Aims. There are limited long-term studies reporting on outcomes of the Zimmer Modular Revision (ZMR) stem, and concerns remain regarding failure. Our primary aim was to determine long-term survival free from all-cause revision and stem-related failure for this modular revision stem in revision total hip arthroplasty (THA). Secondary aims included evaluating radiological and functional outcomes. Methods. We retrospectively identified all patients in our institutional database who underwent revision THA using the ZMR system from January 2000 to December 2007. We included 106 patients (108 hips) with a mean follow-up of 14.5 years (2.3 to 22.3). Mean patient age was 69.2 years (37.0 to 89.4), and 51.9% were female (n = 55). Indications for index revision included aseptic loosening (73.1%), infection (16.7%), fracture (9.3%), and stem fracture (0.9%). Kaplan-Meier analysis was used to determine the all-cause and stem-related failure revision-free survival. At most recent follow-up, Oxford Hip Scores (OHS) were collected, and radiological stem stability was determined using the Engh classification. Results. A total of 17 hips (15.7%) underwent re-revision of any component. Indications for re-revision were stem failure (35.3%; n = 6), infection (29.4%; n = 5), instability (29.4%; n = 5), and acetabular aseptic loosening (5.9%; n = 1). The five- and 15-year all-cause survival was 89.7% (95% confidence interval (CI) 86.7 to 92.7) and 83.3% (95% CI 79.6 to 87.0), respectively. There were six re-revisions (5.6%) for stem failure; five for stem fracture and one for aseptic loosening. The five- and 15-year survival free from stem-related failure was 97.2% (95% CI 95.6 to 98.8) and 94.0% (95% CI 91.6 to 96.4), respectively. At final follow-up, the mean OHS was 36.9 (8.0 to 48.0) and 95.7% (n = 66) of surviving modular revision stems were well-fixed in available radiographs. Conclusion. Femoral revision with the ZMR offers satisfactory long-term all-cause revision-free survival, good survival free of stem-related failure, and favourable clinical outcomes. Stem fracture was the most common reason for stem-related failure and occurred both early and late. This highlights the importance of both early and long-term surveillance for stem-related failure. Cite this article: Bone Joint J 2024;106-B(5 Supple B):112–117

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/m. 2. (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

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. A systematic literature search was performed adhering to PRISMA criteria. In parallel we performed a retrospective single centre study of Exeter. ™. V40 femoral stem prosthetic fractures between April 2003– June 2020. 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 ± 11.7 years; 12 female [63%]; body mass index 32.9 ± 5.9 kg/m. 2. ). The mean time from index procedure to fracture was 7.8 years (2.5–16.3, ±3.6). Exeter V40 stem fracture incidence was 0.27%. Incidence was significantly higher in 125 mm length stems compared to ≥150 mm length stems (1.26% vs 0.13%, respectively, p <0.001) and revision arthroplasty (1.209% vs 0.149%, p <0.001). When comparing different stem length cohorts, 125-mm short-stem were associated with stem body fractures (92% vs 29%, p = 0.0095), earlier time to fracture (6.2 vs 11.0 years, p = 0.0018), younger patient age at time of fracture (62.7 vs 72.6 years old, p = 0.037) and female sex (75% vs 43%, p = 0.33). This case series in conjunction with the systematic review provides evidence stem morphology plays a role in femoral implant fracture. This complication remains rare, although we report a significantly higher incidence at up to 17 years follow-up than in the literature. As femoral geometries remain the same, increasing BMIs in THR patients should raise concern. 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 meticulous surgical technique and planning

