Tibial polyethylene post fractures at ten-years in a bicruciate stabilised (BCS) total knee arthroplasty design.

INTRODUCTION: This short paper reports a potential emerging mode of failure in three patients with a bicruciate stabilised (BCS) total knee arthroplasty. METHODS: Three patients presented to our institution with late instability ten years after undergoing total knee arthroplasty (Journey BCS) and were asymptomatic up to this point. Retrieval analysis was performed by an external body commissioned by the NHS and all three cases were reported to the UK Medicines and Healthcare Products Regulatory Agency (MHRA). RESULTS: Two patients were revised through simple exchange with a polyethylene tibial insert. One patient underwent a full revision of femoral and tibial components. Intra-operative findings revealed that the polyethylene post had fractured in an identical manner in all three cases. Retrieval analysis demonstrated posterior impingement and wear of the polyethylene post resulting in fatigue failure. CONCLUSIONS: This short paper highlights a potential emerging mode of failure with Journey BCS that requires wider dissemination to raise awareness among surgeons and calls for long-term follow up of those patients who received this specific implant. Early revision with polyethylene exchange is a successful treatment in patients when femoral and tibial components are well-positioned and well-fixed.

Fifteen-year survival analysis of an oxidised zirconium total knee arthroplasty.

BACKGROUND: Early studies have found Oxidised Zirconium (OxZr-Nb) total knee arthroplasties to have a low incidence of failure in young, high demand patients. Theoretically this is because they are low friction and hard wearing. However, there are a paucity of studies reporting on the outcome of these implants beyond ten years. The purpose of our study was to present an in-depth 15-year survival analysis of a cemented OxZr-Nb knee arthroplasty. METHODS: Data was collected prospectively and survival analysis undertaken with multiple strict end-points. Complication rates and patient reported outcomes were measured post-operatively. RESULTS: Six hundred and seventeen knee arthroplasties were analysed. Forty-nine patients required a reoperation for various reasons. Aseptic tibial loosening was the most common cause of failure (32.7%), occurring, on average, 2.8 years after the primary procedure. There was only one oxidised zirconium femoral failure recorded. Cumulative survivorship for reoperation for any reason was 91.52% at 15-years. On average, WOMAC (Western Ontario and McMaster University) score improved by 21.2 points at one-year post-surgery, which is beyond the considered minimum clinically important difference. CONCLUSION: This study presents a 15-year survival analysis of a cemented oxidised zirconium knee arthroplasty showing good survivorship over a range of analyses.

Short-Term functional comparison of three total knee arthroplasties-Journey II, Genesis II and Profix.

AIM OF THE STUDY: To compare the outcomes of three knee arthroplasty design philosophies and surface tribology.• A zirconium-surfaced, bicruciate-stabilised implant designed to mimic kinematic movement and improve flexion and outcomes;• A cobalt-chrome surfaced, multi-radius design with built-in femoral external rotation to aid balancing and patella tracking through a deeper trochlea groove;• A zirconium-surfaced, single-radius implant designed on surface conformity, particularly within the patello-femoral joint. METHODS: 313 knee replacements - 103 Journey II, 103 Genesis II and 107 Profix - were statistically assessed at a minimum of 2 years using WOMAC, Oxford and SF-12 scores, and range of movement. RESULTS: There was no difference between the actual or unit change in WOMAC scores (p = 0.140 and p = 0.287), SF-12 physical (p = 0.088) or mental scores (p = 0.975) between the three implants; or between the actual or unit change in Oxford score (p = 0.912 and p = 0.874) for the Journey II or Genesis II. The Journey II produced more flexion and range of movement than the Genesis II (p < 0.001 and p = 0.018) and Profix (p < 0.001 and <0.001) with no difference between the latter two (p = 0.402 and 0.568); with no difference in extension between the three implants (p = 0.086). There was no difference between those with or without a resurfaced patella. CONCLUSION: The three design philosophies and surfaces yielded no difference in outcome scores at 2 years post-operatively. The Journey II demonstrated better post-operative flexion. Resurfacing the patella did not alter the outcome scores or flexion.

