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Osteolysis caused by tibial component debonding in total knee arthroplasty.

Late failure of total knee arthroplasties usually results from ultrahigh molecular weight polyethylene wear or implant loosening. Early failure from osteolysis is uncommon. However, we treated a patient with a failed total knee arthroplasty from osteolysis that developed 2 years postoperatively. The failure was associated with tibial component debonding from the cement mantle with abundant cement and metal debris. Although there was some third-body debris in the ultrahigh molecular weight polyethylene insert surface, the insert wear was not extensive. Although abundant cement and metal debris were found in the periarticular soft tissues, no ultrahigh molecular weight polyethylene was seen in histologic specimens under polarized light. The osteolysis seems to have been caused primarily by debris generated from debonding and torsional motion at the tibial baseplate-cement interface rather than the bearing surface. Although this failure mechanism has been well recognized in cemented total hip arthroplasties, it has not been reported to be a substantial cause of failure in total knee arthroplasties.

Aged↗

Variability of landmark identification in total knee arthroplasty.

Virtual reality is new technology that is finding application in many facets of orthopaedics. We will describe an application of virtual reality in orthopaedic research. Component placement in total knee arthroplasty depends on identification of anatomic landmarks about the knee. We surmised significant interobserver variability occurs in the identification of landmarks of the distal femur used in total knee arthroplasty. The results tested in virtual space show that certain anatomic landmarks used in total knee arthroplasty are not reliable. The significance of this observation is that landmark identification, an integral component of computer-assisted surgical navigation in total knee arthroplasty, represents a source of method error in an otherwise accurate and precise computer-assisted technique.

Arthroplasty, Replacement, Knee↗

Early failure in total hip arthroplasty.

Although some patients experience a success rate greater than 90% after total hip arthroplasty, others require revision surgery within 5 years after the index procedure. The purpose of our study was to analyze the failure mechanisms in patients who had revision surgery within 5 years after index total hip arthroplasty. We retrospectively reviewed 824 revision total hip arthroplasties performed in 692 patients from 1986-2001. Seven hundred forty-five patients had adequate data. Two hundred ninety-one (39%) patients had revisions within 5 years after index arthroplasty. Ninety-six (33%) patients had revision surgery for instability, 88 (30%) for aseptic loosening, 41 (14%) for infection, 14 (5%) for osteolysis, 44 (15%) for failed painful hemiarthroplasties, and eight (3%) for periprosthetic fractures. Early revisions for aseptic loosening decreased from 38% in the early period to 24% in the current period, whereas revisions for instability increased from 9% to 42%. We were alarmed that 39% of the revisions at our institution were performed during the first 5 years after index surgery. Although improved fixation methods decreased early revisions for loosening, early revisions for instability increased substantially during the same time. Steps to avoid short-term failure must be taken.

Age Distribution↗

Radiographic prediction of intraoperative bone loss in knee arthroplasty revision.

UNLABELLED: A key challenge for orthopaedic surgeons performing revision total knee arthroplasty is the management of bone loss. The goal of our study was to test the validity of predicting bone loss from preoperative radiographs using two commonly utilized bone loss assessments: the Anderson Orthopaedic Research Institute and University of Pennsylvania systems and secondarily to assess the frequency and severity of bone loss in a prospective study of total knee arthroplasty revisions. Ninety-eight total knee arthroplasty revision patients were assessed and bone loss was detected in 76 (77.6%) patients preoperatively and intraoperatively. The validity of both systems was established. Agreement between preoperative and intraoperative Anderson Orthopaedic Research Institute classification was fair for the femur and good for the tibia. All University of Pennsylvania preoperative measures were correlated with intraoperative measures. Establishing valid and reliable preoperative systems of measuring bone loss facilitates planning of total knee arthroplasty revision and rehabilitation and meaningful comparisons between different series of patients and treatment protocols. LEVEL OF EVIDENCE: Diagnostic study, level I (prospective testing of previously developed diagnostic criteria on consecutive patients [with universally applied reference "gold" standard]). See Author Guidelines for a complete description of levels of evidence.

Adult↗

Extensor mechanism disruption after total knee arthroplasty.

