Prosthetic Survival Research Articles

Overdentures in the Edentulous Mandible Supported by Implants and Retained by a Dolder Bar: A 5‐Year Prospective Study

This prospective study was performed to evaluate the outcomes of XiVE® S plus implants (Dentsply Friadent, Mannheim, Germany) following conventional restoration with bar structures and overdentures in the edentulous mandible. A total of 39 patients were treated with four interforaminal implants (n = 156) splinted by a Dolder bar. Overdentures were attached to the bars after 3 months of healing. As primary outcome measures, clinical and radiological parameters were evaluated at the time of implant placement (baseline) and once a year (1, 2, 3, 4, 5 years) after functional loading. Secondary outcome measures included (i) primary stability and surgical complications, as well as (ii) Periotest® (Medizintechnik Gulden, Modautal, Germany) values, implant survival, and prosthetic complications at baseline and follow-up. A total of 156 implants were placed. The vast majority (n = 149) were tightened to >30 Ncm, while torques in the range of 20-30 Ncm were obtained in the remaining cases (n = 7). Mean crestal bone levels around the implants were 0.41 mm at baseline and 1.04/1.20/1.34/1.45/1.44 mm after 1/2/3/4/5 years respectively. The mean values of the plaque, calculus, bleeding, and mucosal indices remained low throughout this period. The reported follow-up periods involved one implant loss after 3 months (survival rate: 99.4%) and one implant failure after 4 years (success rate: 98.4%). Prosthetic complications included factures of bars (n = 3) and denture teeth (n = 7). Prosthetic survival was 100%. Dolder bars to restore oral implants in the edentulous mandible appear to offer a high rate of implant survival, good stability of the peri-implant tissue, and a low rate of prosthetic complications.

Immediate functional loading of provisional implants in the reconstructed atrophic maxilla: preliminary results of a prospective study after 6 months of loading with a provisional bridge

Implant-prosthetic rehabilitation of atrophic maxillae remains a challenging problem. The aim of this paper is to describe a novel treatment for functional rehabilitation of the atrophic maxilla and to discuss preliminary results of this treatment protocol. A prospective pilot study was carried out in 10 patients who underwent bony reconstruction of atrophic maxillae under general anaesthesia, with autologous calvarial bone grafts and simultaneous placement of six provisional implants. The provisional implants were loaded with a provisional acrylic bridge 1 day after surgery. After 6 months, the provisional implants were removed and final implants were placed under local anaesthesia, again in an immediate loading concept with a provisional bridge, followed by a final bridge after another 6 months of healing. The bone grafts integrated well in all 10 patients without infectious complications. The prosthetic survival of the provisional bridge at the time of placing the implants was 100%. All final implants could be placed and immediately loaded with a second provisional bridge. Patient satisfaction was high due to limited postoperative inconvenience and immediate fixed prosthetic rehabilitation. The preliminary results of this pilot study demonstrate that this treatment protocol is a well tolerated treatment for patients with maxillary atrophy desiring dental rehabilitation.

Short-term effects of total hip arthroplasty using metal-on-metal prosthesis with large diameter femoral head

