PubMed Health⌕ Search

Biomedical subjects

W J Hozack

Publications and source records attributed to W J Hozack.

67 records · Page 4Linked to original sources
PubMed1991

Clinical and roentgenographic evaluation of hydroxyapatite-coated and uncoated porous total hip arthroplasty: a preliminary report.

Sixty osteoarthritic patients undergoing primary uncemented total hip arthroplasty were matched for age and weight and randomized into one of four groups with respect to implant coating and postoperative protected weight-bearing status: group 1, hydroxyapatite, 12 weeks; group 2, uncoated, 12 weeks; group 3, hydroxyapatite, 6 weeks; group 4, uncoated, 6 weeks. Tantalum spheres were implanted periprosthetically into the femur at the time of arthroplasty, thus providing constant references for stereoscopic radiographs. Patients were then evaluated over a 1-year period with clinical examination, plain radiography, and roentgen stereophotogrammetric analysis (RSA). Clinical evaluation using Charnley scoring showed no significant preoperative or postoperative intergroup differences, whereas visual analog testing noted less thigh pain with hydroxyapatite-coated stems at 12 weeks and 6 months follow-up. Plain radiographic analysis produced no significant differences, with no instability detected and bony ingrowth noted uniformly in all groups. The preliminary stereographic evaluation showed migration in all groups, but there were no significant differences between coated and uncoated stems or 6-week and 12-week partial weightbearing protocols. The Charnley, plain radiographic, and preliminary stereogrammetric evaluations all suggest that migration is unaltered by enhanced surfaces and that early unprotected weightbearing does not jeopardize implant fixation regardless of coating design. The lower incidence of visual analog thigh pain with the hydroxyapatite-coated stems, however, may be a reflection of bony ingrowth and as such add some validity to the theoretical advantages of enhanced surface prostheses.

Aged↗
PubMed1990

Survivorship analysis of 1,041 Charnley total hip arthroplasties.

Survivorship analysis of 1,041 cemented Charnley total hip arthroplasties performed as a primary procedure revealed a probability of component survival at 10 years of 92%; the probability of acetabular cup survival was 99% and of femoral component survival was 96%. Three-zone acetabular demarcation was present in 16% of cases, as was migration of the cup greater than 5 mm. However, the acetabular revision rate was 1.65%, confirming the long-term clinical durability of the 22-mm internal diameter cup. Radiographic evidence of definite femoral component loosening was present in 9.6% and high-grade femoral bone-cement demarcation was present in 3.5%. The isolated femoral revision rate was 1.8%. Based on detailed survivorship analysis, a high-risk group of patients was identified for component failure and for femoral component loosening (radiographic). These patients were male, young (less than 50 years), heavy (greater than 170 pounds), and active (not Charnley class C). Given these findings, it is difficult to justify the widespread use of noncemented total hip systems, except in identifiable high-risk patients.

Age Factors↗
PubMed1990

Popliteal aneurysm after total knee arthroplasty. Case reports and review of the literature.

Vascular complications after total knee arthroplasty include arterial occlusion, arterial severance, arteriovenous fistula, and arterial aneurysm. Both a false aneurysm and a true aneurysm of the popliteal artery are described. The false popliteal aneurysm resulted from direct surgical trauma and required excision and repair. The true popliteal aneurysm was unsuccessfully treated with excision, transfemoral thrombectomy, and bypass surgery. Many of the vascular complications after total knee arthroplasty may be preventable and the following prudent guidelines are suggested. Careful preoperative evaluation is critical, including past medical history, palpation of pedal pulses, and review of radiographs to identify abnormal calcification in the vessels. Vascular consultation may be necessary. Should a vascular complication occur, immediate intervention with the advice and assistance of a vascular surgeon is imperative.

Aged↗
PubMed1990

A prospective assessment of nutritional status and complications in patients with fractures of the hip.

A group of 40 consecutive patients with hip fractures were studied and confirmed to have a high incidence of protein-calorie malnutrition. The prospective nutritional assessment performed for this study included: serum albumin, serum transferrin, anthropometric measurements, skin testing for delayed hypersensitivity, total lymphocyte count, and a 24-h urine collection for metabolic and nitrogen balance determinations. At 3 months after their hip fracture, 37.5% returned to their premorbid ambulatory status; 42.5% sustained a decrement in their ambulatory status or independence; 12.5% died; 7.5% were lost to follow-up. Of the nutritional parameters studied, albumin was significantly associated with mortality (p = 0.004). Considering those patients with an albumin less than 3.0, a mortality rate of 70% was observed in follow-up (maximum of 11 months), compared with a mortality rate of 18% in patients with an albumin greater than or equal to 3.0. It is concluded that the serum albumin has value as a nutritional index without specialized nutritional parameters, and that a more aggressive approach to nutritional support is needed for the hypoalbuminemic patient with a hip fracture, particularly for those with a serum albumin below 3.0.

Aged↗
PubMed1990

Long-term survival of the Charnley low-friction total hip arthroplasty.

A survivorship analysis of 1,151 Charnley low-friction total hip arthroplasties performed as a primary procedure showed the following 15-year failure probabilities: hip revision 13%, cup revision 8%, femoral revision 12%, radiographic femoral loosening 13%, and radiographic cup loosening 49%. Pain scores diminished gradually with time so that at 15 years, the probability of a Charnley pain score less than 5 was 70%. The data suggest that the Charnley low-friction hip arthroplasty has a finite life span.

