The clinical, radiological, microbiological, and molecular profile of the skin-penetration site of transfemoral amputees treated with bone-anchored prostheses.

The breach of the skin barrier is a critical issue associated with the treatment of individuals with transfemoral amputation (TFA) using osseointegrated, percutaneous titanium implants. Thirty TFA patients scheduled for abutment exchange or removal were consecutively enrolled. The aims were to determine the macroscopic skin signs, the presence of bacteria and the gene expression in abutment-adherent cells and to conduct correlative and comparative analyses between the different parameters. Redness and a granulation ring were present in 47% of the patients. Bacteria were detected in 27/30 patients, commonly in the bone canal. Staphylococcus aureus, coagulase-negative staphylococci, streptococci, and Enterococcus faecalis were the most common. A positive correlation was found between TNF-α expression and the detection of S. aureus. Staphylococcus aureus together with other bacterial species revealed a positive relationship with MMP-8 expression. A negative correlation was demonstrated between the length of the residual femur bone and the detection of a granulation ring and E. faecalis. A positive correlation was revealed between fixture loosening and pain and the radiological detection of endosteal bone resorption. Fixture loosening was also correlated with the reduced expression of interleukin-10 and osteocalcin. It is concluded that several relationships exist between clinical, radiological, microbiological, and molecular assessments of the percutaneous area of TFAs. Further long term studies on larger patient cohorts are required to determine the precise cause-effect relationships and unravel the role of host-bacteria interactions in the skin, bone canal and on the abutment for the longevity of percutaneous implants as treatment of TFA. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 578-589, 2017

Is there a reduction in risk of revision when 36-mm heads instead of 32 mm are used in total hip arthroplasty for patients with proximal femur fractures?: A matched analysis of 5,030 patients with a median of 2.5 years’ follow-up between 2006 and 2016 in the Nordic Arthroplasty Register Association

Background and purpose — 32-mm heads are widely used in total hip arthroplasty (THA) in Scandinavia, while the proportion of 36-mm heads is increasing as they are expected to increase THA stability. We investigated whether the use of 36-mm heads in THA after proximal femur fracture (PFF) is associated with a lower risk of revision compared with 32-mm heads.Patients and methods — We included 5,030 patients operated with THA due to PFF with 32- or 36-mm heads from the Nordic Arthroplasty Register Association database. Each patient with a 36-mm head was matched with a patient with a 32-mm head, using propensity score. The patients were operated between 2006 and 2016, with a metal or ceramic head on a polyethylene bearing. Cox proportional hazards models were fitted to estimate the unadjusted and adjusted hazard ratio (HR) with 95% confidence intervals (CI) for revision for any reason and revision due to dislocation for 36-mm heads compared with 32-mm heads.Results — 36-mm heads had an HR of 0.9 (CI 0.7–1.2) for revision for any reason and 0.8 (CI 0.5–1.3) for revision due to dislocation compared with 32-mm heads at a median follow-up of 2.5 years (interquartile range 1–4.4).Interpretation — We were not able to demonstrate any clinically relevant reduction of the risk of THA revision for any reason or due to dislocation when 36-mm heads were used versus 32-mm. Residual confounding due to lack of data on patient comorbidities and body mass index could bias our results.During the past years total hip arthroplasty (THA) has become the preferred treatment option for displaced femoral neck fractures in even younger (55–64 years) patients (Rogmark et al. 2017). Previous studies have shown an increased risk of revision, especially due to dislocation, in patients receiving THA after proximal femur fracture (PFF) compared with patients operated due to primary osteoarthritis (OA) (Conroy et al. 2008, Hailer et al. 2012). The risk of THA dislocation in fracture patients varies widely from as low as 5% (Tabori-Jensen et al. 2019), especially when dual mobility cups (DMCs) are used, up to 6–18% (Burgers et al. 2012, Johansson 2014, Noticewala et al. 2018) with conventional cups. The risk of THA revision due to dislocation has been reported as even lower, ranging from 0.5 to 0.7% in national register studies (Conroy et al. 2008, Hailer et al. 2012), as not all unstable THAs are revised. According to the above-mentioned studies, increased age, male sex, the use of a posterior approach, and smaller head sizes are associated with increased risk of revision due to dislocation. To counteract the risk of dislocation, bigger head sizes have been used as they increase the impingement-free range of motion (Burroughs et al. 2005, Tsuda et al. 2016) and jumping distance of THA (Sariali et al. 2009). During the past years, the use of larger heads in THA has increased with 28-mm continuously declining and 32- and 36-mm increasing (Tsikandylakis et al. 2018b). However, register studies performed on patients with displaced femoral neck fracture (Jameson et al. 2012, Cebatorius et al. 2015) have not demonstrated any superiority of larger heads over smaller ones regarding risk of revision, especially due to dislocation. This effect has only been demonstrated in studies performed on a case mix of hip diagnoses that have reported an increased risk of revision due to dislocation when 28-mm or smaller heads are used compared with 32-mm or larger heads (Hailer et al. 2012, Kostensalo et al. 2013).Most of the above-mentioned register studies have used 28-mm heads as reference, which are rarely used nowadays (Tsikandylakis et al. 2018b). Patients receiving THA after PFF have a higher risk for revision than patients with OA and should preferably be studied separately, setting 32 mm as contemporary standard of reference. We therefore investigated if increasing head size from 32 to 36 mm is associated with a decreased risk of revision, especially due to dislocation, in patients with PFF in the Nordic Arthroplasty Register Association (NARA) database. We hypothesized that the risk is lower when 36-mm heads ar</p

