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Alqahtani Y, Somerville LE, Vasarhelyi EM, Howard JL, Lanting BA, Naudie DDR, MacDonald SJ, McCalden RW. Minimum 2-Year Outcomes of a Modern Monoblock Titanium Fluted Tapered Revision Stem for Complex Primary and Revision Total Hip Arthroplasty. J Arthroplasty 2024; 39:S208-S212. [PMID: 38521249 DOI: 10.1016/j.arth.2024.03.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 03/15/2024] [Accepted: 03/15/2024] [Indexed: 03/25/2024] Open
Abstract
BACKGROUND Modular titanium fluted tapered (TFT) stems have demonstrated excellent clinical success for femoral revision total hip arthroplasty (THA) surgery. This study reports the short-term outcomes of a novel modern monoblock TFT stem used for revision and complex primary THA with a minimum of 2 years of follow-up. METHODS We identified 126 patients who received a single monoblock TFT stem: 26 patients for complex THA (failed fracture fixation) and 100 patients for revision THA. The reasons for revision THA included 40 for previous periprosthetic joint infection, 42 for aseptic loosening, 9 for trunnionosis, and 9 for periprosthetic fractures. The Paprosky grading for femoral bone loss at the time of surgery and the measured subsidence of femoral stems at 3-month follow-up were determined. We evaluated the number and indications for reoperations. RESULTS The mean time from surgery was 3.9 years (range, 2.0 to 6.9). A paired t-test analysis showed significant improvement from preoperative versus postoperative clinical outcome scores (P < .001) for Harris Hip Score (38.76 ± 15.24 versus 83.42 ± 15.38), Western Ontario and McMaster Universities Arthritis Index (45.6 ± 19.0 versus 69.9 ± 21.3), Veterans RAND 12 Item Health Survey Physical component (31.7 ± 8.1 versus 37.8 ± 11.3), and Veterans RAND 12 Item Health Survey Mental component (48.2 ± 12.2 versus 51.6 ± 12.5). The Paprosky grading for femoral bone loss was Grade 1 (3.9%), Grade 2 (35.7%), Grade 3A (47.6%), Grade 3B (11.1%), and Grade 4 (1.6%) cases. There were 18 reoperations (14.7%), with 13 for periprosthetic joint infection (7 treated with implant retention and 6 treated with a 2-stage revision), 4 for instability, and 1 for acetabular aseptic loosening. There were no aseptic failures of the stem. CONCLUSIONS This novel modern monoblock TFT stem provided reliable femoral fixation and has increasingly supplanted the use of modular TFT stems for complex primary and revision surgery in our institution.
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Affiliation(s)
- Yousef Alqahtani
- Division of Orthopaedic Surgery, Department of Surgery, Clinical Fellow in Hip and Knee Adult Reconstruction, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - Lyndsay E Somerville
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - Edward M Vasarhelyi
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - James L Howard
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - Brent A Lanting
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - Douglas D R Naudie
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - Steven J MacDonald
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - Richard W McCalden
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
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Wang L. In-silico modelling of multi-strike insertion and torsional resistance of tapered revision hip stems: Insight into spline design philosophy. Med Eng Phys 2023; 118:104020. [PMID: 37536841 DOI: 10.1016/j.medengphy.2023.104020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 05/10/2023] [Accepted: 07/07/2023] [Indexed: 08/05/2023]
Abstract
Despite the clinical success of tapered splined titanium stems, a knowledge gap still exists between spline design and its primary mechanical stability, which is critical to the long-term success of revision hip arthroplasty. Additionally, almost all published pre-clinical studies relied on resource-intensive benchtop and cadaveric testing. Hence, the present study developed a novel computational model to investigate effects of spline geometry and configuration on axial and torsional stability of tapered stem. Dynamic explicit Finite Element Analysis coupled with a state-of-the-art adaptive meshing technique was used to simulate the highly non-linear contacts and large bony material deformations. Hybridising primary straight splines with secondary angled splines results in 41% and 10% increases of peak insertion force and post-seating moment than the predicate device for the same seating position. The primary straight splines cut at multiple circumferential bony locations, enhancing torsional stability; while the alternatively placed secondary angled splines form wedges with the bone, providing reliable seating and additional torsional resistance. To the best knowledge of the author, this is the first in-silico investigation of its kind to simulate multi-strike seating and torsional resistance of revision hip stems, offering an effective and efficient platform for future multi-factorial parametric study and uncertainty quantification.
