Total Hip Prosthesis Research Articles

Revision arthroplasty with a hip-inspired computer-assisted design/computer-assisted manufacturing implant for glenoid-deficient shoulders

Revision arthroplasty for failed post-traumatic humeral head replacement associated with rotator cuff and glenoid deficiency is challenging. Current surgical solutions are fraught with complications, and no best-practice strategy has been established. We hypothesized that the computer-assisted design/computer-assisted manufacturing (CAD/CAM) shoulder (Stanmore Implants, Elstree, UK), a total shoulder design resembling a total hip prosthesis, can offer a reliable alternative in this surgically challenging subset of patients with rotator cuff deficiency and advanced glenoid bone loss. Twenty-one patients with failed post-traumatic humeral head replacement associated with rotator cuff and glenoid deficiency underwent revision with CAD/CAM shoulders between 2005 and 2010. Clinical data were collected prospectively and analyzed at a mean follow-up of 3 years. After revision, the pain rating at rest (on a 0-10 numerical scale) decreased from 5.6 ± 1.3 to 1.1 ± 1.3 (P < .001) and pain during activity decreased from 7.4 ± 1.2 to 2.1 ± 1.8 (P < .001). The Oxford shoulder score improved from 47 ± 6 to 31 ± 9 (P < .001), and the subjective shoulder value (on a 0%-100% scale) improved from 22% ± 14% to 45% ± 18% (P < .001). Active shoulder range of motion was similar before and after revision. Postoperative complications occurred in 9 patients and included 1 infection, 2 periprosthetic fractures, 2 prosthetic dislocations, and 4 fixation screw fractures. No case of glenoid loosening occurred. The CAD/CAM shoulder offers a reliable method of securing a glenoid component in shoulders with advanced glenoid deficiency and should be considered as an alternative to other surgical methods in these challenging cases. At 3 years' follow-up, pain and clinical scores improved significantly and no case of glenoid loosening occurred.

Response to comment on Brunnekreef et al.: Is etoricoxib effective in preventing heterotopic ossification after primary total hip arthroplasty?

1. We do not believe that differences in operative skills would have influenced our outcome. All 42 patients were operated upon by two senior orthopaedic staff members. One operated on 25 hips with his team and the other operated on 17 hips. Both orthopaedic surgeons have extensive orthopaedic skills and have been working together for many years in hip surgery. We believe their operative skills are comparable. We are not aware of studies that have reported the influence of surgical skills on the heterotopic ossification rate after total hip prostheses. 2. From previous studies on this topic we have not seen heterotopic ossifications that occurred in the interval between six and 12 months. There may, in rare cases, be some progression of the extension of the heterotopic ossification after six months, however this is very unlikely. Therefore, we think six months follow-up is sufficient. 3. The radiological assessment was done by one independent radiologist. The radiologist is an highly qualified radiologist, who is specialised in the assessment of orthopaedic images. Possibly it would have been better to use two radiologists, we will take your recommendation for future studies. 4. We totally agree with your comment. In our hospital we have standardised AP pelvic photographs. 5. We agree with the author that future large scale patient and control research is needed to further study the positive effect of a COX-2 inhibitor in the prevention of heterotopic ossifications. Indeed, a previous study on the effect of rofecoxib investigated using both a small pilot study [1] and a large randomised controlled trial [2]. The dose and time administration of COX-2 inhibitors is an interesting research suggestion.