The role of head size in total hip arthroplasty - Dislocation, wear and cup stability

Large heads are used in total hip arthroplasty, with the aim of reducing the risk of dislocation, but there are concerns related to polyethylene wear, corrosion and cup loosening. Paper I is an observational study that aimed to investigate whether the transition from 28-mm to 32-mm heads and thereafter to 36-mm heads in patients undergoing total hip arthroplasty (THA) after osteoarthritis has been followed by a reduction in dislocation rates in the Nordic countries. The results showed that the use of 32-mm rather than 28-mm heads reduced the risk of revision due to dislocation. A further increase from 32- to 36-mm heads was not associated with any further reduction in the risk of revision due to dislocation. Paper II is an observational study that investigated whether there is a difference in the risk of revision due to dislocation between 2 propensity score matched groups of patients that had received a 36-mm or a 32-mm THA after femoral neck fracture. The results showed no difference. Paper III is a randomized, controlled trial that aimed to compare polyethylene wear, measured with roentgen stereophotogrammetry (RSA), between patients that underwent a THA with the largest possible metal head (36-44 mm) and patients with a 32-mm THA. There was no difference in polyethylene wear. Paper IV aimed to compare whole-blood cobalt, chromium and titanium levels between patients that had randomly received either the largest possible cobaltchromium head (36-44 mm) or a 32-mm cobalt-chromium head on a titanium stem. Whole-blood ion levels, as an indicator of taper corrosion, were very low and did not differ between the groups. Paper V aimed to investigate whether the increased frictional torques that are generated by the largest possible metal heads (36-44 mm) on highly cross-linked polyethylene bearings would compromise the fixation of cementless cups, compared with 32-mm heads. Using RSA, no difference in cup migration was found. The thesis concludes that the use of 32-mm heads in routine THA has provided greater stability than 28-mm heads. The use of 36-mm heads did not provide any additional stability. In patients with a femoral neck fracture, the use of 36- mm heads did not provide any additional stability either. In order to achieve even greater stability, even larger heads are probably required. The concerns about polyethylene wear, taper corrosion and cup loosening could not be confirmed by the results of the thesis, but longer-term results are warranted before drawing any definite conclusions about the safety of larger heads

Implant survival, adverse events, and bone remodeling of osseointegrated percutaneous implants for transhumeral amputees.

BackgroundOsseointegrated percutaneous implants provide direct anchorage of the limb prosthesis to the residual limb. These implants have been used for the rehabilitation of transhumeral amputees in Sweden since 1995 using a two-stage surgical approach with a 6-month interval between the stages, but results on implant survival, adverse events, and radiologic signs of osseointegration and adaptive bone remodeling in transhumeral amputees treated with this method are still lacking.Questions/purposesThis study reports on 2- and 5-year implant survival, adverse events, and radiologic signs of osseointegration and bone remodeling in transhumeral amputees treated with osseointegrated prostheses.MethodsBetween 1995 and 2010, we performed 18 primary osseointegrated percutaneous implants and two implant revisions in 18 transhumeral amputees; of those, 16 patients were available for followup at a minimum of 2 years (median, 8 years; range, 2-19 years). These include all transhumeral amputees who have received osseointegrated prostheses and represented approximately 20% of the all transhumeral amputees we evaluated for potential osseointegration during that time; general indications for this approach included transhumeral amputation resulting from trauma or tumor, inability to wear or severe problems wearing a conventional socket prosthesis, eg, very short residual limb, and compliant patients. Medical charts and plain radiographs were retrospectively evaluated.ResultsThe 2- and 5-year implant survival rates were 83% and 80%, respectively. Two primary and one revised implant failed and were removed because of early loosening. A fourth implant was partially removed because of ipsilateral shoulder osteoarthritis and subsequent arthrodesis. The most common adverse event was superficial infection of the skin penetration site (15 infections in five patients) followed by skin reactions of the skin penetration site (eight), incomplete fracture at the first surgery (eight), defective bony canal at the second surgery (three), avascular skin flap necrosis (three), and one deep implant infection. The most common radiologic finding was proximal trabecular buttressing (10 of 20 implants) followed by endosteal bone resorption and cancellization (seven of 20), cortical thinning (five of 20), and distal bone resorption (three of 20).ConclusionsThe implant system presented a survivorship of 83% at 5 years and a 38% 5-year incidence of infectious complications related to the skin penetration site that were easily managed with nonoperative treatment, which make it a potentially attractive alternative to conventional socket arm prostheses. Osseointegrated arm prostheses have so far only been used in transhumeral amputations resulting from either trauma or tumor. Their use has not been tested and is therefore not recommended in transhumeral amputations resulting from vascular disease. This method could theoretically be superior to socket prostheses, especially in transhumeral amputees with very short residual humerus in which the suspension of a conventional prosthesis is difficult. Comparative studies are needed to support its potential superiority. Moreover, the radiological findings in this study need to be followed over time because some of them are of uncertain long-term clinical relevance

