Orthopaedic Surgeon
Osteochondral Defect
What is an Osteochondral Defect or Lesion?
An osteochondral defect is a lesion of the articular cartilage and can involve the subchondral bone below the cartilage. There are many types of osteochondral lesions and defects. A special type of these lesions is also referred to as osteochondritis dissecans or OCD lesion. These are more common in children. Articular cartilage injuries, however, can occur in all age groups.
The articular cartilage is the special tissue layer that makes up the contact surface of joints. It is very smooth, but also delicate. If injured, it is very difficult for the body to heal cartilage injuries. The cartilage is supported by underlying bone. When the bone becomes damaged or does not receive the appropriate blood supply to the tissues a person can also develop a cartilage lesion or defect.
What Causes an Osteochondral Lesion?
MRI image with the arrow pointing at an OCD lesion in the femur or thigh bone of the knee.
There are multiple causes for cartilage lesions including trauma, poor blood supply to the bone and cartilage, and even genetics may play a role in the development of cartilage lesions. There are two types of cartilage lesions--juvenile, which affects younger patients and adult, which affects patients that are finished growing.
How are OCD Lesions Treated?
When an OCD lesions is diagnosed by xray or MRI we typically begin with a treatment of non-weight bearing. This allows the joint to rest while the lesion resolves on its own. Stable lesions in children--they have open growth plates and better potential for healing--have a better change for success with this treatment. Larger lesions or persistent lesions in older patients may need surgical stimulation to promote healing. This can commonly be accomplished with arthroscopic surgery or small pen incisions to access the joint and defect.
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A video demonstrating a drilling/microfracture surgery can be found here.
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For medium sized lesions, we have multiple treatments including several biologic treatments that attempt to stimulate cartilage-like tissue healing. When a cartilage defect or lesion is very large (for example > 1cm in size), we may consider cutting out the lesion and replacing it with a plug of bone and cartilage from another part of the joint that is not involved in joint motion. This treatment is known as an osteochondral transplant. The plug can be from your own tissue and is known as an "autograft," or it can come from a donor and is known as an "allograft."
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A video demonstrating an autograft transplant surgery can be found here.
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There is limited data available for return to athletics following osteochondral allograft treatment of knee lesions. Krych et al. studied 43 athletes with an average age of 32.9 years (range, 18–49). At an average of 2.5-year follow-up, 79% of athletes fully returned to pre-injury activity levels, while another 9 % returned to sports but with limitations. These athletes returned to sports at an average of 9.6 months post-operatively. Age greater than 25 years and pre-operative duration of symptoms greater 12 months predicted a lower likelihood of return to athletics.
This drawing representing a camera scope viewing the knee lesion in the femur while an arthroscopic awl is used to microfracture the lesions to stimulate healing. Image from wikicommons.
Many of the cartilage treatments we use depend on if the lesion is "Contained" or "Not Contained." In other words, is the lesion at the edge of the cartilage and bone border or in the central area of the joint and surrounded like an island by cartilage.
THE CARTILAGE TREATMENT LADDER
Total Joint Replacement
Weight Bearing ~ First few days
Recovery: ~1 year+
Osteochondraol Allograft (Cadaver Tissue) Transplant (OCA)
Protected Weight Bearing ~6 weeks
Recovery ~8 months to 1 year
Osteochondral Autograft (Your Own Tissue) Transplant (OAT)
Protected Weight Bearing ~6 weeks
Recovery ~8 months to 1 year
Particulated Donor Cartilage
Protected Weight Bearing ~2-6 weeks
Recovery ~6-9 months
Autologous Chondrocyte Implantation (ACI)
2 Surgeries-1 to harvest and 1 to implant
Protected Weight Bearing ~6 weeks
Recovery ~9 months - 1 year
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Bone Marrow Stimulation - Microfracture (with Scaffold)
Knee Protect Weight Bearing ~4 weeks
Kneecap Protected WB ~ 2 weeks
Recovery ~3-6 months
Remove Loose Body, and/or Chondroplasty
Weight Bearing ~Immediate
Recovery ~2-4 weeks
More Invasive
Longer Recovery
Less Invasive
Faster Recovery
Knee Lesion Considerations
CONDYLES
<1cm, superficial: chondroplasty
~1cm, younger than 30: OATs
~1cm, older than 30: OCAs
~1-2cm: Microfracture with Scaffold
ACI must have full-thickness cartilage margins
TROCHLEA
Up to ~2cm in trochlea: Cartilage patch
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PATELLA
Microfracture versus Particulated Cartilage
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Consider: Open versus scope, number of surgeries, recovery time, time to obtain tissue, tissue source, weight bearing and future procedures...
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Once you start on the ladder, most patients take multiple steps, in other words, more than one surgery. Please talk with Dr. Skelley to determine the best treatment plan for your injury.
References
1. Krych AJ, Robertson CM, 3rd Williams RJ. Cartilage study group. Return to athletic activity after osteochondral allograft transplantation in the knee. Am J Sports Med. 2012;40(5):1053–9. doi: 10.1177/0363546511435780.
2. Torrie AM, Kesler WW, Elkin J, Gallo RA. Osteochondral allograft. Current Reviews in Musculoskeletal Medicine. 2015;8(4):413. doi:10.1007/s12178-015-9298-3.
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