Soft Tissue Reactions Research Articles

Influence of transmucosal designs of dental implant on tissue regeneration in beagle dogs

This study was conducted to evaluate the influence of concave machined and concave microgrooved profiles of the transmucosal portion of implants on early peri-implant tissue regeneration. We assessed implants with 3 different transmucosal profiles: the bevel group that had only a bevel in the transmucosal part, bioseal group and bioseal/groove group that had a micro-groove in the S-shaped portion of the implant. A total of 36 implants (12 of each type) were placed in the edentulous mandibular ridges of 6 beagle dogs. We used radiographs to investigate the mesio-distal change of the marginal bone. Bucco-lingual bone resorption and soft tissue reactions were evaluated histologically. Radiographic and histological analysis did not show any difference in mesio-distal or bucco-lingual marginal bone resorption among any of the 3 groups (p > 0.05). The bioseal and bioseal/groove groups had more rigid connective tissue attachment than that in the bevel group. However, the bevel group had significantly long junctional epithelium attachment and the bioseal and bioseal/groove groups had long connective tissue attachment (p < 0.05). Implants with S-shaped concavity of the transmucosal portion resulted in a firmer connective tissue barrier, and thus, a better soft tissue regeneration, than implants with straight bevel.

Comparison of Guided Bone Regeneration using a Bovine Collagen Membrane vs a Calcium Sulfate Barrier

ABSTRACTResorbable membranes have eliminated the need for re-entry for removal and reduce the incidence of adverse soft tissue reactions that accompany membrane exposure. However, the lack of rigidity often makes these more prone to collapse. Calcium sulfate has shown promise as a regenerative material alternative in a socket preservation application. The purpose of this study was to compare calcium sulfate and bovine collagen as a barrier in guided bone regeneration.Materials and MethodsEighteen sites were treated in this randomized, blinded clinical study. Patients were divided into 2 groups, 9 sites each. Group 1, had bovine collagen membrane (OssixTM) and group 2 had calcium sulfate barrier (CalcigenOralTM) to cover the graft. All sites were augmented with autogenously bone and demineralized freeze-dried bone composite graft at 1:1 ratio. Implants were placed in the grafted area 4 to 6 months post grafting. Vertical and horizontal ridge measurements were made before and after grafting by two blinded examiners.ResultsThe collagen membrane group had a mean bone gain of 1.06 ± 1.01 mm in width and 0.19 ± 1.11 mm in height. In comparison, the calcium sulfate group had a mean bone loss of –0.14 ± 0.74 mm in width and –0.19 ± 0.74 mm in height. Student t-test revealed a significant difference in width dimension between the two groups, p = 0.01.ConclusionOverall results of this study suggest that calcium sulfate might have limited use as barrier for ridge augmentation.How to cite this articleGhaly M, Kerns DG, Hallmon WW, Solomon ES, Nagy WW, Al-Hashimi I, Rossmann JA. Comparison of Guided Bone Regeneration using a Bovine Collagen Membranevsa Calcium Sulfate Barrier. J Contemp Dent 2013;3(3):138-143.

Aseptic Loosening of Pedicle Screw As a Result of Metal Wear Debris in a Pediatric Patient

This is a case report. To report a case of soft-tissue reaction to wear debris and osteolysis around a pedicle screw after posterior spine fusion in a pediatric patient. Posterior spine fusion with instrumentation is a standard procedure for stabilization and curve correction in patients with scoliosis. Late operative site pain accounts for the highest frequency of reoperation. Debris accumulation for steel and titanium constructs occurs at the pedicle screw-rod junction. Cellular reaction to metal wear may be responsible for osteolysis and aseptic loosening around spinal implants. A 14-year-old male patient with neurofibromatosis and right thoracic scoliosis of 50° underwent posterior spine fusion from T2 to T10. The postoperative course was complicated by continuous pain, and imaging studies demonstrated hardware failure, requiring a revision and subsequent development of a perihilar opacity of unknown origin. Further studies demonstrated hypermobility with adjacent soft-tissue reactivity and inflammation surrounding the right T5 transpedicle screw. After hardware removal, the patient's recovery was uneventful. Six months later, a repeated computed tomographic scan demonstrated resolution of the previously described soft-tissue mass and a satisfactory fusion of the thoracic spine. Metal wear debris can form in pediatric patients during the healing process after spinal fusions or when pseudarthrosis is present. Clinically, this manifests as back pain with a possible aseptic inflammatory abscess. Hardware removal can achieve resolution of symptoms and regression of inflammation.

