Analysis of risk factor for nail breakage in patients with mechanical failures after proximal femoral nail antirotation in intertrochanteric fractures

Breakage of the intramedullary nail is a rare complication after proximal femoral nail antirotation (PFNA) in intertrochanteric fracture treatment. The purpose of this study was (1) to investigate the frequency of nail breakage among the patients who were treated for mechanical failure after PFNA for intertrochanteric/pertrochanteric fracture, and (2) to determine the risk factors for nail breakage in PFNA treatment of intertrochanteric fracture.To identify mechanical failure after internal fixation using PFNA, we retrospectively reviewed the data of 35 patients (35 hips) who required reoperation after PFNA with a helical blade for intertrochanteric/pertrochanteric fracture between June 2005 and June 2018.We evaluated the frequency of breakage of PFNA and compared the demographic and radiologic parameters between the breakage and control (non-breakage) groups. We also compared the lever arm for the load of stress from the fulcrum according to the centrum-collum-diaphyseal (CCD) angle of blade by using reverse design technique.Among the 25 patients with mechanical failure after PFNA except 10 patients with peri-implant infection and osteonecrosis, 7 (28.0%) showed breakage of PFNA at average of 8 months (range, 5-13 months) after index surgery. A larger horizontal offset (the horizontal distance from the lateral surface of the IM nail and the medial tip of helical blade) was associated with an increased risk of nail breakage. A CCD angle of 130° has a shorter lever arm for the load of stress from the fulcrum, meaning a higher stress for nail breakage, although there was no association between CCD angle and breakage of the nail.Our study suggested that higher horizontal offset and a higher CCD angle can increase the risk of breakage of the PFNA nail at the aperture for the helical blade.

The Relationship Between Lesion Size and Load to Failure After Stabilization of Simulated Metastatic Lesions of the Proximal Femur

BACKGROUND

As overall cancer survival continues to improve, the incidence of metastatic lesions to the bone continues to increase. The subsequent skeletal related events that can occur with osseous metastasis can be debilitating. Complete and impending pathologic femur fractures are common with patients often requiring operative fixation. However, the efficacy of an intramedullary nail construct, on providing stability, continue to be debated. Therefore, the purpose of this study was to utilize a synthetic femur model to determine 1) how proximal femur defect size and cortical breach impact femur load to failure (strength) and stiffness, and 2) and how the utilization of an IMN, in a prophylactic fashion, subsequently alters the overall strength and stiffness of the proximal femur.

METHODS

A total of 21 synthetic femur models were divided into four groups: 1) intact (no defect), 2) 2 cm defect, 3) 2.5 cm defect, and 4) 4 cm defect. An IMN was inserted in half of the femur specimens that had a defect present. This procedure was performed using standard antegrade technique. Specimens were mechanically tested in offset torsion. Force-displacement curves were utilized to determine each constructs load to failure and overall torsional stiffness. The ultimate load to failure and construct stiffness of the synthetic femurs with defects were compared to the intact synthetic femur, while the femurs with the placement of the IMN were directly compared to the synthetic femurs with matching defect size.

RESULTS

The size of the defect invertedly correlated with the load the failure and overall stiffness. There was no difference in load to failure or overall stiffness when comparing intact models with no defect and the 2 cm defect group (p=0.98, p=0.43). The 2.5 cm, and 4.5 cm defect groups demonstrated significant difference in both load to failure and overall stiffness when compared to intact models with results demonstrating 1313 N (95% CI: 874-1752 N; p<0.001) and 104 N/mm (95% CI: 98-110 N/mm; p=0.03) in the 2.5 cm defect models, and 512 N (95% CI: 390-634 N, p<0.001) and 21 N/mm (95% CI: 9-33 N/mm, p<0.001) in the models with a 4 cm defect. Compared to the groups with defects, the placement an IMN increased overall stiffness in the 2.5 cm defect group (125 N/mm; 95% CI:114-136 N/mm; p=0.003), but not load to failure (p=0.91). In the 4 cm defect group, there was a significant increase in load to failure (1067 N; 95% CI: 835-1300 N; p=0.002) and overall stiffness (57 N/mm; 95% CI:46-69 N/mm; p=0.001).

CONCLUSION

Prophylactic IMN fixation significantly improved failure load and overall stiffness in the group with the largest cortical defects, but still demonstrated a failure loads less than 50% of the intact model. This investigation suggests that a cortical breach causes a loss of strength that is not completely restored by intramedullary fixation. Level of Evidence: II.

