Cementless, modular, titanium stem in Vancouver B2 and B3 periprosthetic femoral fractures.

INTRODUCTION: The periprosthetic femoral fracture (PFF) is a serious complication after primary total hip arthroplasty. We conducted a retrospective study to determine whether the PRIUS® system presented similar survival to other existing implants for the treatment of Vancouver B2 or B3 PFFs. Bone consolidation rate, functional results and complications were analysed. METHOD: This is a bi-centric retrospective study between 2012 and 2017 including 39 patients with (B2/B3) PFFs treated by senior surgeons using a PRIUS® femoral implant. Implant survival, radiological outcome (fracture healing) and clinical scores (Oxford-OHS, Harris Hip Score-HHS, Postel Merle d'Aubigné-PMA, Devane and Charnley) were analysed. 10 patients had died before data collection and 5 patients were lost to follow-up. A total of 21 patients were able to undergo a clinical and radiological evaluation. The mean follow-up period was 3 years. RESULTS: The 3-year PRIUS® stem survival rate was 88.6% [95% CI, 77.2-100]. The consolidation rate was 81% (17/21). The rate of satisfied or very satisfied patients was 85.6% (18/21). Regarding the Devane score, activity level was maintained in 70.6% of cases (12/17) and decreased in 29.4% of cases (5/17), the Charnley score was stable in 94% of cases (16/17) and decreased in 6% of cases (1/17). The mean Oxford score was 28.8/48 (9.3; 16-48), the mean HHS was 67/100 (16.4; 46-91) and the mean PMA score was 12.6/18 (4.5; 2-18). CONCLUSION: The results in terms of survival rate and bone consolidation are comparable to other literature series. The PRIUS® System can be added to the surgical arsenal in the treatment of (B2/B3) PFF, subject to confirmation of these results in the longer term.

Salvage of Painful Porous Coated Stem Ulnar Head Prosthesis With Semiconstrained Distal Radioulnar Joint Arthroplasty.

PURPOSE: To determine the functional outcome and complications after conversion from a painful and unstable ulnar head prosthesis to a semiconstrained distal radioulnar joint arthroplasty. METHODS: We conducted a retrospective review of 11 ulnar head prostheses in 10 patients with porous coated stems that were revised to semiconstrained prostheses. The median age of the patients was 47 years. The median number of wrist surgeries prior to conversion was 4 (range, 1-9). The median time from the ulnar head implant to the revision surgery was 47 months. Pre- and postoperative pain levels were recorded. Mayo Wrist Scores were calculated. Grip strength, range of motion, and complications and reoperations were recorded. RESULTS: All patients reported moderate or severe pain before surgery, whereas 3 patients reported moderate pain after surgery. The Mayo Wrist Score improved considerably from a median of 50 before surgery to 65 after surgery. The grip strength and forearm pronation-supination showed no change following surgery. The median wrist flexion-extension range improved considerably. Follow-up was a median of 64 (range, 15-132) months after revision surgery. Removal of the ulnar head implant was described as difficult by the surgeons, except in 1 case where the implant was loose. Resection of bone from the distal ulna was often necessary. One patient needed a reoperation requiring prosthesis removal for aseptic loosening of the stem 5 years after revision. There were 2 nondisplaced periprosthetic fractures successfully treated with cast immobilization and 2 additional minor complications, 1 postoperative stitch abscess, and 1 extensor carpi ulnaris tendinitis. CONCLUSIONS: Conversion from an ulnar head implant to a semiconstrained prosthesis provided improved pain scores and function with a low reoperation rate in this patient series. Removal of an ulnar head prosthesis can be technically challenging, but it can be performed leaving enough bone stock for immediate implantation of a semiconstrained implant. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Feasibility of a Shape-Memory-Alloy-Actuator System for Modular Acetabular Cups.

