We reviewed 13 cases of osteochondritis dissecans of the patella followed-up for 18 months to 19 years. Two were treated conservatively with excellent results, and 11 by operation with six excellent, four good and one fair result. There was complete radiographic healing of the defect in 10 cases and partial healing in three. The size of the osteochondritic lesion appeared to be of prognostic significance. Osteochondritis dissecans of the patella is the result of repeated minor injuries to the articular surface. Operation is indicated for persistent pain, intra-articular loose bodies and subchondral sclerosis; excision of the fragment and curettage of the crater, with or without drilling, is recommended

Thirty patients with osteochondritis dissecans of the ankle have been followed up for an average of 21 years. The histories and radiographs were reviewed, and it was found that most patients had only minor radiographic changes and symptoms. Two patients had developed osteoarthritis but in only one was this severe. Osteochondritis dissecans in the ankle thus seems to differ from the same lesion in the knee where late osteoarthritis often occurs. Two lesions were located on the joint surface of the distal tibia, a site not previously reported

Osteochondritis Dissecans (OCD) is a condition for which the aetiology remains unknown. It affects subchondral bone and secondarily its overlying cartilage and is mostly found in the knee. It can occur in adults, but is generally identified when growth remains, when it is referred to as juvenile OCD. As the condition progresses, the affected subchondral bone separates from adjacent healthy bone, and can lead to demarcation and separation of its associated articular cartilage. Any symptoms which arise relate to the stage of the disease. Early disease without separation of the lesion results in pain. Separation of the lesion leads to mechanical symptoms and swelling and, in advanced cases, the formation of loose bodies.

Early identification of OCD is essential as untreated OCD can lead to the premature degeneration of the joint, whereas appropriate treatment can halt the disease process and lead to healing. Establishing the stability of the lesion is a key part of providing the correct treatment. Stable lesions, particularly in juvenile patients, have greater propensity to heal with non-surgical treatment, whereas unstable or displaced lesions usually require surgical management.

This article discusses the aetiology, clinical presentation and prognosis of OCD in the knee. It presents an algorithm for treatment, which aims to promote healing of native hyaline cartilage and to ensure joint congruity.

Take home message: Although there is no clear consensus as to the best treatment of OCD, every attempt should be made to retain the osteochondral fragment when possible as, with a careful surgical technique, there is potential for healing even in chronic lesions

Cite this article: Bone Joint J 2016;98-B:723–9.

Six cases of osteochondritis dissecans patellae have been studied in five patients in an attempt to clarify the aetiology and prognosis. Assessment of the results of treatment was performed using a standard protocol. The thirty-four previous case reports in the literature are reviewed. In four of the five patients symptoms began after flexing the knee under load and three showed patellar subluxation on tangential radiographs. Thus, repetitive shearing stress on the patellar surface is thought to be an important aetiological factor. The indication for operation is a loose osteochondral fragment either wholly or partly detached from the articular surface of the patella. Vertical excision of the affected area of articular cartilage with drilling of the underlying bone gave two "good" and two "excellent" results. Healing of the drilled area and maintenance of the cartilage space was seen in radiographs of all four cases so treated. This simple method of treatment, which probably causes filling of the defect in the surface by fibrocartilage, is recommended.

The treatment of osteochondritis dissecans (OCD) in children and adolescents is determined by the stability of the lesion and the state of the overlying cartilage. MRI has been advocated as an accurate way of assessing and staging such lesions. Our aim was to determine if MRI scans accurately predicted the subsequent arthroscopic findings in adolescents with OCD of the knee.

Some authors have suggested that a high signal line behind a fragment on the T2-weighted image indicates the presence of synovial fluid and is a sign of an unstable lesion. More recent reports have suggested that this high signal line is due to the presence of vascular granulation tissue and may represent a healing reaction.

We were able to improve the accuracy of MRI for staging the OCD lesion from 45% to 85% by interpreting the high signal T2 line as a predictor of instability only when it was accompanied by a breach in the cartilage on the T1-weighted image. We conclude that MRI can be used to stage OCD lesions accurately and that a high signal line behind the OCD fragment does not always indicate instability.

We recommend the use of an MRI classification system which correlates with the arthroscopic findings.

