Showing papers on "Prosthesis published in 1999"

Survival of the Brånemark implant in partially edentulous jaws: a 10-year prospective multicenter study.

Abstract: A total of 127 partially edentulous patients, treated according to the Branemark protocol, was followed for 10 years after completion of prosthetic treatment. The patients ranged in age from 18 to 70 years, and 57% were female. Four hundred sixty-one implants were placed in 56 maxillae and 71 mandibles. In 125 patients, 163 fixed partial prostheses were attached to the implants; a majority of the prostheses (83%) were located in posterior regions. At the end of the 10-year period, 73% of the implants could be traced either as failed or in function, providing cumulative implant survival rates of 90.2% and 93.7% for the maxilla and mandible, respectively. Of the original fixed prostheses, 63% (cumulatively 86.5%) were still in use, whereas the level of continuous cumulative prosthesis function, including primary and remade restorations, was 94.3% at the end of the evaluation period. Marginal bone resorption at the implants was low (mean = 0.7 mm), and mucosal health was good. No severe complications apart from the above-mentioned implant and prosthetic failures were reported. The Branemark Implant System is a safe and predictable method for restoring partially edentulous patients, as demonstrated by this 10-year follow-up investigation.

Anti-Infective Efficacy of Silver-Coated Medical Prostheses

Abstract: Medical prostheses constitute an indispensable component of modern health care. Like other approaches of medical intervention, the insertion of medical prostheses can be associated with serious complications. The ongoing advances in the mechanical properties of medical prostheses have not necessarily resulted in lower rates of prosthesis-related infection. Infection remains the most common serious complication of medical prostheses. For instance, vascular catheters account for most cases of nosocomial bloodstream infection [1], and catheterrelated urinary tract infection is the most frequent nosocomial infection [2]. Two decades ago, infections associated with medical prostheses accounted for about half of all nosocomial infections [2]. Today, with their increasing use, medical prostheses are expected to cause a larger portion of cases of nosocomial infections, particularly in the subpopulations of immunocompromised, chronically ill, and elderly subjects. Infections associated with medical prostheses result in major morbidity and can be life-threatening. For instance, the mortality associated with prosthetic valve endocarditis ranges from 30% to 80% in patients with early-onset infection and from 20% to 40% in patients with late-onset endocarditis [3]. Often, infections associated with medical prostheses are very expensive to manage, and their cure requires removal of the infected prosthesis. For example, findings from the Dutch Trauma Trial indicated a mean cost of $22,000 (in 1991 dollars) to treat a patient who developed a deep wound infection after internal fixation of a closed fracture [4].

Metal-on-metal bearing in hip prosthesis generates 100-fold less wear debris than metal-on-polyethylene.

Abstract: Aseptic loosening due to osteolysis in total hip replacement has been related to wear debris released from prosthetic components. Retrospective longterm observations of patients with the metal-on-metal prosthesis has shown long-term survivorship and good mechanical performance. Thus, the new and modified metal-on-metal prosthesis has been introduced on the market. Historical clinical data from the 1st generation metal-on-metal hip prosthesis may not be relevant for the 2nd generation of metal-on-metal hip prosthesis. Therefore, preclinical testing of the prosthesis must be conducted before clinical evaluation. We assessed the tribological performance of the metal-on-metal prosthesis versus the metal-on-polyethylene prosthesis introduced on the market as Metasul and Protasul, respectively. In a 12-channel joint simulator, 6 metal-on-metal bearing and 3 metal on polyethylene prostheses were tested, with the same number of corresponding soak controls. The wear was assessed gravimetrically. The "steady-state" wear-rates from the metal-on-metal prosthesis were almost 100 times less than that from the metal-on-polyethylene prosthesis. The tribological wear performance of the metal-on-metal hip prosthetic system is promising.

Surgical-prosthodontic reconstruction of advanced maxillary bone compromise with autogenous onlay block bone grafts and osseointegrated endosseous implants: a 12-year study of 32 consecutive patients.

