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Biomedical subjects

William J Hozack

Publications and source records attributed to William J Hozack.

At least 19 recordsLinked to original sources
PubMed2007

Clinical experience using a minimally invasive surgical approach for total knee arthroplasty: early results of a prospective randomized study compared to a standard approach.

There has been recent attention concerning minimally invasive techniques for knee arthroplasty. It is not clear whether these complicated techniques can be reproduced across multiple centers and for all surgeons. This prospective, randomized, multicenter study was carried out to assess safety and efficacy of a minimally invasive total knee arthroplasty. The study consisted of 80 knees. There were no differences in blood loss, operative time for completion of surgery, infection, and ultimate wound healing. There were 4 knees with delayed wound healing in the minimally invasive surgical technique group versus 1 in the standard group, which did not affect outcome. Early clinical and radiographic results were also indistinguishable. At 12 weeks follow-up, there was no difference in mean Knee Society objective and functional scores. In summary, in this study, minimal incision total knee arthroplasty demonstrated no improvement over a standard approach.

Aged↗
PubMed2007

Can epidural anesthesia and warfarin be coadministered?

Epidural hypotensive anesthesia can, in addition to imparting numerous intraoperative benefits, provide excellent postoperative pain control for patients having joint arthroplasties. However, because of the risk of epidural hematoma, epidural anesthesia is not coadministered with anticoagulation in some centers. We retrospectively ascertained, by chart review, the incidence of epidural hematoma in 11,235 patients having 12,991 knee arthroplasties at our institution who received oral anticoagulation and epidural anesthesia for their surgery. Warfarin was administered on the day of surgery. With the exception of 212 patients, the epidural catheter was removed within 48 hours of surgery. Based on clinical examinations, we detected no epidural hematomas. For 1030 patients (1038 knees) whose charts were reviewed in detail, the mean international normalized ratio at the time of removal of the epidural catheter was 1.54 (range, 0.93-4.25). We identified no other complications related to the coadministration of epidural anesthesia and warfarin. Although administration of epidural anesthesia in patients with coagulopathy can be detrimental, we recognized no cases of epidural hematoma causing neurologic symptoms in patients receiving controlled oral anticoagulation after total knee arthroplasty.

Anesthesia, Epidural↗
PubMed2007

Total joint arthroplasty: When do fatal or near-fatal complications occur?

BACKGROUND: With the recent trend toward minimally invasive total joint arthroplasty and the increased emphasis on faster recovery and shorter hospital stays, it has become increasingly important to recognize the timing and severity of the various complications associated with elective total joint arthroplasty to ensure that early patient discharge is a safe practice. METHODS: We evaluated the systemic and local complications associated with primary unilateral lower-extremity arthroplasties performed during one year in 1636 patients. A total of 966 patients had a primary total hip arthroplasty, and 670 had a primary total knee arthroplasty. All complications that occurred in the hospital and for six weeks following the index surgery were recorded. The circumstances leading to the complications and the details of the therapeutic intervention for each complication were recorded. Analyses were performed to predict the factors that predispose patients to serious complications. RESULTS: One patient (0.06%) in the cohort died during the hospital stay. There were a total of 104 major (life-threatening) complications, including cardiac arrest (one), tachyarrhythmia (thirty-three), pulmonary edema or congestive heart failure (ten), myocardial infarction (six), hypotensive crisis (four), pulmonary embolus (twenty-five), acute renal failure (fourteen), stroke (six), bowel obstruction or perforation (three), and pneumothorax (one). There were seventeen major local complications. Ninety-four (90%) of the major complications occurred within four days after the index surgery. Although older age, increased body mass, and preexistent comorbidities were important predisposing factors for serious medical complications, 58% of the patients who had life-threatening complications develop had no identifiable predisposing factors. CONCLUSIONS: This study demonstrated that most of the complications of lower-extremity total joint replacement occur within the time-frame of the typical hospital stay. Given the serious nature of some of these complications and the inability to identify many of the patients who may be at risk, we caution against early discharge of patients from the hospital after elective total joint arthroplasty in the lower extremity.

Adolescent↗
PubMed2006

Femoral perforation complicating contemporary uncemented hip arthroplasty.