[ROAD CYCLING, DECREASED BONE DENSITY AND PROXIMAL FEMORAL FRACTURES]

INTRODUCTION

Cycling in Israel: Cycling in Israel is a common sport which is considered to be beneficial to health. However, questions arise about its impact on bone health, due to publications reporting a decrease in bone density in cyclists and the presence of fractures that characterize a relatively older population in relatively young cyclists. Exercise and bone health: It has been proven that a sporty lifestyle, exercise in general and cycling in particular, lowers the chance of fractures of the proximal femur. Cycling and bone density: Several studies have shown that cycling regularly, particularly road cycling, without a combination of off-road cycling/ running/ impact exercise, leads to a decrease in bone density especially in the hip area. The phenomenon is seen at all ages (adolescents and adults), in women and men. Improving bone density values: The only options that have been shown to increase bone density are the combination of impact exercise such as running, off-road cycling, etc. or adding whole-body vibration training to the training routine.

DISCUSSION

Despite the common assumption that sports activities contribute to bone health, and therefore to a reduced risk of fractures, a review of the medical literature shows that paradoxically, road cycling has a negative effect on bone strength, and therefore is a risk factor for proximal femoral fractures. To avoid this, we recommend incorporating in the training routine: running/ off-road cycling/ impact exercise/ whole body vibration. It is also important to maintain a balanced diet, while sustaining adequate calcium intake.

The characteristics and influence of iatrogenic fracture comminution following antegrade interlocking nailing for simple femoral shaft fractures, a retrospective cohort study

AIM

The incidence and characteristics of iatrogenic comminution (IC) are unknown, and the influence of IC on fracture union is unclear. This study was aimed to investigate the (1) incidence and characteristics of IC and (2) the outcomes of IC following antegrade interlocking nailing of simple femoral shaft fractures.

METHODS

We retrospectively collected data on patients who experienced simple femoral shaft fractures and underwent antegrade interlocking nailing between February 2009 and December 2016. The incidence and characteristics of IC were examined. According to the presence of IC, patients were divided into two groups: an IC group and a non-IC (NIC) group. Demographic information and nonunion rates were compared between the two groups. Potential risk factors for IC (age, gender, body mass index (BMI), nail fit ratio, reduction technique, and greater trochanter nail entry) were analyzed using univariate and multivariate logistic regression. The aforementioned variables, along with IC occurrence, were also assessed as potential risk factors for nonunion at 12 and 24 months after operation using multivariate logistic regression.

RESULTS

Of the 211 total patients, IC occurred in 20.9% (n = 44) of patients. Most ICs were found at the level of the isthmus, and involved the medial cortex. Compared with the NIC group, higher nonunion rates were observed in the IC group at 12 months (31.8% vs. 12.5%, p = 0.002) and 24 months (18% vs. 6.5%, p = 0.017) after surgery. Age older than 35 years old was related with the occurrence of IC in univariate analysis. Multivariate analysis found no risk factor associated with IC. Open reduction technique, IC occurrence and higher BMI were identified as the risk factors of nonunion at 12 months and 24 months after surgery in multivariate analysis.

CONCLUSION

IC is a non-rare complication in antegrade interlocking nailing of simple femoral shaft fractures and was associated with higher nonunion rate. Age older than 35 years old showed a trend toward increasing risk of iatrogenic fracture comminution. In multivariate analysis, open reduction technique, IC occurrence and higher BMI significantly correlated with fracture nonunion.

LEVEL OF EVIDENCE

Level IV.

Expandable Proximal Femoral Nail versus Gamma Proximal Femoral Nail for the treatment of hip reverse oblique fractures

BACKGROUND

Reverse oblique intertrochanteric fractures are classified by the AO/OTA as 31A3 and account for 2-23% of all trochanteric fractures. The Gamma 3-Proximal Femoral Nail (GPFN) and the Expendable Proximal Femoral Nail (EPFN) are among the various devises used to treat this fracture. The aim of this study was to compare outcomes and complication rates in patients with AO/OTA 31A1-3 fractures, treated by either a GPFN or an EPFN.

PATIENTS AND METHODS

A total of 67 patients (40 in the GPFN group and 27 in the EPFN group, average age 78.8 years) were treated in our institution between July 2008 and February 2016. Data on postoperative radiological variables, including peg location and tip-apex distance (TAD), as well as orthopedic complications, such as union rate, surgical wound infection and cut-outs rates were also recorded, along with the incidence of non-orthopedic complications and more surgical data. Functional results were evaluated and quantified using the Modified Harris Hip Score (MHHS) and by the Short Form 12 Mental Health Composite questionnaire (SF-12 MHC) in order to assess the quality of life.