The Journey Bicruciate Knee Replacement: Design Modifications Yield Better Early Functional Results and Reduce Complications.

The Journey-I total knee replacement was designed to improve knee kinematics but had several complications including early dislocation. The Journey-II modification was introduced to reduce these while maintaining high function. To assess whether the modified Journey-II prosthesis has succeeded in its designers aims, we undertook an observational study of prospectively recorded data to analyze and compare the two knees. A total of 217 Journey-I and 129 Journey-II knees were identified from the department's prospectively collated registry and were assessed at 1 year by a comparative statistical analysis using numerous factors including pain, functional activity, physical assessment, Short Form-12 (SF-12), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and Oxford scores. The statistical tests included Chi-square, Wilcoxon's rank and Mann-Whitney U-tests with the level of significance set at p < 0.05. There was a variation in primary patella resurfacing between the two groups with 14.3% in the Journey-I cohort and 66.7% in the Journey-II cohort. Both replacements demonstrated excellent postoperative function, but the Journey II performed significantly better than Journey I with fewer complications (37 vs. 10) and better improvement in almost all clinical scores including pain (p < 0.01), mobility outcomes (p = 0.018), Oxford (p = 0.004), and WOMAC (p = 0.039) scores but not with flexion improvement and SF-12 score. There was significant improvement in patellofemoral pain postoperatively in both the Journey I (p = 0.011) and Journey II (p = 0.042) arthroplasty; however the primarily resurfaced patella in a Journey-II implant had better postoperative scores. The main complication of dislocation in the Journey I was not seen in the modified Journey-II implant with stiffness requiring intervention reduced in Journey II. These results suggest that the Journey II has improved short-term clinical outcomes compared with Journey I with reduction of dislocation and other complications.

Single Use Instruments for Implanting a Contemporary Total Knee Arthroplasty System Are Accurate, Efficient, and Safe.

BACKGROUND: Single use instruments (SUI) is a potential mechanism to improve efficiency and reduce cost in total knee arthroplasty (TKA). New technology requires patient safety and surgical accuracy. A multi-center study of SUI vs reusable mechanical instrumentation (RUI) for a TKA system compared implant placement accuracy and operating room (OR) efficiency. METHODS: Four surgeons implanted 88 primary TKAs, N = 44 RUI and N = 44 SUI. Accuracy was measured radiographically at 3 months. The primary endpoint was non-inferiority of absolute value of mechanical axis alignment. Radiographic endpoints, OR times, and adverse events were also evaluated. RESULTS: Seventy-five subjects completed the study (41 SUI/34 RUI). The primary endpoint non-inferiority of SUI vs RUI was met, with no significant difference between SUI and RUI in most radiographic parameters (distal femoral varus-valgus, proximal tibial varus-valgus, tibial slope, or subjects within 3° of target); there was a slight difference in femoral component flexion angle (P = .015). SUI and RUI mean (SD) OR set-up times were 18.8 (10.03) and 26.7 (6.93) (P <.001), and surgical times (first incision to last stitch) were 64.6 (16.95) and 60.5 (19.01) (P = .295), respectively. Differences in OR clean-down and anesthesia were not significant. There were no revisions, and there was no significant difference in the number of reported adverse events. CONCLUSION: SUI resulted in similar accuracy of implant placement to RUI with decreased OR set-up time and no increase in adverse events. These results support the safety and efficacy of SUI for performing TKA. Further analysis of potential economic and technical advantages is warranted.

The Medium-Term Survival Analysis of an All-Polyethylene Tibia in a Single-Series Cohort of Over 1000 Knees.

