Conversion of a fused hip to total hip arthroplasty

BACKGROUND: Arthrodesis of the hip remains a viable treatment for severe unilateral arthritis after traumatic injury or infection in a young but otherwise healthy individual. The goal of the present study was to review the long-term clinical and radiographic results after conversion of a fused hip to a total hip arthroplasty and to identify the risk factors that would lead to a higher rate of failure. METHODS: We performed a retrospective review of the charts and radiographs of 187 patients (208 hips) who had conversion of a fused hip to a total hip arthroplasty. The mean duration of follow-up after the conversion to total hip arthroplasty was 9.2 years (range, two to twenty-six years). RESULTS: The mean age at time of the arthroplasty was fifty-one years. The mean time-interval between the arthrodesis and the conversion to a total hip arthroplasty was twenty-seven years. According to the information in the charts, at a mean duration of follow-up of 9.2 years after the total hip arthroplasty, 79% of hips were either pain-free or had minimal pain, 83% had good-to-excellent function, and 79% had good-to-excellent range of motion. Complications, which included fifteen nerve palsies, occurred in twenty-four hips. Twenty-eight hips had heterotopic ossification, but it was not associated with a recurrence of ankylosis or a marked reduction of motion. Revision arthroplasty was performed in twelve hips. The probability of survival of the implant was 96.1% (95% confidence interval, 91.5% to 98.2%) at ten years, 89.9% (95% confidence interval, 85.3% to 96.1%) at fifteen years, and 72.8% (95% confidence interval, 36% to 90.6%) at twenty-six years. CONCLUSIONS: Conversion of a fused hip to a total hip arthroplasty has a favorable outcome. However, the technically demanding nature of the procedure should not be underestimated. Patients should be cautioned with regard to the possibility of a higher rate of complications than that seen with primary total hip arthroplasty.     

Management of hip fractures using a dynamic hip screw

Authors describe the history of the dynamic hip screw and analyse the hip fracture. The operative technique of the DHS is described in details. In an analysis of the material of the Wilhelminenspital it is stressed that in the last years the DHS became dominant in the treatment of hip fractures. The treatment of four different types of fractures with DHS is demonstrated. The method is compared with other methods suitable for the treatment of hip fractures and it is stated that the less complications can be expected from the use of the DHS. On the basis of this comparison it is shown that the DHS is worthy to occupy a decisive place in the treatment of hip fractures.     

Insertion of a prosthetic hip into a total hip allograft. Case report

We describe a patient in whom a total hip replacement had failed and who subsequently fractured her proximal femur. The prosthetic hip and the surrounding bone were excised and replaced by a matched pair of allograft components. She obtained seven years of pain free hip function before the graft showed radiographic signs of failure; it was then replaced by a new prosthetic hip.     

Recurrent anterior hip instability after a simple hip dislocation: a case report

A 35-year-old woman sustained a simple anterior hip dislocation after a fall. Initial treatment involved a closed reduction under sedation with brace immobilization. Nine months after the initial dislocation, she began having recurrent anterior hip instability (four events) requiring closed reduction under anesthesia. Secondary to the recurrent dislocations, she had a derotational subtrochanteric femoral osteotomy at an outside hospital for the anterior instability. After this procedure she sustained five additional anterior dislocations requiring closed reduction under anesthesia. After nine anterior dislocations, she had periacetabular osteotomy retroverting her acetabulum with repair of the anterior hip capsule which has successfully solved the recurrent instability. To the author's knowledge this is the first reported case of recurrent anterior hip instability treated successfully with a periacetabular osteotomy.     

髋保护器防护髋部骨折的有限元建模与分析

[目的]通过建立带软组织的骨盆和加穿髋保护器骨盆的三维有限元模型,并模拟髋部以正侧方跌倒触地时的动作,分析跌倒过程中髋部各部位的应力、应变和位移分布,验证髋保护器防护髋部骨折的有效性。[方法]以中国力学可视人原始资料为依据,应用Abaqus 6.51软件构建带软组织的正常骨盆和佩戴髋保护器骨盆的三维有限元模型,固定约束地面刚体,对整个骨盆模型加载2 m/s的速度载荷,程序运算后观测骨盆模型佩戴髋保护器前后的应力应变及其随时间变化规律和分布云图。[结果]与没有佩戴髋保护器比较,跌倒过程中骨盆与地面的接触力、骨盆与地面产生最大接触力时松质骨最大压缩应变、大转子以及股骨颈周围应变最大值、大转子和股骨颈附近的最大Von-Mises应力值、大转子和股骨颈处的平均应力值等均明显变小。[结论]髋保护器能有效降低人体跌倒时转子间骨折的发生率,研究结果可成为其进入临床应用的生物力学依据。     

Reconstructed hip joint architecture with a standard hip arthroplasty with a unique declined offset

Possible advantages of the architectural restoration of the hip joint after total hip arthroplasty (THA) are numerous. The relationship between the femoral offset (FO) and the abductor moment arm and the polyethylene wear, loosening, instability, persistent limp due to gluteus medius insufficiency, even dislocation, leg length discrepancy have been reported [1–4]. Architectural and mechanical hip restoration has to be technically easy, reproducible and transmissible. Controversies continue: standard implants or implants with specific offset, variety of series or modular device. We study the influence of using a standard stem series with a progressive unique offset on the hip geometry.     

