ALTERNATIVE BEARING SURFACE Wear Rate - ICJR

1、Decision Making in the Active Patient with Hip Arthritis,David G. Lewallen, MD Professor of Orthopedics Mayo Clinic Rochester, MN,47 yo,Disclosure : David G. Lewallen MD,Royalties : Zimmer Consultant : Osteotech, Orthosonics, Zimmer Institutional Research Support : Dupuy, Smith De Smet et al; Campbe

2、ll,43 Degrees,Metal on Metal THA :The Really Ugly,Metal Sensitivity Joint Effusion Pseudotumors ALVAL,“Adverse Metal Response” “Adverse Local Tissue Response”,60 y/o female with hip pain,Preop Postop 1 Year,1 Year Post Revision to Another MOM,Persistent groin pain, dislocation,10/17/2008,10/17/2008,

3、10/17/2008,10/17/2008,Early Pain Relief and Return of Function,ALVAL Aseptic Lymphocytic Vasculitis Associated Lesions,Davies AP, Willert HG et al. JBJS Am. 2005,Mayo Clinic Series : Failed MOM Arthroplasties,37 Revision Cases over 3 Years (3.5% of all revision cases) 6/37 (16%) had Index Arthroplas

4、ty at our Institution 24/37 Female (65%) 3/37 Resurfacing Implants, the rest Standard THA 29 were post MOM primary Arthroplasty 10/37 : “adverse reaction” to Metal on Metal Implant 7 of these 10 Female (70%) 7 Implant types from 5 companies: Biomet M2a, Depuy ASR, Depuy Ultamet, Stryker Optimom, Str

5、yker Cormet, Wright Medical Conserve, Zimmer Durom Browne, et al : CORR 468(9):2313-20, 2010,Mayo Clinic Series : Failed MOM Arthroplasties “Adverse Local Tissue Reaction”,Clinical Presentation: Pain and sx since index arthroplasty Typically groin pain, and pain with active flexion Clunking or poppi

6、ng 4/10 Audible Squeaking in 1 2/10 large fluid filled pseudo tumors,Mayo Clinic Series : MOM THA Revisions,Meta on Metal THA :Potential Failure Modes,Infection Osteolysis Loosening Instability Femoral Neck Fracture (Surface Replacements only) Systemic Metal Ion Level Elevation Metal Hypersensitivit

7、y Effusions, Pseudotumors, ALVAL,Meta on Metal THA :Potential Failure Modes,Infection Osteolysis Loosening Instability Femoral Neck Fracture (Surface Replacements only) Systemic Metal Ion Level Elevation Metal Hypersensitivity Effusions, Pseudotumors, ALVAL,Why? How often ? Long Term Effects ?,When

8、(not if) You See a Painful Metal on Metal THA : Recommended Workup,History (skin rashes with jewelry, wound healing problems, neurologic sx, general hx) Exam (irritable hip, swelling or mass, local rash) Labs: WBC, CRP, ESR Hip Xrays Other imaging : CT, MRI, Ultrasound Hip Aspiration for cell count

9、and culture High Index of Suspicion (beware occult loosening of monoblock Co-Cr cups),Accepted Indications (For Some) for Metal on Metal,Young active patient wants to continue to be active Most commonly male Females who are not in child bearing age No renal problems or comorbidities that have a high

10、 risk of developing renal problems No known hypersensitivity to metal,ALTERNATIVE BEARING SURFACEOther Options?,Metal-on-metal Ceramic-on-metal (not FDA approved) Ceramic-on-ceramic Highly cross-linked polyethylene,SQUEAKING IN CERAMIC-CERAMIC THAIntroduction,Developed by Pierre Boutin* in the 70s,B

11、outin, Rev Chir Orthop Reparatrice Appar Mot, 1972;58(3):229-246 Boutin, CORR 2000;379:3-11,ALTERNATIVE BEARING SURFACECeramic-on-Ceramic,Advantages: Very low wear rate under most conditions Limited but favorable track record,ALTERNATIVE BEARING SURFACECeramic-on-Ceramic,Disadvantages: Fracture risk