RESULTS

The total prevalence of postoperative orthopedic complications including postoperative infection showed a significant difference with a p-value of 0.016 in favor of the EPFN group. Nonetheless, the frequency of revision did not differ between the two groups, being 0.134. The main orthopedic complication in both groups was head cut-out of the GPFN lag screw and the EPFN expendable peg, which was 20% and 7.4%, respectively, and required a revision surgery using a long nail or total hip replacement (THR). However, the average TAD did not significantly differ between groups which might be due to a relatively low cohort to reach a significant difference. Nonunion rate of 5% occurred solely in the GPFN group, with similar results of intraoperative open reduction between both groups. The EPFN group achieved better scores in both questionnaires (p = 0.027 and p = 0.046, respectively). Both the MHHS and SF-12 MCS values significantly differed between groups, with the EPFN group achieving better scores than the GPFN group in both questionnaires (p = 0.027 and p < 0.05, respectively).

CONCLUSIONS

According to this study, the EPFN yields better results in comparison with the GPFN, with relatively less complications rate, for the treatment of unstable reverse oblique pertrochanteric fracture. In light of this results, we conclude that the EPFN might be as good as GPFN for the treatment of reverse oblique intertrochanteric fractures.

LEVEL OF EVIDENCE

Level III retrospective study. The local institutional review board of the Tel Aviv Medical Center approved this study and all the surgeries were done exclusively in this institution.

New Classification for Periprosthetic Distal Femoral Fractures Based on Locked-Plate Fixation Following Total Knee Arthroplasty: A Multicenter Study

BACKGROUND

This study aimed to establish a new classification using locked-plate fixation for periprosthetic distal femoral fracture (PDFF) following total knee arthroplasty (TKA) and to determine when dual locked-plate fixation is necessary through defining this classification.

METHODS

One-hundred fifteen consecutive PDFFs that underwent operative treatment were reviewed from 2011 to 2019 with minimum 1-year follow-up. Most PDFFs were fixed with single or dual locked-plate fixations using the minimally invasive plate osteosynthesis technique. Based on preoperative radiographs, PDFFs were classified according to the level of main fracture line relative to the anterior flange of femoral component: type I and II, main fracture line located proximal and distal to the anterior flange; and type III, component instability regardless of fracture line requiring revisional TKA. Furthermore, type II fractures were subclassified based on the direction of fracture beak as follows: type II_L, lateral-beak; type II_M, medial-beak. The incidence, treatment methods, and complications were analyzed according to the classification.

RESULTS

Incidences of type I, II_L, II_M, and III were 64.4%, 8.7%, 24.3%, and 2.6%, respectively. Meanwhile, most PDFFs in type I and II were treated with lateral single locked-plate fixations, except for type II_M, which was treated with either single or dual locked-plate fixations. Overall complications were significantly higher in type II (28.9%) than in type I (10.8%, P = .019). In type II_M, bone union-related complications were significantly higher in single locked-plate fixation (50.0%) than in dual locked-plate fixation (5.6%; P = .013).

CONCLUSION

The new classification provides practical and obvious strategies for the treatment of PDFF following TKA using locked-plate fixation. For type II_M fracture, dual plate fixation is necessary to prevent fixation failure or nonunion.

Elastic Intramedullary Nails in the Treatment of Pediatric Length Unstable Femur Fractures

BACKGROUND

Elastic intramedullary nails (EINs) are the treatment of choice for school-age children (5 to 12) with diaphyseal femur fractures. Previous literature suggests that EINs are an effective treatment for stable fracture patterns, but may be inadequate for unstable fracture patterns. The purpose of this study was to evaluate whether patients with length unstable fractures had a higher complication rate than those with length stable fractures when treated with EINs.

METHODS

All patients with diaphyseal femur fractures treated with EINs over a 22-year period at a single institution were reviewed. Patients were excluded if they had a pathologic fracture, neuromuscular disorder, spinal cord injury with subsequent involvement of affected limb, metabolic bone disease, or if they did not have at least 6-month follow-up.

RESULTS

A total of 85 patients with 87 diaphyseal femur fractures treated with EINs were included in the study. In all, 57.5% of the fractures were categorized as length stable and 42.5% were length unstable. Fourteen percent of length stable patients had a residual angular deformity compared with 5.4% of the length unstable group (P=0.24). The length unstable group experienced more shortening at the fracture site than the patients in the length stable group (P=0.003), but no patient required further intervention for their shortening. Two patients in the length stable group experienced overgrowth >2 cm and required subsequent surgery. No relationship was observed between fracture pattern and frequency of complications (length stable 8% vs. length unstable 10.8%, P=0.69). Finally, the knee immobilizer group (10.7%) and the long leg cast group (18.2%) had significantly higher complication rates than the single leg spica cast group (0%, P<0.05).

CONCLUSIONS

There was no significant difference in complication rate between length stable and unstable fractures treated with EINs. Adjunctive spica casting may be protective against postoperative complications. While fracture shortening was more likely in the length unstable group, it did not result in increased rate of limb length discrepancy at final follow-up.

