Introduction

With the introduction of new technology in orthopaedics, surgeons must balance anticipated benefits in patient outcomes with challenges or complications associated with surgical learning curve for the technology. The purpose of this study was to determine whether the surgeon learning curve with a new multi-radius primary TKA system (primary TKA implant and instruments) designed for surgical team ease would impact clinical outcomes, surgical time and complications.

With the introduction of new technology in orthopaedics, surgeons must balance anticipated benefits in patient outcomes with challenges or complications associated with surgical learning curve for the technology. The purpose of this study was to determine whether surgeon learning curve with a new multi-radius primary TKA system and instruments designed to improve surgical team ease would impact clinical outcomes, surgical time, and complications.

From November 2012 to July 2015, 2369 primary TKAs were prospectively enrolled in two multicentre studies across 50 sites in 14 countries with a new knee system (NEW-TKA) evenly balanced across four configurations: cruciate retaining or posterior stabilised with either fixed bearing or rotating platform (CRFB, CRRP, PSFB, PSRP). 2128 knees had a<1 year visit and 1189 had a minimum 1 year visit. These knees were compared to a reference dataset of 843 primary TKAs from three manufacturers in the same four configurations with currently available products (CA-TKA). Demographics for NEW-TKA and CA-TKA were similar and typical for primary TKA. Operative times, clinical outcomes and a series of five patient reported outcomes were compared for NEW-TKA vs. CA-TKA. The first 10 New-TKA subjects for each surgeon were defined as learning curve cases (N=520) and were compared to all later subjects (N=1849). Patient reported outcome measure and clinical outcome analyses were covariate adjusted for patient demographics, pre-op assessment and days post-op.

Mean (SD) surgical time for NEW-TKA learning curve cases was 79.1 (24.3) minutes, which reduced thereafter to 73.6 (24.3) (p=0.002). Beyond 10 cases, there was a continued reduction in NEW-TKA surgical time (R-Squared = 0.031). After 10 cases, surgical time was on par with the mean (SD) 71.9 (21.6) for CA-TKA (p=0.078). PROM outcomes of the first 10 learning curve cases for NEW-TKA were not statistically different from later cases at less than 1 year or later when adjusted for relevant covariates including configuration, patient demographics, pre-op functional status, and time post-op (p-values > 0.01). PROM outcomes for NEW-TKA vs. CA-TKA under the same covariate adjustments showed a trend favoring KOOS ADL, Symptoms, and Sport and Recreation subscores at minimum 1 year (p-values < 0.01). The incidence of intraoperative operative site complications was 1.3% for the NEW-TKA learning curve cases which was similar to the 0.6% rate for historical CA-TKA (p=0.231) and the intraoperative complication rate for the NEW-TKA later cases was consistent with learning curve cases (p=0.158).

The introduction of new implants into the market place needs to have adequate data to support that they are safe and effective. Except for a minor increase in surgical time during the first 10 patients, this study found that surgeon learning curve with this new primary TKA system does not adversely affect patient short term outcomes and complication rates.

Introduction

Cross-linked polyethylene in total hip arthroplasty has demonstrated excellent long-term wear resistance, leading to its acceptance as the standard bearing used in hip replacement. Adoption in knee replacement has been tentative, as the cross-linking process can decrease the polyethylene mechanical properties. The current study's purpose was examining survivorship of a fixed bearing knee replacement system featuring a moderately cross-linked polyethylene (MXLK) bearing, a cobalt chrome (CoCr) tibial tray with a highly polished top surface, and a new polyethylene-to-tray locking mechanism. The MXLK is made of ultra-high molecular weight GUR1020 resin irradiated with 5 Mrad gamma radiation, followed by a free radical quenching remelting annealing process, above the 135 degree melting point, that provides wear and fatigue resistance, and oxidative stability.

The PFC Sigma Cobalt Chrome Sigma (PFCSCC) was introduced in 2006, an update of the PFC Sigma designed to reduce backside wear. To help identify any significant early failures following its introduction, we prospectively identified all recipients over a one-year period. The patient's clinical, demographic and radiographic data, American Knee Society scores (AKSS), Oxford Knee scores (OKS) and SF-12 scores was recorded pre-operatively and at one, three and five years. 233 patients underwent 249 primary knee arthroplasties with the PFCSCC. Seventeen patients (19 knees) died and 29 patients (30 knees) were also lost to follow up at the five year point. The mean age was 66.6 (34–80) with 47.6% of the cohort being male. The mean five year follow-up was 1836 days (1530–2307). Five knees (2.2%) were revised for infection and three were revised for pain. The 5–year cumulative survival rate was 96.6% for any failure and 98.6% for aseptic failure. AKSS 32.6 (0–86.6) preoperatively, 80.7 (29–95) 5 years P < 0.001. OKS was 39.0 (22–53) preoperatively, 23.5 (4.7–42.3) 5 years P < 0.001. These results demonstrate a good early survivorship when compared to the old design PFC Sigma, however further follow-up to ten years is required.

Blood loss following total hip replacement is a major contributor to increase morbidity and length of stay. Various techniques have been described to reduce its occurrence. We now follow a set protocol, combining rivaroxaban for thrombo-prophylaxis and tranexamic acid to reduce immediate postoperative bleeding.

