Utility of iliac crest tetracycline-labelled bone biopsy in osteoporosis and metabolic bone disease: An evaluation of 95 cases over a period of 25 years.

Background: Metabolic bone diseases (MBD) are typically diagnosed by non-invasive imaging and clinical biomarkers. However, imaging does not provide structural information, and biomarkers can be transiently affected by many systemic factors. Bone biopsy and pathologic evaluation is the gold standard for diagnosis of MBD, however, it is rarely utilized. We describe our technique for iliac crest tetracycline-labelled bone using a cannulated drill and assess the utility of bone biopsies to provide diagnostic and therapeutic guidance. Methods: In the 25-year period between March 1998 and January 2023, a total of 95 bone biopsies were performed on 94 patients for an osteological indication at Vanderbilt University Medical Center (VUMC). Patient demographics, bone biopsy indications, complications, diagnostic utility, and subsequent therapeutic guidance were retrospectively reviewed and analyzed. Results: The procedure had minimal complications and was well tolerated by patients. This technique provided good quality specimens for pathology, which helped establish a diagnosis and treatment change in most patients. Patients that had biopsy-guided treatment alterations showed significant increases in Dual-Energy X-ray Absorptiometry (DEXA) bone mineral density (BMD) scores post-biopsy and subsequent treatment. Conclusion: Despite scientific and technological progress in non-invasive diagnostic imaging, clinical biomarkers, and procedures for MBD, there remains a small but significant subset of patients who may benefit from inclusion of tetracycline-labelled bone biopsy into the diagnostic and therapeutic picture. Future prospective comparison studies are warranted. Mini abstract: Tetracycline-labelled bone biopsies are under-utilized. Biopsy led to a histological diagnosis and ensuing treatment alteration in most patients with significant increases in bone mineral density. The biopsy procedure used herein provided good specimens with low pain/adverse events. Bone biopsy remains a valuable tool in a small, though significant, subset of patients.

Use of a Cannulated, Percutaneous Expandable Reamer for Physeal Sparing Excision of a Femoral Head Chondroblastoma.

The treatment of chondroblastoma in the epiphysis of the femoral head in skeletally immature individuals is challenging and often requires surgical hip dislocation. We present a unique method of percutaneous use of an expandable reamer (X-REAM, Wright Medical) to treat a chondroblastoma of the femoral head in a 9-year-old boy without requiring surgical hip dislocation. The described technique provides access to the tumor in the proximal femoral epiphysis and local tumor control. However, the approach involves placing a cannula through the epiphyseal plate, resulting in partial premature epiphyseal closure. At 5 years after surgery, the patient has an asymptomatic leg-length discrepancy and radiographic evidence of premature physeal closure, but no restrictions on activity or evidence of local recurrence. A percutaneous expandable reamer can be used to treat chondroblastoma of the femoral head while avoiding surgical hip dislocation.

Benign Neurofibroma/Schwannoma Hybrid Peripheral Nerve Sheath Tumor of the Ulnar Nerve Harboring a Metastatic Papillary Thyroid Carcinoma Deposit: A Case Report of Tumor-to-Tumor Metastasis.

A 74-year-old man with a medical history significant for papillary thyroid cancer (PTC) presented with a rapidly enlarging grape-sized mass in his right medial arm with paresthesia in the ulnar nerve distribution. Imaging was suspicious for a peripheral nerve sheath tumor (PNST), but an ultrasound-guided biopsy was equivocal. The mass was excised with final histopathology demonstrating a benign neurofibroma/schwannoma hybrid nerve sheath tumor (N/S HNST) harboring a metastatic PTC deposit, ultimately mimicking the rare glandular schwannoma subtype. Next-generation sequencing (NGS) of the lesion demonstrated somatic variants in BRAF and TERT (common in PTC) and NF2 (common in PNSTs). After excision, the patient's nerve symptoms improved. A postsurgical PET/CT scan also showed progression in the lungs/mediastinum. Due to the metastatic nature of his PTC, he was treated with 14 mg of Lenvima (lenvatinib) daily, and his PET/CT surveillance was performed at more frequent intervals. Tumor-to-tumor metastasis (TTM) is a rare occurrence. To our knowledge, this is the first case reported on PTC metastasizing into a benign (hybrid) PNST, which mimicked glandular schwannoma. Symptomatology, imaging characteristics, NGS, and histopathological characteristics that can decipher between different benign PNST subtypes (schwannoma, neurofibroma, glandular, hybrid, etc.), malignant PNSTs (MPNSTs), and TTM are described.