Abstract: During a 12-year period (1984 to 1997), 32 consecutive patients with advanced maxillary bone compromise received surgical-prosthodontic rehabilitation. The most frequent procedure used was maxillary augmentation with a free nonvascularized autogenous onlay block bone graft, and the average time of prosthesis function was 67 months. Twenty-eight patients underwent a 1-stage procedure, in which endosseous implants were placed simultaneously for internal rigid skeletal fixation of the onlay bone graft, and 4 patients underwent a 2-stage procedure, in which endosseous implants were placed secondarily 6 months after complete healing of the previously placed onlay bone graft, which initially was stabilized by titanium miniplates and lag screws. Treatment success was evaluated separately for the first 7 consecutively treated patients (developmental group) and for the next 25 consecutive patients (routine group). Assessment was made of implant survival relative to etiology of bone loss, implant type and length, type of prosthesis, type of opposing occlusion, type of surgical procedure, and presence of discontinuity. The implant survival rate was 91% in the 25 routine patients and 65% in the 7 developmental patients. Implant type and length, prosthesis type, opposing occlusion, and the presence or absence of discontinuity significantly impacted treatment outcome. Onlay block bone graft success (96%) in all 32 treated patients and prosthetic success (96%) in the last 25 patients was recorded. (INT J ORAL MAXILLOFAC IMPLANTS 1999;14:197‐209)

Total condylar knee arthroplasty. 16- to 21-year results.

Abstract: This study presents long term results of arthroplasty with posterior cruciate retention using the Total Condylar Knee implant. From 1976 to 1982, 139 patients had 159 knee arthroplasties using Total Condylar Knee prostheses. Sixty-three patients (72 knees) were available for followup at a minimum of 16 years (range, 16-21 years). The average age of the patients at the time of surgery was 61 years. There were 21 men and 42 women. Patients with 68 knees had osteoarthrosis, three had rheumatoid arthritis and one had posttraumatic arthritis. There were five delayed complications. One patient (one knee) underwent revision surgery and two patients (two knees) declined revision surgery because they were considered to be high surgical risks, as determined by their internists. The average preoperative score was 40.3 points and improved to 88.4 points at followup. Eighty-seven percent of the patients had a score equal to or more than 85 points at last evaluation. Prosthesis survivorship at 20 years was 98.6% for patients who had revision surgery. No femoral components were revised for aseptic loosening. Retention of the posterior cruciate in Total Condylar Knee prosthesis produces results comparable with the results of the original Total Condylar Knee prosthesis with cruciate sacrifice.

Long-term results of the GSB III elbow arthroplasty

Abstract: Between 1978 and 1986, 59 patients received a GSB III elbow prosthesis, six of them in both elbows. Rheumatoid arthritis (RA) was the underlying cause in 51 of the patients and post-traumatic osteoarthritis (PTOA) in eight. Of these, 24 patients (28 prostheses) have since died; two, both operated on bilaterally, had had their implants for more than ten years and had already been assessed for inclusion in the long-term follow-up. Two patients, each with one elbow prosthesis, have been lost to follow-up and three males who are still living (two with PTOA, one with juvenile RA) had their prosthesis removed before ten years had elapsed. The remaining 32 patients (28 RA, 4 PTOA) with 36 GSB III elbows were examined clinically and radiologically after a mean period of 13.5 years. Pain was considerably reduced in 91.6%. Mobility was increased by 37° in those with RA and by 67° in those with PTOA. There were three cases of aseptic loosening and three of deep infection. The main complication was disassembly of the prosthetic component in nine elbows (13.8%). This last group included two patients with postoperative fractures unrelated to the operative technique and one with neuropathic arthritis. Ulnar neuritis occurred in two patients. Since 87.7% of all the GSB III prostheses implanted in this period remained in situ, our results are comparable with those for hip and knee arthroplasty.

Geometric analysis of commonly used prosthetic systems for proximal humeral replacement

Abstract: Background: The anatomy of the proximal part of the humerus is extremely variable. The extent to which existing prosthetic systems and operative technique allow replication of this variability has not been established. Methods: Four commonly used press-fit prosthetic systems for shoulder arthroplasty were compared with respect to their ability to match the superior-inferior and medial-lateral dimensions of the articular surface in twenty-one cadaveric humeri. The comparisons were accomplished with a computer optimization algorithm that searched a database of prosthetic geometry and selected the best match to the original anatomy. The algorithm assumed an osteotomy of the humeral head at an angle equivalent to the stem-head angle of the prosthesis, without violation of the greater tuberosity or the metaphyseal bone. The best match was defined as the prosthetic combination (stem and head) that least displaced the center of rotation and the articular surface, with both factors weighted equally. Results: None of the prosthetic systems that were evaluated allowed identical replication of the articular surface. Rather, they displaced the center of rotation a mean of 14.7 millimeters (range, 3.3 to 31.4 millimeters) from its original position. To reach this minimized displacement, the prosthetic combinations that were selected by the algorithm also resulted in a mean diminution of the arc of the articular surface (a smaller head size) of 26 degrees (range, 11 to 41 degrees). In every instance, the selected prosthesis imposed a superior and lateral shift of the center of rotation that in effect shifted a smaller prosthetic humeral head up the slope of the humeral osteotomy. Conclusions: Press-fit prosthetic systems for shoulder arthroplasty that are commonly used necessitate marked alterations of the original anatomy. To the extent that a shoulder arthroplasty is an attempt to reproduce the normal anatomy, these findings have profound implications for operative technique and future prosthetic design. Clinical Relevance: We believe that the superior position of the prosthetic head predicted by the present study plays a role in late complications of shoulder arthroplasty, such as rotator cuff tendinopathy, superior humeral migration, and loosening of the glenoid component.

