Martin Roche

A new method for defining balance: promising short-term clinical outcomes of sensor-guided TKA.

Recently, technological advances have made it possible to quantify pounds of pressure across the bearing surface during TKA. This multicenter evaluation, using intraoperative sensors, was performed for two reasons: 1) to define balance 2) to determine if patients with balanced knees exhibit improved short-term clinical outcomes. Outcomes scores were compared between balanced and unbalanced patients. At 6-months, the balanced cohort scored 172.4 and 14.5 in KSS and WOMAC, respectively; the unbalanced cohort scored 145.3 and 23.8 in KSS and WOMAC (P < 0.001). Out of all confounding variables, balanced joints were the most significant contributing factor to improved postoperative outcomes (P < 0.001). Odds ratios demonstrate that balanced joints are 2.5, 1.3, and 1.8 times more likely to achieve meaningful improvement in KSS, WOMAC, and activity level, respectively.

Accuracy of Dynamic Tactile-Guided Unicompartmental Knee Arthroplasty

Unicompartmental knee arthroplasty (UKA) can achieve excellent clinical and functional results for patients having single-compartment osteoarthritis. However, UKA is considered to be technically challenging to perform, and malalignment of implant components significantly contributes to UKA failures. It has been shown that surgical navigation and tactile robotics could be used to provide very accurate component placement when the bones were rigidly fixed in a stereotactic frame during preparation. The purpose of this investigation was to determine the clinically realized accuracy of UKA component placement using surgical navigation and tactile robotics when the bones are free to move. A group of 20 knees receiving medial UKA with dynamically referenced tactile-robotic assistance was studied. Implant placement errors were comparable with those achieved using tactile robotics with rigid stereotactic fixation.

Minimally Invasive Robotic-Arm-Guided Unicompartmental Knee Arthroplasty

Unicompartmental knee arthroplasty is an underused procedure in orthopaedic surgery due to its level of difficulty and the unpredictability of results, which can be related to component malalignment. New robotic arm technology has been developed to assist the surgeon in accurately and reproducibly preparing the femur and the tibia for a minimally invasive bone-sparing unicompartmental knee arthroplasty. This new procedure provides comprehensive three-dimensional planning of unicompartmental knee arthroplasty components, including soft-tissue balancing, followed by accurate resection of the femur and the tibia. This paper reviews this new technology.

Midterm survival of a contemporary modular total knee replacement: A MULTICENTRE STUDY OF 1970 KNEES

This retrospective study evaluated the midterm clinical and radiographic outcomes of a second-generation total knee replacement system. In a multicentre consecutive series of 1512 patients, 1970 knees were treated with the PFC Sigma knee system (Depuy, Warsaw, Indiana). The patients were reviewed for functional outcome, and underwent independent radiographic evaluation at a mean follow-up of 7.3 years (5 to 10). A total of 40 knees (2%) required revision, 17 (0.9%) for infection. The incidence of osteolysis was 2.2%. The ten-year survival with revision for any cause other than infection as the endpoint was 97.2% (95% CI 95.4 to 99.1). The PFC Sigma knee system appears to provide excellent results in the medium term.

Dynamic Soft Tissue Balancing in Total Knee Arthroplasty

Achieving optimal soft tissue balance intraoperatively is a critical element for a successful outcome after total knee arthroplasty. Although advances in navigation have improved the incidence of angular outliers, spatial distance measurements do not quantify soft tissue stability or degrees of ligament tension. Revisions caused by instability, malrotation, and malalignment still constitute up to one-third of early knee revisions. The development of integrated microelectronics and sensors into the knee trials during surgery allows surgeons to evaluate and act on real-time data regarding implant position, rotation, alignment, and soft tissue balance through a full range of motion.

Novel approach for peripheral subcutaneous field stimulation for the treatment of severe, chronic knee joint pain after total knee arthroplasty

Objective:u2002 The objective of this study is to present a novel approach for the treatment of severe, chronic knee joint pain following total knee arthroplasty utilizing peripheral subcutaneous field stimulation and discuss the role of this treatment modality in patients with symptoms that are refractory to conventional pharmacologic, surgical, and physical therapies.

SURVIVORSHIP AND PATIENT SATISFACTION OF ROBOTIC-ASSISTED MEDIAL UNICOMPARTMENTAL KNEE ARTHROPLASTY AT A MINIMUM TWO-YEAR FOLLOW-UP

