A Hemoglobinopathy That Produces an Array of Different Hemoglobin A1c Values.

Hemoglobin A1c (HbA1c) refers to non-enzymatically glycated hemoglobin and reflects the patient's glycemic status over approximately 3 months. An elevated HbA1c over 6.5% National Glycohemoglobin Standardization Program (NGSP) (48 mmol/mol the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC)) can be used to diagnose diabetes mellitus. In our laboratory, HbA1c is determined by ion-exchange chromatography which has the advantage of detecting common Hb variants such as Hb S, C, E and D without adversely affecting the HbA1c determination. Certain homozygous or compound heterozygous hemoglobinopathies such as homozygous sickle disease and Hb SC disease can significantly lower the HbA1c by reducing red cell lifespan. Occasionally however, rare and mostly benign hemoglobinopathies can interfere with this technique resulting in an apparent elevation of HbA1c in an otherwise non-diabetic patient. In this report, we describe such a hemoglobinopathy termed Hb Wayne that resulted in a significant HbA1c elevation in a normoglycemic individual. HbA1c was determined by multiple methods including immunoassay, a modified capillary electrophoresis and an alternative ion-exchange system. These techniques yielded significantly lower A1c results, more in keeping with the patient's clinical background. The alternative ion-exchange system resulted in a low A1c that was qualified by warning flags on the chromatogram that indicated the result was not reportable. The hemoglobinopathy in question, Hb Wayne, is a frameshift mutation in the alpha globin gene that results in an extended alpha globin polypeptide that can form two variants Hb Wayne I and Wayne II. Hb Wayne is a clinically silent asymptomatic disorder with no hematologic consequences. The artifactual elevation of HbA1c is, in contrast, very significant because it may result in a misdiagnosis of diabetes mellitus leading to unnecessary treatment. In this report, we compare our findings with other descriptions of Hb Wayne in the literature and corroborate a number of previous observations and conclusions.

Revision Dual Mobility Constructs With Unmatched Acetabular and Femoral Components Do Not Increase Failure Rate.

BACKGROUND: Dual mobility (DM) constructs for revision total hip arthroplasty (THA) have continued to grow in popularity to mitigate instability. This benefit comes at the cost of potential unique modes of failure, and there are theoretical concerns that combining femoral and acetabular components from different manufacturers could lead to increased failure rates. We aimed to investigate rates of reoperation between matched and unmatched DM implants used in revision THA. METHODS: We retrospectively reviewed 217 revision THAs performed with DM constructs between July 2012 and September 2021 at a single institution. Dual mobility (DM) constructs were classified as "matched" if the acetabular and femoral components were manufactured by the same company. They were classified as "unmatched" if the acetabular and femoral components were manufactured by different companies. The primary outcome was reoperation for any reason. RESULTS: There were 136 matched DM constructs and 81 unmatched constructs. Average follow-up was 4.6 years (range, 2.0 to 9.6 years). There was no difference in reoperation rate between matched and unmatched groups (11.0 versus 13.6%, P = .576). The most common reasons for reoperation in both groups were instability and periprosthetic joint infection. There was 1 revision for intraprosthetic dislocation in the matched group. CONCLUSIONS: The use of unmatched DM components in revision THA was common and did not increase the risk of reoperation at an average of 4.6-year follow-up. This information can be helpful in operative planning, but further research on long-term survival will be necessary.

Development of a large animal rabbit model for chronic periprosthetic joint infection.

AIMS: Periprosthetic joint infections (PJIs) and osteomyelitis are clinical challenges that are difficult to eradicate. Well-characterized large animal models necessary for testing and validating new treatment strategies for these conditions are lacking. The purpose of this study was to develop a rabbit model of chronic PJI in the distal femur. METHODS: Fresh suspensions of Staphylococcus aureus (ATCC 25923) were prepared in phosphate-buffered saline (PBS) (1 × 109 colony-forming units (CFUs)/ml). Periprosthetic osteomyelitis in female New Zealand white rabbits was induced by intraosseous injection of planktonic bacterial suspension into a predrilled bone tunnel prior to implant screw placement, examined at five and 28 days (n = 5/group) after surgery, and compared to a control aseptic screw group. Radiographs were obtained weekly, and blood was collected to measure ESR, CRP, and white blood cell (WBC) counts. Bone samples and implanted screws were harvested on day 28, and processed for histological analysis and viability assay of bacteria, respectively. RESULTS: Intraosseous periprosthetic introduction of planktonic bacteria induced an acute rise in ESR and CRP that subsided by day 14, and resulted in radiologically evident periprosthetic osteolysis by day 28 accompanied by elevated WBC counts and histological evidence of bacteria in the bone tunnels after screw removal. The aseptic screw group induced no increase in ESR, and no lysis developed around the implants. Bacterial viability was confirmed by implant sonication fluid culture. CONCLUSION: Intraosseous periprosthetic introduction of planktonic bacteria reliably induces survivable chronic PJI in rabbits. Cite this article: Bone Joint Res 2021;10(3):156-165.

Squamous epithelial cell presence reduces accuracy of urinalysis for prediction of positive urine cultures.