Reoperations for acute prosthetic thrombosis and pannus: an assessment of rates, relationship and risk.

Abstract: Objective: Mechanical valvular prostheses have the advantage of longevity but carry a risk of thrombosis which is dependant on valve design, materials and host-related interface. While pannus is common to both biologic and mechanical valves, acute prosthetic thrombosis is mostly a complication of mechanical valves; therefore we investigated to find rates and risk of these obstructive complications. Methods: Between 1/1/70 and 31/12/97, 2680 patients received at least one mechanical prosthesis in the aortic or mitral or tricuspid position and a total of 3014 operations were performed. Follow-up included 18523 years and was 98% complete. Incidence rates, Kaplan-Meier estimates, modeling of the hazard and multivariate analysis in the hazard domain were used in the analysis. Results: Overall survival was 76%, 64%, 51%, 38.5% and 29% at 5, 10, 15, 20 and 25 years, respectively. It was significantly better in aortic than in mitral than in double prosthesis. 290 patients received a single reoperation, 37 a second, six a third and one a fourth reoperation. Two-hundred and fifty-one of these reoperations were exclusively due to malfunction of mechanical prosthesis, nine to malfunction of both mechanic and biologic prostheses. Most frequent reoperative indications was dehiscence (133), pannus (48) and thrombosis (29). The linearized rate of reoperations for pannus was 0.24%/patient per year, for valvular thrombosis 0.15%/patient per year. The shape of the thrombotic hazard was constant (at random) and the relative risk 12 times higher for tricuspid prosthesis, seven times higher for mitral prosthesis. Multivariate analysis controlling for prosthetic position, age, sex and prosthetic size, showed a 67% risk reduction with larger prosthesis (>27 mm), a 69% risk reduction with the Sorin tilting disk prosthesis and an 83% risk reduction with the bileaflet prosthesis. Pannus hazard shows a delayed exponential rise and was two times higher in tricuspid and three times higher in mitral position. Multivariate analysis showed a 50% risk reduction with larger prosthesis, an II times higher hazard of old (caged-disk, caged ball) prosthesis and a three times higher hazard of Lillehei-Kaster prosthesis. Reoperation for thrombosis has a 62% perioperative (30 days) survival compared to 92% survival of pannus reoperation. Conclusions: Mechanical valves have a low incidence of reoperation, mostly for prosthetic dehiscence. Pannus development is the next frequent complication increasing with time since implant, therefore in this series it was related to old valvular models and tilting disk prosthesis, with longer follow-up. Acute thrombosis occurs significantly earlier than pannus formation. Despite shorter follow-up we are therefore confident that bileaflet prostheses are less prone to this complication and pannus is a rare early etiologic factor. Thrombosis has very high operative risk as compared to pannus, justifying the present trend to thrombolysate selected cases.

Relationship between magnitude of resection, complication, and prosthetic survival after prosthetic knee reconstructions for distal femoral tumors.

Abstract: Background and Objectives Limb-sparing surgery has become the preferred surgical treatment of malignant bone tumors The objective of this study was to evaluate factors that influence the morbidity and outcome of prosthetic knee replacement after resection of malignant tumors of the distal femur Methods Eighty-two patients who had a resection of malignant tumor of the distal femur and implantation of a segmental knee prosthesis (minimum follow-up, 2 years) were retrospectively reviewed Results Twenty-nine patients (35%) underwent 32 prosthetic revisions, 6 from perioperative wound complications, 13 from aseptic loosening, and 13 from other complications The 3-, 5-, and 10-year Kaplan-Meier prosthetic survival rates were 82%, 71%, and 50%, respectively On univariate analysis, patients who had more than 40% resection of the distal femur (P = 0010) and those who had all their vasti muscles resected (P = 0011) had significantly worse prosthetic survivals than the others On multivariate analysis, resection of more than 40% of the distal femur was a significant negative prognostic factor for prosthetic survival (P = 0017) Aseptic loosening was the primary cause of late prosthetic failure Differences in the magnitude of resection influenced prosthetic survivorship more than prosthetic design Conclusions In the distal femoral endoprosthetic replacement, higher short- and long-term complications were found after extensive resections Aseptic loosening was the primary cause of prosthetic failure J Surg Oncol 1999;70:109–115 © 1999 Wiley-Liss, Inc

Staphylococcus aureus prosthetic joint infection treated with prosthesis removal and delayed reimplantation arthroplasty.

