Retrieval analysis of squeaking alumina ceramic-on-ceramic bearings.

This multicentre study analysed 12 alumina ceramic-on-ceramic components retrieved from squeaking total hip replacements after a mean of 23 months in situ (11 to 61). The rates and patterns of wear seen in these squeaking hips were compared with those seen in matched controls using retrieval data from 33 'silent' hip replacements with similar ceramic bearings. All 12 bearings showed evidence characteristic of edge-loading wear. The median rate of volumetric wear was 3.4 mm(3)/year for the acetabular component, 2.9 mm(3)/year on the femoral heads and 6.3 mm(3)/year for head and insert combined. This was up to 45 times greater than that of previously reported silent ceramic-on-ceramic retrievals. The rate of wear seen in ceramic components revised for squeaking hips appears to be much greater than in that seen in retrievals from 'silent' hips.

Ceramic-on-ceramic versus ceramic-on-polyethylene bearings in total hip arthroplasty: Results of a multicenter prospective randomized study and update of modern ceramic total hip trials in the United States.

One reason why otherwise well-functioning total hip replacements have a finite service life is eventual aseptic loosening of the implants because of osteolysis induced by wear particles from the artificial bearing. Pain and osteolysis from wear debris can manifest even in the absence of aseptic loosening. Total hip replacements with ceramic-on-ceramic articulations have shown less wear both in vitro and in vivo. A randomized prospective clinical trial was conducted to compare the outcomes of ceramic-on-ceramic articulations to ceramic-on-polyethylene articulations. Two-year data are of interest because premature failures of ceramic femoral heads usually occur by this time interval. Of 500 patients enrolled in this trial, half received total hip replacements with alumina-on-alumina bearings, while the other half had ceramic-on-polyethylene bearings. At the two-year follow-up, 444 patients (217 study group and 227 control group) were available for review. The clinical and radiographic outcomes between the groups were comparable, and reflected the typical results of primary total hip replacements. No complications related to spontaneous failures of the ceramic bearings were observed at this early follow-up period. Further follow-up is needed to confirm these findings over the long-term, but the short-term safety of alumina ceramic bearings in hip replacements reported in other recent reports is further validated by our findings. (Hip International 2005; 15: 129-35).

Independent contribution of elevated-rim acetabular liner and femoral head size to the stability of total hip implants.

The use of an elevated-rim acetabular liner in total hip arthroplasty is widely accepted. We sought to determine quantitatively the amount of additional stability provided by the elevated-rim liner compared with the standard nonelevated liner. The stability of the hip with a 32-mm femoral head was compared with the standard 28-mm head. Our results show that a 15 degrees elevated-rim acetabular liner placed in the posterior quadrant increased hip stability by an additional 8.9 degrees of internal rotation. Similarly the 32-mm head provided 8.1 degrees of additional internal rotation. The increases were statistically significant (P<.0001). We did not encounter increased anterior dislocation intraoperatively. The findings of this study indicate that the 32-mm head may contribute to hip stability in primary total hip arthroplasty, and in instances in which a posterior approach is used, an elevated-rim liner placed in the posterior quadrant may contribute independently to hip stability.

Prevertebral abscess with extension into the hip joint.

We present a case of a paravertebral abscess with extension into the hip joint. The presumed conduit of infection in this case is the iliopsoas bursa, which has been shown to provide direct communication between the retroperitoneal space and the hip joint in up to 15% of cadaveric specimens. The patient was treated with emergent open irrigation and debridement of the hip joint, as well as percutaneous drainage of the prevertebral abscess. The patient remains minimally symptomatic at the 2-year follow-up.

The promising role of 18F-FDG PET in detecting infected lower limb prosthesis implants.

UNLABELLED: The purpose of this study was to evaluate the feasibility of using 18F-FDG and PET for the detection of infection associated with lower limb arthroplasty. METHODS: Seventy-four prostheses in 62 patients in whom infection was suspected after artificial hip or knee placement were studied with this technique. Images were obtained 60 min after an intravenous injection of FDG. The images were interpreted as positive for infection if tracer uptake was increased at the bone-prosthesis interface. A final diagnosis was made by surgical exploration or clinical follow-up for 1 y. PET results were compared with the follow-up outcome in all patients. RESULTS: The sensitivity, specificity, and accuracy of PET for detecting infection associated with knee prostheses were 90.9%, 72.0%, and 77.8%, respectively. The sensitivity, specificity, and accuracy of PET for detecting infection associated with hip prostheses were 90%, 89.3%, and 89.5%, respectively. Overall, the sensitivity was 90.5% and the specificity was 81.1% for detection of lower limb infections. CONCLUSION: FDG PET is a useful imaging modality for detecting infections associated with lower limb arthroplasty and is more accurate for detecting infections associated with hip prostheses than for detecting infections associated with knee prostheses.

