![Indications for revision TKR
Aseptic loosening of implants
[ most common cause 40-50 % ]
Patellar Complication [5-20%]
Polyethylene wear [10-15%]
Instability [8-12%]
Infection [6-10%]](https://image.slidesharecdn.com/implantselectioninrevisiontkr-170304193710/85/Implant-Selection-In-Revision-T-K-R-3-320.jpg)
Implant Selection In Revision T.K.R
- 1. IMPLANT SELECTION IN REVISION TKR DR. MURTUZA RASSIWALA, DNB RESIDENT, DEPARTMENT OF ORTHOPAEDICS AND TRAUMATOLOGY, UNIQUE SUPER SPECIALITY CENTRE, INDORE
- 2. INTRODUCTION Total knee replacement surgery is a successful operation for advanced arthritis of the knee. However ,the components can wear or loosen causing pain , swelling and instability, which may limit the joint mobility. Revision knee replacement surgery involves the removal of all worn or damaged knee components and replacement with new artificial components.
- 3. Indications for revision TKR Aseptic loosening of implants [ most common cause 40-50 % ] Patellar Complication [5-20%] Polyethylene wear [10-15%] Instability [8-12%] Infection [6-10%]
- 4. Challenges in revision TKR While in primary TKR, bone is the friend of the surgeon, and the defects are relatively small ; in revision TKR Bone itself is changed by 1.) infection, 2.)osteolysis due to polyethylene wear or 3.)mechanical damage due to loosening of a component.
- 5. Challenges in revision TKR Bone Defects :- Osteolysis is caused by polyethylene wear. The wear particles contribute to the bone defects called as “particle disease”. Most patients undergoing revision TKR are old & suffer from basic diseases like RA/OA and osteoporosis. Hence the bone stock is already compromised & quantitatively small.
- 6. Challenges in revision TKR Soft Tissue :- soft tissue may offer even more difficult problems a) What was the original incision & how was the soft tissue handling? b) What is the cause of instability – i. Over release ii. Under release
- 7. Challenges in revision TKR Alignment:- If ligaments are present, they must be correctly tensioned and balanced by choosing the correct prosthesis size and correctly positioning it. In many cases, constraint WILL NOT be necessary If the ligaments have failed, a constrained implant still needs perfect alignment.
- 8. General principles for revision TKR Clarify the cause of failure. Use adequate surgical exposure Restore limb alignment Achieve soft tissue balance Use correct implant Restore the joint line Obtain a good Range of motion
- 9. JOINT LINE Definition: The joint line is the articulating surface of the femoral component in extension, flexion and all points in between. Anatomical Landmarks: One finger above the fibula head One finger below the inferior patella pole 30 mm distal to the medial femoral epicondyle 12-16 mm distal to the femoral attachment of the PCL Old meniscus scar Re-establishing the correct joint line is paramount in achieving good functional outcome in revision knee replacement
- 10. .
- 11. CLASSIFICATION OF SOFT TISSUE DEFECTS :- 1. LCL ABSENT • Align the knee • Brace for 3 months post op to restore lateral stability • Posterior stabilized implant
- 12. CLASSIFICATION OF SOFT TISSUE DEFECTS :- 2. PCL ABSENT • Assure flexion/extension space balanced • Posterior stabilized implant
- 13. CLASSIFICATION OF SOFT TISSUE DEFECTS :- 3. MCL ABSENT • Reconstruct MCL and brace post op • Rotating Hinge Implant
- 14. CLASSIFICATION OF SOFT TISSUE DEFECTS :- 4. MCL and LCL ABSENT • Rotating Hinge Implant
- 15. Bone Defect Zones for Revision TKR
- 16. Metaphyseal Sleeves Based on the principal of zonal fixation: 1. If the zone 1 is sufficient, bone quality is overall good, alignment and ligament balance reconstructed, a stemless fixation can be an option. 2. Sleeves should be used with stems if the zone 1 is compromised. 3. In case, a tibial stem is used, the diameter should be 14mm or less, in order to make removal easier.