Abstract: Objective To estimate in patients with Staphylococcus aureus prosthetic joint infection after total hip arthroplasty (THA) or total knee arthroplasty (TKA) the microorganism-specific cumulative probability of treatment failure after prosthesis removal and delayed reimplantation arthroplasty. Patients and Methods All patients with S aureus THA or TKA infection, according to a strict case definition, who were treated with prosthesis removal and delayed reimplantation arthroplasty at Mayo Clinic Rochester between 1980 and 1991 were identified. The study group comprised patients who were free of infection at the time of reimplantation arthroplasty. This cohort was followed up until treatment failure, infection with another organism, prosthesis removal, death, or loss to follow-up occurred. The Kaplan-Meier survival method was used to estimate the cumulative probability of treatment failure. Results Among 120 S aureus prosthetic joint infections treated with prosthesis removal during the study period, 38 episodes (22 THA, 16 TKA) in 36 patients met the study inclusion criteria. After a median of 7.4 years (range, 0.9 year-16.4 years) of follow-up, treatment failure occurred in 1 (2.6 %) of 38 episodes 1.4 years after reimplantation arthroplasty. The 5-year cumulative probability of treatment failure was 2.8% (95% confidence interval, 0%-8.2%). Conclusions These data suggest that prosthesis removal and delayed reimplantation arthroplasty is an effective treatment to limit the recurrence of S aureus prosthetic joint infection, provided there is no evidence of infection at the time of reimplantation arthroplasty.

Reoperation for failed prosthetic replacement used for limb salvage

Abstract: Patients with segmental bone and joint replacement prostheses because of tumors increasingly need revision surgery because of their long term survival. Between 1970 and 1990, 208 custom prosthetic replacements were performed for limb salvage in patients with tumors. Reoperations were required in 52 patients. The mean time to reoperation was 37 months. The reoperation procedures included 35 prosthetic revisions, 11 amputations, four arthrodeses, one vascularized fibular graft, and one open reduction and internal fixation of a fracture with supplemental bone graft. Functional assessment using the new Musculoskeletal Tumor Society scoring system was available for the 36 living patients, and their mean rating was 63% (18.9) at 12 years' mean followup. Of the 35 patients who received a new prosthesis, 12 (33%) patients needed a third operation at mean followup of 68 months. The probability of prosthetic survival in the group of 35 patients needing revision to the same or another prosthesis was 79% at 5 years and 65% at 10 years. The chance and frequency of needing reoperation increased as patients survived longer. Reoperations for tumor recurrence or infection usually resulted in amputation. Reoperation for failed initial segmental bone and joint prosthetic replacement is feasible and effective and can be done without jeopardizing subsequent patient and implant survival or without significantly affecting functional results compared with the values before reoperation.

Long-term study of quality and safety of osseointegration for the retention of auricular prostheses☆☆☆★

Abstract: The aim of this article is to describe the safety and quality of the osseointegrated implant technique for the retention of craniofacial prostheses, to present a protocol for collection of clinical data, and to discuss the impact of the procedure on the patient quality of life. A protocol was designed and used to study patients who had received auricular prostheses consecutively since 1979 at our department. The patients were asked to answer a questionnaire designed to describe symptoms and problems specific for someone wearing an auricular prosthesis. In total, 99 patients received 107 prosthetic ears (8 patients had bilateral defects) retained on 309 implants (2 to 4 implants/ear). Patients of all ages were represented, and only 9 discontinuities were reported. Most patients (95%) wear their prosthesis every day, in most cases more than 10 hours/day. The follow-up period ranged from 1 to 12 years, giving a total of 2624 postoperative observations of implants, with a 3% incidence of significant skin reaction. We conclude that the surgical technique for auricular prostheses retained on osseointegrated implants is simple and associated with a low rate of peroperative and long-term complications. It offers a high degree of stability and aesthetic satisfaction. (Otolaryngol Head Neck Surg 1999;121:133-43.)