Periprosthetic Fractures Through Tracking Pin Sites Following Computer Navigated and Robotic Total and Unicompartmental Knee Arthroplasty: A Systematic Review.

BACKGROUND: Use of computer-assisted navigation (CAN) and robotic-assisted (RA) surgery in total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) both necessitate the use of tracking pins rigidly fixed to the femur and tibia. Although periprosthetic fractures through tracking pin sites are rare, there is a paucity of literature on this potential complication. Therefore, the purpose of this study was to perform a systematic review of the current literature to assess the incidence and clinical outcomes of periprosthetic fractures through tracking pin sites following CAN and RA TKA and UKA. METHODS: A systematic review was performed following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines using the PubMed, MEDLINE, and Cochrane databases in April 2020. Studies were assessed for the presence of pin site fractures, fracture characteristics, and clinical outcomes. RESULTS: Seventeen clinical studies (5 case series, 1 cohort study, and 11 case reports) involving 29 pin-related fractures were included for review. The overall incidence ranged from 0.06% to 4.8%. The mean time from index arthroplasty to fracture was 9.5 weeks (range, 0 to 40 weeks). The majority of fractures occurred in the femoral diaphysis (59%). Nineteen fractures (66%) were displaced and 10 (34%) were nondisplaced or occult. The majority of cases were atraumatic in nature or involved minor trauma and were typically preceded by persistent leg pain. A transcortical pin trajectory, large pin diameter (>4 mm), diaphyseal fixation, multiple placement attempts, and the use of non-self-drilling, non-self-tapping pins were the most commonly reported risk factors for pin-related periprosthetic fractures following CAN or RA TKA. CONCLUSIONS: Surgeons should maintain a high index of suspicion for pin-related fractures in patients with ongoing leg or thigh pain after CAN or RA TKA in order to avoid fracture displacement and additional morbidity. As CAN and RA TKA have unique complication risks, the debate regarding the value of technology-assisted TKA and its cost-effectiveness continues. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Vacuum Phenomenon in the Elbow: A Case Report.

CASE: A 33-year-old man presented with a closed distal humerus fracture after a fall from scaffolding. Computed tomography demonstrated intra-articular gas, despite the lack of arthrotomy, open fracture, or skin defects. The "vacuum phenomenon" (VP), or the presence of intra-articular gas in closed injuries, has primarily been described in the axial skeleton. To our knowledge, there are no reports in fractures of the elbow. CONCLUSION: The incidence of the VP is under-reported and represents a lack of physician awareness. The VP should remain a diagnosis of exclusion; however, physicians should be aware of this phenomenon to prevent unnecessary patient harm.

Obesity and its effect on outcomes in same-day bilateral total knee arthroplasty.

BACKGROUND: The niche surgery of same-day bilateral total knee arthroplasty (sd-BTKA) continues to create debate amongst specialists in arthroplasty. To date, there is a significant lack of literature on obese patients undergoing sd-BTKA, and no study has evaluated outcomes of this procedure when compared to non-obese patients. Therefore, this study will perform a retrospective analysis to compare (I) incidence, (II) demographics, and (III) complications of sd-BTKA in non-obese, obese, and morbidly obese patients in the United States from 2009 to 2016. METHODS: The National Inpatient Sample (NIS) database was queried for all individuals that underwent sd-BTKA from 2009 to 2016. This returned 184,844 non-obese patients, 39,901 obese patients, and 20,394 morbidly obese patients. Analyzed variables included mean age, mean length of stay (LOS), race, payer, age-adjusted Charlson Comorbidity Index score, discharge disposition, hospital charges, hospital costs, and complications. Chi-square analyses and analyses of variance were utilized to assess categorical and continuous variables, respectively. RESULTS: Non-obese patients most commonly underwent sd-BTKA over the course of the study. As weight status increased, mean age decreased and the proportion of females, LOS, hospital charges and costs, and proportion of discharges to skilled nursing facilities increased. Regression analysis demonstrated obese and morbidly obese cohorts were at an overall increased odds for experiencing complications. Specifically, obese patients were at increased risk for pulmonary emboli, periprosthetic joint infections, and respiratory failures, while morbidly obese patients are at increased risk for pulmonary emboli, respiratory failures, and urinary tract infections. CONCLUSIONS: Surgeons should thoroughly evaluate the risks and benefits of performing sd-BTKA on obese and morbidly obese patients, as both confer higher overall complication rates and increased length of stay. More research is necessary to characterize the cost analysis of this procedure, as health care models continue to transition to more cost-effective procedures.