Long-term performance of oxidized zirconium on conventional and highly cross-linked polyethylene in total hip arthroplasty.

Introduction: Polyethylene wear and subsequent osteolysis remain obstacles to the long-term survivorship of total hip arthroplasty (THA). Highly cross-linked polyethylene (XLPE) with radical quenching represents a massive leap forward with dramatically improved wear rates compared to ultra-high molecular weight polyethylene (UHMWPE). In this study we evaluate the wear of UHMWPE and XLPE coupled with oxidized zirconium (OxZr) femoral heads.

Posterior Soft Tissue Repair After Primary THA is Durable at Mid-term Followup: A Prospective MRI Study.

Background: The enhanced posterior soft tissue repair has reduced the frequency of dislocation after primary THA performed through the posterolateral approach. However, the long-term integrity of the repair is unknown and could influence surgeon choice regarding surgical technique and THA approach.

Questions/purposes: We asked: (1) What is the durability of the enhanced posterior soft tissue repair at a minimum of 49 months using MRI to evaluate soft tissue to bone integrity? (2) How does the appearance of the posterior soft tissues change during this time? (3) Are there patient characteristics associated with the long-term imaging appearance of the posterior repair?

Methods: All patients without a contraindication for MRI who were undergoing unilateral primary uncemented THA through a posterior approach between February and May 2005 were eligible for inclusion.

Ceramic liner fractures presenting as squeaking after primary total hip arthroplasty.

Background: Squeaking after ceramic-on-ceramic total hip arthroplasty is a relatively uncommon phenomenon. It usually does not require treatment in the absence of pain, mechanical symptoms, and/or relentless squeaking. The purpose of this investigation was to report on four patients who presented with hip pain and squeaking due to fractured ceramic liners after ceramic-on-ceramic total hip arthroplasty.

Failure mechanisms and closed reduction of a constrained tripolar acetabular liner.

Unlike traditional bipolar constrained liners, the Osteonics Omnifit constrained acetabular insert is a tripolar device, consisting of an inner bipolar bearing articulating within an outer, true liner. Every reported failure of the Omnifit tripolar implant has been by failure at the shell-bone interface (Type I failure), failure at the shell-liner interface (Type II failure), or failure of the locking mechanism resulting in dislocation of the bipolar-liner interface (Type III failure). In this report we present two cases of failure of the Omnifit tripolar at the bipolar-femoral head interface.

MRI shows biologic restoration of posterior soft tissue repairs after THA.

Although posterior capsule repair reduces the incidence of dislocation after THA, radiographic imaging studies suggest a high failure rate of the repair. Using MRI, we prospectively followed patients to evaluate the integrity of the posterior soft tissue repair after primary THA. Thirty-six patients (21 men, 15 women) underwent arthroplasty using a standard posterior approach.

Randomized trials to modify patients' preoperative expectations of hip and knee arthroplasties.

Unlabelled: Patients have multiple expectations of THA and TKA. We asked whether preoperative educational classes addressing recovery during the first year could modify patients' expectations of their 12-month postoperative recovery. Participants were enrolled consecutively in two randomized, controlled trials, one for THA (177 patients) and one for TKA (143 patients).

Constrained condylar knee without stem extensions for difficult primary total knee arthroplasty.

Two hundred forty-eight constrained condylar total knee arthroplasties consecutively implanted without the use of diaphyseal stem extensions were studied in 180 patients. Preoperative deformity was severe (82% Ahlbäck grade 4-5). One hundred ninety-two knees (148 patients) were reviewed at mean 47-month follow-up (range: 24-72 months).

Varus rotational osteotomies for adults with hip dysplasia: a 20-year followup.

Untreated hip dysplasia predisposes young adults to early arthritis. Varus rotational osteotomies are considered one option to delay or eliminate total hip arthroplasty. We update a report from 1991 by retrospectively reviewing 40 of 48 patients (83.

Analysis of cement mantles in collared versus collarless femoral components.

The purpose of this study was to compare the cement mantles of 100 consecutive collared cemented stems with those of 100 consecutive collarless cemented stems of similar design. All stems were implanted by the same surgeon. Two independent examiners retrospectively reviewed the results.

Integrity of repaired posterior structures after THA.

Various studies have questioned the benefit of repairing the posterior structures after total hip arthroplasty because their integrity can appear disrupted at followup. However, these studies did not directly examine the posterior structures. We hypothesized that repaired posterior structures remain intact after total hip arthroplasty, and that their integrity could be evaluated by ultrasonography.

Prevalence of infection in bilateral total hip arthroplasty: a comparison of single-stage 565 bilateral procedures performed with 1 or 2 sets of instruments.

Single-stage bilateral total hip arthroplasty can be performed with a completely new sterile setup for the second side or with the same instruments for both sides. The latter could theoretically lead to a higher prevalence of infection in the second side. We retrospectively determined the prevalence of deep infection during the first postoperative year in 271 consecutive patients operated on with different sterile setups (group 1) and 289 patients operated on with the same setup (group 2).

Primary constrained condylar knee arthroplasty without stem extensions for the valgus knee.

Unlabelled: Avoiding stem extensions in total knee arthroplasties may decrease operative time, prosthetic cost, and canal invasion at surgery. A constrained condylar knee implant without stem extensions also likely will be easier to revise and will eliminate the risk of end of stem pain. Our hypothesis was that a constrained condylar knee implant for primary severely deformed knees would show excellent midterm results with a low rate of aseptic loosening, even without diaphyseal-engaging stems.

Late fatigue fracture of a modern cemented [corrected] cobalt chrome stem for total hip arthroplasty: a report of 10 cases.

We report 10 fatigue fractures of a modern, cemented, cobalt chromium alloy stem (Osteonics Omnifit) for total hip arthroplasty occurring between 1995 and 2004. The primary total hip arthroplasties had been performed between 1989 and 1996. The average age at the time of surgery was 54 years (range, 34-70 years), and the average body mass index was 29 (range, 20-38).

The role of constrained liners in total hip arthroplasty.

Recurrent instability after total hip replacement is a complex problem with extensive literature detailing multiple etiologies and solutions. It has been shown that the success of surgical treatment depends on the identification of the cause. Unfortunately, in certain situations, there may not be an optimal solution for dealing with the cause, or the cause may remain unidentified.

The use of a constrained acetabular component for recurrent dislocation.

The poor results of surgical treatment of chronic instability after total hip arthroplasty (THA) led to the development of a constrained acetabular component. In this study, 87 constrained THAs implanted for recurrent instability were reviewed retrospectively. Eighty-five hips were available for follow-up evaluation, with an average follow-up period of 58 months.

Complications in primary total hip arthroplasty: avoidance and management of dislocations.

Dislocation in primary total hip arthroplasty is common and problematic and is attributable to several factors, including previous hip surgery, neuromuscular disorders, cerebral dysfunction, psychosis, alcoholism, and female gender. Factors under the control of the surgeon include component orientation and restoration of soft-tissue tension. Prosthetic factors lowering the risk of dislocation include increasing the size of the prosthetic femoral head, keeping femoral neck circumference to a minimum, and optimizing the geometry of the acetabular component.

Single-stage bilateral total hip arthroplasty.

The number of single-stage bilateral total hip arthroplasties done each year is increasing. The risk of postoperative complications in medically stable patients is acceptable; complications are approximately 1.3 times more frequent than with unilateral total hip arthroplasty.