Long-term survival of the uncemented Balgrist total hip replacement cup

The purpose of this study was to evaluate the long-term clinical and radiographic outcomes of the Balgrist total hip replacement cup. We report the results of a retrospective review of 195 total hip prostheses with Balgrist cup implanted in 178 patients. There were 59 men and 119 women with a mean age at surgery of 52.3 years (range, 19-72). Cox regression was used to determine the influence of independent variables on the survivorship of the prosthesis. There were 117 (66 %) of 178 patients, and 131 (67 %) of 195 hips available for assessment at a mean follow-up of 17.4 years. A total of 21 patients (22 hips) were lost from follow-up (12 %). A total of 25 patients (27 hips) required some type of re-operation during the follow-up period. Eight of 27 re-operations (30 %) were directly caused by the Balgrist cup failure due to fatigue fracture of the metallic shell (n = 5; 19 %), polyethylene wear (n = 2; 7 %) and aseptic loosening (n = 1; 4 %). The mean polyethylene wear rate was 0.068 mm/year (range, 0.008-0.230; SD = 0.043). The risk of re-operation for any reason was decreased with dysplastic hip as a primary diagnosis (hazard ratio; HR = 0.250; 95 % CI 0.086-0.725) and with greater age at the time of surgery (HR = 0.923; 95 % CI 0.880-0.969). The 19-year survivorship with re-operation for any reason was 75.6 % (95 % CI 67.0-84.2). The 19-year survivorship with re-operation for the Balgrist cup failure was 90.5 % (95 % CI 83.4-97.6). The Balgrist cup continues to provide excellent clinical and radiological outcomes. This is associated at least in part with a low polyethylene wear rate. The main reason for the Balgrist cup failure is fatigue fracture of the metallic shell.

AB0959 Radiological and clinical profil of osteoarthritic patients undergoing total joint replacement

BackgroundOsteoarthritis is a major burden worldwide.ObjectivesArthritic conditions are extremely painful for the patient and are associated with a significant reduction in health related quality of life (HRQOL), mainly in term...

AB0360 Results of total hip prosthesis in patients with rheumatoid arthritis according to the received therapy

BackgroundTotal hip prosthesis is an effective method of relieving pain and improving function the hip in patients with rheumatoid arthritis (RA). Topical drug therapy remains the question of RA therapy...

Mechanical Evaluation of Adjunctive Fixation for Prevention of Periprosthetic Femur Fracture With the Zurich Cementless Total Hip Prosthesis

To evaluate whether cerclage wire or a lateral plate increases the peak-torque load to failure, compared to femora without adjunctive fixation, in femora implanted with Zurich Cementless stems. In vitro biomechanical study. Paired femora from adult dogs (n = 24) weighing 28-35 kg. Pairs of femora were implanted with a stem and randomly assigned to 2 treatment groups: cerclage or plate. Within each pair, either 3 loop cerclage wires or a laterally applied 12-hole Advanced Locking Plate System 10-mm plate (ALPS 10) were implanted in a femur, whereas the contralateral femur acted as control with no adjunctive fixation. After application of a static axial load each specimen was loaded to failure in torsion. Peak torque load at failure was compared between femora with each adjunctive fixation and the control using a paired t-test; P < .05 was considered significant. In both treatment groups, femora with adjunctive fixation failed at higher loads compared to the femora without fixation; however, significant difference in peak torque at failure between treated femora and control was found only in the plated group (P < .05). Femora implanted with plates and with cerclage were 13.9% and 7.2% stronger in torsion than the femora without fixation, respectively. Adjunctive fixation with a laterally applied ALPS 10 may aid in the prevention of peri-prosthetic fractures associated with Zurich Cementless medium stems.

Septic Prepatellar Bursitis Caused by Traumatic Inoculation of Nocardia Nova: Case Report and Literature Review.

The Nocardia species belongs to the Actinomycetaceae family, and it typically appears as delicate, branching, and filamentous gram-positive rods. Because of the uncommon nature of Nocardia infections, very few cases of musculoskeletal infections caused by the Nocardia species have been reported1. One case reported Nocardia nova infection of a total hip prosthesis in a patient who had a severe case of systemic lupus erythematosus2, and another report described cutaneous nocardiosis that led to sepsis following a total knee replacement1. In this paper, we report an unusual case of septic prepatellar bursitis caused by Nocardia nova following a traumatic injury. Since the mechanism of injury in this case report is so universally common, the importance of this report is twofold: first, to alert orthopaedic surgeons to include Nocardia species on a differential list of bacterial pathogens, and second, to suggest consideration that culture results be followed for an extended period to assist in the identification of atypical pathogens when diagnosing musculoskeletal infections. The patient was informed that data concerning the case would be submitted for publication, and she provided consent. A forty-nine-year-old woman presented to her primary medical physician with a prepatellar bursal effusion of the right knee. The medical history included borderline diabetes, fibromyalgia, hypothyroidism, headaches, and depression, but the patient was otherwise immunocompetent. The knee effusion had originated from a fall on a sidewalk. During the fall, the patient’s knee hit the ground, and gravel and dirt got into the wound. This trauma led to swelling of the anterior part of the knee, warmth, and continuous pain upon exertion. After three days of ongoing bleeding from the wound, the patient sought medical treatment; oral cephalexin was prescribed. Because of persistent knee pain, the patient sought additional care at an urgent care center; trimethoprim/sulfamethoxazole …