Modern ceramic-on-ceramic total hip systems in the United States: early results.

In 1997, two manufacturers began Food and Drug Administration approved investigations of a ceramic-on-ceramic (alumina) articulation total hip replacement in the United States. Osteonics (Allendale, NJ) and Wright Medical Technology (Arlington, TN) enrolled more than 500 and 300 patients, respectively, when their studies ended in the middle part of 1998. The author presents detailed early results of the series by Wright Medical Technology. Three hundred thirty-three patients were enrolled in 11 centers around the country in a prospective series. All patients received the Transcend ceramic-on-ceramic articulation and have a minimum of 18 months followup with a range of 18 to 36 months. Harris hip scores increased on average from 44 to 97 points. Four patients underwent revision surgery; one for deep infection, one for early migration of the cup, one for dislocation, and one for liner malplacement. Overall, there were 42 complications. Seven were systemic and 35 were related to the total hip replacement. Four of the 35 complications were ceramic related and included three chipped liners and one eccentric seating of the cup liner. To date, no patient underwent revision surgery for aseptic loosening. Seven technical guidelines are suggested to enhance the quality of the intraoperative and postoperative results: a conservative femoral neck cut; horizontal cup placement (< 45 degrees); increased anteverted cup placement (> 20 degrees); use of trial liners; impaction of ceramic pieces; hand placement of the liner; and removal of osteophytes and/or part of the anterior wall of the acetabulum to avoid impingement. Alternate bearing articulations, particularly ceramics, have important technical aspects to be considered at the time of implantation to minimize intraoperative and postoperative complications. To date, there have been no postoperative fractures of the ceramic pieces in any of the completed or ongoing ceramic-on-ceramic investigations by all involved manufacturers. These preliminary results are satisfactory at this time. One can look to the future with cautious optimism.

Predonated autologous blood transfusions after total knee arthroplasty: immediate versus delayed administration.

Efforts to avoid complications associated with transfusion of allogeneic blood have increased the use of preoperatively donated autologous blood (PAB). A major controversy has arisen: Should the same criteria be used for transfusion of autologous as allogeneic red cells? This study prospectively and randomly compared giving PAB immediately after total knee arthroplasty (TKA), beginning in the recovery room or delaying a transfusion until the patient's hemoglobin had fallen to less than a 9.0 g/dL transfusion trigger point. The results show that patients who received immediate transfusion had fewer nonsurgical complications (P < .002). Because TKAs are associated with an average blood loss of 1,400 mL, we recommend that PAB be used in the immediate postoperative period, especially in the elderly, in whom the risk for cardiac or nonsurgical complications is inherently increased.

Revision total hip arthroplasty in patients with avascular necrosis.

This retrospective study compared the results of revision total hip arthroplasty (THA) in patients with avascular necrosis to patients with osteoarthritis. Twenty-two revision THAs (34 components) in 19 patients with avascular necrosis were compared with 35 revision THAs (55 components) in 31 patients with osteoarthritis. All of the procedures were performed by a single surgeon between 1981 and 1994, and all patients had a minimum of 2 years of follow-up. At the time of revision surgery, the average age was 54 years for the avascular necrosis patients and 67 years for the osteoarthritis patients (P=.002). Clinical and radiographic follow-up was performed for an average of 7 years (range: 2-12 years). Six (18%) components in the avascular necrosis group and nine (16%) components in the osteoarthritis group required re-revision for aseptic loosening an average of 7 years after the original revision (range: 2-11 years). Statistical analysis demonstrated no significant difference between the two groups in regard to the incidence of failure, time to failure, Harris Hip Score, and radiographic appearance. Contrary to expectations derived from the literature on primary THA, no difference was found between the outcome and survivorship of revision THA in patients with avascular necrosis and patients with osteoarthritis, despite a significant difference in age.

Total hip arthroplasty in patients with avascular necrosis of the femoral head: a 2- to 10-year follow-up.

One hundred twenty-three total hip arthroplasties were performed in 85 patients with osteonecrosis of the femoral head. There were 51 males and 34 females with an average age of 45 years. The average followup time was 4.6 years with a range of 2 to 10 years. All femoral stems and 71 sockets were fixed with acrylic cement. Fifty-two of the sockets used were placed without cement. The average Harris hip score improved from 45 points preoperatively to 92 points at the time of last followup. Of the 246 components used, 6 acetabular and 4 femoral prostheses in 7 patients have been revised (4%). Two components (0.8%) were revised for infection, 2 (0.8%) for repeated dislocation, and 6 (2.5%) for aseptic loosening. There is current radiographic loosening in 3 acetabular and 2 femoral components (2%). None of the noncemented acetabular components was either radiographically loose or revised. Within the subset of the 36 patients (52 hips) with a minimum 5-year followup (average, 6.6 years), 5 components (5%) were revised and 4 (4%) components are radiographically loose. The overall revision rate for cemented and hybrid hips at 2 to 10 years followup was 4%. The revision rate for hybrid hips alone was 2.5% in the entire series and 2% for hips with a minimum followup of 5 years. These results seem significantly better than previously reported. Using modern cement techniques and components, total hip arthroplasty can give excellent results in the young patient with avascular necrosis and may be the treatment of choice when reconstructive surgery is required.

