Sh Short ort St Stems ar are t the An Answer i r in 2017 2017 – Wa Wake-up Stefan Kreuzer, MD/MS Houston, Texas
Discl closure/Affiliati tions: Device companies Board Member/Advisory Board • Corin: Consulting/speaking, Research support, Royalties • ISTA • Smith and Nephew: Consulting/speaking, Research • ICJR support, Royalties (in the past) • MBJ-RF • Stryker: Royalties • Surgical Care Affiliates: Medical Advisory Board • Zimmer/Biomet: Consulting, Royalties • Employers Direct: Medical Advisory Board • Medtronic: Consulting/speaking Investments/ownership: • Depuy: Research support through MBJ-RF • IOT • Pacira: Consulting/Speaking • K and S solutions • Brain Lab: Consulting/speaking • Alpoza • Intelli-Joint Surgical: Consulting/speaking • Orthosensor • Think Surgical: Consulting, Research • Argentum Medical (silverlone) • Knee 360: Consulting (none-compensates) • Inov8 Surgical • Shukla: Consulting • Invo8 Healthcare • Swift Path: Consulting/speaking • First Street Surgical Hospital • Pulse: Consulting/speaking, Royalties • Texo-Venture • Your Practice on line: Consulting (none compensated) • Employers Direct
Why a a Nec eck P Pres eser erving I Implant? t? • Better clinical outcome • Reduced dislocation rate • Better ability to reconstruct Hip Center
Ne Neck ck-Pr Pres eser erving S Sho hort-Stem Implant nt vs. s. Conv nvent ntiona nal Neck-Sac Sacrif ific icin ing I Impl plan ant Femoral neck preservation and loading Positive clinical outcomes/Excellent long term success • Proper offset and leg length can be achieved easily • • No proximal loading is achieved • Bone preservation is sub-optimal • Curved structure designed to match shape of the femoral neck. • More loading in femoral neck and intertrochanteric area of the proximal femur. • Significant reduction in both torsional and bending moments at the stem/bone interface. • Decrease of micromotion and associated failure of osseointegration
Ne Neck ck-Pr Pres eser erving S Sho hort-Stem Implant nt vs. s. Conv nvent ntiona nal Neck-Sac Sacrif ific icin ing I Impl plan ant Femoral neck preservation and loading Intact Conventional MiniHip femur
Neck Ne ck-Pr Pres eser erving S Sho hort-Stem Implant nt vs. s. Conv nvent ntiona nal Neck-Sac Sacrif ific icin ing I Impl plan ant Methods • IRB approved data registry • Retrospective analysis of Hip disability and Osteoarthritis Outcome Score (HOOS) • Follow-up period of three years, patients age and BMI matched 90 patients with received neck-sacrificing implants (Accolade II: Stryker, Kalamazoo, • Michigan, USA) • 105 patients received neck-preserving short-stem implants (MiniHip: Corin Group PLC, Cirencester, UK) • Multivariate analysis of HOOS subscores (follow-up period employed as covariate) and non-parametric testing of post operative scores
STROBE flow chart of participants and study size. Date range for cases included in initial data set was January 2004 – October 2014; MiniHip cases started from September 2010
Surgery Neck-Sacrificing MiniHip A 42 53 Charnley Classification B 5 3 C 43 49 I 12 8 ASA Classification II 50 67 III 28 30
Pr Preope perative Pos ostop operative * * * * * *= p<0.05 100 100 MiniHip MiniHip Neck-Sacrificing Neck-Sacrificing 50 50 0 0 Symptoms Pain ADL Sports QOL Symptoms Pain ADL Sports QOL • Multivariate analysis showed significant effect of time, time x gender, time (pre- versus post- surgery) and surgery type • Follow-up tests showed significant postoperative differences between HOOS subscores for different implant types
What do these 3 x-rays have in common??
Facts cts on Dislocati tion: HSS • The frequency of dislocation was 2.1% (147 of 7040 patients).
Femora ral Anteve version • Low anteversion • High anteversion
Range of Femoral version was -19 to +33 degrees and only 8% were within the normal range of 10 to 15 degrees. Sendtner et al Acta Orthopedica, 2010; 81 page 579
Disloc ocatio ion r rate o of 1150 c con onsecutiv ive Neck eck P Preser ervin ving H Hip R Replacem cemen ents ts? 0%
Virtual Implantation Study October 2013
Results The following table shows the average deviation of the implanted femoral head centre from the natural femoral head centre, in each of the 3 planes (x, y and z), when implanted with either a MiniHip or a Metafix stem Average MiniHip (mm) Metafix (mm) deviation X 1.71 4.43 Y 0.87 3.19 Z 1.81 3.44
Results Table: The anteversion deviation for each femur when implanted with either a MiniHip or a Metafix stem. Femur Version (°) Anteversion deviation with MiniHip™ Anteversion deviation with MetaFix™ (°) (°) 1 30.5 1.11 -0.11 2 9.05 0.01 -0.14 3 27.25 0.10 0.19 4 19.69 -1.43 15.3 5 35.55 -1.15 -1.04 6 32.62 2.26 3.9 7 8.62 1.25 7.4 8 21.9 0.06 -0.6 9 13.65 -2.37 -1.61 10 10.85 -0.72 -2.46 Average 20.97 1.05 3.27 St Dev 10.17 0.85 4.79
Soft Tissue Balancing the Hip Joint: Offset and anteversion
Conclusion: • The early clinical results of a neck preservation are promising for improving patient outcomes and reducing hip dislocation in THA • Although conventional neck-sacrificing implants have their place in later revisions or in patients with poor bone quality, early or first time THA patients may benefit greatly from Neck preserving-type implants • Randomized controlled studies are required to gather more evidence concerning potential benefits • Longer-term studies will provide valuable data regarding the longevity of the implant in comparison to traditional designs.
Thank You
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