Bone Material Strength Index as Measured by Impact Microindentation is Low in Patients with Primary Hyperparathyroidism

CONTEXT

In primary hyperparathyroidism (PHPT) bone mineral density (BMD) is typically decreased in cortical bone and relatively preserved in trabecular bone. An increased fracture rate is observed however not only at peripheral sites but also at the spine, and fractures occur at higher BMD values than expected. We hypothesized that components of bone quality other than BMD are affected in PHPT as well.

OBJECTIVE

To evaluate bone material properties using impact microindentation (IMI) in PHPT patients.

METHODS

In this cross-sectional study, the Bone Material Strength index (BMSi) was measured by IMI at the midshaft of the tibia in 37 patients with PHPT (28 women), 11 of whom had prevalent fragility fractures, and 37 euparathyroid controls (28 women) matched for age, gender, and fragility fracture status.

RESULTS

Mean age of PHPT patients and controls was 61.8 ± 13.3 and 61.0 ± 11.8 years, respectively, P = .77. Calcium and PTH levels were significantly higher in PHPT patients but BMD at the lumbar spine (0.92 ± 0.15 vs 0.89 ± 0.11, P = .37) and the femoral neck (0.70 ± 0.11 vs 0.67 ± 0.07, P = .15) were comparable between groups. BMSi however was significantly lower in PHPT patients than in controls (78.2 ± 5.7 vs 82.8 ± 4.5, P < .001). In addition, BMSi was significantly lower in 11 PHPT patients with fragility fractures than in the 26 PHPT patients without fragility fractures (74.7 ± 6.0 vs 79.6 ± 5.0, P = .015).

CONCLUSION

Our data indicate that bone material properties are altered in PHPT patients and most affected in those with prevalent fractures. IMI might be a valuable additional tool in the evaluation of bone fragility in patients with PHPT.

Outcomes of Short Versus Long Leg Casts for Childhood Accidental Spiral Tibial CAST Fractures

OBJECTIVE

The objective of the current study was to analyze the outcomes of short versus long leg casts in the treatment of childhood accidental spiral tibial (CAST) fractures.

METHODS

A retrospective review was performed of medical records at a single tertiary children's hospital from 2009 to 2014 of children with distal, spiral tibial fractures (CAST fractures). The following points were documented for each patient: sex, laterality of fracture, age at presentation, type of cast, length of time in cast, use of a controlled ankle motion boot after cast removal, suspicion for abuse, and complications including skin irritation, skin breakdown, infection, compartment syndrome, fracture displacement, and gait disturbances.

RESULTS

A total of 21 patients with an age range of 12 to 62 months were found to have CAST fractures as confirmed by x-ray. Fourteen were treated with short leg casts, whereas 7 were treated with long leg casts. Both groups healed with equal outcomes, and there was no documented suspicion for abuse in any case.

CONCLUSIONS

A short leg walking cast seems to be an effective and safe method of treatment for CAST fractures and could be considered as potentially preferable to long leg casts because of the added benefits of increased mobility and function. Follow-up to this preliminary study is warranted to better elucidate any differences in benefit between these treatment options, and clinical judgment should be used when considering immobilization options.

Anterior horizontal rafting plate to treat complex osteoporotic tibial plateau fractures: a technical note

Complex tibial plateau fractures in elderly patients exhibiting severe osteoporosis and articular surface collapse are challenging. Decision-making is difficult when the posterior column is involved. Open reduction and internal fixation of complex tibial plateau fractures in patients with severe osteoporosis are prone to failure. In this paper, we describe a new method for the maintenance of the articular surface of complex tibial plateau fractures in elderly patients. An anterior horizontal rafting plate (3.5-mm-thick reconstruction and locking plate [Zimmer Inc., Warsaw, IN, USA]) is placed via conventional posteromedial and anterolateral incisions. The plate is inserted between the anterior bony surface of the proximal tibia and the subpatellar fat pad; plate positioning is checked under direct vision. The patient is encouraged to begin functional recovery soon after operation. Progressive weight-bearing begins at 10 weeks postoperatively and is gradually increased during fracture healing. Clinical follow-up was performed at 4, 8, and 12 weeks, 6 and 12 months, and yearly thereafter. No articular collapse or fragment displacement was evident on three-dimensional computed tomography performed 6 months after surgery. The knee range of motion was 5-130º at the last follow-up (4 years after surgery). This technique may be a good option for treating complex tibial plateau fractures, especially in elderly patients with severe osteoporosis.