The purpose of this study was to determine long-term survival free from all-cause revision and stem-related failure, as well as radiographic and functional outcomes of the ZMR stem in revision THA. We retrospectively identified all patients in our institutional database who underwent revision THA using the ZMR Revision Hip system from the year 2000 to 2007 (minimum two-year follow-up). Of the 112 ZMR hips (110 patients) identified, a total of 106 hips (104 patients) met inclusion criteria. The mean study follow-up 13.9 years (range 2–22). Indications for index ZMR revision included aseptic loosening (72.1%), periprosthetic joint infection (17.3%), periprosthetic fracture (9.6%), and stem fracture (1.0%). Kaplan-Meier analysis was used to determine the all-cause and stem-related failure revision-free survival. Validated patient reported outcomes were collected and available radiographs were reviewed to determine implant stability. A total of 17 hips (16.0%) underwent a re-revision of any component. The indications for re-revision were stem failure (35.3%), infection (29.4%), instability (29.4%), and aseptic loosening of the acetabular component (5.9%). The five- and 15-year all-cause survivorship was 89.5% (95% CI 86.5–92.5) and 83.0% (95% CI 79.2–86.8), respectively. There were six re-revisions for stem failure (5.7%); five for stem fracture and one for aseptic loosening. The average time to stem failure was 4.6 years (range 1.3–8.2). The five- and 15-year survivorship free from stem-related failure was 97.2% (95% CI 95.6–98.8) and 93.9% (95% CI 91.5–96.3), respectively. At final follow-up the mean Oxford hip score was 36.9 and all surviving ZMR stems were well fixed on radiographs. Femoral revision with the ZMR stem offers satisfactory long-term survivorship and promising clinical outcomes. Although uncommon, stem fracture was the most common reason for stem-related failure

Implant fracture of modular revision stems is a major complication after total hip arthroplasty revision (rTHA). Studies looking at specific modular designs report fracture rates of 0.3% to 0.66% whereas fractures of monobloc designs are only reported anecdotally. It is unclear whether the overall re-revision rate of modular designs is higher and if, whether stem fractures or other revision reasons are responsible for this elevation. All revisions within 5 years after implantation of a revision stems (n. 0. =13,900; n. 5. =2506) were analysed using Cox regression with design (modular: n=17, monobloc: n=27), BMI, Sex and Elixhauser Score as independent variables. One stage and two stage revisions were analysed separately (1-stage: modular n= 7,102; monobloc n= 4,542; 2-stage: 1,551 / 704). The revision volume of the hospitals was also considered (low: <20 revisions, medium: 21–50 revisions, high: >50 revisions). For the 1-stage revisions, the re-revision risk after 4 years was 14,3% [13.2%, 15.5%] for monobloc and 17.4% [16.40%, 18.40%] for modular stems (p< 0.001). Stem fracture was the reason for re-revision in 2.4% of the modular (fracture rate 0.42%) and 0.6% of the monobloc revisions. The difference in re-revision rates between the designs was mainly due to differences in dislocation and stem loosening. For the 2-stage revisions, the revision risks for either design were similar (21.7% [18,5%, 25.4%] vs. 23.0% [20.8%, 25.4%]; p=0.05). Patient characteristics influenced the comparison between the two designs in the 1-stage group but very little in the 2-stage group. Modular revision stem fractures only contribute very minor to re-revision risk. In 2-stage revisions, no difference in overall re-revision rates between designs was observed. This might indicate that the differences observed for 1-stage procedures are due to differences between the patient cohorts, not reflected by the parameters available or surgeon choice

Aims. The risk of mechanical failure of modular revision hip stems is frequently mentioned in the literature, but little is currently known about the actual clinical failure rates of this type of prosthesis. The current retrospective long-term analysis examines the distal and modular failure patterns of the Prevision hip stem from 18 years of clinical use. A design improvement of the modular taper was introduced in 2008, and the data could also be used to compare the original and the current design of the modular connection. Methods. We performed an analysis of the Prevision modular hip stem using the manufacturer’s vigilance database and investigated different mechanical failure patterns of the hip stem from January 2004 to December 2022. Results. Two mechanical failure patterns were identified: fractures in the area of the distal fluted profile (distal stem fracture) and failure of the modular taper (modular fracture). A failure rate of 0.07% was observed for distal stem fracture, and modular fracture rates of 1.74% for the original and 0.013% for the current taper design. Conclusion. A low risk of mechanical failure for both fracture types was observed compared to other known complications in revision hip arthroplasty. In addition, the data show that a design change did significantly reduce the risk of a modular fracture. Cite this article: Bone Joint J 2024;106-B(2):151–157