Hip implants have a modular structure which enables patient-specific adaptation but also revision of worn or damaged friction partners without compromising the implant-bone connection. To reduce complications during the extraction of ceramic inlays, this work presents a new approach of a shape-memory-alloy-actuator which enables the loosening of ceramic inlays from acetabular hip cups without ceramic chipping or damaging the metal cup. This technical in vitro study exam-ines two principles of heating currents and hot water for thermal activation of the shape-memory-alloy-actuator to generate a force between the metal cup and the ceramic inlay. Mechanical tests concerning push-in and push-out forces, deformation of the acetabular cup according to international test standards, and force generated by the actuator were generated to prove the feasibility of this new approach to ceramic inlay revision. The required disassembly force for a modular acetabular device achieved an average value of 602 N after static and 713 N after cyclic loading. The actuator can provide a push-out force up to 1951 N. In addition, it is shown that the necessary modifications to the implant modules for the implementation of the shape-memory-actuator-system do not result in any change in the mechanical properties compared to conventional systems.

Outcomes after revision of Advanced Bionics Clarion 1.2 cochlear implants.

INTRODUCTION: Cochlear implant reimplantation (CIR) for external processor upgrade or device failure is becoming increasingly common as the population of cochlear implant recipients ages. Patients with Advanced Bionics (AB) Clarion 1.2 cochlear implants may undergo CIR for device age/failure or desired technology upgrade so that they may use newer external processors that have improved connectivity features. The objective of this study was to evaluate audiologic outcomes for patients who were initially implanted with an AB Clarion 1.2 internal device and underwent CIR for technology upgrade or device failure. METHODS: Retrospective chart review was performed at a single academic medical center for patients (pediatric and adult) with an AB Clarion 1.2 internal device who underwent CIR to a later generation AB internal device and had available audiologic data. RESULTS: Forty-eight individuals with a Clarion 1.2 implant underwent CIR. Pre- and post-CIR speech understanding did not change for AzBio (p-value = 0.11, mean change = 12.1%, 95% CI = -2.9-27.2%), CNCw (p-value = 0.74, mean change = -1%, 95% CI = -10.4-12.4%), or HINT (p-value = 0.12, mean change = 19.9%, 95% CI = -2.6-42.4%) scores. Pure-tone averages improved following CIR (p-value < 0.01, mean change = 4.3 dB, 95% CI = 1.5-7.1 dB). CONCLUSIONS: Revision of AB Clarion 1.2 cochlear implants does not significantly worsen audiologic outcomes and may improve hearing in some individuals, but individual patient-level outcomes are variable.

Combining Fat and Implants for Gluteal Augmentation.

Guidelines for optimal buttock implant management, time-efficient preparation of implant pocket, and breakdown of optimal implant choice, combined with large-volume fat transfer for best possible outcome.

Deformable titanium for acetabular revision surgery: a proof of concept.

Custom-made triflange acetabular implants are increasingly used in complex revision surgery where supporting bone stock is diminished. In most cases these triflange cups induce stress-shielding. A new concept for the triflange is introduced that uses deformable porous titanium to redirect forces from the acetabular rim to the bone stock behind the implant and thereby reduces further stress-shielding. This concept is tested for deformability and primary stability.Three different designs of highly porous titanium cylinders were tested under compression to determine their mechanical properties. The most promising design was used to design five acetabular implants either by incorporating a deformable layer at the back of the implant or by adding a separate generic deformable mesh behind the implant. All implants were inserted into sawbones with acetabular defects followed by a cyclic compression test of 1800N for 1000 cycles.The design with a cell size of 4 mm and 0.2 mm strut thickness performed the best and was applied for the design of the acetabular implants. An immediate primary fixation was realized in all three implants with an incorporated deformable layer. One of the two implants with a separate deformable mesh needed fixation with screws. Cyclic tests revealed an average additional implant subsidence of 0.25 mm that occurred in the first 1000 cycles with minimal further subsidence thereafter.It is possible to realize primary implant fixation and stability in simulated large acetabular revision surgery using a deformable titanium layer behind the cup. Additional research is needed for further implementation of such implants in the clinic.

Identification and treatment of potentially destabilizing Vancouver B-lesser trochanter periprosthetic fracture ("New B2"): A 33-case series.

