Total hip arthroplasty in Cambodia – Our experience of two hundred and fifty six consecutive total hip arthroplasties in a low-income country & the challenge of service delivery in this setting

The Children's Surgical Centre has performed 256 THAs since 2007, We aim to assess the outcome of arthroplasty in a LMIC. Primary outcome: all cause of re-operation, Secondary outcome: any other complication. A retrospective review of all consecutive THA since 2007 was conducted. Electronic and physical case notes were reviewed. Statistical analysis was performed using MedCalc. 256 THA. Mean age: 43, gender M2:1F. Common pathologies include (1) AVN (44%), (2) OA (11%) and (3) DDH (11%). Revision rate 13%. Time to revision was 2.8 years (0–9). Common revision reasons: (1) stem fracture (5.8%), (2) aseptic loosening (4.8%) and (3) infection (2.7%). Complications were identified in 85 patients (33.2%). Common complications included (1) aseptic loosening (10.5%) (2) stem fracture (5.8%) and (3) dislocation (5.8%). Patients at CSC benefit from THA, the complication rates at CSC are declining suggesting the apex of the ‘learning curve’ has passed. Cheap poorly manufactured implants continue to cause catastrophic failure.

Physical Properties and Failure Analysis for Bolts in the Diaphragm Valve by Micro Morphology and Metallographic Test

The reasons leading to the fracture of 17-4PH stainless steel bolts in the isolation valve of a power plant was analysed by means of morphology analysis, chemical analysis, hardness test, metallographic test, pitting corrosion test and intergranular corrosion test, SEM and other detection means. The results show that there are many corrosion pits on the surface of the valve stem in the seawater system, the corrosion pits is extend and propagation in intergranular cracking. The main reasons to valve stem fracture are the low corrosion resistance of the material and the improper aging process of heat treatment.

Retrieval analysis of neck fracture on uni-modular total hip arthroplasty stems: The contributions of material processing and stem design

Total hip arthroplasty stem fracture is an important contributor to morbidity rate and increases the cost of revision surgery. Failure is usually caused by issues related to overload, inadequate stem support, inappropriate stem design or dimensions and material processing. In this study, the role of the relationship between material characterization and biomechanical performance in the fracture of retrieved stems was explored. The stems were manufactured with forged stainless steel, had the same length, 12/14 trunnion, and 28-mm head. These stems were evaluated by macroscopic and microscopic examination to identify the causes of premature failure. Each stem was sectioned into four regions, and the cross-sections were used for the microhardness and grain size analysis. Finite element analysis (FEA) was carried out, considering the stem positioned at the femur, a musculoskeletal model, and biomechanical loading. All stems had fractured through a fatigue mechanism, mainly a unidirectional bending loading condition, with crack nucleation on the lateral side and propagation on the medial side. The numerical analysis revealed maximum mechanical stress on the lateral side of the stem neck, but this was below the yield stress calculated via the hardness. The use of a shorter head neck length could reduce the maximum mechanical stress at the neck. At a cross-section near the plane of the stem fracture, the hardness was lower than that normally reported by the ASM, and there were heterogonous and coarse grain sizes on the lateral side. The main cause of failure of the two stems analyzed was a combination of low hardness and coarse grain size, due to inappropriate materials processing, worsen by a high level of stress on the lateral side of the neck due to the large stem-head offset selected by the orthopedic surgeon.

Femoral Stem Fracture and Successful Reimplantation Using Femoral Window Technique in Canine Cemented Total Hip Replacement: Case Report

A fractured stem is a very rare, late complication in total hip replacement procedure in dogs. Here, we present one case after cemented total hip replacement with successful reimplantation, including clinical signs and radiographic findings.

Analysis of the Exeter V40 femoral stem prosthesis fracture

Aims The Exeter V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing implant fractures between the Exeter V40 series; 125 mm and conventional length stem systems. Methods A systematic literature search was performed adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. In parallel, we performed a retrospective single centre study of Exeter V40 femoral stem prosthetic fractures between April 2003 and June 2020. Results There are 25 reported cases of such prosthetic fractures confined to small case series and case reports within the literature. We report an additional 19 cases to the literature (mean age 66.3 years (SD 11.7); 12 (63%) females; BMI 32.9 kg/m2 (SD 5.9)). The mean time from index procedure to fracture was 7.8 years (SD 3.6; 2.5 to 16.3). Exeter V40 stem fracture incidence was 0.15% and 1.21% for primary and revision arthroplasty, respectively. Incidence was significantly higher in revision arthroplasty (p < 0.001) and 125 mm length stems compared to ≥ 150 mm length stems (1.25% vs 0.13%, respectively; p < 0.001). When comparing different stem length cohorts, 125 mm short-stems were associated with stem-body fractures (92% vs 29%; p = 0.0095), earlier time to fracture (6.2 years vs 11.0 years; p = 0.0018), younger patient age at time of fracture (62.7 years vs 72.6 years; p = 0.037), and female sex (75% vs 43%; p = 0.326). Conclusion This complication remains rare, although we report a significantly higher incidence at up to 17 years follow-up than in the literature. Short 125 mm length Exeter V40 stems undoubtedly have a role in restoring anatomy and biomechanics in smaller femoral geometries, although the surgeon has to appreciate the higher risk of stem fracture and the associated predisposing factors which may necessitate particular attention to surgical technique and planning. Cite this article: Bone Jt Open 2021;2(6):443–456.

