Soft Tissue Reactions Research Articles

Higher Blood Cobalt and Chromium Levels in Patients With Unilateral Metal-on-Metal Total Hip Arthroplasties Compared to Hip Resurfacings

BackgroundAdverse soft tissue reactions in metal-on-metal (MoM) hip replacements are associated with cobalt (Co) and chromium (Cr) ions in blood. We report the prevalence and risk factors for elevated blood Co and Cr levels in patients with a unilateral MoM hip. MethodsFrom a single institution, blood Co and Cr levels were analyzed in 1748 patients (692 hip resurfacings and 1056 total hip arthroplasties [THAs]). Concentrations exceeding 7 ppb were considered elevated, and the risk factors for elevated levels were calculated with binary logistic regression. ResultsElevated blood metal ion levels were more common in MoM THA than in resurfacing patients (17.4% vs 5.9%, P < .001), and in 5 of the 7 THA brands, more than 20% of patients had elevated metal ion concentrations, whereas the proportion was less than 10% in all hip resurfacings. In resurfacings, small femoral head (odds ratio [OR] 1.30 per millimeter decrease [CI, 1.12-1.49]), high acetabular inclination (OR 1.15 per degree increase [CI 1.09-1.22]), and young age (OR 1.05 per year decrease [1.02-1.10]) were independent risk factors for elevated ions. In the THA group, female gender (OR 2.04 [CI 1.35-3.06]), longer time between surgery and ion measurement (OR 1.19 per year increase [CI 1.05-1.34]), and large headsize (OR 1.07 per millimeter increase [CI 1.01-1.13]) were risk factors for elevated ions. ConclusionGiven the high percentage of elevated levels, the systematic surveillance of especially large diameter MoM THAs seems justified.

Erratum to: Stability, survival, and tolerability of a 4.5-mm-wide bone-anchored hearing implant: 6-month data from a randomized controlled clinical trial

The objective of this study was to compare the stability, survival, and tolerability of 2 percutaneous osseointegrated titanium implants for bone conduction hearing: a 4.5-mm diameter implant (test) and a 3.75-mm diameter implant (control). Fifty-seven adult patients were included in this randomized controlled clinical trial. Sixty implants were allocated in a 2:1 (test-control) ratio. Follow-up visits were scheduled at 7, 14, 21, and 28 days; 6 and 12 weeks; and 6 months. At every visit, implant stability quotient (ISQ) values were recorded by means of resonance frequency analysis (RFA) and skin reactions were evaluated according to the Holgers classification. Implants were loaded with the bone conduction device at 3 weeks. Hearing-related quality of life was evaluated using the Abbreviated Profile of Hearing Aid Benefit (APHAB), the Glasgow Benefit Inventory (GBI), and the Glasgow Health Status Inventory (GHSI). ISQ values were statistically significantly higher for the test implant compared to the control implant. No implants were lost and soft tissue reactions were comparable for both implants. Positive results were reported in the hearing-related quality of life questionnaires. These 6-month results indicate that both implants and their corresponding hearing devices are safe options for hearing rehabilitation in patients with the appropriate indications. Loading at 3 weeks did not affect the stability of either implant.

Clinical results of Cochlear™ BIA300 in children: Experience in two tertiary referral centers

ObjectivesTo evaluate clinical outcomes of the Cochlear™ BIA300 in the pediatric population. Study designHistorical cohort study. SettingTwo tertiary referral centers. PatientsAll patients implanted with the BIA300 from November 2011 to January 2014 and 17 years or younger during surgery were included in this cohort study. Main outcome measuresNumber of soft tissue reaction scores according to Holgers, local and systemic treatment of soft tissue reactions, revision surgeries and implant loss. ResultsSince introduction of the BIA300, 79 children have been implanted in both centers. During the mean follow-up of 11.7 months per implant, 15.7% of 115 implants received at least two local treatments for peri-abutment soft tissue reactions. Moreover, in 32 implants an adverse soft tissue reaction (Holgers 2 or higher) was noted at least once. In 28.7% of implants one or multiple revision surgeries were required. Implant loss occurred in 4 patients (3.5% of all implants), additionally, in five children the abutment had to be removed because of persistent soft tissue problems. ConclusionsThe current study confirms good implant survival for these implants in pediatric patients. The number of adverse soft tissue reactions found in the current study resembles numbers reported on previous generation implants and abutments in children. However, for revision surgery (soft tissue revision and/or abutment change), an increase in frequency is noticed compared to reported results on previous generation implants and abutments, whether this is the result of the new implant or other factors cannot be concluded on the current series. The total aspect of the presented data are of importance in the decision making for a specific type of percutaneous bone anchored hearing implant.

