Aim

This was a multicenter, randomized, clinical trial to compare the 90-day 1) incidence of surgical site complications (SSC); 2) health care utilization (the number of dressing changes, readmission, and reoperation); and 3) the patient-reported outcomes (PRO) in high-risk patients undergoing revision total knee arthroplasty (rTKA) with postoperative closed incision negative pressure wound therapy (ciNPT) versus a standard of care (SOC) silver-impregnated occlusive dressing.

Background

Cementless femoral fixation in total hip arthroplasty (THA) continues to rise worldwide, accompanied by the increasing abandonment of cemented femoral fixation. Cementless fixation is known to contribute to higher rates of post-operative complications and reoperations. New data is available from the Centers for Medicare and Medicaid Services (CMS) regarding total costs of care from the Bundled Payment for Care Improvement (BPCI) and Comprehensive Care for Joint Replacement (CJR) initiatives.

INTRODUCTION

Component impingement in total hip arthroplasty (THA) can cause implant damage or dislocation. Dual mobility (DM) implants are thought to reduce dislocation risk, but impingement on metal acetabular bearings may cause femoral component notching. We studied the prevalence of (and risk factors for) femoral notching with DM across two institutions.

Introduction: Computer-based wear analysis is currently the most accurate method for determining the in vivo wear rates of polyethylene liners during total hip arthroplasty. MRI of a total hip is emerging as the best method for determining the intra-articular volume of particulate debris. The purpose of this study is to determine if there is a correlation between polyethylene wear and the development of particle load in patients with highly crosslinked (HXLP) liners.

Materials and Methods: 20 well-functioning total hips (7 metal heads against HXLP liners and 13 ceramic heads against HXLP liners) in 18 young active individuals were analyzed using the following criteria: femoral head penetration of the liner was measured by Roman (ROntgen Monographic ANalysis) software and particulate load was calculated by MRI criteria as described by Potter et al. Clinical and radiographic analyses were performed using HSS, WOMAC, and criteria defined by DeLee, Charnley, and Engh. The average age of the patients was 57 (Range 45–67) and average follow-up was 1.6 y (range 1.0 – 3.0 y).

Results: All implants appeared well osteointegrated with no radiographic evidence of osteolysis. All patients had well-functioning total hips with a greater than one mile daily walking tolerance. A trend towards correlation was observed between increased polyethylene wear and increased particulate volumes. Average HXLP wear was 0.03 mm (range −0.19 to 0.27 mm) and average particle volume was 841 (range 6951 to 0). One patient in particular recorded 0.27 mm of polyethylene wear, mild particle disease and a particle disease volume of 3321 at 1.6 years follow-up. However, statistical significance could not be achieved with these data points.

Conclusions: There appears to be a relationship between polyethylene wear as measured by computer-based systems and particulate volume as measured by MRI. Limitations of the current methodology include the inability of computer-based systems to detect precise levels of minimal wear with HXLP liners, and the highly sensitive MRI images which may be detecting more than just wear debris.

Proximally-coated non-cemented tapered femoral stems have demonstrated excellent long-term clinical results. However, there is sparse literature reporting the incidence of failure of osteointegration in patients with this stem design. The aim of this study is to report this incidence and identify factors which may increase its risk.

206 elective primary total hip arthroplasties were performed consecutively with a single stem design over a three-year period. All patients were evaluated clinically and radiographically. Radiographic parameters were analyzed for any potential risk factors that may predispose to failure of osteointegration.

Three of 206 hips failed to osteointegrate and subsequently underwent revision surgery, for an incidence of 1.5%. The average time to revision was 1.2 years. The presenting complaint was persistent pain and radiographs revealed a progressive linear lucency at the proximal implant-bone interface in all three patients. Each patient had been implanted with a large-sized stem that had achieved a diaphyseal fit radiographically. This cohort had a statistically lower canal-flare index (p < 0.05) when compared to the rest of the study group. At the time of surgery, all stems were found to be loose and were easily removed.

Failure of osteointegration in this type of stem is an uncommon but serious complication that may necessitate revision surgery. Risk factors predisposing to a failure to osteointegrate are a mismatch between the patient’s proximal femoral geometry and the stem, specifically a large stem in a Dorr type C femur, leading to a diaphyseal rather than a metaphyseal wedge.

