Screw removal is made easier if screws with reverse cutting threads (eg, Synthes 4-mm cannulated screws) are used.

Barrett et al reported that headless metal compression screws, which can be left in place, provide a satisfactory union rate for treatment of unstable osteochondritis dissecans of the femoral condyles in patients who are skeletally mature. At a mean of 31 months postoperatively (range, 2-262 months), fragment union was observed in 18 of 22 knees (82%).[17]

If bone loss is significant, cancellous bone grafting may be required.

Arthroscopic excision, curettage, and drilling

The lesion may be arthroscopically excised and the crater debrided and drilled to promote vascularity and healing.

Open removal of loose bodies, reconstruction of crater base, and replacement with fixation

The base of the crater is drilled to enhance vascularity. The fragment is trimmed, replaced, and securely fixed with Kirschner wires. The Kirschner wires are later removed in a retrograde fashion.

Fixation with bone pegs

Autogenous matchstick-sized strips of corticocancellous bone graft are used for internal fixation of the OCD lesion to the site of the defect. The cancellous bone graft is packed as needed into the lesion to restore articular congruity.

Autologous osteochondral mosaicplasty

Cylindrical osteochondral grafts from the minimal weight-bearing periphery are arthroscopically removed and transplanted into prepared defects in the weight-bearing or affected area. Combinations of the different graft sizes are used to allow a greater filling rate. Fibrocartilage grouting, stimulated by abrasion arthroplasty or sharp curettage at the base of the defect, completes the new surface.

Autologous chondrocyte transplantation

Chondrocytes are arthroscopically harvested and cultured in a cell culture laboratory for 2-3 weeks. During chondrocyte transplantation, care is taken to not provoke bleeding from the osseous bottom of the defect during debridement. Cultured cells are injected into the defect, which is covered with a periosteal flap. This technique is required for extensive defects in which other treatments have failed.

Radical removal of sclerotic bone with bone grafting of the defect and autologous chondrocyte transplantation (sandwich technique)

The defect is excised to the normal surrounding cartilage, and the sclerotic bone is excavated down to the bleeding cancellous bone. The osseous defect is filled with cancellous bone to the subchondral bone plate, and a periosteal flap is harvested and used to secure the graft. A second periosteal flap is then used for the autologous chondrocyte transplantation, which is performed as previously described.

Postoperative images of osteochondritis dissecans are shown below:

Following arthroscopic subchondral drilling without debridement or fixation, the affected joint is immobilized and a motion-restricting brace is prescribed. Patients are also instructed to be bearing weight on a toe-touch basis until signs of healing are evident upon radiographic examination. Once signs of healing are evident, patients should perform range-of-motion exercises for 20 minutes, 3 times per day. A similar rehabilitation protocol should be used after fixation with bone pegs.

Following all other surgeries, immobilization is not necessary. Continuous passive motion is administered on the same day as surgery and continued for 48 hours. Rehabilitation exercises with emphasis on limb function and muscle recruitment are initiated after 48 hours and are continued for 8 weeks. Weight bearing is gradually introduced into the patient's rehabilitation schedule, and the patient is progressed to full weight bearing by 6-8 weeks.

Surgical complications may include infection and neurovascular injuries, but these complications are particularly rare in these procedures.

The natural history and prognosis with different treatments vary depending on the age of the patient, the joint affected, and the stage of the lesion. Still, treatment and prognosis remain somewhat controversial because of the relative lack of clinical exposure by most physicians to patients with osteochondritis dissecans. In addition, the literature often describes juvenile and adult OCD as the same condition. Nonetheless, data suggest certain definite trends.[18, 19]

OCD of the knee

Juvenile OCD in the knee, without a loose body lesion, frequently heals with conservative therapy. Successful results have been reported in as many as 94% of these patients when treated with casting or bracing for 4 months. After conducting a systematic review of 27 studies with a total of 908 conservatively treated knees, Andriolo et al concluded that restriction of strenuous activity appeared to have favorable outcomes, whereas there was no evidence of benefit from physical instrumental therapy, immobilization, or weightbearing limitation.[3]  

Adult OCD in the knee, by contrast, rarely responds to conservative measures. One study examined patients who had knee OCD after physeal closure and found that 38 of 48 patients had gonarthrosis at 33-year follow-up.[15, 20, 21]

OCD of the ankle

Juvenile patients with ankle OCD seem to respond significantly better to conservative treatment than do their adult counterparts. In one study, juvenile ankle OCD treated with conservative care had a 95% success rate. Another study reported an 82% successful rate for juvenile ankle OCD with conservative therapy.

A review of 14 clinical studies evaluating 201 patients without distinction between juvenile and adult ankle OCD found that only 45% of patients responded successfully to conservative management. However, in addition to combining juvenile and adult patients, these studies did not provide consistent criteria for conservative treatment; they also did not consistently delineate what conservative treatment was provided. If adult patients are appropriately selected (stage I and II lesions and stage III medial lesions) and conservative care is appropriately provided, the successful response rate is likely to be significantly higher.[22]

In a study of juvenile patients with ankle OCD who required surgical intervention, 40% had good results, 53% had fair results, and 7% had poor results. Adult ankle OCD seems to respond better than juvenile ankle OCD when surgical intervention is required. One prospective study found excellent or good results in 82% of adult patients treated with arthroscopic excision, curettage, and drilling of the ankle OCD defect at a mean follow-up of 4.8 years.