Modular system for shaft prostheses

Abstract: With the invention a modular system for the mounting of shaft prostheses is shown which have a coupling which can be fixed within a predetermined angular range between the prosthesis stem and the prosthesis head, which can be fixed by an apparatus in the prosthesis stem Through a modular system with combinable stems and prosthesis heads of differing sizes for prostheses and test prostheses which are constructionally alike externally and in the position of the point of rotation, a variety of test prostheses and shaft prostheses arises The test prostheses have an apparatus in the prosthesis head which permit the fixing of the head in an ideal position with a controllable function in a stem inserted in a bone This position between the head and the stem is preserved when the test prosthesis is extracted and transferred to a mounting apparatus, in which a shaft prosthesis which is built up of analogous parts is brought into the same position and fixed

Laxity in posterior cruciate sparing and posterior stabilized total knee prostheses.

Abstract: Two series of consecutive total knee replacements were compared retrospectively: 118 HLS II posterior stabilized prostheses (Group 1) versus 138 HLS CP posterior cruciate ligament sparing prostheses (Group 2). Both implants were made by the same manufacturer. The prostheses had been inserted between 1989 and 1992. Mean followup was 4 years. The authors looked for evidence of laxity in the coronal and the sagittal planes, the correlation of laxity with other factors, and the effect of laxity on the objective and subjective outcome as measured with the Knee Society score. Group 2 had significantly more clinical and radiologic laxity. There was little difference between the two groups regarding the overall objective and subjective outcome; however, there was a significantly higher rate of excellent results in Group 1. Longer followup will be required to see whether the implants with laxity are at heightened risk for tibial component wear.

Extensible endoprostheses of the humerus after resection of bone tumours

Abstract: We carried out extensible endoprosthetic replacement of the proximal or total humerus in 18 children aged between six and 12 years, after resection of primary bone tumours mainly for osteosarcoma and Ewing’s sarcoma. In 11 patients we performed 44 lengthening procedures, with an average of two per child annually and a mean total extension of 29.9 mm per patient. We were able to achieve lengthening of the operated limb with few complications and a mean functional rating of 79.3% according to the Enneking system. Progressive lengthening of these prostheses does not adversely affect the overall function of the arm, and superior subluxation of the head of the prosthesis has not been a problem.

Tourniquet release for hemostasis increases bleeding. A randomized study of 77 knee replacements.

Abstract: We conducted a prospective, randomized study of 77 primary knee replacement operations on 75 patients (52 women), with a mean age of 71 years, to evaluate the effect of tourniquet release for hemostasis on blood loss and transfusion requirements. The operations were all done with spinal anesthesia and the use of a midline skin incision and medial parapatellar approach. In group I, the tourniquet was released for hemostasis before the wound was closed. In group 2, the tourniquet was first released after the wound was closed and a compressive dressing had been applied. The total intra- and postoperative blood losses were, on average, 858 mL (SD 443) in group I and 589 mL (347) in group 2 (p = 0.01). The median units of blood given and the postoperative decreases in hemoglobin values were similar in both groups. In a subgroup of 45 cementless prostheses, the 25 patients with prostheses allocated to group 1 lost 1022 mL (397) blood, compared to 646 mL (333) by the 20 patients with prostheses in group 2 (p = 0.01). Our findings speak against the efficacy of tourniquet release for hemostasis in knee replacement surgery.

Factors affecting femoral bone remodeling after cementless total hip arthroplasty.

Abstract: We performed a postmortem comparison of femurs from two patients who had bilateral cementless total hip arthroplasties with femoral prostheses of different stiffness implanted in their right and left hips. Radiographs of transverse sections of the four femurs demonstrated that all the prostheses were bone ingrown with the most ingrowth occurring distally where the porous coating contacted diaphyseal bone. In both patients, dual-energy x-ray absorptiometry analysis revealed that the femur implanted with the stiffer prosthesis had a 65% to 79% greater loss of proximal periprosthetic bone than the femur implanted with the more flexible prosthesis. One patient, however, had a dramatically greater total loss of bone from side to side than the other patient. In this patient, we believe that it was host factors more than the differences in stem stiffness that affected the bone-remodeling pattern. Although the two femurs with the stiffer prostheses had the greatest bone loss, the two femurs with the more flexible prostheses demonstrated radiographic signs of cantilever bending of the prosthetic stem and failure of proximal osseointegration. We are not aware of any other bilateral human postmortem analysis that so clearly illustrates the effect of stem stiffness on bone remodeling.

