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Jahnke A, Köther-Herrmann J, Fonseca Ulloa CA, Harz T, Rickert M, Ishaque BA. Retrospective clinical and X-ray-based outcome analysis of a short-stem hip arthroplasty taking into account the operative learning curve over 7 years in the 3-year control course. Arch Orthop Trauma Surg 2023; 143:6589-6597. [PMID: 37418006 PMCID: PMC10542719 DOI: 10.1007/s00402-023-04977-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/27/2023] [Indexed: 07/08/2023]
Abstract
INTRODUCTION Self-monitoring is crucial to work progressively with a high-quality standard. A retrospective analysis is a valuable tool for studying the postoperative outcome of a prosthesis and for evaluating the learning process for the surgeon. MATERIALS AND METHODS The learning process of one surgeon was analysed in 133 cases of hip arthroplasty. These were divided into seven groups representing the surgical years 2008-2014. Over the course of 3 postoperative years, a total of 655 radiographs were analysed at regarding three radiological quality parameters (centrum-collum-diaphyseal angle (CCD angle), intramedullary fit&fill ratio (FFR), and migration) and ancillary outcome parameters (Harris Hip Score (HHS), blood loss, operating time, and complications). This period was divided into five times: 1st-day post-op, 6 M, 12 M, 24 M, and 36 M. Bivariate Spearman's correlation analysis and pairwise comparisons were performed. RESULTS The total collective achieved a proximal FFR of over 0.8. The distal prosthesis tip migrated and was located on the lateral cortex within the first months. The CCD angle initially showed a variation with a subsequent constant course. The HHS showed a significant increase (p < 0.001) to over 90 points postoperatively. Over time, the operating time and blood loss decreased. Intraoperative complications existed only at the beginning of the learning phase. A learning curve effect can be determined for almost all parameters by comparing the subject groups. CONCLUSIONS Operative expertise was shown to gain through a learning curve, whereby postoperative results corresponded to the system philosophy of the short hip stem prosthesis. The distal FFR and the distal lateral distance could represent the principle of the prosthesis, which overall could be an interesting approach for verification of a new parameter.
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Affiliation(s)
- Alexander Jahnke
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany
| | - Jan Köther-Herrmann
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany
| | - Carlos A Fonseca Ulloa
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany
| | - Torben Harz
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany
| | - Markus Rickert
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany
- Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstrasse 33, 35392, Giessen, Germany
| | - Bernd Alexander Ishaque
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany.
- Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstrasse 33, 35392, Giessen, Germany.
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Passano B, Oakley CT, Lutes WB, Incavo SJ, Park KJ, Schwarzkopf R. Clinical and Radiographic Outcomes of a Monoblock Fluted Titanium-Tapered Stem for Paprosky IIIa, IIIb, and IV Femoral Bone Defects. J Arthroplasty 2023:S0883-5403(23)00054-2. [PMID: 36731584 DOI: 10.1016/j.arth.2023.01.034] [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: 09/26/2022] [Revised: 01/21/2023] [Accepted: 01/23/2023] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Modern fluted titanium-tapered stems (FTTS) have been increasingly utilized to achieve primary stability in conversion and revision total hip arthroplasty with major femoral bone loss. This study sought to determine the radiographic and clinical outcomes of a monoblock FTTS in patients who had major femoral bone loss. METHODS A multicenter retrospective observational study of all total hip arthroplasty patients who received a monoblock FTTS who had up to 5-year radiographic follow-up was conducted. Only patients with femoral Paprosky classifications of IIIa, IIIb, and IV were included. Eighty-one monoblock FTTS were examined. Median clinical follow-up was 29 months (range, 18 to 58). Stem subsidence and loosening were assessed on most recent radiographs. All-cause revisions and stem survivals were assessed. RESULTS Median subsidence was 1.4 millimeters (mm) (range, 0 to 15.0). Sixteen (23.9%) and 3 (4.5%) stems had subsidence greater than 5 and 10 mm, respectively. All stems not acutely revised appeared stable, without evidence of loosening, at latest follow-up. Ten hips (12.3%) required reoperations. Of these, only 5 (6.2%) stems were removed; 4 due to periprosthetic joint infection and 1 for surgical exposure during acetabular revision. Kaplan-Meier analyses yielded an all-cause stem survivorship of 95.1% at 2-years and 87.1% at 4-years. Stem survivorships excluding septic causes was 98.8% at both 2 and 4 years. CONCLUSION Monoblock FTTS in complex femoral reconstruction cases showed encouraging clinical and radiographic results in patients who had severe femoral bone loss at median 29 months follow-up.