This case series reports on 4 patients in whom intraoperative penetration of the femoral cortex occurred and went unrecognized on routine postoperative radiographs. This case series highlights some important points. Femoral cortex penetration can and does occur with uncemented hip arthroplasty and is likely to occur when surgical exposure is difficult and inadequate (such as in patients with severe obesity) or some form of proximal femoral deformity exists (such as patients with achondroplasia). Extra diligence should be exercised to avoid this complication in the high-risk patients, and adequate 2-plain radiographs may need to be ordered intraoperatively if such complication is suspected.

Achondroplasia↗
PubMed2006

Total knee arthroplasty using computer-assisted navigation in patients with deformities of the femur and tibia.

Anatomic aberrations of the femur and tibia secondary to trauma, congenital defects, and prior surgery present challenges for the reconstructive knee surgeon because of an altered mechanical axis and distorted anatomic landmarks. Five patients with arthritis of the knee and extra-articular femoral and/or tibial deformity, retained hardware, or intramedullary (IM) implants underwent total knee arthroplasty using a computer navigation system. The navigation system obviated the need for an IM guide, and the normal mechanical axis of the patients was restored. Extensive dissection for hardware removal or osteotomy was not necessary in these patients. In these 5 cases, a navigation system proved to be an effective tool for restoration of limb alignment in the presence of significant extra-articular deformities and/or IM hardware. Thus, it provides an alternative approach to the traditional IM instrumentation for treating these patients in an effective manner.

Aged↗
PubMed2006

The effect of knee component design changes on range of motion evaluation in vivo by a computerized navigation system.

Although acceptable for most patients, the range of motion obtained by traditional knee replacements may not be enough for certain patient populations. Modified knee designs have been introduced with the aim of increasing knee range of motion. Using a computerized navigation system, the effect of a modified total knee design on knee range of motion was evaluated in 30 knees. The Non-Restrictive Geometry knee system was found to provide a significant increase in mean flexion and overall range of motion of the knee compared with the Scorpio Flex knee system (P = .02). This confirms that changes in knee component design may result in improved range of motion.

Adult↗
PubMed2006

Simultaneous primary total hip arthroplasty and contralateral revision hip arthroplasty: role for use of femoral head autograft.

We report the outcome of revision hip arthroplasty for patients with acetabular bone loss in whom the femoral head retrieved from arthritic contralateral hip during the same anesthesia was used as autograft for acetabular reconstruction. Thirty-two hips in 16 patients with a mean age of 63.8 years (range, 43-79 years) were followed for an average of 3.5 years. All primary arthroplasties were successful. Evidence of autograft incorporation was found in all except 2 patients. The acetabular component failed and required revision in the latter 2 patients. The use of femoral head autograft in a select group of patients with symptomatic arthritis of hip and a failed prosthetic hip with severe bone loss in the contralateral side is a viable option. However, this technique should not be applied to acetabular reconstructions in which protected weight-bearing in the postoperative period may be necessary.

Adult↗
PubMed2006

Ninety-day mortality after bilateral hip arthroplasty.

Despite lack of any studies, to our knowledge, bilateral total hip arthroplasty (THA) is believed to carry higher perioperative mortality. The purpose of this study is to investigate the incidence of mortality within 90 days of bilateral THA in a major urban medical center. The incidence of 90-day mortality after 1-stage bilateral THA performed in 707 patients between 1995 and 2004 was evaluated. A detailed analysis of our database was performed to determine which bilateral THA patients died within 90 days of surgery. Every living patient who had undergone bilateral hip arthroplasty was contacted. One patient (0.14%, 1/707) died within 90 days of 1-stage bilateral THA. The patient developed spontaneous retroperitoneal hematoma requiring massive transfusion. The patient died of multisystem failure 35 days after undergoing bilateral THA. One-stage bilateral uncemented THA performed in a select group of healthy and young patients carries an acceptable risk.

Adolescent↗
PubMed2006

One-stage bilateral total hip arthroplasty compared with unilateral total hip arthroplasty: a prospective study.