Contemporary posterior surgical approach in total hip replacement: still more reoperations due to dislocation compared with direct lateral approach? An observational study of the Swedish Hip Arthroplasty Register including 156,979 hips

Background and purpose — The direct lateral approach (DLA) and the posterior approach (PA) are the most common surgical approaches in total hip replacement (THR) in Sweden. We investigated how the relationship between surgical approach and risk of reoperation due to dislocation has evolved over time. Patients and methods — Data were extracted from the Swedish Hip Arthroplasty Register from 1999 to 2014. We selected all THRs due to osteoarthritis with head sizes 28, 32, and 36 mm that were performed with either the DLA or the PA. Resurfacing prostheses were excluded. Kaplan–Meier curves for risk of reoperation due to dislocation and all-cause for the 2 surgical approaches were compared for 2 periods (1999–2006 and 2007–2014) up to 2 years postoperatively. We used Cox regression for sex, age, type of fixation, and head size to determine hazard ratios (HR) with DLA set as reference. Results — 156,979 THRs met the selection criteria. In 1999–2006, the PA was associated with increased risk of reoperation due to dislocation (HR 2.3, 95% CI 1.7–3.0) but there was no difference in the risk of all-cause reoperation (HR 1.1, CI 0.9–1.2). In 2007–2014 there was no statistically significant difference in the risk of reoperation due to dislocation (HR 1.2, CI 0.9–1.6) but the risk of all-cause reoperation was lower (HR 0.8, CI 0.7–0.9) for the PA. Interpretation — This study confirms historic reports on the increased risk of early reoperations due to dislocations using the PA compared with the DLA. However, in contemporary practice, the higher risk of reoperation due to dislocation associated with PA has declined, now being similar to that after DLA. We believe improved surgical technique for the PA may explain the results. Surprisingly, the PA was associated with lower risk of all-cause reoperation in 2007–2014. This finding warrants further investigation

Patient-reported Outcomes after Primary Total Hip Arthroplasty Are Not Affected by the Sex of the Surgeon : A Register-based Study of 8,383 Procedures in Western Sweden

Introduction: Female surgeons remain a minority within the field of orthopaedics, particularly in certain specialties such as arthroplasty. There is no scientific evidence on whether the surgeon's sex affects the patient-reported outcome after orthopaedic surgery such as total hip arthroplasty (THA). We therefore aimed to investigate the association between surgeon sex and health-related quality of life after THA.Methods:Data on primary THAs performed between 2008 and 2016 were collected from 10 hospitals in western Sweden. The data were linked with the Swedish Hip Arthroplasty Register, a regional patient register and the National Board of Health and Welfare, resulting in a data set that included surgeon-related and patient-related data. The outcome of the study was the change in health-related quality of life, measured with the 3-level version of EQ-5D (EQ-5D-3L) Index and EQ-visual analog scale (VAS), before and 1-year after THA. Mixed models, using hierarchical linear regression adjusted for patient sex, age, preoperative health-related quality of life and Charnley classification, were fitted to estimate the gain in EQ-5D-3L Index and EQ-VAS with 95% confidence intervals based on surgeon sex.Results:In total, 8,383 primary THAs were done for osteoarthritis by 193 surgeons. Of those, 37 were women and 156 were men. The regression model was showed that patients operated by female surgeons had a β-coefficient of gain in EQ-5D-3L Index of -0.001 (-0.022 to 0.021) and a β-coefficient of gain in EQ VAS of 0.004 (-0.023 to 0.030), compared with patients operated by male surgeons. Similar results were obtained in a sensitivity analysis including attendings only.Discussion:Patients undergoing primary THA reported similar gain in health-related quality of life regardless of surgeon sex. Based on our results, health-related quality of life after primary THA was not associated with the sex of the operating surgeon