Femoral Shaft Research Articles

Long-term results and patient-reported outcomes after vascularized fibular graft use in the treatment of post-traumatic bone defects of femur shaft and tibia: A retrospective cohort and cross-sectional survey study

Post-traumatic critical-sized bone defects pose a reconstructive challenge for reconstructive surgeons. The vascularized fibula graft is a well-described treatment for osseous defects of the femur and tibia. This study aimed to assess long-term patient-reported quality of life, the success-, and complication rates in lower extremity reconstruction with vascularized fibula grafts. A retrospective cohort of 29 patients who underwent fibula graft reconstruction for critical-sized bone defects after post-traumatic tibial and femoral bone loss between 1990 and 2021 was included. To assess the health-related quality of life and return to work and satisfaction, a cross-sectional survey was performed using the short-form-36, lower extremity functional scale, and a self-made questionnaire including the DN4, satisfaction, and subjective ankle function. The median bone defect size was 8cm (IQR 9-7cm). The mental component scores were comparable to the Dutch population norm, whereas the impaired physical function scores were associated with pain (r 0.849, p<0.001). Neuropathic symptoms were reported in 7 out of 19 patients, and 11 out of 19 patients returned to normal daily activity. All respondents reported positive or neutral scores on overall satisfaction with the recovery. Bone healing was uneventful in 19 out of 29 patients. Union was achieved in 25 out of 29 patients. Persistent nonunion was observed in 4 patients, leading to amputation in 2 patients. Vascularized fibula graft use led to high union rates and limb salvage in patients with post-traumatic segmental bone loss of the tibia and femur. Patient satisfaction with the overall recovery was positive; however, functional outcomes remained impaired.

Plate fixation versus flexible intramedullary nails for management of closed femoral shaft fractures in the pediatric population: A systematic review and meta-analysis of the adverse outcomes.

Plate fixation versus flexible intramedullary nails for management of closed femoral shaft fractures in the pediatric population: A systematic review and meta-analysis of the adverse outcomes.

Response to Letter to the Editor-Plate fixation versus flexible intramedullary nails for management of closed femoral shaft fractures in the paediatric population: A systematic review and meta-analysis of the adverse outcomes (J Child Orthop 2023,17(5),442-452).

Response to Letter to the Editor-Plate fixation versus flexible intramedullary nails for management of closed femoral shaft fractures in the paediatric population: A systematic review and meta-analysis of the adverse outcomes (J Child Orthop 2023,17(5),442-452).

Preoperative abaloparatide plus zoledronate treatment accelerates femoral bone healing in rats following osteotomy.

Purpose: We investigated the potential efficacy of abaloparatide (Abalo) and zoledronate (ZA) combination therapy for accelerating femoral union in a rat osteotomy model. Methods: Nine-week-old male Sprague-Dawley rats were randomly divided into four groups (n = 14 per group): control, abaloparatide (Abalo, 30μg/kg via subcutaneous injection [s.c.] 5 times per week for 6weeks), zoledronate (ZA; 0.1mg/kg via s.c., single dose), and Abalo + ZA. Rats were then subjected to unilateral osteotomy of the femoral shaft, followed by osteosynthesis with intramedullary nailing to establish bone healing models. At 2 and 4weeks after osteotomy, both femurs were removed from seven rats per group for soft X-ray imaging to evaluate bone union and microcomputed tomography (micro-CT) for bone morphometric evaluation. Blood samples were collected from all rats every 2week starting 6weeks pre- to 4weeks postosteotomy. Toluidine blue staining was used for histopathological evaluation of the undecalcified specimens. Results: Soft X-ray imaging revealed accelerated callus formation, callus maturation, and fracture line closure in Abalo and Abalo + ZA groups compared to ZA and control groups. Micro-CT demonstrated greater cortical bone and trabecular bone to total volume ratios in contralateral (left) femurs of the Abalo + ZA group compared to the Abalo group. Both trabecular and cortical bone mineral densities were also greater in contralateral femurs of the Abalo + ZA group compared to Abalo and ZA groups. Conclusion: These findings suggest substantial additive or synergistic efficacy of abaloparatide plus zoledronate combination therapy for accelerating bone healing following osteotomy and for maintaining normal bone health.