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Affiliation(s)
- Lin Wang
- DePuy Synthes, St Anthony's Road, Leeds, LS11 8DT, United Kingdom.
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Pomeroy E, Lim J, Vasarhelyi EM, Naudie D, Lanting B, MacDonald SJ, McCalden RW, Howard JL. No Difference In Subsidence Between Modern Monoblock And Modular Titanium Fluted Tapered Femoral Stems. J Arthroplasty 2023:S0883-5403(23)00262-0. [PMID: 36963526 DOI: 10.1016/j.arth.2023.03.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/12/2023] [Accepted: 03/13/2023] [Indexed: 03/26/2023] Open
Abstract
BACKGROUND Subsidence remains a concern when utilizing tapered fluted titanium (TFT) femoral stems and may lead to leg length discrepancy, impingement, instability and failure to obtain osseointegration. This study aims to compare stem subsidence across three modern TFT stems. Our secondary aim was to investigate the influence of bicortical contact or 'scratch fit' on subsidence, as well as the role of intraoperative imaging in maximizing bicortical contact and preventing stem subsidence. METHODS A retrospective review of 271 hip arthroplasties utilizing modern TFT stems at a single institution was performed. Three stem designs were included in the analysis: one monoblock TFT stem (n=91) and two modular TFT stems (n=90; n=90). Patient demographics, Paprosky femoral bone loss classification, bicortical contact, utilization of intra-operative imaging, and stem subsidence (comparison of initial post-operative radiograph to the latest follow up radiograph - minimum three months) were recorded. RESULTS There was no statistically significant difference in overall subsidence (P=0.191) or the incidence of subsidence >5 millimeters between stems (P= 0.126). Subgroup analysis based on femoral bone loss grading showed no difference in subsidence between stems. Increased bicortical contact was associated with reduced subsidence (P=0.004). Intra-operative imaging was used in 46.5% (126 of 271) of cases; this was not correlated with bicortical contact (P=0.673) or subsidence (P=0.521). CONCLUSION All three modern TFT stems were highly successful and associated with low rates of subsidence, regardless of modular or monoblock design. Surgeons should select the stem that they feel is most clinically appropriate.
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Affiliation(s)
- E Pomeroy
- Consultant Orthopaedic Surgeon, Department of Trauma & Orthopaedics, University Hospital Waterford, Waterford, Ireland
| | - Jbt Lim
- Consultant Orthopaedic Surgeon, Department of Orthopaedic Surgery, Singapore General Hospital, Outram Road, S169608, Republic of Singapore
| | - E M Vasarhelyi
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - Ddr Naudie
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - B Lanting
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - S J MacDonald
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
| | - R W McCalden
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada.
| | - J L Howard
- Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University and London Health Sciences Centre, London, Ontario, Canada
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Pomeroy E, Flynn SO, Grigoras M, Murphy TP, Stavrakis AI, Rowan FE. Subsidence of monoblock and modular titanium fluted tapered stems in revision hip arthroplasty: A retrospective multicentre comparison study. J Clin Orthop Trauma 2022; 34:102021. [PMID: 36147379 PMCID: PMC9486022 DOI: 10.1016/j.jcot.2022.102021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 08/20/2022] [Accepted: 09/07/2022] [Indexed: 11/22/2022] Open
Abstract
Background Tapered, fluted, titanium (TFT) stems have shown good clinical outcomes in revision total hip arthroplasty (rTHA), however concerns exist regarding early subsidence. This study compares subsidence between a modern monoblock 3-degree and a modular 2-degree TFT stem in rTHA. Methods A retrospective, international multicentre comparative study was conducted including 64 rTHA in 63 patients. A monoblock TFT stem was used in 37 cases and a modular TFT stem was used in 27 cases. Patient demographics, Paprosky femoral bone loss classification, bicortical contact and stem subsidence were recorded at minimum four week follow up. Results There was no statistically significant difference in overall subsidence (p = 0.318) or the rate of subsidence >10 mm between stems. Mean subsidence was 2.13 mm in the monoblock group and 3.15 mm in the modular group. Two stems subsided >10 mm: one in each group. There was no difference in bicortical contact between groups (p = 0.98). No re-revisions were performed. Conclusions We found no difference in subsidence between the two stems. Surgeons may consider the use of monoblock stems in rTHA as they have comparably low rates of subsidence and eliminate the small but potentially catastrophic risk of implant fracture at modular junctions associated with modular stems.
