Risk factors for overgrowth after flexible intramedullary nailing for fractures of the femoral shaft in children

Surgical treatment of osteogenesis imperfecta: a summary of the incidence of femoral implant-related complications in children with Sillence type I, III and IV

PURPOSE

This study explored the incidence of IRCs used in the procedures of the femur in children with osteogenesis imperfecta (OI) and investigated the independent risk factors of IRCs.

METHODS

Three hundred eight-eight cases of surgical data about children with OI were included, who were treated with plate, elastic nail, Kirschner wire and telescopic rod. The choice of different procedures depended on the age of children, the status of femur and the availability of devices. Patient demographics and major IRCs were recorded to compare the outcomes of the four procedures. Then, Cox proportional hazard regression was used to analyse the independent risk factors of IRC, and subgroup analysis was applied to further verify the above results.

RESULTS

The total incidence of IRC in the four groups was 90.1% (191/212) for plate, 96.8% (30/31) for Kirschner wire, 87.7% (57/65) for elastic nail and 30.0% (24/80) for telescopic rod. The incidence of IRC in the telescopic rod was lower than that in plate, elastic nail and Kirschner wire (P < 0.001). Cox proportional hazard regression analysis confirmed that procedure was the independent risk factor of IRC (HR, 0.191; 95% CI, 0.126-0.288; P < 0.001), fracture (HR, 0.193; 95% CI, 0.109-0.344; P < 0.001) and deformity (HR, 0.086; 95% CI, 0.027-0.272; P < 0.001). In addition, age of surgery was the independent risk factor of fracture (HR, 0.916; 95% CI, 0.882-0.952; P < 0.001) and deformity (HR, 1.052; 95% CI, 1.008-1.098; P = 0.019). Subgroup analysis confirmed that age of surgery, gender, classification, preoperative state and angle did not affect the effect of telescopic rod on reducing the risk of IRCs.

CONCLUSIONS

In our cohort, lower incidence of IRCs was observed in telescopic rod group compared with plate, Kirschner wire and elastic nail. Procedure and age of surgery were independent risk factors of fracture. Likewise, procedure and age of surgery were independent risk factors of deformity, and procedure was independent risk factors of IRC.

Risk factors for femoral overgrowth after femoral shortening osteotomy in children with developmental dysplasia of the hip

Objective

Developmental dysplasia of the hip (DDH) refers to a series of deformity of acetabulum and proximal femur and abnormal relationship between them, it represents the most common hip disease in children. Overgrowth and limb length discrepancy (LLD) was common complication in children undergoing femoral shortening osteotomy. Therefore, the purpose of this study was to explore the risk factors of overgrowth after femoral shortening osteotomy in children with DDH.

Methods

We included 52 children with unilateral DDH who underwent pelvic osteotomy combined with femoral shortening osteotomy between January 2016 and April 2018, including seven males (six left and one right hip) and 45 females (33 left and 12 right hips) with an average age of 5.00 ± 2.48 years, and an average follow-up time of 45.85 ± 6.22 months. The amount of overgrowth and limb length discrepancies (LLDs) were calculated. The risk factors of femoral overgrowth ≥1 cm and LLD ≥ 1 cm were analyzed.

Results

There were statistical differences in age (p < 0.001) and operation duration (p = 0.010) between the two groups with femoral overgrowth <1 cm and ≥1 cm. There was a statistical difference in operation duration (p < 0.001) between the two groups. Age (p < 0.001) was an independent influencing factor of femoral overgrowth in children with unilateral DDH after pelvic osteotomy and femoral shortening osteotomy, and a risk factor (p = 0.008) of LLD in these children.

Conclusion

The overgrowth and LLD of children with developmental dislocation of hip after pelvic osteotomy and femoral shortening osteotomy are significantly related to age. There was no significant difference between different pelvic osteotomies for femoral overgrowth in children. Therefore, surgeons should consider the possibility of LLD after femoral shortening osteotomy in children of a young age.

[Risk factors of adverse long-term consequences of tibial shaft fractures in children]

OBJECTIVE

To analyze leg length discrepancy and overgrowth after tibial shaft fractures in children.

MATERIAL AND METHODS

We analyzed medical records of 103 patients younger 14 years old with tibial shaft fractures between January 2003 and November 2018. Treatment included plastering and insertion of titanium elastic nail. To identify the risk factors of leg length discrepancy ≥1 cm and overgrowth ≥1 cm, we performed logistic regression analysis. Statistical analysis was carried out using the SPSS software for Windows.