Morphometric evaluation of proximal femur in patients with unilateral total hip prosthesis

It is important to know the morphometric characteristics of the proximal femur. This is necessary to reduce the risk of complications related to surgical procedures performed in the area due to vascular, metabolic, or traumatic causes. It is of importance for achieving the alignment of the prosthesis to be implanted as well. The aim of this study was to evaluate the morphometric characteristics of the proximal femur and to establish a database for making and performing total hip prosthesis. Anteroposterior (AP) pelvic radiographs of 162 cases, with a mean age of 65.6 years, who had undergone unilateral total hip arthroplasty were used in this study. Femoral head diameter (FHD), femoral neck width (FNW), femoral neck length (FNL), femoral neck axis length (FNAL), intertrochanteric line length (ILL), and neck-shaft angle (NSA) were measured on radiographs obtained digitally using setrapacs media. FHD was found to be 48.1 ± 3.7 mm, FNW 35.4 ± 4.2 mm, FNL 30.8 ± 6.1 mm, FNAL 98.6 ± 9.4 mm, ILL 81.1 ± 7.9 mm, and NSA 130.4 ± 5.1° on average. The comparison of the mean values for females and males revealed a statistically significant difference between the FHD, FNW, FNL, FNAL, and ILL (P = 0.000). There was no statistically significant difference in NSA between males and females (P = 0.356). A weak correlation was found between age and parameter values using correlation analysis (r < 0.24, P > 0.05). In morphometric assessment of the proximal femur, taking into consideration regional and sexual differences is of importance for prosthesis design and surgical success.

Is the Bone-bonding Ability of a Cementless Total Hip Prosthesis Enhanced by Alkaline and Heat Treatments?

Cementless total hip arthroplasty (THA) implants using alkaline and heat treatments were developed to enhance bone bonding. Although bone-bonding ability of the alkali- and heat-treated titanium surface has been demonstrated in animal studies, it remains unknown whether it enhances or provides durable bone bonding in humans. We therefore (1) determined long-term survivorship, function, and radiographic signs of failure of fixation of alkali- and heat-treated THA implants; and (2) histologically examined their bone-bonding ability in two human retrievals. We retrospectively reviewed 58 patients who underwent 70 primary THAs, of whom 67 were available for minimum followup of 8 years (average, 10 years; range, 8-12 years). Survival rate was calculated. Hip function was evaluated using the Japan Orthopaedic Association (JOA) hip scores, and radiographic signs of implant failure were determined from anteroposterior radiographs. Two retrieved implants were investigated histologically. Using revision for any reason as the end point, the overall survival rate was 98% (95% confidence interval, 96%-100%) at 10 years. The patients' average JOA hip scores improved from 47 points preoperatively to 91 points at the time of the last followup. No implant had radiographic signs of loosening. Histologically we observed bone in the pores 2 weeks after implantation in one specimen and apparently direct bonding between bone and the titanium surface in its deep pores 8 years after implantation. Cementless THA implants with alkaline and heat treatments showed a high survival rate. Further study is required to determine whether the treatment enhances direct bone bonding.

High failure rate of trochanteric fracture osteosynthesis with proximal femoral locking compression plate

