Fracture of a triple-polished tapered cemented femoral stem at the Morse taper after metal-on-metal primary total hip arthroplasty.

Total hip arthroplasty, one of the most successful orthopaedic procedures, is influenced by several variables. Corrosion at the modular junction is known as trunnionosis. Despite being reported infrequently, corrosion between the femoral head and the Morse taper can result in severe complications. Fracture of the femoral component in primary metal-on-metal (MoM) total hip arthroplasty at the Morse taper is an extremely rare event and can be associated with several risk factors. We report a case of corrosion at the Morse taper in a hybrid primary MoM total hip arthroplasty, resulting in Morse taper fracture with consequent femoral head entrapment inside the acetabular component. We hypothesise that some risk factors, such as age over 60years, active male patients, body mass index above 30kg/m2, large femoral heads, high-offset stems, 9/10 Morse taper and MoM-bearing surfaces, are associated with this mode of failure.

Gait instability may indicate liner failure in patients with total hip arthroplasty. A report of three cases.

Total hip arthroplasty is one of the most common and successful orthopaedic procedures performed worldwide. Uncemented modular acetabular components and highly cross-linked polyethylene liners are the implants of choice for most arthroplasty surgeons. However, despite their well-known benefits, highly cross-linked polyethylene liners are not without complications, such as rim fracture, rupture and dissociation. We report three patients with gait instability and radiographic subluxation due to highly cross-linked polyethylene liner failures evidenced during stage one revision surgery. The three patients were symptoms free, with no new instability episodes, and the radiographs showed no evidence of implant loosening at the most recent follow-up. Although it is a rare complication, these three cases highlight the importance of suspecting and evaluating highly cross-linked polyethylene liner failures in patients referred for gait instability with no history of previous trauma.

Six-stage revision surgery of a triple periprosthetic joint infection due to a delayed diagnosis of a bilateral psoas abscess: a case report.

CASE: We present a case of a 70-year-old woman with simultaneous periprosthetic joint infection (PJI) of both hips and left knee due to a bilateral psoas abscess. The patient underwent debridement and implants removal with the consequent reimplantation in a sequential six-stage revision surgery. At four years of follow-up and in spite of the patient's comorbidities and current PJI presentation, she maintains full activities of daily living without restrictions. CONCLUSION: Accurate and early diagnosis of a psoas abscess is crucial. This case report provides experience of a complex scenario, the decision-making involved and the outcomes of an underdiagnosed complication.

Metaphyseal debonding of the Corail collarless cementless stem: report of 18 cases and case-control study.

AIMS: The Corail stem has good long-term results. After four years of using this stem, we have detected a small group of patients who have presented with symptomatic metaphyseal debonding. The aim of this study was to quantify the incidence of this complication, to delineate the characteristics of patients presenting with this complication and to compare these patients with asymptomatic controls to determine any important predisposing factors. PATIENTS AND METHODS: Of 855 Corail collarless cementless stems implanted for osteoarthritis, 18 presented with symptomatic metaphyseal debonding. A control group of 74 randomly selected patients was assembled. Clinical and radiological parameters were measured and a logistic regression model was created to evaluate factors associated with metaphyseal debonding. RESULTS: The prevalence of this complication was 2.1% in our series. In the multivariable model, the presence of a Dorr B-type proximal femur was associated with metaphyseal debonding (odds ratio (OR) 10.73, 95% confidence interval (CI) 2.31 to 49.97, p = 0.002), as was a body mass index > 25 kg/m2 (OR 6.85, 95% CI 1.06 to 44.28, p = 0.04). Smaller stems and the use of a polyethylene acetabular liner appeared to be protective when compared with metal and ceramic setting hard-on-hard bearings. CONCLUSION: We have described an uncommon but important mode of failure of the Corail stem. Surgeons should be aware of this phenomenon; overweight patients with Dorr B-type femurs and in whom hard bearings are used appear to be particularly at risk. Cite this article: Bone Joint J 2017;99-B:1435-41.