Deep venous thrombosis after total joint arthroplasty. The role of compression ultrasonography and the importance of the experience of the technician.

We evaluated the influence of the expertise of the technician on the accuracy of compression ultrasonography as a screening test to detect postoperative deep venous thrombosis in patients who had had primary or revision arthroplasty of the hip or the knee. The study was performed in two phases on two groups of patients who were evaluated with both compression ultrasonography and conventional venography. All of the patients received prophylaxis for deep venous thrombosis. In the first phase of the study, adequate venograms and ultrasonograms were made for 126 extremities (121 patients). Venography demonstrated seven thrombi in the proximal veins. Only three ultrasonograms were considered positive. Ultrasonography had a sensitivity of 0 per cent because none of the seven proximal thrombi identified with venography were detected with ultrasonography. Three ultrasonograms were false-positive (that is, the ultrasonogram was positive and the venogram was negative), so the specificity was 97 per cent. The accuracy of compression ultrasonography was 92 per cent. Both tests were performed on a second group of eight-seven extremities (eighty-four patients). Proximal clots were detected with venography in five extremities. The ultrasonogram was positive for seven extremities, including the five in which a clot had been identified with venography. There were no false-negative and two false-positive results. In this phase of the study, ultrasonography had a sensitivity of 100 per cent, a specificity of 98 per cent, and an accuracy of 98 per cent. The only difference that was identified between the two groups of patients was the experience of the ultrasonography technician. It appears that the reliability of compression ultrasonography is directly dependent on the experience of the technician.

Osteonecrosis of the knee following laser-assisted arthroscopic surgery: a report of six cases.

We report six cases where significant postoperative pain persisted in individuals following arthroscopic surgery augmented with the use of lasers. Subsequent magnetic resonance images showed lesions with signal changes compatible with the diagnosis of osteonecrosis in areas directly addressed with laser energy.

Long term followup of thorough debridement and cancellous bone grafting of the femoral head for avascular necrosis.

From 1977 to 1982, 13 patients were diagnosed with avascular necrosis of the femoral head. The diagnoses were made with a combination of clinical exams, radiographs, tomograms, and Tc99 bone scans. One hip was classified as Ficat Stage I, 9 as Stage II, and 5 as Stage III. There were 11 male and 2 female patients with an average age at the time of surgery of 34 years. Idiopathic osteonecrosis was the final diagnosis in 10 patients, while 3 had a significant history of steroid use. The anterior neck was approached via Watson-Jones or Smith-Petersen approach. A window was then made in the femur at the head/neck junction. Drills, burrs and curettes were utilized under image intensification to perform a thorough debridement of all sclerotic bone. Cancellous bone was harvested from the ipsilateral iliac crest and was packed tightly into the femoral head to the subchondral plate. The cortical window was replaced. In 3 patients a gluteus medius pedicle flap was also utilized to augment the blood supply to the bone graft. This approach provided the access necessary to debride all dead and sclerotic bone. Healing and support of the subchondral plate were subsequently augmented with tightly packed cancellous bone graft. The patients were followed for 10-15 years (mean, 12 years). Two (13%) have since gone on to revision with total hip arthroplasty. The others (87%) remain essentially symptom free with minimal progression of osteoarthritis. There were no infections, femoral neck fractures, or thromboembolic events. Two patients with gluteal pedicle flaps developed ectopic calcification. Thorough debridement and cancellous bone grafting in patients with avascular necrosis of the femoral head is an effective procedure in young patients with Stage II or Stage III disease that will delay, if not prevent, the progression of osteoarthrosis and subsequent total hip arthroplasty.

Carotid hemorrhage: a complication of peritonsillar abscess.

Carotid hemorrhage secondary to peritonsillar abscess occurs infrequently today because of the effectiveness of antibiotic therapy. When it does occur, however, emergency physicians unfamiliar with such a complication may have difficulty making its diagnosis and instituting appropriate therapy. Prevention is the easiest way to treat septic erosion. Abscesses are treated best with penicillin or, in the allergic patient, clindamycin followed by incision and drainage. Once the abscess has eroded into the carotid artery, it usually must be tied off to control the subsequent massive bleeding.