SIMBA-A Single-Puncture Approach to Lower Limb Block.

Peripheral nerve blocks provide a safe and reliable alternative in the anesthetic management of femur fractures in elderly subpopulations associated with significant comorbidities. Single-Insertion Multiple Nerve Block Anesthesia (SIMBA) is a technique where a single needle insertion is used to block all four nerves that supply the femur shaft: the femoral nerve, obturator nerve, lateral femoral cutaneous nerve, and sciatic nerve. The authors performed this technique in 11 cardiac compromised geriatric patients with midshaft/distal femur fractures, and the surgery was conducted successfully without any significant hemodynamic change and good postoperative analgesia.

Leptin signalling altered in infantile nephropathic cystinosis-related bone disorder.

The CTNS gene mutation causes infantile nephropathic cystinosis (INC). Patients with INC develop Fanconi syndrome and chronic kidney disease (CKD) with significant bone deformations. C57BL/6 Ctns-/- mice are an animal model for studying INC. Hyperleptinaemia results from the kidney's inability to eliminate the hormone leptin in CKD. Ctns-/- mice have elevated serum leptin concentrations. Leptin regulates bone metabolism through its receptor that signals further via the hypothalamic melanocortin 4 receptor (MC4R). Leptin signalling may affect bone health in Ctns-/- mice. We first defined the time course of bone abnormalities in Ctns-/- mice between 1 and 12months of age. We used both genetic and pharmacological approaches to investigate leptin signalling in Ctns-/- mice. We generated Ctns-/-Mc4r-/- double knockout mice. Bone phenotype of Ctns-/-Mc4r-/- mice, Ctns-/- mice and wild type (WT) mice at 1, 4, and 9months of age were compared. We then treated 12-month-old Ctns-/- mice and WT mice with a pegylated leptin receptor antagonist (PLA) (7mg/kg/day, IP), a MC4R antagonist agouti-related peptide (AgRP) (2nmol, intracranial infusion on days 0, 3, 6, 9, 12, 15, 18, 21, 24, and 27), or vehicle (normal saline), respectively, for 28days. Whole-body (BMC/BMD, bone area) and femoral bone phenotype (BMC/BMD, bone area, length and failure load) of mice were measured by DXA and femoral shaft biochemical test. We also measured lean mass content by EchoMRI and muscle function (grip strength and rotarod activity) in mice. Femur protein content of JAK2 and STAT3 was measured by ELISA kits, respectively. Bone defects are present in Ctns-/- mice throughout its first year of life. The deletion of the Mc4r gene attenuated bone disorder in Ctns-/- mice. Femoral BMD, bone area, length, and strength (failure load) were significantly increased in 9-month-old Ctns-/-Mc4r-/- mice than in age-matched Ctns-/- mice. PLA and AgRP treatment significantly increased femoral bone density (BMC/BMD) and mechanical strength in 12-month-old Ctns-/- mice. We adopted the pair-feeding approach for this study to show that the protective effects of PLA or AgRP on bone phenotype are independent of their potent orexigenic effect. Furthermore, an increase in lean mass and in vivo muscle function (grip strength and rotarod activity) are associated with improvements in bone phenotype (femoral BMC/BMD and mechanical strength) in Ctns-/- mice, suggesting a muscle-bone interplay. Decreased femur protein content of JAK2 and STAT3 was evident in Ctns-/- mice. PLA or AgRP treatment attenuated femur STAT3 content in Ctns-/- mice. Our findings suggest a significant role for dysregulated leptin signalling in INC-related bone disorder, either directly or potentially involving a muscle-bone interplay. Leptin signalling blockade may represent a novel approach to treating bone disease as well as muscle wasting in INC.