The degree of correction in open-wedge high tibial osteotomy compromises bone healing: A consecutive review of 101 cases

BACKGROUND

The bone healing in open-wedge high tibial osteotomy (OWHTO) proceeds gradually by a filling of the osteotomy gap. This can comprise several risk factors.

METHODS

A retrospective study analysed the clinical and radiological course of 101 consecutive OWHTOs in 96 patients. The following risk factors were considered: age, body mass index, tobacco consumption, amount of tobacco consumption, severity of comorbidities, infection of the surgical area, occurrence of a lateral hinge fracture and the degree of correction. The bone healing was evaluated by using the modified Radiographic Union Score for Tibial fractures (RUST).

RESULTS

A disturbance in bone healing was observed in 16 of the 101 osteotomies. Binary logistic regression analysis showed a correlation between the angle of the opening wedge and the development of a disturbance in bone healing (P = 0.002). The odds ratio indicated an increase in the risk of a disturbance in bone healing of 56% with each additional degree of correction. For the risk factor 'age' a statistical trend was recognizable (P = 0.077) with the risk of a disturbance in bone healing in higher age.

CONCLUSION

Lateral hinge fractures seem not to have a detrimental effect on the filling of the osteotomy gap. An increase in the opening wedge bears the risk of a disturbance in bone healing.

Prevalence and influencing factors of nonunion in patients with tibial fracture: systematic review and meta-analysis

OBJECTIVE

The aim of this study is to assess the prevalence of nonunion in patients with tibia fracture and the association between influencing factors and tibia fracture nonunion.

METHOD

A database searches of PubMed, the Cochrane Library, EMBASE, China National Knowledge Infrastructure (CNKI), Weipu database, and Wanfang database from inception until June 2019 was conducted. The pooled prevalence, odds ratio (OR), and 95% confidence intervals (CI) were calculated with Stata software.

RESULTS

In this study, 111 studies involving 41,429 subjects were included. In the study of the relationship between influencing factors and tibia fracture nonunion, 15 factors significantly influenced the fracture union, including > 60 years old, male, tobacco smoker, body mass index > 40, diabetes, nonsteroidal anti-inflammatory drugs (NSAIDs) user, opioids user, fracture of middle and distal tibia, high-energy fracture, open fracture, Gustilo-Anderson grade IIIB or IIIC, Müller AO Classification of Fractures C, open reduction, fixation model, and infection.

CONCLUSION

The prevalence of nonunion in patients with tibia fracture was 0.068 and 15 potential factors were associated with the prevalence. Closed reduction and minimally invasive percutaneous plate osteosynthesis (MIPPO) have the low risks of nonunion for the treatment of tibial fractures.

Treatment of Periprosthetic Nonunions of the Lower Extremity

Multiple studies have reported nonunion rates of 3% to 17% following peri-prosthetic fractures. Determining management strategies based on the available literature is difficult because existing studies are small and involve heterogeneous treatments and multiple surgeons. The purpose of this study was to describe a consecutive series of patients who presented to the authors' clinic with a periprosthetic nonunion of the lower extremity and to report the methods used to achieve limb salvage and the associated complications. Patients were included if they were indicated for surgery for a nonunion of a periprosthetic fracture of the lower extremity that had previously undergone either closed or open intervention. A total of 26 patients were included in this study. Average follow-up was 58 months. Average age was 69 years, and 77% of the patients were female. Twenty-three patients had periprosthetic nonunions of the femur, with 6 being associated with total hip arthroplasty, 15 with total knee arthroplasty, and 2 with both a total hip arthroplasty and a total knee arthroplasty. Three patients had a periprosthetic nonunion of the tibia associated with a total knee arthroplasty. Limb salvage was successful in 25 of 26 cases. This was achieved by either healing of the nonunion using exuberant fixation with prosthesis revision when necessary (n=20) or resection of the nonunion with placement of a tumor prosthesis (n=5). Four of the 26 patients (15%) incurred at least 1 complication during treatment. Exuberant fixation of the nonunion (with prosthesis revision when necessary) or nonunion resection with placement of a tumor prosthesis was successful in 96% of cases. [Orthopedics. 2020;43(4):209-214.].

