Revision of metal-on-metal hip replacements with dual-mobility bearings and acetabular component retention.

Aims: In metal-on-metal (MoM) hip arthroplasties and resurfacings, mechanically induced corrosion can lead to elevated serum metal ions, a local inflammatory response, and formation of pseudotumours, ultimately requiring revision. The size and diametral clearance of anatomical (ADM) and modular (MDM) dual-mobility polyethylene bearings match those of Birmingham hip MoM components. If the acetabular component is satisfactorily positioned, well integrated into the bone, and has no surface damage, this presents the opportunity for revision with exchange of the metal head for ADM/MDM polyethylene bearings without removal of the acetabular component. Methods: Between 2012 and 2020, across two centres, 94 patients underwent revision of Birmingham MoM hip arthroplasties or resurfacings. Mean age was 65.5 years (33 to 87). In 53 patients (56.4%), the acetabular component was retained and dual-mobility bearings were used (DM); in 41 (43.6%) the acetabulum was revised (AR). Patients underwent follow-up of minimum two-years (mean 4.6 (2.1 to 8.5) years). Results: In the DM group, two (3.8%) patients underwent further surgery: one (1.9%) for dislocation and one (1.9%) for infection. In the AR group, four (9.8%) underwent further procedures: two (4.9%) for loosening of the acetabular component and two (4.9%) following dislocations. There were no other dislocations in either group. In the DM group, operating time (68.4 vs 101.5 mins, p < 0.001), postoperative drop in haemoglobin (16.6 vs 27.8 g/L, p < 0.001), and length of stay (1.8 vs 2.4 days, p < 0.001) were significantly lower. There was a significant reduction in serum metal ions postoperatively in both groups (p < 0.001), although there was no difference between groups for this reduction (p = 0.674 (cobalt); p = 0.186 (chromium)). Conclusion: In selected patients with Birmingham MoM hips, where the acetabular component is well-fixed and in a satisfactory position with no surface damage, the metal head can be exchanged for polyethylene ADM/MDM bearings with retention of the acetabular prosthesis. This presents significant benefits, with a shorter procedure and a lower risk of complications.

Intraoperative cell salvage in revision hip arthroplasty.

Aims: The aim of this study was to perform a systematic review of the evidence for the use of intraoperative cell salvage in patients undergoing revision hip arthroplasty, and specifically to analyze the available data in order to quantify any associated reduction in the use of allogenic blood transfusion, and the volume which is used. Methods: An electronic search of MEDLINE (PubMed), Embase, Scopus, and the Cochrane Library was completed from the date of their inception to 24 February 2022, using a search strategy and protocol created in conjunction with the PRISMA statement. Inclusion criteria were patients aged > 18 years who underwent revision hip arthroplasty when cell salvage was used. Studies in which pre-donated red blood cells were used were excluded. A meta-analysis was also performed using a random effects model with significance set at p = 0.05. Results: Of the 283 studies which were identified, 11 were included in the systematic review, and nine in the meta-analysis. There was a significant difference (p < 0.001) in the proportion of patients requiring allogenic transfusion between groups, with an odds ratio of 0.331 (95% confidence interval (CI) 0.165 to 0.663) associated with the use of cell salvage. For a total of 561 patients undergoing revision hip arthroplasty who were treated with cell salvage, 247 (44.0%) required allogenic transfusion compared with 418 of 643 patients (65.0%) who were treated without cell salvage. For those treated with cell salvage, the mean volume of allogenic blood which was required was 1.95 units (390 ml) per patient (0.7 to 4.5 units), compared with 3.25 units (650 ml) per patient (1.2 to 7.0 units) in those treated without cell salvage. The mean difference of -1.91 units (95% CI -4.0 to 0.2) in the meta-analysis was also significant (p = 0.003). Conclusion: We found a a significant reduction in the need for allogenic blood transfusion when cell salvage was used in patients undergoing revision hip arthroplasty, supporting its routine use in these patients. Further research is required to determine whether this effect is associated with types of revision arthroplasty of differing complexity.

Survival of the Exeter V40 short revision (44/00/125) stem when used in primary total hip arthroplasty.