Objective To evaluate mid-term clinical outcomes associated with total hip arthroplasty using metal-on-metal prosthesis with large diameter femoral head. Methods From March 2007 to December 2009, 153 patients (177 hips) with advanced hip diseases undergoing large diameter femoral head metal-on-metal total hip arthroplasty in our hospital were retrospectively analyzed in this study. Clinical physical examination and radiographic examination were used to evaluate hip function and the incidence of complications (implant loosening and inflammatory pseudotumor); ICP-MS method was used to determine serum cobalt ion and chromium ion levels and compare with normal values; revision was set as the prosthesis endpoint to evaluate the five year survival rate of implant. Results A total of 145 patients (169 hips) were followed up for average 72.4 months (67-80 months), the follow-up rate was 94.8% (145/153). For the involved patients, 85 were male (104 hips), 60 were female (65 hips); age 20-78 years old, average 49.3±12.6 years old. All patients received ASRTM-XL large femoral head metal-on-metal total hip arthroplasty operation. At the end of follow-up, the average Harris hip score improved from 44.2±12.6 points preoperatively to 91.5±5.7 points. A total of 8 patients received revision, 3 for acetabular implant spinout-out and 5 for hip inflammatory pseudotumor. The prosthetic survival rate 5 years after operation was 95.3% (161/169) for revision. Serum cobalt (2.89 μg/L) and chromium (3.31 μg/L) ion levels were significantly increased compared with normal value (<0.5 μg/L). Conclusion For the fixation and friction interface disadvantages, acetabular implant spinout-out and inflammatory pseudotumor might occur for patient receiving large femoral head metal-on-metal THA. The mid-term prosthetic survival rate was also low, with metal ion levels increased significantly. For primary THA, large femoral head metal-on-metal prosthesis cannot be the first choice. Key words: Arthroplasty, replacement, hip; Prostheses and implants; Granuloma, plasma cell; Chromium alloys

Clinical outcomes of the KYOCERA Physio Hinge Total Knee System Type III after the resection of a bone and soft tissue tumor of the distal part of the femur

The KYOCERA Physio Hinge Total Knee System Type III (PHKIII) was developed to reconstruct bony defects of the distal femur. The PHKIII is originative in that the metallic parts are fully made of titanium alloy, and this prosthesis has a unique semi-rotating hinge joint and was designed especially for people with the Asian physical body-type. The clinical outcomes of the PHKIII after the resection of musculoskeletal tumors of the distal femur were evaluated. There were 41 males and 28 females with a median age of 48-years. The median duration of follow-up was 57 months. Eleven early complications and 37 late complications were observed, including 10 recurrences, 7 deep infections, 7 aseptic loosenings, 4 stem breakages, 4 displacements of shaft cap, and one wear of rotation sleeve. Twenty four prosthesis (35%) required a secondary operation because of complications. The five-year overall prosthetic survival rates, -prosthetic survival rate without aseptic loosening, and -limbs preservation rate were 85%, 90%, and 86%, respectively. The mean functional score according to the classification system of the Musculoskeletal Tumor Society was 20.5 points (68%). Although continuous follow-up is required, reconstructions using PHKIII are considered to achieve more acceptable functional results.

Implant-supported fixed prostheses in the edentulous maxilla: 8-year prospective results

The purpose of this prospective study was to evaluate the long-term survival and success rates of implants and screw-retained, full-arch prostheses placed in edentulous maxillae over 8 years of function. A total of 106 Astra Tech implants were placed in the maxillae of 17 edentulous patients in a one-stage surgical approach. After a healing period of 6 months, the patients received fixed screw-retained bridges. Follow-up visits, including clinical and radiographic examinations, were performed after 6 months and at yearly intervals. Implant survival, implant success, and marginal bone-level changes were defined as the primary outcome variables. The secondary aims were to report periodontal pathogens at 5 years' follow-up and patients' satisfaction at the 8-year follow-up. The overall observation time was 8 years. One patient died during the study and one implant failed during the healing period, yielding an 8-year cumulative implant survival rate of 99%. The prosthetic survival rate was 100%. The mean crestal bone loss amounted to 0.3 ± 0.72 mm. Patients' subjective evaluations demonstrated an overall high level of satisfaction. In all cases, except for one, microbiologic probing of the peri-implant sulcus after 5 years showed no higher incidence of periodontal pathogens. Screw-retained, full-arch restorations on six implants in an edentulous maxilla are a predictable and highly successful treatment concept as observed throughout this study with an observation period of 8 years of function, in particular with respect to low crestal bone loss and high patient satisfaction.

