Removal of trabecular metal osteonecrosis intervention implant and conversion to primary total hip arthroplasty

Core decompression and placement of the Trabecular Metal Osteonecrosis Intervention Implant have shown to be initially successful in treating early osteonecrosis. When treatment fails, however, patients often undergo primary total hip arthroplasty (THA) requiring removal of a previously inserted trabecular metal implant. We describe a technical tip for removal of a well-ingrown trabecular metal screw. A metal-cutting trephine placed over the screw allows for removal in an efficient manner while minimizing additional dissection and bone loss during conversion to THA.     

Femoral component neck fracture after failed hip resurfacing arthroplasty

Failure on the femoral side after third-generation metal-on-metal hip resurfacing arthroplasty is suggested to be easily treated with conversion to conventional total hip arthroplasty. Clinical results of conversion for failed hip resurfacing arthroplasty with the use of primary femoral implants confirmed this for a short-term follow-up. We present a case of the occurrence of a stemmed femoral implant neck fracture in a patient who was earlier treated for a failed hip resurfacing. We advise to consider acetabular revision in case of (suspected) acetabular metal damage and to use a stem component with a relative large neck diameter.     

Bipolar versus total hip arthroplasty for hip osteonecrosis in the same patient

The authors studied 28 patients with bilateral avascular necrosis of the femoral head who were treated with a cementless bipolar endoprosthesis in one hip and cementless total hip arthroplasty in the other. All the hips selected for bipolar endoprostheses were classified as having avascular necrosis of the femoral head Ficat Stage III, and all the hips selected for total hip arthroplasty were classified as having Ficat Stage IV avascular necrosis. After a midterm followup of an average of 6.4 years (range, 4-12 years), 24 of 28 hips that received bipolar endoprostheses were considered satisfactory, whereas 23 of 28 hips in which an arthroplasty was done were considered satisfactory. After a followup of more than 6 years, the cartilaginous space of the acetabulum could be preserved in 25 hips (89.3%) that received a bipolar endoprosthesis. There were no statistical differences in both groups in terms of clinical result, thigh pain, groin pain, osteolysis, dislocation, and revision rate. Total hip arthroplasty is not the preferred treatment for all patients with hip osteonecrosis. In young patients with Ficat Stage III osteonecrosis with Grade 0 or Grade I cartilage, the use of a cementless bipolar endoprosthesis with a bone ingrowth stem may be considered as an alternative to total hip arthroplasty.     

Cementless hip arthroplasty in the treatment of patients with femoral head necrosis

Treatment of patients with osteonecrosis of the femoral head focuses on pain relief and improved function of the hip. Total hip arthroplasty remains an effective tool for the treatment of patients with end-stage osteonecrosis with collapse of the femoral head, although there is a greater risk for failure. The aim of the current study was to assess the long-term survival of cementless total hip arthroplasties in 28 patients (36 hips) with osteonecrosis of the femoral head (Steinberg Stage V and Stage VI) with an average followup of 11.2 years (range, 10-15 years). There were 19 women and nine men with an average age of 51.4 years (range, 28-65 years). A threaded titanium cup CST (Conical Screwed Titanium) was used in all patients and different cementless femoral components were used depending on the optimal fit in the femoral canal as assessed during preoperative templating. No serious complications were encountered postoperatively. The patients were evaluated preoperatively and postoperatively with the Merle d'Aubigné and Postel scale. After cementless total hip arthroplasty, the average pain score improved 3.6 points, walking ability improved 1.6 points, and range of motion improved 1 point. Two patients had thigh pain. Radiographic evaluation on anteroposterior and lateral radiographs of the proximal femur was excellent in 10 hips postoperatively. No heterotropic ossification was observed, although proximal femoral atrophy was seen in 15 hips. Clinical and radiologic findings did not correlate. There were two revisions of the acetabular implants in one patient with bilateral idiopathic osteonecroses and total hip replacement. Overall, survival of the prostheses was 93.4% at the average followup of 11.2 years.     