UNLABELLED: Extensor mechanism disruption after total knee arthroplasty is a challenging complication for orthopaedic surgeons. The treatment options for repair include observation, direct primary repair, direct primary repair with synthetic ligament or autogenous tissue augmentation, or reconstruction with allograft tissue. A computerized systemic review and literature search was performed to identify the relevant literature on extensor mechanism disruptions associated with total knee arthroplasty. A comprehensive review of the literature and description of relevant treatment options and outcomes were performed using the information gained with the literature review. A multi-center prospective study on a consecutive series of patients recruited from the North American Knee Arthroplasty Revision (NAKAR) study was performed and data collected pre-operatively, intra-operatively, and post-operatively on patients that had a failed total knee arthroplasty using validated health related quality of life measures was analyzed. Six out of 290 patients in the study had extensor mechanism disruption and this group of patients had overall worse functional outcomes. The results of the study have solidified our knowledge that patients with extensor mechanism disruptions have worse functional outcomes and will need intensive management and rehabilitation. LEVEL OF EVIDENCE: Economic and decision analyses, level III (systematic review of level III studies). See Guide for Authors for a complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗

Minimally invasive revision total knee arthroplasty.

UNLABELLED: Exposure in revision total knee arthroplasty can be difficult. For example, eversion of the patella may require a number of procedures including vastus snips, V-Y turndowns, and tibial tubercle osteotomies. A minimally invasive approach further adds to exposure difficulties. We report a new approach for exposure during difficult revision total knee arthroplasties. A soft tissue envelope technique allows retraction of the patella and avoids eversion. This technique reduces the size of the incision, reduces quadriceps muscle damage, and enhances exposure. It is essential that appropriate instrumentation is used along with down sized femoral and tibial cutting blocks. We report all 17 revision knee arthroplasties using this technique including unicompartmental revisions, tibial component revisions, and femoral component revisions. Followup averaged 29 months (range, 24-39 months). We had one case of posterior retained cement after a full revision with no subsequent complications. One patient required an arthroscopic lateral release for patellar maltracking. Preliminary results are encouraging using improved instrumentation we find essential for enhanced exposure. We believe this a reasonable approach for selected total knee arthroplasty revisions. LEVEL OF EVIDENCE: Therapeutic study, level IV (retrospective case series). See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗

Revision hip arthroplasty for late instability secondary to polyethylene wear.

We evaluated the outcome of revision arthroplasty for polyethylene wear presenting as late dislocation. The computerized databases at two institutions were reviewed to identify all patients presenting with first time dislocation five or more years after total hip arthroplasty. Records and radiographs were then evaluated, and patients whose late dislocation occurred in the presence of greater than two millimeters of polyethylene liner wear with no other etiology for dislocation were identified. There were 22 patients with a mean age of 57.8 years at primary procedure. The average time from initial arthroplasty to dislocation was 9.0 years. Revision surgery to address polyethylene wear and instability was performed at a mean of 11.1 years (range 5.8 to 23 years). Revision surgery restored stability to eighteen patients (eighty-two percent). Polyethylene wear can and is associated with late dislocation after hip arthroplasty. Exchange of polyethylene lining of a metal backed implant or revision of the all polyethylene acetabular component can successfully address late instability in the majority of patients.

Adult↗

Epidemiology of dislocation after total hip arthroplasty.

Instability after total hip arthroplasty is an important complication. It usually occurs in the immediate postoperative period, but the risk also increases with time. There are numerous surgical treatment options, but they have relatively unpredictable outcomes. Numerous factors are associated with dislocation, but research has mainly focused on surgical factors. Epidemiological factors remain the subject of much debate. We aimed to establish the most significant epidemiological factors in Scotland and in particular the dislocation rate in neuromuscular conditions. The Scottish National arthroplasty nonvoluntary registry is based on SMR01 records (Scottish Morbidity Record) data. We analyzed the Scottish National Arthroplasty Project to find patients' dislocation rates up to 1 year postoperatively for surgeon volume, age, gender, previous surgery, diagnosis, and followup duration. There were 14,314 total hip arthroplasties performed from April 1996 to March 2004 with an annual incidence of dislocation of 1.9%. We found an association between rate of dislocation with age, surgical volume, and previous fracture. However, there was no increase in the rate of dislocation associated with gender or with diagnoses of stroke or Parkinson's disease. Our prognostic assessment of dislocation risk allows assessment for methods of reducing dislocation in high risk patients.

Age Distribution↗

Survival of medial unicondylar arthroplasties placed by one surgeon 1984-1998.