Evaluation of Soft Tissue Reaction to Corundum Ceramic Implants Infiltrated with Colloidal Silver.

Corundum ceramic is a biomaterial used as a bone graft substitute. Silver is a well known antiseptic substance with many practical, clinical applications. The aim of this study was to estimate soft tissue (in vivo) reaction to a new kind of ceramic implants. In our experiment, we examined the soft tissue reaction after implantation of corundum ceramic infiltrated with colloidal silver in the back muscles of 18 Wistar rats. The use of colloidal silver as a coating for the implant was designed to protect it against colonization by bacteria and the formation of bacterial biofilm. In our study, based on the experimental method, we performed implantation operations on 18 Wistar rats. We implanted 18 modified ceramic implants and, as a control group, 18 unmodified implants. As a follow up, we observed the animals operated upon, and did postoperative, autopsy and histopathological examinations 14, 30, 90 and 180 days after implantation. We didn't observe any pathological reactions and significant differences between the soft tissue reaction to the modified implants and the control group. Lack of pathological reaction to the modified implants in the living organism is the proof of their biocompatibility. This is, of course, the first step on the long path to introduce a new kind of biocompatible ceramic implant with antiseptic cottage. Our experiment has an only introductory character and we plan to perform other, more specific, tests of this new kind of implant.

Genetic alterations in periprosthetic soft-tissue masses from patients with metal-on-metal hip replacement

Adverse soft tissue reactions in patients with metal-on-metal (MoM) hip replacement are associated with cobalt (Co) and chromium (Cr) particles released from the implant. Exposing the patients to long periods of increased metal ions concentrations resulting from the wear of these implants poses an increased risk of genotoxicity/mutagenicity. A variable proportion of patients develop periprosthetic soft-tissue masses or pseudotumors at the site of the implant. There is a concern that exposure to increased metal ions could increase the risk of cancer. In order to investigate whether the periprosthetic soft-tissue mass harbours any cancer- related genetic alterations, we studied DNA isolated from periprosthetic tissues of 20 patients with MoM hip replacement, for copy number alterations and mutations in hotspot regions of 50 cancer genes using aCGH and amplicon-based next generation sequencing.Our results showed copy number gains at 12q14.3 and 21q21.1in tumour from patient diagnosed with liposarcoma. Copy number alterations in periprosthetic tissues were seen in three other patients, one had a region of gain at 9q24.1 affecting JAK2 and INSL6, and two patients had region of gain at 6p21.1, affecting RUNX2. Mutation analysis showed V1578del mutation in NOTCH1 in two patients. The copy number alterations and mutations seen in periprosthetic soft-tissue masses are earlier reported in either haematological malignancies or in osteoblast related bone dysplasia. The presence of genetic anomalies was associated with longer in-situ time of the implant. Our findings warrant the need of similar studies in larger patient cohorts to evaluate the risk of development of neoplastic alterations in periprosthetic tissues of patients with MoM hip replacement.

Three-week loading of the 4.5 mm wide titanium implant in bone anchored hearing systems

PurposeThe purpose of this study is to assess implant stability, implant loss, adverse skin reactions and quality of life benefit following surgical implantation and early processor loading (3-weeks post-implantation) of the Oticon Ponto 4.5mm osseointegrated auditory implant. This study also investigates the relationship between the type of post-operative skin reactions and the gender, BMI and medical co-morbidities of participants. Materials/MethodsUsing a prospective, multicenter design, thirty adult patients 18years or older who met medical and audiological candidacy for an osseointegrated auditory bone-anchored hearing device were evaluated. They underwent simultaneous implantation of the Oticon 4.5mm wide implant and a 3.75mm sleeper implant. Sound processor loading occurred at three weeks post-implantation. Implant stability was measured using Radio Frequency Analysis (RFA) at surgery, 1, 3, 6, 12, 26 and 52weeks. The Glasgow Benefit Inventory was used to assess quality of life benefit at 12 and 52weeks following implantation. ResultsThe results show a positive linear trend in implant stability measures in all subjects over time. There have been no implant losses with early 3-week loading. Skin reactions were limited to grade 0 and 1 of the modified Holger's grading scale.Due to the limited incidence of complications, no conclusion can be made regarding the relationship between patient demographic data and soft tissue reaction. ConclusionOur findings confirm the safety and efficacy of early loading of the Oticon 4.5mm wide implant. Participants showed satisfaction with the earlier use of their processor with no added complications after one year post-implantation.