Caveat Emptor: Adverse Inflammatory Soft-Tissue Reactions in Total Hip Arthroplasty with Modular Femoral Neck Implants

Modular femoral neck (MFN) implants in total hip arthroplasty facilitate optimizing femoral offset and version while minimizing femoroacetabular impingement1, but component fracture and dissociation have been reported with titanium-alloy MFN implants2-6. Cobalt-chromium MFN components have improved strength compared with earlier designs, but the long-term consequences of wear and corrosion at the femoral neck-stem junction are unknown3,7. Inflammatory metal-hypersensitivity reactions have been most frequently reported in cobalt-chromium metal-on-metal articulations used in total hip arthroplasty and hip resurfacing arthroplasty8,9, but to our knowledge, these reactions have not been described in MFN implants with metal-on-polyethylene articulations. We present two patients with MFN implants who developed partially cystic peri-implant soft-tissue masses with histologic features suggestive of metal hypersensitivity requiring revision arthroplasty. Both patients were informed that data concerning their cases would be submitted for publication, and they provided consent. Case 1. A sixty-three-year-old woman (body mass index, 31.3) with severe osteoarthritis had undergone a left total hip arthroplasty with a 50-mm Trilogy Shell (Zimmer, Warsaw, Indiana), a 36-mm highly crosslinked polyethylene liner (Zimmer), an uncemented titanium-alloy ABG II size-3 modular femoral stem with a 130° cobalt-chromium MFN (Stryker, Mahwah, New Jersey), and a +5-mm 36-mm cobalt-chromium head (Stryker). The patient had an uneventful postoperative course and was discharged on postoperative day three. Seven months later, the patient presented with progressive pain in the left hip. Radiographs showed satisfactory component positioning with no osteolysis, aseptic loosening, or periprosthetic fracture. Blood work showed an elevated erythrocyte sedimentation rate (ESR), C-reactive protein level (CRP), and serum metal ion levels without leukocytosis (Table I). Computed tomography (CT) of the hip demonstrated a 2.3 × 3-cm fluid collection between the gluteus maximus and medius muscles. Aspiration of the hip yielded 2 mL of orange-tainted …

Peri‐implant tissue reactions to immediate nonocclusal loaded implants with different collar design: an experimental study in dogs

The aim of this study was to evaluate bone remodelling and soft tissue reactions around immediate nonocclusal loaded implants with different collar configuration in beagle dogs. The mandibular bilateral second, third and fourth premolars of six beagle dogs were extracted. After 3 months of healing, four implants were placed in the mandibles of each dog. Randomly, two implants with a 1.5 mm polished surface collar (TSA, control group) and two implants with a 0.7 mm polished surface collar and 2.5 mm microthreaded area (TSAA, test group) were inserted. Both groups were treated with a minimal mucoperiosteal flap elevation approach. Impressions were taken and two single screw-retained restorations were inserted in each hemi-mandible 2 days after the implant placement. The animals were sacrificed at 1, 2 and 3 months (two specimens each), and biopsies were obtained. Samples were processed for ground sectioning. Histomorphometric analysis was carried out to compare buccal and lingual bone height loss and soft tissue behaviour between the two groups. Crestal bone resorption was significantly higher in the control group (P > 0.05). The establishment of the biological width showed similar outcomes for both groups. Only the distance from the top of the peri-implant mucosa to the apical portion of the barrier epithelium at lingual aspect was significantly more pronounced in the control group (P > 0.05). The alterations that occurred in the peri-implant tissues were related to the adaptation that occurred after the loading conditions in both groups. The microthread design might have an effect in maintaining the marginal bone loss against loading.

