William Hopkinson

The Porous-Coated Anatomic Total Hip Prosthesis, Inserted without Cement. A Prospective Study with a Minimum Ten Years of Follow-up*

One hundred consecutive primary total hip arthroplasties performed with use of a porous-coated anatomic total hip prosthesis, fixed without cement, in ninety-one patients were followed prospectively for a minimum of ten years. At the time of the most recent follow-up, twenty patients (twenty-three hips) had died and seventy-one patients (seventy-seven hips) were living. The average age of the living patients was sixty-six years (range, thirty-two to ninety-two years), and their average Harris hip score was 84 points (range, 33 to 100 points). Twelve percent (nine) of the seventy-seven hips were found to be associated with pain in the thigh when the patients were specifically questioned by the examiner. Eleven hips were revised during the follow-up period. Only the acetabular component was revised in six hips, only the femoral component was revised in one hip, and both the femoral and the acetabular components were revised in four hips. Of the ten acetabular revisions, one was performed because of acute dissociation of the component and eight, because of a combination of polyethylene wear, osteolysis, and loosening; the tenth acetabular revision consisted of exchange of the liner and curettage and bone-grafting of the osteolytic area. Of the five femoral revisions, two were performed because of loosening and three, because of extensive osteolysis of the proximal aspect of the femur. Including the revised components, twelve acetabular components and five femoral components had radiographic evidence of aseptic loosening. Acetabular osteolysis occurred in seventeen hips. Femoral osteolysis occurred in thirty-nine hips: in the proximal aspect of thirty-one hips, in the distal aspect of four, and in both the proximal and the distal aspect of four. The durability of the femoral fixation documented in this study is especially encouraging in view of the fact that this was our initial experience with devices fixed without cement and that a so-called first-generation femoral component was used. However, the study also demonstrated that not all acetabular components fixed without cement function well over the long term and that specific design considerations (adequate initial fixation, congruency between the liner and the shell, an optimum shell-liner capturing mechanism, and a smaller femoral head) are warranted.

Preoperative risks and outcomes of hip and knee arthroplasty in the veterans health administration

The relationship between patient characteristics and outcomes of total joint arthroplasty (TJA) was examined in a population of veterans treated in VA hospitals. Outcomes included 30-day mortality and morbidity, postoperative length of stay, and readmission caused by surgical complications. A larger proportion of women then men were functionally impaired before surgery in both the hip (22% vs. 14%) and knee samples (14% vs. 7%; all P<.01). Rates of adverse outcomes in this population were very low. Preoperative comorbid conditions, abnormal laboratory values, and being nonwhite were related to poor outcomes of TJA. Gender was a significant independent predictor of morbidity and length of stay for total knee arthroplasty.

Fixed- vs mobile-bearing total knee arthroplasty: does it make a difference?--a prospective randomized study.

The purpose of this prospective, randomized study was to compare the early clinical and functional results of primary total knee arthroplasty using a fixed-bearing (FB) and a rotating-platform (RP) prosthesis. Outcomes including range of motion (ROM), Knee Society Score, Western Ontario MacMaster (WOMAC), and Short Form-36 (SF-36) were measured preoperatively and at 6 weeks, 3 months, 6 months, 1 year, and 2 years. Radiographic analysis was performed. There were 72 FB and 68 RP knees. The RP group had a greater ROM at 6 weeks and 1 year. This difference was not statistically significant at 2 years. There were no differences in the ROM at any other period. There were no significant differences in Knee Society Score, Short Form-36, or Western Ontario MacMaster scores at any period. No clinically significant differences were noted in the radiographic analysis. The use of a FB or RP design did not affect the early functional outcomes after total knee arthroplasty.

Effect of Intraoperative Blood Loss on the Serum Level of Cefazolin in Patients Managed with Total Hip Arthroplasty. A Prospective, Controlled Study*

