Primary Cement Debris After Total Knee Arthroplasty

Polyethylene wear is accelerated by third body cement debris and contributes to aseptic loosening after knee arthroplasty. Saline irrigation with pulse lavage is expected to render the joint free of such particles. The purpose of this study is to qualitatively characterize such primary cement debris remaining in the knee joint after cemented total knee arthroplasty and briefly discuss ways to decrease it further.

352 Did the Discontinuation of Pulse-Lavage Have A Detrimental Effect on The Quality of Hip Hemiarthroplasties Performed During the First COVID-19 Wave?

Introduction The standard of practice for performing hip hemiarthroplasty is to thoroughly wash and dry the femur with pulse-lavage. With the COVID-19 pandemic we were issued with guidance to minimise Aerosol Generating Procedures (AGPs) and discontinued the use of pulse lavage. Instead, we used a bladder syringe to wash the femoral canal. Method We retrospectively assessed 100 post-operative radiographs following hemiarthroplasties for neck of femur fractures. We used the Barrack classification to assess the bone cement mantle which is an indicator of aseptic loosening. We assessed 50 radiographs pre-covid (using pulse lavage) and 50 radiographs during covid (without pulse lavage). Results Pre-COVID-19, 30% of hemiarthroplasties were deemed as being ‘at risk’. During COVID-19, 64% of hips were deemed as being ‘at risk’. This represents an absolute increase of 34%. Conclusions This forced service change had a detrimental effect on the quality of the bone cement mantle following hip hemiarthroplasty. We recommend following these patients up at 2 years to assess for signs of aseptic loosening. In future pandemics, we recommend carefully weighing up the dangers of using AGPs against the detriment in patient outcomes likely to be experienced.

Direct-Contact Low-Frequency Ultrasound and Pulse Lavage Eradicates Biofilms on Implant Materials In Vitro

Pulse lavage (PL) debridement and ultrasound are both known to be the treatment of biofilm-related periprosthetic joint infection (PJI). However, the efficacy of these in combination is unknown in eradicating biofilm from the orthopaedic metal implant surface. This study was conducted to understand the efficacy of PL and ultrasound in combination in eradicating bacterial biofilms on titanium alloy in vitro. Biofilms of Staphylococcus aureus strains were grown on titanium alloy coupons for 24 h. Then, the coupons were taken to each treatment group: (i) debrided with PL, (ii) exposed to ultrasound, or (iii) exposed to both. An untreated biofilm was set as a control group. Viable plate count and confocal microscopy using live/dead staining was used to measure the amount of biofilm. Viable plate count showed an approximate two-log reduction in CFU/cm2 in PL alone, from an initial cell count on the mental surface of approximately 109 CFU/cm2. The ultrasound caused an approximate seven-log reduction, and the combination group eradicated viable biofilm bacteria completely. Confocal imaging corroborated the CFU data. Our results indicate that PL and ultrasound both are remarkably in eradicating biofilm, and the combination of PL and ultrasound is more effective than alone in reducing biofilm.

The effect of pulsed lavage irrigation on suture knot security

Purpose: The purpose of this study was to determine the effect of low-pressure and pulsed lavage irrigation on suture knot security. Methods: Ninety-tied suture loops were measured for baseline circumference and then subjected to no irrigation, bulb syringe irrigation, or pulsed lavage irrigation. The sutures were placed under a load and then measured for final circumference. A larger circumference difference indicated poorer knot security. Results: There was a statistically significant difference in the knot security between all three groups ( p < 0.001). Pulsed lavage resulted in the greatest circumference increase (0.52 ± 0.19 mm), followed by bulb syringe (0.24 ± 0.18 mm), and lastly no irrigation (0.08 ± 0.00 mm). None of the groups had any catastrophic failures. No knots met the predetermined criteria for knot failure. Conclusion: Pulsed lavage irrigation resulted in a statistically significant decrease in suture knot security as compared to bulb syringe irrigation and no irrigation. None of the groups met the currently accepted criteria for clinical suture failure, which has a relatively arbitrary value. While the available literature does not discuss increases in loop circumference for specific orthopedic applications, this small difference suggests that pulse lavage is unlikely to have a clinically significant impact on the suture integrity for most orthopedic procedures.

Pulse Lavage Fails to Significantly Reduce Bone Marrow Content in Osteochondral Allografts: A Histological and DNA Quantification Study

Background: Current clinical practice calls for pulse lavage of fresh osteochondral allografts (OCAs) to reduce immunogenicity; however, there is limited evidence of its effectiveness in reducing allogenic bone marrow elements. Purpose: To evaluate the effectiveness of pulse lavage in removing marrow elements from trabecular bone in fresh OCA transplantation. Study Design: Controlled laboratory study. Methods: The authors evaluated 48 fresh OCA plugs with 4 different common sizes (14- and 24-mm diameter, 6- and 10-mm thickness). Within each size group, half of the samples underwent pulse lavage (n = 6) with saline solution and half were left untreated (no lavage; control group, n = 6). For each treatment and size group, 3 samples were analyzed for DNA content as an indicator of the number of residual nucleated cells; the other 3 samples were histologically analyzed to assess the presence and distribution of cells within subchondral bone pores in 3 specific locations within the plug: peripheral, intermediate, and core. Results: Osteochondral plugs treated with pulse lavage did not show a significant decrease in DNA content in comparison with untreated plugs. Overall, histological analysis did not show a significant difference between the treated and untreated groups ( P = .23). Subgroup analysis by size demonstrated decreased marrow content in treated versus untreated groups in the thinner plug sizes (14 × 6 mm and 24 × 6 mm). Histological evaluation by zone demonstrated a significant difference between groups only in the peripheral zone ( P = .04). Conclusion: Pulse lavage has limited effectiveness in removing marrow elements, in particular in plugs that are larger in diameter and, more importantly, in thickness. Better techniques for subchondral bone treatment are required for more thorough removal of potentially immunogenic marrow elements. Clinical Relevance: OCA transplantation has become an established treatment modality. Unfortunately, OCA is not without limitations, chiefly its mode of failure through inadequate integration of the allograft subchondral bone with subsequent collapse. In an effort to improve integration, current clinical practice calls for pulse lavage to remove allogenic bone marrow from the subchondral bone in hopes of decreasing the immunogenicity of the graft and facilitating revascularization.