Cartilage Defects and Osteochondritis Dissecans

Osteochondritis Dissecans or OCD is a condition that occurs when fragments of bone below the joint surface lose blood supply separate from the rest of the bone. The most common site for OCD is the knee. The most common location the knee is the lateral side of the medial femoral condyle. Although no one knows why a segment of bone should lose its blood supply, most doctors believe that it is due to repetitive trauma. OCD occurs commonly in the older child and adolescent who actively participate in sports. The theory is that the repetitive motion of the sport, like soccer, causes a small segment of the bone to fatigue and fracture under the surface. The continued micro-trauma from repetitive loading, i.e. continued running on the already injured knee prevents the defect from healing and loosens the bone fragment. The loose fragment then can cause swelling and pain. It can also occur in any age group after an acute injury. In those cases, the bone may be fractured and the fractured part of the joints surface fails to heal. The most common symptoms of OCD are pain and swelling.

OCD is usually diagnosed using X-Ray images. In a growing child, an early lesion may heal with crutches, rest and a brace or cast. If the defect is displaced or loose and/or an MRI shows fluid under it, surgery may be necessary.

If surgical intervention is necessary and the cartilage fragments have not broken loose, the surgeon may fix them in place using pins or screws that are sunk into the cartilage to stimulate new blood supply. These pins are often dissolving (bioabsorbable) and do not need to be taken out once the bone heals. If fragments are loose, the surgeon may clean the cavity to reach fresh healthy bone and attach a bone graft in position with screws. Fragments that cannot be mended are cleaned and drilled to stimulate new growth of cartilage.

Shallow Cartilage Defects, may be different from OCD and can be caused by wear and tear or arthritis. These can be treated by a technique called micro fracture. In the micro-fracture technique, the surface is drilled or “cracked” with a microscopic drill or awl to help blood and marrow get to the surface. Just like aerating the soil before seeding the lawn, the idea is to promote the formation of new fibro-cartilage. The new cartilage would then cover the surface with fresh tissue.

Loose Bodies

If the symptoms for a cartilage defect is ignored and spontaneous healing doesn’t occur, cartilage and its base eventually separate from the diseased bone and a fragment breaks loose into the knee joint. It can then cause locking and sharp pain and leg weakness. If the fragments are loose, the surgeon may scrape the cavity to reach fresh bone and add a bone graft and fix the fragments in place. Fragments that cannot be mended are removed. This leaves a defect or a hole that needs repair.

Small defects can be treated with the micro-fracture technique, but larger ones require grafting. Grafts can be obtained through autograft (transplanting cartilage from one part of the knee to another), allograft (frozen grafts from a donor), cultured cartilage or newer, synthetic bone substitute that fills in over time with the patient's own cells.

For all of the repairs, the full healing process takes time. You may be asked to use crutches and a brace to protect the knee from impact load (often the original cause of the problem) which lets the body do the hard work of healing these defects. At first you may be in a knee immobilizer, a straight brace with Velcro straps. This allows you to protect that repair and still place a little weight on the leg for balance while using crutches. After the initial healing phase, 4-6 weeks, a knee hinge brace is often used to continue the protection of the healing cartilage for the first 3-4 months after surgery. A brace would be needed for heavier activities for up to one year after surgery in almost all cases. Sometimes in patients with heavier demands (bowed legs or a large defect), a special unloader brace will be used to allow for a return to activity while the graft incorporates and the new cartilage grows.

OCD Recovery Plan and Post-Operative Instructions

Diet:  You may resume a regular diet when you return home.  Most patients start with tea or broth adding crackers or toast, then a non-spicy sandwich.  If your stomach feels acidy, try Tums, Zantac or Pepcid AC to settle it and drink some clear liquids.

Lungs:  After surgery, you are encouraged to deep breathe and cough frequently (at least 3-4 times per day.)  This will reduce mucous  from building up in your lungs and will reduce the risk of developing a post anesthetic pneumonia.

Stop smoking: Smoking slows the healing process by interfering with the making of new DNA. Smoking also increases the risk of infection and pneumonia after surgery by slowing your body's white blood cells.

Pain Control:  Take pain medications as prescribed by Dr. Reznik.  Please call our office with any questions regarding your medications.  Ice as needed (never place ice directly on skin) and elevate leg above heart level using 2-3 pillows.  This will also decrease swelling.

Dressing: The dressing is to remain clean and dry. After 48 hours, you may remove all dressings. You may shower today.

Pat the incisions dry, don't rub the scabs off. Cover each incision with a plan Band-Aid. Do not use creams or ointments on the incisions.

Driving: Right knee patients and left knee patients with a standard transmission car cannot drive until off all pain meds and can fully weight bear without pain.

Crutches: You must use crutches for at least the first three weeks. After that, you will be fitted with a hinged knee brace in our office. Once in the knee hinged brace or custom unloader brace; you can advance to one crutch as comfort allows. Most patients are off crutches completely and in a protective brace by 6 weeks.

Return to Work:  People with light work (desk work with no squatting, lifting or kneeling) can return to work within a week.  Patients with active office work or very light labor with variable tasks can sometimes go back to work at two or three weeks, depending on lifting requirements.  Heavy work, (lifting or unprotected heights) cannot usually return before 6 weeks.  Most will need to be cleared by their physical therapist. The exception is for people who may have long commutes.  By staying still for too long after surgery or with the leg down for long periods, the blood flow slows and that increases your risk of a blood clot (DVT or Deep Vein Thrombosis).

Blood Clots:  Those at high risk of blood clots (DVT) include patients who have long car or train commutes, may be overweight (BMI >30)*, have a history of cancer, women on birth control pills or males over the age of 40. These patients should be taking an aspirin per day (unless allergic) for about 6 weeks depending on risk factors.  Doing the exercises Dr. Reznik prescribed will also reduce the risk of blood clots.

*BMI or body mass index is a number calculated from a person's weight and height. BMI provides a reliable indicator of body composition. The index is used to screen for weight categories that may lead to health problems: BMI

Airline Flights: Patients may fly 2-3 weeks after surgery on short flights (up to 2 hours) but in general wait 6-8 weeks for longer flights. You should get up and walk frequently to avoid blood clots and take aspirin unless allergic.

Dental Work: If you have any graft or implant in place, you cannot have any dental work (except for an emergency or to clear an infection) for at least three months following surgery. This includes all types of dental cleanings. The dental work can cause bacteria to get into the blood and infect the graft.

Any time that you have dental work, including any dental emergency, you will need an antibiotic for the first full year following your surgery.

Post-Operative Exercises

You will start doing exercises while still in the recovery room.

While resting in bed after surgery, do the following every hour:

	1.  Ankle Pumps: Pump your ankle up and down for 1 minute (like pressing on the gas pedal). This will increase circulation and reduce the risk of developing a blood clot. Do this with both legs. These help to decrease swelling and the risk of blood clots. You cannot overdo ankle pumps.
	2.  Straight Leg Raise:Tighten your quads (muscle in the front of your thigh) with the knee immobilizer on, and raise you leg 8 to 12 inches off the bed. Do three sets of 8-10 reps, alternating sides.

3. Deep breathing: be sure to regularly take a deep breath and blow it out. This helps to clear the lungs after an anesthetic. 

4. Stop smoking: smoking slows the healing process by interfering with the making of new DNA. Smoking also increases the risk of infection and pneumonia after surgery by slowing your body’s white cells.

5. If you find yourself in bed or resting frequently, move you arms when in bed. You can use very light weights for upper arm exercises when in bed to keep your muscles ready for the demands of using crutches.

6. Add other exercises as your therapist prescribes.

Revised 1/2/09