BACKGROUND: Diagnostic value of urinalysis specimens contaminated with squamous epithelial cells (SEC) from the genital surfaces is assumed to be limited compared to clean-catch samples. However, no studies have quantified the change in predictive value in the presence of SECs for individual urinalysis markers. METHODS: In a retrospective, single center cohort study, we analyzed all urine cultures sent from the ED over a 26-month period with corresponding urinalysis results. Cultures were classified as positive with growth of >104 colony forming units of pathogenic bacteria, negative if no growth, or contaminated for all other results. UA specimens were classified as contaminated or clean based on SEC presence. Accuracy of urinalysis markers for prediction of positive cultures was calculated as an area under the curve (AUC) and was compared between contaminated and clean UA specimens. RESULTS: 6490 paired UA and urine cultures were analyzed, consisting of 3949 clean and 2541 contaminated samples. SEC presence was less common with male gender, older age, and smaller BMI. Urine cultures were 19.2% positive overall, and SECs were more common in contaminated cultures. AUCs for individual markers ranged from 0.557 to 0.796, with pyuria, bacteriuria, and leukocyte esterase having higher AUC in clean samples over contaminated. CONCLUSION: Analysis of AUC for individual urinalysis markers showed reduced diagnostic accuracy in the presence of SECs. SEC presence also reflected much higher rates of contaminated cultures. These results support the reduced reliance on contaminated UA specimens for ruling in UTI in ED patients.

Volar Carpus Dislocation Following Proximal Row Carpectomy for Scapholunate Advanced Collapse: A Rare Complication.

Scapholunate advanced collapse (SLAC) is a frequently encountered cause of wrist arthritis. For stage 2 disease, proximal row carpectomy (PRC) is an accepted treatment for which the literature has documented satisfactory outcomes and generally low complication rates. However, we report a case of SLAC wrist treated with PRC complicated by postoperative volar dislocation of carpus, to our knowledge a complication not yet reported in the literature. The patient developed atraumatic volar carpus dislocation after a routine PRC. This was treated with subsequent return to the operating room with closed reduction and percutaneous pinning of the wrist. Adequate reduction of the carpal dislocation was achieved and maintained after removal of pins. This case shows that closed reduction and percutaneous pinning is a valid option in this rare complication.

Handheld Navigation Device and Patient-Specific Cutting Guides Result in Similar Coronal Alignment for Primary Total Knee Arthroplasty: a Retrospective Matched Cohort Study.

BACKGROUND: Proper alignment of total knee arthroplasty (TKA) is essential for TKA function and may reduce the risk of aseptic failure. Technologies that prevent malalignment may reduce the risk of revision surgery. QUESTIONS/PURPOSES: The purpose of this study was to compare two competing TKA systems that purport improved alignment: patient-specific instrumentation (PSI), and a handheld portable navigation device (NAV). METHODS: After IRB approval, 49 consecutive PSI TKAs (40 patients) were matched based on preoperative characteristics to 49 NAV TKAs (40 patients) performed by a single surgeon. A blinded observer measured alignment on digital radiographs. Operating room records were reviewed for procedure times. Two-tailed paired sample t tests and McNemar's test were used as appropriate. Alpha level was 0.05 for all tests. RESULTS: Preoperative cohort characteristics were not different. Mean postoperative long-leg mechanical alignment was within ±1° of neutral for both groups, although statistically different (p = 0.026). There were no other significant differences in coronal alignment. PSI exhibited significantly greater posterior tibial slope (4.4°) compared to NAV (2.7°) (p = 0.004); PSI resulted in significantly more outliers (>6°; p = 0.004). Procedure time for unilateral TKAs was lower for PSI (74.4 min) compared to that for NAV (80.6 min; p = 0.023). CONCLUSION: NAV and PSI technologies provided excellent coronal plane alignment. NAV was better for sagittal tibial slope, while PSI procedure times were shorter for unilateral TKA. The impact of these technologies on patient-reported outcomes and TKA survivorship is controversial and should be the focus of future research.

Arthroscopic Management of Full-Thickness Rotator Cuff Tears in Major League Baseball Pitchers: The Lateralized Footprint Repair Technique.

Clinical outcomes of surgical management of full-thickness rotator cuff tears in professional baseball players have been uniformly poor. We conducted a study to investigate return-to-play data and functional performance using a novel arthroscopic repair technique. We hypothesized that arthroscopic rotator cuff repair would result in a high rate of return to professional pitching and favorable functional outcomes. We identified 6 consecutive Major League Baseball (MLB) pitchers who underwent surgical repair of full-thickness rotator cuff injuries using the lateralized footprint repair technique. At most recent follow-up, patients were evaluated to determine their ability to return to athletic activity. Functional outcomes were also assessed using player performance statistics. By mean follow-up of 66.7 months (range, 23.2-94.6 months), 5 (83%) of the 6 pitchers had returned to their preinjury level of competition for at least 1 full season. Despite the high rate of return to MLB play, few pitchers resumed pitching productivity at their preoperative level; mean number of innings pitched decreased from 1806.5 to 183.7. A slight performance reduction was also found in a comparison of preoperative and postoperative pitching statistics. Of note, the return rate was higher for players over age 30 years than for those under 30 years. Overhead athletes require a delicate balance of shoulder mobility and stability to meet functional demands. Anatomical adaptations at the glenohumeral joint should be considered when performing rotator cuff repair in these patients in order to preserve peak functional performance. This novel repair technique affords a high rate of return to MLB play, though elite overhead throwers should be counseled that pitching productivity might decrease after surgery.

