What is the optimal protocol to decontaminate a dropped custom polyethylene component?

BACKGROUND: With advancements in manufacturing technology, custom orthopedic implants have become commercially available. A new concern with these implants is what to do when custom heat-sensitive components are contaminated. While intraoperative decontamination protocols for dropped autograft tissue have been described, no literature describes an intraoperative protocol for decontaminating one-of-a-kind polyethylene implants. The purpose of this work is to describe and evaluate polyethylene decontamination protocols using materials found in the average operating suite that could be used intraoperatively. METHODS: Sixteen custom polyethylene inserts were contaminated with potting soil and processed in one of four protocols: 1) hydrogen peroxide, 2) chlorhexidine gluconate, 3) povidone-iodine, or 4) control. Following processing, the implants were cultured with swabs or sonication. Each implant was evaluated with one aerobic, one anaerobic, and one fungal culture. RESULTS: All cultures from implants processed with both the chlorhexidine and povidone-iodine protocols were negative. One colony of Ralstonia species was isolated on the aerobic culture from one of the implants processed with hydrogen peroxide. The remainder of the cultures from implants processed with the hydrogen peroxide protocol were negative. All of the cultures for each culture modality from all of the control implants were positive with florid proliferation. CONCLUSION: In the rare situation that a custom polyethylene insert becomes contaminated intraoperatively, the surgeon should consider all salvage options. Chlorhexidine and povidone-iodine decontamination protocols eliminated bacterial growth following culture swabs or sonicate taken from the contaminated polyethylene inserts while hydrogen peroxide failed in one case to completely eradicate growth.

Preoperative Anemia Is Associated With Failure of Open Debridement Polyethylene Exchange in Acute and Acute Hematogenous Prosthetic Joint Infection.

BACKGROUND: Acute and acute hematogenous prosthetic joint infections (PJIs) are often treated with open debridement and polyethylene exchange (ODPE) in an effort to save the prosthesis, decrease morbidity, and reduce costs. However, failure of ODPE may compromise a subsequent 2-stage treatment. The purpose of this study is to identify patient factors that impact the success of ODPE for acute and acute hematogenous PJIs. METHODS: A retrospective review examined comorbidities, preoperative laboratory values, and patient history for patients with successful and failed ODPE treatment for acute perioperative or acute hematogenous periprosthetic hip or knee joint infections. Successful treatment was defined as retaining a well-fixed implant without the need for additional surgery for a minimum of 6-month follow-up with or without lifelong oral maintenance antibiotics. RESULTS: Fifty-three of 72 patients (73.6%) underwent successful ODPE. Of the 19 failures, 14 completed 2-stage revision with one subsequent known failure for recurrent infection. Patients with a Staphylococcus aureus infection were more likely to fail ODPE (48.3% vs 11.6%, P = .0012, odds ratio 7.1, 95% confidence interval 2.3-25.3). Patients with a preoperative hematocrit ≤32.1 were also more likely to fail ODPE (55% vs 16%, P = .0013, odds ratio 6.7, 95% confidence interval 2.2-22.4). When neither risk factor was present, 97.1% of PJIs were successfully treated with ODPE. CONCLUSION: S aureus infection and preoperative hematocrit ≤32.1 are independent risk factors for ODPE failure. ODPE is a safe alternative to 2-stage revision in patients without preoperative anemia and without S aureus infection. Two-thirds of patients with a failed ODPE were successfully treated with a 2-stage reimplantation.

Saucerization Versus Complete Resection of a Symptomatic Discoid Lateral Meniscus at Short- and Long-term Follow-up: A Systematic Review.

PURPOSE: To evaluate the surgical outcomes of symptomatic discoid menisci after total meniscectomy, saucerization, and suture repair of tears of a discoid meniscus at short- and long-term follow-up. METHODS: A systematic review was conducted using the Pubmed and ScienceDirect databases in adherence with Preferred Reporting Items of Systematic Reviews and Meta-Analysis guidelines. Short- and long-term follow-up were defined as an average follow-up of <4 years and >4 years, respectively. Pooled quantitative synthesis was performed on studies that reported results of total meniscectomy and saucerization in the same study. A systematic review was performed on studies that reported data on saucerization, total meniscectomy, and/or repair. RESULTS: A total of 19 studies for the short term and 22 for the long term were identified that met inclusion criteria for qualitative review. Of these, 4 short-term and 5 long-term studies were included in the quantitative synthesis. No significant differences in Ikeuchi scores are seen in the short-term studies between saucerization and total meniscectomy; however, the long-term studies did find a statistical difference favoring saucerization (P < .001). The differences noted between the preoperative and postoperative Lysholm scores in the short term were 24.1 (95% conflict of interest: 10.25-37.95) in 3 studies and 22.38 (95% conflict of interest: 17.68-27.07) in the 4 long-term studies for saucerization. Suture repair with saucerization versus saucerization without suture repair revealed a statistical difference in only 1 of 5 studies. CONCLUSIONS: Long-term data demonstrate significantly improved patient reported outcomes in favor of saucerization over total meniscectomy. Suture repair of tears of a lateral discoid meniscus does not demonstrate improved outcomes over partial meniscectomy without repair. Considering the cost of repair and lack of demonstrated improvement, based on the limited available data, we do not recommend repair of the abnormal anatomy in a torn lateral discoid meniscus. LEVEL OF EVIDENCE: Level IV, systematic review.