Salvage of failed treatment of hip fractures

Typically, patients with failed internal fixation of a hip fracture have marked pain and disability. These patients may present treatment challenges. Salvage is tailored to the anatomic site of the nonunion, the quality of the remaining bone and articular surface, and patient factors such as age and activity level. In younger patients with either a femoral neck or intertrochanteric fracture nonunion with a satisfactory hip joint, treatment typically involves revision internal fixation with or without osteotomy or bone grafting. In older patients with poor remaining proximal bone stock or a badly damaged hip joint, conversion to hip arthroplasty can restore function effectively and reduce pain. For femoral head salvage procedures, choosing a fixation device and accurate preoperative planning are the major challenges in decision making. For conversion to arthroplasty, the major challenges are assessing the need for acetabular resurfacing, selecting the femoral implant, and managing the greater trochanter. Technical challenges include broken hardware, deformity, and femoral bone defects. Attention to technical details can minimize potential complications.     

Gaucher disease — the orthopaedic aspect

Seven patients with Gaucher type 1 disease are presented: five female and two male. The orthopaedic problems encountered were: avascular necrosis of both femoral heads in two girls, bilateral bone infarctions of the femurs in all three girls, complicated by staphylococcal osteomyelitis of the right femur in one girl and by pathological fractures of both femurs in another girl, osteonecrosis of both humeral heads in one male adult patient, osteonecrosis of the femoral heads in two further adults (male and female), and a pathological fracture of the fourth lumbar vertebra in another adult woman with concomitant humeral head involvement. The patient with osteonecrosis of the humeral head was treated with a total shoulder arthroplasty, and the two patients with osteonecrosis of the femoral heads were treated with total hip arthroplasties, with satisfactory intermediate and long-term results.     

The extent of osteocyte death in the proximal femur of patients with osteonecrosis of the femoral head

Our aim was to assess the local extent of osteocyte death in the proximal femur of 16 patients with osteonecrosis of the femoral head. We performed histological examination of the femoral heads and cancellous bone biopsies from four regions of the proximal femur in patients undergoing total hip arthroplasty. A control group consisted of 19 patients with osteoarthritis. All histological specimens were examined in a blinded fashion. Extensive osteonecrosis was shown in the proximal femur up to 4 cm below the lesser trochanter in the group with osteonecrosis. There was an overall statistically significant difference in the extent of osteocyte death distal to the femoral head between the two groups (p < 0.001). We discuss the implications of these findings as possible contributing factors in regard to the early failure of total hip arthroplasty reported in patients with osteonecrosis of the femoral head.     

Hemi-arthroplasty with supplemental fixation of greater trochanter to treat failed hip screws of femoral intertrochanteric fracture

INTRODUCTION: Management for failed hip screw after femoral intertrochanteric fracture is a challenge for orthopaedic surgeons. The unfavorable factors include severe osteoporosis, unstable fracture geometry, improper placement of hip screw, and repeated trauma. Except revision fixation of the fractures, arthroplasty may be indicated in case of destructed femoral head. In this study, we reported the surgical outcomes of patients with concomitant failed hip screws and fractures of greater trochanter operated by hemi-arthroplasties. MATERIALS AND METHODS: We treated 16 patients of failed hip screws with concomitant fracture of greater trochanter surgically by hemi-arthroplasty and cable-grip system from January 2001 to December 2004. The reattachment of greater trochanter by cable-grip system enhanced abductor mechanism to reduce the dislocation rate of hip arthroplasty. The hemi-arthroplasties eliminated the pain from the destructed femoral head. Partial weight bearing was allowed postoperatively. The patients were followed every 6 weeks clinically and radiologically. Full weight bearing was not allowed until solid bony union was seen on the plain radiographs. RESULTS: Among these 16 patients, all patients achieved solid union of greater trochanter except one by 24 weeks postoperatively. No postoperative wound infection was found. No dislocation of hemi-arthroplasty occurred during the postoperative follow-up. The clinical assessment based on SF-36 questionnaire improved from 41.9 to 82.7. CONCLUSION: Hemi-arthroplasty with supplemental fixation of greater trochanter is a rational option to treat failed hip screws with fracture of greater trochanter in case of destructed femoral head.     

Component removal in revision total hip arthroplasty.

