MARS MRI Characteristics of Adverse Local Tissue Reactions in Taper Corrosion of Metal-On-Polyethylene THA Differ From Metal-On-Metal THA.

BACKGROUND: Metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) has been recommended as a cross-sectional imaging modality in clinical evaluation of adverse local tissue reactions (ALTRs) in metal-on-metal (MoM) patients and metal-on-polyethylene (MoP) patients with taper corrosion. The aim of the study was to compare MARS MRI characteristics of ALTR in MoM total hip arthroplasty (THA) with ALTR in MoP THA with modular taper corrosion. METHODS: A total of 197 patients with ALTR were evaluated: 86 patients with MoM THA; 37 MoP patients with head-neck taper corrosion; and 74 MoP patients with neck-stem dual taper corrosion. MARS MRI scans were evaluated to identify location, size, type of ALTR (I-III), and associated ALTR synovitis (cystic, solid, and mixed). RESULTS: MARS MRI characteristics of ALTR were significantly different between the MoM and MoP groups (P = .017). The MoP group demonstrated the highest proportion of thick-walled cystic masses type II (56.7% in head-neck taper corrosion MoP and 46.5% in dual taper corrosion MoP vs 28.7% in MoM), whereas the MoM group had the highest proportion of thin-walled cystic masses type I. MoM implants (96.8%) were significantly more likely to have ALTR in multiple locations compared with both MoP groups (P = .001). CONCLUSION: This study demonstrates that MARS MRI characteristics of ALTR differ by bearing type with a significantly higher percentage of mixed type and solid type ALTR in the taper corrosion MoP THA compared with MoM THA. This information provides clinically useful information in evaluation of symptomatic MoP and MoM THA patients for ALTRs.

Sensitivity and Specificity of Serum and Synovial Fluid Markers in Diagnosis of Infection in Head-Neck Taper Corrosion of Metal-On-Polyethylene Total Hip Arthroplasty.

BACKGROUND: The accurate diagnosis of periprosthetic joint infection (PJI) in the setting of adverse local tissue reactions in patients with metal-on-polyethylene (MoP) total hip arthroplasty (THA) secondary to head-neck taper junction corrosion is challenging as it frequently has the appearance of purulence. The aim of this study is to evaluate the utility of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and synovial fluid markers in diagnosing PJI in failed MoP THA due to head-neck taper corrosion. METHODS: A total of 89 consecutive patients with MoP THA with head-neck taper corrosion in 2 groups was evaluated: (1) infection group (n = 11) and (2) noninfection group (n = 78). All patients had highly crossed polyethylene with cobalt chromium femoral heads and had preoperative synovial fluid aspiration. In addition, serum cobalt and chromium levels were analyzed. RESULTS: The optimal cutoff value for synovial white blood cell was 2144 with 93% sensitivity and 84% specificity. Neutrophil count optimal cutoff value was 82% with 93% sensitivity and 82% specificity. Receiver operating characteristic analysis of ESR and CRP determined optimal cutoff at 57 mm/h and 35 mg/L with 57% sensitivity and 94% specificity and 93% sensitivity and 76% specificity, respectively. There were no significant differences in metal ion levels between the infected and noninfected groups. CONCLUSION: The results of this study suggest that ESR and CRP are useful in excluding PJI, whereas both synovial white blood cell count and neutrophil percentage in hip aspirate are useful markers for diagnosing infection in MoP THA patients with head-neck taper corrosion associated adverse local tissue reaction.

Revision Total Hip Arthroplasty for Paprosky Type III Acetabular Defect With Structural Allograft and Tantalum Trabecular Metal Acetabular Cup.