A new insight for investigating the prenatal and postnatal ossification centers of pelvic and femur bones in white New Zealand rabbits (Oryctolagus cuniculus) using 3D CT, double stain technique, and morphometry

BackgroundThe ossification centers in rabbit limbs are related to fetal age and bone maturation. Objective: To address the limited studies on ossification in the hind limbs of New Zealand rabbits, we investigated the prenatal and postnatal development of the pelvic and femur bones. MethodsDouble staining with Alcian Blue and Alizarin Red, computed tomography (CT), and 3D reconstruction were employed to visualize and analyze ossification centers in detail. ResultsUsing double staining, we observed these patterns: At prenatal days 18 and 21, ossification centers appeared in the ilium. By prenatal days 23 and 25, ossification began in the ischium. On postnatal day 1, ilium ossification centers spread across most of the ilium wings, except for the iliac crest, and new centers appeared in the pubis and cotyloid bones. Most bones had ossified by the third week and one month postnatal, except for the iliac crest and ischial tuberosity. At 1.5 months, both were fully ossified. On day 18 post coitum, an ossification center was visible in the middle of the femur shaft. By day 28 post coitum, ossification extended through the shaft, and postnatally, new ossification spots appeared at the extremities by day one and week one. By the third week, complete ossification of the femur head, lesser trochanter, third trochanter, medial condyle, and lateral condyle was observed. At 1.5 months, the entire proximal extremity was ossified. Conclusion3D CT provided clear imaging of ossification progression in the pelvic and femur bones. This study enhances our understanding of vertebrate skeletal development.

Metastatic cancer in a medieval skeleton from the Principality of Liechtenstein.

We present a presumptive case of metastatic carcinoma in an individual from the 11th/12th century CE from Vaduz, Principality of Liechtenstein. The skeleton exhibits extensive new bone formation in the axial skeleton and the proximal humerus and femur. Radiological examinations revealed further sclerotic lesions in the clavicles, the manubrium, the sternum, the femoral diaphysis, and possibly the frontal. The pelvic bones and the sacrum, as well as the spine, are the most heavily affected skeletal regions. The newly formed bone in some lesions has a "sun-burst" appearance. The sex and age at death of the individual, the distribution and the osteoblastic nature of the lesions suggest that prostate carcinoma is the most likely primary tumor.

Osseous metastases of uterine leiomyosarcoma: Analysis of survival & surgical management

BackgroundUterine leiomyosarcoma represents a seldom-encountered subset within the spectrum of uterine malignancies. Occurrences of appendicular skeletal metastases in uterine leiomyosarcomas are infrequent. In this study, we examined patient surveys to elucidate the clinical characteristics and outcomes of individuals with uterine leiomyosarcoma exhibiting metastatic dissemination to these anatomical regions. We hypothesized that palliative surgical treatment would have no effect on survival in patients diagnosed with uterine leimyosarcoma with appendicular bone metastases. MethodsOne hundred fourteen patients diagnosed with uterine leiomyosarcoma and treated at the Department of Oncologic Orthopedics at XXX hospital from 2004 to 2021 met the criteria for inclusion in this retrospective cohort study. The study specifically encompassed patients with histopathologically confirmed appendicular bone metastases secondary to uterine leiomyosarcoma, who underwent either surgical intervention or conservative treatment. Exclusion criteria involved patients with exclusive vertebral bone metastases, as well as those lacking essential examination and follow-up data. Notably, the study included nine follow-up patients with at least 2 years of follow-up who developed appendicular skeletal metastases during the follow-up period. ResultsOf the 9 patients, 3 had humeral metastases, 2 had femoral metastases, 1 had femoral and diffuse pelvic metastases, and the other 3 had pelvic metastases. Bone metastases occurred at a mean of 33.3 ± 32.4 months (range 3 - 108) after the diagnosis. After bone metastasis, 6 patients died after an average of 40.3 ± 26.7 months (range 12–84 months). One patient with a pathologic fracture in the proximal humerus underwent resection arthroplasty, 1 patient with metastases in the proximal femur underwent resection arthroplasty, 2 patients with metastases to the femoral shaft underwent curettage-cementation (C&C) and intramedullary nailing, and 1 patient with persistent pelvic pain underwent C&C. No surgery was performed in the other patients. ConclusionIn patients diagnosed with uterine leiomyosarcomas, survival did not differ between palliative surgery and conservative treatment after appendicular bone metastases. Patient assessment should be individualized, and overall health should be evaluated before palliative surgery is performed. Level of EvidenceIV.