The Snare Technique: A Novel Atraumatic Method for the Removal of Difficult Nasal Foreign Bodies

BackgroundNasal foreign bodies (NFBs) are a common occurrence, particularly in children between 2 and 4 years old. Many techniques have been developed to remove NFBs, though intranasal batteries, in particular, possess characteristics such as round shape, smooth surface, and limited visibility that make attempts at removal significantly more difficult. In the context of intranasal batteries, a considerable local soft tissue reaction and potential necrosis may exist to further complicate removal. ObjectiveTo present a technique for removal of difficult intranasal foreign bodies that may be utilized by health care practitioners, particularly in the Emergency Department setting. Case ReportWe present a case of a 4-year-old child presenting with intranasal battery with mucosal necrosis. After conventional techniques failed, we utilized a novel wire snare technique to dissect the NFB free from the nasal mucosa safely and in an atraumatic fashion. ConclusionThis technique is noted to be a rapid, atraumatic, and effective means for the removal of difficult NFBs.

Metal-on-Metal Bearing: Is This the End of the Line? We Do Not Think So

Recent studies have recommended the discontinuation of metal-on-metal (MoM) components in total hip arthroplasty (THA) because of adverse effects reported with large-diameter MoM THA. This is despite favorable long-term results observed with 28 and 32mm MoM bearings. The aim of this study was to assess the value of calls for an end to MoM bearings as THA components. Specifically, we wish to address the risks associated with MoM bearings including adverse soft tissue reactions, metal ion release, and carcinogenic risk. The study evaluates the arguments in the literature reporting on MoM (adverse soft tissue reactions, metal ion release, and carcinogenic risk) and the experience of the current authors who re-introduced these bearings in 1995. They are balanced by a benefit-risk review of the literature and the authors' experience with MoM use. Adverse reactions to metallic debris as well as metal ion release are predictable and can be prevented by adequate design (arc of coverage, clearance), metallurgy (forged instead of cast alloy, high-carbide content), and appropriate component orientation. There is no scientific evidence that carcinogenicity is increased in subjects with MoM hip prostheses. MoM articulations appear to be attractive allowing safe hip resurfacing, decreasing the risk of THA revision in active patients, and providing secure THA fixation with cement in cages in severely deformed hips. MoM bearings in women of child-bearing age are controversial, but long-term data on metallic devices in adolescents undergoing spinal surgery seem reassuring. Adequate selection of MoM articulations ensures their safe use. These articulations are sensitive to orientation. Fifteen years of safe experience with 28- and 32-mm bearings of forged alloy and high-carbide content is the main reason for retaining them in primary and revision THA.

Paper 284: Double Bundle Anterior Cruciate Ligament Reconstruction Using a Polylactide Carbonate (CALAXO) Osteoconductive Interference Screw