IntroductionStable reconstruction of proximal femoral (PF) fractures is especially challenging due to the peculiarity of the injury patterns and the high load-bearing requirement. Since its introduction in 2007, the PF-locking compression plate (LCP) 4.5/5.0 has improved osteosynthesis for intertrochanteric and subtrochanteric fractures of the femur. This study reports our early results with this implant. MethodsBetween January 2008 and June 2010, 19 of 52 patients (12 males, 7 females; mean age 59 years, range 19–96 years) presenting with fractures of the trochanteric region were treated at the authors’ level 1 trauma centre with open reduction and internal fixation using PF-LCP. Postoperatively, partial weight bearing was allowed for all 19 patients. Follow-up included a thorough clinical and radiological evaluation at 1.5, 3, 6, 12, 24, 36 and 48 months. Failure analysis was based on conventional radiological and clinical assessment regarding the type of fracture, postoperative repositioning, secondary fracture dislocation in relation to the fracture constellation and postoperative clinical function (Merle d’Aubigné score). ResultsIn 18 patients surgery achieved adequate reduction and stable fixation without intra-operative complications. In one patient an ad latus displacement was observed on postoperative X-rays. At the third month follow-up four patients presented with secondary varus collapse and at the sixth month follow-up two patients had ‘cut-outs’ of the proximal fragment, with one patient having implant failure due to a broken proximal screw. Revision surgeries were performed in eight patients, one patient receiving a change of one screw, three patients undergoing reosteosynthesis with implantation of a condylar plate and one patient undergoing hardware removal with secondary implantation of a total hip prosthesis. Eight patients suffered from persistent trochanteric pain and three patients underwent hardware removal. ConclusionsEarly results for PF-LCP osteosynthesis show major complications in 7 of 19 patients requiring reosteosynthesis or prosthesis implantation due to secondary loss of reduction or hardware removal. Further studies are required to evaluate the limitations of this device.

A study of the usefulness of a periarticular multimodal drug cocktail injection for pain management after total hip arthroplasty

BackgroundMeasures for pain management after total hip arthroplasty (THA) are important for early improvement in the quality of life after operation and early postoperative rehabilitation. We investigated the analgesic effect of locally injected drugs around the total hip prosthesis. Methods54 patients undergoing THA were randomized either to receive a periarticular intraoperative injection of a 30-ml mixture containing morphine hydrochloride 10 mg, 0.5% bupivacaine 20 ml, epinephrine 0.3 mg, and saline 8.7 ml or to receive no injection. The perioperative analgesic regimen was standardized. The evaluation items included assessment of pain using a 100-point visual analog scale (VAS) after the patients awoke on the day of the operation and on postoperative day 1, the dose of diclofenac sodium suppository, the number of days for acquiring assisted ambulation with a walking cane, and side effects. ResultsThe VAS score on the day of the operation was significantly low in the injection group. No cardiac or central nervous system toxicity was observed. ConclusionsIntraoperative periarticular injection with multimodal drugs can significantly reduce pain on the day of the operation, with no apparent risks, following THA.

Case Report: Painless Chronic Liner Dissociation of a Total Hip Arthroplasty

Dislocation or liner dissociation of a total hip prosthesis usually results in pain and discomfort. Although several reports describe chronic dislocation and its treatment, chronic liner dissociation is an unreported complication. We report an unrecognized dissociation and displacement of the liner of a total hip prosthesis after revision THA. The patient had virtually no pain or functional restrictions. The patient's only complaint was pain on the contralateral side, associated with a leg-length discrepancy. Since the patient had no complaints relative to the liner dissociation we elected not to pursue further treatment. The contralateral pain was treated successfully with a shoe lift. Chronic dislocation of a THA is a rare complication and we found reports of only seven cases in the literature. We found no reports of chronic liner dissociation. Orthopaedic surgeons should be aware of the possibility of this rare complication. Our case and the literature suggest treatment can be nonsurgical or surgical.

A study of the wear performance in a hip simulator of a metal–metal Co–Cr alloy with different boron additions

There has been a widely renewed interest in the use of metal-on-metal bearings for hip arthroplasties due to the medium-term results using contemporary conventional hip replacements. However, the search for new hip joint designs is targeted at younger and more active patients to optimise the performance of the bearing couple. The aim of this study was to investigate the wear behaviour of a modified Co–Cr alloy with boron additions. For this purpose, as-cast Co–Cr cups and heads were mated with different boron additions (0, 0.3, 0.6 and 1Bwt%) and tested in 4×106 cycles using the three-axial FIME II hip joint simulator under variable load profiles, and foetal bovine serum solution was as the lubricant. The wear was measured gravimetrically throughout the test. In addition, the bearing couples were characterised with metallographic techniques, confocal microscopy, scanning electronic microscopy, energy dispersive spectroscopy and roughness and hardness tests. The results showed an increase of the hard phases and wear resistance as the boron increased. In tribological terms, the results of this study showed the potential of this novel alloy as alternative for total hip prostheses.