Adolescent↗
PubMed1990

Clinical and radiographic results with the Trilock femoral component--a wedge-fit porous ingrowth stem design.

Eighty-one cementless Trilock (Depuy, Warsaw, IN) femoral components were observed for 2 to 6 years. The following end points were examined: revision (none), pain score less than 5 (six patients), and radiographic settling greater than 5 mm (three patients). Four patients (5%) had thigh pain at follow-up. No complete radiopaque lines could be identified around the porous surface of the femoral components. By any standard, the wedge-fit tapered cementless femoral design is successful. As the follow-up period lengthens, a survivorship analysis can be done to assess the long-term potential of the Trilock design.

Adult↗
PubMed1989

Femoral neck fractures. A biomechanical study of a new form of internal fixation using multiple telescoping variable length compression screws.

Biomechanical tests of a new method of fixation for intracapsular hip fractures compared with other types of mechanical fixation were investigated under one specific loading condition. Human femora fixed in formalin were classified by the Singh index for degree of osteoporosis. Specimens of Grade III or less were grouped as osteoporotic, and Grade IV or greater, normal. Both normal and osteoporotic bones were tested. A transverse osteotomy in the subcapital region was fixed by one of two techniques: (1) Asnis screws (AS) or (2) variable length telescoping compression screws (VLCS). Each specimen was roentgenographed after fixation to assess the placement of the devices and reduction. Each femur was held in an angle vise that was placed on rollers on a table mounted on the servohydraulic testing machine. Compression was applied at a constant displacement rate of 10 mm per second to failure. Load and displacement were monitored; specimens were photographed and roentgenographed after failure. In osteoporotic bone, the VLCS provided yield and ultimate load values several times greater than those of the AS. Resistance to combined compression varus loading was significantly higher with the experimental system in osteoporotic bone. In normal bone there was no significant difference between the two systems.

Biomechanical Phenomena↗
PubMed1989

The patellar clunk syndrome. A complication of posterior stabilized total knee arthroplasty.

Patellofemoral pain due to an unusual suprapatellar fibrous nodule developed in three patients after posterior stabilized total knee arthroplasty. Each patient had a "catch" or "clunk" associated with pain on extension of the knee. At revision, a prominent fibrous nodule was found at the junction of the proximal patellar pole and the quadriceps tendon. The pathogenesis of this proximal fibrous nodule may involve impingement of the anterosuperior edge of the intercondylar notch area of the femoral component into the proximal quadriceps tendon or may involve impingement of the patellar prosthesis itself on the quadriceps tendon. Roentgenographic examination revealed an abnormally proximal placement of the patellar prosthesis on the patella. Surgical removal of the fibrous nodule resolved the symptoms. Revision of the patellar prosthesis may be necessary.

Aged↗
PubMed1988

Two-stage reimplantation of septic total knee arthroplasty. Report of three cases using an antibiotic-PMMA spacer block.

The management of an infected total knee implant is a major challenge to the orthopaedic surgeon. This article reviews the use of antibiotic-PMMA spacer block in two-stage reimplanation of septic total knee arthroplasties. In addition to serving as an antibiotic delivery system between the time of component removal and reimplantation, the antibiotic-impregnated spacer block imparts mechanical stability to the joint and decreases the morbidity during the period before reimplantation. This temporary "interposition arthroplasty" facilitates the patient's ambulation and also simplifies dissection at the time of reimplantation. Furthermore, osteoporotic bone at the time of resection becomes firm, good-quality bone by the time of reimplantation.

Aged↗
PubMed1988

The treatment of patellar fractures after total knee arthroplasty.

Based on 21 patellar fractures after total knee arthroplasty, the authors found that nondisplaced fractures of the patella following total knee arthroplasty are best treated nonoperatively, that displaced fractures with no extensor lag can adequately be treated nonoperatively, and that displaced fractures with an extensor lag present have poor results with operative treatment. Fragment excision should be considered for displaced distal pole fractures with patellar tendon disruption, and patellectomy should be considered for failures of all other treatments.

Aged↗
PubMed1988

The effect of early bladder catheterization on the incidence of urinary complications after total joint replacement.

A prospective, randomized study was performed in 54 female total arthroplasty patients to determine whether straight catheterization in the recovery room might reduce the incidence of postoperative urinary infection, urinary retention, and urinary catheterization. Thirty-one patients were straight catheterized in the recovery room; 23 were not. Overall, 13% of the patients developed a urinary tract infection postoperatively, 60% of the patients required at least one catheterization, and 13% of the patients required a Foley catheter. No beneficial effect of straight catheterization in the recovery room after arthroplasty was demonstrated.

Aged↗
PubMed1985

Fracture healing in the rabbit fibula when subjected to various capacitively coupled electrical fields.

The effect of capacitively coupled electrical stimulation on the healing of midshaft transverse osteotomies of the rabbit fibula is assessed roentgenographically, mechanically, and histologically. The results show that a dose-response curve for capacitive coupling and fracture healing exists and that a 220 mV, 250 microA, 60 kHz applied electrical signal (0.33 V/cm internal electric field) is the most effective signal for fracture stimulation in this model.

Animals↗