Thomas B. Pace

Intraoperative Platelet Rich Plasma Usage in Total Knee Arthroplasty: Does It Help?

Autologous platelet rich plasma preparations, commonly referred to as platelet gel, have been reported to have benefits when used in total knee replacement of less blood loss and better motion, with few reported complications. This retrospective review of 268 consecutive primary total knee arthroplasty cases compares postsurgical range of motion at 2, 8, and 12 weeks, knee manipulation rates, change in hemoglobin, and complications between one group receiving a platelet gel preparation (135 cases), and an equivalent group receiving no platelet gel preparation (133 control cases). No difference was found between groups in manipulation rates, knee range of motion, or changes in hemoglobin (P > 0.05). The use of platelet gel in this study did not have a significant effect on hemoglobin at 72 hours postoperatively, knee range of motion, or manipulation rates up to 3 months post-op in this patient cohort.

Comparison of conventional polyethylene wear and signs of cup failure in two similar total hip designs.

Multiple factors have been identified as contributing to polyethylene wear and debris generation of the acetabular lining. Polyethylene wear is the primary limiting factor in the functional behavior and consequent longevity of a total hip arthroplasty (THA). This retrospective study reviewed the clinical and radiographic data of 77 consecutive THAs comparing in vivo polyethylene wear of two similar acetabular cup liners. Minimum follow-up was 7 years (range 7–15). The incidence of measurable wear in a group of machined liners sterilized with ethylene oxide and composed of GUR 1050 stock resin was significantly higher (61%) than the compression-molded, GUR 1020, O2-free gamma irradiation sterilized group (24%) (P = 0.0004). Clinically, at a 9-year average followup, both groups had comparable HHS scores and incidence of thigh or groin pain, though the machined group had an increased incidence of osteolysis and annual linear wear rate.

Metal-on-Metal Hip Retrieval Analysis: A Case Report

This is a case report involving a single case with severe bone and soft tissue destruction in a young male patient with a 10-year-metal on-metal total hip arthroplasty. Following complete aseptic erosion of the affected hip greater trochanter and abductor muscles, the hip was revised for recurrent instability. Histological examination of the patients periprosthetic tissues, serological studies, and review of recent medical reports of similar cases were used to support an explanation of the destructive process and better contribute to our understanding of human reaction to metal debris in some patients following metal-on-metal hip arthroplasty.

Short-term results of novel constrained total hip arthroplasty

Constrained acetabular components have only been recommended as a salvage option for the persistently unstable total hip arthroplasty (THA), due to limited range of motion and less than satisfactory component failure rates. This is a retrospective review of 137 patients with 154 consecutive primary constrained THAs performed between November 2003 and August 2007. We reviewed serial radiographs, postoperative complications, groin/thigh pain, and compared preoperative and postoperative Harris Hip Scores. With a mean follow-up of 6 years, there was 1.9% dislocation rate, 0% component failure rate, and 2.6% infection rate. Seven patients reported continued groin pain, and three had continued thigh pain. One patient showed radiographic evidence of 1 mm polyethylene wear. Radiographic review showed no evidence of osteolysis or stem subsidence. Harris Hip Scores improved from a mean of 68.8 (range 58-87) preoperatively to 98.9 (range 65-100) at final clinical assessment. This constrained acetabular prosthesis had a dislocation rate of less than 2%, with 0% component failure rate at a minimum of 2 years of follow-up suggesting this prosthesis may be a viable alternative for patients at risk for instability or those known to have recurrent instability.

Clinical Outcomes of Tibial Components with Modular Stems Used in Primary TKA

Due to the known potential for fretting and corrosion at modular junctions in orthopaedic implants, this retrospective study evaluated radiographic and clinical outcomes of 85 primary TKA patients implanted with modular stemmed tibial components and followed up for an average of 82 months. There was low incidence of tibial radiolucent lines, excellent functional outcomes, and no complications associated with stem modularity. The findings were comparable to the historical control study involving 107 TKA with a nonmodular tibial stem design. When using surface cemented tibial components combined with a constrained polyethylene bearing, modular stems appear to be a viable option for primary TKA when adequate fixation and rotational stability are maintained.