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Affiliation(s)
- Eoghan Pomeroy
- Department of Orthopaedic Surgery, University Hospital Waterford, Waterford, Ireland
| | - Seán O. Flynn
- Department of Orthopaedic Surgery, University Hospital Waterford, Waterford, Ireland
| | - Mihai Grigoras
- Department of Orthopaedic Surgery, University Hospital Waterford, Waterford, Ireland
| | - Terence P. Murphy
- Department of Orthopaedic Surgery, University Hospital Waterford, Waterford, Ireland
| | - Alexandra I. Stavrakis
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, 76-143 CHS, Los Angeles, CA, 90095-6902, USA
| | - Fiachra E. Rowan
- Department of Orthopaedic Surgery, University Hospital Waterford, Waterford, Ireland
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Gkiatas I, Malahias MA, Xiang W, Meyers KN, Torres LA, Tarity TD, Rodriguez JA, Bostrom MP, Wright TM, Sculco PK. How Does Contact Length Impact Titanium Tapered Splined Stem Stability: A Biomechanical Matched Pair Cadaveric Study. J Arthroplasty 2021; 36:3333-3339. [PMID: 33958253 DOI: 10.1016/j.arth.2021.04.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/09/2021] [Accepted: 04/14/2021] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Titanium tapered stems (TTS) achieve fixation in the femoral diaphysis and are commonly used in revision total hip arthroplasty. The initial stability of a TTS is critical, but the minimum contact length needed and impact of implant-specific taper angles on axial stability are unknown. This biomechanical study was performed to better guide operative decision-making by addressing these clinical questions. METHODS Two TTS with varying conical taper angles (2° spline taper vs 3.5° spline taper) were implanted in 9 right and left matched fresh human femora. The proximal femur was removed, and the remaining femoral diaphysis was prepared to allow for either a 2 cm (n = 6), 3 cm (n = 6), or 4 cm (n = 6) cortical contact length with each implanted stem. Stepwise axial load was then applied to a maximum of 2600N or until the femur fractured. Failure was defined as either subsidence >5 mm or femur fracture. RESULTS All 6 femora with 2 cm of stem-cortical contact length failed axial testing, a significantly higher failure rate (P < .02) than the 4 out of 6 femora and all 6 femora that passed testing at 3 cm and 4 cm, respectively, which were not statistically different from each other (P = .12). Taper angle did not influence success rates, as each matched pair either succeeded or failed at the tested contact length. CONCLUSION 4 cm of cortical contact length with a TTS demonstrates reliable initial axial stability, while 2 cm is insufficient regardless of taper angle. For 3 cm of cortical contact, successful initial fixation can be achieved in most cases with both taper angle designs.