Loading of osseointegrated implants for bone conduction hearing at 3 weeks: 3-year stability, survival, and tolerability.

The objective of this study was to ascertain the long-term safety of loading osseointegrated implants for bone conduction hearing 3 weeks post-surgery. Thirty consecutive adult patients were implanted with the Baha BI300 (Cochlear Bone Anchored Solutions) in our tertiary referral center. Implants were loaded with the sound processor 3 weeks post-surgery. Follow-up examinations were performed at 10 days; 3, 4, 6, 8, and 12 weeks; 6 months; and 1, 2, and 3 years after implant surgery. At each follow-up visit, implant stability quotient (ISQ) values were recorded by means of resonance frequency analysis, and soft tissue status was evaluated according to Holgers’ classification. ISQ trends, implant survival, and soft tissue reactions were compared to a population of 52 patients with the same type of implants loaded from 6 weeks post-surgery as part of another study. Subjective benefit was measured by means of the Glasgow Benefit Inventory (GBI). After an initial dip in ISQ at 10 days after implantation, a gradually increasing trend in ISQ was found until 6 months in both populations, after which ISQ values remained above baseline values. Implant survival was 97 % in the study population and 96 % in the comparison population. Clinically relevant soft tissue reactions were found in 0.9 % (study population) and 1.7 % (comparison population) of all visits. Patients reported subjective benefit; the mean GBI score was 22.8. In conclusion, loading these implants at 3 weeks post-surgery is safe based on the current study, as long-term results show high ISQ values and good implant survival and tolerability.

Adverse local tissue reactions in metal-on-polyethylene total hip arthroplasty due to trunnion corrosion: the risk of misdiagnosis.

Adverse reaction to wear and corrosion debris is a cause for concern in total hip arthroplasty (THA). Modular junctions are a potential source of such wear products and are associated with secondary pseudotumour formation. We present a consecutive series of 17 patients treated at our unit for this complication following metal-on-highly cross-linked polyethylene (MoP) THA. We emphasise the risk of misdiagnosis as infection, and present the aggregate laboratory results and pathological findings in this series. The clinical presentation was pain, swelling or instability. Solid, cystic and mixed soft-tissue lesions were noted on imaging and confirmed intra-operatively. Corrosion at the head-neck junction was noted in all cases. No bacteria were isolated on multiple pre- and intra-operative samples yet the mean erythrocyte sedimentation rate was 49 (9 to 100) and C-reactive protein 32 (0.6 to 106) and stromal polymorphonuclear cell counts were noted in nine cases. Adverse soft-tissue reactions can occur in MoP THA owing to corrosion products released from the head-neck junction. The diagnosis should be carefully considered when investigating pain after THA. This may avoid the misdiagnosis of periprosthetic infection with an unidentified organism and mitigate the unnecessary management of these cases with complete single- or two-stage exchange.

A computational approach to fretting wear prediction at the head–stem taper junction of total hip replacements

Wear is one of the main reasons for failure of modular total hip replacements. Recent evidence suggests that fretting wear occurs at the taper junction which provides fixation between the prosthesis femoral head and stem components. The fine metallic wear debris that is released can lead to adverse soft-tissue reactions which can necessitate a revision surgery. The present study proposes a computational methodology utilising an energy wear law and a 3D finite element model to predict fretting wear at the taper junction. The method is novel in that it simulates the weakening of the initial taper ‘fixation’ (created at impaction of the head onto the stem in surgery) due to the wearing process. The taper fixation is modelled using a contact analysis with overlapped meshes at the taper junction. The reduction in fixation is modelled by progressive removal of the overlap between components based on calculated wear. The fretting wear analysis approach has been shown to model the evolution of wear effectively; however, it has been shown that accurate, quantitative values for wear are critically dependant on mesh refinement, wear scaling factor and fraction, wear coefficient used and knowledge of the device loading history. The method has been implemented with a 3D finite element model of the taper junction of a commercial total hip replacement. This has been used to determine taper wear patterns, wear damage and wear rates which have been shown to be consistent with those found from observation and measurement of retrieved prostheses. The numerical method could be used to consider the effect of design changes and clinical technique on subsequent fretting wear in modular prosthetic devices.

