Long-Term Results of Partial Surface Replacement for Osteonecrosis: A Minimally Invasive Approach
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This study evaluates the outcomes of partial surface replacement surgery in young osteonecrosis patients, discussing surgical techniques, implant design, and rehabilitation. Key findings reveal that the MMS implant preserves hip anatomy with a minimally invasive approach. Despite some limitations, the procedure shows promise with a survival curve indicating a significant percentage of implants remaining functional after up to 14 years. The results underscore the need for careful patient selection and consideration of preoperative conditions to optimize outcomes.
Long-Term Results of Partial Surface Replacement for Osteonecrosis: A Minimally Invasive Approach
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Presentation Transcript
Partial Surface Replacement5 to 14 Years Results T. JUDET T.SIGUIER J-L.MARMORAT P.PIRIOU B.BRUMPT M.SIGUIER Raymond Poincaré Jouvenet IMK 2006
Osteonecrosis mainly affects young patients: How to avoid THR? • Core decompression • Cancellous bone grafting • Vascularized bone grafting • Intertrochanteric osteotomies • Rotationnal basi-cervical ostéotomies
Drawbacks, limits and failures of conservative surgery • Technically over-demanding procedure • Long lasting rehabilitation • Unpredictable results • Controversial efficiency • Major anatomical disturbance of the upper femur
Partial resurfacing conceptMarc Siguier 1990 • Minimalist design and operative technic • Replacement anatomically limited to the pathologic area • Preservation of the hip anatomy • Preservation of the mecanical properties of the femoral neck
The MMS Implant • 120° Covering area • Range 40 to 60 mm diameter to match the exact sphericity (2mm increment) • Dedicated instrumentation for each size • Cemented fixation
Surgical technic • Anterior approach on fracture table • T-shaped capsulotomy • Anterior dislocation preserving circumflex vessels • Excision of the ostéochondral collapse and under-lying loose necrotic bone
Surgical technic • Measurement of the femoral head • Preparation of the prosthesis setting in line with the center of the head
Surgical technic • Trial implantation without tilting and flush or beneath the surface of the healthy remaining cartilage • Cementation of the definitive prosthesis
Post operative care Immediate rehabilitation and full weight-bearing
Interrogations and potential problems • Quality of bone-implant fixation • Evolutivity of the pre-OP necrotic area • Post-OP extension of the necrotic area toward the pre OP limits • Cartilage tolerance to the implant and further degenerative changes
Previous published results • Siguier M , Judet T, Siguier T & al J.Arthroplasty 1999 Preliminary results of partial surface replacement of the femoral head in osteonecrosis 25 procedures 6 failures (FU 20-60 mths) • Siguier T, Siguier M, Judet T & al Clin. Orthop. 2001 Partial resurfacing arthroplasty of the femoral head in avascular necrosis Methode, indication and results 37 procedures 9 failures (FU 24-89 mths)
Actual Serie • Continuous Serie April 1991 - Jan 2001 • 61 MMS procedures (54 patients) • Age 42 years (24 - 59) • 45 Males et 9 females • Aetiologies Post trauma 6 cases Steroïds 11 Cases (9 patients) Alcool/tobacco 7 cases (5 patients) Idiopathic 35 cases (32 patients)
Clinical Pre- operative Status • Postel Merle-d’Aubigné score 12 pts (8 - 17) Pain 2,3 pts (1 - 4) No preventive surgery
Radiological Pre-operative status • Ficat & Arlet Staging • Stade II : 1 case • Stade III : 41 cases (67 %) • Stade IV : 19 cases (31 %)
Radiological Pre-operative status • Evaluation of the necrotic area size after M.Kerboul -Angular measurement on AP view and Lequesne false profile view Mean angle AP : 121° (70 to 180) Mean angle Profile : 116° (50 to 180)
Radiological Pre-operative status • Evaluation of the necrotic area size -Max depth of the necrotic area; 4 zones to define superficial or deep involvement Stage 2 : 28 % Stage 3 : 53 % Stage 4 : 19 %
Results : 56 over 61 implants1 deceased (2 hips) and2 patients (3 hips) lost to FU before 5 Yrs • Implant removal : 31 cases • Implant still in place : 25 cases
Results : Implant removal : 31 cases • early technical failure • extension of the necrotic zone - head collapse
Results : Implant removal : 31 cases • sinking of the implant • joint line narrowing and degenerative changes No difference statistically significant : failure vs Ficat staging Difference statistically significant : failure vs depth (p < 0,01)
Survival curve • End point : implant removal
Second look surgery • THR through the same mini invasive anterior approach • Resurfacing arthroplasty • No difficulty related to the previous surgery
Conclusion • Optimistic : for 25 patients 40 yrs old, improvement lasting 8 years (5 - 14,5) with a pain scoring rising from 2,3 to 5,1. No deleterious effect on secondary procedure • Realistic : survey curve 50 % à 10 years 46,5 % à 14 years
Conclusion • Prospective in the up to date context of mini-invasive surgery, mini-implants are highly attractive and our long term experience of partial hemi resurfacing of the femoral head must render any surgeon very prudent concerning analogous procedures.