Tibial Stress Fracture Following Ankle Arthrodesis

BACKGROUND

End-stage ankle arthritis is frequently treated with either tibiotalar or tibiotalocalcaneal (TTC) arthrodesis, but the inherent loss of accommodative motion increases mechanical load across the distal tibia. Rarely, patients can go on to develop a stress fracture of the distal tibia without any antecedent traumatic event. The purpose of this study was to determine the incidence of tibial stress fracture after ankle arthrodesis, highlight any related risk factors, and identify the effectiveness of treatment strategies and their healing potential.

METHODS

A retrospective chart review was performed at 2 large academic medical centers to identify patients who had undergone ankle arthrodesis and subsequently developed a stress fracture of the tibia. Any patient with a tibial stress fracture before ankle arthrodesis, or with a nontibial stress fracture, was excluded from the study.

RESULTS

A total of 15 out of 1046 ankle fusion patients (1.4%) developed a tibial stress fracture at a mean time of 42 ± 82 months (range, 3-300 months) following the index procedure. The index procedure for these 15 patients who went on to subsequently develop stress fractures included isolated ankle arthrodesis (n = 8), ankle arthrodesis after successful subtalar fusion (n = 2), primary TTC arthrodesis (n = 2), and ankle arthrodesis subsequent to successful subtalar fusion with resultant ankle nonunion requiring revision TTC nailing (n = 3). Four patients had undergone fibular osteotomy with subsequent onlay strut fusion, and 5 had undergone complete resection of the lateral malleolus. Stress fracture location was found to be at the level of the fibular osteotomy in 2 patients and at the proximal end of an existing or removed implant in 9. Fourteen of the 15 patients had a nondisplaced stress fracture and were initially treated with immobilization and activity modification. Of these, 3 failed to improve with nonoperative treatment and subsequently underwent operative fixation (intramedullary nail in 2; plate fixation in 1). Only 1 of the 15 patients presented with a displaced fracture and underwent immediate plate fixation. All patients reported pain improvement and were ultimately healed at final follow-up.

CONCLUSION

In this case series review, we found a 1.4% incidence of tibial stress fracture after ankle arthrodesis, and both hardware transition points and a fibular resection or osteotomy appear to be risk factors. Operative intervention was required in approximately 25% of this population, but the majority of tibial stress fractures following ankle fusion were successfully treated nonoperatively, and ultimately all healed.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Minimising tibial fracture after unicompartmental knee replacement: A probabilistic finite element study

BACKGROUND

Periprosthetic tibial fracture after unicompartmental knee replacement is a challenging post-operative complication. Patients have an increased risk of mortality after fracture, the majority undergo further surgery, and the revision operations are less successful. Inappropriate surgical technique increases the risk of fracture, but it is unclear which technical aspects of the surgery are most problematic and no research has been performed on how surgical factors interact.

METHODS

Firstly, this study quantified the typical variance in surgical cuts made during unicompartmental knee replacement (determined from bones prepared by surgeons during an instructional course). Secondly, these measured distributions were used to create a probabilistic finite element model of the tibia after replacement. A thousand finite element models were created using the Monte Carlo method, representing 1000 virtual operations, and the risk of tibial fracture was assessed.

FINDINGS

Multivariate linear regression of the results showed that excessive resection depth and making the vertical cut too deep posteriorly increased the risk of fracture. These two parameters also had high variability in the prepared synthetic bones. The regression equation calculated the risk of fracture from three cut parameters (resection depth, vertical and horizonal posterior cuts) and fit the model results with 90% correlation.

INTERPRETATION

This study introduces for the first time the application of a probabilistic approach to predict the aetiology of fracture after unicompartmental knee replacement, providing unique insight into the relative importance of surgical saw cut variations. Targeted changes to operative technique can now be considered to seek to reduce the risk of periprosthetic fracture.

Evaluation of Fracture and Osteotomy Union in the Setting of Osteogenesis Imperfecta: Reliability of the Modified Radiographic Union Score for Tibial Fractures (RUST)

BACKGROUND

Evaluation of the union of osteotomies and fractures in patients with osteogenesis imperfecta (OI) is a critical component of patient care. Studies of the OI patient population have so far used varied criteria to evaluate bony union. The radiographic union score for tibial fractures (RUST), which was subsequently revised to the modified RUST, is an objective standardized method of evaluating fracture healing. We sought to evaluate the reliability of the modified RUST in the setting of the tibias of patients with OI.