The purpose of this study was to describe our experience of the new Polylactide Carbonate (Calaxo) Osteoconductive interference screw (Smith & Nephew) when used for both femoral and tibial graft fixation in Double Bundle ACL reconstruction. Since May 2006, patients with an ACL deficient knee were reconstructed using the Double Bundle technique. All were followed prospectively and outcome data collected. Evidence of fixation failure was established subjectively by clinical examination (Pivot Shift) and objectively via KT-1000 arthrometer. Following ethical approval, post-operative CT scans (immediate and 12-18 months) were performed on five (a further 5 awaited) patients allowing assessment of tunnel dimensions/fill. Twenty nine patients (26 male, 3 female) with a mean age of 30 (range 18-47) were included. At last follow-up, no evidence of graft/fixation failure was found; KT-1000 mean side-side difference 1.4mm (range −3 to +6). All patients had a positive pivot shift preoperatively which was abolished postoperatively. Subjective IKDC score was significantly improved with a mean of 76.27% (SD 17.38) at last review compared with 54.02% (SD 17.86) preoperatively (t (22) = −5.37, p<0.05) One patient had a postoperative infection with no other complications reported. Radiologically the screws did not show complete resorption in 2 cases, with significant tunnel widening found on 3 cases. Some evidence of new bone formation was noted but not found to be significant. We have shown satisfactory clinical results with use of the Calaxo screw when used in Double Bundle ACL Reconstruction. However, radiologically the ostoeconductive properties of the screw shown in the pre-clinical animal model were not evident. This study helps illustrate that preclinical animal data cannot necessarily be translated into human practice. Surgeons should proceed with caution when using new biological implants tested purely in animal models. Although we have not had any cases of the reported adverse local soft tissue reaction associated with Calaxo, we support Smith & Nephew's decision to withdraw the screw from clinical use.

Aseptic Lymphocyte Dominated Vasculitis-Associated Lesion Resulting From Trunnion Corrosion in a Cobalt-Chrome Unipolar Hemiarthroplasty

Most of the published descriptions of adverse soft tissue reactions that have been reported in the context of a metal-on-metal articulation have been in cases of total hip arthroplasty or resurfacing arthroplasty. Recently, several case reports have been published describing aseptic lymphocyte dominated vasculitis-associated lesions (ALVAL) in metal-on-polyethylene. To our knowledge, there has not been a description of a similar, aggressive reaction secondary to metal debris from the head-neck junction of a unipolar hemiarthroplasty component. In this case report, we describe a patient with a catastrophic failure of a unipolar hip hemiarthroplasty, secondary to aggressive osteolysis and an inflammatory mediated immunological reaction to metal debris.

Metal-on-Metal Total Hip Arthroplasty: Causes and High Incidence of Early Failure

Early failures of metal-on-metal total hip arthroplasty (THA) occur due to aseptic loosening, metal hypersensitivity reactions, pseudotumor formation, and component seizing. The purpose of this study was to investigate the timing, common modes of failure, clinical outcomes, and incidence of metal-on-metal THA revisions. A review was performed of 80 patients who underwent revision of a failed metal-on-metal THA for any reason. The most common reason for metal-on-metal failure was aseptic acetabular loosening, with a rate of 56.25% (45/80 patients). Early failure of metal-on-metal THAs was noted, with 78% of these revisions being performed within 2 years of the index operation and 92.5% within 3 years. Furthermore, 13% of patients experienced significant localized soft tissue reactions. Mean preoperative Harris Hip Score was 42.35 ± 14.24 and mean postoperative Harris Hip Score was 66.5 ± 23.2 (range, 9.55-95.4), with an average follow-up of 438 ± 492 days (range, 40-2141), or 1.2 years.It is imperative that clinicians be cognizant of the fact that the proposed advantages of metal-on-metal THA are not without potential detrimental sequelae. This article proposes an algorithm to aid in diagnosing the etiology of a painful metal-on-metal THA, as well as 2 classification schemes regarding metal-on-metal THA complications to help direct treatment.