A: - determine the incidence of intraoperative periprosthetic femoral fracture (PFF). B: - determine the incidence of, and the reoperation rate for postoperative PFF. When using either CC or PTS femoral components. Retrospective review of a consecutive series of 11,018 THAs over a ten-year period. All PFFs were identified using regional radiograph archiving and electronic care systems. Of the 11,018 THAs 4,952 were CC and 6,066 were PTS. Between groups, age, sex, and BMI did not differ. A: - 55 (0.5%) had an intraoperative PFF. 44 CC and 11 PTS (p<0.001). 3 patients in each group had a femoral shaft fracture, remaining fractures were either the calcar (20 CC and 2 group) or the greater trochanter (11 CC and 6 PTS). B: - 91(0.8%) sustained a postoperative PFF. Of those 15 were managed conservatively, 15 were revised and 61 (80.3%) had an ORIF. The CC group had both a lower overall rate of postoperative PFFs (0.7% (36/4,952) vs 0.9% (55/6,066); p = 0.341), and a lower rate of return to theatre (0.4% (22/4,952) vs 0.9% (54/6,066); p = 0.005). 1.3% of male PTS (36/2,674) had a reoperation compared to 0.3% of male CC (7/2,121) (p<0.001). With regard to stem fracture there were none in the Corail group and 5 in the Exeter group. Of these 2 were sub trunnion and 3 were basal neck. A: - There were significantly more intraoperative PFFs with CC 44 (0.8%) than PTS 11 (0.2%). However, the majority of fractures were either of the calcar or greater trochanter with no impact on early recovery or one year Oxford scores. B: - Male PTS were five times more likely to have a reoperation for postoperative PFF. Females had the same incidence of reoperation with either component type. There were 5 stem fractures in the Exeter group and none in the Corail. These results represent robust estimates, which are likely to be more accurate than revision only studies typically generated from registry data

Aims. United Classification System (UCS) B2 and B3 periprosthetic fractures in total hip arthroplasties (THAs) have been commonly managed with modular tapered stems. No study has evaluated the use of monoblock fluted tapered titanium stems for this indication. This study aimed to evaluate the effects of a monoblock stems on implant survivorship, postoperative outcomes, radiological outcomes, and osseointegration following treatment of THA UCS B2 and B3 periprosthetic fractures. Methods. A retrospective review was conducted of all patients who underwent revision THA (rTHA) for periprosthetic UCS B2 and B3 periprosthetic fracture who received a single design monoblock fluted tapered titanium stem at two large, tertiary care, academic hospitals. A total of 72 patients met inclusion and exclusion criteria (68 UCS B2, and four UCS B3 fractures). Primary outcomes of interest were radiological stem subsidence (> 5 mm), radiological osseointegration, and fracture union. Sub-analysis was also done for 46 patients with minimum one-year follow-up. Results. For the total cohort, stem osseointegration, fracture union, and stem subsidence were 98.6%, 98.6%, and 6.9%, respectively, at latest follow-up (mean follow-up 27.0 months (SD 22.4)). For patients with minimum one-year of follow-up, stem osseointegration, fracture union, and stem subsidence were 97.8%, 97.8%, and 6.5%, respectively. Conclusion. Monoblock fluted stems can be an acceptable modality for the management of UCS B2 periprosthetic fractures in rTHAs due to high rates of stem osseointegration and survival, and the low rates of stem subsidence, and revision. Further research on the use of this stem for UCS B3 periprosthetic fractures is warranted to determine if the same conclusion can be made for this fracture pattern. Cite this article: Bone Jt Open 2023;4(8):551–558