THE FIRST 200 CERAMIC-ON-CERAMIC HIP RESURFACING IMPLANTS AT MINIMUM TWO-YEAR FOLLOW-UP

Hip resurfacing arthroplasty (HRA) is a bone conserving alternative to total hip arthroplasty. We present the early 2-year clinical and radiographic follow-up of a novel ceramic-on-ceramic (CoC) HRA in an international multi-centric cohort.Patients undergoing HRA between September 2018 and January 2021 were prospectively included. Patient-reported outcome measures (PROMS) in the form of the Forgotten Joint Score (FJS), HOOS Jr, WOMAC, Oxford Hip Score (OHS) and UCLA Activity Score were collected preoperatively and at 1- and 2-years post-operation. Serial radiographs were assessed for migration, component alignment, evidence of osteolysis/loosening and heterotopic ossification formation.200 patients were identified to have reached 2-year follow-up. Of these, 185 completed PROMS follow-up at 2 years. There was significant improvement in HOOS (p&lt; 0.001) and OHS (p&lt; 0.001) and FJS (p&lt; 0.001) between the pre-operative and 2-year outcomes. Patients reported improved pain (p&lt;0.001), function (p&lt;0.001) and reduced stiffness (p&lt;0.001) as measured by the WOMAC score. Patients had improved activity scores on the UCLA Active Score (P&lt;0.001) with 53% reporting return to impact activity at 2 years. There was no osteolysis and the mean acetabular cup inclination angle was 41deg and the femoral component shaft angle was 137deg. No fractures were reported over but there was one sciatic nerve palsy with partial recovery. Two patients were revised; one at 3 months for pain due to a misdiagnosed back problem and another at 33 months for loosening of the acetabular component with delamination of the titanium ingrowth surface.CoC resurfacing at 2-years post-operation demonstrate promising results with satisfactory PROMS.

Assessment of Functional Outcomes of Femur Treatment Using Modified Thoresen’s Criteria in Terms of Malalignment, Knee Motion, and Associated Symptoms

Comminuted fracture shaft of femur is increasing day by day due to Severe violence by road traffic accident and fall from height in modern civilization and intramedullary nailing sometimes technically not feasible in this type of fracture (AO type-32B3, 32C). Reaming may aggravate the comminution and displaced the comminuted fragments and sometimes difficult in segmental fracture involving metaphyseal region. To assessment of functional outcomes of femur treatment using modified Thoresen’s Criteria in terms of malalignment, knee motion, and associated symptoms. The study was carried out at the Dhaka medical college Hospital over a period of one and half year from September, 2016 to February, 2018. The total number of patients were 24. The mean age of the patients was 33.1±9.9 and the lowest and highest ages were 20-60 years respectively. Age of most (58%) of the patients were below 30 years. Three quarter of the patients (75%) were male and 37.5% were day labourer. Most of the patients (81%) were presented with right sided comminuted femoral shaft fracture. All of the injuries were closed type. In terms of type of fracture, AO type 32C2 were predominant (50%).AO type 32B3, 32C1,32C3 were 12.5%, 12.5% and 25%. Associated injury was found 6 patients that was 25% among 24 patients. Total duration of surgery &lt;90 minute was taken in 41.5% and &gt;90 minutes taken in 58.5% with mean deviation was 105 minutes and standard deviation was 19 minutes. 16 patients (67%) exhibited wide range of knee motion (&gt;120), four (17%) patients slightly restricted knee motion (110-120), two patients (8%) moderately restricted knee motion (90-110) and two patients (8%) extremely restricted knee motion (&lt;90). Evaluation of outcome by The Modified Thoresen’s criteria (1985) 6 months after intervention demonstrated that 29% of the patients had excellent outcome, 57% good outcome, 9.5% fair and 4.5% poor outcome. Assessment of Functional Outcomes of Femur Treatment Using Modified Thoresen’s Criter

