Evaluation of the Painful Total Knee Arthroplasty.

Total knee arthroplasty (TKA) has been associated with notable improvements in health-related quality of life of patients with end-stage knee arthritis. Although most patients experience substantial symptomatic relief after TKA, up to 19% of patients are unsatisfied with their outcome. With the dramatic, projected increase in the number of TKAs performed annually, it is crucial to appreciate the various modes of failure associated with this procedure. A comprehensive understanding of the symptomatology and thorough clinical examination aid in identifying the etiology of ongoing knee pain. Ancillary testing including conventional laboratory analyses, imaging studies, and diagnostic injections supplement a thorough history and physical examination. In addition, novel laboratory markers, RNA/DNA-based tests, and novel imaging modalities are emerging as beneficial tools in evaluating patients with a painful TKA. A well-structured, algorithmic approach in the management of these patients is essential in correctly diagnosing the patient and optimizing clinical outcomes.

Does Taper Design Affect Taper Fretting Corrosion in Ceramic-on-Polyethylene Total Hip Arthroplasty? A Retrieval Analysis.

BACKGROUND: Ceramic-on-polyethylene (CoP) implants have exhibited lower fretting and corrosion scores than metal-on-polyethylene implants. This study aims at investigating the effect of taper design on taper corrosion and fretting in modular CoP total hip arthroplasty (THA) systems. METHODS: Under an institutional review board--approved protocol, a query of an implant retrieval library from 2002 to 2017 identified 120 retrieved CoP THA systems with zirconia toughened alumina femoral heads. Femoral stem trunnions were visually evaluated and graded for fretting, corrosion, and damage at the taper interface. Medical records were reviewed for patient demographics and implant characteristics. Data were statistically analyzed using Spearman correlation and rank-sum tests with a Dunn's post hoc test, with a significance level of α = 0.05. RESULTS: Four different taper designs were evaluated: 11/13 (n = 18), 12/14 (n = 53), 16/18 (n = 21), and V40 (n = 28). There were no statistically significant demographic differences between taper groups for duration of implantation, laterality, patient age, and patient sex, but patients with 16/18 tapers had a higher body mass index than V40 tapers (P = .012). Duration of implantation had a weak positive correlation with both trunnion fretting (ρ = 0.224, P = .016) and corrosion (ρ = 0.253, P = .006). Summed fretting and corrosion scores were significantly greater on the V40 and 16/18 tapers compared with the 12/14 tapers (all P ≤ .001). CONCLUSION: Taper fretting and corrosion were observed in CoP THA implants and were greatest with V40 and 16/18 tapers and lowest with 12/14 tapers. Differences in taper design characteristics may lead to greater micromotion at the taper-head interface, leading to increased fretting and corrosion.

Intramuscular hemangioma after total hip arthroplasty: an iatrogenic etiology.

Soft-tissue hemangioma is a common benign tumor that can develop cutaneously, subcutaneously, or intramuscularly. Hemangioma formation within a muscular compartment is most often developmental in etiology; however, some cases are known to occur after blunt trauma to the soft tissues. To our knowledge, no cases of hemangioma formation after joint arthroplasty have been reported. We present a case of intramuscular hemangioma development within the hip abductor musculature after total hip arthroplasty via an anterolateral approach. Aside from developing congenitally or posttraumatically, hemangiomas may form after surgical dissection and must be considered as a source of anomalous swelling after surgery.

The Role of Aspirin and Unfractionated Heparin Combination Therapy Immediately After Total Hip and Knee Arthroplasty.