BACKGROUND: Total knee arthroplasty is a successful elective orthopedic procedure with an increasing number being undertaken. Original knee arthroplasties used an all-polyethylene tibia; however, with concerns over tibial loosening, the trend moved toward the metal-backed variety. Modern designs providing more conformity and changes in manufacturing of the polyethylene make it an equivalent but cheaper option. METHODS: We analyzed the medium-term outcome in 1092 patients with an all-polyethylene tibial component in their total knee arthroplasty. RESULTS: Twenty-six patients had further surgery on their knee for a variety of reasons. Assessing reoperation for any reason, the 7-year survival rate was 96.96% with an overall infection rate of 0.37%. Seven-year survival analysis using aseptic loosening as a criteria was 99.28%. Both the Short Form 12 physical score and Western Ontario and McMaster Universities Osteoarthritis Index score significantly improved and was sustained at 7 years. Body mass did not correlate to either outcomes or complications. CONCLUSION: An all-polyethylene tibia in a total knee arthroplasty has good outcome data and high patient satisfaction with good survivorship in the medium term, coupled with potential cost-saving benefits.

Manipulation under anaesthetic following total knee arthroplasty: Predicting stiffness and outcome.

PURPOSE: A stiff total knee replacement can severely limit a patient's post-operative function, but there remain few prospective trials identifying those patients at risk, nor the efficacy of manipulation. We analysed our prospectively collected database to assess predictors of stiffness and outcomes following manipulation. METHODS: Using prospectively collected knee arthroplasty data, including preoperative and post-operative range of knee movement, SF-12 (physical and mental) and The Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores, patients requiring manipulation were compared to a matched group of patients not requiring manipulation, with a detailed statistical analysis undertaken to assess potential risk factors and the post-manipulation outcome. RESULTS: Of the 1313 arthroplasty patients, 69 required manipulation. Patients with less than 80° of flexion at discharge, diabetes or on warfarin were more likely to require manipulation, but flexion at discharge was the overwhelming predictive factor for stiffness. Forty per cent of the range of movement gained during manipulation was maintained at 1 year, with earlier manipulation deriving greater improvements. While the WOMAC scores improved post-manipulation, there was no significant difference in either of the SF12 scores. CONCLUSION: Flexion at discharge is the overwhelming predictive factor for the requirement for manipulation.

Mid- to long-term survivorship of oxidised zirconium total knee replacements performed in patients under 50years of age.

BACKGROUND: Oxidised zirconium has the wear properties of ceramic with the breakage resistance of metal. This results in less wear and is of benefit to younger, higher demand patients. We report the short- to mid-term survival of 103 Profix zirconium total knee replacements performed in patients under 50years of age at time of surgery. METHODS: Data was collected prospectively and survival analysis undertaken with strict end points used. SF (Short Form) 12 and WOMAC (Western Ontario and McMaster University) scores were recorded at pre-operatively and at twelve months, one, three, five, seven and ten years. RESULTS: The average age at operation was 43.21years (range 20-50years) with a mean follow-up of 8.56years (range five to 15years). No patients died with one patient lost to follow-up after seven year review. The mean WOMAC score improved from 53 to 29, and the mean SF12 physical component improved from 29 to 36. The five year survivorship for implant related complications was 99.03% (95% CI 94.64-100.0) due to tibial component aseptic loosening at year one. Reoperation for any cause at five years including stiffness was 94.09% (95% CI 88.69-98.11). Forty-four patients were at least ten years post-operative at the time of analysis, with no aseptic loosening of either component giving 10year femoral component survival of 100% and all cause revision of 95.4%. The only zirconium femoral failure was at 12years. CONCLUSIONS: Our data shows excellent mid-term survivorship of oxidised zirconium total knee replacements in younger, higher demand patients.

Five year survival analysis of an oxidised zirconium total knee arthroplasty.