OCD of the elbow

Few long-term studies have evaluated elbow OCD. One study evaluated five female gymnasts aged 11-13 years. Three of these gymnasts were treated conservatively, and two underwent arthroscopic removal of a loose body. Four continued to compete in gymnastics at the 3-year follow-up. Another study, however, evaluated 7 female gymnasts at an average age of 13.3 years. All underwent surgery, and all lost extension, with only one continuing to compete in the sport.[2]

Adult patients with elbow OCD may respond better to surgical treatment. One study evaluated 35 adult athletes treated with arthroscopic surgery and reported successful results in 90%. However, although these patients did not lose function, many of them did lose up to 10° of extension.[2]

Surgical intervention

Pascual-Garrido et al examined the outcomes of surgical procedures for osteochondritis dissecans in 46 adult patients (48 knees), with patients ranging in age from 20 to 49 years. Patients who were treated with surgical cartilage procedures showed durable function and symptomatic improvement at a mean of 4 years follow-up. Patients treated with arthroscopic reduction and internal fixation and loose-body removal had greater improvement in outcome scores than those treated with an osteochondral allograft. Seven knees required revision procedures at a mean follow-up of 14 months.[23]

Outcomes with the following procedures are described below[1, 2, 7, 20, 21, 22] :

• Arthroscopic subchondral drilling
• Fixation with bone pegs
• Fixation with bioabsorbable implants
• Autologous chondrocyte transplantation
• Autologous osteochondral mosaicplasty

Arthroscopic subchondral drilling

Arthroscopic subchondral drilling in patients with juvenile OCD in the knee yields an approximate 80% success rate at 1-year follow-up. In adult OCD in the knee, arthroscopic subchondral drilling appears to be less effective, with approximately 70% success.

Arthroscopic drilling with fixation in patients with knee OCD yields good or excellent results in approximately 94% of patients. Open removal of loose bodies, reconstruction of the crater base, and replacement with fixation yield a success rate of approximately 70%.

Adachi et al evaluated the functional and radiographic outcome of retroarticular drilling without bone grafting in 12 patients with juvenile osteochondritis dissecans after 6 months of unsuccessful nonoperative treatment. The mean Lysholm score significantly improved postoperatively (from 72.3 to 95.8). All lesions except 1 healed after retroarticular drilling, and healing was achieved at a mean of 4.4 months on plain radiographs and 7.6 months on magnetic resonance imaging.[24]

Fixation with bone pegs

Fixation with bone pegs had 100% effectiveness in one study of 17 patients with knee OCD. Another study in a military population evaluated fixation with bone pegs with supplementary Kirschner-wire fixation and found that 47 of 54 patients were able to return to active military duty.

Fixation with bioabsorbable implants

Tabaddor et al evaluated the efficacy and safety of poly 96L/4D-lactide bioabsorbable copolymer fixation for unstable OCD in 24 adolescents (mean age, 14.4 y). Plain films at an average of 19.2 months after surgery showed interval healing in 9 patients, no significant change in 1, complete healing in 13, and loose bodies with no interval healing in 1. MRIs showed interval healing in 16 of 17 knees at a mean follow-up of 22.4 months.[25]

Autologous chondrocyte transplantation

Autologous chondrocyte transplantation for the treatment of OCD lesions of the femoral condyle was found to yield good results at 2-year follow-up in 52 of 53 patients.[21] In one study, autologous chondrocyte transplantation for ankle OCD in adults achieved a 100% effectiveness rate in all 8 patients treated, with a mean follow-up of 17.6 months.[22]

Another prospective study evaluated the effectiveness of autologous osteochondral grafts in adult ankle OCD and found excellent results in 82% of patients. This study found that patients younger than 45 years, patients who do not smoke, and patients with active lifestyles had the best chance for optimal outcome.

An additional consideration for autologous chondrocyte transplantation is that preparing the cells for implantation is an expensive process. Some insurers may not offer coverage for this method because of the expense.

Lyon et al reviewed 11 cases of children with OCD of the knee who were treated with a fresh osteochondral allograft. The study concluded that the allografts restored short-term function in patients in whom standard treatment was unsuccessful.[26]

Sacolick and colleagues reviewed the outcomes from 179 patients and found a failure rate of 8.2%. Complications were reported in 15.6% of cases. Males, active patients, smaller lesion sizes, and younger age at the time of surgery were positive prognostic factors.[27]

Autologous osteochondral mosaicplasty

Autologous osteochondral mosaicplasty was found to be 94% effective for OCD lesions requiring surgery in the femoral condyle and 88% effective for OCD lesions requiring surgery in the talus. However, a prospective, randomized study that directly compared autologous chondrocyte implantation with mosaicplasty for OCD lesions in the knee found that autologous chondrocyte implantation had significantly better results for lesions in the medial femoral condyle, lateral femoral condyle, and patella. Although mosaicplasty was effective for medial and lateral femoral condyle lesions, it was inferior to autologous chondrocyte implantation. For patellar lesions, the study showed no effectiveness for mosaicplasty.[20]

Autologous chondrocyte implantation and mosaicplasty are still relatively new procedures. Their initial results are promising; however, further data are needed before firm recommendations can be made. This is especially true with regard to their use in ankle and elbow OCD. Future research will also need to differentiate responses between juvenile and adult OCD because the two patient populations affected by these conditions seem to respond differently to various treatments.