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Affiliation(s)
- Brandon Passano
- Department of Orthopedic Surgery, NYU Langone Hospital-Long Island, Mineola, New York
| | - Christian T Oakley
- Department of Orthopedic Surgery, NYU Langone Health, New York, New York
| | - William B Lutes
- Department of Orthopedic Surgery, Aurora Health Clinic, Kenosha, Wisconsin
| | - Stephen J Incavo
- Department of Orthopaedics and Sports Medicine, Houston Methodist, Houston, Texas
| | - Kwan J Park
- Department of Orthopaedics and Sports Medicine, Houston Methodist, Houston, Texas
| | - Ran Schwarzkopf
- Department of Orthopedic Surgery, NYU Langone Health, New York, New York
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Initial femoral stem position in cementless bipolar hemiarthroplasty for femoral neck fracture in elderly patients is associated with early implant subsidence: A radiographic analysis. Injury 2021; 52:1801-1806. [PMID: 34039470 DOI: 10.1016/j.injury.2021.05.006] [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: 01/07/2021] [Revised: 04/14/2021] [Accepted: 05/06/2021] [Indexed: 02/08/2023]
Abstract
BACKGROUND Bipolar hemiarthroplasty is a well-established treatment for displaced femoral neck fracture in elderly patients. Implant subsidence is a potential complication with cementless femoral stems, and smaller canal fill ratio has been reported as a radiographic risk factor. We aimed to determine the risk factors for subsidence, particularly the initial implant position relative to the resected medial calcar of proximal femur. METHODS We retrospectively reviewed all cementless bipolar hemiarthroplasties performed using a single proximally hydroxyapatite-coated femoral stem in patients with a minimum radiographic follow-up of 12 weeks between January 2017 and December 2018. The amount of subsidence (significant subsidence defined as ≥ 5 mm), canal fill ratio, and implant position relative to the point of resected medial calcar (position A: medial and superior to calcar; position B: lateral and superior to calcar; position C: lateral and inferior to calcar) were measured and analyzed. RESULTS One-hundred eighty patients were identified (mean age: 80.9 years). Significant subsidence was observed in 52 patients (28.9%). On multivariate analysis, older age, lower canal fill ratio, implant position B, C, and less medial overhang of stem were independent risk factors for early implant subsidence. The risk ratio of position B and C to position A was 5.13 (95% confidence interval, 2.23-11.80). CONCLUSION In our analysis, older age and lower canal fill ratio were associated with increased risk of subsidence, whereas implant with position A and more medial overhang were less prone to subsidence with the tapered proximally hydroxyapatite-coated implant.
