Venous Hemodynamics After Total Hip Arthroplasty: A Comparison Between Portable vs Stationary Pneumatic Compression Devices and the Effect of Body Position.

BACKGROUND: Improvements in device design have allowed for portable pneumatic compression devices (PPCDs). However, portability results in smaller pumps that move less blood. Additionally, although patients often stand when wearing PPCDs, few studies have evaluated the hemodynamic effects of PCDs while standing. METHODS: A crossover study was performed to compare a PPCD (ActiveCare+S.F.T.; Medical Compression Systems, Or Akiva, Israel) to a stationary pneumatic compression device (SPCD) (VenaFlow; DJO Global, Carlsbad, CA) on hemodynamics in supine and standing positions among 2 cohorts composed of 10 controls and 10 total hip arthroplasty patients. Differences in baseline peak venous velocity (PVV), PVV with each PCD, and delta PVV with each PCD were assessed. A multivariate analysis was performed to examine differences between cohorts, devices, and position. RESULTS: In both positions, the SPCD demonstrated a larger change in PVV when compared to the PPCD (P < .001). The total hip arthroplasty group had a greater delta PVV while standing when considering both PCDs together (P < .001). When considering both cohorts, delta PVV was greater while standing, only when the SPCD was used (P < .001). There was no difference between standing and supine positions when the PPCD was used. CONCLUSION: The SPCD demonstrated a greater capacity to increase PPV in the supine and standing positions. The SPCD generated greater values of PVV and delta PVV in the standing position. Although these results demonstrate a difference between devices, it is important to establish the PVV necessary to prevent VTE before one is considered more effective.

What Are Normal Metal Ion Levels After Total Hip Arthroplasty? A Serologic Analysis of Four Bearing Surfaces.

BACKGROUND: The recent experiences with adverse local tissue reactions have highlighted the need to establish what are normal serum levels of cobalt (Co), chromium (Cr), and titanium (Ti) after hip arthroplasty. METHODS: Serum Co, Cr, and Ti levels were measured in 80 nonconsecutive patients with well-functioning unilateral total hip arthroplasty and compared among 4 bearing surfaces: ceramic-on-ceramic (CoC); ceramic-on-polyethylene (CoP); metal-on-polyethylene (MoP), and dual mobility (DM). The preoperative and most recent University of California, Los Angeles (UCLA) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were compared among the different bearing surfaces. RESULTS: No significant difference was found among serum Co and Cr levels between the 4 bearing surface groups (P = .0609 and P = .1577). Secondary analysis comparing metal and ceramic femoral heads demonstrated that the metal group (MoP, modular dual mobility (Stryker Orthopedics, Mahwah, NJ) [metal]) had significant higher serum Co levels compared with the ceramic group (CoC, CoP, MDM [ceramic]) (1.05 mg/L ± 1.25 vs 0.59 mg/L ± 0.24; P = .0411). Spearman coefficient identified no correlation between metal ion levels and patient-reported outcome scores. CONCLUSION: No serum metal ion level differences were found among well-functioning total hip arthroplasty with modern bearing couples. Significantly higher serum Co levels were seen when comparing metal vs ceramic femoral heads in this study and warrants further investigation. Metal ion levels did not correlate with patient-reported outcome measures.

Magnetic Resonance Imaging Predicts Adverse Local Tissue Reaction Histologic Severity in Modular Neck Total Hip Arthroplasty.

BACKGROUND: The association between advanced imaging, serum metal ion levels, and histologic adverse local tissue reaction (ALTR) severity has not been previously reported for Rejuvenate modular neck femoral stems. METHODS: A cohort of 90 patients with 98 Rejuvenate modular neck femoral stems was revised by a single surgeon from July 2011 to December 2014. Before revision, patients underwent multiacquisition variable resonance image combination sequence magnetic resonance imaging (MRI), and serum cobalt and chromium ion levels were measured. Histologic samples from the revision surgery were scored for synovial lining, inflammatory infiltrate, and tissue organization as proposed by Campbell. Regression based on the generalized estimating equations approach was used to assess the univariate association between each MRI, demographic, and metal ion measure and ALTR severity while accounting for the correlation between bilateral hips. Random forest analysis was then used to determine the relative importance of MRI characteristics, demographics, and metal ion levels in predicting ALTR severity. RESULTS: Synovial thickness as measured on MRI was found to be the strongest predictor of ALTR histologic severity in a recalled modular neck femoral stem. CONCLUSION: MRI can accurately describe ALTR in modular femoral neck total hip arthroplasty. MRI characteristics, particularly maximal synovial thickness and synovitis volume, predicted histologic severity. Serum metal ion levels do not correlate with histologic severity in Rejuvenate modular neck total hip arthroplasty.

Short-Term Outcomes and Complications After Rejuvenate Modular Total Hip Arthroplasty Revision.

BACKGROUND: The early short-term outcomes and complications after revision of the recalled Rejuvenate modular neck hip arthroplasty have not been previously reported. This study's purpose is to describe the early outcomes and complications after revision of the Rejuvenate modular femoral neck. METHODS: A retrospective cohort included 92 patients with 92 Rejuvenate modular neck total hip arthroplasty (THA) who underwent revision surgery between July 2011 and April 2014. Preoperative, 1-year, and 2-year patient-reported outcome measures including Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Short Form 12 (SF-12) were described in 92 patients. RESULTS: Complications arose in (12 of 92) 13% of patients including 8 greater trochanteric fractures, 1 intraoperative periprosthetic acetabular fracture, 2 dislocations, 1 early aseptic loosening, and 1 infection requiring a 2-stage revision. Overall, 66% of patients with a complication required reoperation. Significant changes were noted between preoperative and 1- and 2-year outcomes with respect to WOMAC pain score (P = .0031), WOMAC total score (P = .021), SF-12 mental component score (P < .0001), and physical component score (P < .0001). CONCLUSIONS: Patients can expect an improvement in pain (WOMAC pain) and function (total WOMAC, SF-12 Physical Health Composite Scale), but overall worsening in the SF-12 mental component scores. Patients' physical function improvements are offset by worsened mental function scores. Patients undergoing revision of Rejuvenate modular neck THA implants should be counseled on modest functional improvements and relative frequency of complications.