Guided Surgery and Presurgical Prosthesis: Preliminary Results of 33 Fully Edentulous Maxillae Treated in Accordance with the NobelGuide® Protocol

The aim of this study was to present the preliminary results of 33 edentulous maxillary patients treated using the Nobelguide (Nobel Biocare AB, Göteborg, Sweden) technique. Thirty-three patients were treated according to the conventional protocol of the Nobelguide technique in two clinical centers. This group of patients received 211 implants. Monitoring was carried out for over 12-51 months, depending on the patient. The Nobelguide protocol was used for all patients. Of the 211 implants loaded, four were lost (1.9%). The implant survival rate was therefore 98.1%. The prosthetic survival rate was 100%. There were some per-operative complications (four) and some postoperative complications (10 fractures of resin). These preliminary results seemed rather promising. These were the first cases of experienced surgeons who needed to learn a new implant placement protocol. It was clear that analysis and understanding of the system were essential in order to obtain such a success. Only one implant was replaced without there being any impact on the prosthesis survival rate which is 100%.

Computer-Assisted Navigation Software Advancements Improve the Accuracy of Total Knee Arthroplasty

The purpose of this study was to evaluate the effectiveness of software advancements in improving total knee component positioning and limb alignment when using computer-aided navigation. A single total joint fellowship-trained surgeon performed unilateral total knee arthroplasty on 315 patients using conventional techniques or with assistance from computer navigation software. Preoperative and postoperative x-ray measurements were taken and analyzed. Our previous work demonstrated a statistically significant improvement ( P < .02) in limb alignment (±3° of biomechanical neutral) when using version 2.0 software (93%) when compared with conventional techniques (82%). Further improvement was demonstrated with the version 3.1 software (99%, P < .03). The tourniquet times were recorded for each group and showed a significant improvement with the 3.1 software (conventional = 74 minutes, 2.0 navigation = 90 minutes, and 3.1 navigation = 73 minutes). The Stryker 2.0 software (Stryker Orthopedics, Mahwah, NJ) tourniquet time was statistically significantly longer than either the conventional or the 3.1 group ( P < .001). Outcomes-based studies will be required to see if these factors will lead to improved patient function and/or prolonged prosthetic survival rates.

Linked Elbow Replacement: A Salvage Procedure for Distal Humeral Nonunion

Nonunion is a challenging and not uncommon complication of distal humeral fractures. Our long-term experience with linked semiconstrained total elbow arthroplasty as a salvage procedure for patients with distal humeral nonunion not amenable to internal fixation was investigated. Ninety-one consecutive patients (ninety-two elbows) underwent total elbow arthroplasty for the treatment of a distal humeral nonunion, and the results were reviewed at a mean of 6.5 years postoperatively. Patients' charts and anteroposterior and lateral radiographs made prior to and immediately after the joint replacement and at the time of the latest follow-up were reviewed to identify intraoperative and postoperative complications, and radiographic evidence of loosening or bushing wear. The outcome measures consisted of prosthetic survival, with implant removal as the end point for failure, and the Mayo Elbow Performance Score (MEPS). At the time of the most recent follow-up, joint stability had been initially restored in all patients, including nine who had had a grossly flailed elbow. Sixty-seven (74%) of the patients had no pain or mild pain at the time of the latest follow-up, whereas seventy-nine patients (87%) had had moderate or severe pain prior to the surgery. While 85% (seventy-seven) of the ninety-one patients rated the outcome as better or much better, twenty patients (22%) had a fair or poor MEPS. A total of forty-four complications occurred in forty elbows, and there were thirty-two reoperations, twenty-three of which involved implant revision or removal. Factors that increased the risk of implant failure were a patient age of less than sixty-five years, two or more prior surgical procedures, and a history of infection. The rate of prosthetic survival without removal or revision for any reason was 96% at two years, 82% at five years, and 65% at both ten and fifteen years. Linked semiconstrained total elbow arthroplasty is a salvage procedure that can provide pain relief and restore motion and function in patients with a distal humeral nonunion that is not amenable to internal fixation. Substantial risk factors for failure include an age of less than sixty-five years, multiple previous surgical procedures, and any history of infection.