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Affiliation(s)
- Ioannis Gkiatas
- Stavros Niarchos Foundation Complex Joint Reconstruction Center, Hospital for Special Surgery, New York, NY
| | - Michael-Alexander Malahias
- Stavros Niarchos Foundation Complex Joint Reconstruction Center, Hospital for Special Surgery, New York, NY
| | - William Xiang
- Stavros Niarchos Foundation Complex Joint Reconstruction Center, Hospital for Special Surgery, New York, NY
| | - Kathleen N Meyers
- Department of Biomechanics, Hospital for Special Surgery, New York, NY
| | - Lisa A Torres
- Department of Biomechanics, Hospital for Special Surgery, New York, NY
| | - T David Tarity
- Stavros Niarchos Foundation Complex Joint Reconstruction Center, Hospital for Special Surgery, New York, NY
| | - Jose A Rodriguez
- Stavros Niarchos Foundation Complex Joint Reconstruction Center, Hospital for Special Surgery, New York, NY
| | - Mathias P Bostrom
- Stavros Niarchos Foundation Complex Joint Reconstruction Center, Hospital for Special Surgery, New York, NY
| | - Timothy M Wright
- Department of Biomechanics, Hospital for Special Surgery, New York, NY
| | - Peter K Sculco
- Stavros Niarchos Foundation Complex Joint Reconstruction Center, Hospital for Special Surgery, New York, NY
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Butler Ransohoff C, Wanner R, Solinger T, Gautier E, Eijer H, Wahl P. The different failure modes of the connecting elements of the modular hip arthroplasty revision stem Revitan. J Mech Behav Biomed Mater 2021; 123:104778. [PMID: 34416537 DOI: 10.1016/j.jmbbm.2021.104778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/23/2021] [Accepted: 08/10/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Fracture of the femoral stem is the cause of ~1 % of revisions after total hip arthroplasty. The risk increases intrinsically with modularity, whereby modularity is particularly useful in revision arthroplasty. We present 7 cases of failure of a specific modular, tapered, fluted, titanium alloy Revitan stem and analyse the different failure modes. METHODS Retrospective review of all Revitan stems revised at our institutions due to implant failure and analysis of clinical presentation, diagnostic workup, and failure mode. The retrieved components were analyzed by optical and scanning electron microscopy. RESULTS A total of 7 cases were included. There was a significant time lag between symptom onset and correct diagnosis. Conventional radiographs and low-dose CT scans (CT scout imaging) were decisive for diagnosis. All failures occurred at the level of the connection between the proximal component and the distal part of the stem. Three different failure modes were identified: loosening of the proximal component, fatigue fracture of the connection pin, and distal loosening of the connection pin. No alterations of the microstructure or deviation from manufacturing specifications regarding dimensions were observed. Failure was caused by mechanical overload. CONCLUSION Conventional radiographs are the mainstay in identifying failed modular stems. Repeated radiographs and low-dose CT scans may be helpful additions. No single modification of the connection will address all possible failure modes. Modularity of revision stems offers advantages up until insertion of the definitive stem. Monoblock definitive stems might overcome the potential mechanical weaknesses of modularity and should be considered in relatively young, heavy and active patients.
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Affiliation(s)
| | - Ronald Wanner
- Department of Orthopaedics, Regional Hospital Emmental, Burgdorf, Switzerland
| | - Theo Solinger
- Department of Orthopaedic Surgery, HFR Fribourg - Cantonal Hospital, Fribourg, Switzerland; Orthopaedic Clinic Rosenberg, St. Gallen, Switzerland
| | - Emanuel Gautier
- Department of Orthopaedic Surgery, HFR Fribourg - Cantonal Hospital, Fribourg, Switzerland
| | - Henk Eijer
- Department of Orthopaedics, Regional Hospital Emmental, Burgdorf, Switzerland
| | - Peter Wahl
- Department of Orthopaedic Surgery, HFR Fribourg - Cantonal Hospital, Fribourg, Switzerland; Division of Orthopaedics and Traumatology, Cantonal Hospital Winterthur, Winterthur, Switzerland
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Ellenrieder M, Souffrant R, Schulze C, Kluess D, Mittelmeier W, Bader R. Primary stability of a cementless modular revision hip stem in relation with the femoral defect size: A biomechanical study. J Orthop Surg (Hong Kong) 2021; 28:2309499020948991. [PMID: 32909886 DOI: 10.1177/2309499020948991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