One of the primary steps in revision hip arthroplasty is the extraction of retained components before surgical reconstruction. In revision arthroplasty, the removal of well-fixed components and cement can be extremely demanding, time consuming, and damaging to the remaining host bone. The aims of the current study were to examine the numerous operative techniques used during extraction of acetabular and femoral components and review the results of revision hip arthroplasty after cementless component removal. A review of 157 acetabular components and 113 femoral components removed from 219 patients during hip revision arthroplasty between 1985 and 2000 was done. The average age of the patients was 64.3 years. The average followup was 5 years (range, 0.7-12.5 years). An extended proximal femoral osteotomy was done in 37 (33%) of the femoral revisions. There were 14 (5%) acetabular failures for which the patients required reoperation. There were no femoral rerevisions. Complications included dislocation (6% after acetabular revision and 9% after femoral revision), infection (6%), femoral fracture (6%), hematoma (3.5%), acetabular fixation failure (2.5%), and femoral osteolysis (1%). The removal of cemented and well-fixed porous-coated implants can be done with adequate preoperative planning and a thorough knowledge of numerous implant removal techniques.     

Early results of prosthetic hip replacement for femoral neck fracture in active elderly patients

PURPOSE: To evaluate the short-term clinical and functional outcomes of total hip arthroplasty performed for physiologically active elderly patients with Garden type-3 or -4 femoral neck fracture. METHODS: Records of 47 consecutive patients (40 female, 7 male) with type-3 or -4 femoral neck fracture (Garden classification) who underwent cemented total hip arthroplasty at our hospital during January 1999 to December 2002 were reviewed. Radiological and clinical (Harris functional hip score and Oxford hip score) assessments of 38 patients were measured with a mean follow-up period of 21 months (range, 4-48 months). RESULTS: The mean age of the 47 patients was 75 years (range, 62-89 years). Records of 9 patients were excluded because of death, lost to follow-up, and development of deep infection that necessitated implant removal and excision arthroplasty. The mean Harris hip score of the 38 patients was 83 (range, 59-97), whereas the mean Oxford hip score was 25.2 (range, 14-33). Pain in the hips was absent in 30 patients, 6 had slight pain occasionally, and 2 patients had mild-to-moderate hip discomfort. No signs of aseptic loosening or change in implant position were noted on radiographic assessment. Two cases of dislocation were reduced by closed reduction. Two patients had deep wound infection and were treated with debridement, implant removal, and conversion to girdle stone. CONCLUSION: This short-term study showed that total hip arthroplasty for femoral neck fracture had good postoperative results in functional hip and pain scores. More attention should be paid to coexisting medical illness (e.g. diabetes mellitus, hypertension, and ischaemic heart disease) and prevention of infection.     

Outcome of hemiresurfacing in osteonecrosis of the femoral head

Hemiresurfacing of the femoral head for treatment of osteonecrosis has been proposed as a reasonable alternative to total hip arthroplasty. The results of 59 patients with Ficat Stage III osteonecrosis done by a single surgeon are reviewed. At an average followup of 4.5 years, 16 patients were considered failures because of conversion to total hip arthroplasty or considerable groin pain requiring medication. Failure did not correlate with age, body mass index, preoperative length of symptoms, acetabular articular cartilage status at the time of surgery, or cause of the underlying disease. The only factor associated with failure was a lower preoperative Harris hip score. Conversion of the failed implants to total hip arthroplasty was straightforward, confirming the conservative nature of the procedure. However, pain relief and recovery after resurfacing are less reliable than that associated with total hip arthroplasty. This procedure may be appropriate for patients younger than 30 years, given the ease of conversion to THR if failure occurs. The patient should be counseled regarding expectations.     

Total hip arthroplasty in patients with proximal femoral deformity

Most proximal femoral deformities encountered during hip arthroplasty are secondary to developmental processes, previous osteotomy, or fracture. A classification method is proposed in which deformities are categorized anatomically by level. Anatomic deformity levels include: greater trochanteric deformities, femoral neck deformities, metaphyseal level deformities, and diaphyseal level deformities. Deformities at each level may be angular, rotational or translational, abnormal bone size, or a combination thereof. Treatment is individualized according to patient needs and the anatomy of the deformity. Careful preoperative planning helps predict prosthesis requirements and technical challenges. If cemented implants are used, care must be taken to obtain reasonable alignment and a continuous cement mantle. For uncemented implants, obtaining a good fit is challenging and there is a risk of intraoperative fracture. Access to a wide range of implants helps the surgeon treat unique femoral geometries. Implants fixed in the diaphysis allow some proximal femoral deformities to be bypassed. Modular or custom implants simplify treatment of certain deformities. For patients with severe deformities, femoral osteotomy may be required. Successful osteotomy requires correcting the deformity, maintaining vascular supply of fragments, obtaining fixation of osteotomy fragments (with the implant or adjunctive fixation), and obtaining implant stability. Although most deformities can be treated during hip arthroplasty, occasionally there is a role for two-stage treatment: deformity correction followed later by arthroplasty.     

