Periprosthetic osteolysis after total hip replacement: molecular pathology and clinical management

Periprosthetic osteolysis is a serious complication of total hip replacement (THR) in the medium to long term. Although often asymptomatic, osteolysis can lead to prosthesis loosening and periprosthetic fracture. These complications cause significant morbidity and require complex revision surgery. Here, we review advances in our understanding of the cell and tissue response to particles produced by wear of the articular and non-articular surfaces of prostheses. We discuss the molecular and cellular regulators of osteoclast formation and bone resorptive activity, a better understanding of which may lead to pharmacological treatments for periprosthetic osteolysis. We describe the development of imaging techniques for the detection and measurement of osteolysis around THR prostheses, which enable improved clinical management of patients, provide a means of evaluating outcomes of non-surgical treatments for periprosthetic osteolysis, and assist in pre-operative planning for revision surgery. Finally, there have been advances in the materials used for bearing surfaces to minimise wear, and we review the literature regarding the performance of these new materials to date.Donald W. Howie, Susan D. Neale, David R. Haynes, Oksana T. Holubowycz, Margaret A. McGee, Lucian B. Solomon, Stuart A. Callary, Gerald J. Atkins, David M. Findla

Radiographic and Navigation Measurements of TKA Limb Alignment Do Not Correlate

Precise pre- and postoperative anatomic measurements are necessary to plan, perform, and evaluate total knee arthroplasty (TKA). We evaluated the relationship between radiographic and navigation alignment measurements, identified sources of error in radiographic and navigated alignment assessment, and determined the differences between desired and clinically accepted alignment. Fifty-eight computer-assisted TKAs were performed and limb alignment measurements were recorded both pre- and postoperatively with standard radiographs and with an intraoperative navigation system. Intraoperative navigation produced consistent navigation-generated alignment results that were within 1° of the desired alignment. The difference between preoperative radiographic and navigation measurements varied by as much as 12° and the difference between postoperative radiographic and navigation measurements varied by as much as 8°. This discrepancy depended on the degree of limb deformity. Postoperative radiographic measurements have inherent limitations. Navigation can generate precise, accurate, and reproducible alignment measurements. This technology can function as an effective tool for assessing pre- and postoperative limb alignment and relating intraoperative alignment measurements to clinical and functional outcomes

Characterization of the Relative Change in Objective and Subjective Metrics by Baselining Patients Who have Wearable Technology Prior to Total Knee Arthroplasty

Wearable sensors and associated supporting technologies (i.e., patient applications) can provide both objective (joint position, step counts, etc.) and subjective data (i.e., pain scores and patient-reported outcome measures) to track a patient's episode of care. Establishing a subjective and objective baseline of a patient's experience may arguably be beneficial for multiple reasons, including setting recovery expectations for the patient and demonstrating the effectiveness or success of the intervention. In this pilot study, we characterized a subset of patients (n = 82 from 7 surgeons) using a wearable sensor system at least 6 days prior to total knee arthroplasty and provided post-surgical data up to 50 days post-intervention. The 5-day average prior to surgery for total step counts (activity), achieved flexion and extension on a progress test (functional limit) and visual analog scale (VAS) daily pain score were calculated. The difference from baseline was then calculated for each patient for each day post-surgery and reported as averages. On average, a patient will experience a relative deficit of 4,000 steps immediately following surgery that will return to near-baseline levels 50 days post-intervention. A 30-degree deficit in flexion and a 10-degree deficit in extension will return at a similar rate as steps. Relative pain scores will worsen with an increase of approximately 3 points immediately following surgery. However, pain will decrease by two points relative to baseline between 40 and 50 days. The results of this pilot study demonstrate a method to baseline a patient's presurgical subjective and objective data and to provide a reference for postsurgical recovery expectations. Applications for this data include benchmarking for evaluating intervention success as well as setting patient expectations

Remote Monitoring using Wearable Technology after Knee Arthroplasty Using a Joint-Specific Wearable Device: A Prospective Cohort Study of 435 patients with 6 week follow up