Revision total hip arthroplasty using a cementless modular femoral hip design

The difficulty in selecting the "ideal" components for revision total hip arthroplasty is one factor leading to poor outcomes. For femoral hip components, loosening rates of femoral revision have been reported with different types of designs. Because of improved rates with more porous components, the use of cementless femoral revision is highly attractive. This article describes a cementless femoral revision component, the ZMR system, which addresses the challenges and design goals of revision as well as surgical philosophy: off-the-shelf flexibility, proximal-distal extensive fixation, restoration of kinematics (offset, let lengths, anteversion, and muscle tensioning), and implant integrity.     

Conversion of the arthrodesed hip to a total hip arthroplasty.

Total hip arthroplasty was done in thirty-three patients who had had previous surgical attempts at arthrodesis of the hip. The arthrodesis had failed in nineteen patients, and the other fourteen patients had fused hips with symptoms in the knee and lower back. Thirty-one of the patients had satisfactory functional ability after total hip arthroplasty after one to three and one-half years' follow-up. The two patients in whom the procedure failed had complicating infections.     

Biomechanical reconstruction of the hip: a randomised study comparing total hip resurfacing and total hip arthroplasty

We have compared the biomechanical nature of the reconstruction of the hip in conventional total hip arthroplasty (THA) and surface replacement arthroplasty (SRA) in a randomised study involving 120 patients undergoing unilateral primary hip replacement. The contralateral hip was used as a control. Post-operatively, the femoral offset was significantly increased with THA (mean 5.1 mm; -2.8 to 11.6) and decreased with SRA (mean -3.3 mm; -8.9 to 8.2). Femoral offset was restored within sd 4 mm in 14 (25%) of those with THA and in 28 (57%) of the patients receiving SRA (p < 0.001). In the THA group, the leg was lengthened by a mean of 2.6 mm (-6.04 to +12.9), whereas it was shortened by a mean of 1.9 mm (-7.1 to +2.05) in the SRA group, compared with the contralateral side. Leg-length inequality was restored within sd 4 mm in 42 (86%) of the SRA and 33 (60%) of the THA patients. The radiological parameters of acetabular reconstruction were similar in both groups. Restoration of the normal proximal femoral anatomy was more precise with SRA. The enhanced stability afforded by the use of a large-diameter femoral head avoided over-lengthening of the limb or increased offset to improve soft-tissue tension as occurs sometimes in THA. In a subgroup of patients with significant pre-operative deformity, restoration of the normal hip anatomy with lower pre-operative femoral offset or significant shortening of the leg was still possible with SRA.     

Bipolar hip arthroplasty as a salvage treatment for instability of the hip

BACKGROUND: Recurrent instability of the hip in the absence of an identifiable cause is a challenging problem. It has been proposed that bipolar hip arthroplasty may have a role in the treatment of these complex cases. The purpose of our study was to evaluate the results of bipolar hip arthroplasty for the treatment of recurrent instability of the hip in a series of patients at our institution. METHODS: We reviewed the records of twenty-seven patients who had undergone bipolar hip arthroplasty as a salvage procedure for the treatment of recurrent instability of the hip after total hip replacement. All patients had undergone at least two, and a mean of three, stabilizing operative procedures on the hip prior to the bipolar arthroplasty. The mean duration of follow-up was five years (range, two to twelve years), with no patient lost to follow-up. There were six deaths, of unrelated causes. RESULTS: Bipolar arthroplasty prevented redislocation in twenty-two hips (81 percent). At the time of final follow-up, twenty-five patients (93 percent) had a stable hip. Five patients (19 percent) had had episodes of subluxation or dislocation following the bipolar arthroplasty. Two of these patients had only a single episode of dislocation that was treated successfully by immobilization. Two of the remaining three patients required a reoperation because of the instability. The hip was stabilized with the use of a constrained cup prosthesis in one of these patients, and the other patient eventually required resection arthroplasty. The third patient had continuing instability but improved function and pain relief, and a reoperation was not performed. There were a total of seven reoperations; these included revision because of disassembly of the cup in one hip, revision bipolar arthroplasty because of continuing instability in two, resection arthroplasty because of deep infection in two, revision arthroplasty because of recalcitrant groin pain in one, and revision arthroplasty because of deep infection and superior migration of the implant in one. The Harris hip score improved significantly, from a mean of 24 points (range, 5 to 45 points) preoperatively to a mean of 55 points (range, 35 to 80 points) postoperatively (p < 0.05). CONCLUSIONS: We believe that, despite some potential problems, bipolar hip arthroplasty can have a role in the salvage management of recurrent instability of the hip in patients in whom other stabilization procedures have failed.     