No Superiority of Cemented Metal-on-Metal vs Metal-on-Polyethylene THA at 5-Year Follow-up

A randomized controlled trial was performed to compare the cemented Stanmore metal-on-metal (Biomet, Warsaw, Indiana) total hip arthroplasty (THA; 102 hips) to the cemented Stanmore metal-on-polyethylene (Biomet) THA (98 hips). The primary outcome was clinical performance. Radiological performance, serum cobalt analysis, and prosthetic survival were secondary outcome measures. At a mean follow-up of 5.6 years, 5 patients were lost to follow-up, 18 died, and 4 were revised (3 metal-on- metal, 1 metal-on-polyethylene). Harris Hip Scores improved from 48 to 90 in the metal-on-metal patients (P<.001) and from 46 to 87 in the metal-on-polyethylene patients (P<.001). Oxford Hip Scores changed from 40 to 19 in the metal-on-metal group (P<.001) and from 40 to 18 in the metal-on-polyethylene group (P<.001). For both Harris and Oxford Hip Scores, there was no significant difference between the 2 groups. Five-year survival with revision for any reason was 97% (95% CI 93%-100%) in the metal-on-metal group and 99% (95% CI 97%-100%) in the metal-on-polyethylene group. All revisions were indicated for aseptic loosening (metal-on-metal: 3 cup revisions; metal-on-polyethylene: 1 total revision). At 5-year follow-up, cemented metal-on-metal THA showed no clinical superiority over metal-on-polyethylene THA.

Early Equivalence of Uncemented Press-fit and Compress® Femoral Fixation

Bone ingrowth promises more durable biologic fixation of megaprostheses. The relative performance of different types of fixation is unknown. We compared the fixation of two forms of biologically fixed femoral components: an intramedullary uncemented press-fit stem (UCS; Group 1, 50 patients) and a Compress((R)) uncemented fixation (CPS; Group 2, 41 patients). In Group 1, the overall Kaplan-Meier prosthetic survival rates were 85% at 5 and 71% at 10 years. Most failures were long-term developments. Aseptic loosening was the primary cause of failure. Stem diameters less than 13.5 mm and a diaphyseal/stem coefficient greater than 2.5 mm were associated with decreased prosthetic survival. In Group 2, the overall rate of CPS survival was 88% at 5 years. Failure of femoral fixation or fracture during the first year was the main reason for revision. Five-year survival rates were similar between the groups and we observed no difference in the functional success of the implants. We found no failures after 1-year followup in Group 2 (CPS). Any difference in prosthetic survival can only be proven by longer-term study or a randomized trial. Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Total Elbow Arthroplasty in Patients Forty Years of Age or Less

It is generally accepted that prosthetic elbow replacement should be avoided in young patients because of an anticipated high rate of early failure. The purpose of this paper was to define the success, prosthetic survival rate, and problems encountered in patients who were treated with a semiconstrained total elbow arthroplasty when they were forty years of age or less. We retrospectively reviewed the records of 758 patients who had undergone primary arthroplasty with the Coonrad-Morrey total elbow prosthesis for any reason between 1982 and 2003. We identified fifty-five total elbow arthroplasties that had been performed in forty-nine patients (thirty-eight women and eleven men) who were forty years of age or less (mean, thirty-three years) at the time of the operation and that had been followed for a minimum of five years. Six patients had a bilateral procedure. The indication for the arthroplasty was inflammatory arthritis in thirty patients and posttraumatic arthritis in nineteen. Patients with hemophilia or a neoplasm were excluded. The medical record data were used to calculate the preoperative and postoperative Mayo Elbow Performance Score. The mean duration of follow-up was ninety-one months. During this period, twelve (22%) of the elbows had undergone a subsequent surgical procedure: four because of loosening, three because of triceps weakness, three because of wear, and two because of deep infection. On the basis of the Mayo Elbow Performance Score at the last review, thirty-six results (65%) were considered to be excellent; fifteen (27%), good; three (5%), fair; and one (2%), poor. Semiconstrained total elbow arthroplasty in young patients was associated with a 22% revision rate at a mean of ninety-one months, and the rate of revision was significantly higher for patients with posttraumatic arthritis. Despite this revision rate, fifty-one elbows (93%) had a good or excellent Mayo Elbow Performance Score.