Unicondylar arthroplasty survival rates have varied widely. Implant- and patient-specific factors may be contributory. One surgeon placed 411 medial compartment arthroplasties of 12 designs from 1984 to 1998. In most cases, the fixed bearing tibial component was placed with cement and featured gamma-sterilized-in-air polyethylene and a metal backing. Tibial component initial thickness averaged 8.5 +/- 1.4 mm. Polyethylene shelf age averaged 1.3 +/- 1.2 years. Age and weight at arthroplasty averaged 67 +/- 8 years and 83 +/- 15 kg, respectively. Survival (no revision) at 9 years was 80%. Revision was more common in younger patients, in those with a thinner tibial component or longer polyethylene shelf age, and when some designs were used rather than others; weight and gender were not associated with revision. Nine-year survival improved to 94% when tibial component thickness was > 7 mm and polyethylene shelf age was < 1 year (154 knees). Per our experience, placement of a thin or shelf-aged gamma-irradiated-in-air polyethylene bearing into a young or active subject could explain most failures of unicondylar arthroplasties done in the 1980s and 1990s. Unicondylar patients of that era who were fortunate enough to avoid a thin or aged oxidation-prone polyethylene bearing probably have enjoyed superior outcomes.

Aged↗

Patella maltracking in posterior-stabilized total knee arthroplasty.

Maltracking of the patella component in total knee arthroplasty usually leads to complications such as subluxation, dislocation, fracture, excessive wear, or implant failure. After using a new posterior-stabilized total knee arthroplasty and a specific protocol for the patellofemoral articulation we determined the incidence of lateral retinacular release and patella complications. We retrospectively reviewed 255 consecutive primary posterior-stabilized total knee arthroplasties with an anatomic femoral component and a three-peg offset-dome patella. Component alignment was achieved using Whiteside's lines for the femoral component, the medial border of the tubercle for the tibial component, and previously reported techniques for the patella. Lateral release was performed in 15 knees (6.2%), most of which had excessive preoperative valgus (mean, 15 degrees). There were no reoperations for the patellofemoral joint at a mean followup of 3.7 years (range, 2-7 years). Two patients had asymptomatic osteonecrosis of the patella with complete radiolucent lines, and one patella fracture was treated with immobilization. We believe patella maltracking a largely avoidable problem in total knee arthroplasty. We found a low incidence of lateral retinacular release and patella complications using these components and this protocol for the patellofemoral articulation.

Aged↗

Biomechanical evaluation of the Total Facet Arthroplasty System: 3-dimensional kinematics.

STUDY DESIGN: An in vitro biomechanical study to quantify 3-dimensional kinematics of the lumbar spine following facet arthroplasty. OBJECTIVES: To compare the multidirectional flexibility properties and helical axis of motion of the Total Facet Arthroplasty System (TFAS) (Archus Orthopedics, Redmond, WA) to the intact condition and to posterior pedicle screw fixation. SUMMARY OF BACKGROUND DATA: Facet arthroplasty in the lumbar spine is a new concept in the field of spinal surgery. The kinematic behavior of any complete facet arthroplasty device in the lumbar spine has not been reported previously. METHODS: Flexibility tests were conducted on 13 cadaveric specimens in an intact and injury model, and after stabilization with the TFAS and posterior pedicle screw fixation at the L4-L5 level. A pure moment of +/-10 Nm with a compressive follower preload of 600 N was applied to the specimen in flexion-extension, axial rotation, and lateral bending. Range of motion (ROM), neutral zone, and helical axis of motion were calculated for the L4-L5 segment. RESULTS: ROM with the TFAS was 81% of intact in flexion (P = 0.035), 68% in extension (P = 0.079), 88% in lateral bending (P = 0.042), and 128% in axial rotation (P = 0.013). The only significant change in neutral zone with TFAS compared to the intact was an increase in axial rotation (P = 0.011). The only significant difference in helical axis of motion location or orientation between the TFAS and intact condition was an anterior shift of the helical axis of motion in axial rotation (P = 0.013). CONCLUSIONS: The TFAS allowed considerable motion in all directions tested, with ROM being less than the intact in flexion and lateral bending, and greater than the intact in axial rotation. The helical axis of motion with the TFAS was not different from intact in flexion-extension and lateral bending, but it was shifted anteriorly in axial rotation. The kinematics of the TFAS were more similar to the intact spine than were the kinematics of the posterior fixation when applied to a destabilized lumbar spine.

Adult↗

Midterm results of revision total elbow arthroplasty in patients with rheumatoid arthritis.

We retrospectively reviewed the clinical and radiographic results of 30 revision total elbow arthroplasties in patients with rheumatoid arthritis using original surface prostheses developed in our institution. We asked whether a surface prosthesis is a suitable option for reconstructing a failed surface total elbow arthroplasty in terms of reproducing clinical performance compared with other devices such as semiconstrained prostheses. All 30 failed total elbow arthroplasties were performed with various surface prostheses and revised with Dogo Onsen Hospital surface prostheses. The mean age of the patients at the time of surgery was 64.9 years (range, 44-83 years), and the minimum followup was 3 years (mean 6.7 years; range, 3-11 years). The Mayo elbow performance index improved from 42.3 preoperatively to 76.3 at last followup. Pain, stability, and function scores improved after revision surgery, but range of motion scores were unchanged. Our data indicate a surface prosthesis is a reasonable option for reconstructing failed surface total elbow arthroplasties in patients with rheumatoid arthritis.