In-Toeing Is Often a Primary Care Orthopedic Condition.

OBJECTIVE: To evaluate in-toeing consults to a pediatric orthopedic clinic to determine the proportion that could be managed by a primary care physician. STUDY DESIGN: A prospective registry was created for 143 consecutive children referred to a pediatric orthopedic clinic for "in-toeing." Each patient underwent a careful history and physical examination, which included a rotational profile. We recorded the final diagnosis, treatment offered, follow-up visit results, and the source of the referral. RESULTS: After pediatric orthopedic evaluation, 85% of patients had a confirmed diagnosis of in-toeing, and 15% had a different final diagnosis. Seventy-four percent of patients had 1 consultation visit, 18% had 2, and 8% had >2 visits. None of the referred patients was a candidate for treatment by casting or surgery. CONCLUSION: In most cases, in-toeing is a normal variation of development that can be managed by counseling and observation by the primary care physician alone. Rare cases of severe in-toeing >2 standard deviations from the mean should likely still prompt referral to a pediatric orthopedic surgeon for potential intervention.

Knee cartilage defect: marrow stimulating techniques.

Painful chondral defects of the knee are very difficult problems. The incidence of these lesions in the general population is not known since there is likely a high rate of asymptomatic lesions. The rate of lesions found during arthroscopic exam is highly variable, with reports ranging from 11 to 72 % Aroen (Aroen Am J Sports Med 32: 211-5, 2004); Curl(Arthroscopy13: 456-60, 1997); Figueroa(Arthroscopy 23(3):312-5, 2007;); Hjelle(Arthroscopy 18: 730-4, 2002). Examples of current attempts at cartilage restoration include marrow stimulating techniques, ostochondral autografts, osteochondral allografts, and autologous chondrocyte transplantation. Current research in marrow stimulating techniques has been focused on enhancing and guiding the biology of microfracture and other traditional techniques. Modern advances in stem cell biology and biotechnology have provided many avenues for exploration. The purpose of this work is to review current techniques in marrow stimulating techniques as it relates to chondral damage of the knee.

Does surgical approach in total hip arthroplasty affect rehabilitation, discharge disposition, and readmission rate?

There is a substantial preoccupation with different surgical approaches and minimally invasive techniques that may improve clinical outcomes for patients who undergo total hip arthroplasty. This study assessed the impact on hospital-related outcomes of the direct anterior approach (DAA) compared with the posterior approach (PA) performed by a single surgeon in 100 consecutive patients in each cohort. Patient age was similar in the DAA (61 ± 1.1 years) compared with the PA (62 ± 1.3, p = 0.733); however, BMI tended to be lower in DAA patients (29.1 ± 0.8) compared with PA patients (31.3 ± 0.7, p = 0.057). The DAA compared with the PA was associated with significantly less blood loss (285 ± 15 vs. 367 ± 21ml, p = 0.002) and transfusions (18 vs. 39 units, p = 0.009), less narcotic usage on postoperative days 1-3 (101 ± 12 vs. 146 ± 12 morphine equivalent dose, p = 0.010), a quicker hospital discharge (70 ± 3.3 vs. 97 ± 5.5 hours, p < 0.001), and a more favorable disposition (97% vs. 84% discharged home, p = 0.003). Thirty-day readmission rate was significantly higher with the PA (9%) compared with the DAA (1%, p = 0.030). The number of cups in the safe zone (5° to 25° anteversion and 30° to 50° inclination) was significantly higher with the DAA (92%) compared with the PA (75%, p = 0.002), possibly attributed to fluoroscopy used with the DAA. The DAA muscle-preservation technique may have led to the benefits observed in this study compared with the muscle-splitting technique associated with the PA.

New insights into BAR domain-induced membrane remodeling.

Mesoscopic simulations and electron microscopy of N-BAR domain-induced liposome remodeling are used to characterize the process of liposome tubulation and vesiculation. The overall process of membrane remodeling is found to involve complex couplings among the N-BAR protein density, the degree of N-BAR oligomerization, and the membrane density. A comparison of complex remodeled liposome structures from mesoscopic simulations with those measured by electron microscopy experiments suggests that the process of membrane remodeling can be described via an appropriate mesoscopic free energy framework. Liposome remodeling more representative of F-BAR domains is also presented within the mesoscopic simulation framework.

Factors influencing local membrane curvature induction by N-BAR domains as revealed by molecular dynamics simulations.

N-BAR domains are protein modules that bind to and induce curvature in membranes via a charged concave surface and N-terminal amphipathic helices. Recently, molecular dynamics simulations have demonstrated that the N-BAR domain can induce a strong local curvature that matches the curvature of the BAR domain surface facing the bilayer. Here we present further molecular dynamics simulations that examine in greater detail the roles of the concave surface and amphipathic helices in driving local membrane curvature. We find that the strong curvature induction observed in our previous simulations requires the stable presentation of the charged concave surface to the membrane and is not driven by the membrane-embedded amphipathic helices. Nevertheless, without these amphipathic helices embedded in the membrane, the N-BAR domain does not maintain a close association with the bilayer, and fails to drive membrane curvature. Increasing the membrane negative charge through the addition of PIP(2) facilitates closer association with the membrane in the absence of embedded helices. At sufficiently high concentrations, amphipathic helices embedded in the membrane drive membrane curvature independently of the BAR domain.