LEVEL OF EVIDENCE

Level IV, Case Series.

Subtrochanteric Insufficiency Fracture Occurring 5 Years after Surgery at the Steinmann Pin Insertion Site for Fracture Reduction

Background and Objectives: Steinmann pins are commonly used in orthopedics, with a low rate of complications. However, thermal osteonecrosis may occur when a pin is inserted using a drill. There have been no reports on late-onset fractures at the Steinmann pin insertion site. Materials and Methods: A 32-year-old man who underwent surgery for a femoral shaft fracture 5 years ago complained of proximal thigh pain 1 month after the removal of the internal device. On physical examination, the patient showed a limping gait due to pain, and tenderness was observed on the lateral aspect of the proximal thigh. Magnetic resonance imaging was performed because the symptoms did not improve, despite conservative treatment. A new fracture line was observed in the lateral cortical bone of the proximal femur. It was found that a fracture occurred at the site where the Steinmann pin was inserted for a closed reduction at the time of the first operation. The patient was instructed to limit weight bearing and to use crutches while walking. Parathyroid hormone was additionally administered to promote bone formation. Results: Six months after diagnosis, a complete union was achieved at the subtrochanteric fracture site, and the patient’s pain subsided. Conclusions: A fracture that occurs as a late onset at the provisional Steinmann pin insertion site is an extremely rare complication; however, orthopedic surgeons must consider this possibility and make more efforts to lower the occurrence of thermal damage. In addition, if the patient complains of pain in the region where the pin was inserted after surgery, surgeons should spare no effort to determine whether a new fracture has occurred.

Clinical and radiographical outcome after surgical treatment of periprosthetic type B proximal femur fractures: a retrospective study

PURPOSE

Periprosthetic fractures after hip prosthesis represent a constantly increasing clinical problem and a challenging complication to treat surgically. Among these, type B proximal femur fractures should be diagnosed correctly to be treated surgically. The aim of this study was to re-evaluate the type of surgical treatment of periprosthetic fractures.

METHODS

We examined the cases treated between January 2012 and February 2018, classifying them according to the U.C.S. AO/OTA. We evaluated the radiographic outcome according to the Beals and Tower criteria. Patients still alive were also re-evaluated according to the H.H.S. and the WOMAC score.

RESULTS

We treated 48 patients (12 men, 35 women, average age 81 years), divided into 24 type B1, 14 type B2 and 10 type B3 fractures. The overall consolidation rate was 95.4%, while the major complication (implant dislocation, pseudoarthrosis and deep infection) rate was 12.5%. Clinically, it was possible to reassess 34 patients with a mean follow-up of 38.4 months, an average HHS of 75.89 and a mean WOMAC score of 79.93.

CONCLUSIONS

Periprosthetic type B fractures are difficult to manage and require careful preoperative planning and appropriate intraoperative management. However, the overall clinical and radiographic result was satisfactory, although patients should still be aware of the risk of complications associated with this type of fracture.

Periprosthetic Supracondylar Femoral Fractures Above a Total Knee Replacement: An Updated Compatibility and Technique Guide for Fixation With a Retrograde Intramedullary Nail

BACKGROUND

Multiple studies have described retrograde nailing as a treatment of periprosthetic supracondylar femoral fractures (OTA/AO type 33A-C) above total knee replacements (TKRs). It is often difficult to discern which TKRs will be compatible with intramedullary nailing because the femoral component design and intercondylar distance is highly variable among total knee designs. The goal of our study is 3-fold: (1) Review and update previous work of intercondylar distances of all currently available prostheses in the United States. (2) Review retrograde nails currently on the market and associated driving end to nail shaft diameter mismatch and opening reamer sizing. (3) Review technical tricks for executing a retrograde femoral nail for the treatment of periprosthetic supracondylar femur fractures.

METHODS

Data for the intercondylar distance of the femoral components, diameter of retrograde nails and reamers, and notch compatibility were gathered.

RESULTS

The results were compiled and recorded. A "technical tricks" section was included that highlights reduction and fixation techniques.

CONCLUSIONS

This update further empowers surgeons to use all the tools available when treating periprosthetic femur fractures and allows efficient identification of the compatibility of different TKR designs with various intramedullary nails.

LEVEL OF EVIDENCE

Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.