PURPOSE Cementless modular fluted hip stems are commonly used in revision arthroplasty. Nevertheless, there is a wide spectrum of recommendations concerning the minimum bone stock required to enable osseous ingrowth and implant-bone micromotions <100 µm. This experimental study investigated the primary stability of a tapered cementless fluted revision stem depending on different types of bone defects. METHODS Implant-bone interface movements with a bimodular stem were examined under cyclic axial and torsional loading using composite femora. In four degrees of freedom, the implant subsidence and micromotions were captured with linear variable differential transformers for the intact femora and seven different defects ranging from Paprosky type I to type IIIB. RESULTS With a 7-cm length of intact diaphysis proximal to the isthmus (Paprosky IIIA), mean implant-bone micromotions of 66 µm occurred. An implant-bone contact zone of only 5 cm (Paprosky IIIA) resulted in micromotions notably over 100 µm and significantly increased subsidence (p < 0.05). With a Paprosky IIIB defect (3 cm of intact diaphysis) rotational instability occurred in all specimens. CONCLUSIONS Aside from critically increased interfacial micromotions (>100 µm), rotational instability emerged as a mechanism of fixation failure when the implant-bone contact zone was only 5 cm or less. Hence, future studies investigating the implant fixation in the case of femoral bone defects should consider both axial and torsional loading. With regard to the clinical application, our data suggest maintaining 7 cm of diaphyseal implant-bone contact for a safe anchorage of cementless fluted hip revision stems.
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Affiliation(s)
- Martin Ellenrieder
- Department of Orthopaedics, 9187University Medicine Rostock, Rostock, Germany
| | - Robert Souffrant
- Department of Orthopaedics, 9187University Medicine Rostock, Rostock, Germany
| | - Christian Schulze
- Department of Orthopaedics, 9187University Medicine Rostock, Rostock, Germany
| | - Daniel Kluess
- Department of Orthopaedics, 9187University Medicine Rostock, Rostock, Germany
| | - Wolfram Mittelmeier
- Department of Orthopaedics, 9187University Medicine Rostock, Rostock, Germany
| | - Rainer Bader
- Department of Orthopaedics, 9187University Medicine Rostock, Rostock, Germany
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Li JJ, Tian DM, Yang L, Zhang JY, Hu YC. Influence of a metaphyseal sleeve on the stress-strain state of a bone-tumor implant system in the distal femur: an experimental and finite element analysis. J Orthop Surg Res 2020; 15:589. [PMID: 33298115 PMCID: PMC7724731 DOI: 10.1186/s13018-020-02025-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 10/14/2020] [Indexed: 12/03/2022] Open
Abstract
Background Aseptic loosening of distal femoral tumor implants significantly correlates with the resection length. We designed a new “sleeve” that is specially engaged in the metaphysis at least 5 cm proximal to the knee joint line to preserve as much bone stock as possible. This study investigates the influence of a metaphyseal sleeve on the stress-strain state of a bone tumor implant system in the distal femur. Methods Cortex strains in intact and implanted femurs were predicted with finite element (FE) models. Moreover strains were experimentally measured in a cadaveric femur with and without a sleeve and stem under an axial compressive load of 1000 N. The FE models, which were validated by linear regression, were used to investigate the maximal von Mises stress and the implanted-to-intact (ITI) ratios of strain in the femur with single-legged stance loading under immediate postoperative and osseointegration conditions. Results Good agreement was noted between the experimental measurements and numerical predictions of the femoral strains (coefficient of determination (R2) ≥ 0.95; root-mean-square error (RMSE%) ≈ 10%). The ITI ratios for the metaphysis were between 13 and 28% and between 10 and 21% under the immediate postoperative and osseointegration conditions, respectively, while the ITI ratios for the posterior and lateral cortices around the tip of the stem were 110% and 119% under the immediate-postoperative condition, respectively, and 114% and 101% under the osseointegration condition, respectively. The maximal von Mises stresses for the implanted femur were 113.8 MPa and 43.41 MPa under the immediate postoperative and osseointegration conditions, which were 284% and 47% higher than those in the intact femur (29.6 MPa), respectively. Conclusions This study reveals that a metaphyseal sleeve may cause stress shielding relative to the intact femur, especially in the distal metaphysis. Stress concentrations might mainly occur in the posterior cortex around the tip of the stem. However, stress concentrations may not be accompanied by periprosthetic fracture under the single-legged stance condition.