INTRODUCTION: A new type of periprosthetic fracture, between Vancouver-SoFCOT types A and B, was recently described and labeled "new B2". It occurs intraoperatively or in the early postoperative period, on cementless implants, and features a posteromedial cortical fragment around the lesser trochanter. The main aim of the present study was to report clinical and radiological results in a series of 33 cases of what is better called Vancouver B-lesser trochanter (VB-LT) fracture. The secondary objective was to identify risk factors. The study hypothesis was that VB-LT fracture might occur in the late postoperative course. MATERIAL AND METHOD: A2 single-center retrospective study included all patients with postoperative periprosthetic VB-LT fracture diagnosed on standard X-ray. Treatment was operative or non-operative depending on femoral implant subsidence and the patient's general health status. RESULTS: There were 33 VB-LT fractures out of 445 periprosthetic femoral fractures (7.5%), in 27 women and 6 men; all were postoperative, at a mean 47 months (range, 1 day to 20 years). Mean subsidence of the femoral stem was 8.8mm, in 73% of cases (24 out of 33 implants). The 9 VB-LT1 fractures (without subsidence) were treated non-operatively, without secondary displacement. Thirteen of the 24 VB-LT2 fractures (with subsidence) were managed by stem exchange and cerclage; 3 other patients had isolated stem exchange, 2 had isolated internal fixation by cerclage, and 6 in poor health were managed non-operatively. At a mean 28 months' follow-up (range, 6-48 months), mean PMA score was 15.5 (range, 10-18), Harris Hip score 72.4 (range, 43-100) and Parker score 7.2 (range, 4-9). All cases showed osseointegration and implant stability; there was 1 case of non-union, without impact on stability. CONCLUSION: Postoperative Vancouver B-lesser trochanter fracture seemed specific to cementless implants and did not occur exclusively in the early postoperative period. Non-operative treatment gave good results when there was no implant subsidence (type VB-LT1). LEVEL OF EVIDENCE: IV, retrospective.

Magnet dislocation following magnetic resonance imaging in cochlear implant users: Diagnostic pathways and managment.

OBJECTIVES: Although modern cochlear implants (CIs) are approved for magnetic resonance imaging (MRIs) adverse events still occur with unacceptable frequency. Methods: In this retrospective study, magnet displacement due to MRIs was analysed. Relevant factors e.g. symptoms during MRI, diagnostics, surgical intervention following the diagnosis and possible subsequent damage were assessed. RESULTS: 16 patients were enclosed. All patients complained about pain while the scan was conducted. Computed tomography (CT) scans of the temporal bone or X-rays of the skull were performed to confirm diagnosis. Artefacts on CT scans delayed immediate diagnosis in some cases. DISCUSSION: Despite various studies demonstrating the range of adverse events related to CIs following MRI, little information is available on diagnosis and radiologic recognition of magnet dislocation. In patients complaining about pain following an MRI scan an X-ray of the head should be performed immediately. Most adverse events occur in radiological centres without expertise in cochlear implants. CONCLUSION: Comprehensive training of patients, surgeons and radiologists is the most efficient tool to prevent damage to the CI and the patient. X-ray of the skull is suggested to be used as the method of choice in imaging.

Revision rates of trapeziometacarpal total joint arthroplasty in relation to occupational hand force requirements.

The purpose was to determine revision rates after trapeziometacarpal total joint arthroplasty in working age patients, hypothesizing that higher occupational hand force requirements lead to higher revision rates. We conducted a follow-up study of patients operated 2003-2015. Self-reported job titles at the time of primary surgery were linked with a job exposure matrix to estimate occupational hand force requirements. Time until revision was analysed using Cox regression. The study comprised 222 patients aged 39-65 years (mean 55, SD 6), including 133 patients in the labour market. The median follow-up period was 5 years (interquartile range 4-7) and the overall revision rate was 5/100 person-years. For high versus low occupational hand force requirements, the hazard ratio was 1.5 (95% confidence interval 0.5-4.4). For patients outside the labour market, the hazard ratio was 2.3 (0.9-5.6). Our results did not indicate large effects of high occupational hand force requirements on revision rates.Level of evidence: IV.

Acetabular complications are the most common cause for revision surgery following proximal femoral endoprosthetic replacement : what is the best bearing option in the primary and revision setting?

