Osteochondritis Dissecans of the Knee: How Should We Treat?

By: Justin W. Arner, M.D.

Osteochondritis dissecans (OCD) of the knee was first noted in 1888 as inflammation of the bone-cartilage interface.1 Unfortunately, we still do not know the condition’s cause, but Franz Konig was remarkably accurate in his description. Since this initial description, we have learned that stability of the bone-cartilage interface is key in determining treatment and outcome. An MRI is the best way to determine stability of the bony lesion based on the amount of fluid under the lesion. The knee is the most common site for an OCD lesion; however, these lesions also occur in the ankle, elbow, shoulder and hip.

 

OCD lesions typically occur in young patients with varying clinical presentations based on bony stability. Age, sex and race play a role in those with open physes (juvenile OCD). In a study by Kessler et al., incidence increased in ages 12-16. Male sex, African American race and sports participation were all risk factors for development. The age at diagnosis is crucial because those with open physes have a better chance of healing an OCD lesion.


Patients typically report pain in stable lesions and commonly experience swelling, as well as mechanical issues like clicking and locking in unstable lesions. Physical examination should include evaluating effusion as well as tenderness over the femoral condyle. The most common location for a lesion is the lateral aspect of the medial femoral condyle (MFC); therefore, one may have tenderness over the anteromedial knee while the knee is flexed. Wilson’s Sign is a maneuver where the examiner flexes the knee 30-90 degrees and internally rotates the tibia in an attempt to impinge the MFC lesion onto the tibial spine, which leads to pain. External rotation in this position will sometimes relieve pain. Unfortunately, this test historically indicates low sensitivity.3

 

Radiographs are helpful in determining the lesion’s location with 45-degree posteroanterior views, which are best for showing lesions of the femoral condyle. Both knees should be evaluated upon X-ray, as up to 29% of patients may have a bilateral lesion.4 Full leg alignment X-rays can be helpful for evaluating malalignment. Lesion stability is best determined on MRI; however, sclerosis with radiolucency can be a sign of instability. X-rays can be helpful in tracking lesion healing during follow-up.

 

MRI was shown to be ideal for diagnosis as well as determining the size and stability of OCD lesions, with 100% specificity and 92% sensitivity. Multiple grading systems were proposed based on fluid between the lesion and bone as well as the fragment’s instability, whether it be hinged or fully displaced.5 MRI can also be helpful in monitoring healing, especially in those with continued pain or concerns with activity progression. Serial X-rays are recommended for monitoring healing progress, with MRI as a supplementary option if any concerns arise regarding symptoms, examination or radiographs.

 

Treatment of OCD lesions is based on the patient’s physeal status as well as size and location. Skeletally immature patients have a higher propensity to heal lesions if they are stable on MRI. Typically, activity modification with no sports participation for three-six months is recommended. No high-level data exists regarding weight bearing or immobilization, but many surgeons do recommend this for the initial six weeks with X-ray evaluation. One systematic review found a large range in this population’s healing rates, from 10-96%.6 In our practice, we usually start with six weeks of restricted weight bearing with a brace, followed by progressive weight bearing and physical therapy. Return to sports occurs around the three-month mark if there are no concerning symptoms and X-rays show healing. Complete healing is not commonly noted on X-ray at three months, but if patients are symptom-free, progression back to sports is permitted. If there are issues such as persistent pain, swelling or no signs of healing progression, it is recommended to undergo a repeat MRI.

 

Operative treatment options of the lesion range from transarticular or retrograde drilling to arthroscopic or open fixation. If the lesion is not salvageable, transplantation options are recommended, whether it be autologous chondrocyte implantation, osteochondral autograft transplantation or osteochondral allograft transplantation. Stable lesions on MRI failing conservative treatment may be treated with drilling techniques as mentioned above, aiming to disrupt the sclerotic lesion using small k-wires to enhance blood flow and healing. Transarticular drilling is preferred, as the location is best defined and X-ray is not needed, however the cartilage is violated. Posterior femur lesions may be difficult to access. Healing rates were cited to be 85-100% with these techniques.7

 

Unstable lesions are best treated with arthroscopic or open techniques if substantial bone is still attached to the cartilaginous surface, typically at least 2-3 mm. Fibrous tissue must be debrided for a good healing surface. Fixation can be done with metallic or bioabsorbable implants. Metal screws have the advantage of stable fixation; however, it is difficult to evaluate healing on MRI. It is also very common that the screws need to be removed with a second surgery. Bioabsorbable implants avoid these issues, but implants backing out or breaking are a concern that can cause large amounts of damage to the joint. High levels of healing were shown with both techniques ranging from 92-100%.8

 

If lesions are irreparable due to lack of bone or size, transplantation options are recommended. Researchers have described a sandwich technique in patients with subchondral bone defects. In those with bone loss, autograft or allograft transplant options prove ideal and demonstrate excellent outcomes. Allograft options are typically recommended in larger defects.

 

OCD lesions are complex and idiopathic, with MRI stability and physeal status guiding treatment. Those with open and stable physes have high healing rates. Stable lesions that fail nonoperative treatment commonly respond to drilling techniques, while unstable lesions require arthroscopic or open treatment if there is sufficient bone on the cartilage. If this is not the case, typically transplantation options are best.

 

References

  1. König. "Ueber freie Körper in den Gelenken." Deutsche Zeitschrift für Chirurgie. 1888;27:90-109.
  2. Kessler, J.I., Nikizad, H., Shea, K.G., Jacobs Jr., J.C., Bebchuk, J.D., Weiss, J.M. "The Demographics and Epidemiology of Osteochondritis Dissecans of the Knee in Children and Adolescents." The American Journal of Sports Medicine. 2014;42:320-326.
  3. Zaremski, J.L., Herman, D.C., Vincent, K.R. "Clinical Utility of Wilson Test for Osteochondral Lesions at the Knee." Current Sports Medicine Reports. 2015;14:430.
  4. Chan, C., Richmond, C., Shea, K.G., Frick, S.L. "Management of Osteochondritis Dissecans of the Femoral Condyle: A Critical Analysis Review." JBJS Reviews. 2018;6:e5.
  5. Grimm, N., Danilkowicz, R., Shea, K. "OCD Lesions of the Knee: An Updated Review on a Poorly Understood Entity: Current Concept Review." Journal of the Pediatric Orthopaedic Society of North America. 2019;1.
  6. Andriolo, L., Candrian, C., Papio, T., Cavicchioli, A., Perdisa, F., Filardo, G. "Osteochondritis Dissecans of the Knee – Conservative Treatment Strategies: A Systematic Review." Cartilage. 2019;10:267-277.
  7. Bauer, K.L. "Osteochondral Injuries of the Knee in Pediatric Patients." The Journal of Knee Surgery. 2018;31:382-391.
  8. Abouassaly, M., Peterson, D., Salci, L., et al. "Surgical Management of Osteochondritis Dissecans of the Knee in the Pediatric Population: A Systematic Review Addressing Surgical Techniques." Knee Surgery, Sports Traumatology, Arthroscopy. 2014;22:1216-1224.
Scroll to top