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Affiliation(s)
- Jian-Jun Li
- Tianjin Medical University, 22 Qixiangtai Road, Tianjin, People's Republic of China.,Department of Bone Oncology, Tianjin Hospital, 406 Jiefang Southern Road, Tianjin, People's Republic of China.,Department of Bone Trauma, Second Hospital of Tangshan, 22 Jianshe North Road, Tangshan, Hebei, People's Republic of China
| | - Dong-Mu Tian
- Beijing Weigao Yahua Artificial Joint Development Company, 7 Niuhui Street, Shunyi, Beijing, People's Republic of China
| | - Li Yang
- Tianjin Medical University, 22 Qixiangtai Road, Tianjin, People's Republic of China
| | - Jing-Yu Zhang
- Department of Bone Oncology, Second Hospital of Tangshan, 22 Jianshe North Road, Tangshan, Hebei, People's Republic of China
| | - Yong-Cheng Hu
- Department of Bone Oncology, Tianjin Hospital, 406 Jiefang Southern Road, Tianjin, People's Republic of China.
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Ellenrieder M, Souffrant R, Schulze C, Mittelmeier W, Bader R. Micromotion and subsidence of a cementless conical fluted stem depending on femoral defect size - A human cadaveric study. Clin Biomech (Bristol, Avon) 2020; 80:105202. [PMID: 33129564 DOI: 10.1016/j.clinbiomech.2020.105202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 09/09/2020] [Accepted: 10/19/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Cementless modular endoprostheses with tapered fluted stems cover a wide spectrum of femoral defects in reconstructive surgery of the hip. Nevertheless, for these hip stems the recommendations concerning the minimum diaphyseal anchorage distance differ widely. The present experimental study investigated the primary stability of a conical fluted revision stem depending on different types of femoral bone defects. METHODS Using six fresh frozen human femora, the relative movement of a bi-modular revision stem within the implant-bone interface was examined under cyclic loading conditions. Implant subsidence as well as micromotions at the bone-implant interface were captured with linear variable differential transformers for the intact femora and three different defects ranging from Paprosky type II to type IIIB. FINDINGS Compared to the intact femur, the infliction of a Paprosky type IIIB defect (3 cm of intact diaphysis) notably increased mean stem subsidence (13-389 μm per 500 load cycles; P = 0.116) but the mean interface micromotion vector sum remained unchanged (50 μm vs. 53 μm). In Paprosky IIIB defects the subsidence component resulting from rotation (horizontal plane) was significantly higher than with the intact femur and a Paprosky II defect (P ≤ 0.041). INTERPRETATION With optimal bone quality and ideal femur preparation a 3 cm conical fixation was sufficient to meet the set criteria of bony ingrowth in vitro. A conical fixation of 7 cm should be recommended to limit rotational subsidence, especially in case of impaired diaphyseal bone quality or expected difficulties with partial weight-bearing.
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Affiliation(s)
- Martin Ellenrieder
- Department of Orthopaedics, University Medicine Rostock, Doberaner Straße 142, D-18057 Rostock, Germany.
| | - Robert Souffrant
- Department of Orthopaedics, University Medicine Rostock, Doberaner Straße 142, D-18057 Rostock, Germany.
| | - Christian Schulze
- Department of Orthopaedics, University Medicine Rostock, Doberaner Straße 142, D-18057 Rostock, Germany.
| | - Wolfram Mittelmeier
- Department of Orthopaedics, University Medicine Rostock, Doberaner Straße 142, D-18057 Rostock, Germany.
| | - Rainer Bader
- Department of Orthopaedics, University Medicine Rostock, Doberaner Straße 142, D-18057 Rostock, Germany.
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