Nonunion after periprosthetic femoral fracture associated with total hip arthroplasty.

Abstract: Background: Nonunion after a periprosthetic femoral fracture associated with total hip arthroplasty occurs rarely. There is little information, to our knowledge, regarding the prevalence of this complication, its treatment, and the functional outcomes of treatment. The purpose of this study was to identify the patterns and frequency of nonunions of femoral fractures around total hip prostheses and to evaluate the results and problems associated with treatment of this complication in a consecutive series of patients. Methods: The study included twenty-three nonunions of periprosthetic femoral fractures in twenty-three patients with an average age of fifty-five years (range, twenty-two to eighty-five years) at the time of the initiation of treatment of the nonunion. Thirteen of the fractures occurred during or after a primary total hip arthroplasty, and ten occurred during or after a revision total hip arthroplasty. According to the classification system of Duncan and Masri, there were six B1 fractures (associated with a well fixed prosthesis), seven B2 fractures (associated with a loose stem), and ten B3 fractures (associated with very poor proximal bone). Ten patients were managed with revision to a long-stem prosthesis. Six patients had revision to a proximal femoral replacement prosthesis. A two-stage technique consisting of removal of the prosthesis and open reduction and internal fixation of the nonunion followed by reimplantation of the prosthesis was used in two patients. Two patients were managed initially with bone-grafting alone, and two patients were managed nonoperatively. One patient who had an infection at the site of the nonunion was managed definitively with resection arthroplasty. Results: The duration of clinical follow-up averaged 8.3 years (range, three months to twenty-three years), and that of radiographic surveillance averaged 7.0 years (range, eight months to seventeen years). Of the thirteen patients in whom an attempt to achieve union was made and for whom radiographs were available, nine eventually had bone-healing. Five of the twenty-three femora became infected and were treated with resection arthroplasty. Of the seventeen patients who had not had a resection arthroplasty for infection and for whom radiographs were available at the time of the most recent follow-up, eleven had a stable and well fixed implant and six had a loose implant as seen radiographically or had had a revision because of aseptic loosening. Seventeen patients had no or mild pain at the time of the most recent follow-up, but ten required two-handed support to walk. The overall complication rate was 52 percent (twelve of twenty-three patients). Conclusions: Nonunion of a femoral fracture associated with a total hip prosthesis is an infrequent problem. Treatment is difficult, with a high rate of complications and relatively poor functional outcomes. The data from this series must be interpreted with caution, as patients were managed over a period of three decades and many did not have the advantage of modern techniques of revision hip arthroplasty. Prevention of nonunion by optimum treatment of the initial fracture is most important. Treatment of a femoral nonunion about a total hip implant should be implemented on the basis of the status of the fixation of the prosthesis and the quality of the surrounding bone.

Biofilm Formation In Vivo on Perfluoro- Alkylsiloxane-Modified Voice Prostheses

Abstract: Objective To study the influence of perfluoro-alkylsiloxane (PA) surface modification of silicone rubber voice prostheses on biofouling. Design Placebo-controlled clinical trial. Setting Tertiary referral center, with specialization in head and neck cancer treatment. Patients Eighteen consecutive patients with laryngectomies and experienced in the use of a voice prosthesis who visited the outpatient clinic for prosthesis replacement. Material Eighteen partially surface-modified voice prostheses (3 with short-chain PAs [1 fluorocarbon unit] and 15 with long-chain PAs [8 fluorocarbon units]) were inserted via the patients' tracheoesophageal shunts and remained in place for 2 to 8 weeks. Intervention Replacement of the prostheses. Main Outcome Measures Evaluation of biofilm formation on short- and long-chain PA–modified and original silicone rubber surfaces on the esophageal side of the voice prosthesis. Results The planimetrical biofilm scores of the surfaces of all 3 short-chain PA–treated voice prostheses indicated more biofouling on the treated surfaces than on the untreated surfaces of the same prostheses. For the long-chain PA–treated prostheses, the planimetrical biofilm scores, as well as the numbers of colony-forming units per cm −2 for bacteria and yeasts, indicated less biofouling on the treated side than on the control side for 9 of the 13 prostheses that could be analyzed (2 were lost to analysis). Identical fungal strains, mainly Candida sp, were isolated from biofilms on each side of the esophageal flange. Conclusions Chemisorption of long-chain PAs by the silicone rubber used for voice prostheses reduces biofilm formation in vivo and therefore can be expected to prolong the life of these prostheses. Chemisorption of short-chain PAs by silicone rubber seems to have an adverse effect.