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. We analyzed 328,737 primary THAs using the Exeter V40 stem, comprising 34.3% of the 958,869 from the start of the NJR to December 2018. Our exposure was the stem, and the outcome was all-cause construct revision. We stratified analyses into four groups: constructs using the 44/00/125 stem, those using the 44/0/150 stem, those including a 35.5/125 stem, and constructs using any other Exeter V40 stem. In all 328,737 THAs using an Exeter V40 stem, the revision estimate was 2.8% (95% confidence interval (CI) 2.7 to 2.8). The 44/00/125 stem was implanted in 2,158 primary THAs, and the ten-year revision estimate was 4.9% (95% CI 3.6 to 6.8). Controlling for age, sex, year of operation, indication, and American Society of Anesthesiologists grade demonstrated an increased overall hazard of revision for constructs using the 44/00/125 stem compared to constructs using other Exeter V40 femoral stems (hazard ratio 1.8 (95% CI 1.4 to 2.3)). Although the revision estimate is within the National Institute for Health and Care Excellence ten-year benchmark, survivorship of constructs using the 44/00/125 stem appears to be lower than the rest of the range. Adjusted analyses will not take into account 'confounding by indication', e.g. patients with complex anatomy who may have a higher risk of revision. Surgeons and patients should be reassured but be aware of the observed increased revision estimate, and only use this stem when other implants are not suitable.

Cemented Femoral Stem Fixation: Back to the Future.

BACKGROUND: Periprosthetic fractures following elective and nonelective hip arthroplasty remain one of the most common modes of early failure. METHODS: This symposium will explore the current role of cemented fixation and periprosthetic fracture, focusing on history and rationale for cemented stem fixation, registry data, and other potential advantages of cemented stem fixation. A meticulous and methodical surgical technique of cemented stem fixation is paramount to the success and will be thoroughly discussed. RESULTS: The role of stem fixation, and its effect on periprosthetic fracture is well-documented in the literature. Yet despite this, the utilization of cemented stem fixation remains low in the United States. This paradox is multifactorial. CONCLUSION: In addition to a notable reduction in the risk of periprosthetic femur fractures, cemented stem fixation has numerous other advantages and is reproducible with a methodical surgical technique.

A Rare Case of Open 3A VTB2W Periprosthetic Fracture around a Total Hip Arthroplasty.

Introduction: The incidence of periprosthetic fracture (PPF) around a total hip arthroplasty (THA) continues to increase with the rise of number of THA performed. We present a rare case of a 73-year-old man who sustained an open periprosthetic femur fracture around a THA. Case Report: This gentleman sustained an open PPF around a fully cemented THA after he lost control and fell off his bicycle. After thorough surgical debridement, internal fixation with double plating was performed and the fracture went on to unite with an excellent patient reported outcome score. To the best of our knowledge, this is the only reported open 3A VTB2W PPF THA in the literature. Conclusion: Open PPF around a THA is a rare and uncommon occurrence. Principles of open fracture management should be continued and we recommend urgent surgery to reduce the risk of post-operative infection. Open VTB2W PPF should be fixed with double plating if the bone cement interface is intact and the fracture can be anatomically reduced. Double plating gives additional rotational stability and allows early weight bearing post-operatively.

Is rationing of total hip arthroplasty justified? Working to optimize patient accessibility to surgery using long-term patient-reported outcome data.

AIMS: The aim of this study was to assess medium-term improvements following total hip arthroplasty (THA), and to evaluate what effect different preoperative Oxford Hip Score (OHS) thresholds for treatment may have on patients' access to THA and outcomes. METHODS: Patients undergoing primary THA at our institution with an OHS both preoperatively and at least four years postoperatively were included. Rationing thresholds were explored to identify possible deprivation of OHS improvement. RESULTS: Overall, 2,341 patients were included. Mean OHS was 19.7 (SD 8.2) preoperatively and 39.7 (SD 9.8) at latest follow-up. An improvement of at least eight-points, the minimally important change (MIC), was seen in 2,072 patients (88.5%). The mean improvement was 20.0 points (SD 10.5). If a rationing threshold of OHS of 20 points had been enforced, 90.8% of those treated would have achieved the MIC, but only 54.3% of our cohort would have had access to surgery; increasing this threshold to 32 would have enabled 89.5% of those treated to achieve the MIC while only depriving 6.5% of our cohort. The 'rationed' group of OHS > 20 had significantly better OHS at latest follow-up (42.6 vs 37.3; p < 0.001), while extending the rationing threshold above 32 showed postoperative scores were more significantly affected by the ceiling effect of the OHS. CONCLUSION: The OHS was not designed as a tool to ration healthcare, but if it had been used at our institution for this cohort, applying an OHS threshold of 20 to routine THA access would have excluded nearly half of patients from having a THA; a group in which over 85% had a significant improvement in OHS. Where its use for rationing is deemed necessary, use of a higher threshold may be more appropriate to ensure a better balance between patient access to treatment and chances of achieving good to excellent outcomes. Cite this article: Bone Jt Open 2022;3(3):196-204.