AIMS: Proximal femoral endoprosthetic replacements (PFEPRs) are the most common reconstruction option for osseous defects following primary and metastatic tumour resection. This study aimed to compare the rate of implant failure between PFEPRs with monopolar and bipolar hemiarthroplasties and acetabular arthroplasties, and determine the optimum articulation for revision PFEPRs. METHODS: This is a retrospective review of 233 patients who underwent PFEPR. The mean age was 54.7 years (SD 18.2), and 99 (42.5%) were male. There were 90 patients with primary bone tumours (38.6%), 122 with metastatic bone disease (52.4%), and 21 with haematological malignancy (9.0%). A total of 128 patients had monopolar (54.9%), 74 had bipolar hemiarthroplasty heads (31.8%), and 31 underwent acetabular arthroplasty (13.3%). RESULTS: At a mean 74.4 months follow-up, the overall revision rate was 15.0%. Primary malignancy (p < 0.001) and age < 50 years (p < 0.001) were risk factors for revision. The risks of death and implant failure were similar in patients with primary disease (p = 0.872), but the risk of death was significantly greater for patients who had metastatic bone disease (p < 0.001). Acetabular-related implant failures comprised 74.3% of revisions; however, no difference between hemiarthroplasty or arthroplasty groups (p = 0.209), or between monopolar or bipolar hemiarthroplasties (p = 0.307), was observed. There was greater radiological wear in patients with longer follow-up and primary bone malignancy. Re-revision rates following a revision PFEPR was 34.3%, with dual-mobility bearings having the lowest rate of instability and re-revision (15.4%). CONCLUSION: Hemiarthroplasty and arthroplasty PFEPRs carry the same risk of revision in the medium term, and is primarily due to acetabular complications. There is no difference in revision rates or erosion between monopolar and bipolar hemiarthroplasties. The main causes of failure were acetabular wear in the hemiarthroplasty group and instability in the arthroplasty group. These risks should be balanced and patient prognosis considered when contemplating the bearing choice. Dual-mobility, constrained bearings, or large diameter heads (> 32 mm) are recommended in all revision PFEPRs. Cite this article: Bone Joint J 2021;103-B(10):1633-1640.

Age stratified, matched comparison of unicompartmental and total knee replacement.

BACKGROUND: Unicompartmental knee replacement (UKR) tends to provide better function but has a higher revision rate than total knee replacement (TKR). The aim was to determine if this occurred in all age groups. METHODS: Two large, non-registry, prospective cohorts with median 10-year follow-up (2252 TKR, 1000 medial UKR) were identified. All UKR met recommended indications. TKR with an inappropriate disease pattern for medial UKR were excluded. Knees were propensity score-matched within age-strata (<60 years at operation, 60 to <75, 75+) and compared using Oxford Knee Score (OKS), Kaplan-Meier revision rates and a composite failure, defined as any of revision, reoperation or no improvement in OKS. RESULTS: One thousand five hundred and eighty-two TKR and UKR were matched. Results are reported TKR vs UKR for ages <60, 60 to <75 and 75+. Median 10-year OKS were 33 vs 45 (p < 0.001), 36 vs 42 (p < 0.001) and 36 vs 38 (p = 0.25). Ten-year revision rates were 11% vs 7%, 5% vs 5%, and 5% vs 10%, (none significant). The composite failures occurred 8%, 5% and 5% more frequently with TKR than UKR (none significant). CONCLUSIONS: In this matched study UKR provided better functional outcomes in all age groups, particularly the young, and provided substantially more excellent outcomes. Although in older groups TKR tended to have a lower revision rate, in the young UKR had a lower revision rate. This was surprising and was perhaps because in this study UKR was, as recommended, only used for bone-on-bone arthritis, whereas in young patients it is widely used for early arthritis, which is associated with a high failure rate. This study supports the use of UKR with recommended indications, in all age groups.

Influence of treatment modality on morbidity and mortality in periprosthetic femoral fracture. A comparative study of 71 fractures treated by internal fixation or femoral implant revision.