RISK OF PERIPROSTHETIC FRACTURE AFTER PRIMARY TOTAL HIP ARTHROPLASTY USING A COLLARED CEMENTLESS (CC) OR TAPER-SLIP CEMENTED STEM (PTS)

A: - determine the incidence of intraoperative periprosthetic femoral fracture (PFF)B: - determine the incidence of, and the reoperation rate for postoperative PFFWhen using either CC or PTS femoral components.Retrospective review of a consecutive series of 11,018 THAs over a ten-year period. All PFFs were identified using regional radiograph archiving and electronic care systems.Of the 11,018 THAs 4,952 were CC and 6,066 were PTS. Between groups, age, sex, and BMI did not differ.A: - 55 (0.5%) had an intraoperative PFF. 44 CC and 11 PTS (p&lt;0.001). 3 patients in each group had a femoral shaft fracture, remaining fractures were either the calcar (20 CC and 2 group) or the greater trochanter (11 CC and 6 PTS).B: - 91(0.8%) sustained a postoperative PFF. Of those 15 were managed conservatively, 15 were revised and 61 (80.3%) had an ORIF. The CC group had both a lower overall rate of postoperative PFFs (0.7% (36/4,952) vs 0.9% (55/6,066); p = 0.341), and a lower rate of return to theatre (0.4% (22/4,952) vs 0.9% (54/6,066); p = 0.005). 1.3% of male PTS (36/2,674) had a reoperation compared to 0.3% of male CC (7/2,121) (p&lt;0.001).With regard to stem fracture there were none in the Corail group and 5 in the Exeter group. Of these 2 were sub trunnion and 3 were basal neck.A: - There were significantly more intraoperative PFFs with CC 44 (0.8%) than PTS 11 (0.2%). However, the majority of fractures were either of the calcar or greater trochanter with no impact on early recovery or one year Oxford scores.B: - Male PTS were five times more likely to have a reoperation for postoperative PFF. Females had the same incidence of reoperation with either component type.There were 5 stem fractures in the Exeter group and none in the Corail.These results represent robust estimates, which are likely to be more accurate than revision only studies typically generated from registry data.

SHORTENING OSTEOTOMIES OF THE FEMUR DURING TOTAL HIP ARTHROPLASTY FOR DEVELOPMENTAL HIP DYSPLASIA

Total hip arthroplasty (THA) for congenital hip dysplasia (CDH) presents a challenge. In high-grade CDH, key surgical targets include cup placement in the anatomical position and leg length equality. Lengthening of more than 4 cm is associated with sciatic nerve injury, therefore shortening osteotomies are necessary. We present our experience of different shortening osteotomies including advantages and disadvantages of each technique.89 hips, in 61 pts (28 bilateral cases), for high CDH were performed by a single surgeon from 1997 to 2022. 67 patients were female and 22 were male. Age ranged from 38 to 68 yrs. In all patients 5–8cm of leg length discrepancy (LLD) was present, requiring shortening femoral osteotomy. 12 patients underwent sequential proximal femoral resection with trochanteric osteotomy, 46 subtrochanteric, 6 midshaft, and 25 distal femoral osteotomies with simultaneous valgus correction were performed. All acetabular prostheses were placed in the true anatomical position. We used uncemented high porosity cups. Patients were followed up for a minimum of 12 months.All osteotomies healed uneventfully except 3 non-unions of the greater trochanter in the proximal femur resection group. No femoral shaft fractures in proximally based osteotomies. No significant LLD compared to the unaffected or reconstructed side. 2 patients suffered 3 and 5 degrees malrotation of the femur in the oblique sub-trochanteric group. 3 patients suffered transient sciatic nerve palsies.Shortening femoral osteotomies in the treatment of DDH are necessary to avoid injury to the sciatic nerve. In our series, we found transverse subtrochanteric osteotomies to be the most technically efficient, versatile and predictable in their clinical outcome, due to the ability to correct rotation and preserve the metaphyseal bone integrity, allowing for better initial stem stability. Distal femoral osteotomies allowed for controllable correction of valgus knee deformity.