B2 or not B2? That is the question: a review of periprosthetic fractures around cemented taper-slip femoral components.

AIMS: Periprosthetic fractures (PPFs) around cemented taper-slip femoral prostheses often result in a femoral component that is loose at the prosthesis-cement interface, but where the cement-bone interface remains well-fixed and bone stock is good. We aim to understand how best to classify and manage these fractures by using a modification of the Vancouver classification. METHODS: We reviewed 87 PPFs. Each was a first episode of fracture around a cemented femoral component, where surgical management consisted of revision surgery. Data regarding initial injury, intraoperative findings, and management were prospectively collected. Patient records and serial radiographs were reviewed to determine fracture classification, whether the bone cement was well fixed (B2W) or loose (B2L), and time to fracture union following treatment. RESULTS: In total, 47 B2W fractures (54.0%) and one B3 fracture (1.1%) had cement that remained well-fixed at the cement-bone interface. These cases were treated with cement-in-cement (CinC) revision arthroplasty. Overall, 43 fractures with follow-up united, and two patients sustained further fractures secondary to nonunion and required further revision surgery. A total of 19 B2L fractures (21.8%) and 19 B3 fractures (21.8%) had cement that was loose at the cement-bone interface. These cases were managed by revision arthroplasty with either cemented or uncemented femoral components, or proximal femoral arthroplasty. One case could not be classified. CONCLUSION: We endorse a modification of the original Vancouver system to include a subclassification of B2 fractures around cemented femoral prostheses to include B2W (where cement is well-fixed to bone) and B2L (where the cement is loose). Fractures around taper-slip design stems are more likely to fracture in a B2W pattern compared to fractures around composite beam design stems which are more likely to fracture in a B2L pattern. B2W fractures can reliably be managed with CinC revision. Cite this article: Bone Joint J 2021;103-B(1):71-78.

Long-Term Survival of the Cemented Exeter Universal Stem in Patients 50 Years and Younger: An Update on 130 Hips.

BACKGROUND: There is variable evidence regarding survivorship beyond 20 years of total hip arthroplasties in young patients. We report the long-term results of the Exeter cemented hip system in patients ≤50 years at minimum of 20 years. METHODS: Clinical and radiological outcomes of 130 consecutive total hip arthroplasties in 107 patients aged 50 years or younger at primary operation were reviewed; 77% had a diagnosis other than osteoarthritis. All patients were followed at 5-year intervals, no patients were lost to follow-up, and the status of every implant is known. RESULTS: Mean age at surgery was 41.8 (17-50) years. Mean follow-up was 22.0 (20.0-26.1) years. There were 79 hips surviving, 14 hips (11 patients) deceased, and 37 hips revised. Reasons for revision: 29 hips for aseptic cup loosening (26 stems revised using cement-in-cement, three left in-situ); three stems for femoral osteolysis, two related to acetabular polyethylene wear (14.1 and 17.0 years), one with Gaucher's disease (21.1 years); one broken stem (12.9 years); one cup for instability (4.3 years-stem revised using cement-in-cement); and two hips with infection (8.5 and 23.8 years). There were no cases of aseptic loosening of the Exeter stem. There were no radiologically loose stems although eight patients had radiological evidence of loosening of the cemented cup. Survivorship at 22 years was 74.9% for revision for all causes and 96.3% for revision of the stem for aseptic loosening or lysis. CONCLUSION: The Exeter cemented stem has excellent survivorship at minimum 20 years in young patients. Acetabular component survivorship was less favorable, but the advent of highly cross-linked polyethylene may improve this in the long term.

An Analysis of Reported Cases of Fracture of the Universal Exeter Femoral Stem Prosthesis.