Immediate prostheses on one-piece trans-mucosal implants in flapless surgical procedures Case Series Report. Part I: full arch rehabilitations

Aim The aim of the present case series report is to illustrate a clinical technique and present the application of onepiece transmucosal implants in flapless surgical procedures, supporting full arch immediate prostheses. Materials and methods A total of 294 implants (Xive TG, Friadent, Germany) have been used to support full arch immediate prostheses, over the last six years and have been in function for at least one year. The surgical placement of five or more implants per case involved immediate extraction and intrasocket flapless placement, combined with minimal flap elevation in the areas of healed extraction sites (43 mandibular and 7 maxillary arches). In all cases immediate provisionalization followed. Detailed three-dimensional cone-beam localized volumetric tomography preceeded the surgical procedures. The delivery of the final ceramo-metal prostheses was accomplished within a 20 day period. Results Six implants failed to osseointegrate. All other implants are still successfully bearing the final prosthesis for the time that they have been followed. Soft tissue reaction was favorable from both the biologic and esthetic point of view. Conclusion The flapless placement of one piece implants into edentulous healed sites is a predictable procedure in the presence of abundance of supporting bone as confirmed by 3-D imaging. On the other hand, immediate extraction placement of one piece implants allows the engagement of sound bone located deeper into the socket and provides adequate mechanical support of the soft tissue architecture that is preserved predictably. In all cases the prosthetic procedures are accomplished without disturbing the hardsoft tissue interface as the abutment-prosthesis interface is coronally elevated by the virtual design of the implant.

Early Failure of a Ceramic-on-Metal Total Hip Arthroplasty: A Case Report.

The total hip arthroplasty procedure has improved substantially over the past two decades, including the design, materials used, and the fixation. Minimizing bearing surface wear has become a determinant of long-term implant survival. Approaches to minimize bearing surface wear have included improvement in polyethylene as well as the introduction of hard-on-hard bearing couples. Presently, the most commonly used hard bearing surfaces include metal-on-metal (MOM) and ceramic-on-ceramic (COC) couples. Both have excellent tribological properties, but they also have limitations. Second-generation MOM articulations have lower wear rates compared with metal-on-ultra-high-molecular-weight polyethylene (UHMWPE)1-3. However, despite lower volumetric wear, the wear particles are very small and their presence locally and systemically is concerning4-11. COC articulations have better wear properties than MOM and UHMWPE couples12-17, but issues such as squeaking18,19 and implant fracture remain problematic16,20,21. In the hope of overcoming the adverse issues of MOM and COC bearing couples, an innovative ceramic-on-metal (COM) articulation, utilizing a ceramic head and metal liner, has been recently introduced. Proposed advantages of COM couples include reduced wear, with resultant lower serum metal ion levels compared with MOM12,17,22-24, although COM and COC couples have similar wear rates12,24,25. Adverse soft-tissue reactions are a well-known complication of MOM hip resurfacing arthroplasty7,26-28 as well as contemporary MOM total hip arthroplasty29,30. Such soft-tissue reactions have not been reported with COM bearings; however, these devices have had limited use and only short-term follow-up. We report the case of a patient who experienced early failure of a COM total hip arthroplasty. The patient was informed that data concerning her case would be …

Extraoral Implants in the Rehabilitation of Craniofacial Defects: Implant and Prosthesis Survival Rates and Peri-Implant Soft Tissue Evaluation

Few reports have evaluated cumulative survival rates of extraoral rehabilitation and peri-implant soft tissue reaction at long-term follow-up. The objective of this study was to evaluate implant and prosthesis survival rates and the soft tissue reactions around the extraoral implants used to support craniofacial prostheses. A retrospective study was performed of patients who received implants for craniofacial rehabilitation from 2003 to 2010. Two outcome variables were considered: implant and prosthetic success. The following predictor variables were recorded: gender, age, implant placement location, number and size of implants, irradiation status in the treated field, date of prosthesis delivery, soft tissue response, and date of last follow-up. A statistical model was used to estimate survival rates and associated confidence intervals. We randomly selected 1 implant per patient for analysis. Data were analyzed using the Kaplan-Meier method and log-rank test to compare survival curves. A total of 150 titanium implants were placed in 56 patients. The 2-year overall implant survival rates were 94.1% for auricular implants, 90.9% for nasal implants, 100% for orbital implants, and 100% for complex midfacial implants (P = .585). The implant survival rates were 100% for implants placed in irradiated patients and 94.4% for those placed in nonirradiated patients (P = .324). The 2-year overall prosthesis survival rates were 100% for auricular implants, 90.0% for nasal implants, 92.3% for orbital implants, and 100% for complex midfacial implants (P = .363). The evaluation of the peri-implant soft tissue response showed that 15 patients (26.7%) had a grade 0 soft tissue reaction, 30 (53.5%) had grade 1, 6 (10.7%) had grade 2, and 5 (8.9%) had grade 3. From this study, it was concluded that craniofacial rehabilitation with extraoral implants is a safe, reliable, and predictable method to restore the patient's normal appearance.