Introduction:

Two-stage revision is a widely accepted and performed intervention for septic total knee arthroplasty (TKA), with an infection eradication rate exceeding 90% in most studies. The ‘2-in-1’ single stage revision has recently been reported to have favourable results.

Current literature comparing the effect on body mass index (BMI) on the outcome of total hip replacements (THR) is inconclusive. To describe the effect of BMI on THR over the first five years.

We prospectively recruited 1,617 patients undergoing primary THR for osteoarthritis and followed them up at 5 years, recording, dislocations, revisions, deep and superficial infections, Harris Hip scores (HHS) and SF-36. A multivariate analysis was performed to identify if BMI is an independent predictor of adverse outcome.

148 (9%) patients had a BMI >35. 6.8% of patients with a BMI >35 had a dislocation by 5 year post op compared with 3.2%BMI 30–34.9, 2% BMI 25–29.9 and 1.5% BMI<25 (p=0.03) Superficial infections 14.2% BMI >35, 4.4% BMI <25. In SF 36 scores only Mental Health and change in health had no significant differences with an increase in BMI having a statistically significant decrease in all other SF scores. HHS had a mean improvement of 45.1 at five years with an expected loss of 0.302 HHS points (95% CI0.440–0.163) per 1 point BMI increase. There was no significant difference in deep infections, mortality <3 months, revision rates or length of stay.

The most significant risk in increasing BMI is the dislocation rate, possibly representing increased technical difficulty in larger patients. Whilst increasing BMI has a reduced HHS and SF16 score, the overall benefit is still positive.

The risk of venous thrombo-embolism (VTE) is high in orthopedics. Oral direct factor Xa inhibitors have been introduced to help reduce the incidence of VTE. To reduce post-operative bleeding antifibrinolytics are used. We aimed to ascertain the effect of two drugs on post operative bleeding and transfusion requirements.

We prospectively recorded patient demographics, operative details, complications, transfusion incidence and VTE incidence in TKR patients. We also sent out questionnaires to patients asking about wound bleeding and VTE. All patients were given 10mg Rivaroxaban 8 hours post operatively and then OD for 14 or 35 days. Patients given tranexamic acid were given 500mg IV, 5 minutes prior to wound closure at the discretion of the surgeon. VTE was Deep Vein Thrombus or Pulmonary Embolism confirmed by Doppler or CTPA. Minor bleed was categorized as dressing soakage or reported wound leakage, major bleed as hematoma requiring revision within 30 days.

509 patients underwent TKR: 200 (39%) received Rivaroxaban only (Group 1), 296 (58%) also received tranexamic acid (Group 2). 13 (3%) patients had no data available. Five patients had a VTE: 4 (2%) in Group 1, 1 (0.3%) in Group 2 [P<0.05]. 39 patients had a minor bleed: 17 (8.5%) in Group 1, 22 (7.4%) in Group 2 [P=0.5]. 2 patients had major bleeds: 1(0.5%) in Group 1 and 1(0.33%) in Group 2 [P=0.69]. There were 30 blood transfusions: 21 (10.5%) in Group 1, 9 (3%) in Group 2 [P<0.0001].

We have demonstrated a reduced requirement for blood transfusions in the tranexamic acid group. However our results, whilst they show a trend towards decreased minor and major bleeding rates, are not significant and require larger studies looking at wound bleeding and leakage.

We set out to demonstrate the 10-year survivorship of the PFC sigma TKA in a young patient group.

Demographic and clinical outcome data were collected prospectively at 6 months, 18 months, 3 years, 5 years and 8–10 years post surgery.

The data were analysed using Kaplan Meier survival statistics with end point being regarded as death or revision for any reason.

203 patients were found to be < 55 years at the time of surgery. Four patients required revision and four patients died. Another four patients moved away from the region and were excluded from the study.

A total of 224 knees in 199 patients (101 male and 98 females.) 168 patients had a diagnosis of Osteoarthritis and 28 with inflammatory arthritis. Average age 50.6 years range 28–55 years (median 51). Ten-year survivorship in terms of revision 98.2% at ten years 95% confidence interval.

Our results demonstrate that the PFC Sigma knee has an excellent survival rate in young patients over the first 10 years. TKR should not be withheld from patients on the basis of age.

The DuPuy Sigma total knee arthroplasty (TKA) is a modification of the well-established Press Fit Condylar (PFC) TKA and is used extensively in the UK and worldwide. This study reports the first 10-year clinical and radiological follow-up data for the Sigma PFC.

A total of 235 consecutive Sigma TKAs were performed in 203 patients between October 1998 and October 1999, in our unit. Patients were seen at a specialist nurse-led clinic 1 week before admission and at 6 months, 18 months, 3 years, 5 years and 7-10 years after surgery. Data was recorded prospectively at each clinic visit.

Of 235 knees, 171 (147 patients) were alive at 10 years. Twelve were lost to follow up. Eight knees (3.4%) were revised; four for infection and four underwent isolated change of polyethylene insert. Ten-year survival with an end point of revision for any reason was 95.9%, and with an endpoint of revision for aseptic failure was 98.7%. The mean American Knee Society score was 62 at 8-10 years compared with 31 out of 100 pre-operatively.