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Kutzner KP, Donner S, Loweg L, Rehbein P, Dargel J, Drees P, Pfeil J. Mid-term results of a new-generation calcar-guided short stem in THA: clinical and radiological 5-year follow-up of 216 cases. J Orthop Traumatol 2019; 20:31. [PMID: 31673809 PMCID: PMC6823459 DOI: 10.1186/s10195-019-0537-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 08/23/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND In recent years, a variety of short stems have been introduced. To date, mid- and long-term results of calcar-guided short-stem designs have been rarely available. MATERIALS AND METHODS Two hundred and sixteen calcar-guided short stems were included in combination with a cementless cup in a prospective study. Patients were allowed full weight-bearing on the first day postoperatively. Harris hip score (HHS) as well as pain and satisfaction on visual analogue scale (VAS) were assessed during a median follow-up of 61.7 months. Standardised radiographs were analysed at predefined time points regarding radiological alterations such as bone resorption and remodelling, radiolucency, osteolysis and cortical hypertrophy using modified Gruen zones. RESULTS At mid-term follow-up, no revision surgery of the stem had to be performed in the whole collective. At 5 years, HHS was 97.8 (SD 4.7), satisfaction on VAS was 9.7 (SD 0.7), rest pain on VAS was 0.1 (SD 0.5), and load pain on VAS was 0.6 (SD 1.2). Compared to the 2-year results, femoral bone resorption increased significantly at the 5-year follow-up (3.9% versus 42.3%). Rate of femoral cortical hypertrophy remained stable, occurring in a total of 9 hips (4.5%). At the 5-year follow-up, 2 stems (1.0%) showed non-progressive radiolucent lines with a maximum width of 2 mm. Signs of osteolysis were not observed. Compared to the 2-year follow-up, no further subsidence was observed. CONCLUSIONS The rate of stem revision (0%) at the mid-term follow-up was remarkable and indicates the principle of using a calcar-guided short stem as being a safe procedure. However, signs of bone-remodelling, indicating some amount of stress-shielding, must be acknowledged at 5 years depending on stem alignment and type of anchorage. LEVEL OF EVIDENCE IV, Prospective observational study Trial registration German Clinical Trials Register, DRKS00012634, 07/07/2017 (retrospectively registered).
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Affiliation(s)
- Karl Philipp Kutzner
- Department of Orthopaedic Surgery and Traumatology, St. Josefs Hospital Wiesbaden, Beethovenstr. 20, 65189, Wiesbaden, Germany. .,Department for Orthopaedics and Traumatology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany.
| | - Stefanie Donner
- Department of Orthopaedic Surgery and Traumatology, St. Josefs Hospital Wiesbaden, Beethovenstr. 20, 65189, Wiesbaden, Germany
| | - Lennard Loweg
- Department of Orthopaedic Surgery and Traumatology, St. Josefs Hospital Wiesbaden, Beethovenstr. 20, 65189, Wiesbaden, Germany
| | - Philipp Rehbein
- Department of Orthopaedic Surgery and Traumatology, St. Josefs Hospital Wiesbaden, Beethovenstr. 20, 65189, Wiesbaden, Germany
| | - Jens Dargel
- Department of Orthopaedic Surgery and Traumatology, St. Josefs Hospital Wiesbaden, Beethovenstr. 20, 65189, Wiesbaden, Germany
| | - Philipp Drees
- Department for Orthopaedics and Traumatology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Joachim Pfeil
- Department of Orthopaedic Surgery and Traumatology, St. Josefs Hospital Wiesbaden, Beethovenstr. 20, 65189, Wiesbaden, Germany
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Outcomes of cerclage wiring to manage intra-operative femoral fracture occurring during cementless hemiarthroplasty in older patients with femoral neck fractures. INTERNATIONAL ORTHOPAEDICS 2019; 43:2637-2647. [DOI: 10.1007/s00264-019-04327-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/28/2019] [Indexed: 01/06/2023]
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Lee YK, Kim TY, Ha YC, Koo KH. To withhold or to implement bisphosphonate after cementless hip arthroplasty: a dilemma in elderly hip fracture patients. J Orthop Surg Res 2019; 14:66. [PMID: 30808386 PMCID: PMC6390618 DOI: 10.1186/s13018-019-1104-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 02/18/2019] [Indexed: 01/23/2023] Open
Abstract
Background Prior studies reported ambivalent effects of bisphosphonates on the fixation of cementless stem in hip arthroplasty patients. To set up the postoperative guide of bisphosphonate use after cementless hip arthroplasty, we investigated whether zoledronate has beneficial or negative effects in the stem migration and walking ability after cementless hemi-arthroplasty in elderly patients, who were operated due to femoral neck fracture. Methods We compared 59 patients (zoledronate group), who received zoledronate after cementless hemi-arthroplasty, and 66 patients (control group), who did not receive that agent. We evaluated stem subsidence, cortical porosis around the stem, and walking ability with the use of Koval’s categories at 2-year follow-up. Results No patient had more than 2 mm of stem subsidence in both groups. One patient in the control group had cortical porosis around the stem, but none in the zoledronate group. There were no significant differences in the postoperative Koval scores (p = 0.769) and in the proportion of walking recovery to pre-fracture status (p = 0.695) between the two groups. Conclusion We did not find neither beneficial nor negative effect of this agent in terms of stem fixation and walking ability. Zoledronate can be used after cementless hemi-arthroplasty to manage the osteoporosis in elderly patients.