Acetabular Revision with Impacted Morselized Cancellous Bone Graft and a Cemented Cup in Patients with Rheumatoid Arthritis

We previously reported our results at a minimum of three years after thirty-five revisions of total hip arthroplasty acetabular components in twenty-eight patients with rheumatoid arthritis. The revisions were performed with use of impacted morselized bone graft and a cemented cup. This update report presents the results at eight to nineteen years after the surgery, which, to our knowledge, is the longest follow-up available in the literature. No patient was lost to follow-up. Since our previous report, there were two additional cup failures due to aseptic loosening, at ten and sixteen years postoperatively. Kaplan-Meier analysis showed the probability of survival of the acetabular component at twelve years to be 80% (95% confidence interval, 65% to 95%) with removal of the cup for any reason as the end point and 85% (95% confidence interval, 71% to 99%) with aseptic loosening as the end point. Cup revisions performed with cement and use of impaction bone-grafting in patients with rheumatoid arthritis led to acceptable long-term prosthetic survival rates. This technique is attractive from a biological standpoint because of the possibility of maintaining acetabular bone stock.

The Knee Arthroplasty Trial (KAT)

The aim of continued development of total knee replacement systems has been the further improvement of the quality of life and increasing the duration of prosthetic survival. Our goal was to evaluate the effects of several design features, including metal backing of the tibial component, patellar resurfacing, and a mobile bearing between the tibial and femoral components, on the function and survival of the implant. A pragmatic, multicenter, randomized, controlled trial involving 116 surgeons in thirty-four centers in the United Kingdom was performed; 2352 participants were randomly allocated to be treated with or without a metal backing of the tibial component (409), with or without patellar resurfacing (1715), and/or with or without a mobile bearing (539). Randomization to more than one comparison was allowed. The primary outcome measures were the Oxford Knee Score (OKS), Short Form-12, EuroQol-5D, and the need for additional surgery. The results up to two years postoperatively are reported. Functional status and quality-of-life scores were low at baseline but improved markedly across all trial groups following knee replacement (mean overall OKS, 17.98 points at baseline and 34.82 points at two years). Most of the change was observed at three months after the surgery. Six percent of the patients had additional knee surgery within two years. There was no evidence of differences in clinical, functional, or quality-of-life measures between the randomized groups at two years. Patients have substantial improvement following total knee replacement. This is the first adequately powered randomized controlled trial, of which we are aware, in which the effects of metal backing, patellar resurfacing, and a mobile bearing were investigated. We found no evidence of an effect of these variants on the rate of early complications or on functional recovery up to two years after total knee replacement.

A new approach to rehabilitate the severely atrophic maxilla using extramaxillary anchored implants in immediate function: A pilot study

There is a need to simplify implant treatment for complete arch rehabilitation of severely atrophic maxillae, as well as a desire to eliminate grafting and provide quality rehabilitation in terms of esthetics, function, and comfort for the patient. The purpose of this study was to report on the initial results of rehabilitation of complete edentulous atrophied maxillae using a new surgical approach and a newly designed extra long implant, placed externally to the maxillary bone (implant only accommodated in the maxillary bone) and anchored in the zygomatic bone. The pilot study included 29 patients (21 women and 8 men), with an age range of 32-75 years (mean=52.4 years), followed between 6 and 18 months, with a mean follow-up time of 1 year. The patients presenting severe atrophy in the maxillae (Cawood and Howell classification C-VI and D-V or D-VI) were rehabilitated either by using 1, 2, or 4 extra long implants (30 to 50 mm in length; Nobel Biocare AB) placed in the zygomatic bone in conjunction with standard implants (24 patients): or 4 extra long implants (5 patients), all placed in immediate function. The criteria used to evaluate implant outcome were: implants function as support for reconstruction; implants stable when individually and manually tested; no signs of infection observed; and good esthetic outcome of the rehabilitation. To evaluate the secondary objective of assessing the stability and health of the soft tissue covering the implants, the mucosal seal efficacy evaluation index (MSEE) was used. This index was modified from the probing depth for standard implants and performed with a 0.25-N calibrated plastic periodontal probe measuring the depth (mm) of the space between the implant and the mucosa. Data were analyzed with descriptive and inferential analyses. The cumulative implant survival rate and prosthetic survival rate at 1 year were 98.5% and 100%, respectively. The mean and median values of the MSEE at 2 months (2.9 mm, 3 mm), 4 months (2.5 mm, 2.8 mm), 6 months (2.9 mm, 2.8 mm), and 1 year (2.8 mm, 2.5 mm) are comparable to the values of probing depths assessed for standard implants. The results indicate that, within the limitations of this preliminary study, the rehabilitation of maxillae with severe atrophy can be performed using extra long implants placed external to the maxilla and anchored only in the zygomatic bone, and placed in immediate function.