Twenty-two knees with osteochondritis dissecans diagnosed before skeletal maturity were followed prospectively into middle age: 32% had radiographic evidence of moderate or severe osteoarthritis at an average follow-up of 33.6 years; only half had a good or excellent functional result. We found that osteoarthritis was more likely to occur if the defect was large or affected the lateral femoral condyle.

We reviewed lesions of the femoral condyles seen in 5,000 knee arthroscopies, recording the findings and the age and sex of the patients. We were able to distinguish the characteristics of developing and late osteochondritis dissecans, acute and old osteochondral fractures, chondral separations, chondral flaps and idiopathic osteonecrosis, and suggest that these are separate distinct conditions. Haemarthrosis was associated only with acute osteochondral fractures. The characteristic feature of osteochondritis dissecans was an expanding concentric lesion at the 'classical' site on the medial femoral condyle which appeared during the second decade of life and progressed to a concave steep-sided defect in the mature skeleton. Caffey's (1958) classification of epiphyseal dysplasias could not be applied to osteochondritis dissecans, which appeared to have a gradual onset without acute trauma. Much of the controversy about the cause of osteochondritis dissecans is the result of imprecise nomenclature.

Thirty-five cases of osteochondritis dissecans of the talus, operated on between 1950 and 1978, were studied. Twenty-four were available for follow-up an average of 47 months later. Three standard surgical approaches were used, and the osteochondritic fragment removed. In some cases the base of the defect was drilled. Good results were obtained in 15 patients, and fair in nine. There were no poor results. It was concluded that the defect is caused by trauma; that early operation gives the best results, 12 months being the critical delay time; that drilling the base of the defect improves results; and that the sex of the patient and the location of lesion are of little significance.

In 1887, Konig claimed that loose bodies in the knee joints of young persons had three causes: (1) very severe trauma; (2) lesser trauma causing contusion and necrosis; and (3) minimal trauma acting on an underlying lesion-for which he suggested the name osteochondritis dissecans. His thesis has stood the test of time. We still confuse the second and third categories but osteochondritis dissecans has been identified as an ossification defect.

The purpose of this study was to evaluate the long-term functional and radiological outcomes of arthroscopic removal of unstable osteochondral lesions with subchondral drilling in the lateral femoral condyle. We reviewed the outcome of 23 patients (28 knees) with stage III or IV osteochondritis dissecans lesions of the lateral femoral condyle at a mean follow-up of 14 years (10 to 19). The functional clinical outcomes were assessed using the Lysholm score, which improved from a mean of 38.1 (sd 3.5) pre-operatively to a mean of 87.3 (sd 5.4) at the most recent review (p = 0.034), and the Tegner activity score, which improved from a pre-operative median of 2 (0 to 3) to a median of 5 (3 to 7) at final follow-up (p = 0.021). The radiological degenerative changes were evaluated according to Tapper and Hoover’s classification and when compared with the pre-operative findings, one knee had grade 1, 22 knees had grade 2 and five knees had grade 3 degenerative changes. The overall outcomes were assessed using Hughston’s rating scale, where 19 knees were rated as good, four as fair and five as poor.

We found radiological evidence of degenerative changes in the third or fourth decade of life at a mean of 14 years after arthroscopic excision of the loose body and subchondral drilling for an unstable osteochondral lesion of the lateral femoral condyle. Clinical and functional results were more satisfactory.

Osteochondritis dissecans occurring bilaterally in either the knees or the elbows is recorded in four members of one family. The suggestion is supported that the underlying pathology may be developmental, resulting in a form of localised osteochondrodystrophy

1 . Two cases of osteochondritis dissecans after Legg-Calvé-Perthes' disease observed for thirty years are described. 2. Osteochondritis dissecans of the hip can remain in an apparently unchanged state for many years and in these two patients is associated with excellent function, not requiring surgery

We describe two cases of osteochondritis dissecans (OCD) affecting both femoral condyles in the same knee. The patients presented with recurrent episodes of pain and swelling, but these were initially thought to be ‘growing pains’. Eventually, a delayed diagnosis of bicondylar OCD was established and both patients were referred for further management. After assessing the extent of the disease on MRI, matrix-induced autologous chondrocyte implantation was performed to treat the defects of the lateral condyle in each case, with a plan to address the medial defects at a later stage. Proposed theories on the aetiology of the condition and available methods of treatment are discussed. A diagnosis of OCD should be considered in young patients with persistent knee pain and effusions, and MRI is the investigation of choice for early detection.