Adult↗

Recentering the humeral head for glenoid deficiency in total shoulder arthroplasty.

Substantial posterior glenoid wear causing static posterior subluxation of the humeral head in patients with primary osteoarthritis has been described. Persistent humeral head subluxation after total shoulder arthroplasty can result in early polyethylene wear and glenoid component loosening. In our prospective cohort study, we hypothesized that in patients with posterior glenoid wear from osteoarthritis, static posterior decentering of the humeral head could be recentered during total shoulder arthroplasty by surgical correction of glenoid alignment in the transverse plane with soft tissue balancing. We performed total shoulder arthroplasties in 77 patients with primary osteoarthritis and a mean age of 67.6 years. The mean clinical and radiographic followup was 2 years (range, 1-7 years). Patients with preoperative posteriorly decentered humeral heads did not have posterior decentering develop postoperatively. Twenty patients (83.3%) had centered humeral heads and four patients (16.6%) had anterior decentering. Midterm results of total shoulder arthroplasties in shoulders with humeral head decentering caused by glenoid deficiency in the transverse plane showed correction of the decentering by lowering the high side or by bone grafting with soft tissue balancing can be well maintained.

Aged↗

Complications and outcomes of single-stage bilateral total knee arthroplasty.

BACKGROUND: A recent literature review by the senior authors of this study revealed that simultaneous bilateral knee arthroplasty is uncommon and controversial. Reported complications include myocardial infarction, deep venous thrombosis, pulmonary embolus, thromboembolic complications, pseudo-obstruction, postoperative ileus and death. This present study was designed to identify complications of single-stage bilateral total knee arthroplasty to compare with reports in the international literature. METHODS: A retrospective study of 40 cases of simultaneous total knee arthroplasty carried out by the senior authors at Wellington over the last 10 years, examined details of surgery, anaesthesia, preoperative and postoperative management to identify the occurrence of complications. Thirty-one patients completed an Oxford Knee Score, a EuroQuol-5 Dimension (EQ-5D) questionnaire and reported their experience of the bilateral procedure. RESULTS: Complications reported in the international literature did not occur in the patients studied. Complications that did occur included urinary retention, wound infections and oedema of the limbs or knees. The mean Oxford Knee Score was 20.79. In 2003 the New Zealand national mean for primary total knee arthroplasty was 23.35. The EQ-5D revealed high patient satisfaction and good functional status. CONCLUSIONS: While the outcomes and cost benefits of single stage bilateral replacement are established, the risk of complications remains. This study establishes the low complication rate associated with this procedure in the senior authors' hands, and documents the high patient satisfaction. The study demonstrates that, in selected patients, simultaneous bilateral knee replacement surgery can be performed with good outcomes without a definite increase in perioperative risk.

Adult↗

Multiparameter quantitative computer-assisted tomography assessment of unicompartmental knee arthroplasties.

BACKGROUND: Unicompartmental knee arthroplasty is a popular alternative to total knee replacement in selected patients. Component alignment has not yet been described by computer-assisted tomography (CAT) imaging techniques; these have been developed for total knee arthroplasty analysis. The aims of this study were to report two new technologies; a new unicompartmental knee arthroplasty system was radiographically assessed with a new CAT scan protocol. METHODS: In a consecutive cohort study, 60 knees were analysed by the 'UniCAT Protocol'. Patients were implanted with a unicompartmental knee arthroplasty system that uses a unique ligament tensor for femoral component alignment. The uniCAT protocol requires a long anteroposterior and lateral scout scan to measure limb alignment and component orientation. A spiral computer-assisted tomography at the knee is used to measure component rotation. The total scan time was 20 s with a calculated unshielded radiation dose of 1 mSv or less. RESULTS: The mechanical axis had a mean of 2.7 degrees varus. Femoral components were implanted with a mean of 0.37 degrees valgus and 1.3 degrees flexion. Tibial components were implanted with a mean 3.47 degrees varus and 5.1 degrees posterior slope. Femoral components were externally rotated a mean of 3.36 degrees, tibial components were externally rotated 6.59 degrees from the posterior tibia and 5.68 degrees from the transepicondylar axis. CONCLUSION: The UniCAT protocol uses less radiation than whole-limb spiral scans and is a method that can be used with all modern computer-assisted tomography machines. The coronal and sagital alignment results compare favourably with previous published reports without computer-assisted tomography. Component rotation has not previously been reported and its implications are yet to be defined.