Knee Joint Loading Patterns During Activities of Daily Living in TKR Patients

The kinetics and kinematics of the knee joint during a variety of activities of daily living were studied in a group of total knee replacement (TKR) patients. The parameters examined were those needed to program a force-controlled knee simulator (axial and anterior-posterior (AP) forces, internal-external (IE) moment, and flexion angle). These parameters were calculated for walking, fast walking, stand-to-sit, sit-to-stand, bending, stair ascent and stair descent using body-fixed inertial sensors, a force platform, and estimates of muscles forces. Peak values for loading patterns were not significantly different from those for an age-matched control group. Axial forces were lower in comparison to published results for normal and TKR populations, due to slower cadences and conservative estimates of muscle forces. Peak posterior forces and IE moments were higher than published results. These patterns were combined to form a spectrum loading pattern, with the activities occurring in approximately the same ratios of relative frequency as reported in the literature. The spectrum pattern can be used to program a force-controlled knee simulator in order to apply more relevant loading patterns to knee implants.Copyright

Clinical outcomes assessment of three similar hip arthroplasty bearing surfaces

This report examines the clinical performance of three very similar total hip arthroplasty designs with distinctly different bearing surfaces used over the course 10-17 years. Clinical outcomes assessments for each group are compared in the context of varying implant related costs related to the latest technology at the time of surgery. Eighty-one surgeries were studied and differ by bearing surface. In this study, 36 hips are ceramic on polyethylene, 27 are metal on polyethylene and 18 are metal on metal. All polyethylene components are nonhighly cross-linked. The ceramic on polyethylene group has younger patients, on average, and higher percentage of patients with significant polyethylene wear. These groups have an average follow-up time of 8.6 years when assessing functional hip scores, thigh pain, groin pain, revision surgeries and radiographic osteolysis. The implant purchasing cost at the time of surgery was assessed to determine if a correlation exists between outcomes and the more technologically advanced implants use at the time of surgery. Based on midterm clinical outcome assessment, no correlation between initial hospital cost and clinical outcomes of one bearing surface over another can be found.

Clinical and Radiographic Evaluation of a Commercially Pure Cancellous-Structured Titanium Press Fit Total Hip Prosthetic Stem: Ten-Year Followup of the “Natural Hip” Femoral Stem

This study evaluates the outcomes of 92 hip arthroplasties using a press fit, tapered, split tip, proximally porous ingrowth (CSTi) femoral stem (Zimmer Natural Hip) in consecutive hip arthroplasty patients followed for an average of ten years postoperatively (range 5–16 years). Patients were functionally and radiographically evaluated using Harris Hip Scores and plain radiographs assessing postarthroplasty groin or thigh pain and radiographic signs of stem subsidence, proximal femoral fixation, stress shielding, and related calcar resorption. At followup of 5–10 years, the incidence of groin pain and thigh pain was 9.1% and 3.6%, respectively. This incidence improved over time. Beyond 10 years of followup, groin pain was 2.7% and thigh pain zero. In 89% of cases, there was solid contact between the calcar and the undersurface of the stem collar. Five cases were revised for instability (5.4%). The Harris Hip Scores and the incidence of thigh or groin pain were very favorable compared to other reported press fit total hip arthroplasty stems and not significantly different across a broad age range. There were no cases of stem loosening of failure of bony ingrowth into the stem.

Comparative Outcomes Assessment: Hip Hemiarthroplasty as an Alternative to THA in Patients with Surgically Pristine Acetabulum—Is There Still a Role?

This is a retrospective review of 243 hip arthroplasties treated with either hemiarthroplasty (61 surgeries-Group 1) or total hip arthroplasty (182 surgeries-Group 2). The mid- to long-term results of relatively similar, predominately young patient cohorts were assessed annually via radiographs and the Harris Hip Scores for pain and clinical function. Groin pain persisted in 16.4% of Group 1 and 5.5% of Group 2 (P = 0.0159). Thigh pain persisted in 11.5% of Group 1 and 2.2% of Group 2 (P = 0.0078). Complications in Group 1 were 4/61 including 2 revisions with an overall survival rate of 96.7% versus Group 2 complication rate of 29/182 with 15 revisions and an overall survival rate of 91.8%. There were no cases of acetabular protrusio in Group 1, but 2 cases (1%) in Group 2 had cup loosening or osteolysis. Two cases were revised in Group 1 (3.2%). Both were undersized femoral stems. The fifteen revisions (8.2%) in Group 2 included loose stem (1), instability (8), infections (3), cup loosening (2), and accelerated polyethylene wear (1). Hemiarthroplasty has a higher incidence of thigh and groin pain but fewer complications compared with total hip arthroplasty.

Clinical and Radiographic Comparison of Oxidized Zirconium and Cobalt Chrome Femoral Components of a Single Design Primary Total Knee Arthroplasty: Is the Cost Difference Justified Based on Patient Outcomes?

A review of 120 consecutive total knee arthroplasty patient records was made comparing oxidized zirconium with traditional cobalt chrome alloy femoral components and assessing the clinical and radiographic outcomes of each. The direct hospital implant cost for each of these implant systems was obtained and assessed in the context of any difference in patient Knee Society Scores, knee flexion, pain, probability of metal allergy, and radiographic signs of pending implant failures. At an average of 5.6-year followup (1–11-year range in both groups), the data showed no clinical or radiological variance between the two groups, while the hospital direct implant cost with the oxidized zirconium femoral component was