Comparison of ceramic‐on‐metal and metal‐on‐metal hip prostheses under adverse conditions

Ceramic-on-metal (COM) hip replacements, where the head is BIOLOX® Delta ceramic and the liner is CoCrMo alloy, have demonstrated reduced wear under standard simulator conditions compared to metal-on-metal (MOM) bearings. COM hips are now being used clinically around the world. MOM hip resurfacings have raised concerns regarding poor clinical performance and increased in vivo wear was associated with steeply inclined acetabular components and translationally malpositioned components. The aim of this study was to compare the wear rates of MOM and COM total hip prostheses under adverse edge-loading conditions in a hip simulator test. COM and MOM 36 mm hip prostheses were tested in a hip simulator, with liners mounted to provide a clinical inclination angle of 55°. A simplified gait cycle and microseparation conditions were applied for two million cycles in 25% new born calf serum. The overall mean volumetric wear rate of COM bearings under adverse conditions was 0.36 ± 0.55 mm³/million cycles; this was significantly less than MOM wear (1.32 ± 0.91 mm³/million cycles). Under these adverse conditions; the contact zone on the head intersects the rim of the cup causing substantially elevated contact stresses, disrupting the protective boundary and mixed lubrication regime causing changes in types and severity of wear mechanisms. In COM bearings, the harder head does not become damaged when there is lubricant starvation and wear does not accelerate. In conclusion, COM bearings showed reduced wear compared to MOM bearings under standard and adverse clinically relevant simulator conditions and COM bearings may provide an advantage over MOM bearings under edge-loading conditions clinically.

Long-term results of cemented total hip arthroplasty in patients younger than 30 years and the outcome of subsequent revisions.

BackgroundThe number of total hip arthroplasties in patients under 30 years is increasing over the years. Almost all of them will face at least one or more future revisions in their life. Therefore, the implant used should have a high survival rate, and needs to be easily revisable resulting in a low re-revision rate. Several studies have evaluated the outcome of total hip arthroplasties in patients under 30 years. However, only a few reported on the follow-up outcome of 10 years or more. In addition, none of these reports published data of the subsequent revisions of these implants within their original report.MethodsWe studied historically prospective collected data of 48 consecutive patients (69 hips) younger than 30 years, treated with a cemented primary total hip prosthesis between 1988 and 2004. Since the last evaluation of this cohort, two patients were lost to follow-up. For all hip revisions in this cohort, again cemented implants were used, mostly in combination with bone impaction grafting. Kaplan-Meier survival curves at 10- and 15 years for the primary total hip arthroplasties and revisions were determined.ResultsThe mean age at time of primary surgery was 25 years (range, 16 to 29 years). Mean follow-up of the primary hips was 11.5 years (range, 7 to 23 years). During follow-up 13 revisions were performed; in 3 cases a two-stage total revision was performed for septic loosening and 9 cups were revised for aseptic loosening. There were no aseptic stem revisions. The 10 and 15-year survival rates with endpoint revision for aseptic loosening of the primary total hip were 90% (95% CI: 79 to 96) and 82% (95% CI: 65 to 92) respectively. None of our 13 subsequent revisions needed a re-revision within 10 years after re-implantation.ConclusionsCemented total hip implants in patients under 30 years have an encouraging outcome at 10 and 15 years after surgery in these young patients. The 13 revised hips, treated with bone grafting and the third generation cement technique, were performing well with no re-revisions within ten years after surgery.

