Michael H. Huo

Custom-designed femoral prostheses in total hip arthroplasty done with cement for severe dysplasia of the hip

A custom-designed femoral prosthesis was implanted with cement and a standard acetabular component was used to treat nineteen severely dysplastic hips in fourteen consecutively managed patients. Components that had been custom-designed with the use of plain radiography were used because the anatomical reconstructive goals could not be achieved with commercially available implants. These goals were to match the offset of the femoral head and the length of the lower limb with those on the normal side for patients who had unilateral involvement and to provide an average (thirty to forty-millimeter) offset with equal limb lengths for patients who had bilateral involvement. A retrospective clinical and radiographic analysis was performed. The diagnoses included coxa vara (one hip), congenital dislocation (twelve hips), achondroplasia (three hips), and spondyloepiphyseal dysplasia (three hips). The mean age at the time of the reconstruction was forty-nine years (range, twenty-two to seventy-three years), and the mean duration of follow-up was fifty-seven months (range, twenty-seven to 108 months). In five hips, bone-grafting of the acetabulum was needed to obtain superolateral coverage. The clinical result was excellent in eighteen hips and good in one. No revisions have been performed to date. Two femoral components were possibly loose radiographically. One was associated with a definite loosening of the acetabular cup. In addition, one other cup was possibly loose. There was a 100 per cent rate of survival if only a revision procedure was considered as a failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Metallic debris in femoral endosteolysis in failed cemented total hip arthroplasties.

A prospective study was undertaken to quantitate metallic and cement debris in 12 consecutive patients with femoral endosteolysis (FE) and aseptic loosening of a cemented total hip arthroplasty. The mean interval between primary and revision surgery was 9.6 years. The average time to onset of FE was 8.9 years. There were four stems each of cobalt-chromium (Co-Cr), stainless steel (SS), and titanium alloy. At revision, tissue was retrieved from FE, the femoral bone-cement pseudomembrane, and the joint pseudocapsule. Histology of these tissues was studied using light and polarized microscopy. Metal and barium levels were measured by atomic absorption spectrophotometry. A histiocytic reaction and particulate cement debris were seen in every case. Polyethylene wear debris was noted in 11 of 12 cases (92%), and metallic debris in four cases (33%). Detectable metal levels were found in the FE in all cases. Metal levels were on average 2.5 times higher in FE than in femoral pseudomembrane, and 4.2 times higher than in joint pseudocapsule. This difference was statistically significant for the Co-Cr and SS groups. Barium levels in areas of FE were on average 1.7 times and 42.4 times higher than in femoral pseudomembrane and joint pseudocapsule, respectively. The difference seen between the FE and the joint pseudocapsule tissue was significant for all three alloy groups. The authors data demonstrated higher metal and barium levels in FE than in the other tissue sites. Polyethylene and cement debris were noted in nearly every case. Cement, polyethylene, and metallic particulate wear debris may contribute to the pathogenesis and progression of FE.

Total hip arthroplasty in patients with diabetes mellitus.

Diabetes mellitus is a common disease. It affects multiple organ systems. Adverse effects of hyperglycemia on infection, fracture healing, and bone remodeling have been recently reported. This study was conducted to evaluate the clinical and radiographic results of 93 total hip arthroplasties in 78 consecutive patients with diabetes. All femoral components were cemented using contemporary cementing techniques. Prophylactic antibiotics were given in each case. The mean follow-up period was 4.1 years (range, 2-6.5 years). Ninety-six percent of the hips were rated excellent or good. Radiolucencies were observed in only 3.7% of the stems, while 22.2% of the cups showed radiolucencies. There was a 4% revision incidence. There was no postoperative infection in this series--a distinct improvement from previously reported series. However, complications remained high at 24.3%. The most frequent complication was urinary tract infection (14.2%). The most serious complication was myocardial infarction. The authors believe total hip arthroplasty can be safely performed in patients with diabetes, provided that adequate medical and follow-up evaluations are performed. The medium-term clinical and radiographic follow-up evaluations are not inferior to reported series in patients without diabetes.

Total hip arthroplasty in sickle cell hemoglobinopathy

Twenty-two arthroplasties were performed in 14 patients with sickle cell hemoglobinopathy (SCH). There were 15 primary and seven revision procedures; none were lost to follow-up evaluation. In the primary arthroplasty group, there were two deaths in patients whose implants were functioning well. The remaining 13 hips had a mean follow-up period of 4.8 years. Failure occurred in five of these 13 hips (38%), four due to aseptic acetabular loosening and one due to sepsis. In the revision arthroplasty group, at a mean follow-up period of 5.3 years, failure occurred in three hips (43%), one due to acetabular loosening, one due to femoral loosening, and one due to sepsis. Perioperative complication rates were high in both groups. Femoral intramedullary sclerosis and bone altered by marrow hyperplasia were associated with intraoperative technical difficulties as well as problems with achieving long-term component fixation. Though total hip arthroplasty provides the most reliable measure of effective treatment in SCH, it carries a high risk of complications and failure.

