Terence J. Gioe

Predictors of wound infection in hip and knee joint replacement: results from a 20 year surveillance program

Background. Deep wound infection (DWI) in total knee (TKA) and total hip (THA) arthroplasty has been shown to highly correlate with superficial surgical site infection (SSSI). Although several studies have reported hospital factors that predispose to SSSI, patient factors have not been clearly elucidated.

Analysis of unicompartmental knee arthroplasty in a community-based implant registry.

Radiation cross-linking increases the wear resistance of polyethylene used in total hip replacement. Radiation also generates residual free radicals, which are detrimental to long-term properties of polyethylene. Two approaches are used to stabilize the residual free radicals and terminally sterilize the components. One is postirradiation annealing with gas sterilization and the other is postirradiation melting with gamma sterilization in nitrogen. The hypothesis of the current study is that postirradiation annealing followed by gamma sterilization in nitrogen will result in more free radicals in polyethylene than gamma sterilization either in air or in nitrogen alone. To test this hypothesis, concentration of residual free radicals was quantified in polyethylene that was annealed and gamma sterilized in nitrogen and control polyethylenes gamma sterilized in air versus in nitrogen. Three crosslinked polyethylenes that were melted and gas sterilized also were included in the study. The effects of residual free radicals were studied by accelerated aging. Oxidation levels and weight loss in bidirectional pin-on-disk tests were determined before and after aging. Polyethylene that was subjected to postirradiation annealing and gamma sterilization resulted in 58% more residual free radicals than control polyethylenes. Weight loss of the annealed polyethylene increased by 16-fold on accelerated aging and had three times higher oxidation levels than that measured in control polyethylenes after aging. In contrast, polyethylenes that were stabilized with postirradiation melting and terminally gas sterilized showed no detectable residual free radicals. Accelerated aging did not affect the weight loss and oxidation levels of melted polyethylenes.

Why are total knee replacements revised?: analysis of early revision in a community knee implant registry.

Since 1991, 5760 knee arthroplasty procedures done by 53 surgeons have been registered in a community joint implant registry and were reviewed regarding initial revision done within the healthcare system. The 168 revisions done represented 2.9% of the knee arthroplasties between September 1991 and December 2002. Survival was defined as the absence of revision surgery. Death was considered a censored event. Cumulative survival rates for the different total knee arthroplasty configurations were: cemented total knee arthroplasty with all-polyethylene tibia, 99.2%; cemented total knee arthroplasty with metal-backed tibia, 96.3%; hybrid total knee arthroplasty, 89.3%; and unicondylar knee arthroplasty, 87.2%. Cemented total knee arthroplasty with metal-backed tibia had better survival than hybrid total knee arthroplasty, ingrowth total knee arthroplasty, and unicondylar knee arthroplasty. Cemented total knee arthroplasty with a metal-backed tibia did not have better survival than cemented total knee arthroplasty with an all-polyethylene tibia. Gender was not related to survival. Age was related to survival, with older patients’ knees surviving longer. Aseptic loosening or wear was the cause of revision in 40.8% of patients having total knee arthroplasty and 46.6% of patients having unicondylar knee arthroplasty, whereas progression of arthritis necessitated unicondylar knee revision in 51.2% of patients having that procedure. This study presents further evidence of the value of and ongoing need for total joint registries. Cemented total knee arthroplasty with all-polyethylene tibia and with metal-backed tibia showed more than 95% 10-year cumulative survival. Hybrid total knee arthroplasty, ingrowth total knee arthroplasty, and unicondylar knee arthroplasties did not show such good results.

Knee arthroplasty in the young patient: survival in a community registry.

Operative options for the younger patient with an arthritic knee remain controversial. We prospectively followed 1047 patients 55 years old or younger who underwent knee arthroplasty in a community joint registry over a 14-year period. Patients were implanted with 1047 joints of three predominant designs by 48 surgeons in four hospitals associated with a community joint registry. The mean age for this cohort was 49.8 years, and 62.8% (657/1047) of the patients were female. There were a total of 73 revisions performed, 5.6% (37/653) in women and 9.2% (36/394) in men. Cemented TKAs performed best, with a cumulative revision rate of 15.5%, compared to 32.3% in unicompartmental knee arthroplasty (UKA) patients and 34.1% in cementless designs. Men had a higher cumulative revision rate than women, 31.9% compared to 20.6%. Adjusting for implant type and gender, there was no difference in cumulative revision rate based on diagnosis (OA versus other) or age group (≤40, 41-45, 46-50, 51-55 years) or between cruciate-retaining and -substituting designs. Eighty five percent of cemented TKA implants survived at 14 years in the population under 55 years of age in this community registry. Cementless designs and UKA increased revision risk independently.Level of Evidence: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Mobile and fixed-bearing (all-polyethylene tibial component) total knee arthroplasty designs. A prospective randomized trial.