METHODS

Tibial radiographs of 30 patients with OI fractures, or osteotomies were scored by 3 observers on 2 separate occasions. Each of the 4 cortices was given a score (1=no callus, 2=callus present, 3=bridging callus, and 4=remodeled, fracture not visible) and the modified RUST is the sum of these scores (range, 4 to 16). The interobserver and intraobserver reliabilities were evaluated using intraclass coefficients (ICC) with 95% confidence intervals.

RESULTS

The ICC representing the interobserver reliability for the first iteration of scores was 0.926 (0.864 to 0.962) and for the second series was 0.915 (0.845 to 0.957). The ICCs representing the intraobserver reliability for each of the 3 reviewers for the measurements in series 1 and 2 were 0.860 (0.707 to 0.934), 0.994 (0.986 to 0.997), and 0.974 (0.946 to 0.988).

CONCLUSIONS

The modified RUST has excellent interobserver and intraobserver reliability in the setting of OI despite challenges related to the poor quality of the bone and its dysplastic nature. The application and routine use of the modified RUST in the OI population will help standardize our evaluation of osteotomy and fracture healing.

LEVEL OF EVIDENCE

Level III-retrospective study of nonconsecutive patients.

Case Report: Description of two fractures during the use of a powered exoskeleton

Introduction

Powered robotic exoskeletons are a promising solution to enable standing and walking in patients with spinal cord injury (SCI). Although training and walking with an exoskeleton in motor complete SCI patients is considered safe, the risks of unexpected (technical) adverse events and the risk of fractures are not fully understood. This article reports the occurrence of two different cases of bone fracture during exoskeleton usage. Furthermore, advice is given for extra safety training and instructions.

Case presentation

The first case concerns a 47-year-old woman with T12 AIS A SCI. Her exoskeleton shut down unexpectedly probably causing a misalignment of the joints of her lower extremities relative to the joints of the exoskeleton, which resulted in a fracture of her left tibia. The second case involves a 39-year-old man with L1 AIS B SCI. An unexpected fracture of the right distal tibia occurred without a specific prior (traumatic) incident.

Discussion

Exoskeleton training instructors, SCI patients and their buddies should be instructed how to handle emergency situations. Furthermore, they should be aware of the risk of stress fractures of the lower extremities. Proper alignment of the exoskeleton relative to the body is of utmost importance to reduce fracture risk. In the case of swelling and discoloring of the skin, radiographic examination should be performed in order to exclude any fracture.

Tibial plateau fracture related to unicompartmental knee arthroplasty: Two case reports and literature review

RATIONALE

Unicompartmental knee arthroplasty (UKA) is an effective method to treat single compartment disease of the knee joint. Report about the complications of UKA, especially tibial plateau fractures, is rare. Given its rarity, its pathogenesis is not well described, and a standard of treatment is still not established. Therefore, relevant studies and analysis of this complication have a significant effect on helping physicians avoid risks and guide clinical diagnosis and treatment.

PATIENT CONCERNS

The 1st case corresponds to a 70-year-old male patient who complained of knee pain, difficulty walking, nocturnal rest pain, and elevated skin temperature at 3 weeks after the left knee arthroplasty. The second case is a 72-year-old female patient who complained of left knee pain and swelling during movement at 2 weeks after the left knee arthroplasty.

DIAGNOSIS

The 1st case showed a fracture of the medial malleolus of the left knee and a secondary depression of the medial tibial plateau in X-rays and the second case showed a fracture of the medial malleolus of the left knee in computed tomography (CT) and X-rays.

INTERVENTIONS

The 1st case was treated with plate and screw fixation and the second case was treated conservatively and immobilized using brace and remained nonweight bearing for 6 weeks.

OUTCOMES

After 1 year, both patients have good joint activity, and there was no pain or loosening of the prosthesis and fragment displacement.

LESSONS

The incidence of tibial plateau fractures (TPF) related to UKA might be low, but fatal and difficult to treat. Its pathogenesis determines procedure-related factors; when fracture develops, treatment should be based on the degree of displacement, stability of implant fixation, etc.