We had previously reported on early outcomes on a new fluted, titanium, monobloc stem with a three degree taper that has been designed for challenging femoral reconstruction in the setting of extensive bone loss. The aim of this study was to report its mid-term clinical and radiographic outcomes. This is a retrospective review of prospectively collected data carried out at a single institution between Jan 2017 and Dec 2019. 85 femoral revisions were performed using a new tapered, fluted, titanium, monobloc (TFTM) revision stem. Complications, clinical and radiographic data were obtained from medical records and a locally maintained database. Clinical outcomes were assessed using the Oxford Hip Score (OHS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). All post-operative radiographs were analysed for subsidence, osteolysis and femoral cortical bone remodelling. Mean follow-up was 60 months (range 28–84 months). Subsidence of 1.2 mm was noted in one patient. No cases of clinically significant subsidence (10 mm) were observed. At final follow-up, a statistically significant improvement was noted in functional outcome scores. The mean OHS preoperatively and at final follow-up were 24 (SD 13) and 42 (SD15). p = 0.04 mean difference 18 (95% CI 15–22). The mean WOMAC scores preoperatively and at final follow-up were 62 (SD23) and 88 (SD7) respectively (p < 0.001, mean difference 26; 95% CI 21–34). No stem fractures were noted within the follow-up period. Two patients had revision of the stem's one for infection and another for persistent pain. Positive mid-term clinical and radiological outcomes have been observed with this tapered, fluted, titanium, monobloc stem. Based on these results, this implant may be considered as a viable option in the majority of uncemented femoral revisions

Although data on uncemented short stems are available, studies on cemented short-stemmed THAs are limited. These cemented short stems may have inferior long-term outcomes and higher femoral component fracture rates. Hence, we examined the long-term follow-up of cemented short Exeter stems used in primary THA. Within the Exeter stem range, 7 stems have a stem length of 125 mm or less. These stems are often used in small patients, in young patients with a narrow femoral canal or patients with anatomical abnormalities. Based on our local database, we included 394 consecutive cemented stems used in primary THA (n=333 patients) with a stem length ≤125 mm implanted in our tertiary referral center between 1993 and December 2021. We used the Dutch Arthroplasty Registry (LROI) to complete and cross-check the data. Kaplan-Meier survival analyses were performed to determine 20-year survival rates with stem revision for any reason, for septic loosening, for aseptic loosening and for femoral component fracture as endpoints. The proportion of male patients was 21% (n=83). Median age at surgery was 42 years (interquartile range: 30–55). The main indication for primary THA was childhood hip diseases (51%). The 20-year stem survival rate of the short stem was 85.4% (95% CI: 73.9–92.0) for revision for any reason and 96.2% (95%CI: 90.5–98.5) for revision for septic loosening. No stems were revised for aseptic femoral loosening. However, there were 4 stem fractures at 6.6, 11.6, 16.5 and 18.2 years of follow-up. The stem survival with femoral component fracture as endpoint was 92.7% (CI: 78.5–97.6) at 20 years. Cemented short Exeter stems in primary THA show acceptable survival rates at long-term follow-up. Although femoral component fracture is a rare complication of a cemented short Exeter stem, orthopaedic surgeons should be aware of its incidence and possible risk factors