Evaluating the clinical performance of the Osseotite implant: defining prosthetic predictability.

Abstract: A 5-year prospective, multicenter study is in progress at four private dental practices to determine the cumulative implant survival rate and prosthetic outcome when using the Osseotite dental implant in posterior maxillary and mandibular areas. An interim evaluation after 34.4 months of study progress is presented. A total of 219 Osseotite implants were placed in 74 patients (34 women and 40 men with a mean age of 57.8 +/- 15.2 years) using a conventional two-stage surgical protocol and 3- to 6-month healing time. Subsequently, patients were restored with fixed or removable restorations. Nineteen of the 74 patients reported smoking an average of 13.2 cigarettes per day. Restorative treatments included 40 single-unit restorations; 53 splinted 2-, 3-, 4-, and 5-unit implant-supported maxillary and mandibular prostheses; 4 full-arch fixed maxillary prostheses; 1 mandibular fixed/detachable hybrid prosthesis; and 1 mandibular overdenture. The mean time from implant placement to second stage surgery was 6.2 +/- 2.0 months; from restoration and implant loading to the most recent follow-up evaluation was 20.9 +/- 6.8 months. Of the 219 implants placed, three posterior maxillary implants developed infections and were removed prior to second stage surgery. No implant failures occurred at second stage surgery or after implant loading. Using the Kaplan-Meier method, the cumulative implant survival rate was 100% for anterior implants and 98.4% for posterior implants at 28.5 +/- 5.7 months. The cumulative postloading implant survival rate was 100% for both anterior and posterior implants. The results of this study indicate that the Osseotite dental implant achieved a high rate of integration that remained stable during nearly 2 years of implant function. In addition, because no postloading implant failures have occurred, the Osseotite implant has provided a high level of prosthetic predictability.

Algorithm for the surgical treatment of malignant lesions of the proximal tibia.

Abstract: Complications are common among patients treated for malignant lesions of the proximal tibia and can be difficult to manage. This investigation was a retrospective review of 40 patients treated with total knee replacements after proximal tibial resections. Various reconstructive methods were used to fix the prosthetic stems, reestablish the extensor mechanism, and provide soft tissue coverage. Thirty-one patients had adequate followup to allow for review of prosthetic outcome (means, 78 months; range, 25-193 months). Seven patients died with less than 2 years followup, and two patients had postoperative acute infections treated by early amputation to allow chemotherapy to resume promptly. The overall 5-, 8- and 12-year event free prostheses survival rates were 62%, 33%, and 16%, respectively. Prognostic factors for prosthetic survival were analyzed (age, gender, type of excision, type of prosthesis, type of fixation, and percent of bone resected). None were statistically significant. Patients with less than 40% of the tibia resected had better prosthetic survival at 5 years. The durability of uncemented stem fixation exceeded that of cemented stems. Expected survival of prostheses after revision was 52% at 8 years. The major cause of limb loss was infection. Failure to reconstruct soft tissues satisfactorily caused most failures. Aggressive multistage management of infection is needed. Prosthetic knee replacement is most suitable for patients with cancers that require chemotherapy and for those patients who have short potential survival.

Cemented versus uncemented Thompson's prostheses: a functional outcome study

Abstract: One hundred and one elderly patients (90 female and 11 male) with a mean age of 83.5 years (range 69-100) were treated for intracapsular femoral neck fracture by Thompson's prosthesis. The prosthesis was fixed in the femoral shaft using Palacos cement in 23% and was inserted uncemented in 77%. We compared the following pre and postoperative variables in each group; mobility of the patient, their activity, walking aids and postoperative thigh pain. We also studied the pre and postoperative hip X-rays. Our patients did well in both groups. We conclude that there is no statistically significant difference between the variables in the two groups. Thompson's prosthesis can be inserted uncemented. Patients with radiological loosening of the prosthesis are not necessarily symptomatic. Intra and postoperative complications were similar to other published series of hip prostheses. The femoral neck osteotomy for Thompson's prosthesis can be performed safely well above the calcar femoris without detrimental complications. The original inter-trochanteric cut Thompson described is not necessary for acute fractures. This consequently makes revision of failed Thompson's prosthesis easier.

The long-term indwelling tracheoesophageal prosthesis for alaryngeal voice rehabilitation.