RESULTS

Gender (p=0.014) and treatment methods (p=0.011) are the most significant predictors of leg length discrepancy and overgrowth. In boys, the risk of leg length discrepancy ≥1 cm was 7.4 times higher than in girls. The risk of leg length discrepancy ≥1 cm was 4.3 times higher after insertion of titanium elastic nail compared to plastering. The risk of overgrowth ≥1 cm was 5.4 times higher in boys than in girls. The risk of overgrowth ≥1 cm was 4.7 times higher after insertion of titanium elastic nail compared to plastering.

CONCLUSION

One should consider the risk of leg length discrepancy and overgrowth in children with tibial shaft fractures. This is especially true for boys undergoing insertion of titanium elastic nail.

Leg length discrepancy after skeletal maturity in patients treated with elastic intramedullary nails after femoral shaft fractures in childhood

PURPOSE

The purpose was to study radiographic and perceived leg length discrepancy after skeletal maturity in patients treated for femoral shaft fractures with elastic stable intramedullary nails in childhood.

METHODS

Thirty-five adults underwent standing radiographs and answered a questionnaire regarding perception of leg length discrepancy. Demographic data, fracture characteristics, angulation, stability of fixation, and callus formation, at time of fracture, were assessed.

RESULTS

Mean age at fracture was 10.2 (4.9-16.7) years, and mean follow-up time was 11.1 (3.8-16.8) years. In 8 of 35 participants, the fractured limb was 11-15 mm longer than the non-fractured, and in 16, 1-10 mm longer. In eight participants, the fractured limb was 1-10 mm shorter than the non-fractured, and in three participants, 12-23 mm shorter. The younger the child, the greater the lengthening (R_s = -0.49, p = 0.003). The greater the femoral angulation at time of fracture, the greater the shortening (R_s = 0.42, p = 0.013). There was no significant correlation between stability of fixation or callus formation 1 month postoperatively and radiographic leg length discrepancy after skeletal maturity. Fourteen (40%) had perception of leg length discrepancy at follow-up, of whom eight had a radiographic leg length discrepancy of 10-24 mm.

CONCLUSION

Treatment with elastic stable intramedullary nail of femoral shaft fracture in childhood may result in radiographic leg length discrepancy. Younger children were more prone to lengthening and should possibly be assessed before skeletal maturity. The degree of fracture stability or callus formation at the time of fracture did not significantly affect leg length discrepancy. Perception of leg length discrepancy was not necessarily associated with a radiographic leg length discrepancy (≥10 mm).

LEVEL OF EVIDENCE

level IV, case series.

Elastic Stable Intramedullary Nailing and Temporary External Fixation for the Treatment of Unstable Femoral Shaft Fractures in Children Aged 5-11 Years Old: A Retrospective Study of 28 Cases

PURPOSE

Unstable femoral shaft fractures (UFSFs) in children aged 5-11 years remain challenging due to their intrinsic instability. The aim of this study was to evaluate the clinical and radiographic outcomes of UFSF in children aged 5 to 11 years managed by the combined use of ESIN and temporary EF.

METHODS

Children with UFSF (long oblique and comminuted) treated by ESIN and temporary EF were retrospectively reviewed. Sex, age at injury, side involved, type of fracture, presence or absence of associated lesions or neurovascular complications, type of treatment, time from trauma to surgery, duration of surgery, radiation exposure and length of postoperative immobilization were collected from the medical charts. Radiological and functional outcomes were evaluated according to Beaty's and Flynn's criteria, respectively.

RESULTS

A total of 28 consecutive patients with closed or open (Gustilo type I or II) UFSF were reviewed (18 boys and 10 girls). The mean age at injury was 8.7 ± 1.6 years (range, 5-11); the average weight was 38.1 ± 7.6 kg (range, 26-55). The mean hospital stay was 3.7 ± 1.4 days (range, 2-7), and the mean time to EF and ESIN removal was 6.5 ± 1.1 weeks (range, 4-8) and 9.4 ± 1.6 months (range, 6-12), respectively. Twenty-seven out of 28 patients had excellent radiographic outcomes according to Beaty's criteria, and 24/28 had excellent functional outcomes according to Flynn's criteria. Overall, 4 complications (14.3%) were recorded. No statistically significant correlation was found between complication rates and sex, age, weight or fracture characteristics (P < 0.05).

CONCLUSIONS

The combined use of ESIN and temporary EF provides good clinical and radiological outcomes in children with UFSF aged between 5 and 11 years, with a reduced complication rate.

Leg-length discrepancy and associated risk factors after paediatric femur shaft fracture: a multicentre study

PURPOSE

This study was performed to investigate leg-length discrepancy (LLD) and associated risk factors after paediatric femur shaft fractures.