Does a prior hip arthroscopy affect clinical outcomes in metal-on-metal hip resurfacing arthroplasty?

The effect of a prior hip arthroscopy on the outcome of a subsequent metal-on-metal hip resurfacing arthroplasty (HRA) has not been studied. Forty-three patients received an HRA after a prior hip arthroscopy (arthroscopy cohort). A 1:2 matching analysis was performed to formulate a control cohort of 86 patients. Range of motion, Harris Hip Score, University of California at Los Angeles activity score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and Short Form-12 scores were assessed at 6 weeks, 3 months, 6 months, 1 year, and most recent follow-up visits. At 6-week follow-up, the arthroscopy cohort showed a decreased WOMAC score compared with the control cohort (72.9 [SD, 15.5] vs 80.5 [SD, 11.8], respectively; P = .05). However, no significant difference was appreciated between the 2 cohorts for any of the clinical indices measured after 6 weeks postoperatively. This study shows that a prior hip arthroscopy does not appear to affect the short-term, clinical outcomes of a metal-on-metal HRA.

Patient specific cutting guides versus an imageless, computer-assisted surgery system in total knee arthroplasty.

BACKGROUND: Patient specific cutting guides (PSC) in total knee arthroplasty (TKA) have recently been introduced, in which preoperative 3-dimensional imaging is used to manufacture disposable cutting blocks specific to a patient's anatomy. The purpose of this study was to compare the alignment accuracy of PSC to an imageless CAS system in TKA. METHODS: Thirty-seven patients (41 knees), received a TKA using an imageless CAS system. Subsequently, 38 patients (41 knees), received a TKA using a MRI-based, PSC system. Postoperatively, standing AP hip-to-ankle radiographs were obtained, from which the lower extremity mechanical axis, tibial component varus/valgus, and femoral component varus/valgus mechanical alignment were digitally measured. Each measurement was performed by two blinded, independent observers, and interclass correlations were calculated. A student's two-tailed t test was used to compare the two cohorts (p-value<0.05=significant). RESULTS: In the PSC cohort, 70.7% of patients had an overall alignment within 3° of a neutral mechanical axis (vs. 92.7% with CAS, p=0.02), 87.8% had a tibial component alignment within 2° of perpendicular to the tibial mechanical axis (vs. 100% with CAS, p=0.04), and 90.2% had a femoral component alignment within 2° of perpendicular to the femoral mechanical axis (vs. 100% with CAS, p=0.2). Interclass correlation coefficients were good to excellent for all radiographic measurements. CONCLUSION: While PSC techniques appear sound in principle, this study did not demonstrate patient specific cutting guides to obtain the same degree of overall mechanical and tibial component alignment accuracy as a CAS technique. LEVEL OF EVIDENCE: III: Retrospective cohort study.

Perioperative complications in patients undergoing peripheral nerve surgery.

INTRODUCTION: With increasing indications for and volume of patients undergoing peripheral nerve surgery, it becomes imperative that complication rates are monitored. This study looks at complication rates in all types of peripheral nerve surgery, develops a complication classification system, and defines the most common variables associated with failures and complications. METHODS: All peripheral nerve procedures performed by the senior author during a consecutive 6-year period were retrospectively reviewed. Complications occurring within the first 30 postoperative days were recorded and classified into minor, intermediate, or major. RESULTS: A total of 5219 procedures were performed on 1819 patients in all areas of the body (head and neck, trunk, and upper and lower extremities). The total complication rate was 2.91%, with a minor complication rate of 2.47%, intermediate complication rate of 0.44%, and major complication rate of 0%. CONCLUSIONS: This study confirms that peripheral nerve surgery can be safely performed with a very low complication rate if patients are properly selected and the surgeon is appropriately trained. A classification system for complications after peripheral nerve surgery and the most common variables associated with failures and complications are presented.

Production and characterisation of antibodies against isolated placental retroviral-like particles.

The mammalian genomic DNA is known to contain a variety o f endogenous proviruses but their expression is usually restricted to reproductive tissues such as the placenta and a variety of human tumour cells. More definitive characterization of retroviral gene products has been hampered by unavailability of specific biological reagents. In this study, polyclonal and a total of six monoclonal antibodies (mAbs) were raised against endogenous (intact) retroviral particles isolated from human placental villous tissue. These antibodies were characterized using immunohistochemical and biochemical methods. Five polyclonal antibodies and one mAb (RV1-17) showed strong specific immunohistochemical and immunogold staining with submembraneous structures within placental syncytiotropblast. The reactivity of these antibodies was consistent with the pattern of apical syncytiotrophoblastic budding of retroviral particles previously reported in ultrastructural analyses.