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:

Proponents of quadriceps-sparing (QS) subvastus approach for total knee arthroplasty (TKA) suggest short-term advantages including better early functional results, less pain and shorter hospital stay. However, because of potentially reduced visibility and exposure, the QS approach may compromise component alignment – an important surgeon-controlled outcome affecting implant longevity. The purpose of this study was to determine if a QS approach resulted in compromised component alignment compared to a medial parapatellar arthrotomy (MPPA), when both were performed with contemporary minimally invasive surgery (MIS) principles including small incision (≤ 15 cm), MIS instrumentation, patellar subluxation without eversion, and in situ bone cuts.

INTRODUCTION

Clinical trials have generally failed to demonstrate superior clinical effectiveness of minimally invasive surgical approaches for total knee arthroplasty (TKA). The hypothesis of the current study was that avoiding incision of the quadriceps tendon would result in a significantly faster recovery of ambulatory function after total knee arthroplasty, compared to a technique that incised the quadriceps tendon.

Antibiotic-impregnated bone cement (ABC) is infrequently used in the North America for primary total hip arthroplasty (THA) due to concerns with cost, performance, and the possible development of antibiotic resistance. The purpose of this study is to examine the cost-effectiveness of using ABC in primary THA for osteoarthritis compared to the use of cement without antibiotics.

A Markov decision model was used to determine if ABC is a cost-effective strategy for primary THA in patients with osteoarthritis. The model tabulates costs and quality adjusted life years (QALYs) accumulated by each patient to evaluate the cost-effectiveness of each strategy. Rates of revision for infection and aseptic loosening were estimated from the Norwegian Arthroplasty Register, and were used to determine the probability of transitioning to a revision arthroplasty for either infection or aseptic loosening. The model was also used to evaluate the cost-effectiveness of ABC when only revisions for infection are considered. Peri-operative mortality rates, utilities, and disutilities were estimated from the arthroplasty literature. Costs were also estimated from the literature using in-hospital resource use as the method of measurement for primary THA. The additional cost of using ABC ($600) was then added to the average cost of the initial procedure ($21,654).

ABC is less expensive and more effective than standard cement when all revisions are considered, making the use of ABC the dominant strategy. When only revision for infection is considered, the use of ABC has an incremental cost-effectiveness ratio (ICER) of $37.335 per QALY compared to cement without antibiotics – which compares favorably with the cost-effectiveness of accepted medical procedures. Sensitivity analyses reveal that for all revisions the additional cost of ABC would need to be greater than $1500, or the average age of patients undergoing primary THA would need to be greater than eighty-three before the use of ABC would cost more than $50,000 per QALY gained. When only revision for infection is considered, the additional cost of ABC would need to exceed $650 before the cost of ABC would exceed $50,000 per QALY gained.

Use of ABC for primary THA is cost-effective over a wide range of assumptions. Notably, when all revisions are considered, ABC is less costly and more effective than use of standard cement over the life span of the patients.

We examined the relationship between waiting times for ACL surgery and the need for meniscal surgery at time of reconstruction. Using the Provincial Billing Database we identified 3812 ACL reconstructions between 1999–2001. Patients waited on average four hundred and twenty-two days from initial medical visit to reconstruction. 1722 patients (45%) required meniscal surgery with the ACL procedure. The delay to surgery was: two hundred and fifty-one days (no meniscal surgery required), four hundred and thirteen days (meniscal repair) and six hundred and seventy-six days (meniscectomies). This difference was significant, p< .01, ANOVA. The rate of meniscal surgery per time period was also significantly different: 17% if < 3months, 57% if > 6months. Our present Health Care policies place patients at risk of requiring avoidable meniscal surgery and developing osteoarthritis.

The purpose of this study was to examine the relationship between waiting times for ACL surgery and outcome.

The outcome measure was the need for meniscal surgery at the time of ACL reconstruction. The Provincial Data Base Billing information was reviewed for ACL reconstruction between 1999–2001. The simultaneous need for a meniscal procedure was noted. Tracking back in time, all demographic, diagnostic and interventional billing data (ICD & Visit billing code) preceding their ACL surgery was recorded.

Between 1999–2001, 3812 ACL reconstructions were identified. Of these, 1722 patients required a meniscal procedure (45%). On average, patients waited over four hundred and twenty-two days from injury to reconstruction. Patients who did not require any meniscal procedure waited on average two hundred and fifty-one days, meniscal repairs waited four hundred and thirteen days, while meniscectomies waited six hundred and seventy-six days. More importantly, the need for a meniscal procedure correlated with the timing of surgery: 17% of those reconstructed < three months from injury had a significant meniscal injury, compared to 57% at > six months. Almost half of which (48%) required a meniscectomy for significant meniscal injury. These differences all attained statistical significance (p< 0.01).

Previous reports suggest that the ACL-deficient knee increases the risk of meniscal injury and meniscal incompetence hastens OA. Our data show a progressive increase in the rate to meniscal surgery, and meniscal injury complexity with time. These delays and rates are higher than the ones proposed in the literature.

It appears that the experience in our Province simply reproduces (rather than improves upon) the natural history of the ACL injury. We postulate restricting access to specialists and to surgery place the patient at risk for requiring avoidable surgery and developing osteoarthritis

To reduce the reported 1% mortality rate in the first month because of embolism and cardiopulmonary complications, intraoperative Swan Ganz catheter monitoring has become routine at our institution for patients undergoing bilateral total knee arthroplasties. By calculating the pulmonary vascular resistance, patients at risk for fat embolism syndrome can be identified after the first of single-stage, sequential bilateral total knee arthroplasties prior to proceeding to the second arthroplasty. This study evaluates the reliability of quantitative parameters for canceling the second side.

The purpose of this study was to evaluate the reliability of quantitative criteria for proceeding with the second side of single-stage, sequential bilateral total knee arthroplasties.

Our experience did enable this procedure to be performed in a consistently safe manner. Bilateral total knee replacements have a reported 1% mortality rate in the first month largely because of embolism and cardiopulmonary complications. Adhering to a monitoring protocol that allows this risk to be minimized enables surgeons to offer this treatment to the many patients with bilateral gonarthrosis.

One hundred and sixty-three consecutive patients who had one-stage, sequential, bilateral total knee arthroplasties were monitored prospectively with a pulmonary artery Swan Ganz catheter. The pulmonary vascular resistance was calculated before skin incision, ten minutes after deflation of the tourniquet following completion of the first arthroplasty, and again after the second knee replacement. The second knee replacement was cancelled in seventeen patients because the pulmonary vascular resistance after the first arthroplasty had either doubled from baseline, or was above 200 dyne/second/cm⁵. Of those who had their bilateral arthroplasties performed, 2% developed signs of fat embolism syndrome, while in the group in whom the second side was cancelled, a 6% incidence was observed. The mortality rate for the entire cohort was 0%. Intraoperative monitoring with a pulmonary artery catheter reliably indicates which patients are at increased risk for pulmonary vascular compromise after one total knee replacement and therefore are not eligible for a second total knee replacement at the same operation.