Our results show that the PFC Sigma knee arthroplasty performs well over the first 10 years post-implantation.

The aim of this study was to compare the long-term outcome from total knee replacement (TKR) in young versus old patients in terms of pain and functional outcome.

We used our arthroplasty database, which recorded prospectively pain and American Knee Society scores at regular intervals over ten years after TKR. The procedures used a modern, cemented resurfacing type cruciate retaining prosthesis. A cohort of young patients (≤55 years) was identified. A control group of patients ≥ 56 was identified, matching for ASA, body mass index and underlying condition. Change over time was analysed using a factorial repeated measures ANOVA test, which allowed for investigation of difference between groups. 40 Knees in 26 patients were identified. 2 patients died prior to follow up, 2 were revised within the study period (1 for infection at 2 years and one for change of poly at 7 years) and a further 4 were lost to follow up. 7 knees could not be matched and were excluded. This left a study group of 24 young and 24 older knees. Pain scores (p=0.025) and American Knee Society “Knee” (p<0.001) and “Function” (p<0.001) scores changed significantly over time. There were however no statistical differences over the 10-year period in pain (p=0.436) and knee performance (0.618) but overall function was higher throughout the period in the younger group (=0.004).

We conclude that Knee replacement in younger patients produces similar outcomes in terms of pain and function compared with older patients and TKR should not be withheld purely on account of age.

The risk of venous thrombo-embolism (VTE) is high in orthopaedics. Oral direct factor Xa inhibitors have been introduced to help reduce the incidence of VTE. To reduce post-operative bleeding antifibrinolytics are used. We aimed to ascertain the effect of two drugs on post-operative bleeding and transfusion requirements.

We prospectively recorded patient demographics, operative details, complications, transfusion incidence and VTE incidence in TKR patients. We also sent out a questionnaire to patients asking about wound bleeding and VTE. All patients were given 10mg Rivaroxaban 8 hours post operatively and then once a day for 14 days. Patients given tranexamic acid were given 500mg IV, 5 minutes prior to wound closure at the discretion of the surgeon. VTE was confirmed by Doppler or CTPA as Deep Vein Thrombus or Pulmonary Embolism. Minor bleed was categorised as dressing soakage or reported wound leakage, major bleed as haematoma requiring revision within 30 days.

509 patients underwent TKR: 200(39%) only received Rivaroxaban (Group 1), 296(58%) also received tranexamic acid (Group 2). 13(3%) of patients had no data available. 5 patients had a VTE: 4 (2%) Group 1, 1 (0.3%) Group 2 (P<0.05). 39 patients had a minor bleed: 17 (8.5%) Group 1, 22 (7.4%) Group 2 (P=0.5). 2 patients had major bleeds: 1 (0.5%) Group 1, 1 (0.33%) Group 2 (P=0.69). Blood transfusions 21: (10.5%)Group 1, 9 (3%) Group 2 (P<0.0001).

We have demonstrated a reduced requirement for blood transfusions in the tranexamic acid group. However our results whilst they show a trend towards decrease bleeding rates in both the minor and major bleeds are not significant, requiring larger studies looking at wound bleeding and leakage.

Aim

To compare the results of total knee replacement in a consecutive series of morbidly obese patients (body mass index (BMI) > 40 kg/m²) with a matched group of non-obese (BMI< 30 kg/m²) patients.

Pre-operative co-morbidities such as known coronary artery disease have commonly deemed a patient at ‘high risk’ for primary elective Total Hip Arthroplasty (THA).

We prospectively collected data on 1744 patients who underwent primary elective THA between 1998 and 2004. 273 had a history of cardiac disease defined as a previous hospital admission with a diagnosis of angina pectoris or myocardial infarction. 594 patients had hypertension defined as that requiring treatment with antihypertensives. We also had data on pre-operative age, sex and body mass index (BMI).

There was no statistically significant increase in early mortality at 3 months with a history of cardiac disease or hypertension and this remained so when adjusting for the other factors in a multivariate analysis. Sex or BMI also did not have a statistically significant effect on the risk of death within 3 months. Increasing age was the only significant risk factor for early mortality (P<0.001).

Longer term mortality at 2 and 5 years in relation to these factors was also examined. Statistical analysis revealed that coronary history now showed a highly significant association (P<0.001) with long term mortality, in patients who survived more than 3 months. 95% confidence intervals for percentage mortality at 5 years were 9.7 - 21.7 with a cardiac history compared to 4.8 - 8.8 without a cardiac history. This remained significant (P=0.002) when adjusted for the other factors. Hypertension continued to have no effect, nor did BMI. Age remained a significant risk factor. Females had a slightly lower long term death rate than males, following THA.

The overall long term mortality following THA was less than expected from the normal population, even in the subgroup with a coronary history.

This study will assist clinicians when advising patients seeking primary elective THA, who have one of these common risk factors.

Introduction

We report the results of a prospective study of 1349 patients undergoing 1509 total knee replacements, identifying factors increasing the risk of infection.