Angular proximal femoral deformities increase the technical complexity of primary total hip arthroplasties (THAs). The goals were to determine the long-term implant survivorship, risk factors, complications, and clinical outcomes of contemporary primary THAs in this difficult cohort. Our institutional total joint registry was used to identify 119 primary THAs performed in 109 patients with an angular proximal femoral deformity between 1997 and 2017. The deformity was related to previous femoral osteotomy in 85%, and developmental or metabolic disorders in 15%. 53% had a predominantly varus angular deformity. The mean age was 44 years, mean BMI was 29 kg/m. 2. , and 59% were female. An uncemented metaphyseal fixation stem was used in 30%, an uncemented diaphyseal fixation stem in 28%, an uncemented modular body stem with metaphyseal fixation sleeve in 24%, and a cemented stem in 18%. Simultaneous corrective femoral osteotomy was performed in 18%. Kaplan-Meier survivorships and Harris hip scores were reported. Mean follow-up was 8 years. The 10-year survivorships free of femoral loosening, aseptic femoral revision, any revision, and any reoperation were 95%, 93%, 90% and 88%, respectively. Revisions occurred in 13 hips for: aseptic femoral component loosening (3), stem fracture (2), dislocation (2), aseptic acetabular loosening (2), polyethylene liner exchange (2), and infection (2). Preoperative varus angular deformities were associated with a higher risk of any revision (HR 10, p=0.03), and simultaneous osteotomies with a higher risk of any reoperation (HR 3.6, p=0.02). Mean Harris hip scores improved from 52 preoperatively to 82 at 10 years (p<0.001). In the largest series to date of primary THAs in patients with angular proximal femoral deformities, we found a good 10-year survivorship free from any revision. Varus angular deformities, particularly those treated with a simultaneous osteotomy due to the magnitude or location of the deformity, had a higher reoperation rate. Keywords: Proximal femoral deformity; dysplasia; femoral osteotomy; survivorship; revision. Level of evidence: Level III, comparative retrospective cohort

Arthroplasty has consistently shown ‘beneficial and often dramatic improvements in quality of life'. In developed healthcare systems arthroplasty has evolved to minimised complications through evidence-based implant selection, rigorous infection control and high volume training. The Children's Surgical Centre has performed 256 THAs since 2007, We aim to assess the outcome of arthroplasty in a LMIC. Our primary outcome was all cause of re-operation and our secondary outcome was any complications not requiring return to theatre. A retrospective review of all consecutive THA since 2007 was conducted. Electronic and physical case notes were reviewed and basic demographics, indication for THA, risk factors for complications, implant combinations and complications were recorded. Statistical analysis was performed using MedCalc. A total of 256 THA were identified in 225 patients. The mean age was 43, with a M2:1F ratio. The most common pathologies were (1)AVN (44%), (2)OA (11%) and (3)DDH (11%). Revision rate was 13%. The mean time from implantation to revision was 2.8 years (0–9). The most common reasons for revision were (1)stem fracture (5.8%), (2)aseptic loosening (4.8%) and (3)infection (2.7%). Six different stems have been use over the time period. The best surviving were the Zimmer ML Taper and the UMA Muller stems. The UMA C-Stem was the worst performing which suffered 100% stem fracture. 109 complications were identified in 85 patients (33.2%). The three most common complications were (1)aseptic loosening (10.5%) (2)stem fracture (5.8%) and (3)dislocation (5.8%). Previous surgery (n=44) was found to be a significant risk for complications but not infection. OHS initially improved but began to decline after year 3. Patients present to CSC with neglected hip pathology, disability and significant pre-operative deformity. These patients benefit from THA and the initially high complication rates at CSC are declining suggesting the apex of the ‘learning curve' has passed. Cheap poorly manufactured implants continue to cause catastrophic failure