BACKGROUND: Zirconium total knee arthroplasties theoretically have a low incidence of failure as they are low friction, hard wearing and hypoallergenic. We report the five year survival of 213 Profix zirconium total knee arthroplasties with a conforming all polyethylene tibial component. METHODS: Data was collected prospectively and multiple strict end points were used. SF12 and WOMAC scores were recorded pre-operatively, at three months, at twelve months, at 3 years and at 5 years. RESULTS: Eight patients died and six were "lost to follow-up". The remaining 199 knees were followed up for five years. The mean WOMAC score improved from 56 to 35 and the mean SF12 physical component score improved from 28 to 34. The five year survival for failure due to implant related reasons was 99.5% (95% CI 97.4-100). This was due to one tibial component becoming loose aseptically in year zero. CONCLUSIONS: Our results demonstrate that the Profix zirconium total knee arthroplasty has a low medium term failure rate comparable to the best implants. Further research is needed to establish if the beneficial properties of zirconium improve long term implant survival.

Retrospective analysis of perioperative ketorolac and postoperative bleeding in reduction mammoplasty.

PURPOSE: We conducted a retrospective review following concerns involving a suspected increase in the requirement for surgical re-exploration for hematoma evacuation when ketorolac was administered perioperatively in patients undergoing reduction mammoplasty. METHODS: Following ethics approval, a retrospective chart review was conducted of all patients who underwent reduction mammoplasty at our two institutions from the time ketorolac became available in 2004 until surgeons requested its use discontinued in 2007. The data we collected included patient demographics, ketorolac administration, requirement for surgical re-exploration, documented hematoma formation not requiring surgical re-exploration, and excessive bleeding in the perioperative period. Three hundred and seventy-nine patient records were reviewed; 127 of the patients received a single intravenous dose of ketorolac (15 or 30 mg), and 252 of the patients did not receive ketorolac. RESULTS: Patients who received ketorolac were at an increased risk of requiring surgical re-exploration for hematoma evacuation (relative risk [RR] = 3.6; 95% confidence interval [CI], 1.4 to 9.6) and hematoma formation not requiring re-exploration (RR = 2.2; 95% CI, 1.3 to 3.6). CONCLUSIONS: A single perioperative intravenous dose of ketorolac was associated with a greater than three-fold increase in the likelihood of requirement for surgical hematoma evacuation. Our data suggest that it may be prudent to consider carefully whether the potential risks associated with the use of ketorolac outweigh the potential benefits of using ketorolac in patients undergoing reduction mammoplasty.

Atypical fibroxanthoma: clinicopathologic determinants for recurrence and implications for surgical management.

BACKGROUND AND OBJECTIVES: Atypical fibroxanthoma (AFX) is an uncommon skin tumor occurring primarily in the head and neck region of elderly Caucasian males. Treated with local excision, the disease is thought to be fairly benign but can occasionally demonstrate aggressive local recurrence as well as distant metastasis. METHODS: Seventy-one cases of AFX were reviewed, representing all patients presenting to the Health Sciences Centre of South Eastern Ontario with the diagnosis of AFX in the period 1989-2008. Demographic and pathologic data were obtained from patient charts for analysis. RESULTS: Mean age at presentation was 76, with a male:female ratio of 4:1. Recurrence occurred in 10 patients after an average period of 7.3 months. Three recurrent lesions went on to distant metastasis, on average 14.3 months after initial presentation. The remaining 60 tumors did not recur. Histologically, tumor extending beyond the dermis into the underlying adipose and muscular tissue had a 29.4% chance of local recurrence and an 11.8% chance of metastasis compared to lesions confined to the dermis only (9.3% and 1.8%). CONCLUSIONS: While the majority of AFX presentations are benign, there is a real possibility of metastatic spread. Invasion beyond the dermis and a rapid rate of recurrence are suggestive of a more aggressive clinical course.

Development of an in vitro model to investigate joint ochronosis in alkaptonuria.