Gene Network of Susceptibility to Atypical Femoral Fractures Related to Bisphosphonate Treatment

Atypical femoral fractures (AFF) are rare fragility fractures in the subtrocantheric or diaphysis femoral region associated with long-term bisphosphonate (BP) treatment. The etiology of AFF is still unclear even though a genetic basis is suggested. We performed whole exome sequencing (WES) analysis of 12 patients receiving BPs for at least 5 years who sustained AFFs and 4 controls, also long-term treated with BPs but without any fracture. After filtration and prioritization of rare variants predicted to be damaging and present in genes shared among at least two patients, a total of 272 variants in 132 genes were identified. Twelve of these genes were known to be involved in bone metabolism and/or AFF, highlighting DAAM2 and LRP5, both involved in the Wnt pathway, as the most representative. Afterwards, we intersected all mutated genes with a list of 34 genes obtained from a previous study of three sisters with BP-related AFF, identifying nine genes. One of these (MEX3D) harbored damaging variants in two AFF patients from the present study and one shared among the three sisters. Gene interaction analysis using the AFFNET web suggested a complex network among bone-related genes as well as with other mutated genes. BinGO biological function analysis highlighted cytoskeleton and cilium organization. In conclusion, several genes and their interactions could provide genetic susceptibility to AFF, that along with BPs treatment and in some cases with glucocorticoids may trigger this so feared complication.

Femoral fracture during breech vaginal delivery: A case report

Femoral fracture is a rare but significant foetal injury, more frequent and likely to happen when the foetus is malpositioned or in a breech presentation. Cesarian section does not appear to be protective and all recent publications report cases occurring during cesarian section. We report a case that occurred in a vaginal delivery of a single footling breech presentation. This complication allows us to remind that femur fracture is a complication of breech delivery whatever the modality. The prognosis is good with early diagnosis.

Prophylactic Cerclage Cabling Decreases the Intraoperative Periprosthetic Fracture Rate during Cement-Less Total Hip Arthroplasty in Patients with Severe Developmental Hip Dysplasia

PURPOSE OF THE STUDY Cementless stems in highly dysplastic hips are considered to increase the risk of femoral fracture and associated morbidity. Several authors speculated to use prophylactic cabling in this patient group to prevent intraoperative fractures. This study aims to reveal objective results regarding the perioperative complications in a large and consecutive patient group with respect to use of prophylactic cabling. MATERIAL AND METHODS A retrospective comparative study was planned. A total of 122 consecutive patients with dysplastic hips of Crowe type 3 or 4, operated on with total hip arthroplasty (THA) and shortening osteotomy using a rectangular femoral stem were included. Patients were stratified according to use of a diaphyseal prophylactic cerclage cable. Perioperative complications were recorded. Clinical outcome was measured in terms of Harris Hip Score and Visual Analog Scale (VAS) for pain. All results were compared between the groups. RESULTS The mean follow-up time was 27 months. Two (2%) versus five (14%) patients had a fracture at the diaphyseal level in cabled versus non-cabled groups. Difference between groups was statistically significant (p=0.01). Relative risk of fracture in case of a non-cabling was 5.8 (p=0.03). Eleven (9%) patients had a non-displaced fracture at the metaphyseal level. No significant differences were detected with respect to preoperative clinical outcome scores or change in these scores between groups. CONCLUSIONS Femoral diaphyseal fracture rates are low when cementless, rectangular stems are used in dysplastic high riding hips. Prophylactic cerclage cabling further decreases the fracture risk and eases treatment in case of a fracture without causing additional complications and therefore is recommended. Key words: intraoperative fracture, periprosthetic fracture, total hip arthroplasty, cerclage cabling, developmental hip dysplasia, transverse shortening osteotomy.

Systemic effects of BMP2 treatment of fractures on non-injured skeletal sites during spaceflight

Unloading associated with spaceflight results in bone loss and increased fracture risk. Bone morphogenetic protein 2 (BMP2) is known to enhance bone formation, in part, through molecular pathways associated with mechanical loading; however, the effects of BMP2 during spaceflight remain unclear. Here, we investigated the systemic effects of BMP2 on mice sustaining a femoral fracture followed by housing in spaceflight (International Space Station or ISS) or on Earth. We hypothesized that in spaceflight, the systemic effects of BMP2 on weight-bearing bones would be blunted compared to that observed on Earth. Nine-week-old male mice were divided into four groups: 1) Saline+Earth; 2) BMP+Earth; 3) Saline+ISS; and 4) BMP+ISS (n = 10 mice/group, but only n = 5 mice/group were reserved for micro-computed tomography analyses). All mice underwent femoral defect surgery and were followed for approximately 4 weeks. We found a significant reduction in trabecular separation within the lumbar vertebrae after administering BMP2 at the fracture site of mice housed on Earth. In contrast, BMP2 treatment led to a significant increase in trabecular separation concomitant with a reduction in trabecular number within spaceflown tibiae. Although these and other lines of evidence support our hypothesis, the small sample size associated with rodent spaceflight studies limits interpretations. That said, it appears that a locally applied single dose of BMP2 at the femoral fracture site can have a systemic impact on distant bones, affecting bone quantity in several skeletal sites. Moreover, our results suggest that BMP2 treatment works through a pathway involving mechanical loading in which the best outcomes during its treatment on Earth occurred in the weight-bearing bones and in spaceflight occurred in bones subjected to higher muscle contraction.