Does postoperative immobilization affect final alignment of pediatric femur fractures treated with flexible intramedullary nailing?

Flexible intramedullary nail (FIN) fixation of pediatric femur fractures is a popular method of fixation in children. Typical immobilization options include spica casting, long leg cast, knee immobilizers, or no immobilization and the decision to use each is usually left to surgeon preference. Our primary aim is to evaluate whether different postoperative immobilization status influences outcomes, namely radiographic alignment at the time of healing. A retrospective chart review was conducted of all patients with femur fractures treated with FIN fixation at a pediatric hospital from April 2018 through July 2022. Postoperative immobilization protocols were recorded and separated into two groups, patients who were immobilized (IMM) and patients who were not immobilized (NoIMM). Radiographs were evaluated for fracture alignment immediately following surgery and at the time of healing. Patients demographic, fracture, and postoperative clinical characteristics were compared between the two groups (NoIMM vs. IMM). A total of 41 patients were treated for diaphyseal femur fractures with FINs at our institution during the study period. No significant difference was observed in alignment at healing. Our results suggest that either immobilization or no immobilization after flexible intramedullary nailing of pediatric femoral shaft fractures are viable options when postoperative immobilization status is left to the surgeon's discretion.

Geriatric femur fractures: Index fracture pattern is associated with the risk of subsequent peri-implant fracture

IntroductionFollowing an index femoral fragility fracture, patients are at risk of a subsequent peri-implant fracture. Management of these injuries are further complicated by patient factors and multi-institutional care. This study quantifies such events and compare rate of identification between in-system and out-of-system patients. MethodsA retrospective chart review of index operative femoral fragility fractures at a level I trauma center from January 1, 2005 to January 1, 2018 identified 840 patients with twenty-two subsequent peri-implant fractures. Kaplan Meier survival analyses assessed associations between patient and injury characteristics with the subsequent fracture while accounting for differential follow-up. Cumulative incidence curves were reported, and Cox regression analyses estimated hazard ratios for statistically significant associations. In-system and out-of-system patients were compared with absolute rate of identifying subsequent fracture and follow-up time. ResultsCumulative incidence of subsequent fracture was 2.1 % at 2 years, 3.4 % at 4 years, and 4.6 % at 6 years. The index fracture pattern (intertrochanteric vs other) was associated with a cumulative incidence of subsequent peri-implant fracture (0.8 % at 2 years, 1.4 % at 4 years, and 2.7 % at 6 years for intertrochanteric fractures vs 3.4 % at 2 years, 5.3 % at 4 years, and 6.4 % at 6 years for non-intertrochanteric fractures), p = 0.029. Follow-up was shorter for out-of-system patients (median 6 versus 28 months, p < 0.001), and only 1 of 348 out-of-system patients (0.3 %) vs. 21 of 492 in-system patients (4.3 %) were diagnosed with a subsequent peri-implant fracture (p < 0.001). There was no association of subsequent peri-implant fracture with patient demographics or comorbidity burden. ConclusionCumulative incidence of subsequent peri-implant fracture was higher for non-intertrochanteric (femoral neck, shaft and distal femur) fractures than intertrochanteric fractures. Out-of-system patients had shorter follow-up and were less likely to be diagnosed with a subsequent peri-implant fracture, indicating ascertainment bias and underscoring the importance of accounting for loss to follow-up. Level of evidenceTherapeutic Level III.

Management of Femoral and Tibial Shaft Fractures in Chronic Spinal Cord Injury Patients.