It is believed that patients undergoing 1-stage bilateral joint arthroplasty are at higher risk for developing cardiopulmonary and possibly other complications. The aim of this prospective matched study was to evaluate and compare the morbidity profile of patients undergoing 1-stage bilateral uncemented total hip arthroplasty (BTHA) vs unilateral uncemented THA (UTHA). One hundred consecutive patients undergoing 1-stage bilateral THA (50 patients, 100 hips) and unilateral THA (50 patients) were recruited and prospectively followed. There were no statistically significant differences in 90-day mortality, individual major (BTHA, 8%; UTHA, 10%) or minor (BTHA, 20%; UTHA, 26%) complications between the 2 groups. Bilateral THA patients required more autologous and allogenic blood transfusion and had lower hemoglobin at discharge than UTHA patients. Patients undergoing BTHA should expect a slightly higher incidence of complications related to postoperative anemia.

Adolescent↗
PubMed2006

Hip arthroplasty with minimally invasive surgery: a survey comparing the opinion of highly qualified experts vs patients.

In recent years, there has been an increasing debate regarding the possible role of minimally invasive (MIS) total hip arthroplasty (THA). We conducted a questionnaire survey of the Hip Society members and compared the responses of the surgeons with those of patients who were being considered for THA. 80% of surgeons who completed the survey admitted to performing MIS THA, of whom two thirds defined MIS as small incision. Of surgeons, 74% had encountered some complication related to MIS THA; 67% of patients had not heard of MIS THA. The knowledge regarding MIS THA expressed by 80% of patients was either inaccurate or not substantiated by any studies. This survey highlights the inadequacy of our current understanding of MIS THA and lack of education on the part of the patients.

Arthroplasty, Replacement, Hip↗
PubMed2006

A double offset broach handle for preparation of the femoral cavity in minimally invasive direct anterior total hip arthroplasty.

A direct anterior approach is in use for minimally invasive total hip arthroplasty. This approach uses an intermuscular and internerval plane between the sartorius, rectus femoris, and tensor fasciae latae. Although preparation of the acetabulum and implantation of the acetabular component is an easy task with the available instruments, preparation of the femoral canal through this single incision is more demanding. Instrumentation of the femur involves careful preparation of the dorsal capsule, positioning of the operated leg, and leverage of the femur. A broach handle with lateral and anterior offset for the direct anterior approach has been developed to reduce the need for leverage of the proximal femur for preparation of the cavity.

Arthroplasty, Replacement, Hip↗
PubMed2006

Periprosthetic fractures after total knee arthroplasties.

UNLABELLED: The management of periprosthetic fracture around the knee remains a challenging problem. The objective of this article was to review the general concepts, treatment algorithms, and the overall treatment outcomes of femoral and tibial periprosthetic fractures after total knee arthroplasty. This article aimed to highlight the deficiencies of the current classification systems that fail to provide a guideline for selection of appropriate treatment options. We proposed a new classification system for periprosthetic femoral fractures that takes into account the status of the prosthesis, the quality of distal bone stock, and the reducibility of the fracture. Type I fractures are those occurring in patients with good bone stock with the prosthesis being fixed and well positioned. Type IA fractures are either nondisplaced or easily reducible and can be treated conservatively. Type IB fractures are irreducible and require reduction and internal fixation. Type II fractures are defined as those occurring also in patients with good bone stock and being reducible, but either the components are loose or malpositioned. These fractures are treated by revision arthroplasty. Type III fractures are reducible or irreducible fractures that occur in patients with poor bone stock and in the vicinity of loose or malpositioned components. These fractures are treated by distal femoral replacement. LEVEL OF EVIDENCE: Therapeutic study, level V (expert opinion). See Guidelines for Authors for a complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗
PubMed2006

Recurrent instability after total hip arthroplasty: beware of subtle component malpositioning.

Most patients exhibiting instability after total hip arthroplasty can be treated nonoperatively. However, instability may become recurrent and require surgical intervention. Abductor insufficiency and component malpositioning constitute two of the most important causes of recurrent instability, although the exact cause may not be identifiable in some patients. There is relative scarcity of reports in the literature regarding the outcome of surgical intervention for recurrent instability; however, it is known that surgical intervention is likely to have a better outcome in patients for whom the cause of recurrent instability can be identified. We hypothesized that component malpositioning, which may be subtle in some cases, is the cause of recurrent instability for many patients. The outcomes of revision arthroplasty in 93 patients who were treated at our institution for recurrent instability were reviewed. Component malpositioning was found to be the major cause of recurrent instability in this successfully treated cohort.

