ocd. of knee in traumatic conditions ppt

osteochondral defects of knee

1. OSTEOCHONDRAL DEFECTS IN KNEE BY DR RAMGOPAL MODERATOR DR VAMSI DOS 6/5/22 DOA 8/5/22

2. INTRODUCTION Articular cartilage is an avascular and aneural tissue composed of chondrocytes and extracellular matrix. Articular cartilage is a complex tissue that is able to withstand tremendous force . But does not have the ability to heal even after a minor injury. Health and function of a joint depends on the viability of articular cartilage. In young individuals articular cartilage is damaged by trauma whereas in older individuals they are degenerative changes.

3. In adults articular cartilage doesn’t have neither a blood supply nor lymphatic drainage. Sheltered from immunologic recognition by surrounding extracellular matrix. These defects usually enlarge with time . Play a role in the development of arthritis.

4. Trauma to the articular cartilage causes reduction in viscoelasticity and stiffness of cartilage. The increased stiffness of sub chondral bone allows more stress to be transmitted t the cartilage. A vicious cycle of cartilage degeneration and stiffening occurs. Initially they are small and asymptomatic . Later they increase in size and become painful.

5. CLINICAL PRESENTATION Most common presentation is a loose body. It may be associated with an acute injury with large effusion Or insidious onset with no effusion Some patients may have joint line pain and symptoms of locking The physical examination does not elicit a consistent finding other than localised pain with or without effusion.

6. Patients with articular cartilage injury usually complain of Pain Effusion Mechanical symptoms.

7. Evaluation of a patient suspected of having having a osteochondral lesion of knee should include Weight bearing AP Patellar view Clinical suspicion of articular cartilage injury should prompt evaluation with MRI

8. NON OPERATIVE TREATMENT The goal of non operative treatment is to reduce symptoms related to articular cartilage. Pharmacological therapy includes mild analgesics , local corticosteroid injections Chondroprotective agents like oral glucosamine , chondroitin sulfate , and injectable hyaluronic acid. Patient education ,activity modification , muscle strengthening

9. OPERATIVE TREATMENT Most widely used techniques are arthroscopic debridement , lavage and repair stimulation.

10. Microfracture and arthroscopic lavage and debridement : It can improve symptoms. But there is no potential for healing Attempts to enhance healing potential of articular cartilage have been focussed on recruiting pleuripotent cells from bone marrow.

11. The usual result of this technique is partial filling of articular cartilage with fibrocartilage. It contains predominantly type 1 collagen. Fibrocartilage has diminished resilience , stiffness, poor wear and tear , and deteriorates with time.

12. The first line palliative treatment method is arthroscopic debridement and lavage. Debridement includes smoothing of articular surfaces, removal of inflamed surfaces , . Lavage of the joint clears fragments of cartilage and calcium phosphate crystals. In microfracture , controlled perforation of subchondral plate is done. So that there is efflux of pleuripotent stem cells and growth factors in the lesion.

13. OSTEOCHONDRAL AUTOGRAFT TRANSFER SYSTEM A larger bone defect which involves subchondral bone requires autologous bone transplantation. Indications include Symptomatic unipolar lesions Age < 50 Lesion size < 2cm

14. It is usually done using arthroscopy or arthrotomy. Grafts are obtained using harvestors . Harvestor is placed perpendicular to the donor site and advanced into the subchondral bone to a depth of 12-15mm Recipient socket is formed , and donor graft is placed into it.

15. AUTOLOGOUS CHONDROCYTE IMPLANTATION Here mature articular chondrocytes are harvested , expanded in cell culture , implanted into the defect. Subchondral bone plate is preserved. Indicated in young patients with defect greater than 2-4cms.

16. Autologous chondrocyte implantation is an established technique used to treat osteochondral lesions in knee. ACI is successfully used to treat isolated chondral lesions of knee. For larger defects we have combined the use of ACI with subchondral bone grafting.

17. OPERATIVE TECHNIQUE : Firstly all the patients are assessed pre operatively to characterise the chondral deficiency. Arthroscopically the lesion is assessed . From a non weight bearing surface full thickness cartilage is being harvested. Placed in transport medium and chondrocytes are cultured.

18. Second stage surgery is done after 4 weeks using a midline incision and arthrotomy . The defect is debrided back to a healthy rim of cartilage Residual cartilage and sclerotic bone is usually removed. Cancellous bone graft is harvested from medial femoral condyle and impacted into the defect. Then MACI membrane is implanted into the base of defect using fibrin glue

19. Second membrane is placed with its cells facing those of first. Gentle pressure is applied onto the graft. Knee is put through range of motion to assess the stability of graft. The leg is placed in robert jones dressing and POP slab applied. Full weight bearing is allowed only after 24 hours and isometric exercises are recommended.

20. OSTEOCHONDRAL ALLOGRAFT Used for larger full thickness lesions. Fresh allografts provide greatest likelihood of chondrocyte survivability But also carry high risk of immunologic and transmissible disease. Use of shell graft with less than 1cm subchondral bone reduces immunogenicity.

21. Technically it has got more constraints Fresh tissue from a young donor must be available . All graft host reactions limit this technique usage.

22. INDICATIONS : Young active patients with large focal defect Failure of previous cartilage repair Osteonecrosis Post traumatic osteochondral defects.

23. SURGICAL TECHNIQUE : Patient in supine position , knee in 30 degree flexion . Diagnostic arthroscopy is done to identify the lesion . Arthroscopic debridement is done to the chondral lesion back to stable margin. Once the defect is visualised , it is measured. a guide wire is introduced into the centre of lesion .

24. Then appropriate reamer is advanced over the guidewire . Affected area is reamed until healthy bleed appears. Small holes are drilled into the recipient site with a drill. Then graft is obtained and advanced into the recipient site with gentle pressure. The grafts may not facilitate a press fit and require fixation with screws. Wound is closed in layers.

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