To compare outcomes and complications between non-operative and operative management of femur and tibia fractures in patients with paraplegia or quadriplegia from chronic spinal cord injury (SCI). Design: Retrospective cohort study. Three Level-1 Trauma centers. All adult patients with paraplegia or quadriplegia due to a chronic SCI with operative or nonoperative treatment of a femoral or tibial shaft fracture from 01/01/2009 through 12/31/2019 were included. Outcomes collected included range of motion, pain, return to baseline activity, extent of malunion and treatment complications (infection, pressure ulcers, nonunion, DVT/PE, stroke, amputation, death). Comparison between operative and nonoperative treatment were made for each outcome. Fifty-nine patients with acute lower extremity fracture in the setting of chronic SCI fulfilled inclusion criteria with a median age of 46 years in the operative group and 47 years in the non-operative group. Twelve patients (70.6%) in the nonoperative group were male with 32 (76.2%) male patients in the operative group. Forty-six patients (78%) presented as low energy trauma. Differences were seen between operative and non-operative management for pressure ulcers (19% vs 52.9%, p=0.009) and mean VAS pain score at first follow-up (1.19 vs 3.3, p=0.03). No difference was seen for rates of infection, nonunion, DVT/PE, stroke, amputation, death, return to baseline activity, and range of motion. Tibial and femoral shaft fractures commonly resulted from low energy mechanisms in patients with chronic SCI. Operative treatment seemed to decrease morbidity in these patients via lowered rates of pressure ulcers and decreased pain compared to non-operative management. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Femora nutrient foramina and aerobic capacity in giant extinct xenarthrans.

Nutrient foramina are small openings in the periosteal surface of the mid-shaft region of long bones that traverse the cortical layer and reach the medullary cavity. They are important for the delivery of nutrients and oxygen to bone tissue and are crucial for the repair and remodeling of bones over time. The nutrient foramina in the femur's diaphysis are related to the energetic needs of the femur and have been shown to be related to the maximum metabolic rate (MMR) of taxa. Here, we investigate the relationship between nutrient foramen size and body mass as a proxy to the aerobic capacity of taxa in living and extinct xenarthrans, including living sloths, anteaters, and armadillos, as well as extinct xenarthrans such as glyptodonts, pampatheres, and ground sloths. Seventy femora were sampled, including 20 from extant taxa and 50 from extinct taxa. We obtained the blood flow rate (Q̇) based on foramina area and performed PGLS and phylogenetic ANCOVA in order to explore differences among mammalian groups. Our results show that, among mammals, taxa commonly associated with lower metabolism like living xenarthrans showed relatively smaller foramina, while the foramina of giant extinct xenarthrans like ground sloths and glyptodonts overlapped with non-xenarthran placentals. Consequently, Q̇ estimations indicated aerobic capacities comparable to other placental giant taxa like elephants or some ungulates. Furthermore, the estimation of the MMR for fossil giant taxa showed similar results, with almost all taxa showing high values except for those for which strong semi-arboreal or fossorial habits have been proposed. Moreover, the results are compatible with the diets predicted for extinct taxa, which indicate a strong consumption of grass similar to ungulates and in contrast to the folivorous or insectivorous diets of extant xenarthrans. The ancestral reconstruction of the MMR values indicated a lack of a common pattern for all xenarthrans, strongly supporting the occurrence of low metabolic rates in extant forms due to their particular dietary preferences and arboreal or fossorial habits. Our results highlight the importance of considering different evidence beyond the phylogenetic position of extinct taxa, especially when extinct forms are exceptionally different from their extant relatives. Future studies evaluating the energetic needs of giant extinct xenarthrans should not assume lower metabolic rates for these extinct animals based solely on their phylogenetic position and the observations on their extant relatives.

Analysis of the influence of circumference and displacement of the third fracture fragment on the healing of femoral shaft fractures treated with intramedullary nailing