The effect of intraoperative blood loss on serum levels of cefazolin in patients being managed with total hip arthroplasty was studied. Eighteen patients, thirteen men and five women, with a mean age of sixty-five years (range, forty to eighty-five years) were enrolled in the study. Fifteen had a primary total hip arthroplasty and three, a revision. Each patient served as his or her own control. Baseline clearance of cefazolin was determined at a minimum of forty-eight hours before the operation. Each patient received one gram of cefazolin intravenously. Serial serum concentrations were determined from specimens drawn at zero, five, ten, twenty, thirty, sixty, 120, 240, and 300 minutes after administration. Fifteen minutes before the skin incision was made, each patient again received one gram of cefazolin intravenously. Serum samples were collected at the same time-intervals, and the serum levels of cefazolin were determined with use of capillary electrophoresis. Data regarding intraoperative blood loss as well as replacement of fluid and blood were recorded. The administration of the antibiotic, retrieval of the serum samples, and estimation of the blood loss were performed by the same person in the same manner for all patients. The preoperative and intraoperative creatinine clearances (mean and standard deviation), estimated with use of the formula of Cockcroft and Gault, were 62.06 ± 21.28 and 74.02 ± 24.75 milliliters per minute, respectively. The amount of intraoperative blood loss averaged 1137 ± 436 milliliters (range, 675 to 2437 milliliters). The preoperative and intraoperative cefazolin clearances averaged 0.49 ± 0.21 and 0.52 ± 0.30 milliliter per minute per kilogram, respectively. During joint replacement, the commonly accepted interval between doses of cefazolin is four hours. In the present study, the serum level of cefazolin at four hours was forty-five micrograms per milliliter. This corresponds to an osseous concentration that well exceeds the minimum inhibitory concentration for Staphylococcus aureus, which is 0.5 microgram per milliliter. This study suggests that, with blood losses of less than 2000 milliliters, it is not necessary to administer cefazolin at intraoperative intervals of less than four hours in order to maintain a concentration of antibiotics that is higher than the minimum inhibitory concentration for the most common infecting organisms.

The Relationship Between Knee Arthroplasty and Foot Loading

Surgeons have questioned whether foot deformity applies abnormal loading on a knee implant. A total of 24 patients with mild knee deformity underwent a static recording of foot loading prior to and at 3 months following knee replacement. Of these patients, 13 had a preoperative varus deformity. The recorded postoperative to preoperative loading in all 6 geographic sites was decreased by an average of 10%. The largest changes were observed in the hallux and lesser toe masks, whereas the postoperative to preoperative foot pressure ratio in the metatarsal head (lateral and medial), heel, and midfoot masks was 0.94. This preliminary investigation reveals a minimal change in geographic foot loading following total knee arthroplasty in patients with mild knee deformity. Levels of Evidence: Therapeutic, Level IV

Inflammatory Biomarker Profiling in Elderly Patients With Acute Hip Fracture Treated With Heparins

Hip fracture is common in the elderly patients with associated high risk of venous thromboembolic complications. Pathogenic activation results in the generation of various surrogate markers in plasma. This study is designed to identify unique biomarkers in elderly patients with hip fracture using protein chip array enzyme-linked immunosorbent assay (ELISA) methods. Plasma from a randomized hip fracture study (PK-532; n = 341) treated with either enoxaparin (40 mg once daily) or unfractionated heparin (UFH; 5000 IU twice daily) were collected prior to and at 1, 3, 5, and 7 days. A total of 52 samples were analyzed using proteomic surface-enhanced laser desorption/ ionization-time of flight (SELDI-TOF) mass spectrometry to identify unique biomarkers in the molecular weight range of 0 to 150 kd. Twenty-nine healthy volunteer’s and pooled plasma from total hip replacement/total knee replacement patients with a unique biomarker at 11.9 kd were used as quality controls. In the 29 healthy individuals, the biomarker profile did not reveal the presence of any unique peak in comparison to the reference normal human plasma (NHP). Plasma obtained prior to surgery exhibits unique biomarkers in 4 of 52 (7.6%) of the samples. On day 1 postoperatively, 41 of 51 (80.3%) showed a distinct peak at 11.9 kd. On day 3, 43 of 49 (87.8%) patients showed the presence of this biomarker most often at its strongest intensity. In all, 22 of 44 (50%) showed this biomarker on day 5 and 4 of 23 (17.9%) on day 7. C-reactive protein (CRP), tumor necrosis factor α (TNF-α), and serum amyloid A were also increased after surgery. Tissue factor pathway inhibitor (TFPI) antigen levels were increased due to the treatment modalities.

Dysregulation of Tissue Factor, Thrombin-Activatable Fibrinolysis Inhibitor, and Fibrinogen in Patients Undergoing Total Joint Arthroplasty

Total joint arthroplasty (TJA) of the hip or knee (THA, TKA) has become an increasingly common procedure. While TJA is a successful treatment for individuals experiencing degenerative joint diseases, it is well known that one of the most common perioperative complications of TJA is deep venous thrombosis (DVT). To profile tissue factor (TF), microparticle-tissue factor (MP-TF), thrombin-activatable fibrinolysis inhibitor (TAFI), and fibrinogen levels in patients undergoing TJA to determine potential preexisting Hemostatic dysregulation. De-identified blood samples were obtained from patients undergoing TJA 1 day pre- and 1 day postprocedure. Plasma samples were analyzed using enzyme-linked immunosorbent assay kits for fibrinogen, TAFI, TF, and MP-TF; fibrinogen levels were also assessed using a clot-based activity assay. In comparison with healthy controls, there were significant increases of fibrinogen and MP-TF levels, while there were significant decreases in TF and TAFI levels in the preoperative and postoperative patients. Comparing the pre versus postoperative patients, no significant differences were found; interestingly, however, surgical intervention exacerbated the changes found in the preoperative samples compared to the controls. The results of this study confirm that patients undergoing TJA have preexisting alterations in the fibrinolytic system. Surgical intervention tended to exacerbate these changes. The alterations observed in this study may provide insight as to why TJA is associated with higher rates of DVT and thromboembolism.