Introduction and Objective. Curative resection of proximal humerus tumours is now possible in this era of limb salvage with endoprosthetic replacement considered as the preferred reconstructive option. However, it has also been linked with mechanical and non-mechanical failures such as stem fracture and aseptic loosening. One of the challenges is to ensure that implants will endure the mechanical strain under physiological loading conditions, especially crucial in long surviving patients. The objective is to investigate the effect of varying prosthesis length on the bone and implant stresses in a reconstructed humerus-prosthesis assembly after tumour resection using finite element (FE) modelling. Methods. Computed tomography (CT) scans of 10 humeri were processed in Mimics 17 to create three-dimensional (3D) cortical and cancellous solid bone models. Endoprostheses of different lengths manufactured by Stryker were modelled using Solidworks 2020. The FE models were divided into four groups namely group A consisting of the intact humerus and groups B, C and D composed of humerus-prosthesis assemblies with a body length of 40, 100 and 120 mm respectively and were meshed using linear 4-noded tetrahedral elements in 3matic 13. The models were then imported into Abaqus CAE 6.14. Isotropic linear elastic behaviour with an elastic modulus of 13400, 2000 and 208 000 MPa were assigned to the cortical bone, cancellous bone and prosthesis respectively and a Poisson's ratio of 0.3 was assumed for each material. To represent the lifting of heavy objects and twisting motion, a tensile load of 200 N for axial loading and a 5 Nm torsional load for torsional loading was applied separately to the elbow joint surface with the glenohumeral joint fixed and with all contact interfaces defined as fully bonded. A comparative analysis against literature was performed to validate the intact model. Statistical analysis of the peak von Mises stress values collected from predicted stress contour plots was performed using a one-way repeated measure of analysis of variance (with a Bonferroni post hoc test) using SPSS Statistics 26. The average change in stress of the resected models from the intact state were then determined. Results. The validation of the intact humerus displayed a good agreement with literature values. The peak bone stress occurred distally above the coronoid and olecranon fossa closer to the load application region in the intact and resected bone models with a significant amount of loading borne by the cortical bone, while the peak implant stress occurred at the bone-prosthesis contact interface under both loading conditions. Based on the results obtained, a statistically significant difference (p =.013) in implant stress was only seen to occur between groups B and C under tension. Results illustrate initiation of stress shielding with the bone bearing lesser stress with increasing resection length which may eventually lead to implant failure by causing bone resorption according to Wolff's law. The peak implant stress under torsion was 3–5 times the stress under tension. The best biomechanical behaviour was exhibited in Group D, having the least average change in stress from the intact model, 5% and 3.8% under tension and torsion respectively. It can be deduced that the shorter the prosthesis length, the more pronounced the effect on cortical bone remodelling. With the maximum bone and implant stresses obtained being less than their yield strength, it can be concluded that the bone-implant construct is safe from failure. Conclusions. The developed FE models verified the influence of varying the prosthesis length on the bone and implant stresses and predicted signs of stress shielding in longer endoprostheses. By allowing for 2 cm shortening in the upper extremity and post-surgical scarring, it is beneficial to err towards a shorter endoprosthesis

Cement-in-cement femoral revision is a proven technique in revision total hip arthroplasty, with excellent results when using standard sized Exeter stems. The Exeter 44/00 125 mm short revision stem was introduced in 2004 to facilitate cement-in-cement revision. The stem is 25mm shorter and has a slimmer body to allow greater flexibility to adjust depth of insertion and version of the stem. However, it is not known if this change in stem length and size effects its longer term performance. We therefore reviewed the clinical outcome and survival of the Exeter 44/00 short stem used for cement-in-cement revision in our unit, with a minimum of 5 years follow up. 166 cases were performed between 2004 and 2010. 103 hips were available for 5 year clinical and radiological follow up, with 91 hips surviving to final review in 2017. At 5 years, 43 hips had died, 13 were revised and 7 were too frail to attend clinical review. The fate of all 166 hips were known and included in the survival analysis. Median clinical scores improved significantly. Sixteen hips required re-revision (infection 6, loose cup 3, periprosthetic fracture 3, instability 2, stem fracture with chronic infection 1 and pain 1). Kaplan-meier survival analysis revealed 100% survival for aseptic loosening, 96.8% survival for stem failure and 88.9% survival for all causes. This is the largest series with the longest follow up of the Exeter 44/00 short revision stem. The stem performs equally well as standard Exeter stems with regards to aseptic loosening. The single stem fracture occurred secondary to bone loss in chronic infection, highlighting the importance of providing adequate proximal support for the stem. Periprosthetic fracture occurred in 2.4% of this series of revision cases. Larger registry-based studies may provide additional information on the performance of this stem