Epidemiological evaluation of traumatic lower limb fractures in children: Variation with age, gender, time, and etiology

To investigate the age, gender, time, and etiology differences of traumatic lower limb fractures (TLLFs) in a population of children (≤18 years old), we retrospectively reviewed 936 children who had TLLFs and who came to our university-affiliated hospitals from 2001 to 2010. This study enrolled 657 males (70.2%) and 279 females (29.8%) aged (11.6 ± 4.9) years old. The most common etiologies and fracture sites were motor vehicle collisions (MVCs, 440, 47.0%) and tibias (376, 40.2%). A total of 126 (13.5%) patients suffered neurological deficits (NDs), 127 (13.6%) patients sustained associated injuries (ASOIs), and 78 (8.3%) patients sustained complications. During all periods the occurrence increased with increasing age group and a male preponderance was observed in all age groups. With increasing age, the proportion of injuries due to different etiologies increased and the proportion of femur fracture decreased from 65.2% to 34.5%. With increasing year of admission, the proportion of injuries due to MVCs decreased. The most common fracture sites were tibias in MVCs, femurs in low fall, high fall, and struck by object, feet in sprain. Male patients presented with significantly higher proportions of injuries due to struck by object and sprain, significantly lower proportions of pelvis fracture than the female patients. MVCs and tibias were the most common etiologies and fracture sites. Prevention and treatment should be taken according to the pattern of TLLFs which have specific annual, gender, and age characteristics.

Tibial Shaft Fractures in Workers Compensation and No-Fault Insurance Is There a Difference in Resource Utilization?

BACKGROUND

Workers Compensation claims have been previously associated with inferior clinical outcomes. However, variation in inpatient stays for orthopedic trauma injuries according to insurance type has not been previously examined.

METHODS

We investigated the differences according to insurance for tibial shaft fractures in regard to length of stay and disposition. Using the New York SPARCS database, we identified 1,856 adult non-elderly patients with an isolated tibial shaft fracture who underwent surgery. Patients were stratified by insurance type, including private, Medicaid, Workers Compensation, and no-fault, which covers medical expenses related to automobile or pedestrian accidents.

RESULTS

Compared to private insurance (mean: 2.7 days), length of stay was longer for no-fault (mean: 3.9 days; adjusted difference +33%, p < 0.001) and Medicaid (mean: 3.5 days; adjusted difference +22%, p < 0.001), but not significantly different for Workers Compensation (mean: 3.5 days; adjusted difference +4%, p = 0.474). Compared to private insurance (rate: 3.5%), disposition to a facility was significantly higher for no-fault (rate: 10.1%; adjusted odds ratio [OR] = 3.3, p < 0.001) and Medicaid (rate: 7.6%; OR = 2.2, p = 0.003), but was not significantly different for Workers Compensation (rate: 6.3%; OR = 1.8, p = 0.129).

CONCLUSIONS

Patients with no-fault insurance, but not Workers Compensation, are subject to longer hospital stays and are more likely to be discharged to a facility following operative fixation of an isolated tibial shaft fracture. These findings suggest that financial, social, and legal factors influence medical care for patients involved in automobile accidents with no-fault insurance.

Management of pediatric tibial tubercle fractures: Is surgical treatment really necessary?

Fractures of the anterior tibial tubercle are infrequent lesions. They often occur in male adolescent athletes, usually in relation with sports involving powerful jumps. We present a retrospective study of 10 patients, with an average age of 15.1 years, all of them males, and a total of 11 acute avulsions of the anterior tibial tubercle. We analyzed the etiology of the lesion, the type of treatment used as well as non-weight bearing period, protected immobilization period, and time until sports reincorporation. We obtained 11 acute avulsions: one case of type I; three cases of type II; four cases of type III; and three cases of type IV. Five cases were treated conservatively, including the three cases of type IV, and surgery was only performed in six cases since an anatomical reduction was not obtained with closed reduction. The results were satisfactory in all cases, with 100% percentage of sport reincorporation in less de 25 weeks. We registered only one complication, intolerance of material, which did not require additional surgeries. These fractures, although rare, have an excellent prognosis. Even if they are often treated surgically, we have obtained good results with the conservative treatment in patterns previously reported as surgical.

Analysing outcomes through orthopaedic trauma registry - A prospective cohort study

OBJECTIVE

To develop a registry for recording injury-specific data to identify gaps and improve care.