INTRODUCTION: The incidence of periprosthetic femoral fracture is constantly increasing, with high associated morbidity and mortality. Surgical treatment is guided by the Vancouver classification, but the influence of type of treatment on morbidity and mortality has been little analyzed. The theoretical advantage of implant revision over internal fixation is that it should allow earlier weight-bearing, although the impact of this on morbidity and mortality and autonomy has not been demonstrated. We conducted a case-control study, to assess the influence of type of treatment (implant revision or internal fixation) (1) on mobility and autonomy and (2) on morbidity and mortality. HYPOTHESIS: The study hypothesis was that clinical results and morbidity and mortality do not differ between these two types of treatment. METHODS: A retrospective study included 70 patients with a total of 71 femoral periprosthetic fractures treated between 2007 and 2014. Two treatment groups, comparable for mean age, gender and ASA and Parker scores, were studied. Mean age was 78±13.5years (range, 23-95years). Thirty-six fractures (50.7%) were treated by implant revision via a posterolateral approach, using a revision stem with (n=11) or without cement (n=25) (REVISION group); immediate postoperative weight-bearing was authorized. Thirty-five fractures (49.3%) were treated by open reduction and internal fixation, using a locking plate (ORIF group); weight-bearing was authorized only in the third month. Mean follow-up was 43±27months (range, 0.75-107months). RESULTS: Autonomy on Parker score was reduced by 2 points at 1year's follow-up. Mean preoperative scores were 7.32±1.79 (range, 3-9) and 7.43±1.79 (range, 4-9) in the REVISION and ORIF group, respectively, (p=0.8), falling to 5.06±2.6 (range, 0-9) and 4.5±2.01 (range, 0-9) respectively at follow-up (p=0.349). Sixteen patients in the REVISION group versus 13 in the ORIF group had made adaptations in their home or changed place of residence (p=0.2). At last follow-up, 18 patients (28.6%) had died: 12 (37.5%) in the ORIF and 6 (19.3%) in the REVISION group (p<0.05). Survival with death as endpoint at a mean 3.5years was 88±11% in the REVISION group versus 51±11% in the ORIF group (p=0.02). Three implant replacements were performed in each group (p=0.83). Twelve medical or surgical complications occurred in the ORIF group (37.5%) and 11 in the REVISION group (34%) (p=0.9). CONCLUSION: Implant revision for periprosthetic femoral fracture showed significantly lower overall mortality than internal fixation, without difference in terms of treatment failure or complications requiring revision surgery. LEVEL OF EVIDENCE: Level III, case-control study.

Intra-cochlear electrode tip fold-over.

Cochlear implantation has been performed safely for over two decades but still has various minor and major complications. We report two cases of an unusual complication of electrode implantation: tip fold-over of the electrode array within the cochlea. Both cases required undergoing explantation and re-implantation. The frequent use of fine and pre-curved electrodes particularly with the use of an insertion tool necessitates routine postoperative radiological evaluation of the electrode array. Our cases demonstrate the benefit of systematic imaging including the possible use of the Cone Beam CT intraoperatively.

Practice-Based Patient Management Strategies in Gluteal Augmentation with Implants.

This article focuses on practice-based recommendations for surgeons performing gluteal augmentation with implants (GAI). Preoperative planning, including the indications, precautions, and contraindications to GAI, is discussed. Advantages and disadvantages of subfascial and intramuscular implantation are addressed along with recommendations for implant size, shape, and position. Recommendations for patient management before and after surgery along with operative and nonoperative strategies for postoperative complications, including wound dehiscence, infection, and seroma, are included. Aesthetic concerns and recommendations for the management of poor results are addressed. A comprehensive literature review is included along with illustrative preoperative and postoperative photos.

Histological evaluation of two designs of shoulder surface replacement implants.

AIMS: To assess the extent of osteointegration in two designs of shoulder resurfacing implants. Bony integration to the Copeland cylindrical central stem design and the Epoca RH conical-crown design were compared. PATIENTS AND METHODS: Implants retrieved from six patients in each group were pair-matched. Mean time to revision surgery of Copeland implants was 37 months (standard deviation (sd) 23; 14 to 72) and Epoca RH 38 months (sd 28; 12 to 84). The mean age of patients investigated was 66 years (sd 4; 59 to 71) and 58 years (sd 17; 31 to 73) in the Copeland and Epoca RH groups respectively. None of these implants were revised for loosening. RESULTS: Increased osteointegration was measured under the cup in the Copeland implant group with limited bone seen in direct contact with the central stem. Bone adjacent to the Epoca RH implants was more uniform. CONCLUSION: This difference in the distribution of bone-implant contact and bone formation was attributed to the Epoca implant's conical crown, which is positioned in more dense peripheral bone. The use of a central stem may not be necessary provided there is adequate peripheral fixation within good quality humeral bone. TAKE HOME MESSAGE: Poor osteointegration of cementless surface replacement shoulder prosthesis may be improved by implant design.