BACKGROUND: Between 1991 and 2008, approximately 80 cases of fracture (neck or stem) have been reported. This study aimed at determining factors predisposing to implant fracture. METHODS: Clinical, surgical, radiological, and retrieval data were collated. Risk factors associated with fracture were categorized to patient related (weight and activity levels), surgical related (poor medial support, component size, and placement), and anatomic/implant related (head size/offset). RESULTS: Data was available on 60 patients (32 stem and 28 neck fractures). Mean patient age at fracture was similar for both neck and stem fractures (69 years, 67 years, respectively). Also, 77% neck and 52% stem fractures occurred in men. Mean weight was 107 kg in neck and 96.5 kg in stem fractures with 68% neck and 38% stem fractures either obese or morbidly obese. Mean time to fracture was 78 months (range, 36-144 months) for neck and 76 months (range, 2-155 months) for stem fractures. 44#2 and 44#3 were the most common sizes associated with neck fractures. Stem fractures occurred more commonly (84%) in the smaller sizes (35.5 to 44#1). Elongated femoral heads were used in 69% neck and 14% stem fractures. CONCLUSION: Neck fractures were most commonly associated with patient-related (increased weight and activity) and implant-related (use of an elongated femoral head) factors. Stem fractures were most commonly associated with correctable surgical-related causes, predominantly secondary to stem undersizing or inadequate medial support (84%).

Short-term results with a constrained acetabular liner in patients at high risk of dislocation after primary total hip arthroplasty.

BACKGROUND: Dislocation following primary total hip arthroplasty (THA) is a complication with an incidence of 2%-5%. This study examines the clinical and radiological outcome of a constrained acetabular implant used in primary THA in high-risk patients to prevent dislocation. METHODS: 54 patients with 55 constrained implants for primary THA were reviewed clinically and radiologically. Oxford, Harris Hip and Charlson scores were recorded. RESULTS: 54 patients, with an average age of 83.2 years, were followed up at a mean of 44.9 (20-74) months. 38 had an hydroxyapatite- (HA) coated acetabular shell with a constrained insert and 17 had a cemented constrained implant. The median Charlson score at surgery was 5 (4-10). There were significant improvements in Oxford, Harris hip pain and function scores and Charnley pain after surgery.2 patients had radiolucent lines on the most recent radiograph. Neither was symptomatic and the acetabular components had not migrated.3 patients developed postoperative infection, 1 deep requiring a 2-stage revision.Of the 29 patients who died, 1 required revision 2 months following surgery for dislocation of the constrained liner. This patient died 26 months later from unrelated causes having had no further complications from her surgery. There have been no further revisions or reoperations for dislocation in any of the other cases. CONCLUSIONS: The use of a constrained acetabular liner at primary THA in high risk patients for dislocation can successfully prevent this complication without increasing component loosening. In this series of 55 constrained implants we have a postoperative dislocation rate of 1.8%.

Total hip replacement for hip fracture: Surgical techniques and concepts.

When treating a hip fracture with a total hip replacement (THR) the surgical technique may differ in a number of aspects in comparison to elective arthroplasty. The hip fracture patient is more likely to have poor bone stock secondary to osteoporosis, be older, have a greater number of co-morbidities, and have had limited peri-operative work-up. These factors lead to a higher risk of complications, morbidity and perioperative mortality. Consideration should be made to performing the THR in a laminar flow theatre, by a surgeon experienced in total hip arthroplasty, using an anterolateral approach, cementing the implant in place, using a large head size and with repair of the joint capsule. Combined Ortho-geriatric care is recommended with similar post-operative rehabilitation to elective THR patients but with less expectation of short length of stay and consideration for fracture prevention measures.

The results of acetabular impaction grafting in 129 primary cemented total hip arthroplasties.

Between 1995 and 2003, 129 cemented primary THAs were performed using full acetabular impaction grafting to reconstruct acetabular deficiencies. These were classified as cavitary in 74 and segmental in 55 hips. Eighty-one patients were reviewed at mean 9.1 (6.2-14.3) years post-operatively. There were seven acetabular component revisions due to aseptic loosening, and a further 11 cases that had migrated >5mm or tilted >5° on radiological review - ten of which reported no symptoms. Kaplan-Meier analysis of revisions for aseptic loosening demonstrates 100% survival at nine years for cavitary defects compared to 82.6% for segmental defects. Our results suggest that the medium-term survival of this technique is excellent when used for purely cavitary defects but less predictable when used with large rim meshes in segmental defects.

Cement-in-cement revision for selected Vancouver Type B1 femoral periprosthetic fractures: a biomechanical analysis.

The aim of this study was to perform a biomechanical analysis of the cement-in-cement (c-in-c) technique for fixation of selected Vancouver Type B1 femoral periprosthetic fractures and to assess the degree of cement interposition at the fracture site. Six embalmed cadaveric femora were implanted with a cemented femoral stem. Vancouver Type B1 fractures were created by applying a combined axial and rotational load to failure. The femora were repaired using the c-in-c technique and reloaded to failure. The mean primary fracture torque was 117 Nm (SD 16.6, range 89-133). The mean revision fracture torque was 50 Nm (SD 16.6, range 29-74), which is above the torque previously observed for activities of daily living. Cement interposition at the fracture site was found to be minimal.