- 17. Metaphyseal Sleeves Fixation in zone 2. Made of Titanium with sintered beads of 50 to 80 % porosity on surface . Morse taper fixation so no cement required . Axial as well as Rotationally stable. Wolf’s law induces bone growth on the surface Indications for Metaphyseal Sleeves New level of immediate fixation Management of severe bone loss Stability of construct controlling flexion gap and the joint line Uncemented fixation
- 18. Problems Radiolucent lines (needs followup ….). Intraoperative fracture. How “In the god’s name will you remove a well fixed sleeve .”
- 19. Till now largest series and longest follow up • 121 pts • 196 sleeves • 3.6 years follow up . • Good outcome .
- 20. Tantalum cone Tantalum as a metal has high volumetric porosity (70–80%) low modulus of elasticity (3 MPa) high friction characteristics Hence uniform load distribution . No stress shielding. Also has less bacterial adherence
- 21. Sleeves v/s cones Fixation and Augmentation Both Augmentation only
- 22. Tibial stems Designed for intramedullary load sharing and press-fit with excellent stability •Bypass cortical defects Fluted Tibial Rods •Lengths 75, 115, and 150mm •Cemented Stems •Lengths 30 and 60mm standard •Tapered 90, 120, 150mm •Diameter -13mm Only
- 23. Role of tibial stem Support for implants Fixation stability Distribution of shear stress Reduction in bone cement stress When defect is more than 5mm after the tibial cut .
- 24. Femoral augments Handed distal femoral augments •4mm •8mm •12mm •16mm Posterior femoral augments •4mm •8mm
- 25. Tibial Step Wedges Sizes 1-6 •Thicknesses 5, 10, and 15mm •May be downsized relative to tray •Universal –for use on medial, lateral, or both sides Note: If you use a tibial wedge you can NOT use a tibial sleeve
- 26. Wedge v/s block Block augmentation better than wedge in strain distribution, tensile deformation rate, compression deformation rate, and shear deformation rate. Wedge better than block in removal of less bone .
- 27. The chart below shows the recommended implant systems using the Engh Bone Defect Classification System and ligament stability in the patient’s joint.
- 29. Types of implants Unconstrained Semi constrained fully constrained
- 30. Fully Constrained Implants Here the tibial and femoral components are linked to each other,like in a hinge. advantage- stable implant,does not require much bony and ligamentous support. Use- tumour and revision tkr surgery Disadvantage- supra physiological forces produced causes implant and bone wear Eg- Walldius, Shiers, Guépar, Kinematic rotating hinge.
- 31. Fully Constrained Implants Constraint should only be used in revision TKR after the principles of extension , flexion gap and medial and lateral collateral ligament balancing are performed As little constraint as possible should be used If stability cannot be obtained , only then , progressive levels of constraint should be tested and used in the construct.
- 32. Un Constrained Implants Opposite of fully constrained implants Not mechanically limited in their movements, but rely on conforming joint surfaces and soft tissue guidance. Very low constraint forces during entire joint motion arc. Eg- Modular type-Marmor, Lotus, Savastano polycentric type (for unicompartmental knee arthroplasty)
- 33. Semi constrained implants Semi-constrained implants have near physiologic constraint and are divided into - posterior cruciate ligament-preserving, posterior cruciate ligament sacrificing Many prostheses fall into this category, including the geomedic, anametric, total condylar, kinematic, Kodama-Yamamoto, ceramic devices and others.
- 34. Clinical cases and discussion
- 35. CASE 1 : Instability Pre revision AP and lateral x rays showing assymetric polyethylene wear and major proximal tibial and femoral lysis. History A 68 year old female presents 6 years after left TKR. Investigations •All blood parameters are normal. • Joint aspiration negative. •Plain X-rays reveal significant osteolysis of lateral tibial plateau and femoral metaphysis. •Asymmetric bearing wear is noted suggestive of polyethylene bone granuloma. •The stabilised ‘plus’ bearing is indicative of poor balance at the initial primary TKR.