Bilateral simultaneous femoral neck fracture mimicking abdominal pain in a cerebral palsy patient.

Simultaneous bilateral femoral neck fractures are unusual lesions, generally associated with an underlying condition which causes impaired bone mineralization, triggered by an increased bone stress. We present a 24-year-old cerebral palsy patient, who was previously evaluated in another institution due to inability to walk, interpreted as abdominal pain. No alteration in blood analysis or abdominal X-rays was found. As no response to treatment was observed, a new abdominal X-ray was taken, which incidentally depicted bilateral medial femoral neck fracture. He was referred to our practice after a resection arthroplasty was offered in another institution. After admission, bilateral one-stage THA was performed. Several reports emphasize bone disease as a major precipitating factor, and there is an increased incidence of hip fractures in chronic epilepsy, renal osteodystrophy, and chronic steroid use. Femoral head resection has been proven to be effective in immobilized patients, whereas this was not a reasonable option in this patient who presented walking ability. Despite the treatment election, primary care physicians should be aware of and alert to the possibility of fractures in patients with neurological disorders and calcium metabolism alterations. Late diagnosis of orthopedic injuries in this type of patients may lead to permanent disability.

The use of femoral struts and impacted cancellous bone allograft in patients with severe femoral bone loss who undergo revision total hip replacement: a three- to nine-year follow-up.

We determined the midterm survival, incidence of peri-prosthetic fracture and the enhancement of the width of the femur when combining struts and impacted bone allografts in 24 patients (25 hips) with severe femoral bone loss who underwent revision hip surgery. The pre-operative diagnosis was aseptic loosening in 16 hips, second-stage reconstruction in seven, peri-prosthetic fracture in one and stem fracture in one hip. A total of 14 hips presented with an Endoklinik grade 4 defect and 11 hips a grade 3 defect. The mean pre-operative Merle D'Aubigné and Postel score was 5.5 points (1 to 8). The survivorship was 96% (95% confidence interval 72 to 98) at a mean of 54.5 months (36 to 109). The mean functional score was 17.3 points (16 to 18). One patient in which the strut did not completely bypass the femoral defect was further revised using a long cemented stem due to peri-prosthetic fracture at six months post-operatively. The mean subsidence of the stem was 1.6 mm (1 to 3). There was no evidence of osteolysis, resorption or radiolucencies during follow-up in any hip. Femoral width was enhanced by a mean of 41% (19% to 82%). A total of 24 hips had partial or complete bridging of the strut allografts. This combined biological method was associated with a favourable survivorship, a low incidence of peri-prosthetic fracture and enhancement of the width of the femur in revision total hip replacement in patients with severe proximal femoral bone loss.

Viability of impacted bone allografts under metal mesh at the calcar in revision surgery of the hip.

Metal meshes are used in revision surgery of the hip to contain impacted bone grafts in cases with cortical or calcar defects in order to provide rotational stability to the stem. However, the viability of bone allografts under these metal meshes has been uncertain. We describe the histological appearances of biopsies obtained from impacted bone allografts to the calcar contained by a metal mesh in two femoral reconstructions which needed further surgery at 24 and 33 months after the revision procedure. A line of osteoid and viable new bone was observed on the surface of necrotic trabeculae. Active bone marrow between these trabeculae showed necrotic areas in some medullary spaces with reparative fibrous tissue and isolated reactive lymphocytes. This is interpreted as reparative changes after revascularisation of the cancellous allografts. These pathological findings are similar to those reported in allografts contained by cortical host bone and support the hypothesis that incorporation of morcellised bone under metal meshes is not affected by these devices.

Locking compression plate fixation of Vancouver type-B1 periprosthetic femoral fractures.