Long-term follow-up and metal ion trend of patients with metal-on-metal total hip arthroplasty

Long-term studies are required to support the use of metal-on-metal (MoM) bearings in total hip arthroplasty (THA) given the concern about systemic metal ion release and reports of adverse local soft tissue reactions. The purpose of this study was to report the seven to 13-year clinical, radiographic, and metal ion results in patients following MoM THA. We studied 163 prostheses after second-generation MoM THA between July 1997 and November 2003. Cobalt and chromium metal ions were collected using whole and analysed by inductively-coupled plasma-mass spectrometry. The mean follow-up was 8.87 years (range, 7-13 years). Four hips (2.5 %) were revised. The Kaplan-Meier survivorship was 91.3 % for revision for all causes, and 97.5 % when excluding the hips revised for a manufacturer's defect. Median whole blood cobalt levels peaked at a value of 2.87 μg/L at four years (p < 0.0001 vs. pre-operative) and subsequently decreased to 2.0 μg/L after nine years (p = 0.002 vs. four years). Median chromium levels maximally increased up to 0.75 μg/L after five years (p < 0.0001 vs. pre-operative) and tended to decrease thereafter to values of 0.56 μg/L after seven years. This seven to 13-year follow-up study indicates that the clinical and radiological results following MoM THA are satisfactory with low revision rates. Cobalt and chromium ion levels peaked at four and five years, respectively, and gradually decreased thereafter.

Independent predictors of revision following metal-on-metal hip resurfacing

Modern metal-on-metal hip resurfacing has been widely performed in the United Kingdom for over a decade. However, the literature reports conflicting views of the benefits: excellent medium- to long-term results with some brands in specific subgroups, but high failure rates and local soft-tissue reactions in others. The National Joint Registry for England and Wales (NJR) has collected data on all hip resurfacings performed since 2003. This retrospective cohort study recorded survival time to revision from a resurfacing procedure, exploring risk factors independently associated with failure. All patients with a primary diagnosis of osteoarthritis who underwent resurfacing between 2003 and 2010 were included in the analyses. Cox’s proportional hazard models were used to analyse the extent to which the risk of revision was related to patient, surgeon and implant covariates. A total of 27 971 hip resurfacings were performed during the study period, of which 1003 (3.59%) underwent revision surgery. In the final adjusted model, we found that women were at greater risk of revision than men (hazard ratio (HR) = 1.30, p = 0.007), but the risk of revision was independent of age. Of the implant-specific predictors, five brands had a significantly greater risk of revision than the Birmingham Hip Resurfacing (BHR) (ASR: HR = 2.82, p &lt; 0.001, Conserve: HR = 2.03, p &lt; 0.001, Cormet: HR = 1.43, p = 0.001, Durom: HR = 1.67, p &lt; 0.001, Recap: HR = 1.58, p = 0.007). Smaller femoral head components were also significantly more likely to require revision (≤ 44 mm: HR = 2.14, p &lt; 0.001, 45 to 47 mm: HR = 1.48, p = 0.001) than medium or large heads, as were operations performed by low-volume surgeons (HR = 1.36, p &lt; 0.001). Once these influences had been removed, in 4873 male patients &lt; 60 years old undergoing resurfacing with a BHR, the five-year estimated risk of revision was 1.59%. In summary, after adjustment for a range of covariates we found that there were significant differences in the rate of failure between brands and component sizes. Younger male patients had good five-year implant survival when the BHR was used.