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Affiliation(s)
- Young-Kyun Lee
- Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam, 13620, South Korea
| | - Tae-Young Kim
- Konkuk University Medical Center, Department of Orthopaedic Surgery, School of Medicine, Konkuk University, 120-1, Neungdong-ro, Gwangjin-gu, Seoul, 05030, South Korea.
| | - Yong-Chan Ha
- Department of Orthopaedic Surgery, College of Medicine, Chung-Ang University, 224-1 Heukseok-dong, Dongjak-gu, Seoul, 06973, South Korea
| | - Kyung-Hoi Koo
- Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam, 13620, South Korea
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Rinaldi G, Capitani D, Maspero F, Scita V. Mid-term results with a neck-preserving femoral stem for total hip arthroplasty. Hip Int 2018; 28:28-34. [PMID: 30755122 DOI: 10.1177/1120700018813216] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
INTRODUCTION: This prospective study aims to evaluate the mid-term clinical and radiological performance of a new short, neck-preserving femoral stem in total hip arthroplasty (THA). PATIENTS AND METHODS: 178 consecutive patients (190 hips) underwent THA from November 2008 to July 2016. Mean follow-up is 62.4 months. Women make up 41% of the cohort at a mean age of 50 ± 4 years, with primary hip osteoarthritis as the main complaint. All patients underwent radiological evaluation using the modified Gruen method, and clinical assessment via the Harris Hip Score (HHS), preoperatively and at 1, 6, 12, 24, 60, 80 and 106 months post-op. RESULTS: A mean HHS increase (from 50 ± 12 points preoperatively to 96 ± 4 at 62 months), together with painless articular improvement, was present at 6 months postoperatively indicating early functional recovery. Effective osteointegration and primary stability were present on radiographic analysis, without evidence of stress shielding or stem mal-positioning: subsidence amounting to <1 mm was present in 40% of implants immediately after surgery, with subsequent stabilisation within 6 months in all cases. Metaphyseal trabecular re-orientation in absence of symptomatic cortical hypertrophy or progressive radiolucency indicates physiological load transfer in the proximal femur. Stem-related revision surgery was necessary for 1.05% of all implants due to fracture and infection. No loosening, dislocations or mechanical failures were reported. CONCLUSIONS: All patients show excellent functional recovery and clinical outcomes at 62 months, demonstrating the role optimal primary stability and physiological joint reconstruction play in ensuring stable secondary fixation and long-term survival of a short, neck-preserving stem.
