GUEPAR knee arthroplasty results and late complications.

One hundred eight GUEPAR knee arthroplasties have been studied with a follow-up of one year on 41; 2 years on 22 and 3 years on 45 knees. Overall results were 17% excellent, 44% good, 10% fair and 29% poor. Excellent results were comparatively fewer in rheumatoid arthritis. There was a deterioration in the quality of results of arthroplasty with longer follow-up. The incidence of deep infection was 11%. There was a significant correlation between early wound drainage and deep infection. More than half of the infected knees have not required intervenition as yet. One knee was revised and 3 had attempted arthrodesis with one successful fusion. Two patients died with septicemia. Axle migration occurred in 8 knees and femoral stem breakage in 2 knees. Loosening was found in 27% of the knees with progressive reduction in quality of the arthroplasty. Incomplete cementing predisposed to loosening. Patellar symptoms were present in 28% of the knees. Patellar subluxation and dislocation occurred in 49% of the knees. More than half of these were symptomatic. With normal patellofemoral alignment, pain was more common in the osteoarthritic knee. Use of a patellar implant with GUEPAR knee prostesis should be restricted to severely disabled patients with major fixed deformities. Mechanical failure can be minimized by proper positioning of the implant, correct alignment of the extensor mechanism and adequate cement around the entire stem.     

Patterns of osseointegration and remodeling in femoral revision with bone loss using modular, tapered, fluted, titanium stems

Radiographic signs of osseointegration with the use of fluted, tapered, modular, titanium stems in revision hip arthroplasty with bone loss have not been previously categorized. Serial radiographs of 64 consecutive hips with mean follow-up of 6.2 years were retrospectively reviewed. Bone loss was classified as per Paprosky classification, osseointegration was assessed according to a modified system of Engh et al, and Harris Hip Score was used to document pain and function. Seventy-four percent of the hips had type 3 or 4 bone loss. All stems were radiographically osseointegrated. Early minor subsidence was seen in 6.2% of the hips; definite bony regeneration, 73% of the hips; and stress shielding, 26% of the hips. These osseointegration patterns were different from those described for extensively porous-coated cobalt-chromium stems and had a bearing on the evaluation of fixation of these stems.     

The natural history of anterior knee pain in 2 posterior-stabilized, modular total knee arthroplasty designs

Anterior knee pain (AKP) has been a persistent complaint after total knee arthroplasty; however, the natural course of this complaint has not been fully investigated. This is a 10-year follow-up report of a prospective, randomized study between the Insall-Burstein II (Zimmer, Warsaw, IN) and the Press Fit Condylar Modular (Johnson & Johnson, Raynham, MA) knees. Up to one third of total knee arthroplasties will experience mild to moderate AKP at 1-year follow-up, which will persist in approximately 30% of these previously symptomatic knees at 10-year follow-up. New-onset AKP will develop in approximately 10% of previously asymptomatic knees.     

Defining the Origins of the Iliofemoral, Ischiofemoral, and Pubofemoral Ligaments of the Hip Capsuloligamentous Complex Utilizing Computer Navigation

Purpose  

To use computer navigation software to investigate the specific origins of the hip capsuloligamentous complex.     

In vivo contact pressures in total knee arthroplasty

This study compared the in vivo femoropolyethylene contact pressures generated in fixed-bearing total knee arthroplasty (TKAs) with those in mobile-bearing TKAs. In vivo kinematics obtained from a 2-dimensional to 3-dimensional registration technique and soft tissue locations derived from computed tomographic scans were entered into a 3-dimensional inverse dynamics mathematical model to determine the in vivo bearing contact forces. The contact areas were obtained from the assembly of computer-aided design models of the components. The contact pressure was defined as the ratio of the contact forces to the contact areas. The results indicate that the in vivo contact pressures in each TKA are greater for the medial condyle than for the lateral condyle. The ability of the mobile-bearing TKA to rotate maintains higher femoropolyethylene contact, resulting in lesser contact pressures, as compared with the fixed-bearing TKA.     

Fixation and osteolysis in plasma-sprayed hemispherical cups with hybrid total hip arthroplasty

The optimal surface finish on cementless total hip arthroplasty is still a matter of debate. 145 hips in 130 patients with hybrid total hip arthroplasty using a hemispherical, titanium plasma-sprayed cup were followed for an average of 8.5 years. The average age was 63 years, and the average weight was 165 lb. Three hips were revised for polyethylene wear and synovitis/osteolysis. In all 3 cases, the acetabular component remained well fixed. Radiographically, 5 hips had femoral osteolysis, and 5 sockets had osteolysis in zone 2, with 4 in zone 1. There were no cases of progressive lucent lines, and no acetabular components were revised. Plasma-sprayed acetabular components remain durable up to 12 years. Moreover, in cases with wear particle overload and osteolysis, fixation was maintained at revision surgery.     