Non-cemented tapered wedge femoral stems have gained popularity given their excellent long-term clinical success rates. However, there is sparse literature reporting the incidence of early postoperative periprosthetic femur fractures in patients with this stem design. The aim of this study is to report this incidence and to identify factors which may increase the risk of such fractures.

The charts of all patients who were implanted with a single design of a tapered wedge femoral stem at a single institution were retrospectively reviewed to identify any early periprosthetic femur fractures, defined as occurring within the first year of surgery. Demographic, operative, and radiographic details were analyzed for potential risk factors that may predispose to periprosthetic fractures, and compared to a cohort of patients with the same implant that was matched for age, sex, and pre-operative diagnosis and did not have a periprosthetic fracture.

Six fractures were identified in 2220 stems implanted over a five year period, for an incidence of 0.3%. The average time to fracture was nine weeks post-operatively. Five fractures were Vancouver Type B2, and the other was Vancouver Type A. Three stems were radiographically undersized, and two failed to achieve a proximal wedge fit because of distal fixation. When compared to the matched cohort, there was no statistical significance with regard to body-mass index, morphological cortical index, or canal-bone ratio. However the fracture cohort did have a statistically lower canal-calcar ratio (p < 0.05) and statistically higher canal-flare index (p < 0.05).

Early postoperative periprosthetic femur fracture around a tapered wedge stem is a rare but potentially devastating complication. Risk factors which may predispose to fracture are a proximal-distal mismatch in femoral geometry and an undersized implant.

The ability of optimised MRI to detect periarticular bony and soft tissue pathology in the post-arthroplasty hip is well documented; specifically it is able to detect early stages of particle disease well before osteolysis is apparent on radiographs. This is a prospective study designed to utilise MRI for the detection of early particle disease in asymptomatic patients after total hip arthroplasty.

Patients who underwent routine non-cemented THA were recruited from three different groups: metal-on-polyethylene, ceramic-on-ceramic, and ceramic-on-polyethylene bearing surfaces. All patients enrolled underwent optimised MRI one to three years (mean 1.7) after the index procedure. Images were analyzed for the presence of synovial proliferation, fibrous membrane formation or osteolysis. Particle disease was correlated with type of bearing surface, pain, activity level, patient satisfaction, and clinical outcome scales.

Thirty-two hips have been enrolled in the study to date. Early particle disease was seen in two of seven metal-on-polyethylene hips (29%), four of twelve ceramic-on-ceramic hips (33%), and six of thirteen ceramic-on-polyethylene hips (46%). Focal osteolysis was seen in one patient with a ceramic-on-polyethylene hip. These values were not statistically significant among the groups. The presence of early particle disease did not correlate with pain, activity level, patient satisfaction, or other clinical outcome scales.

This study allows patients with a well functioning total hip arthroplasty to be prospectively followed with MRI. It is the first to document the natural history of particle disease in vivo and considerably enhances our knowledge of periarticular pathology in the post-operative hip. These results demonstrate early particle disease is relatively common yet asymptomatic; they do not demonstrate advantages of any bearing couple over another for protection against particle disease at short-term follow-up.

We previously reported no clinical differences in short-term results in 26 patients that underwent fixed-bearing (FB) total knee arthroplasty in one knee followed by a rotating-platform (RP) version of the same implant in the contralateral knee at a later date. This study presents intermediate-term results in this unique cohort and uses optimised MRI for detection of particle disease in both knees.

Patients from the original series were asked to complete questionnaires regarding both knees. In addition, both knees were evaluated with optimised MRI, which has been shown to be useful in evaluating early particle disease and osteolysis before its appearance on radiographs.

Nine patients have been enrolled to date. At an average follow-up of 8.3 years for the FB side and 6.5 years for the RP side, no significant differences were found with respect to knee preference, pain, or overall satisfaction. Seven patients underwent MRI studies of both knees. Two FB knees demonstrated a massive intracapsular burden of particle disease (average 3066 mm3) with reactive synovitis, compared to no obvious particle disease in any RP knees. Osteolysis was seen around the femur in one FB knee and around the patella in two FB knees, compared to only around a single patella in the RP side.

RP knees continue to demonstrate excellent patient satisfaction that is comparable to clinical results of the FB design; however, FB knees demonstrate higher rates of particle disease and early osteolysis on MRI. This is the first study to demonstrate in vivo advantages of RP over FB designs. It is unclear whether this is due to the slightly longer follow-up period for the FB knees or a decreased wear rate in the RP design; these differences may become apparent with longitudinal follow-up.