The effect of circumference and displacement of the third fracture fragment on fracture healing after intramedullary nailing of femoral shaft fractures with a third fracture fragment was investigated. A retrospective cohort study was conducted to analyze the data of 142 patients who suffered femoral shaft fractures with a third fracture fragment and were admitted to the First People’s Hospital of Lianyungang from February 2016 to December 2021. According to the circumference of the third fracture fragments, these were divided into three types of type 1: 71 cases; type 2: 52 cases; and type 3: 19 cases. On the basis of the diaphyseal diameter, the degree of displacement of the third fracture fragment was classified into three degrees of degree I: 95 cases; degree II: 31 cases; and degree III: 16 cases. Postoperative follow-up was performed to compare the fracture healing rate, healing time, and the modified Radiographic Union Scale for Tibia (mRUST) at 9th month after surgery in each group. All 142 patients were followed up after operation, with an average of (14.7 ± 4.1) months, and the overall healing rate was 73.4%. When the third fracture fragments were displaced in degree II and III, the mRUST score at 9th month in the type 1 group was higher than that in the type 2 and 3 groups (P = 0.017). Logistic regression analysis showed that greater displacement of third fracture fragments and greater circumference were associated with lower fracture healing rates (P < 0.05). After intramedullary nailing of femoral fractures, the degree of third fragment displacement and circumference affect fracture healing, and the former has a greater impact. When the third fracture fragment is displaced to degree II or III and its circumference is type 2 or type 3, it significantly affects the fracture healing. Intraoperative intervention to reduce the distance of third displacement of the fragment is required to reduce the incidence of non-union.

Three-dimensional-printed femoral diaphysis for biomechanical testing-Optimization and validation.

Polylactic acid (PLA) models of normal human femoral diaphyses were designed using three-dimensional (3D) printing technology to create inexpensive, accessible, and reproducible specimens for flexural biomechanical studies. These models were subjected to three-point bending and their response to loading was characterized. The anisotropic mechanical behavior of the 3D-printed femurs and the influence of printing orientations, infill density, wall layers, resolution, and other printing parameters were explored to develop a design space. The objective of the design space was set to emulate the flexural biomechanical response of the normal human femur bones. Results show the 3D-printed PLA diaphyseal femurs with 5% infill density, two-four wall layers, and a resolution of 200 µm resulted in a flexural strength of 184.8 ± 8.18 MPa. Models with 20% infill density and six wall layers resulted in a flexural modulus of 18.54 ± 0.543 GPa. These results emulate the biomechanical response of the normal human femur, as determined by historical target values derived from prior cadaveric and 3D printing data. With further research, inclusive of modeling the proximal and distal femur and more comprehensive biomechanical testing, 3D-printed femurs may ultimately serve as a cheap, accessible biomechanical resource for surgeons and researchers.

Ultrasound-guided techniques for managing length- unstable femoral shaft fractures in children

ObjectiveThe management of length-unstable femoral shaft fractures(LUFSFs) in pediatric patients is still controversial. This study aims to explore the clinical efficacy of ultrasound-guided closed reduction combined with external fixation for treating LUFSFs in children.MethodsWe conducted a retrospective analysis of clinical data from 19 pediatric patients with LUFSFs who underwent ultrasound-guided closed reduction and external fixation between January 2018 and January 2023. Ultrasound was employed not only to facilitate closed reduction of the fracture but also to guide real-time insertion of Schanz pins and monitor pin length as it traversed the opposite cortex. Surgical time, intraoperative fluoroscopy count, hospital stay length, fracture fixation duration, complication incidence, fracture reduction quality at the final follow-up were recorded.ResultsThe patients’ average age was 7.5 years( range: 5 to 11 years). The mean surgical duration was 70.4 min (range: 48–105 min), and the average intraoperative fluoroscopy count was 6.5 (range: 2–16). Fracture fixation lasted an average of 10.9 weeks (range: 7–20 weeks). All patients were followed up for more than one year. 6 cases of superficial pin tract infection occurred, which resolved with oral antibiotics and enhanced needle tract care. No deep infections were observed. Temporary stiffness of the knee joint was observed in 2 patients. According to Flynn’s efficacy evaluation system, fracture reduction quality at the final follow-up was rated as excellent in 11 cases and satisfactory in 8 cases, yielding a combined success rate of 100% (19/19).ConclusionsThe technique of ultrasound-guided closed reduction combined with external fixation offers favorable outcomes for children aged 5 to 11 years with LUFSFs, reducing reliance on fluoroscopic guidance.