BACKGROUND: The proximal femur is a common site of bone metastasis. The Mirels\' score is a frequently utilized system to identify patients at risk for pathologic fracture and while it has consistently demonstrated strong sensitivity, specificity has been relatively poor. Our group previously developed a Modified Mirels\' scoring system which demonstrated improved ability to predict cases at risk of fracture in this patient population through modification of the Mirels\' location score. The purpose of the present study is to internally validate this newly developed scoring system on an independent patient series.
METHODS: Retrospective review was performed to identify patients who were evaluated for proximal femoral bone lesions. Patients were stratified into one of two groups: 1) those who went on to fracture within 4 months after initial evaluation (Fracture Group) and 2) those who did not fracture within 4 months of initial evaluation (No Fracture Group). Retrospective chart review was performed to assign an Original Mirels\' (OM) Score and Modified Mirels\' (MM) score to each patient at the time of initial evaluation. Descriptive statistics, logistic regression, receiver operating curve, and net benefit analyses were performed to determine the predictability of fractures when utilizing both scoring systems.
RESULTS: The use of the MM scoring improved fracture prediction over OM scoring for patients observed over a 4 month follow up based on logistic regression. Decision curve analysis showed that there was a net benefit using the MM score over the OM scoring for a full range of fracture threshold probabilities. Fracture prevalence was similar for current internal validation dataset when compared to the dataset of our index study with a comparable reduction in misclassification of fracture prediction when utilizing the modified scoring system versus the original.
CONCLUSIONS: Use of MM scoring was found to improve fracture prediction over OM scoring when tested on an internal validation set of patients with disseminated metastatic lesions to the proximal femur. The improvement in fracture prediction demonstrated in the present study mirrored the results of our index study during which the MM system was developed.

Hydatidosis, is a zoonotic disease prevalent in sheep-raising regions globally. Musculoskeletal hydatidosis is uncommon and usually remains asymptomatic over a long period. The detection of musculoskeletal hydatidosis often signifies extensive cyst spread within the bone marrow cavity, making treatment difficult with a high recurrence rate. Unlike the conventional surgical approach for visceral hydatid cysts, treating osseous hydatidosis requires a strategy akin to oncologic therapy. We report a rare case of primary hydatidosis affecting the ulna and adjacent soft tissue in a 58-year-old woman. She presented with a painless forearm mass evolving over six years, accompanied by recent onset tenderness and restricted elbow joint mobility. Imaging revealed a cystic mass in the forearm, an intra-ulnar bone lesion, and an olecranon fracture. The primary diagnosis of musculoskeletal hydatidosis was made based on clinical findings and radiological imaging. Treatment involved resection of 2/3 of the proximal ulna and pericystectomy for the soft tissue hydatid cyst. Diagnosis of musculoskeletal hydatidosis is vital for effective preoperative planning, as internal fixation often fails without eradicating the infestation. Treatment typically involves radical operation with wide excision of the affected bone and adjacent joint structures, coupled with chemotherapy. Clinicians in endemic regions should consider musculoskeletal hydatidosis in the differential diagnosis of osteolytic lesions and slow-growing cystic masses. Diagnosis relies on clinical, serological, and radiological assessments.