BACKGROUNDnSuccessful clinical outcomes following unicompartmental knee arthroplasty (UKA) depend on lower limb alignment, soft tissue balance and component positioning, which can be difficult to control using manual instrumentation. Although robotic-assisted surgery more reliably controls these surgical factors, studies assessing outcomes of robotic-assisted UKA are lacking. Therefore, a prospective multicenter study was performed to assess outcomes of robotic-assisted UKA.nnnMETHODSnA total of 1007 consecutive patients (1135 knees) underwent robotic-assisted medial UKA surgery from six surgeons at separate institutions between March 2009 and December 2011. All patients received a fixed-bearing metal-backed onlay implant as tibial component. Each patient was contacted at minimum two-year follow-up and asked a series of five questions to determine survivorship and patient satisfaction. Worst-case scenario analysis was performed whereby all patients were considered as revision when they declined participation in the study.nnnRESULTSnData was collected for 797 patients (909 knees) with average follow-up of 29.6months (range: 22-52months). At 2.5-years of follow-up, 11 knees were reported as revised, which resulted in a survivorship of 98.8%. Thirty-five patients declined participation in the study yielding a worst-case survivorship of 96.0%. Of all patients without revision, 92% was either very satisfied or satisfied with their knee function.nnnCONCLUSIONnIn this multicenter study, robotic-assisted UKA was found to have high survivorship and satisfaction rate at short-term follow-up. Prospective comparison studies with longer follow-up are necessary in order to compare survivorship and satisfaction rates of robotic-assisted UKA to conventional UKA and total knee arthroplasty.

Medical Comorbidities Impact the Episode-of-Care Reimbursements of Total Hip Arthroplasty

BACKGROUNDnTotal hip arthroplasty (THA) costs are a source of great interest in the currently evolving health care market. The initiation of a bundled payment system has led to further research into costs drivers of this commonly performed procedure. One aspect that has not been well studied is the effect of comorbidities on the reimbursements of THA. The purpose of this study was to determine if common medical comorbidities affect these reimbursements.nnnMETHODSnA retrospective, level of evidence III study was performed using the PearlDiver supercomputer to identify patients who underwent primary THA between 2007 and 2015. Patients were stratified by medical comorbidities and compared using the analysis of variance for reimbursements of the day of surgery, and over the 90-day postoperative period.nnnRESULTSnA cohort of 250,343 patients was identified. Greatest reimbursements on the day of surgery were found among patients with a history of cirrhosis, morbid obesity, obesity, chronic kidney disease (CKD) and hepatitis C. Patients with cirrhosis, hepatitis C, chronic obstructive pulmonary disease, atrial fibrillation, and CKD incurred in the greatest reimbursements over the 90-day period after surgery.nnnCONCLUSIONnMedical comorbidities significantly impact reimbursements, and inferentially costs, after THA. The most costly comorbidities at 90 days include cirrhosis, hepatitis C, chronic obstructive pulmonary disease, atrial fibrillation, and CKD.

The Impact of Discharge Disposition on Episode-of-Care Reimbursement After Primary Total Hip Arthroplasty

BACKGROUNDnTotal joint arthroplasty (TJA) accounts for more Medicare expenditure than any other inpatient procedure. The Comprehensive Care for Joint Replacement model was introduced to decrease cost and improve quality in TJA. The largest portion of episode-of-care costs occurs after discharge. This study sought to quantify the cost variation of primary total hip arthroplasty (THA) according to discharge disposition.nnnMETHODSnThe Medicare and Humana claims databases were used to extract charges and reimbursements to compare day-of-surgery and 91-day postoperative costs simulating episode-of-care reimbursements. Of the patients who underwent primary THA, 257,120 were identified (204,912 from Medicare and 52,208 from Humana). Patients were stratified by discharge disposition: home with home health, skilled nursing facility, or inpatient rehabilitation facility.nnnRESULTSnThere is a significant difference in the episode-of-care costs according to discharge disposition, with discharge to an inpatient rehabilitation facility the most costly and discharge to home the least costly.nnnCONCLUSIONnPostdischarge costs represent a sizeable portion of the overall expense in THA, and optimizing patients to allow safe discharge to home may help reduce the cost of THA.

A Targeted Approach to Ligament Balancing Using Kinetic Sensors

BACKGROUNDnCurrently, soft-tissue imbalance contributes to several of the foremost reasons for revision following primary TKA, including instability, stiffness, and aseptic loosening. In order to decrease the incidence of soft-tissue imbalance, intraoperative sensors were developed to provide real-time, quantitative load data within the knee. This study examines the intraoperative data of a group of multicenter patients to determine how targeted ligament releases affect intra-articular loading, and to understand which types of releases are necessary to achieve quantified ligament balance.nnnMETHODSnA group of 129 patients received sensor-assisted TKA, as part of a multicenter study. Medial and lateral loading data were collected pre-release, during any sequential releases, and post-release. All data were collected at 10°, 45°, and 90° during range of motion testing. Ligament release type, release technique type, and resultant loading were collected.nnnRESULTSnLoading across the joint decreased, overall, and became more symmetrical after releases were performed. On average, between 2 and 3 corrections were made (up to 8) in order to achieve ligament balance. The ligament release type and subsequent quantified change in loading were in agreement with historical, qualified sources.nnnCONCLUSIONnObjective data from sensor output may assist surgeons in decreasing loading variability and, thereby, decreasing ligament imbalance and its associated complications.