Current expert views on metal-on-metal hip resurfacing arthroplasty. Consensus of the 6th advanced Hip resurfacing course, Ghent, Belgium, May 2014.

This paper reports the consensus of an international faculty of expert metal-on-metal (MoM) hip resurfacing surgeons, with a combined experience of over 40,000 cases, on the current status of hip resurfacing arthroplasty. Indications, design and metallurgy issues, release of metal ions and adverse soft tissue reactions to particles, management of problematic cases and revisions, as well as required experience and training are covered. The overall consensus is that MoM hip resurfacing should not be banned and should be viewed separately from MoM total hip arthroplasty (THA) with a large diameter head because of the different design and wear behaviour related to the taper/trunnion connection. The use of hip resurfacing has decreased worldwide but specialist centres continue to advocate hip resurfacing in young and active male patients. Regarding age the general recommendation is to avoid hip resurfacing in men older than 65 and in women older than 55, depending on the patient activity and bone quality. Female gender is considered a relative contraindication. Most surgeons would not implant a MoM hip in women who would still like a child. Regardless of gender, there is a consensus not to perform hip resurfacing in case of a femoral head size smaller than 46 mm and in patients with renal insufficiency or with a known metal allergy. Regarding follow-up of hip resurfacing and detection of adverse local tissue reactions, metal ion measurements, MRI and ultrasound are advocated depending on the local expertise. The consensus is that hip resurfacing should be limited to high volume hip surgeons, who are experienced in hip resurfacing or trained to perform hip resurfacing in a specialist centre.

A Retrospective Cohort Study on the Influence of Comorbidity on Soft Tissue Reactions, Revision Surgery, and Implant Loss in Bone-anchored Hearing Implants.

To identify risk factors for complications after bone-anchored hearing implant (BAHI) surgery. Retrospective cohort study. Tertiary referral center. All adult patients who received titanium bone-anchored hearing implants at our clinic between September 1, 1988 and December 31, 2007 were approached to fill out a questionnaire on comorbidity factors. A total of 581 patients with 669 implants were included in the analysis. Implant loss, soft tissue reactions, and revision surgery after BAHI implantation. Skin disease and profound learning difficulties were risk factors for time to first soft tissue reaction, hazard rate ratio of 3.41 (95% CI 1.45-8.01) and 3.42 (1.03-11.39), respectively. Female gender showed a trend toward a negative risk for time to first soft tissue reaction, hazard rate ratio 0.60 (0.35-1.03). In multivariable analysis, skin disease and female gender were observed as independent associative factors, adjusted hazard ratio 3.08 (1.32-7.16) and 0.56 (0.33-0.94). For revision surgery, female gender and cardiovascular disease were identified as negative risk factors in univariable analysis, and smoking showed a trend toward a negative risk, with hazard ratios of 0.15 (0.07-0.32), 0.07 (0.03-0.20), and 0.51 (0.24-1.07), respectively. In multivariable analysis, smoking and female gender were observed as independent associative factors, adjusted hazard ratio 0.45 (0.22-0.95) and 0.14 (0.06-0.30). Smoking could be identified as a risk factor for implant loss with a hazard ratio of 3.32 (1.36-8.09). Retrospective analysis of comorbidity factors and clinical outcomes revealed risk factors for postoperative complications after BAHI surgery.

Bone-anchored Hearing Implant Surgery: Randomized Trial of Dermatome Versus Linear Incision Without Soft Tissue Reduction--Clinical Measures.