Large head metal-on-metal cementless total hip arthroplasty versus 28mm metal-on-polyethylene cementless total hip arthroplasty: design of a randomized controlled trial

BackgroundOsteoarthritis of the hip is successfully treated by total hip arthroplasty with metal-on-polyethylene articulation. Polyethylene wear debris can however lead to osteolysis, aseptic loosening and failure of the implant. Large head metal-on-metal total hip arthroplasty may overcome polyethylene wear induced prosthetic failure, but can increase systemic cobalt and chromium ion concentrations. The objective of this study is to compare two cementless total hip arthroplasties: a conventional 28 mm metal-on-polyethylene articulation and a large head metal-on-metal articulation. We hypothesize that the latter arthroplasties show less bone density loss and higher serum metal ion concentrations. We expect equal functional scores, greater range of motion, fewer dislocations, fewer periprosthetic radiolucencies and increased prosthetic survival with the metal-on-metal articulation.MethodsA randomized controlled trial will be conducted. Patients to be included suffer from non-inflammatory degenerative joint disease of the hip, are aged between 18 and 80 and are admitted for primary cementless unilateral total hip arthroplasty. Patients in the metal-on-metal group will receive a cementless titanium alloy acetabular component with a cobalt-chromium liner and a cobalt-chromium femoral head varying from 38 to 60 mm. Patients in the metal-on-polyethylene group will receive a cementless titanium alloy acetabular component with a polyethylene liner and a 28 mm cobalt-chromium femoral head. We will assess acetabular bone mineral density by dual energy x-ray absorptiometry (DEXA), serum ion concentrations of cobalt, chromium and titanium, self reported functional status (Oxford hip score), physician reported functional status and range of motion (Harris hip score), number of dislocations and prosthetic survival. Measurements will take place preoperatively, perioperatively, and postoperatively (6 weeks, 1 year, 5 years and 10 years).DiscussionSuperior results of large head metal-on-metal total hip arthroplasty over conventional hip arthroplasty have been put forward by experts, case series and the industry, but to our knowledge there is no randomized controlled evidence.ConclusionThis randomized controlled study has been designed to test whether large head metal-on-metal cementless total hip arthroplasty leads to less periprosthetic bone density loss and higher serum metal ion concentrations compared to 28 mm metal-on-polyethylene cementless total hip arthroplasty.Trial registrationNetherlands Trial Registry NTR1399