Revision hip arthroplasty in a patient with a hip rotationplasty (type B III b)

We report for the first time a patient who underwent a revision hip arthroplasty after a hip rotationplasty (Winkelmann type B III b) because of a chondrosarcoma in 1988. The clinical symptoms and radiographic findings (X-ray, bone scintigraphy, arthrography) of the aseptic loosening of the acetabular component are presented in detail. Furthermore, we present the functional results after hip revision.     

Developmental hip dysplasia treated with total hip arthroplasty with a straight stem and a threaded cup

BACKGROUND: Operative strategies to overcome the anatomical anomalies in patients with osteoarthritis secondary to developmental dysplasia of the hip remain controversial. The objective of this study was to determine the outcomes of total hip replacement with a grit-blasted cementless threaded cup and a cementless straight stem in patients with developmental dysplasia. METHODS: Ninety-three patients with developmental hip dysplasia who had been treated with a total of 121 cementless total hip arthroplasties were clinically assessed at a mean of 9.3 years. The acetabular reconstruction was done with a cementless threaded cup, which was medialized to ensure that at least one thread was anchored in the bone in order to achieve good primary stability. All radiographs were analyzed retrospectively. RESULTS: Kaplan-Meier survivorship analysis, with radiographic evidence of aseptic loosening as the end point, predicted a survival rate of 97.5% for the acetabular component and 100% for the femoral stem at 9.3 years. The average Harris hip score for the unrevised hips improved from 34.0 points preoperatively to 84.1 points at the latest follow-up evaluation. The average total volume of polyethylene wear at the time of final follow-up was 73.6 mm(3). CONCLUSIONS: These wear and loosening rates demonstrate that very good results were achieved in this relatively young patient population when the hip joint center had been properly restored, even when a small cup with a thin polyethylene liner had been used.     

Arthrosynovial cyst of the hip after total hip arthroplasty with a ceramic-on-ceramic interface

An inguinal arthrosynovial cyst of the hip joint developed after total hip arthroplasty leading to compression of the femoral vein. This complication occurred after implantation of a non-cemented prosthesis with a ceramic-on-ceramic interface inserted in a polyethylene sandwich. Multiple foreign bodies composed of both ceramic and polyethylene particles were visualized microscopically. Later, rupture of the joint interface required implant replacement. This cyst was a precursor sign of a deteriorating prosthesis surface.     

Outcome following a second hip fracture

Hip fracture has a significant impact on medical resources and patient morbidity and mortality. Few patients admitted with a hip fracture are considered for prophylactic measures aimed at the reduction of further fracture risk. Currently, 10-13% of patients will later sustain a second hip fracture. In considering the possible role of prophylactic measures in the prevention of second hip fracture, we investigated whether second hip fracture has a significant further impact on patients' mobility and social independence. We also sought to identify a pattern to second hip fracture that may allow targeting of those patients who are most likely to benefit from currently available prophylactic measures. We undertook a retrospective review of 49 consecutive patients admitted with a second hip fracture between August 1999 and September 2000. Fewer patients maintained their ability to walk independently after the second fracture than did so after the first (53 and 91% respectively, P<0.0005). Following second hip fracture, patients' level of mobility determined their future social independence. Older patients and those with a history of multiple falls had a shorter time interval between fractures. Second hip fracture has a significant further impact on patients' mobility and social independence. Younger patients and those without a history of multiple falls are most likely to benefit from medical prophylaxis.     

Outcome of revision hip arthroplasty in patients with a previous total hip replacement for developmental dysplasia of the hip

Our aim was to determine if the height of the cup, lateralisation or the abduction angle correlated with functional outcome or survivorship in revision total hip replacement in patients with a previous diagnosis of developmental dysplasia of the hip. A retrospective investigation of 51 patients (63 hips) who had undergone revision total hip replacement was performed. The mean duration of follow-up was 119 months. Forty-one patients (52 hips) were available for both determination of functional outcome and survivorship analysis. Ten patients (11 hips) were only available for survivorship analysis.The height of the cup was found to have a statistically significant correlation with functional outcome and a high hip centre correlated with a worse outcome score. Patients with a hip centre of less than 3.5 cm above the anatomical level had a statistically better survivorship of the cup than those with centres higher than this. Restoration of the height of the centre of the hip to as near the anatomical position as possible improved functional outcome and survivorship of the cup.