Evidence-Based Understanding of Management Perils for Metal-on-Metal Hip Arthroplasty Patients

Adverse biological reactions causing failures of metal-on-metal (MoM) hip arthroplasty can be local or systemic. Both dose-dependent cytotoxicity of wear debris leading to subsequent necrosis of periprosthetic soft tissues and adaptive immunity may play an important role in pathogenesis in susceptible patients. There appears to be a spectrum of clinical presentations of adverse soft tissue reactions, reflecting a complex interplay of implant, surgical, and patient factors. A systematic treatment approach is helpful in optimizing evidence-based management of MoM patients. Although specialized tests such as metal ion levels are a useful diagnostic tool for evaluating MoM hip arthroplasty patients, overreliance on any single investigative tool in clinical decision-making process should be avoided. Future research focusing on diagnostic tools for detecting adverse periprosthetic soft tissue necrosis as well as optimization of MoM bearings and modular connections to further diminish wear and corrosion is warranted.

Erratum to: Reaction of facial soft tissues to treatment with a Herbst appliance

Erratum to: Reaction of facial soft tissues to treatment with a Herbst appliance

Lipogranuloma of the Head and Neck

Objective : To report a rare case of lipogranuloma of the head & neck. Case Report : We present a 33-year old female patient with a 2-month history of left neck mass refractory to antibiotic therapy. Laboratory workup and fine needle aspiration biopsy was nondiagnostic. Excisional biopsy revealed histologic evidence of a granulomatous soft tissue reaction consistent with lipogranuloma. Lipogranuloma is a very rare finding in the head and neck which typically manifests clinically with painless palpable lymphadenopathy. Two mechanisms have been described for the etiology of lipogranulomas: (1) an exogenous foreign body reaction to either a lipid or oil-like substance, and the more rare (2) endogenous degeneration secondary to an allergic/inflammatory mechanism as a result of severe heat/cold and/or trauma. Given the patient’s history of motor vehicle accident 3 months prior with concurrent neck strain injury, the etiology of lipogranuloma is this case is likely due to endogenous lipid degeneration. Conclusion : This case reports the rare clinical finding of a patient with lipogranuloma likely secondary to endogenous inflammatory lipid degeneration.

In vivo evaluation of edge-loading in metal-on-metal hip resurfacing patients with pseudotumours

ObjectivesPseudotumours (abnormal peri-prosthetic soft-tissue reactions) following metal-on-metal hip resurfacing arthroplasty (MoMHRA) have been associated with elevated metal ion levels, suggesting that excessive wear may occur due to edge-loading of these MoM implants. This study aimed to quantify in vivo edge-loading in MoMHRA patients with and without pseudotumours during functional activities.MethodsThe duration and magnitude of edge-loading in vivo was quantified during functional activities by combining the dynamic hip joint segment contact force calculated from the three-dimensional (3D) motion analysis system with the 3D reconstruction of orientation of the acetabular component and each patient’s specific hip joint centre, based on CT scans.ResultsEdge-loading in the hips with pseudotumours occurred with a four-fold increase in duration and magnitude of force compared with the hips without pseudotumours (p = 0.02).ConclusionsThe study provides the first in vivo evidence to support that edge-loading is an important mechanism that leads to localised excessive wear (edge-wear), with subsequent elevation of metal ion levels in MoMHRA patients with pseudotumours.

Adverse reactions to metal debris: histopathological features of periprosthetic soft tissue reactions seen in association with failed metal on metal hip arthroplasties

AimTo describe the histopathology of localised adverse reactions to metal debris (ARMD) seen in association with failed metal on metal (MoM) hip arthroplasties. The nature of aseptic lymphocytic vasculitis associated...