Benefits of using modern cementing techniques in the acetabulum: the Rim Cutter.

PURPOSE: To compare radiological records of 90 consecutive patients who underwent cemented total hip arthroplasty (THA) with or without use of the Rim Cutter to prepare the acetabulum. METHODS: The acetabulum of 45 patients was prepared using the Rim Cutter, whereas the device was not used in the other 45 patients. Postoperative radiographs were evaluated using a digital templating system to measure (1) the positions of the operated hips with respect to the normal, contralateral hips (the centre of rotation of the socket, the height of the centre of rotation from the teardrop, and lateralisation of the centre of rotation from the teardrop) and (2) the uniformity and width of the cement mantle in the 3 DeLee Charnley acetabular zones, and the number of radiolucencies in these zones. RESULTS: The study group showed improved radiological parameters and were closer to the anatomic centre of rotation both vertically (1.5 vs. 3.7 mm, p<0.001) and horizontally (1.8 vs. 4.4 mm, p<0.001) and had consistently thicker and more uniform cement mantles (p<0.001). There were 2 radiolucent lines in the control group but none in the study group. CONCLUSION: The Rim Cutter resulted in more accurate placement of the centre of rotation of a cemented prosthetic socket, and produced a thicker, more congruent cement mantle with fewer radiolucent lines.

Scaling digital radiographs for templating in total hip arthroplasty using conventional acetate templates independent of calibration markers.

We describe a scaling method for templating digital radiographs using conventional acetate templates independent of template magnification without the need for a calibration marker. The mean magnification factor for the radiology department was determined (119.8%; range, 117%-123.4%). This fixed magnification factor was used to scale the radiographs by the method described. Thirty-two femoral heads on postoperative total hip arthroplasty radiographs were then measured and compared with the actual size. The mean absolute accuracy was within 0.5% of actual head size (range, 0%-3%) with a mean absolute difference of 0.16 mm (range, 0-1 mm; SD, 0.26 mm). Intraclass correlation coefficient showed excellent reliability for both interobserver and intraobserver measurements with intraclass correlation coefficient scores of 0.993 (95% CI, 0.988-0.996) for interobserver measurements and intraobserver measurements ranging between 0.990 and 0.993 (95% CI, 0.980-0.997).

Early failure of total hip replacements implanted at distant hospitals to reduce waiting lists.

AIM: In the years 1990-1993, in an effort to reduce waiting-list time, a small number of patients were sent from Exeter to hospitals in London to undergo elective total hip replacement. No medium- or long-term follow-up was arranged. Our aim was to audit the outcome of these hip replacements. PATIENTS AND METHODS: Review of the records of the referring medical practices, Regional Health Authority, local orthopaedic hospital and the distant centres at which the surgery was performed identified 31 cases. A total of 27 hip replacements in 24 patients were available for clinical and radiological review. RESULTS: 12 (44%) hips have so far required revision surgery, at a mean of 6.5 years. Of these, three (11%) have been for deep infection. A further three hips (11%) are radiologically loose and are being closely monitored. Two patients (7%) suffered permanent sciatic nerve palsy. CONCLUSIONS: Patients whose surgery was performed locally over a similar time period have a published failure rate of only 4.9%. This difference is highly statistically significant (P < 0.001). The causes for such a difference in outcome were analysed and include surgical technique, implant selection and absence of follow-up. In the light of this evidence, we would like to urge the government to address waiting list problems by investing in the local infrastructure. Expanding those facilities where properly audited and fully accountable surgeons operate must be the way forward.

Bone grafts.

Bone grafts are used in musculoskeletal surgery to restore structural integrity and enhance osteogenic potential. The demand for bone graft for skeletal reconstruction in bone tumor, revision arthroplasty, and trauma surgery, couple with recent advances in understanding and application of the biology of bone transplantation, has resulted in an exponential increase in the number of bone-grafting procedures performed over the last decade. It is estimated that 1.5 million bone-grafting procedures are currently performed worldwide each year, compared to a fraction of that number 20 years ago. Major developments also have resulted in the harvesting, storage, and use of bone grafts and production of graft derivatives, substitutes, and bone-inducing agents.