Introduction As wearable devices become more sophisticated, their application in monitoring the post-surgical recovery curve following Total Knee Arthroplasty (TKA) may be used to assist with rehabilitation and general care. While there is growing interest in this area, much of the research involves studies with small samples, non-pragmatic designs, and short monitoring periods. This study aims to characterize the progress and recovery kinetics of remote monitoring in the early post-TKA period, using many patients and across multiple surgeons and institutions. Methods Between June 2018 and June 2021, adult patients undergoing primary unilateral partial or total Knee Arthroplasty for end-stage knee osteoarthritis were preoperatively recruited to wear a remote monitoring system to track their recovery. Patients were provided with device education and knee specific surface sensors. The data collected by the sensors were transmitted to a smartphone application. Patients wore the surface sensors for a period as defined by their surgeon (2-, 4-, or 6-weeks duration). Primary measures were maximal daily flexion, minimal daily extension, and Total Daily Steps (TDS). Secondary outcomes were patient-reported pain scores. Results A total of 435 patients were recruited into the study. The primary outcomes of flexion and extension did not significantly differ from baseline, and TDS improved significantly from preoperative baseline to 6 weeks postoperative follow up. All metrics improved relative to surgical intervention relative to 6 weeks postoperative. Conclusions This study demonstrates that remote monitoring using knee specific surface sensors can capture the expected recovery kinetics following knee replacement surgery. The data provided, range of motion and total daily step counts can be used by providers to set expectations for recovery following intervention. Further work is required to compare surface sensor monitoring against standard post-surgical outcome measures to evaluate whether superior results may result from remote monitoring

Normative Values for Daily Functional Recovery Patterns following Total Knee Arthroplasty

Wearable devices provide the ability for clinical teams to continuously monitor patients' rehabilitation progress with objective data. Understanding expected recovery patterns following total knee arthroplasty (TKA) enables prompt identification of patients failing to meet these milestones. The aim of this study was to establish normative values for daily functional recovery in the first six weeks after TKA using a wearable device. This prospective study included patients who underwent TKA between 2020 and 2023, treated by 11 surgeons from 8 institutions. Eligible participants were aged 18 or older, had a primary unilateral TKA, and owned a smartphone. Knee range of motion (ROM), total daily steps (TDS), cadence, and device usage were measured continuously over six weeks. Statistical analysis included analysis of variance (ANOVA) using post-hoc Tukey honest significant difference tests (HSD). The cohort of 566 participants had a mean age of 65 and 69 for men and women, respectively (range, 50 to 80). Women comprised 61% (n = 345) of study participants. There were 82% of women and 90% of men who had a body mass index (BMI) > 30. The average daily wear time of the device was 12 hours (± 4) for a total of 45 days (± 27). Recovery was nonlinear, with the greatest gains in the first 3 weeks post-surgery for all metrics. Men demonstrated greater total daily step counts and cadence when compared to women. Obese patients demonstrated poorer performance when compared to lower-BMI patients. To our knowledge, this study presents the first normative data for tracking daily functional recovery in TKA patients using wearable sensors. Standardizing the TKA recovery timeline allows surgeons to isolate factors affecting patients' healing processes, accurately counsel them preoperatively, and intervene more promptly postoperatively when rehabilitation is not within standard recovery parameters

A Stereotactic/Robotic System for Pedicle Screw Placement

. We are developing a robotic system to assist a surgeon in placing spinal pedicle screws. While several groups have undertaken such systems, our approach differs in that it endeavors to remain as close to current clinical technique as possible, yet achieve stereotactic accuracy. This paper describes the conventional surgical methodology, justifies the need for stereotactic/robotic assistance, and discusses the various approaches to system design. In describing our system design, we emphasize key issues that arise with regard to robot accuracy, image linearity, and system registration. 1. Pedicle Screw Placement Surgery 1.1 Conventional Methodology Currently about 60,000 lumbosacral fusions are performed a year in the United States using a variety of different surgical techniques and instrumentation. These various surgical techniques, though different, follow a similar methodology. The patient is in a prone position and the surgical approach is posterior. The vertebral grooves have to..