Linked Elbow Replacement: A Salvage Procedure for Distal Humeral Nonunion

Nonunion is a challenging and not uncommon complication of distal humeral fractures. Our long-term experience with linked semiconstrained total elbow arthroplasty as a salvage procedure for patients with distal humeral nonunion not amenable to internal fixation was investigated. Ninety-one consecutive patients (ninety-two elbows) underwent total elbow arthroplasty for the treatment of a distal humeral nonunion, and the results were reviewed at a mean of 6.5 years postoperatively. Patients' charts and anteroposterior and lateral radiographs made prior to and immediately after the joint replacement and at the time of the latest follow-up were reviewed to identify intraoperative and postoperative complications, and radiographic evidence of loosening or bushing wear. The outcome measures consisted of prosthetic survival, with implant removal as the end point for failure, and the Mayo Elbow Performance Score (MEPS). At the time of the most recent follow-up, joint stability had been initially restored in all patients, including nine who had had a grossly flailed elbow. Sixty-seven (74%) of the patients had no pain or mild pain at the time of the latest follow-up, whereas seventy-nine patients (87%) had had moderate or severe pain prior to the surgery. While 85% (seventy-seven) of the ninety-one patients rated the outcome as better or much better, twenty patients (22%) had a fair or poor MEPS. A total of forty-four complications occurred in forty elbows, and there were thirty-two reoperations, twenty-three of which involved implant revision or removal. Factors that increased the risk of implant failure were a patient age of less than sixty-five years, two or more prior surgical procedures, and a history of infection. The rate of prosthetic survival without removal or revision for any reason was 96% at two years, 82% at five years, and 65% at both ten and fifteen years. Linked semiconstrained total elbow arthroplasty is a salvage procedure that can provide pain relief and restore motion and function in patients with a distal humeral nonunion that is not amenable to internal fixation. Substantial risk factors for failure include an age of less than sixty-five years, multiple previous surgical procedures, and any history of infection.

Improved Survivorship of Hybrid Metal-on-Metal Hip Resurfacing with Second-Generation Techniques for Crowe-I and II Developmental Dysplasia of the Hip

The purpose of this study was to determine the influence of improved femoral fixation techniques on the survivorship of metal-on-metal total hip resurfacing prostheses in patients with developmental dysplasia of the hip and to report the long-term results of our patients managed earlier with first-generation fixation techniques. One hundred and three hips (ninety patients) were resurfaced for osteoarthritis secondary to developmental dysplasia. The mean age of the patients was forty-seven years, and 77% were women. Most hips (94%) were Crowe class I, but 43% had femoral head defects of >1 cm in size. The clinical results of these hips were compared with those of a group of patients with other etiologies, largely dominated by idiopathic osteoarthritis (78%). All clinical scores improved significantly (p < 0.0001) and were comparable with those of patients with other etiologies except for the postoperative activity scores, which were lower (7.0 compared with 7.5). Range of motion was greater for the patients with dysplasia than for the patients with other etiologies. Seven hips that were resurfaced with the first-generation femoral fixation techniques and one hip that was resurfaced with the second and third-generation techniques had conversion to total hip arthroplasty. This difference was found to be significant (p = 0.032) in a multivariate, time-dependent analysis after adjustment for other covariates known to affect prosthetic survival. There was no loosening of the acetabular component in this series. The current improvements in the short-term to midterm results after resurfacing in patients with developmental dysplasia of the hip in whom more current techniques were used are encouraging and allow for greater expectations regarding the elimination of short-term failures and improved long-term durability of resurfacing in this population.

Eleven Years of Experience With Metal-on-Metal Hybrid Hip Resurfacing: A Review of 1000 Conserve Plus

Hip resurfacing is currently the fastest growing hip procedure worldwide. We reviewed 1000 hips in 838 patients who received a Conserve Plus (Wright Medical Technology, Inc., Arlington, Tenn) resurfacing at a single institution. The mean age of the patients was 50.0 years with 74.7% male. The hips were resurfaced irrespective of femoral defect size or etiology. The mean follow-up was 5.6 years (range, 1.1-11.0 years). All clinical scores improved significantly ( P < .05). There was no acetabular component loosening. Ten were converted to total hip arthroplasty for femoral neck fracture, 20 for femoral loosening, 2 for sepsis, and 1 for recurrent subluxations. The 5-year survivorship was 95.2% with no failures in hips implanted since 2002. Short-term failures can be prevented. First-generation surgical technique and a low body mass index were the most important risk factors for the procedure. Improvements in bone preparation significantly increased prosthetic survival in hips with risk factors for failure.