Current issues in health policy: a primer for the orthopaedic surgeon

Political, social, and economic forces occupy an increasingly larger role in health care. It is essential that orthopaedic surgeons become familiar with the ever-changing landscape within which they practice. Greater comprehension of the current issues in health policy will enable practitioners to appreciate these issues and understand the importance of the involvement of the AAOS in the political process. Five topics in particular will continue to have a great impact on the practice of orthopaedic surgery: the flawed Medicare payment formula, implementation of a pay-for-performance program, the creation of gainsharing agreements between hospitals and physicians, the medical liability crisis, and the importance of advocacy with the political action committee of the AAOS.     

The incidence of venous thromboembolism after total hip arthroplasty: a specific hypotensive epidural anesthesia protocol.

We retrospectively reviewed all consecutive unilateral primary total hip arthroplasty (THA) procedures performed by 3 attending surgeons on the Arthroplasty Service at our institution from January 1, 1990, to December 31, 1993. All surgery was performed under a specific hypotensive epidural anesthesia protocol. Hypotensive epidural anesthesia at our institution provides a lower level of hypotension (mean arterial pressure of 50-60 mmHg) as compared to hypotensive anesthesia used more generally around the world (mean arterial pressure >70 mmHg). For each patient, hospital and postdischarge office records for a minimum of 3 months after surgery were reviewed for the type of postoperative screening test, the incidence of deep venous thrombosis (DVT), and the incidence of symptomatic pulmonary embolism (PE). Overall, 2,592 primary unilateral THAs were performed with 78.6% (2,037 of 2,592) of patients receiving a venogram. Our protocol for thromboembolic disease prophylaxis in these patients included aspirin postoperatively as well as antithromboembolic disease stockings and early ambulation (24-48 hours postoperatively). The 555 patients who did not receive venography were managed with a different protocol that included warfarin postoperatively as well as antithromboembolic disease stockings and early ambulation. This high-risk group consisted of patients who received warfarin preoperatively (ie, cardiac valve) or patients with a history of DVT who were to receive warfarin postoperatively, regardless of venography result. Overall, DVT was diagnosed in 10.3% (210 of 2,037) of patients who had a venogram. Of these patients who had venography, 2.3% (46 of 2,037) had an isolated proximal DVT; 6.0% (123 of 2,037), a distal DVT; and 2.0% (41 of 2,037), both a proximal and a distal DVT. Of the 87 cases of proximal DVT identified, 60.9% (53 of 87) were femoral DVT; 18.4% (16 of 87), popliteal DVT; and 20.7% (18 of 87), both femoral and popliteal DVT. Of the 164 distal DVT, 68.3% (112 of 164) were major calf DVT and 31.7% (52 of 164) were minor calf DVT. The overall incidence of major venous thrombosis (sum of proximal and major calf thrombi) was 9.8% (199 of 2,037) in patients who had venography. Ventilation-perfusion scanning was used selectively in patients symptomatic for PE. Overall, symptomatic PE was diagnosed by ventilation-perfusion scan in 1.0% (26 of 2,592) of patients, with 0.58% (15 of 2,592) of patients having an in-hospital PE. Of the 15 patients who had an in-hospital PE, 11 patients had a venogram, and only 3 of 11 were positive. Late symptomatic PE was defined from discharge (mean, 7 +/- 2 days) to 3 months after discharge from the hospital and occurred in 0.42% (11 of 2,592) of patients. One of the 11 late symptomatic PEs was fatal. In the overall study, this represents 0.04% (1 of 2,592) fatal PE. Of the 11 patients with a late symptomatic PE, 10 had venograms in the hospital, and all 10 were negative for DVT. Overall, in the patients with a positive venogram, the incidence of symptomatic PE was 1.4% (3 of 210), whereas in the patients with a negative venogram, the incidence of symptomatic PE was 0.44% (8 of 1,827). At our institution, patients who undergo primary THA performed with hypotensive epidural anesthesia, postoperative aspirin, antithromboembolic disease stockings, and early ambulation have a low risk for thromboembolic disease.     

Role of Anatomical Patella Replacement on Anterior Knee Pain

Background

Anterior knee pain (AKP) remains a complex issue affecting patient satisfaction after total knee arthroplasty. Several radiographic parameters have been shown to be causative factors with various designs. The aim of this study is to evaluate the known radiographic parameters of AKP and clinical outcomes (ie, AKP) in the setting of a modern prosthesis with an anatomic patella button.