Assessment of differences in soft tissue healing and long-term issues between two techniques for bone-anchored hearing implant (BAHI) surgery. Single-center, randomized, nonblinded study using balanced randomization (1:1). Tertiary referral center in the Central Denmark Region. Forty-seven adults with normal skin quality. Operation with a BAHI system with randomization to 1) dermatome technique with soft tissue removal and 2) linear incision with no soft tissue reduction. Holgers' score, pain, and sensibility loss assessed at 0, 3, 7, 10, 14, and 21 days and 1, 3, 6, and 12 months postoperatively. Implant loss. Forty-nine patients were randomized (linear incision, n = 25; dermatome, n = 24). Forty-seven patients were analyzed (linear incision, n = 25; dermatome, n = 22). Differences in proportions for grouped data (outcome 0 and outcome >0) for the total of all visits were Holgers' Index: 0.13 (p = 0.0004; 95% confidence interval [95% CI], 0.058-0.21); sensibility loss: 0.50 (p = 2.2 · 10; 95% CI, 0.42-0.58); pain: 0.096 (p = 0.006; 95% CI, 0.026-0.17). Soft tissue reactions and pain were most prominent in the early postoperative period, whereas issues with sensibility loss subsided throughout the 1-year follow-up period. No implants were lost. In a randomized trial for BAHI surgery, the linear incision with no subcutaneous reduction had a faster healing time and inflicted less pain and sensibility loss than the dermatome technique. The long-term soft tissue problems were similar in the two groups, thus favoring the linear incision, which is less invasive.

Anterior Glenoid Rim Fracture Following Use of Resorbable Devices for Glenohumeral Stabilization.

BackgroundResorbable anchors are widely used in arthroscopic stabilization of the shoulder as a means of soft tissue fixation to bone. Their function is to ensure repair stability until they are replaced by host tissue. Complications include inflammatory soft tissue reactions, cyst formation, screw fragmentation in the joint, osteolytic reactions, and enhanced glenoid rim susceptibility to fracture.PurposeTo evaluate resorption of biodegradable screws and determine whether they induce formation of areas with poor bone strength that may lead to glenoid rim fracture even with minor trauma.Study DesignCase series; Level of evidence, 4.MethodsThis study evaluated 12 patients with anterior shoulder instability who had undergone arthroscopic stabilization with the Bankart technique and various resorbable anchors and subsequently experienced redislocation. The maximum interval between arthroscopic stabilization and the new dislocation was 52 months (mean, 22.16 months; range, 12-52 months). The mean patient age was 31.6 years (range, 17-61 years). The persistence or resorption of anchor holes; the number, area, and volume of osteolytic lesions; and glenoid erosion/fracture were assessed using computed tomography scans taken after redislocation occurred.ResultsComplete screw resorption was never documented. Osteolytic lesions were found at all sites (mean diameter, 5.64 mm; mean depth, 8.09 mm; mean area, 0.342 cm2; mean volume, 0.345 cm3), and all exceeded anchor size. Anterior glenoid rim fracture was seen in 9 patients, even without high-energy traumas (75% of all recurrences).ConclusionArthroscopic stabilization with resorbable devices is a highly reliable procedure that is, however, not devoid of complications. In all 12 patients, none of the different implanted anchors had degraded completely, even in patients with longer follow-up, and all induced formation of osteolytic areas. Such reaction may lead to anterior glenoid rim fracture according to the literature and as found in 75% of the study patients with local osteolysis (9/12). Reducing anchor number and/or size may reduce the risk of osteolytic areas and anterior glenoid rim fracture.

Femoral diameter and stem type are independent risk factors for ARMD in the large-headed ASR THR group.

BackgroundAdverse soft-tissue reaction to metal debris (ARMD) continues to be major source of concern in metal-on-metal (MoM) hip replacements. In our earlier study we were able to establish several risk factors for ARMD in patients who had received a small-diameter (<50 mm) Articular Surface Replacement (ASR, DePuy, Warsaw, IN, USA). The aims of the present study were to analyze whether these previously established risk factors also apply to patients who have received a large-headed (>50 mm) ASR™ XL THR.MethodsLarge-headed ASR total hip replacements were used in 225 operations (196 patients) at our institution. 176 patients (203 hips) attended a screening programme, consisting of a clinical evaluation, whole blood cobalt and chromium measurements, and cross-sectional imaging.ResultsRevision surgery was performed on 84 hips (37%) in 75 patients. ARMD was diagnosed in the majority (n = 73 [87%]) of these revisions. Cumulative 8-year survivorship was 52%. The previously established risk factors for ARMD were not applicable. Interestingly, increasing femoral diameter and stem type were identified as independent risk factors for ARMD but reduced cup coverage had no significant association with ARMD.ConclusionsStem type and increasing femoral size as independent risk factors for ARMD in the cohort of ASR XL THR patients, support the importance of taper failure in the development of ARMD. The present results suggest that the degree of taper failure may be variable and dependent on the taper design.