UNASSIGNED: Accurate comparison of prophylactic surgical treatment (PST) to after fracture treatment (AF) of patients with femoral metastatic disease requires more accurately identifying patients for impending fracture, such as with CT-based structural rigidity analysis (CTRA). This study compares a more accurately defined PST group (of impending fractures defined by CTRA) to AF for metastatic femoral disease.
UNASSIGNED: PST patients were enrolled and treated by the PI in a longitudinal multicenter study of impending pathologic fractures evaluated for accuracy by CTRA. The AF patients were also treated by the senior author and were identified by retrospective chart review. Fifty-five patients were treated surgically for metastatic femoral lesions and were divided into three groups for the purpose of this study: Group I (AF), Group II (PST-high), and Group III (PST-low). Demographic information, comorbidities, and clinical variables of interest were collected by retrospective chart review; cost data was collected by collaboration with our hospital financial personnel (office of the Chief Financial Officer).
UNASSIGNED: Survival showed statistically significant differences favoring Group II. Transfusions in Group I were nearly twice those of Groups II and III, but there was no statistically significant (NS) difference between groups. Estimated blood loss (EBL) was generally with NS difference. Similarly, there were NS differences in LOS between groups. Discharge disposition showed statistically significant differences between groups (P=0.012, global). Discharge to home was highest in Group II (76%) and lowest in Group I (27%). Discharge to rehab was lowest in Group II (24%) and highest in Group I (47%). There were no discharges to hospice or morgue in Group II, while both occurred in Group I. Mean direct and total costs were highest in Group I ($18,837 and $31,997, respectively) and lowest in Group II ($16,094 and $27,357) but the differences were NS.
UNASSIGNED: This study shows benefits of PST over AF in a group of PST patients more accurately defined to have impending pathologic fractures by CTRA definition.

BACKGROUND: The photodynamic bone stabilization system (PBSS) was was developed in 2010, and in 2018 gained FDA approval in the United States. Given its relative novelty, our analysis sought to analyze the available literature exploring the indications, outcomes, and complications of the PBSS.
METHODS: We performed a systematic review (PROSPERO registration of study protocol: CRD42022363065, October 8th, 2022). PubMed, EBSCOHost, and Google Scholar electronic databases were queried to identify articles evaluating PBSS in the treatment of pathologic or traumatic fractures between January 1 2010 and 15 October 2022. The quality of the included studies was assessed using the Methodological Index for Nonrandomized Studies tool.
RESULTS: Our initial search yielded 326 publications, which were then screened for appropriate studies that aligned with the purpose of our review. A total of thirteen studies, comprising seven case series, four case reports, and two cohort studies. The total sample size of the included studies consisted of 345 patients, with 242 females (70%) and 103 males (30%). The implants were most commonly utilized in the humerus (41%), radius (12%), and metacarpal (12%). The most common complications were related to broken implants (5%) and dislocation (1%). Most studies reported complete fracture healing and return of full strength and range of motion.
CONCLUSIONS: Despite being a relatively novel technology, PBSS appears to be a viable option for fracture stabilization. Most studies included in our analysis reported complete fracture healing and return of function with minimal complications.

UNASSIGNED: Zoledronic acid (ZOL) is a third-generation bisphosphonate with a higher affinity for bone resorption areas than earlier bisphosphonates (i.e., pamidronate, PAM). In human medicine, ZOL provides improved bone pain relief and prolonged time to skeletal-related events compared to its older generational counterparts. Preclinical studies have investigated its role as an anti-neoplastic agent, both independently and synergistically, with radiation therapy (RT). ZOL and RT act synergistically in several neoplastic human cell lines: prostate, breast, osteosarcoma, and fibrosarcoma. However, the exact mechanism of ZOL\'s radiosensitization has not been fully elucidated.
UNASSIGNED: We investigated ZOL\'s ability to induce apoptosis in canine osteosarcoma cell lines treated with various doses of megavoltage external beam radiotherapy. Second, we evaluated cell cycle arrest in ZOL-treated cells to assess several neo-adjuvant time points. Finally, we treated 20 dogs with naturally occurring appendicular OS with 0.1 mg/kg ZOL IV 24 h before receiving 8 Gy of RT (once weekly fraction x 4 weeks).
UNASSIGNED: We found that apoptosis was increased in all ZOL-treated cell lines compared to controls, and the combination of ZOL and RT resulted in dissimilar apoptosis between Abrams and D-17 and HMPOS cell lines. Cell cycle arrest (G2/M phase) was minimal and variable between cell lines but perhaps greatest at 48 h post-ZOL treatment. Only 10% of dogs treated with ZOL and RT developed pathologic fractures, compared to 44% of dogs historically treated with PAM and RT (p = 0.027).
UNASSIGNED: ZOL and RT appear to be a well-tolerated combination treatment scheme for non-surgical candidates; future studies must elucidate the ideal timing of ZOL.