BACKGROUND Proponents of mobile-bearing total knee arthroplasty believe that it has potential advantages over a fixed-bearing design in terms of diminished wear and improved motion and/or function, but these advantages have not been demonstrated in a randomized clinical comparison to our knowledge. We conducted a patient-blinded, prospective, randomized clinical trial to compare mobile-bearing and fixed-bearing cruciate-substituting total knee arthroplasties of the same design. METHODS Patients between the ages of sixty and eighty-five years were prospectively randomized to receive a cruciate-substituting rotating-platform design or a fixed-bearing design with an all-polyethylene tibial component. There were no significant differences in the demographic characteristics (mean age, 72.2 years; mean American Society of Anesthesiologists score, 2.7; mean body mass index, 31.8 kg/m(2)) or preoperative clinical or radiographic measures between the groups. Routine clinical and radiographic follow-up measures included the Knee Society score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Short Form-36 (SF-36) outcome measures. RESULTS The results of 312 arthroplasties (136 with an all-polyethylene tibial component and 176 rotating-platform designs) in 273 patients were analyzed at a minimum of two years (mean, forty-two months) postoperatively. Although there was significant improvement in both groups, there was no significant difference between the groups with regard to the mean postoperative range of motion (110.9 degrees and 109.1 degrees, respectively; p = 0.21), the mean KSS clinical score (90.4 and 88.2 points; p = 0.168), or the mean KSS pain score (44.9 and 43.1 points; p = 0.108) at this follow-up point. There were ten revisions: seven because of infection, one because of patellar fracture, one because of instability, and one because of aseptic loosening. CONCLUSIONS The two designs functioned equivalently at the time of early follow-up in this low-to-moderate-demand patient group. The rotating-platform design had no significant clinical advantage over the design with the all-polyethylene tibial component.

The effect of indomethacin on para-articular ectopic ossification following total hip arthroplasty.

Three patients exhibiting Grade III para-articular ectopic ossification following bilateral hip arthroplasty were successfully treated by excision of the bone and small-dose, short-term indomethacin therapy. Based on these results, a preliminary study was performed to determine the effect of indomethacin used prophylactically in patients who were predisposed to ectopic ossification and were undergoing total hip arthroplasty. Of a retrospective control group of 24 hips with extensive bilateral osteoarthritis, 63% were found to develop ectopic ossification following arthroplasty compared to 17% of a similar group treated with indomethacin (p less than 0.001). The ectopic ossification in the indomethacin-treated group possibly was of lesser severity (Grade I) than that encountered in the control group.

All-polyethylene and metal-backed tibias have similar outcomes at 10 years: A randomized level II evidence study

The advantages of a monoblock design and lower cost have generated renewed interest in all-polyethylene tibial components for total knee arthroplasty (TKA). We hypothesized an all-polyethylene design would function equivalently to a metal-backed modular design at lower cost and at long-term followup. We report the 8- to 12-year followup of our earlier reported prospective randomized comparison of a modern congruent all-polyethylene tibial component with a modular metal-backed tibial component of the same design. The mean age of the patients was 69 years and 92% were diagnosed with osteoarthritis. Of 290 patients (316 total knee arthroplasties) enrolled, 120 patients died, 22 had revision surgery, and one was lost to followup. We followed the remaining 147 patients (167 TKAs: 97 all-polyethylene/70 metal-backed) clinically and radiographically. There were no differences in knee function (Knee Society clinical score, range of motion, stability) or radiographic parameters between the groups. Of the 22 revisions, only three were performed for tibial aseptic loosening (three metal-backed). Ten-year survivorship of the all-polyethylene tibial component was 91.6% with revision for any reason and 100% for aseptic loosening. The metal-backed tibial component survivorship was 88.9% with revision for any reason and 94.3% for aseptic loosening. The contemporary all-polyethylene tibial component functioned equivalently to its monoblock counterpart and was less costly.Level of Evidence: Level I, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Functional Outcome After Revision Hip Arthroplasty: A Metaanalysis

The current study systematically reviews the literature describing patient outcomes after revision total hip arthroplasties using conventional global hip score ratings. Two thousand one hundred thirty-seven English-language articles published from 1966 through 2000 were identified through a computerized literature search and bibliography review. A three-step filter process was used to identify articles to be included in the metaanalysis. Forty-two articles with 2578 patients had data abstracted for the analysis. Metaanalysis of global hip scores was done using a fixed effects model with the assumption that the variances of each measurement were identical across studies. Thirty-nine articles reporting on 46 cohorts progressed through three filters and went to data extraction and analysis. Revision total hip arthroplasty is a reasonably safe and effective procedure for failed hip replacement Based on this exploratory analysis revision hip procedures seem to have comparable longevity, to primary hip replacement but appear to have slightly lower functional outcome (as measured by global hip scores), and slightly higher morbidity and mortality rates than primary procedures. Inconsistent reporting in the original studies limited exploration of other factors that may have affected outcomes.

Excellent survival of all-polyethylene tibial components in a community joint registry.

The advantages of the monoblock design and lower cost have prompted renewed interest in the all-polyethylene tibia in total knee arthroplasty. We prospectively followed patients with all-polyethylene tibial total knee arthroplasties over a 14-year period. Since 1991, 443 total knee arthroplasties using an all-polyethylene tibia component were implanted by 12 surgeons in four hospitals associated with a community registry. One of three designs was used in over 98% of cases. The mean age of the patient population was 77 years and 78% were female. Ninety-three patients died with their prosthesis intact. Three revisions were performed on this population with mean followup of 66.3 months (range, 0-158 months). Kaplan-Meier survival analysis revealed 99.4% survival at 14.3 years with revision for any reason as the end point. With aseptic loosening or wear as the revision reason, survival is 99.7% at 14.3 years. Total knee arthroplasty with one of the three contemporary congruent all-polyethylene tibia designs used in this registry performed extremely well in this population; savings for this group (compared to those with a metal-backed component) was estimated at

Registry Outcomes of Unicompartmental Knee Arthroplasty Revisions

729 per case. If all patients older than 75 years of age in our registry had received an all-polyethylene tibia, the estimated savings for the implant alone would have been