Methods

The prospective cohort study was conducted at Aga Khan University Hospital, Karachi, from June 2015 to July 2018 though enrollment of patients with limb trauma is continuing to date. Data on injuries and management related to Tibia shaft fractures was collected from medical records, and outcomes were assessed on follow-up visits. Internationally validated injury-specific scores were utilised for assessing functional, clinical and radiological outcomes. SPSS version 19 was used for data analysis.

Results

There were 763 patients with 825 limb injuries. Of the injuries, 310(37.6%) related to upper limbs and 515(62.4%) to the lower limbs. Management was surgical for 741(89.9%) and conservative for 84(10.1%) injuries. Overall, 12(1.57%) patients died, and in 7(0.91%) cases mortality was unrelated to trauma and its management. There were 105 patients with tibia shaft fractures. Of them, 88(83.8%) were males and 17(16.2%) were females. At one-year follow-up excellent-to-good results were 12(92%) for intramedullary nailing followed by 7(78%) for open reduction and internal fixation.

Conclusion

Registry data can be used to develop preventive strategies and to improve management protocols.

Severe hypophosphatemia induced by denosumab in a patient with osteomalacia and tenofovir disoproxil fumarate-related acquired Fanconi syndrome

Denosumab, a novel agent that inhibits osteoclasts, reduces the risk of fracture in patients with osteoporosis. However, worsening of hypophosphatemia and other symptoms may be induced by denosumab in patients with pre-existing hypophosphatemic osteomalacia. A 58-year-old man with hepatitis B presented with diffuse bone pain and muscle weakness. Denosumab was prescribed by the orthopedist according to documented low bone mass and spine compression fracture. After administering denosumab, the patient's bone pain worsened, and he later developed a right tibia stress fracture. His condition was diagnosed as adult-onset hypophosphatemic osteomalacia complicated by multiple bone fractures, which resulted from Fanconi syndrome with proximal tubulopathy due to tenofovir disoproxil fumarate (TDF) treatment for his hepatitis B. Denosumab use leads to aggressive hypophosphatemic osteomalacia and the complication of stress fractures, because of its effects on bone resorption. Physicians should be aware that in patients with chronic hepatitis B monoinfection who are administered TDF therapy, bone pain or fracture is possible but preventable by timely monitoring of serum phosphate levels. Denosumab should not be used in patients with untreated osteomalacia or vitamin D deficiency, as it may lead not only to hypocalcemia but also to hypophosphatemia in these patients.

Hyperbaric oxygen therapy for severe blast injury of lower extremity after terrorist attack: case report

More blast injuries are encountered in the civilian setting in recent years as terrorist attacks have increased globally. A 17-year-old male patient with severe blast injury of the right lower extremity was admitted to our department on the fifth day after a terrorist bombing attack. Initially he had been admitted to an emergency department with segmental tibia fracture and arterial injury (Gustilo IIIC). An amputation had been foreseen due to ischemia that persisted even after orthopedic fixation and revascularization interventions, followed by fasciotomy incisions. After consultation with our department hyperbaric oxygen (HBO2) therapy was administered twice daily for the first week. Ischemia improved prominently after 10 HBO2 sessions. HBO2 therapy was continued together with antibiotherapy and wound care. The patient underwent a total of 40 HBO2 sessions and two reconstructive operations and healed without amputation. Vascular injuries with concomitant orthopedic trauma cause most of the delayed amputations in bombing attacks since ischemia can persist at the microvascular level even though adequate treatments are applied. HBO2 corrects hypoxia at tissue level and so provides oxygen for the critically ischemic cells in the injured area. HBO2 also enhances host defense and decreases the ischemia reperfusion injury. In this case, HBO2 was effective in survival and functional recovery (salvage) of the extremity together with regular wound care, antibiotherapy and surgical repair.