Diagnosis and therapy of particle disease in total hip arthroplasty

Particle disease is caused by periarticular accumulation of attrition particles and the inflammatory reaction of the body's tissue. This process may result in osteolysis or soft tissue transformation which presents itself symptomless in the beginning and can proceed to aseptic implant loosening, fracture, implant breaking as a result of the inappropriate osseous support and to algetic and destructive soft tissue reactions as well. Attrition particles originate from tribological pairing, and the extent of the attrition or the particle concentration depend on different factors as there are the tribological pairing's material, the head size, the patient's level of activity, and the implant position. Attrition particles can also be found in the range of any modular connection. Particle disease and its resulting morphological alterations of the tribological pairing is one of the most frequent reasons for re-operation in hip endoprosthetics.

Stability, survival, and tolerability of a 4.5-mm-wide bone-anchored hearing implant: 6-month data from a randomized controlled clinical trial.

The objective of this study was to compare the stability, survival, and tolerability of 2 percutaneous osseointegrated titanium implants for bone conduction hearing: a 4.5-mm diameter implant (test) and a 3.75-mm diameter implant (control). Fifty-seven adult patients were included in this randomized controlled clinical trial. Sixty implants were allocated in a 2:1 (test–control) ratio. Follow-up visits were scheduled at 7, 14, 21, and 28 days; 6 and 12 weeks; and 6 months. At every visit, implant stability quotient (ISQ) values were recorded by means of resonance frequency analysis (RFA) and skin reactions were evaluated according to the Holgers classification. Implants were loaded with the bone conduction device at 3 weeks. Hearing-related quality of life was evaluated using the Abbreviated Profile of Hearing Aid Benefit (APHAB), the Glasgow Benefit Inventory (GBI), and the Glasgow Health Status Inventory (GHSI). ISQ values were statistically significantly higher for the test implant compared to the control implant. No implants were lost and soft tissue reactions were comparable for both implants. Positive results were reported in the hearing-related quality of life questionnaires. These 6-month results indicate that both implants and their corresponding hearing devices are safe options for hearing rehabilitation in patients with the appropriate indications. Loading at 3 weeks did not affect the stability of either implant.

A ten-year review of soft tissue reactions around percutaneous titanium implants for auricular prosthesis.

Soft tissue reactions around abutments are the most common complications of percutaneous osseointegrated implants. The main objective of this study was to review our series of osseointegrated implants, evaluate the degree of adverse skin reactions around the auricular abutments, and compare with skin reactions in the pediatric bone-anchored hearing aid (BAHA) population. The reason for comparing these two groups was the difference in abutment shape and position in skin with different characteristics. A retrospective case analysis of 131 patient notes. We retrospectively studied 131 pediatric and adult patients who underwent an osseointegrated auricular prosthesis over a 10-year period (1997-2007). There were 95 adults and 36 children who had been implanted and fitted with an auricular prosthesis during the 10-year study period. All patients were followed up postoperatively for a 2-year minimum up to a 14-year maximum follow-up. Thirteen (13/36, 36%) children and seven adults (7/95, 7%) had a skin reaction around the ear prosthesis. The literature review has supported our study results and has shown that children have higher skin reactions in both BAHA and auricular prostheses than adults. Adverse skin reactions in the pediatric auricular group were significantly lower that the pediatric BAHA group. 4