Lack of radiographic loosening signs in a hip resurfacing that failed by stem fracture

Fracture of the femoral stem is a rare manifestation of femoral component loosening in hip resurfacing. The patient had undergone successful hip resurfacing 3 years prior to presentation, presenting with complaints of groin pain, but without radiographic evidence of loosening. At 6 years post-operatively, the patient again presented with groin pain. Radiographs demonstrated a mid-stem fracture. Analysis of the retrieved implant and resected femoral head following conversion to total hip arthroplasty indicated that component failure and fracture appeared to be secondary to failed fixation and implant loosening not related to osteonecrosis or acute femoral neck fracture. The case report highlights the difficulty in diagnosing femoral component loosening in hip resurfacing in the absence of gross implant subsidence or stem radiolucency.     

Metal-on-metal surface replacement: a triumph of hope over reason: opposes

Hip resurfacing has been performed for over a decade but still raises controversy as an alternative to traditional total hip arthroplasty (THA). Concerns exist about the potential complications of hip resurfacing, including femoral neck fracture and osteonecrosis of the femoral head. Recently, attention has been given to the metal-on-metal bearing of hip resurfacing with regard to production of metal ions, possible tissue necrosis, and rare instances of metal hypersensitivity. Given the success of the gold-standard THA, it is understandable why some surgeons believe metal-on-metal surface replacement to be "a triumph of hope over reason." However, this article opposes that viewpoint, demonstrating that data exist to justify the practice of preserving bone in younger patients. Hip resurfacing can maintain femoral bone without the expense of removing additional acetabular bone by using modern implants with incremental sizing. Furthermore, many of the problems cited with the bearing couple (such as excess metal production) have been due to poor implant designs, which have now been removed from the market. Finally, we now realize that the metal-on-metal articulation is more sensitive to malposition; thus, good surgical technique and experience can solve many of the problems that have been cited in the past. National registry results confirm that in a select population, hip resurfacing performs comparably to THA, while fulfilling the goal of bone preservation.     

A new mode of clinical failure of porous tantalum rod

The area of osteonecrosis of the head of femur affected by the disease process varies from a small localized lesion to a global lesion. Without specific treatment 80% of the clinically diagnosed cases will progress, and most will eventually require arthroplasty. Therefore the goal is to diagnose and treat the condition in the earliest stage. A number of surgical procedures have been described to retard or prevent progression of the disease and to preserve the femoral head. An implant made of porous tantalum has been developed to function as a structural graft to provide mechanical support to the subchondral plate of the necrotic femoral head, and possibly allow bone growth into the avascular region. Porous tantalum implant failure with associated radiological progression of the disease is reported in the literature; however, there is no report of clinical failure of the implant without radiological progression of the disease. We report a case of clinical failure of porous tantalum implant, seven months after surgery without any radiological progression of the disease, and with histopathological evidence of new bone formation around the porous tantalum implant. The patient was succesfully treated by total hip arthroplasty.     

Mechanical evaluation of cadaver retrieval specimens of cementless bone-ingrown total hip arthroplasty femoral components