Quantitative Ultrasound and Tibial Dysplasia in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder associated with unilateral anterolateral bowing with subsequent fracture and nonunion. In infancy, physiologic bowing of the lower leg can be confused with pathologic tibial dysplasia in NF1. Little is known about the bone physiology of the tibiae prior to fracture or predictors of fracture. The aim of this study was to characterize bone quality of bowed tibiae prior to fracture in NF1 using quantitative ultrasound (QUS). Bone quality was assessed on both tibiae (the non-bowed and bowed tibiae) using QUS to measure speed of sound (SOS) at the mid-shaft in 23 individuals with NF1. SOS (m/s) was determined and Z-scores generated using cross-sectional reference data of the same sex and age. The mean difference in SOS Z-scores when comparing the bowed tibia vs the individual's contralateral unaffected tibia was statistically significant with lower mean Z-scores in the bowed tibia (p = 0.001). Radiographs of all individuals with a clinical diagnosis of anterolateral bowing were reviewed, and in 2 individuals the radiographs showed minimal bowing with absence of characteristic cortical thickening and medullary canal narrowing in NF1-related tibial dysplasia, suggesting physiologic bowing. In both individuals, the Z-scores of the bowed leg were not lower than the unaffected leg supporting the suggestion of physiologic bowing rather than pathologic tibial dysplasia. These data show that dysplastic tibiae in NF1 prior to fracture and nonunion have abnormal bone quality with significant decreases in SOS even though radiographically the tibiae show a thickened cortex. These data also suggest that QUS can help distinguish dysplastic bowing vs physiologic bowing in infancy in NF1. QUS is an effective quantitative outcome measure for trials aimed at improving tibial bowing to prevent fracture, and it is a potential aid in diagnosis and clinical management in NF1.

Incidence of and Risk Factors for Knee Collateral Ligament Injuries With Proximal Tibia Fractures: A Study of 32,441 Patients

Proximal tibia fractures are associated with concurrent collateral ligament injuries. Failure to recognize these injuries may lead to chronic knee instability. The purpose of this study was to identify risk factors for concurrent collateral ligament injuries with proximal tibia fractures and their association with inpatient outcomes. A total of 32,441 patients with proximal tibia fractures were identified in the 2011-2012 National Trauma Data Bank. A total of 1445 (4.5%) had collateral ligament injuries, 794 (2.4%) had injuries to both collateral ligaments, 456 (1.4%) had a medial collateral ligament injury only, and 195 (0.6%) had a lateral collateral ligament injury only. On multivariate analysis, risk factors found to be associated with collateral ligament injuries included distal femur fracture (odds ratio, 2.1), pedestrian struck by motor vehicle (odds ratio, 2.0), obesity (odds ratio, 1.6), young age (odds ratio, 1.9 for 18 to 29 years vs 40 to 49 years), motorcycle accident (odds ratio, 1.5), and Injury Severity Score of 20 or higher (odds ratio, 1.4). In addition, patients with simultaneous injuries to both collateral ligaments had higher odds of inpatient adverse events (odds ratio, 1.51) and longer hospital stay (mean, 2.27 days longer). The risk factors reported by this study can be used to identify patients with proximal tibia fractures who may warrant more careful and thorough evaluation and imaging of their knee collateral ligaments. [Orthopedics. 2018; 41(2):e268-e276.].

Open-wedge high tibial osteotomy: incidence of lateral cortex fractures and influence of fixation device on osteotomy healing

PURPOSE

Open-wedge high tibial osteotomy (HTO) is an established treatment for young and middle-aged patients with medial compartment knee osteoarthritis and varus malalignment. Although not intended, a lateral cortex fracture might occur during this procedure. Different fixation devices are available to repair such fractures. This study was performed to evaluate osteotomy healing after fixation with two different locking plates.

METHODS

Sixty-nine medial open-wedge HTO without bone grafting were followed until osteotomy healing.

RESULTS

In patients with an intact lateral hinge, no problems were noted with either locking plate. A fracture of the lateral cortex occurred in 21 patients (30.4 %). In ten patients, the fracture was not recognized during surgery but was visible on the radiographs at the 6-week follow-up. Lateral cortex fracture resulted in non-union with the need for surgical treatment in three out of eight (37.5 %) patients using the newly introduced locking plate (Position HTO Maxi Plate), while this did not occur with a well-established locking plate (TomoFix) (0 out of 13, p = 0.023).

CONCLUSION

With regard to other adverse events, no differences between both implants were observed. In cases of lateral cortex fracture, fixation with a smaller locking plate resulted in a relevant number of non-unions. Therefore, it is recommended that bone grafting, another fixation system, or an additional lateral fixation should be used in cases with lateral cortex fracture.

LEVEL OF EVIDENCE

III.