Multidisciplinary management of solitary hypervascular metastatic recurrence of renal cell carcinoma presenting with pathological femoral fracture

Renal cell carcinoma (RCC) frequently presents with osseous metastasis, predominantly lytic and prone to pathological fracture. The metastatic lesion in the extremity presents with local swelling, pain and immobility due to pathological fracture. The solitary or oligometastatic lesions should be treated with curative intent, which can help the patient to lead a more prolonged and disability-free life. The RCCs and their metastases are hypervascular with an exuberant arterial supply. Surgery can lead to uncontrolled life-threatening haemorrhage. Preoperative transarterial embolisation reduces tumour vascularity significantly and reduces intraoperative blood loss. We present a 46-year-old male patient with solitary hypervascular metastatic recurrence of RCC with a pathological femoral fracture with an infeasible initial surgery due to profuse haemorrhage. He was successfully treated by preoperative transarterial embolisation, followed by surgical resection and implantation of a megaprosthesis. Multidisciplinary management reduces patient morbidity and mortality with successful treatment in solitary hypervascular metastasis from RCC.

A cautionary case: osteoporotic femur fracture after robotic-assisted total knee arthroplasty

Osteoporosis is a disease of low bone mass which leads to an increased risk of fracture. The prevalence of osteoporosis is greatest amongst postmenopausal women who also form a large portion of patients with osteoarthritis presenting for total knee arthroplasty. We present a case of a 77-year-old female with knee osteoarthritis and osteoporosis on denosumab who underwent robotic-assisted total knee arthroplasty. Postoperatively, she suffered an atraumatic midshaft femur fracture at the pin site associated with the use of intraoperative robotic technology. This is a unique complication related to the use of robotics which requires additional skeletal fixation versus standard arthroplasty surgical technique. We recommend caution and further study regarding the use of robotics in total knee arthroplasty in the setting of osteoporosis and denosumab use.

Arthroscopic removal of an intra-articular screw causing joint impingement after distal femoral fracture repair in a dog

The use of lag screws to treat femoral condyle fractures is common, and their placement in surgery is technically demanding. Intra-articular screw impingement is a serious complication that may occur during surgical treatment of femoral condyle fractures. Here, we describe the case of a 3-year-old 40-kg dog which experienced recurrent lameness 6 mo after successful surgical treatment of a comminuted medial femoral condyle fracture due to an intra-articular non-loosening screw causing joint impingement. Removal of the conflicting screw was performed arthroscopically, based on its ability to offer minimally invasive access to the stifle joint. Six months after removal of the screw, the dog had full recovery without limitations to range of motion or stifle pain. To our knowledge, this is the first report on the use of arthroscopy to remove an intra-articular screw causing joint impingement after distal femoral fracture repair in a dog.

Free Transplantation of a Tissue Engineered Bone Graft into an Irradiated, Critical-Size Femoral Defect in Rats

Healing of large bone defects remains a challenge in reconstructive surgery, especially with impaired healing potential due to severe trauma, infection or irradiation. In vivo studies are often performed in healthy animals, which might not accurately reflect the situation in clinical cases. In the present study, we successfully combined a critical-sized femoral defect model with an ionizing radiation protocol in rats. To support bone healing, tissue-engineered constructs were transferred into the defect after ectopic preossification and prevascularization. The combination of SiHA, MSCs and BMP-2 resulted in the significant ectopic formation of bone tissue, which can easily be transferred by means of our custom-made titanium chamber. Implanted osteogenic MSCs survived in vivo for a total of 18 weeks. The use of SiHA alone did not lead to bone formation after ectopic implantation. Analysis of gene expression showed early osteoblast differentiation and a hypoxic and inflammatory environment in implanted constructs. Irradiation led to impaired bone healing, decreased vascularization and lower short-term survival of implanted cells. We conclude that our model is highly valuable for the investigation of bone healing and tissue engineering in pre-damaged tissue and that healing of bone defects can be substantially supported by combining SiHA, MSCs and BMP-2.

