Revision Total Knee Arthroplasty

1. Revision Total Knee Arthroplasty Amjad Moiffak Moreden, M.D. Department of Orthopaedic Surgery The General Assembly of Damascus Hospital Ministry of Health Damascus, Syria Mar. 18, 2008

2. ASEPTIC FAILURE OF PRIMARY TOTAL KNEE ARTHROPLASTY Between 4.3% and 8.0% revision rate was seen at 7 years after primary TKA caused by several factors : • Component loosening. Tibial>Femoral • Polyethylene wear with osteolysis • Ligamentous laxity • Periprosthetic fracture • Arthrofibrosis • Patellofemoral complications

3. Cont… • Malalignment of the limb • Patients with high activity demands • Excessive component constraint • Duration of implantation

7. Complete radiolucent line of 2 mm or more around the prosthesis at the bone-cement interface in cemented arthroplasty • Incomplete radiolucencies of less than 2 mm are common and have not been shown to correlate with poor clinical outcomes in cemented TKA

8. Fluoroscopic examination may be helpful in patients with unexplained pain after TKA and normal roentgenograms • Stress roentgenograms to document less severe instabilities • Routine knee aspiration revealed a preponderance of RBCs, averaging 64,000/mm3

9. Instability is an increasingly frequent cause of TKA failure that requires revision • 20% of TKA revisions performed over 8 years were done because of instability

10. Causes of instability • Ligamentous imbalance and incompetence • Malalignment and late ligamentous incompetence • Deficient extensor mechanism • Inadequate prosthetic design • Surgical error

11. The Insert • Polyethylene wear can cause failure of TKA either by contributing to loosening and osteolysis or more rarely by catastrophic failure through polyethylene fracture • Rarely, worn modular polyethylene inserts may be exchanged as an isolated procedure, provided the remaining components are well-fixed and well-aligned

12. Implant systems with variable levels of constraint are extremely helpful in the revision setting but must be combined with careful attention to implant alignment, ligamentous balancing in both flexion and extension, joint line restoration, and patellar tracking.

14. REVISION EXPOSURES • Should use the previous TKA skin incision if possible • When two previous incisions already exist, the more lateral of the two should be selected • A standard medial parapatellar arthrotomy

16. The quadriceps turndown procedure

17. Modification of the quadriceps turndown procedure “rectus snip”

18. Tibial tubercle osteotomy procedure

20. Restoring the Synovial Recesses over the Femoral Condyles

22. Procedures’ outcomes • V-Y quadricepsplasty resulted in greater extensor lag but increased patient satisfaction compared with tibial tubercle osteotomy • Both the quadricepsplasty and osteotomy groups had significantly lower outcome ratings compared with the standard arthrotomy and rectus snip

23. COMPONENT REMOVAL • The prosthesis-bone interface should be examined on both the tibial and femoral components • Remove the femoral component first because this allows better clearance for the tibial component

26. COMPONENT REMOVAL Cont. • The tibial component is removed in a similar fashion • The patellar component should be removed if there is evidence of patellar component wear

31. RECONSTRUCTION PRINCIPLES • The joint line should be reconstructed as close as possible to its anatomical position • Bone defects must be treated appropriately • Appropriate limb alignment must be ensured • Revision components should have a comprehensive variety of metal augmentations, stem extensions, and constraints

32. RECONSTRUCTION PRINCIPLES Cont. • Debridement of hypertrophic synovium • Thinning of scarred capsular tissue, the suprapatellar pouch, medial and lateral gutters, and posterior femoral recesses • PCL usually is scarred or incompetent, therefore use PCL-substituting prostheses for revision arthroplasty • When there is gross incompetence of the MCL or the combined lateral supporting structures, the decision to use a constrained condylar type of prosthesis

34. The Tibial Prep. • Defects of less than 5 mm can be filled with cement. Larger contained defects are filled with cancellous graft. Modular wedges and blocks or structural bone grafts could be used. • Patients with extremely poor bone quality may require a cemented stem if adequate press-fit cannot be achieved.

35. The Tibial Prep. Cont. • The level of the joint line roughly one fingerbreadth above the proximal tip of the fibula and one fingerbreadth distal to the inferior pole of the patella

38. The Tibial Prep. Cont. • Rarely, a custom tibial component or a proximal tibial allograft may be necessary because of extensive bone loss

39. Pre and Post op.

42. The Femoral Prep. • Augmentation of the femoral condyles distally or posteriorly or both is needed to balance the flexion and extension gaps without significant joint line elevation. • Use a larger femoral component in the anteroposterior dimension, with distal and posterior metal augmentation

43. The Femoral Prep. Cont. • Rotation of the femoral component should be determined using the epicondylar axis

45. The Femoral Prep. • Bone defects on the femur generally are managed with metal augmentation • Small defects and larger defects can be filled with cement

46. Patellofemoral joint • Retention is possible only when a securely fixed component shows minimal wear • Replacement is possible when the residual bone stock allows preparation of an adequate bony bed with fixation holes and the possibility for cement intrusion • Excision for the inadequate bone stock

47. RESULTS OF REVISION KNEE ARTHROPLASTY • The clinical results of revision TKA are not as good as the results of primary arthroplasty • Series with at least 5 years follow-up reported good to excellent results in 46% to 74% of patients. • 22% (6 of 27) reoperation rate at 9.8 years postoperatively

48. RESULTS OF REVISION KNEE ARTHROPLASTY Cont. • Deep infection rate 4.5% in revision arthroplasties followed for 5 years, repeat revision follow-up of 7.5 years, reported a 20% infection rate , are significantly more frequent than after primary TKA which is 1.6% to 2.5% • Complications of the extensor mechanism reoperation was necessary in 41% • Aseptic loosening, wound problems, and tibiofemoral instability

50. THE END