There are several surgical options for addressing Paprosky type III acetabular defects during revision total hip arthroplasty. In physiologically young and active patients, using structural bone graft to restore bone defects and provide adequate initial support for the revision acetabular component is one such option. This study reports the mid-term results of using a structural allograft accompanied by a trabecular metal-coated hemispherical cup for Paprosky type III defects. A retrospective analysis was performed of the data collected for 20 consecutive hips in 20 patients (mean age, 56.2 years; range, 43-68 years) with minimum 3-year follow-up (mean, 5.4 years; range, 3.3-10.3 years) who had a structural allograft accompanied by a trabecular metal-coated hemispherical cup for Paprosky type III defects. Only 1 hip had cup migration, which was less than 3 mm in vertical and less than 5° in inclination and recognized as loosening without symptoms. All grafts showed good incorporation with trabecular bridging over the graft and host bone. The mean modified Harris hip score showed significant improvement, from 29.7 (range, 11-52) preoperatively to 84.1 (range, 77-91) at the latest follow-up (P<.05). The use of a structural allograft combined with a tantalum trabecular metal acetabular cup in acetabular revision for Paprosky type III defects had a satisfactory mid-term clinical result. This is a viable option for patients with large acetabular shelf defects. [Orthopedics. 2018; 41(6):e861-e867.].

Metallosis in cemented titanium alloy total knee arthroplasty without apparent metal-on-metal articulation.

BACKGROUND: Metallosis is an uncommon phenomenon observed in late failures of cemented total knee arthroplasty (TKA), and it is rarely seen in the absence of metal-on-metal articulation. METHODS: We report the case of a TKA patient with cemented titanium-alloy components and a polyethylene patella that was revised for early loosening with intra-operative severe metallosis. RESULTS: We found that loosening and severe metallosis were associated with methacrylate particle abrasion on titanium alloy surfaces. CONCLUSION: Serum titanium ion level measurement may be helpful in the workup of a painful TKA with titanium-alloy components in order to establish a diagnosis.

Surgical treatment of displaced pediatric lateral condyle fractures of the humerus by the posterior approach.

The surgical approach for open reduction and internal fixation of lateral condyle fractures in children is controversial. Some authors recommend the lateral approach to the elbow over the posterior approach because of theoretical concern for injury to the vascular supply of the distal humerus and potential avascular necrosis (AVN). The purpose of this retrospective case series study is to report the outcomes of open reduction and internal fixation of displaced lateral condyle fractures of the humerus by the posterior approach. Fifteen consecutive cases were reviewed and the posterior approach resulted in minimal postoperative loss of motion, no angular deformity, cosmetic scars, and no AVN. We support that AVN occurs because of stripping of soft tissues from the lateral condyle fragment and not the approach used. Stripping of soft tissues is not required when using the posterior approach because of excellent visualization of the fracture reduction.

Achieving 90% Adoption of Clinical Practice Guidelines Using the Delphi Consensus Method in a Large Orthopedic Group.

BACKGROUND: Little is known about the implementation rate of clinical practice guidelines (CPGs). Our purpose was to report on the adoption rate of CPGs created and implemented by a large orthopedic group using the Delphi consensus method. METHODS: The draft CPGs were created before the group's annual meeting by 5 teams each assigned a subset of topics. The draft guidelines included a statement and a summary of the available evidence. Each guideline was debated in both small-group and plenary sessions. Voting was anonymous and a 75% supermajority was required for passage. A Likert scale was used to survey the patient's experience with the process at 1 week, and the Kirkpatrick evaluation model was used to gauge the efficacy of the process over a 6-month time frame. RESULTS: Eighty-five orthopedic surgeons attended the meeting. Fifteen guidelines grouped into 5 topics were created. All passed. Eighty-six percent of attendees found the process effective and 84% felt that participating in the process made it more likely that they would adopt the guidelines. At 1 week, an average of 62% of attendees stated they were practicing the guideline as written (range: 35%-72%), and at 6 months, 96% stated they were practicing them (range: 82%-100%). CONCLUSION: We have demonstrated that a modified Delphi method for reaching consensus can be very effective in both creating CPGs and leading to their adoption. Further we have shown that the process is well received by participants and that an inclusionary approach can be highly successful.

Overgrowth after femoral shaft fractures in infants treated with a Pavlik harness.

This study was performed to determine whether overgrowth occurs when treating infantile femoral shaft fractures with a Pavlik harness. Twenty-three patients, aged less than 1 year, treated with a Pavlik harness for a femoral shaft fracture were included. Shortening at the time of injury was recorded on radiographs and compared with those obtained at the follow-up visit 18 months or later. Average overgrowth was 5 mm (1-18 mm). Overgrowth occurs in infants following treatment of femoral fractures with a Pavlik harness. Initial shortening of up to 18 mm was acceptable and resulted in a leg-length discrepancy of less than 5 mm due to overgrowth in our population.