Deficiency of Omentin-1 leads to delayed fracture healing through excessive inflammation and reduced CD31hiEmcnhi vessels

Fracture healing is a complicated process affected by many factors, such as inflammatory responses and angiogenesis. Omentin-1 is an adipokine with anti-inflammatory properties, but whether omentin-1 affects the fracture healing process is still unknown. Here, by using global omentin-1 knockout (omentin-1^-/-) mice, we demonstrated that omentin-1 deficiency resulted in delayed fracture healing in mice, accompanied by increased inflammation and osteoclast formation, and decreased production of platelet-derived growth factor-BB (PDGF-BB) and osteogenesis-promoting vessels that are strongly positive for CD31 and Endomucin (CD31^hiEmcn^hi) in the fracture area. In vitro, omentin-1 treatment suppressed the ability of the tumor necrosis factor-α (TNF-α)-activated macrophages to stimulate multi-nuclear osteoclast formation, resulting in a significant increase in the generation of mono-nuclear preosteoclasts and PDGF-BB, a pro-angiogenic protein that is abundantly secreted by preosteoclasts. PDGF-BB significantly augmented endothelial cell proliferation, tube formation and migration, whereas direct treatment with omentin-1 did not induce obvious effects on angiogenesis activities of endothelial cells. Our study suggests a positive role of omentin-1 in fracture healing, which may be associated with the inhibition of inflammation and stimulation of preosteoclast PDGF-BB-mediated promotion of CD31^hiEmcn^hi vessel formation.

Revision Arthroplasty Versus Open Reduction and Internal Fixation of Vancouver Type-B2 and B3 Periprosthetic Femoral Fractures

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Revision arthroplasty (RA) continues to be considered the gold standard in the surgical treatment of Vancouver type-B2 and B3 periprosthetic femoral fractures. However, open reduction and internal fixation (ORIF) has been associated with satisfactory outcomes. Thus, there is an ongoing discussion regarding the optimal surgical strategy for the treatment of these fractures.

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In this systematic review and meta-analysis, no significant differences in clinical and radiographic outcome were observed between ORIF and RA in the treatment of Vancouver type-B2 periprosthetic femoral fractures.

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ORIF of Vancouver type-B3 periprosthetic femoral fractures was associated with higher revision and reoperation rates than those after RA.

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Compared with RA, a significantly higher rate of subsidence was found in the ORIF group in Vancouver type-B2 periprosthetic femoral fractures whereas no significant difference in terms of loosening was observed.

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In the comparison of RA and ORIF for the treatment of Vancouver type-B2 and B3 fractures, the percentage of patients achieving full weight-bearing did not differ significantly.

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Mortality rates did not differ between RA and ORIF in the treatment of Vancouver type-B2 and B3 fractures.

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Overall complication rates did not differ between RA and ORIF in the treatment of Vancouver type-B2 and B3 fractures.

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We found a high heterogeneity in applied surgical and fixation techniques in the ORIF group.

Prediction of Long Bone Fractures in Multiple Myeloma Patients in an Advanced Imaging World

BACKGROUND

Multiple myeloma (MM) affects the long bones in 25% of patients. The advent of positron-emission tomography/computed tomography (PET/CT) scanners offers the possibility of both metabolic and radiographic information and may help determine fracture risk. To the best of our knowledge, no published study correlates these two factors with long bone fractures.

OBJECTIVES

To evaluate the impact of PET/CT on fracture risk assessment in multiple myeloma patients.

METHODS

We identified all bone marrow biopsy proven multiple myeloma patients from 1 January 2010 to 31 January 2015 at a single institution. We prospectively followed patients with long bone lesions using PET/CT scan images.

RESULTS

We identified 119 patients (59 males/60 females) with 256 long bone lesions. Mean age at diagnosis was 58 years. The majority of lesions were in the femur (n=150, 59%) and humerus (n=84, 33%); 13 lesions in 10 patients (8%) required surgery for impending (n=4) or actual fracture (n=9). Higher median SUVmax was measured for those with cortical involvement (8.05, range 0-50.8) vs. no involvement (5.0, range 2.1-18.1). SUVmax was found to be a predictor of cortical involvement (odds ratio = 1.17, P = 0.026). No significant correlation was found between SUVmax and pain or fracture (P = 0.43).

CONCLUSIONS

Improved medical treatment resulted improvement in 8% of patients with an actual or impending fracture. The orthopedic surgeons commonly use the Mirels classification for long bone fracture prediction. Adding PET/CT imaging to study in myeloma long bone lesions did not predict fracture risk directly but suggested it indirectly by cortical erosion.

Nonoperative Treatment of a Fractured Uncemented Extensively Coated Femoral Stem: A Case Report with 2-Year Follow-up

CASE

A 62-year-old man who underwent total hip arthroplasty (THA) 17 years earlier presented with a fractured uncemented extensively coated diaphyseal engaging femoral stem. Treatment options, including revision surgery, were discussed, and the patient elected for nonoperative treatment. At 2 years of follow-up, the patient is asymptomatic, radiographs are stable, and he lives an active lifestyle without restrictions.

CONCLUSION

Fractures of well-fixed femoral prostheses are rare complications of THA and almost universally require revision surgery. Nonoperative treatment without activity restrictions may be a viable treatment option in select patients to preserve function and maintain quality of life.