12、 (now decreased) Risk of runaway wear with malposition and edge loading Impingement risk Modular ceramic-metal junction problems Squeaking,ALTERNATIVE BEARING SURFACECeramic-on-Ceramic,Fracture Risk: Decreased with modern technology Ceramic: smaller grain size, increased burst strength “Proof testin

13、g” of each implant Estimated 1974 risk 1 in 300 Estimated current risk 1 in 2,000-10,000,ALTERNATIVE BEARING SURFACECeramic-on-Ceramic,Sensitive to Cup Position: Too vertical: edge loading, runaway wear Improper version: impingement of metal-ceramic or metal-metal,ALTERNATIVE BEARING SURFACECeramic-

14、on-Ceramic,Results: Long-term european results (Sedel) favorable with low wear, little lysis,Courtesy of HSS,Bar Linkage,Motor,Rotating jig,Rotating table,Box,Servo-Hydraulic Testing machine,LOAD,SQUEAKING IN CERAMIC-CERAMIC THAMaterials and Methods,SQUEAKING IN CERAMIC-CERAMIC THAResults,Dry Condit

15、ion: Normal gait, normal loading Stripe wear Stripe wear & extreme load Edge wear & extreme load Metal transfer Microfracture,All squeak quickly & remained constant,SQUEAKING IN CERAMIC-CERAMIC THAResults,Lubricated Condition: Normal gait, normal loading Stripe wear Stripe wear & extreme load Edge w

16、ear & extreme load Microfracture,No squeak up to 11,000 cycles,SQUEAKING IN CERAMIC-CERAMIC THAConclusion,Squeaking noise is a problem of COC lubrication Noise occurs when the film fluid between the two surfaces is disrupted, we feel most commonly secondary to metal transfer,SQUEAKING IN CERAMIC-CER

17、AMIC THAConclusion,Metal transfer as primary mode leading to fluid lubrication disruption may explain why squeaking is more common in certain designs,SQUEAKING IN CERAMIC-CERAMIC THADiscussion,Squeaking commonly reported with certain designs - in this design metal transfer can easily occur,Restrepo

18、JOA 2008,HIGHLY CROSS-LINKED POLYETHYLENE,CROSS-LINKED PECross-Linked PE,Pros: Less radical departure from something we know works pretty well versus hard-on-hard,CROSS-LINKED PECross-Linked PE,Cons: Some encouraging clinical data (now to 10 years) But : weve heard about “improved PE” before,CROSS-L

19、INKED PEWear Data,Dramatically better wear than conventional PE on wear simulators,CROSS-LINKED PEWear,Why believe wear simulator data, when they have been wrong before?,CROSS-LINKED PEWear,Better understanding of PE wear mechanisms Better wear simulators More aggressive/realistic tests - scratched

20、femoral heads - 3rd body abrasives,CROSS-LINKED PEMaterials Properties,Cross-linking leads to changes in other materials properties besides wear resistance - lower yield strength - lower ultimate tensile strength - lower elongation to failure - lower impact strength - lower resistance to crack propa

21、gation Most of these changes are small-moderate decrements,CROSS-LINKED PEMaterials Properties,Materials Properties: Potential Problems: Risk of liner fracture Risk of locking mechanism failure Especially if malpositioned !,broken standard PE embrittled by oxidation,CROSS-LINKED PEMaterials Properti

22、es,Manufacturer Dependent: Degree of cross-linking Method of free radical formation Method by which free radicals extinguished Post cross-linking treatment,CROSS-LINKED PEWear Particles,Dramatically lower wear rate should lead to less osteolysis This hope would not be realized if particulate debris

23、from cross-linked PE (by virtue of size or shape) was more potent biologically than conventional PE debris,ALTERNATIVE BEARING SURFACEConclusions,Improved bearing surfaces may revolutionize total joint replacement Now that implant fixation is so good it is reasonable to ask: Can alternative bearings provide a long-term solution for you