Autologous chondrocyte implantation (ACI) and mosaicplasty are methods of treating symptomatic articular cartilage defects in the knee. This study represents the first long-term randomised comparison of the two techniques in 100 patients at a minimum follow-up of ten years. The mean age of the patients at the time of surgery was 31.3 years (16 to 49); the mean duration of symptoms pre-operatively was 7.2 years (9 months to 20 years). The lesions were large with the mean size for the ACI group being 440.9 mm² (100 to 1050) and the mosaicplasty group being 399.6 mm² (100 to 2000). Patients had a mean of 1.5 previous operations (0 to 4) to the articular cartilage defect. Patients were assessed using the modified Cincinnati knee score and the Stanmore-Bentley Functional Rating system. The number of patients whose repair had failed at ten years was ten of 58 (17%) in the ACI group and 23 of 42 (55%) in the mosaicplasty group (p < 0.001).

The functional outcome of those patients with a surviving graft was significantly better in patients who underwent ACI compared with mosaicplasty (p = 0.02).

We attempted to characterise the biological quality and regenerative potential of chondrocytes in osteochondritis dissecans (OCD). Dissected fragments from ten patients with OCD of the knee (mean age 27.8 years (16 to 49)) were harvested at arthroscopy. A sample of cartilage from the intercondylar notch was taken from the same joint and from the notch of ten patients with a traumatic cartilage defect (mean age 31.6 years (19 to 52)). Chondrocytes were extracted and subsequently cultured. Collagen types 1, 2, and 10 mRNA were quantified by polymerase chain reaction. Compared with the notch chondrocytes, cells from the dissecate expressed similar levels of collagen types 1 and 2 mRNA. The level of collagen type 10 message was 50 times lower after cell culture, indicating a loss of hypertrophic cells or genes. The high viability, retained capacity to differentiate and metabolic activity of the extracted cells suggests preservation of the intrinsic repair capability of these dissecates. Molecular analysis indicated a phenotypic modulation of the expanded dissecate chondrocytes towards a normal phenotype. Our findings suggest that cartilage taken from the dissecate can be reasonably used as a cell source for chondrocyte implantation procedures.

Repeated trauma to the radial head may be one of the causative factors in the genesis of osteochondritis dissecans of the capitellum. We measured the force, contact area and pressure across the radiocapitellar articulation of the elbow before and after radial shortening osteotomy in five fresh-frozen cadaver upper limbs with loads of 45, 90 and 135 N, respectively. Measurements were made on pressure-sensitive film placed in the radiocapitellar articulation with the forearm in the supinated, neutral and pronated positions before and after radial shortening. Radial shortening significantly reduced the mean force and contact area across the radiocapitellar articulation in all positions of the forearm.

Autologous chondrocyte implantation (ACI) is used widely as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum-cover technique include the use of porcine-derived type I/type III collagen as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) using a collagen bilayer seeded with chondrocytes. We have performed a prospective, randomised comparison of ACI-C and MACI for the treatment of symptomatic chondral defects of the knee in 91 patients, of whom 44 received ACI-C and 47 MACI grafts.

Both treatments resulted in improvement of the clinical score after one year. The mean modified Cincinnati knee score increased by 17.6 in the ACI-C group and 19.6 in the MACI group (p = 0.32). Arthroscopic assessments performed after one year showed a good to excellent International Cartilage Repair Society score in 79.2% of ACI-C and 66.6% of MACI grafts. Hyaline-like cartilage or hyaline-like cartilage with fibrocartilage was found in the biopsies of 43.9% of the ACI-C and 36.4% of the MACI grafts after one year. The rate of hypertrophy of the graft was 9% (4 of 44) in the ACI-C group and 6% (3 of 47) in the MACI group. The frequency of re-operation was 9% in each group.

We conclude that the clinical, arthroscopic and histological outcomes are comparable for both ACI-C and MACI. While MACI is technically attractive, further long-term studies are required before the technique is widely adopted.