Abstract: Objective To analyze the initial experience at Oregon Health Sciences University, Portland, with the use of long-term indwelling tracheoesophageal voice prostheses. Design Retrospective case series. Setting Tertiary referral academic medical center. Patients Thirty patients undergoing speech rehabilitation after laryngectomy during a period of 18 months. Intervention Insertion of a long-term indwelling tracheoesophageal voice prosthesis. Main Outcome Measures Duration of use, complications. Results The mean duration of placement for a single prosthesis was 4.9 months (148 days), with a range of 14 to 330 days. Sixteen of the 30 patients encountered problems with leakage because of fungal colonization, the majority of which (15 of 16 cases) were solved with either oral or topical application of nystatin. Size matching in terms of prothesis length and tract length was critical, and problems of this nature were encountered in 11 of 30 patients. The incorporation of a second system of prostheses that offered an increased number of size options solved these problems in all of these patients. Ultimately, 27 of 30 patients were able to successfully wear these prostheses. Conclusions The indwelling tracheoesophageal voice prosthesis offers patients all the advantages of tracheoesophageal speech rehabilitation after laryngectomy without the inconvenience of frequent prosthesis changes. With careful attention to the details of fitting and care, it can be worn by the majority of patients successfully.

Prognostic factors during rehabilitation after shoulder prostheses for fracture

Abstract: PURPOSE To evaluate the role, the difficulties of rehabilitation and to diagnose the eventual surgical complications after shoulder prosthesis for 4-part fractures MATERIAL AND METHODS Forty three patients (46 shoulders) who underwent shoulder arthroplasty after fracture of the proximal humerus underwent rehabilitation and follow-up at a special reeducation center for an average of 3 months (1 to 6) There were 42 four-part fractures (with 22 fracture-dislocation) and 4 three-part fractures The patients were send by five different hospitals and have all been operated by senior surgeons Three types of implants were used: the Modular Shoulder prosthesis (27 cases), the Global prosthesis (2 cases), and the Aequalis prosthesis (17 cases) The rehabilitation followed the protocol recommended by Neer (recovery of passive joint movements, muscular strengthening and stretching) to which were added hydrotherapy, physiotherapy and occupational therapy Forty patients (43 epaules) were reviewed and radiographed with an average follow-up of 29 months (18 to 72 months) RESULTS The functional results were disappointing with a normalised Constant score of only 602 per cent and an average active elevation of only 96 degrees There appeared to be two factors which explained these poor results Firstly, the advanced age of the population (52 per cent older than 70) who was often poorly or non-motivated (22 per cent) and debilitated (21 per cent chronic alcoholics) and who had significant medical and neuro-psychiatric histories Secondly, incompletely resolved anatomical and surgical problems: damage to the circumflex nerve (65 per cent), early migration of the greater tuberosity (65 per cent), secondary migration with malunion (15 per cent) and/or nonunion (11 per cent) of the greater tuberosity Migration of the greater tuberosity should be suspected clinically in three circumstances: 1) in patients who have an abnormally painful shoulder in the immediate post-operative period (16 cases in our series); 2) when there is no progression (24 per cent) or regression (9 per cent) of active shoulder mobility after three months of correct supervised rehabilitation; 3) later, if there is a dissociation between active anterior elevation (deficient) and passive anterior elevation (preserved) DISCUSSION AND CONCLUSION The age and poor general condition of the patients as well as the difficulty of the surgical technique more than the rehabilitation, explain the disappointing results observed after shoulder prosthesis for four-part fractures The discrepancy between active and passive elevation suggests that limited motion is not caused by a stiff shoulder because of glenohumeral scarring but instead by weakness of the deltoid (because of axillary lesion) and/or of the external rotators (because of greater tuberosity migration) There is some discordance between the necessity to early mobilise the shoulder and the high rate of tuberosity migration

Long-term results of limb salvage with the Fabroni custom made endoprosthesis.

Abstract: In 1972 the authors began working on a limb amputation method using custom endoprostheses. Because of the biomechanical characteristics of these prostheses, good long term results have been achieved. The current study presents the analysis of 27 cases, including 11 total femoral replacements, with a followup between 10 to 24 years (median, 14.4 years), with an overall score of 75% using the International Symposium On Limb Salvage evaluation system. Analyzing this surviving group, the authors realize that proximal humerus and proximal femur prosthesis with total or partial joint replacement have better scores of prosthetic survival, limb function, and patient acceptance and the lowest rates of mechanical complications. However, the replacement involving the knee had more complications and worse scores. The authors conclude that the simplest prosthetic design implanted had the fewest intrinsic prosthetic complications. Reducing the stiffness of a prosthesis and increasing the range of movement of the joint involved decreasing the stress forces between the prosthesis and the bone. This may have contributed to the favorable outcomes reported in the series.