Arthroplasty, Replacement, Knee↗

Weight changes and the risk of knee osteoarthritis requiring arthroplasty.

OBJECTIVE: To examine the effect of weight changes between 20 and 50 years of age on the risk of severe knee osteoarthritis (OA) requiring arthroplasty. SUBJECTS AND METHODS: Cases were 55-75 year old men and women (n = 220) having had knee arthroplasty for primary osteoarthritis at the Kuopio University Hospital in 1992-93. Controls (n = 415) were randomly selected from the population of Kuopio Province. Weight at the age of 20, 30, 40, and 50 years was collected retrospectively with a postal questionnaire. RESULTS: After adjustment for age, sex, history of physical workload, recreational physical activity, and previous knee injury, weight gain resulting to a shift from normal body mass index (BMI < or =25 kg/m(2)) to overweight (BMI >25 kg/m(2)) was associated with a higher relative risk of knee OA requiring arthroplasty than persistent overweight from 20-50 years of age, compared with those with normal relative weight during the corresponding age period. The odds ratios (OR) were 3.07 (95% confidence interval 1.87 to 5.05) for those with normal weight at the age of 20 years and overweight at two or three of the ages 30, 40 or 50 years, 3.15 (1.85 to 5.36) for those with overweight from the age of 30 years, and 2.37 (1.21 to 4.62) for those with overweight from the age of 20 years, respectively. CONCLUSION: In adult life, a shift from normal to overweight may carry a higher risk for knee OA requiring arthroplasty than does constant overweight.

Adult↗

Expression of epidermal growth factor and transforming growth factor alpha in interfacial membranes retrieved at revision total hip arthroplasty.

BACKGROUND: The interfacial membrane between bone and implant has been shown to be a key tissue in the process of aseptic loosening of total hip arthroplasty. The cells within the interfacial membrane produce numerous inflammatory mediators which, through complex mechanisms, cause periprosthetic osteolysis and aseptic loosening. Both epidermal growth factor (EGF) and transforming growth factor alpha (TGFalpha) have similar biological functions. They have been found to stimulate bone resorption. OBJECTIVE: To investigate the presence, cellular localisation, and extent of expression of EGF and TGFalpha in interfacial membrane retrieved from revision total hip arthroplasty and compare it with that in synovial membrane from primary total hip arthroplasty. METHODS: Ten interfacial membranes and 10 synovial membranes were stained with avidin-biotin-peroxidase complex for EGF and TGFalpha. The staining process was done using the Lab Vision Autostainer. The results were measured by a semiautomatic VIDAS image analysis system. RESULTS: Immunoreactivity for both EGF and TGFalpha was found in the endothelial cells of blood vessels, macrophages, and fibroblasts, both in interfacial membranes and synovial membranes. However, the number of EGF (980 (370)) and TGFalpha (1070 (360)) positive cells per mm(2) was greater in interfacial membranes than in the synovial membranes (220 (200), 270 (100); p<0.01). CONCLUSION: It is suggested that owing to their increased expression in interfacial membrane, EGF and TGFalpha may have an important pathogenetic role in stimulating periprosthetic bone resorption in aseptic loosening of total hip arthroplasty.

Adult↗

Ideas and innovations: radial approach to carpal tunnel release in conjunction with thumb carpometacarpal arthroplasty.

Several authors have written about the co-existence of thumb carpometacarpal arthritis and carpal tunnel syndrome, and 4% to 43% of patients undergoing thumb carpometacarpal arthroplasty also have a carpal tunnel release. Some authors advocate that carpal tunnel release and thumb carpometacarpal arthroplasty should be performed at the same time. We perform a combined thumb carpometacarpal arthroplasty and radial approach carpal tunnel release through a single incision. The purposes of this study are to (1) determine the safety of this approach and (2) evaluate the effectiveness of this approach in decreasing the pain and numbness observed prior to surgery. Eight patients had combined thumb carpometacarpal arthroplasty and radial approach carpal tunnel release. With an average follow up of 14 weeks, all patients reported an improvement in pain and numbness. No nerve injuries occurred, and no difficulty in wrist flexion was observed. One patient had pillar pain persisting at 19 weeks follow-up. One patient had basilar thumb pain at 19 weeks, though this was improved over pre-operative levels.

Adult↗