Background. Since 1991 to 2008 approximately 800,000 Exeter stems have been sold worldwide with 80 reported cases of fracture (neck or stem). This study aimed to determine factors predisposing to fracture. Method. Clinical, surgical, radiological and retrieval data was collated from Stryker Benoist-Girard and Exeter research databases. Risk factors associated with fracture were categorised to patient related (weight and activity levels), surgical related (poor medial support, component size, placement) and implant related (+ head). Results. Data was available on 60 patients (28 stem, 32 neck fractures). Number of fractures per annum increased in proportion with sales. Mean patient age at fracture was similar for both neck and stem fractures (69yrs, 53–84; 67yrs, 30–89. p=0.56). 77% neck and 52% stem fractures occurred in males. Mean weight was 110kg (82–140) in neck and 91kg (70–126) in stem fractures with 68% neck and 38% stem fractures either obese or morbidly obese. Mean time to fracture was 78mths (36–144) for neck and 76 mths (2–155) for stem fractures. 76% of neck fractures occurred in stem sizes 44#2, 44#3 and 44¢4. Stem fractures occurred more commonly (85%) in the smaller sizes (35.5 to 44#1). A + head was used in 67% neck and 14% of stem fractures. Neck fractures were most commonly associated with patient (increased weight and activity) and implant related (use of a + head) factors. Stem fractures were most commonly associated with correctable surgical related causes predominantly secondary to stem undersizing or inadequate medial support. Conclusion. Careful pre operative planning and templating is essential to identify those patients with pre-existing identifiable patient (weight, activity levels) and anatomical (proximal femoral canal morphology and offset) risk factors, to ensure appropriate stem selection and size (which may require a custom made implant) and meticulous placement and cementing technique in order to maximise fracture prevention

Introduction and Objective. Some periprosthetic femoral fractures (PFFs) present history and radiographic aspect consistent with an atypical femoral fracture (AFF), fulfilling the criteria for AFF except that PFFs by themselves are excluded from the diagnosis of AFFs. The aim of this study was to evaluate in a single Institution series of PFFs if any of them could be considered a periprosthetic atypical femoral fracture (PAFF), and their prevalence. Materials and Methods. Surgical records were searched for PFFs around a primary hip stem from January 2013 to December 2019. Cases were classified according to Vancouver classification. Demographic and medical history were extracted. Fisher's exact test was used for statistical analysis. Results. One-hundred-fifteen PFFs were identified, 59 of them were type B1 and 16 were type C. Radiographs and medical records were available for all patients. Twenty-four patients (32%) have been treated with bisphosphonates (BPs) for longer than 4 years. Four patients presented a fracture with characteristics of PAFF. When enlarged to all PFFs of the series, no other PAFF was found: prevalence of PAFFs was 5.3% for type B1 and C cases and 3.5% for all surgically treated PFFs. Statistical significative difference between PAFFs and PFFs was found for prolonged BPs assumption and for the level of fracture clear of the stem. Conclusions. Fracture with characteristics of AFFs can also happen over a prosthetic stem, configuring themselves as PAFFs, and they are related to prolonged BPs use. As a correct diagnosis is mandatory for proper treatment, a revision of criteria for AFFs should be considered, accepting that PAFFs exist