10 Years of Experience with Metal-On-Metal Hybrid Hip Resurfacing: A Review of 1000 Conserve Plus

Hip resurfacing is currently the fastest growing hip procedure worldwide. We reviewed 1000 hips in 838 patients who received a Conserve Plus (Wright Medical Technology, Inc., Arlington, Tenn) resurfacing at a single institution. The mean age of the patients was 50.0 years with 74.7% male. The hips were resurfaced irrespective of femoral defect size or etiology. The mean follow-up was 5.6 years (range, 1.1-11.0 years). All clinical scores improved significantly (P < .05). There was no acetabular component loosening. Ten were converted to total hip arthroplasty for femoral neck fracture, 20 for femoral loosening, 2 for sepsis, and 1 for recurrent subluxations. The 5-year survivorship was 95.2% with no failures in hips implanted since 2002. Short-term failures can be prevented. First-generation surgical technique and a low body mass index were the most important risk factors for the procedure. Improvements in bone preparation significantly increased prosthetic survival in hips with risk factors for failure.

The management of an endodontically abscessed tooth: patient health state utility, decision-tree and economic analysis

BackgroundA frequent encounter in clinical practice is the middle-aged adult patient complaining of a toothache caused by the spread of a carious infection into the tooth's endodontic complex. Decisions about the range of treatment options (conventional crown with a post and core technique (CC), a single tooth implant (STI), a conventional dental bridge (CDB), and a partial removable denture (RPD)) have to balance the prognosis, utility and cost. Little is know about the utility patients attach to the different treatment options for an endontically abscessed mandibular molar and maxillary incisor. We measured patients' dental-health-state utilities and ranking preferences of the treatment options for these dental problems.MethodsForty school teachers ranked their preferences for conventional crown with a post and core technique, a single tooth implant, a conventional dental bridge, and a partial removable denture using a standard gamble and willingness to pay. Data previously reported on treatment prognosis and direct "out-of-pocket" costs were used in a decision-tree and economic analysisResultsThe Standard Gamble utilities for the restoration of a mandibular 1st molar with either the conventional crown (CC), single-tooth-implant (STI), conventional dental bridge (CDB) or removable-partial-denture (RPD) were 74.47 [± 6.91], 78.60 [± 5.19], 76.22 [± 5.78], 64.80 [± 8.1] respectively (p < 0.05). Their respective Willingness-to-Pay ($CDN) were 1,782.05 [± 361.42], 1,871.79 [± 349.44], 1,605.13 [± 348.10], 1,351.28 [± 368.62] (p < 0.05).The standard gamble utilities for the restoration of a maxillary central incisor with a CC, STI, CDB and RPD were 88.50 [± 6.12], 90.68 [± 3.41], 89.78 [± 3.81] and 91.10 [± 3.57] respectively (p > 0.05). Their respective willingness-to-pay ($CDN) were: 1,782.05 [± 361.42], 1,871.79 [± 349.44], 1,605.13 [± 348.10] and 1,351.28 [± 368.62]. A statistical difference was found between the utility of treating a maxillary central incisor and mandibular 1st-molar (p < 0.05).The expected-utility-value for a 5-year prosthetic survival was highest for the CDB and the STI treatment of an abscessed mandibular molar (74.75 and 71.47 respectively) and maxillary incisor (86.24 and 84.91 respectively). This held up to a sensitivity analysis when the success of root canal therapy and the risk of damage to the adjacent tooth were varied. The RPD for both the molar and incisor was the favored treatment based on a cost-utility (3.85 and 2.74 CND$ per year of tooth saved respectively) and cost-benefit analysis (0.92 to 0.60 CND$ of cost per $ of benefit, respectively) for a prosthetic clinical survival of 5-years.ConclusionThe position of the abscessed tooth and the amount of insurance coverage influences the utility and rank assigned by patients to the different treatment options. STI and CDB have optimal EUVs for a 5-year survival outcome, and RPD has significantly lower cost providing the better cost:benefit ratio.