Early retrieval prior to gross failure of implants can provide valuable information for critical issues in total joint arthroplasty. To evaluate fixation of the femoral component in total hip arthroplasty, two femoral specimens—one Mallory-Head (Biomet, Warsaw, IN) specimen and one AML (DePuy, Warsaw, IN) specimen—were retrieved after 2–8 years of successful use in active patients. Radiographs were made and evaluated for trabecular apposition to the porous-coated areas of the stem, then torsional and axial load tests were performed for each specimen to determine micromotion and displacement at the bone-implant interface. Both implants had radiographic signs of bone ingrowth. No permanent rotational displacement was found in either specimen during torsional load testing, but rotational and axial micromotion were found in both. These findings indicate excellent fixation of implant to bone, and no slippage at the bone-implant interface. The Mallory-Head implant had much greater elastic displacement than the AML, and histological examination showed cancellous bone ingrowth into the porous-coated portion of the Mallory-Head stem. The AML implant, which withstood much higher torsional loads, was found upon histological evaluation to have dense cortical-cancellous bone ingrowth. Strength of attachment of the metal implant to bone was good in both specimens, and neither had slippage at this interface. Differences in mechanical behavior can be attributed to the type of bone supporting the implant. The Mallory-Head implant had a severely worn titanium femoral head, so the joint was full of particulate metal debris. Particle migration appeared to be especially well controlled by the closed-pore type of porous coating of the Mallory-Head stem. Since the AML implant had a cobalt-chromium femoral head, and consequently had no detectable metallic wear debris, a comparison of the barrier effect of the two types of porous coating could not be made. The beaded porous surface of the AML femoral component also seemed to be a barrier to polyethylene particle migration. Osteolysis was not found around either implant, and neither implant appeared to be clinically affected by particulate debris despite long-term service.     

Early failures of porous tantalum osteonecrosis implants: a case series with retrieval analysis

Backgrounds

Porous tantalum osteonecrosis implants have been used in femoral head necrosis for several years, while the clinical outcomes were mixed. As a joint-preserving surgery, early necrosis deterioration and conversion to total hip arthroplasy failed our expectation. We hence investigate an observational study with retrieval analysis to find out the underlying reasons.

Methods

Thirteen patients were treated with core decompression and implantation of a tantalum rod. The cases were evaluated both functionally and radiologically. We retrieved and analyzed the micro-structural changes and the histopathologic features of four early failed femoral heads with scanning electron microscopy, histopathologic examination, and micro-CT scaning.

Results

All implants were placed in proper positions. One-year survival rate was 64.29 % with a HSS score of 81.11?±?15.62. Four patients converted to arthroplasty in a mean time of 305 days (0.84 years), with a HSS score of 43.75?±?7.5 at the last follow-up. A liquid layer surrounded the tantalum implant was noted on MRI in all four failed cases. Volume render CT remodeling revealed interspace between the metal and bone. Scanning electron microscopy and histopathologic examination indicated sparse and isolated bone ingrowth into the implants. The remodeled trabecular bone and the increased density around the peri-implant area were illustrated with micro-CT scaning.

Conclusions

The deterioration of early failed tantalum implant exceeds the nature of osteonecrosis progression. Rather than insufficient mechanical support resulting in improper position and invalid bone ingrowth, nullification of core decompression and consequential intra-osseous pressurization probably led to early failure of porous tantalum osteonecrosis implants.

     

Extensively porous-coated femoral stems in revision hip arthroplasty: rationale and results

Optimal outcomes of revision femoral arthroplasty include achieving rotational stability of the revision implant, preventing axial migration of the implant to obtain stability, and reproducing normal hip biomechanics. Cemented and proximally porous-coated implants are not well-suited to achieving these goals in the presence of metaphyseal bone defects and poor endosteal cement bonding. Extensively porous-coated implants are more likely to achieve these goals if the selection of the implant is appropriate for each defect encountered and if technical problems can be identified that may arise during canal preparation andcomponent insertion. The selection of curved implants for longer revisions may help avoid complications.     

Partial resurfacing arthroplasty of the femoral head in avascular necrosis. Methods, indications, and results

The current study reports results using a partial surface replacement for osteonecrosis of the femoral head. The surgical technique, implant design, and instrumentation cause minor soft tissue disruption and require little bony resection. Thirty-seven prostheses were placed in 33 patients during the past 7 years. The mean age of the patients was 43 years (range, 24-59 years), and the preoperative Ficat classification was Stage III in 26 hips, Stage IV in 10, and Stage II in one hip. For the surviving prostheses, the mean followup was 49 months (range, 24-89 months). Of the 28 surviving implants, 24 continue to function well and the patients have excellent or good hip scores according to the Merle d'Aubigne system. There were nine failures, mainly attributable to the extension of the osteonecrosis. In comparison with alternative techniques, the operative surgery for partial surface replacement is straightforward, requiring little preoperative planning and immediate weightbearing postoperatively. Should failure occur, little bone stock loss is incurred and revision to a total hip replacement is as simple as primary hip arthroplasty.