- 36. Problem Excessive constraint, in an unbalanced knee, leading to early polyethylene wear and bone lysis. At explantation bone loss will inevitably be greater than pre-operative films indicate once the granuloma have been removed to healthy bone. What would you do? Simple bearing exchange or full revision? How would you achieve fixation? How would you reconstruct the bone defects? How much constraint will be needed at revision?
- 37. SOLUTION A full revision is required to reconstruct bone defects and achieve secure fixation. We used 2 zone fixation (metaphyseal sleeve in zone 2 and stems in zone 3). The sleeves also provide secure reconstruction and load the metaphysis to regenerate bone stock (Wolff’s Law). By re-establishing the joint line in extension and flexion, the ligaments can be balanced and reduced constraint is needed (from stabilised plus to PS).
- 38. CASE 2 : Bone Loss Pre operative AP and LATERAL X-Rays showing significant osteolysis and bone loss History Male age 85 had a successful left TKR 10 years earlier, presents with increasing discomfort and swelling. Investigations Examination reveals collateral pseudo-laxity secondary to loosening and subsidence of the tibial and femoral components. X-rays confirm significant tibial and femoral lysis. All blood parameters are normal and joint aspirate was negative.
- 39. Problem Significant bone loss secondary to polyethylene wear. Revision TKR will need to address problems of bone reconstruction, implant fixation and ligamentous balance. What would you do? Revise to cemented stems and a rotating hinge implant? Reconstruct with metal / bone graft block augments and diaphyseal engaging stems? Use metaphyseal sleeves to achieve bone reconstruction and implant fixation? Use porous metal reconstruction cones to overcome bone loss and use cemented fixation? Arthrodesis?
- 40. SOLUTION Post revision AP and LATERAL X-Rays showing metaphyseal sleeve tibial reconstruction In this case both reconstruction and implant fixation were achieved using metaphyseal sleeves supported by uncemented stems. Bone reconstruction allowed the joint line to be re-established such that ligament balance allowed a posterior stabilised mobile bearing.
- 41. Why not the other options? Porous cones and cemented stems would also be an acceptable but more complicated option. Metal / bone graft block augments and diaphyseal stems provide a less reliable reconstruction and fixation compared to other methods. A cemented stem, rotating hinge would achieve a satisfactory outcome but is unnecessary, as is arthrodesis.
- 42. CASE 3: Peri- Prosthetic Fracture AP and LATERAL X-Rays at presentation showing displaced,non united supracondylar femur fracture History Female age 84, fell at home and sustained a supracondylar fracture above a well functioning TKR. Initial management was conservative but after 8 weeks the position was deemed unacceptable, the fracture un- united and the patient referred for further management. Investigations Examination confirmed a painful non-united distal femoral fracture. X-rays revealed a displaced, mal-rotated fracture. All blood parameters were normal.
- 43. Problem Displaced type 2 femoral supracondylar peri- prosthetic fracture with delayed presentation. What would you do? Continue non-operative management and anticipate bone union, then mobilise? Open reduction and internal fixation? Revision knee replacement to reconstruct and bypass the fracture? Distal femoral replacement?
- 44. SOLUTION Post revision AP and LATERAL X-Rays at 12 month review showing restored femoral alignment and fracture union In view of the patients age, unacceptable position and non-united fracture, revision to a rotating hinge using metaphyseal sleeves to reconstruct and provide satisfactory fixation was performed. Immediate full weight bearing post-revision was possible.
- 45. Take home message Diagnosis-must be sure “REVISE” – do not repeat Use revision implants Complete revision Build the knee from the tibia Femur controls the tissue tension and joint line Rotating hinge for gross instability and bone loss
- 46. THANK YOU