UNASSIGNED: Impending and complete pathologic fractures of the distal humerus are rare complications of metastatic cancer. Surgical treatment aims to quickly restore function and minimize pain. Plate and screw fixation (PSF) is a common method for addressing these lesions, but unlike in orthopaedic trauma, there are no clear guidelines for best management. While dual PSF theoretically provides better support and reduces the chance of reoperation due to tumor progression, single PSF is currently the more common choice.
UNASSIGNED: Between March 2008 and September 2021, 35 consecutive patients who underwent PSF for distal humerus metastasis or multiple myeloma were retrospectively reviewed. The proportion of patients who developed various postoperative complications, including infection, nonunion, deep vein thrombosis, tumor progression, and radial nerve palsy, as well as those requiring reoperation, was calculated. Mann-Whitney U test, Pearson\'s chi-squared, and Fisher\'s exact test were used to investigate differences between the single and dual PSF groups with statistical significance defined as p ≤ 0.05.
UNASSIGNED: There was no significant difference (p = 0.259) in revision rate, although 3 of 21 (14.3 %) single PSF patients required reoperation compared to 0 of 14 (0.0 %) dual PSF patients. The revisions were performed in one patient due to refracture and in two patients due to tumor progression. Although not statistically significant, a larger percentage of single PSF patients developed a postoperative complication compared to dual PSF patients [odds ratio 0.42 (95 % confidence interval 0.071 to 2.5); p = 0.431]. Single PSF did lead to shorter operative time compared to dual PSF [p < 0.001].
UNASSIGNED: Dual PSF is non-inferior to single PSF and potentially results in fewer reoperations and postoperative complications in distal humerus pathologic lesions, although it leads to longer operative time. The current study is limited by small sample size due to the rarity of distal humerus metastatic lesions.

UNASSIGNED: Pathologic phalangeal fracture is a common initial presentation of solitary enchondroma of the finger. Enchondromas of the middle phalanx are most frequently associated with post-operative range of motion deficits. This report describes a case in which the use of Kirschner wires (K-wires) and allograft bone were used to salvage finger motion following surgical fixation of pathologic fracture of a middle phalanx enchondroma with extensor tendon injury.
UNASSIGNED: A 37-year-old right hand dominant woman presents with pathologic fracture of the left index finger middle phalanx. The patient elected for surgical intervention to stabilize fracture and enable early motion at the proximal interphalangeal joint (PIP). Surgical fixation involved tumor curettage, fracture stabilization and length preservation with longitudinal K-wires, allograft bone with hardening properties to fill the bony defect, and dorsal K-wires for securing the extensor tendon. At follow-up 11 months postoperatively, the allograft had almost completely resolved, and the patient had regained PIP flexion of 90° and full extension.
UNASSIGNED: Pathologic fracture of middle phalanx enchondroma is prone to complication by extensor tendon injury and associated post-operative loss of motion. Bone grafting and Kirschner wire fixation allowed for early mobilization of finger motion and thus may be a useful technique for use in treatment of other pathologic fractures.