BACKGROUND: Fractures occurring at or near the distal tip of a hip prosthesis with a stable femoral stem (Vancouver type-B fractures) are associated with many complications because of the inherently unstable fracture pattern. Locking compression plates use screws that lock into the plate allowing multiple points of unicortical fixation. Such unicortical fixation may lower the risk of damage to the cement mantle or a stable femoral stem during the treatment of a periprosthetic femoral fracture. The purpose of this study was to analyze clinically and radiographically a group of patients with a Vancouver type-B1 periprosthetic femoral fracture treated with open reduction and internal fixation with use of a locking compression plate. METHODS: Fourteen consecutive patients (fourteen hips) with a Vancouver type-B1 periprosthetic femoral fracture were treated with a locking compression plate. There were five men and nine women with an average age of sixty-eight years at the time of fracture. All of the fractures occurred after a total hip arthroplasty performed with cement, and eleven of the arthroplasties were revisions. In addition to the plate, cortical strut allografts were used to stabilize five fractures. The patients were assessed clinically and radiographically. RESULTS: The average duration of follow-up was twenty months. Eight fractures healed uneventfully at an average of 5.4 months. Three treatment constructs failed with fracture of the plate within twelve months after surgery. An additional three constructs also failed because of plate pullout. All failures except one occurred in constructs in which a cortical strut allograft had not been utilized. CONCLUSIONS: On the basis of the high failure rate in this series of patients, locking compression plates do not appear to offer advantages over other types of plates in the treatment of type-B1 periprosthetic femoral fractures. Despite the potential to preserve the cement mantle, the locked screws did not appear to offer good pullout resistance in this fracture type. We believe that supplementation with strut allografts should be used routinely if this type of locking compression plate is selected to treat these fractures.

Separation of the apex hole eliminator screw in four failed hybrid total hip arthroplasties.

Advancement or separation of the apex hole eliminator screw in uncemented Duraloc 100 cups (DePuy, Warsaw, Indiana, USA) has been recently reported as a radiographic finding without clinical effects. We report 4 patients with a separation of the apex hole eliminator screw in Duraloc 300 uncemented cups and aseptic failures of a hybrid total hip arthroplasty (acetabular osteolysis and femoral stem loosening). Revision surgery was performed when disabling pain and radiographic signs of loose components were present. Although difficult to determine, a relationship between the screw migration and the failure could have existed in these cases. Migration of the screw might not only be interpreted as a radiographic, clinically irrelevant finding. Its presence should alert the orthopaedic surgeon that the prosthesis is exposed to high intraarticular fluid pressures.

Modular femoral head dissociation after dislocation and entrapment in reconstruction ring: a case report.

Dissociation of modular components is an infrequent potential complication characteristically unique to modularity. We present a patient in whom dissociation of the modular femoral head occurred at attempted closed reduction after dislocation, with the intraoperative findings including entrapment of the head between the rim of a reconstruction ring and the acetabular bone. In the case a dislocation in a patient that was previously reconstructed with a reinforcement ring and a modular femoral stem occurs, dissociation of the modular head should be considered as an extremely uncommon complication that does not outweigh the advantages given by modularity.

Acetabular reconstruction with impacted bone allografts and cemented acetabular components: a 2- to 13-year follow-up study of 142 aseptic revisions.

We reviewed the clinical and radiological results of 131 patients who underwent acetabular revision for aseptic loosening with impacted bone allograft and a cemented acetabular component. The mean follow-up was 51.7 months (24 to 156). The mean post-operative Merle D'Aubigné and Postel scores were 5.7 points (4 to 6) for pain, 5.2 (3 to 6) for gait and 4.5 (2 to 6) for mobility. Radiological evaluation revealed migration greater than 5 mm in four acetabular components. Radiological failure matched clinical failure. Asymptomatic radiolucent lines were observed in 31 of 426 areas assessed (7%). Further revision was required in six patients (4.5%), this was due to infection in three and mechanical failure in three. The survival rate for the reconstruction was 95.8% (95% confidence interval 92.3 to 99.1) overall, and 98%, excluding revision due to sepsis. Our study, from an independent centre, has reproduced the results of the originators of the method.