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Affiliation(s)
- Giampaolo Rinaldi
- 1 Joint Replacement Division, Department of Orthopedic Surgery and Trauma, ASST Niguarda Hospital, Milan, Italy
| | - Dario Capitani
- 1 Joint Replacement Division, Department of Orthopedic Surgery and Trauma, ASST Niguarda Hospital, Milan, Italy.,2 School of Medicine and Surgery, University of Milan, Italy
| | - Fabio Maspero
- 1 Joint Replacement Division, Department of Orthopedic Surgery and Trauma, ASST Niguarda Hospital, Milan, Italy
| | - Valentina Scita
- 1 Joint Replacement Division, Department of Orthopedic Surgery and Trauma, ASST Niguarda Hospital, Milan, Italy.,2 School of Medicine and Surgery, University of Milan, Italy
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Kabelitz M, Fritz Y, Grueninger P, Meier C, Fries P, Dietrich M. Cementless Stem for Femoral Neck Fractures in a Patient’s 10th Decade of Life: High Rate of Periprosthetic Fractures. Geriatr Orthop Surg Rehabil 2018; 9:2151459318765381. [PMID: 29623237 PMCID: PMC5881960 DOI: 10.1177/2151459318765381] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/28/2018] [Accepted: 02/15/2018] [Indexed: 01/22/2023] Open
Abstract
Background: Subsidence of cementless femoral stems in hemiarthroplasty (HA) and increased fracture rates are ongoing concerns of orthopedic surgeons when treating fractures in very old patients. Additionally, bone cement implantation syndrome may result in perioperative cardiac or pulmonary complications, especially in older patients, leading to morbidity and mortality. This study was performed to analyze possible subsidence and intraoperative fractures in a cohort of very old patients treated with cementless stems. Methods: We retrospectively analyzed a consecutive cohort of patients aged ≥90 years with femoral neck fractures treated by uncemented HA and an anterior minimally invasive approach. Immediate full-weight bearing was allowed postoperatively. Pelvic radiographs were examined for subsidence immediately postoperatively and 6 weeks later. Results: We treated 109 patients (74% women; mean age, 93 years; range, 90-102 years) by HA from January 2010 to March 2016. The 30-day mortality rate was 16%, and the morbidity rate was 47%. There were 11 (12%) intraoperative fractures: 8 (Vancouver B2) had to be addressed immediately during the primary operation, while 3 (1 Vancouver B1 and 2 Vancouver AG) were treated conservatively. One periprosthetic femoral fracture (Vancouver B1) was documented during follow-up. In 17 patients, subsidence of >2.0 mm (median, 3.9 mm; range, 2.5-9.0 mm) was documented. Conclusion: Early subsidence was low in this very old cohort treated with an uncemented stem and not showing a periprosthetic fracture. The risk of intraoperative periprosthetic fractures was high. The use of uncemented implants in osteoporotic bone continues to be an intervention with high risk and should only be performed by experienced surgeons. Level of Evidence: Level III, Therapeutic study.
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Affiliation(s)
- Method Kabelitz
- Department for Surgery, City Hospital Waid Zurich, Zurich, Switzerland
| | - Yannick Fritz
- Department for Surgery, City Hospital Waid Zurich, Zurich, Switzerland
| | | | - Christoph Meier
- Department for Surgery, Kantonsspital Winterthur, Winterthur, Switzerland
| | - Patrick Fries
- Department for Surgery, City Hospital Waid Zurich, Zurich, Switzerland
| | - Michael Dietrich
- Department for Surgery, City Hospital Waid Zurich, Zurich, Switzerland
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Radiographic alterations in short-stem total hip arthroplasty: a 2-year follow-up study of 216 cases. Hip Int 2016; 26:278-83. [PMID: 27102556 DOI: 10.5301/hipint.5000339] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/30/2015] [Indexed: 02/04/2023]
Abstract
INTRODUCTION In recent years a variety of short-stems have been introduced. Stable osteointegration is a key factor for a satisfactory long-term result. The purpose of this study was to evaluate postoperative radiological alterations and subsidence, as a result of using a newly developed device, over a 2-year follow-up. METHODS 216 short-stems were implanted in combination with a cementless cup. Patients were allowed full weight-bearing on the first day postoperatively. Pre- and postoperative x-rays were done using a standardised technique. Radiological alterations, such as bone resorption, radiolucency, osteolysis and cortical hypertrophy were detected and located using modified Gruen zones, and subsidence was measured via a conventional digital technique over a 2-year follow-up. In addition, Harris Hip Score (HHS), rest pain and load pain on the visual analogue scale (VAS) were assessed respectively. RESULTS At 2-year follow-up 6 stems (2.9%) showed nonprogressive radiolucent lines with a maximum width of 2 mm. Resorption of femoral bone stock was detected in a total of 8 cases (3.9%). Femoral cortical hypertrophy was seen in a total of 9 hips (4.4%). No patient showed osteolysis. A measureable subsidence of at least 2 mm was observed in a total of 15.7% (32 cases) after 6 weeks, corresponding to an initial settlement given full weight-bearing ambulation. Only 1.1% (2 cases) showed further progression at the 6-month follow-up, whereas at the 1- and 2-year follow-ups no further subsidence was observed. After 2 years HHS was 98.1 (65.0-100.0), rest pain on the VAS was 0.2 (0.0-7.0) while load pain was 0.4 (0.0-7.0). CONCLUSIONS The results of this radiographic analysis give support to the principle of using metaphyseal anchoring, calcar guided short-stems. The low incidence of bony alterations after a follow-up of 2 years indicates a physiological load distribution. After mild initial subsidence a stable osteointegration can be achieved over time.