Aspirin and unfractionated heparin (UH) are accepted options for venous thromboembolism (VTE) prophylaxis after total joint arthroplasty (TJA). The use of aspirin in addition to UH in preventing VTE after TJA has yet to be studied. The primary objective of this study was to determine VTE rates in patients receiving aspirin monotherapy and those receiving aspirin and UH combination therapy immediately following TJA. A TJA database from a single hospital system was retrospectively reviewed to identify all patients who underwent primary hip or knee arthroplasty from 2013 to 2016. Patients were divided into 3 groups based on postoperative VTE chemoprophylaxis: aspirin only, aspirin with 1 dose of UH, and aspirin with multiple doses of UH. There were 5350 patients included: 1024 aspirin only, 1695 aspirin plus 1 dose of UH, and 2631 aspirin plus multiple doses of UH. Deep venous thrombosis and pulmonary embolus rates did not vary significantly between groups (deep venous thrombosis: 1.1%, 0.9%, and 1.2%, respectively, P=.701; pulmonary embolus: 0.3%, 0.3%, and 0.2%, respectively, P=.894). Transfusion rates were significantly greater with 1 dose of UH (1.8%) and multiple doses of UH (4.3%) compared with aspirin only (0.9%) (P<.001). Additionally, the postoperative hemoglobin decreased significantly more postoperatively with the use of UH (P<.001). Aspirin and UH combination therapy did not decrease VTE incidence compared with aspirin monotherapy. Additionally, there was greater perioperative blood loss and an increased rate of blood transfusion in patients receiving UH. On the basis of these findings, the authors do not recommend UH as an additional mode of VTE prophylaxis when prescribing aspirin after elective TJA. [Orthopedics. 2018; 41(3):171-176.].

Multidrug-Resistant Organisms in the Setting of Periprosthetic Joint Infection-Diagnosis, Prevention, and Treatment.

BACKGROUND: Periprosthetic joint infection (PJI) is a rare yet challenging problem in total hip and knee arthroplasties. The management of PJI remains difficult primarily due to the evolution of resistance by the infecting organisms. METHODS: This review profiles acquired mechanisms of bacterial resistance and summarizes established and emerging techniques in PJI diagnosis, prevention, and treatment. RESULTS: New techniques in PJI diagnosis and prevention continue to be explored. Antibiotics combined with 1 or 2-stage revision are associated with the higher success rates and remain the mainstay of treatment. CONCLUSION: With higher prevalence of antibiotic-resistant organisms, novel antibiotic implant and wound care materials, improved methods for organism identification, and well-defined organism-specific treatment algorithms are needed to optimize outcomes of PJI.

Cost Analysis, Complications, and Discharge Disposition Associated With Simultaneous vs Staged Bilateral Total Knee Arthroplasty.

BACKGROUND: Simultaneous vs staged bilateral total knee arthroplasty (BTKA) has long been debated. The primary objective of this study was to compare actual hospital costs and complication rates in patients undergoing simultaneous BTKA (simBTKA) and staged BTKA (staBTKA) at a single institution. METHODS: A total joint arthroplasty database from a single hospital was used to identify all patients who underwent primary BTKA from 2013 to 2016 and divided into simultaneous and staged groups. StaBTKA patients were included if both procedures were performed within 1 year by the same surgeon. The combined total hospital cost of both procedures was used, and inpatient rehabilitation (IPR) costs were added for all patients discharged to IPR. RESULTS: There were 225 simBTKA and 337 staBTKA patients. SimBTKA patients were younger (61 ± 8 vs 66 ± 8 years, P < .001), had lower body mass index (31.3 ± 5.9 vs 34.0 ± 7.2, P < .001), were more predominately male (48% vs 38%, P = .029), and more likely to require IPR as compared with staBTKA patients. There was no difference in total hospital cost for simBTKA as compared with staBTKA ($24,596 ± $5652 vs $24,915 ± $5756, P = .586). Complications were more prevalent in the simBTKA group, including venous thromboembolism (5.4% vs 1.4%, P = .006) and blood transfusions (15.8% vs 6.2%, P < .001). CONCLUSION: There were higher complication rates with no significant cost savings in actual hospital costs associated with simBTKA, when accounting for the cost of IPR, as compared with staBTKA. The total cost analysis of simBTKA vs staBTKA, using actual cost data, merits further evaluation.