Use of bone graft replacement in spinal fusions

The rationale for the increasing use of bone graft replacement lies in the need for increased graft volume, the avoidance of typical autograft donor site morbidity, and the potential improvement of fusion rates in revision and complex reconstructive surgery. The purpose of this work is to offer the spinal surgeon an evidence-based guide for choosing the appropriate grafting material and for using it effectively. Evidence-based overview of physical and biological properties, clinical indications and results of osteoconductive and osteoinductive bone replacement materials. The ideal bone replacement material should be osteoinductive and conductive, non-pathogenic, minimally antigenic, and (if required) mechanically stable. Compared to autograft, vascularization and remodeling of the fusion mass are delayed using allograft. Allogenous bone and demineralized bone matrix (DBM) possess limited osteoinductive properties and carry the risk of potential infectious disease transmission. Plasma-rich plasma (PRP) and bone marrow aspirate are commonly used in conjunction with an osteoconductive carrier materials. On-label use of bone morphogenetic proteins (BMPs) is currently restricted to mono- and bisegmental anterior lumbar fusion. The fusion rates obtained with BMPs match those of autologous bone graft. Potential risks of rhBMP in clinical use include soft tissue reactions, radiculitis and potentially increased risk of cancer. Osteoconductive ceramics (HA, CC, CS, ß-TCP) are useful graft extenders and carriers for bone growth enhancers and antibiotics. Osteoconductive bioceramics with different mechanical and biological properties are available for use as graft extenders. In a defined group of anterior interbody fusion procedures (ACDF, ALIF), satisfactory fusion rates (> 90%) may be obtained with exclusive use of graft extenders, whereas their solitary use in posterolateral fusions is not advisable. Genuine bone replacement is currently feasible with BMPs. Their use should be restricted to specific indications such as complex revision surgery and pseudarthrosis.

Adverse reaction to metal debris after Birmingham hip resurfacing arthroplasty

Background and purpose — Concern has emerged about local soft-tissue reactions after hip resurfacing arthroplasty (HRA). The Birmingham Hip Resurfacing (BHR) was the most commonly used HRA device at our institution. We assessed the prevalence and risk factors for adverse reaction to metal debris (ARMD) with this device.Patients and methods — From 2003 to 2011, BHR was the most commonly used HRA device at our institution, with 249 implantations. We included 32 patients (24 of them men) who were operated with a BHR HRA during the period April 2004 to March 2007 (42 hips; 31 in men). The mean age of the patients was 59 (26–77) years. These patients underwent magnetic resonance imaging (MRI), serum metal ion measurements, the Oxford hip score questionnaire, and physical examination. The prevalence of ARMD was recorded, and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.7 (2.4–8.8) years.Results — 6 patients had a definite ARMD (involving 9 of the 42 hips). 8 other patients (8 hips) had a probable ARMD. Thus, there was definite or probable ARMD in 17 of the 42 hips. 4 of 42 hips were revised for ARMD. Gender, bilateral metal-on-metal hip replacement and head size were not factors associated with ARMD.Interpretation — We found that HRA with the Birmingham Hip Resurfacing may be more dangerous than previously believed. We advise systematic follow-up of these patients using metal ion levels, MRI/ultrasound, and patient-reported outcome measures.

Experience of bone-anchored hearing aid implantation in children younger than 5 years of age

ObjectiveTo assess the practicality and benefit of Bone-anchored hearing aid (BAHA®) implantation in children younger than 5 years of age. FDA approval for use of BAHA® only exists for children 5 years of age and older. Their use in Australia is also rare, however their use for younger children is approved by the European Union. We wish to share our experience of implantation in an antipodean setting in this age group. MethodsInstitutional board approval was obtained for this study. All children undergoing BAHA® implantation under 5 years old were included from our prospective database. We examined the variety of surgical techniques, (including skin grafting, limited soft tissue reduction and no soft tissue reduction), BAHA® implants and abutments used, and use of the new series 400 hydroxyapatite coatings. Demographic data obtained included age at surgery, follow up duration, gender, ethnicity and indication for surgery. Anonymous benefit questionnaires (Glasgow children's benefit inventory (GCBI) and parents’ evaluation of aural performance of children (PEACH)) were completed online as well as a questionnaire on device use. Complications recorded included soft tissue reactions, implant loss/removal, abutment replacement/removal. We also assessed whether patient weight, ethnicity or socioeconomic status were risk factors for these complications. Results24 Children (26 ears/26 implants) under five years were identified from the database and included in the study. There was a 14:10 male to female ratio. Patient caregivers reported subjective benefit and improved quality of life (QOL) despite setbacks and complications related to BAHA® usage. 10/24 (42%) of children required treatment for significant peri-implant skin reactions whilst 25% required replacement of their abutments and/or implants. An increased risk of major complication was associated with socioeconomic deprived backgrounds and in patients of New Zealand Maori and Pacific Island ethnicity but not in patients with increased weight centiles. ConclusionsThe BAHA® implant and hearing aid system is of value to children under age 5 years. Parents tolerate the skin reactions and complications because of the perceived benefit in hearing and quality of life. Careful counselling of parents of potential young BAHA® implant candidates is necessary in light of this.