Fibrinolytic Dysregulation in Total Joint Arthroplasty Patients: Potential Clinical Implications.

Background: The alterations of the fibrinolytic components in osteoarthritic joint disease and their postsurgical modulation are not clearly understood. Preexisting hemostatic dysfunction may lead to both thrombotic and bleeding events in these patients. Aim: To profile fibrinolytic parameters in patients undergoing total joint arthroplasty prior to and on postoperative day 1. Methods: A total of 98 total joint arthroplasty patients were included in this study. Blood samples were drawn preoperatively and on postoperative day 1 status posttotal knee or total hip arthroplasty surgery. d-Dimer, plasminogen activator inhibitor 1 (PAI-1), and tissue plasminogen activator (tPA) were measured using commercially available enzyme-linked immunosorbent assay kits. Antiplasmin activity was measured by using a functional method. Results: Preoperative PAI-1, d-dimer, and tPA levels were significantly higher in arthroplasty patients compared to healthy controls. Preoperative antiplasmin level was lower than controls. Postoperative levels of PAI-1 and d-dimer were increased compared to preoperative values. Postoperative antiplasmin values were lower than preoperative levels. Changes in tPA was not significant. There was no correlation between preoperative PAI-1 and d-dimer levels. Pre- and postoperative percentage changes in each individual were calculated for PAI-1, d-dimer, tPA, and antiplasmin. There was a positive correlation between d-dimer and PAI-1. Negative correlations between antiplasmin and d-dimer and between antiplasmin and PAI-1 were noted. Conclusion: These results confirm the perturbation in the fibrinolytic system of patients undergoing total joint arthroplasty surgery. Surgical intervention may also enhance the observed changes. The alterations in the fibrinolytic system may lead to the observed hemostatic complications such as bleeding, hematoma formation, or potential need for blood transfusion.

Levels of Matrix Metalloproteinases in Arthroplasty Patients and Their Correlation With Inflammatory and Thrombotic Activation Processes

An imbalance of matrix metalloproteinases (MMPs) and their inhibitors is thought to play a major role in the pathophysiology of joint diseases. The aim of this study is to provide additional insights into the relevance of MMP levels in arthroplasty patients in relation to inflammation and thrombosis. Deidentified plasma samples from 100 patients undergoing total hip arthroplasty or total knee arthroplasty were collected preoperatively, on postoperative day 1, and on postoperative day 3. Tissue inhibitor of MMP 4, tumor necrosis factor α (TNF-α), pro-MMP1, MMP3, MMP9, MMP13, and d-dimer were measured using enzyme-linked immunosorbent assay kits. A biochip array was used to profile interleukin (IL) 2, IL-4, IL-6, IL-8, IL-10, vascular endothelial growth factor (VEGF), interferon gamma, TNF-α, IL-1α, IL-1β, monocyte chemoattractant protein 1, and endothelial growth factor (EGF) levels. The levels of MMP1, MMP9, MMP13, and TNF-α were elevated preoperatively in arthroplasty patients when compared to healthy individuals. The concentrations of MMP1 and MMP9 increased slightly in postsurgical samples. d-Dimer levels were elevated preoperatively, increased postoperatively, and started decreasing on postoperative day 3. Significant correlations between MMP9 with TNF-α, IL-6, IL-8, VEGF, and EGF were identified. Elevated preoperative MMP1, MMP9, and MMP13 concentrations suggest that they may play a role in the pathogenesis of arthritis. There is also evidence of increased coagulation activity and possible upregulation of several MMPs postsurgically. Correlation analysis indicates that MMP9 levels may potentially be related to inflammation and thrombosis in arthroplasty patients.

Hip Arthroplasty or Medical Management: A Challenging Treatment Decision for Younger Patients

The two main treatment options for total hip arthroplasty (THA), medical management and surgical intervention, have advantages and disadvantages, creating a challenging decision. Treatment decisions are further complicated in a younger population (≤50) as the potential need for revision surgery is probable. We examined the relationship of selected variables to the decision-making process for younger patients with symptomatic OA. Thirty-five participants chose surgical intervention and 36 selected medical management for their current treatment. Pain, activity restrictions, and total WOMAC scores were statistically significant (P < .05) for patients selecting surgical intervention. No difference in quality of life was shown between groups. Pain was the only predictor variable identified, however, activity restrictions were also influential variables as these were highly correlated with pain.