Fully constrained liners are used to treat recurrent dislocations or patients at high risk after total hip replacements. However, they can cause significant morbidities including recurrent dislocations, infections, aseptic loosening and fractures. We examine long term results of 111 patients with tripolar constrained components to assess their redislocation and failure rate. The purpose of this study was to assess survivorship, complications and functional outcomes at a minimum 10 years after the constrained tripolar liners used in our institute. We retrospectively identified 111 patients who had 113 revision tripolar constrained liners between 1998 and 2008. Eighty-nine were revised due to recurrent dislocations, 11 for pseudotumor with dysfunctional abductors, and 13 for periprosthetic infection with loss of soft tissue stabilizers. All patients had revision hip arthroplasty before the constrained liner was used: 13 after the first revision, 17 after the second, 38 after the third, and 45 had more than 3 revisions. We extracted demographics, implant data, rate of dislocations and incidence of other complications. Kaplan Meier curves were used to assess dislocation and failure for any reason. WOMAC was used to assess quality of life. At 10 years, the survival free of dislocation was 95.6% (95%CI 90- 98), and at 20 years to 90.6% (95% CI 81- 95.5). Eight patients (7.1%) had dislocations of their constrained liners: 1 patient had simultaneous periprosthetic infection identified at the time of open reduction, and 1 patient sustained stem fracture 3 months prior to the liner dislocation. At 10 years, the survival to any further surgery was 89.4% (95% CI 82–93.8), and at 20 years, this was 82.5 (95% CI 71.9–89.3). Five patients (4.4%) had deep infection: 4 of these had excision arthroplasty due to failure to control infection, while 1 patient was treated successfully with debridement, exchange of mobile components and intravenous antibiotics. Two patients (1.8%) had dissociated rings that required change of liner, ring and head. Two patients (1.8%) had periprosthetic femoral fractures that were treated by revision stems and exchange of constrained liners. The mean WOMAC functional and pain scores were 66.2 and 75.9 of 100, respectively. Constrained tripolar liners in our institute provided favourable results in the long term for recurrent dislocation hip arthroplasty with dysfunctional hip stabilizers. Infection in these patients can prove to be difficult to treat due to their poor soft tissue conditions from repeated surgeries. Comparing long terms results from other types of constrained liners is essential to evaluate these salvage liners

Aims

The Exeter V40 femoral stem is the most implanted stem in the National Joint Registry (NJR) for primary total hip arthroplasty (THA). In 2004, the 44/00/125 stem was released for use in ‘cement-in-cement’ revision cases. It has, however, been used ‘off-label’ as a primary stem when patient anatomy requires a smaller stem with a 44 mm offset. We aimed to investigate survival of this implant in comparison to others in the range when used in primary THAs recorded in the NJR.

Aims

Surgical limb sparing for knee-bearing paediatric bone sarcoma is considered to have a clinically significant influence on postoperative function due to complications and leg-length discrepancies. However, researchers have not fully evaluated the long-term postoperative functional outcomes. Therefore, in this study, we aimed to elucidate the risk factors and long-term functional prognosis associated with paediatric limb-sparing surgery.

Femoral stem fracture occurred in five (2%) of 283 revision hip arthroplasties when extensively coated, distal fixation femoral implants were used. Common features were complex revisions, high body mass index, poor proximal support, smaller stems (< 13.5 mm) and use of an extended trochanteric osteotomy. Use of strut allografts can reduce femoral stem stresses. The purpose of this study was to analyze the surgical factors associated with fracture of cementless distal fixation revision femoral stems and supplement this analysis with a finite element analysis. Data from our institutional joint replacement database identified five (2%) fractured femoral stems (three Solution, two Echelon) in a cohort of two hundred and eighty-three cementless distal fixation femoral stems (one hundred and eighty-two Solution, one hundred and one Echelon) followed over two years. Patient, surgical and implant factors were compared between the fractured and not fractured stems. Finite element analysis was performed on two fractured stem cases to better understand the fracture mechanism. Common clinical features of the five fractured stems were complex revisions, high patient body mass index, poor proximal bone support, smaller stems (< 13.5 mm) and use of an extended trochanteric osteotomy (ETO) (3/5). Fatigue failure was the mode failure in all cases. Finite element analysis confirmed that the location of highest stem stress was near the location of the stem fracture and that use of a strut graft over an extended trochanteric osteotomy in patients lacking proximal femoral cortical support decreased the stem stresses by 48%. Use of cementless distal fixation revision femoral stems is accompanied by a 2% risk of stem fracture in the face of proximal femoral support of the stem and/or use of a stem with a diameter less than 13.5 mm. When an extended trochanteric osteotomy is used, the stem fracture rate increased to 4%. Use of a strut allograft in conjunction with the ETO can reduce stem stresses by 48% and the risk of stem fracture. Funding: Research support from J& J DePuy and Smith & Nephew