Severe Metal-induced Osteolysis Many Years After Unipolar Hip Endoprosthesis

Modularity of the femoral head-neck junction provides increased intraoperative flexibility to the surgeon. Complications of this modularity include damage to the trunnion, with subsequent bone and/or soft tissue loss from adverse reactions to metal debris. We describe two cases of severe metal-induced osteolysis and soft tissue damage requiring revision 10 and 13 years following implantation of a unipolar endoprosthesis. Damage to the trunnion resulted in severe acetabular and trochanteric osteolysis and soft tissue loss requiring complex revision surgery. Several reports have shown the trunnion, the head-neck interface, and the neck-stem couple as the causes of this early failure secondary to metal ion release from mechanical fretting corrosion or from crevice corrosion at these modular interfaces. These reports have been in association with a total hip prosthesis rather than a unipolar endoprosthesis. Revision of a unipolar endoprosthesis is most commonly attributable to stem loosening or acetabular erosion from the large femoral head articulating on the host acetabular cartilage and not owing to failure of the trunnion. Trunnion damage resulting in a severe reaction to metal debris with acetabular osteolysis, erosion of the greater trochanter, and loss of the abductor mechanism can occur years after implantation of a cementless unipolar endoprosthesis. This raises questions regarding long-term safety of the modular interface of a contemporary cementless stem and a large-diameter unipolar head. We recommend long-term followup of patients with a unipolar endoprosthesis as early recognition and treatment are required to avoid a potentially complex revision.

Friction and Wear Behavior of Ti-6Al-7Nb Biomaterial Alloy

Titanium has been increasingly applied to biomedical application because of its improved mechanical characteristics, corrosion resistance and biocompatibility. However their application remains limited, due to the low strength and poor wear resistance of unalloyed titanium. The purpose of this study is to evaluate the friction and wear behavior of high-strength titanium alloys: Ti-6Al-7Nb used in femoral stem (total hip prosthesis). The oscillating friction and wear tests have been carried out in ambient air with oscillating tribotester in accord with standards ISO 7148, ASTM G99-95a, ASTM G 133-95 under different conditions of normal applied load (3, 6 and 10 N) and sliding speed (1, 15 and 25 mm.s-1), and as a counter pair we used the ball of 100C 6, 10 mm of diameter. The surface morphology of the titanium alloys has been characterized by SEM, EDAX, micro hardness, roughness analysis measurements. The behavior observed for both samples suggests that the wear and friction mechanism during the test is the same for Ti alloys, and to increase resistance to wear and friction of biomedical titanium alloys used in total hip prosthesis (femoral stems) the surface coating and treatment are required.

Treatment of Bilateral Recurrent Dislocation of Hip Pros-thesis with Malpositioned Well-Fixed Shell: A Case Report

Dislocations of total hip prostheses cause pain and patient dissatisfaction. Recurrent dislocations are difficult to treat mainly when the acetabular metal shell is well-fixed. The purpose of this article was to describe the surgical technique used for the treatment of a bilateral recurrent posterior dislocation after a cementless total hip prosthesis, caused by excessive inclination of acetabular components, in a 72-year-old patient. On both sides, acetabular metal shell, porouscoated, was well-fixed. Revision of the entire acetabular component could be an appropriate therapeutic option because it was malpositioned. Nevertheless, a conservative operation was performed. The metal shell was left in situ and the preexisting polyethylene liner was removed and replaced by a new undersized cross-linked polyethylene liner, then, cemented into the shell and properly oriented. An acetabular cemented augmentation reinforced by 3 cortical screws was associated with the reconstruction. This report suggests that cementation of new liner into a malpositioned well- fixed metal shell associated with an acetabular cemented augmentation is a simple and safe technique for the management of recurrent hip dislocation, for elderly patients in which it is advisable to avoid a major revision hip surgery by medical comorbidities. Nonetheless, further studies with medium-and long-term follow-up are needed to validate this technique.

Bioball universal modular neck adapter as a salvage for failed revision total hip arthroplasty

Management of recurrent dislocation of total hip arthroplasty is often a challenging and daunting task. Re-revision of such a total hip prosthesis may not be easy as the removal of a well-fixed, fully coated stem is extremely difficult. We managed to salvage instability in three revision hip cases in which the fully coated stem had subsided by using a bioball universal neck adapter without changing the femoral stem or acetabular cup.

Effect of the Cavity-Cavity Interaction on the Stress Amplitude in Orthopedic Cement

The presence of porosities in bone cement (polymethylmethacrylate) in total hip prosthesis (THP) cemented is necessary for the diffusion of antibiotics, but it is a critical characteristic of weakening by the effect of stress concentration and the interconnecting pores. The aim of this study was to analyse by the finite element method (FEM), the size influence of micro-cavities in cement assuming the junction cup-bone, and the effect of cavity-cavity interaction on the stress level and distribution in cement according to the human stance defined by the implant position axis compared to that of the cup.