Intraoperative heparin thromboembolic prophylaxis in primary total hip arthroplasty. A prospective, randomized, controlled, clinical trial.

Venous thromboembolic disease remains the most common and potentially fatal complication after total hip arthroplasty (THA). Proximal femoral deep vein thrombosis (DVT) is especially prone to propagate and embolize. The authors hypothesis was that intraoperative intravenous heparin administration could reduce proximal DVT in THA. There were 286 patients who entered into a prospective, double-blind, randomized clinical trial at the authors institution between June 1988 and May 1990. All patients had unilateral primary THA under hypotensive epidural anesthesia. The epidural catheter was placed at least 60 minutes before heparin administration. Intravenous heparin was given during surgery only. All patients received aspirin twice daily (650 mg/day) after surgery. Detection of DVT was by contrast venography on Postoperative Day 6 or 7. The study was divided into three phases. There was four groups: control (intraoperative saline), 30 minutes (1000 U heparin at beginning of surgery followed by 500 U every 30 minutes), continuous adjusted (1000 U or 1500 U initial bolus followed by continuous heparin infusion maintaining anticoagulation at 30%-50% elevation from baseline), and fixed dose (1000 U bolus before hip dislocation, and 500 U bolus before femoral canal preparation). Proximal femoral DVT was effectively reduced from 9.1% in the control group to 1.7% in the heparin groups (1.7% in 30 minute, 1.6% in continuous adjusted, 1.7% in fixed dose) (p less than 0.02). The overall DVT rate was also significantly reduced from 24.3% to 10% (p less than 0.01). No adverse effects from heparin administration were noted. Postoperative drainage, hematocrit levels on Postoperative Day 2 and at discharge, and transfusion requirements were not significantly different among the groups. The current recommended protocol is 1000 U bolus five minutes before hip dislocation, followed by 500 U bolus five minutes before femoral preparation. This, in conjunction with hypotensive epidural anesthesia and postoperative aspirin, is effective in reducing proximal DVT to less than 2% in primary THA.

Intraoperative adjusted-dose heparin thromboembolic prophylaxis in primary total hip arthroplasty.

Intraoperative, fixed, intermittent, low-dose intravenous heparin prophylaxis has been reported to significantly reduce the incidence of thromboembolic disease from 24.3% to 8.3% after primary total hip arthroplasty (THA). This study examined the potential efficacy of adjusted-dose intraoperative heparin administration, keeping the activated clotting time at 30%-50% greater than normal. It was hypothesized that prolongation of clotting parameters in a uniform manner would further decrease the incidence of thromboembolic disease postoperatively. Sixty-one patients completed the protocol. The overall incidence of thromboembolic disease was 9.8%. Five patients had a positive postoperative venogram: four in the calf and one in the proximal deep thigh vein. One patient had a symptomatic nonfatal pulmonary embolus diagnosed by ventilation-perfusion scan. There were no complications related to heparin administration. This approach was therefore equally as effective as the fixed-dose regimen, and it further confirmed the efficacy and safety of an intraoperative heparin prophylaxis regimen. The extra efforts required to maintain a constant intraoperative level of anticoagulation did not prove advantageous over the simpler, fixed-dose regimen in reducing the incidence of thromboembolic disease after primary THA.

Wear debris in cemented total hip arthroplasty.

One of the most prevalent clinical problems in long-term follow up of total hip arthroplasty patients is loosening of prosthetic fixation. Factors contributing to mechanical failure of total hip reconstruction are complex and multiple. It has become increasingly apparent that wear debris from the prosthetic components may contribute significantly to this process. The authors summarize some of the current concepts concerning the detrimental effects of metallic debris in total hip arthroplasty.

Total Hip Replacement Following Prior Surgeries

Total hip replacement has been applied to salvage failures of previous hip surgeries. When total hip replacement is performed for failed previous hip surgeries other than an index total hip replacement, it is generally termed a conversion hip replacement. The various etiologies may include:

Use of cemented all-polyethylene and metal-backed acetabular components in total hip arthroplasty: A comparative study

The results of 115 primary total hip arthroplasties (97 patients) performed using the Charnley system and contemporary cementing techniques were reviewed. Fifty-five all-polyethylene cups and 60 metal-backed cups were used. The mean follow-up period was 84 months. No statistically significant difference was noted between groups for radiographic loosening and no cup has been revised to date. Survival analysis did not reveal a statistically significant difference between groups. Although all-polyethylene cups had significantly greater polyethylene thickness, no difference was noted for rate of wear. Increased loosening of the metal-backed cups was not observed. Polyethylene thickness is increased by the use of 22-mm heads and this may have accounted for the lack of difference in loosening rates of the all-polyethylene and metal-backed cups.