OBJECTIVES: Alkaptonuria (AKU) is a genetic disorder caused by lack of the enzyme responsible for breaking down homogentisic acid (HGA), an intermediate in tyrosine metabolism. HGA is deposited as a polymer, termed ochronotic pigment, in collagenous tissues. Pigmentation is progressive over many years, leading to CTDs including severe arthropathies. To investigate the mechanism of pigmentation and to determine how it leads to arthropathy, we aimed to develop an in vitro model of ochronosis. METHODS: Osteosarcoma cell lines MG63, SaOS-2 and TE85 were cultured in medium containing HGA from 0.1 µM to 1 mM. Cultures were examined by light microscopy and transmission electron microscopy, and Schmorl's stain was used to detect pigment deposits in vitro, following the observation that this stain identifies ochronotic pigment in AKU tissues. The effects of HGA on cell growth and collagen synthesis were also determined. RESULTS: There was a dose-related deposition of pigment in cells and associated matrix from 33 µM to 0.33 mM HGA. Pigmentation in vitro was much more rapid than in vivo, indicating that protective mechanisms exist in tissues in situ. Pigment deposition was dependent on the presence of cells and was observed at HGA concentrations that were not toxic. There was an inhibition of cell growth and a stimulation of type I collagen synthesis up to 0.33 mM HGA, but severe cell toxicity at 1 mM HGA. CONCLUSION: We have developed an in vitro model of ochronosis that should contribute to understanding joint destruction in AKU and to the aetiology of OA.

Median artery forearm flap.

Vascular anomalies of the forearm can impact the planning and elevation of fasciocuteanous flaps from this region. This report describes the elevation of a free forearm flap based on an anomalous persistent median artery for a case of oropharyngeal reconstruction. The incidence, embryology and significance of vascular anomalies with respect to the forearm flap are reviewed.

Interstitial fluid pressure in free vascularized skin flaps of the rat epigastrium.

The purpose of this study was to observe the magnitude and time course of changes in tissue edema in experimental free flaps. Thirty female Sprague Dawley rats underwent elevation and orthoptic transplantation of free epigastric skin flaps. Using a modified "wick in needle" technique, interstitial fluid pressure (IFP) was measured in the flaps at various times up to 2 weeks postoperatively. Increases in IFP to positive values were seen by 12 hours. IFP remained elevated for 3 to 5 days, after which they gradually returned to control values by 2 weeks. This is the first study to follow the time course and magnitude of changes in IFP and edema in free flaps. It is a useful animal model by which the hemodynamic effects of physical and pharmacological manipulation of flaps can be studied.

Effect of lidocaine and epinephrine on Staphylococcus aureus in a guinea pig model of surgical wound infection.

Postoperative wound infection, most often with, is of ubiquitous concern in surgical practice, occurring in an average of 1.5 to 5 percent of all procedures. The antimicrobial properties of local anesthetics have been documented over the past 25 years by in vitro studies. This study evaluates the effects of lidocaine preparations on in an in vivo setting. In a wound infection model using live albino guinea pigs, inoculum was introduced for the reproducible bacterial colonization of clean surgical wounds. One of two sites on the dorsum of each animal was infiltrated with a commercial lidocaine preparation (with and without epinephrine) prior to inoculation with (10 cfu/ml). The other site, inoculated with without preinfiltration with lidocaine, served as the control. Cultures from the sites treated with lidocaine were then compared with cultures from the control sites. All control sites had a consistent presence >or=10 cfu/ml, the threshold for bacterial inhibition of wound healing. Infiltration of the wound with 2 ml of 2% lidocaine prior to inoculation was associated with an average decrease in bacterial count of >70 percent ( n= 19). On the other hand, the addition of epinephrine (1:100,000) to lidocaine was associated with a 20-fold in bacterial counts compared with control values ( n= 10). This is the first study to demonstrate inhibition of by a local anesthetic agent in an in vivo model of a surgical wound. This information suggests a possible role for local anesthetics in prophylaxis against surgical wound infection.