Current Methods for the Evaluation and Surgical Treatment of Periprosthetic Femur Fractures Complicating Hip Arthroplasty

Over the next decade, orthopedic surgeons will encounter an increasing number of periprosthetic fractures of the femur after hip arthroplasty. This rise is directly related to the increasing numbers of primary and revision hip arthroplasties being performed and the aging of the population. The Vancouver classification is the most widely used classification system for periprosthetic fractures of the femur occurring after hip arthroplasty. This classification considers the location of the fracture in relation to the femoral stem, the stability of the femoral stem, and the availability of femoral bone stock for revision. Most Vancouver AG and AL fractures can be treated nonsurgically, the exceptions being fractures associated with osteolysis and clamshell fractures of the lesser trochanter. B and C type fractures usually require operative intervention. Both Vancouver B1 and C types can be treated with fracture fixation alone, as the femoral implant is stable. Vancouver types B2 and B3 require femoral revision as the implant is loose. Distinguishing between types B1 and B2 can be difficult from radiographs alone and may require computed tomography and intraoperative testing.

Bilateral Femoral Fracture in an Adolescent Male Due to Severe Vitamin D Deficiency

PURPOSE/BACKGROUND

Mild to moderate vitamin D deficiency is common in pediatric patients in the U.S. Severe hypovitaminosis D has been linked to specific risk factors, such as female gender, obesity, winter season, darker skin, lack of exposure to the sun, and low vitamin D intake. It has been reported that adolescents usually experience less severe clinical symptoms than young children with vitamin D deficiency. We present a previously healthy 15-year-old Caucasian male with bilateral spontaneous femoral fracture due to severe hypovitaminosis rickets. He had unusual eating habits such as avoiding dairy, vegetables, and fruits. In addition to always preferring to eat alone due to anxiety. Patient is underweight with a BMI z score of -4.05 at time of presentation. Due to lack of interest in physical activities, the patient spent most of his time indoors.

DESIGN/METHODS

This is a case report of a patient who presented to the children's hospital for further workup for bilateral spontaneous femoral fractures.

FINDINGS/RESULTS

Laboratory work up revealed that his 25 hydoxy-vitamin D level was less than 4 ng/ml, calcium level was 5.7 mg/dl (8.4-10.5mg/dL), and phosphorus was 3.5 mg/dl (3.7-4.7 mg/dl). His intact parathyroid hormone was elevated at 555 pg/ml (14-95 pg/ml) and alkaline phosphatase was elevated at 777 U/L (91-339 U/L). A wrist x-ray showed widening of the distal radial and ulnar metaphyses with metaphyseal cupping. Further labs showed macrocytic anemia and severe vitamin B12 deficiency. Workup for malabsorption was negative. Patient underwent bilateral open hip reduction internal fixation. Hypovitaminosis D and hypocalcemia were treated with calcium carbonate and oral vitamin D3 supplements. His follow up laboratory evaluation showed normalization of his calcium, phosphorus, PTH, alkaline phosphatase, and vitamin D levels. Repeat wrist X-ray two months later revealed marked improvement in the appearance of the distal radial and ulnar growth plates and metaphyseal regions.

CONCLUSIONS

This patient's vitamin D deficiency/rickets was found to be secondary to malnutrition due to limited intake, along with limited sunlight exposure. We recommend that a detailed dietary history is obtained in every adolescent patient to evaluate for proper vitamin D intake, especially in patients who are significantly underweight. If vitamin D deficiency is expected, vitamin D level should be checked and appropriate treatment should be initiated once vitamin D insufficiency is confirmed.

The Genetics of Atypical Femur Fractures-a Systematic Review

PURPOSE OF REVIEW

Atypical femur fractures (AFFs) are rare subtrochanteric or diaphyseal fractures regarded as side effects of bisphosphonates (BPs), possibly with a genetic background. Here, we summarize the most recent knowledge about genetics of AFFs.

RECENT FINDINGS

AFF has been reported in 57 patients with seven different monogenic bone disorders including hypophosphatasia and osteogenesis imperfecta; 56.1% had never used BPs, while 17.5% were diagnosed with the disorder only after the AFF. Gene mutation finding in familial and sporadic cases identified possible AFF-related variants in the GGPS1 and ATRAID genes respectively. Functional follow-up studies of mutant proteins showed possible roles in AFF. A recent small genome-wide association study on 51 AFF cases did not identify significant hits associated with AFF. Recent findings have strengthened the hypothesis that AFFs have underlying genetic components but more studies are needed in AFF families and larger cohorts of sporadic cases to confirm previous results and/or find novel gene variants involved in the pathogenesis of AFFs.