UNASSIGNED: Information on dogs that undergo radiation therapy (RT) with non-stereotactic protocols in addition to surgical stabilization with implant placement for treatment of bone tumors is limited.
UNASSIGNED: Our primary objectives were to describe the clinical characteristics as well as short- and long-term outcomes, including complications, function, and disease progression, in dogs that underwent both surgical stabilization with implant placement and non-stereotactic RT for local treatment of a bone tumor.
UNASSIGNED: A bi-institutional retrospective case series was performed.
UNASSIGNED: Eight client-owned dogs that underwent both surgical stabilization with implant placement and non-stereotactic RT for local treatment of a bone tumor were included.
UNASSIGNED: Tumor types included osteosarcoma or suspected osteosarcoma (5), plasma cell tumor (2), and grade 3 fibrosarcoma (1). Radiation protocols were hypofractionated (palliative intent) in 5 dogs and fractionated (definitive intent) in 3 dogs. Five dogs experienced complications following both RT and surgery, including grade 1 complications in two dogs, a grade 2 complication in one dog, both grade 1 and 2 complications in one dog, and both grade 2 and 3 complications in one dog. Clinical signs subjectively improved in all dogs that had outcomes relative to function documented post-surgery/RT (7). Of these 7 dogs, 4 maintained long-term improvement in function and clinical signs, whereas 3 experienced subsequent recurrence/progression of clinical signs at a median of 133 days (range 91-186) postoperatively in association with biomechanical complications (screw loosening), surgical site infection, and local disease progression in 1 dog each; subsequent treatment resulted in improved clinical signs for each of these 3 dogs, such that overall good long-term functional outcomes were experienced. No dogs required amputation or additional vertebral surgery as salvage for local disease control or palliation. The median progression free interval was 206 days (range 25-1078), and the median survival time was 253 days (range 122-1078) with 1 additional dog lost to follow-up at 575 days. Two dogs experienced local disease progression, and 6 dogs experienced systemic disease progression; both dogs that developed local disease progression received palliative intent RT protocols.
UNASSIGNED: In this cohort, dogs with primary bone tumors that underwent surgical stabilization with implant placement and hypofractionated or fractionated non-stereotactic RT for local treatment had a low incidence of major complications, good limb function and ambulation post-treatment, and relatively prolonged survival times despite disease progression.

UNASSIGNED: A retrospective study was conducted to compare the mid-term clinical efficacy between percutaneous calcium sulfate injection (PCSI) and localized scrape bone grafting (LSBG) in using titanium elastic nails treat humerus pathologic fractures caused by unicameral bone cysts in children.
UNASSIGNED: Humerus pathologic fracture patients with unicameral bone cysts in our pediatric orthopedic department from January 2015 to January 2020 were retrospectively analyzed. Patients were divided into two groups, namely the PCSI group and the LSBG group, based on the type of bone grafting material they received. Preoperative assessments were made in both groups using the Cyst Index and Cyst activity. During the perioperative phase, assessments were made regarding operative time, bleeding, postoperative VAS scores, and the frequency of reoperation within 2 years. Clinical outcomes were evaluated using the Capanna scale at the last follow-up, and the occurrence of re-fractures during the follow-up period.
UNASSIGNED: A total of 22 patients were included, with a mean follow-up duration of 33.5 ± 5.8 months. No significant differences were found between the two groups in terms of Cyst Index and Cyst activity before the operation. The operative time, bleeding, and postoperative VAS scores in the PCSI group were found to be lower than those in the LSBG group (P < 0.05). The PCSI group also showed a higher frequency of reoperation within 2 years compared to the LSBG group (P < 0.05). However, no significant differences were observed between the two groups in terms of Capanna scale scores at the last follow-up and the incidence of re-fractures during follow-up.
UNASSIGNED: Both titanium elastic nails (TEN) combined with PCSI or LSBG were found to be safe and effective treatments for humerus pathologic fractures caused by unicameral bone cysts in children. PCSI is considered as a less invasive option with shorter operative times, less bleeding, and reduced postoperative pain, although it comes with the risk of multiple injections. On the other hand, LSBG is considered as a more invasive option for the treatment of active bone cysts but is associated with a lower recurrence rate.

UNASSIGNED: Immune checkpoint inhibitors (ICIs) have noticeably enhanced oncologic outcomes associated with patient survival in different subtypes of metastatic cancer by enhancing cytotoxic T-cell activity. ICI-associated toxicities are often referred to as immune-related adverse events (irAEs) and occur in nearly every organ system. However, the effect of ICIs on the skeleton is poorly examined, and only a few case series have been published.
METHODS: A 37-year-old man who presented with pathologic fractures of the right proximal humerus during adjuvant pembrolizumab therapy following laparoscopic radical nephrectomy for right renal cell carcinoma.
UNASSIGNED: ICIs are associated with various irAEs virtually affecting all host tissues, most of which have been described well by pharmacovigilance analyses. However, to date, very few studies have examined the effects of ICI on the skeleton.
CONCLUSIONS: Urologic oncologists and urologists should be aware of the rare but potentially fatal bone side effects of ICIs.