Adult↗
PubMed2006

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↗
PubMed2006

Internet promotion of MIS and CAOS in TKA By Knee Society members.

Minimally invasive surgery (MIS) and computer-assisted orthopaedic surgery (CAOS) options for total knee arthroplasty (TKA) have become increasingly popular. However, few controlled studies document their efficacy and safety. We examined the Internet for Knee Society members' websites to evaluate the level of promotion for these procedures in terms of direct (surgeon endorsed) and indirect (surgeon associated) information. On 92 websites, 22.7% made indirect reference to MIS TKA, while only 10.9% made a direct reference. Of the sites referencing MIS TKA, faster recovery was reported on 90% of indirect sites and 50% of direct sites. Specific risks were discussed on only 35% of indirect sites, and on only 20% of direct sites. CAOS TKA was discussed on 6.5% of indirect sites and on 5.4% of direct sites. Although MIS and CAOS TKA are frequently discussed on the Internet, only a small percentage of KS members directly promote these techniques (10.9% and 5.4%, respectively). Information was often indirectly associated with KS surgeons through institutional websites or hospital affiliations. Information indirectly associated with a surgeon may be mistaken as endorsing the procedure by a prospective patient.

Arthroplasty, Replacement, Knee↗
PubMed2006

Muscle damage during MIS total hip arthroplasty: Smith-Petersen versus posterior approach.

Decreased muscle damage is a reported benefit of minimally invasive surgical (MIS) approaches in total hip arthroplasty (THA). We compared the extent and location of muscle damage during THA using the MIS anterior Smith-Petersen and MIS posterior surgical approaches. THA was performed in six human cadavers (12 hips). One hip was assigned to the Smith-Petersen approach and the contralateral hip to the posterior approach. Muscle damage was graded with a technique of visual inspection to calculate a proportion of surface area damage. Less damage occurred in the gluteus minimus muscles and minimus tendon with the Smith-Petersen approach. A mean of 8% of the minimus muscle was damaged via the Smith-Petersen approach, compared to 18% via the posterior approach. The tensor fascia latae muscle was damaged (mean of 31%), as well as direct head of the rectus femoris (mean 12%) during the Smith-Petersen approach. The piriformis or conjoined tendon was transected in 50% of the anterior approaches to mobilize the femur. The posterior approach involved intentional detachment of the piriformis and conjoined tendon and measurable damage to the abductor muscles and gluteus minimus tendon in each specimen. Clinical outcome studies and gait analysis are necessary to ascertain the functional implications of these findings.

Aged↗
PubMed2006

2006 Otto Aufranc Award Paper: significance of in vivo degradation for polyethylene in total hip arthroplasty.

Our research group developed an implant retrieval program to study in vivo degradation of polyethylene. We now have evidence to support our hypothesis that degradation of radiation-sterilized polyethylene occurs in the body for not only historical gamma air sterilized liners, but also for conventional gamma inert sterilized (ArCom) and annealed highly crosslinked polyethylene (Crossfire) liners as well. Our research has also led to the discovery that the most severe manifestations of in vivo oxidation typically occur in regions of the liner experiencing minimal wear, such as the rim of the component, where the body fluids (containing oxidizing species) have access to the polyethylene. Our data from historical, ArCom, and Crossfire retrievals all point to a similar scenario in which the femoral head limits the in vivo oxidation of polyethylene at the bearing surface. Consequently, provided rim impingement does not occur, and the polyethylene locking mechanisms remain relatively isolated from oxidizing fluid, in vivo oxidation does not seem to be clinically important in the first 10 years of implantation for conventional gamma sterilized polyethylene. We conclude that in vivo degradation should be included among the list of potential long-term failure modes for modular polyethylene components for total hip arthroplasty.

Arthroplasty, Replacement, Hip↗