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Brinkmann V, Radetzki F, Delank KS, Wohlrab D, Zeh A. A prospective randomized radiographic and dual-energy X-ray absorptiometric study of migration and bone remodeling after implantation of two modern short-stemmed femoral prostheses. J Orthop Traumatol 2015; 16:237-43. [PMID: 25666724 PMCID: PMC4559543 DOI: 10.1007/s10195-015-0335-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 01/11/2015] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The aim of this prospective randomized study was to analyze migration and strain transmission of the Metha™ and Nanos™ femoral prostheses. MATERIALS AND METHODS Between 1 January 2011 and 2 April 2013, 50 patients were randomized to receive short-stemmed femoral prostheses. Metha™ stems were implanted in 24 patients (12 female, 12 male; mean age 58.7 years; mean body mass index [BMI] 27.4) and Nanos™ stems in 26 patients (10 female, 16 male; mean age 59.7 years; mean BMI 27.1). Longitudinal stem migration, varus-valgus alignment, changes of center of rotation (COR), femoral offset and caput-collum-diaphyseal angle, leg length discrepancy, periprosthetic radiolucent lines incidence, and dual-energy X-ray absorptiometry (DEXA) scans were analysed after an average of 98 and 381 days. RESULTS There was no significant change of varus-valgus alignment or clinically relevant migration of the Metha™ or Nanos™ prostheses during postoperative follow-up. After 12.3 months, the DEXA scans showed small but significant differences of bone mineral density in Gruen zones 1 (minus ~8 %) and 6 (plus ~9 %) for the Metha™ and in Gruen zone 1 (minus ~14 %) for the Nanos™ (paired t test). Visual analog scale (VAS) and Harris Hip Score (HHS) improved significantly for both implants (Nanos™/Metha™ 12.3 months postoperatively HSS 96.5/96.2; VAS 0.7/0.8, respectively). COR or offset did not change significantly after surgery. CONCLUSIONS Neither implant showed signs of impaired osseointegration. DEXA demonstrated proximally located load transfer with only moderate proximal stress shielding. LEVEL OF EVIDENCE II.
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Affiliation(s)
- Volker Brinkmann
- Department of Orthopaedics and Traumatology, Faculty of Medicine, Martin-Luther-University of Halle-Wittenberg, Ernst-Grube-Strasse 40, 06120 Halle/Saale, Germany
| | - Florian Radetzki
- Department of Orthopaedics and Traumatology, Faculty of Medicine, Martin-Luther-University of Halle-Wittenberg, Ernst-Grube-Strasse 40, 06120 Halle/Saale, Germany
| | - Karl Stefan Delank
- Department of Orthopaedics and Traumatology, Faculty of Medicine, Martin-Luther-University of Halle-Wittenberg, Ernst-Grube-Strasse 40, 06120 Halle/Saale, Germany
| | - David Wohlrab
- Department of Orthopaedics and Traumatology, Faculty of Medicine, Martin-Luther-University of Halle-Wittenberg, Ernst-Grube-Strasse 40, 06120 Halle/Saale, Germany
| | - Alexander Zeh
- Department of Orthopaedics and Traumatology, Faculty of Medicine, Martin-Luther-University of Halle-Wittenberg, Ernst-Grube-Strasse 40, 06120 Halle/Saale, Germany
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