Femoral Stem Fracture in Hip Revision Arthroplasty: A Systematic Literature Review of the Real-World Evidence

Background Total hip arthroplasty (THA) presents as an excellent treatment for the osteoarthritic hip, demonstrating good survival rates. However, aseptic loosening and infection are the main causes of operative revision. The methods used in revision surgery are non-modular or modular THA implants. In addition to the abovementioned revision reasons for THA, this treatment could be associated with the possibility of femoral stem fracture, especially in the modular system. The topic of material failure has been focused on in the public media. The question arises as to how such media reports correlate with the published literature. The observed mentioned number of cases concerning a femoral stem fracture vary between one single case and up to 18.5% within a clinical study, thus presenting an inhomogeneous data situation with a large span. The specific aim of this systematic review is to establish facts and clarify the number of unforeseen events of a femoral stem fracture based on peer review articles and registry data. This clarification is important to us, as these media reports have led to uncertainty among patients. Methods A systematic review was performed in accordance with the PRISMA statement. Peer review articles in English and German, presenting original articles, meta-analyses, or case reports, were searched from the turn of the millennium up to December 2019. Only articles that reported a femoral stem component fracture, with content of clinical data as well as register data, were included. Relevant papers published after the defined research time frame were taken into account within the discussion. Results In total, 218 fractures of a femoral stem (141 primary and 77 revision THA) component could be identified within the selected literature. Most cases of a femoral stem fracture occurred in the modular THA implants compared to the non-modular stems. Regarding revision THA, in summary, 77 implants, presenting 23 non-modular and 54 modular implants, failed by means of femoral stem fracture. A review of 11 National Joint Registries shows a revision rate between 0.04 and 0.05% in only 2 registers according to the specific subject of a femoral stem fracture. For the remaining 9 registers, however, detailed information is lacking and only nonspecific information such as a generic “implant failure” or “other reason” (which can cover a multitude of causes) is supplied. Conclusion A femoral stem fracture presents a devastating complication for the patient, the surgeon as well as for the manufacturer of the implant. Modular THA implants play an increasingly valuable role concerning restoration of individual anatomy in modern THA revision surgery, especially within complex cases. Regarding revision procedures, data suggests a lower risk of femoral stem fracture for modular implants compared to primary procedures, while the risk of fracture for non-modular implants seems to increase during revision. Ultimately, it cannot be proven whether this is actually applicable, since the absolute number of implanted prosthesis systems is not known. Various implant-, patient-, and surgeon-related factors may lead to these reported femoral stem fractures. However, this systematic review suggests that this is, in general, a rare complication.

Fatigue fracture of an uncemented Zweymüller femoral stem at the neck–shoulder junction

A fracture through the neck of the femoral stem in total hip arthroplasty is extremely rare. We report a neck fracture of a cementless Zweymüller stem, one of the most implanted stems worldwide. According to our knowledge, this is the first thorough case description of a neck fracture of a cementless Zweymüller stem. The case concerns a 53-year-old man, with a body weight of 103 kg and a body mass index of 31. We consider potential risk factors for a femoral stem fracture, such as patient-related factors, suboptimal implant positioning, surgical technique and implant characteristics.

Tapered, fluted, modular, titanium stems in Vancouver B periprosthetic femoral fractures: an analysis of 87 consecutive revisions

Aims: One of the instruments in the orthopaedic surgeon’s armamentarium to face the challenges associated with periprosthetic fracture around the stem of a hip replacement is the tapered, fluted, modular, titanium (TFMT) stem. Our aim was to study its clinical and radiological outcomes. Patients and Methods: During the period 2010–2016 86 patients (55 females; median age 78.2 years; mean BMI 26.3 kg/m2; median ASA classification 2) underwent 87 revisions for a Vancouver B periprosthetic fracture using a Stryker Restoration Cone-Conical stem. Results: After a median follow-up of 2.9 years no stem had to be revised and no case of stem fracture was found. Dislocation was the most common complication and occurred in 18% of patients. Other major complications were deep infection ( n = 4), subsidence >5 mm ( n = 7), and nonunion ( n = 5). 3-month and 1-year mortality was 10% and 15% respectively and was strongly correlated with age, deep infection, and ASA classification. The median EQ-5D health state index at final follow-up was 0.78 and all patients were ambulatory. Conclusions: The complication most commonly encountered was dislocation and can likely be prevented by the use of large heads, adequate reduction and fixation of the trochanteric area and restoration of the native anatomy. Contrary to previous concerns, fracture and subsidence of these modular stems do not appear to be a significant problem in this geriatric population.

History, treatment and analysis of a rare form of Exeter stem fracture

The Exeter stem by Stryker has become one of the most successful and widely used stems in modern cemented hip arthroplasty. We present a case of a rare stem fracture which was treated by ‘cement-in-cement’ revision arthroplasty technique. The patient, an 87-year-old man, presented with left hip pain and an inability to weight bear following a cracking sensation when he was standing to dress himself. The patient denied history of fall or trauma. On examination he was noted to have a shortened externally rotated left lower limb without neurovascular compromise. On pelvic radiograph he was noted to have an incomplete stem fracture of his left-sided total hip replacement. He was treated with a cement-in-cement revision. Postoperatively the stem was sent for analysis in the London Implant Retrieval Centre. This is an example of a rare form of stem fatigue failure treated with a well-described technique in revision arthroplasty.