METHODS

A total of 72 consecutive patients under 13 years old (mean age 6.7 years; 48 boys, 24 girls) with unilateral femur shaft fracture, and a minimum follow-up of 18 months, were included. The amount of LLD was calculated by subtracting the length of the uninjured from that of the injured limb. Risk factors for an LLD ≥ 1 cm and ≥ 2 cm were analyzed using multivariable logistic regression analysis.

RESULTS

Hip spica casting, titanium elastic nailing and plating were performed on 22, 40 and ten patients, respectively. The mean LLD was 7.8 mm (sd 8.8) and 29 (40.3%) had a LLD of ≥ 1 cm, while nine (12.5%) had a LLD of ≥ 2 cm. There were significant differences in fracture stability (p = 0.005) and treatment methods (p = 0.011) between patients with LLD < 1 cm and ≥ 1 cm. There were significant differences in fracture site shortening (p < 0.001) and LLD (p < 0.001) between patients with length-stable and length-unstable fractures. Fracture stability was the only factor associated with LLD ≥ 1 cm (odds ratio of 4.0; p = 0.020) in the multivariable analysis.

CONCLUSION

This study demonstrated that fracture stability was significantly associated with LLD after paediatric femur shaft fractures. Therefore, the surgeon should consider the possibility of LLD after length-stable femur shaft fracture in children.

LEVEL OF EVIDENCE

Prognostic level III.

Remodelling in Children's Fractures and Limits of Acceptability

Remodeling follows inflammatory and reparative phases of bone healing and is very pronounced in children. Unlike adults, in growing children, remodeling can restore the alignment of initially malunited fractures to a certain extent, making anatomic reduction less essential. Remodeling is not universal and ubiquitous. Animal experiments and clinical studies have proven that in a malunited fracture, the angulation corrects maximally by physeal realignment (75%) and partly by appositional remodeling of the diaphysis also known as the cortical drift (25%). Remodeling potential reduces with the increasing age of the child; lower extremities have higher remodeling potential compared to the upper extremity. Remodeling is most pronounced at the growing end of the bone and in the axis of the adjacent joint motion. Correction of a very small amount of rotational malalignment is possible, but it is clinically not relevant. Overgrowth of the bone after a fracture occurs due to hyperaemia of fracture healing. Overgrowth is the most common after paediatric femur fractures, though it is reported after fractures of the tibia and humerus as well. The orthopaedic surgeon treating children's fractures should be familiar with regional variations of remodeling and limits of acceptance of angulation in different regions. Acceptability criteria for different bones are though well defined, but serve best as guidelines only. For the final decision-making patient's functional capacity, parents' willingness to wait until the completion of the remodeling process, and the experience of treating doctor should be considered concurrently. In case of the slightest doubt, a more aggressive approach should be taken to achieve a satisfactory result.

Functional and radiological outcome after forearm plating in children and adolescent fracture

The literature on forearm overgrowth after plating in traumatic conditions is relatively poor though this technique can be useful when intra-medullary nailing is not sufficient in pediatric cases. The goal of this study was to assess a potential overgrowth after plating and identify impact on function. We conducted a retrospective study of all pediatric patients who underwent open surgery of the radius and/or ulna diaphysis with internal fixation by plating, in our institution, between October 2013 and July 2019. At last follow-up, functional and radiological outcomes were compared between the operated and uninjured forearm. Range of motion (ROM) of the wrist and elbow, clinical scores, radial and ulnar length were measured. A positive bone length discrepancy of more than 2mm was considered as an overgrowth. Were also studied the radio-ulnar index, radial inclination and radiocarpal angle. Thirteen patients were included. The mean age was 12.1 years old (±3.0 years), they were plated on the radius (10 cases) or on the ulna (3 cases). Mean follow- up was 4.4 years (± 1.8). In two cases, the plated bone (radius) was significantly longer than the uninjured one. There was no significant difference regarding radio-ulnar index, radial inclination and radiocarpal angle. The only statistically significant difference between the operated and uninjured forearm was the pronation/supination range, which was greater in the uninjured forearm (mean 160 ±48° versus 175 ±49°, p=0.01). This study confirms the good functional and radiological outcomes after plating even in a skeletally immature forearm. Level of evidence : IV.

Leg length discrepancy, overgrowth, and associated risk factors after a pediatric tibial shaft fracture

Background

This study was performed to investigate leg length discrepancy (LLD), overgrowth, and associated risk factors after pediatric tibial shaft fractures.

Materials and methods

This study included 103 patients younger than 14 years of age (mean age 7.1 years; 75 boys, 28 girls) with unilateral tibial shaft fracture and a minimum follow-up of 24 months. LLD was calculated as the difference between the lengths of the injured and uninjured limbs. Overgrowth was calculated by adding the fracture site shortening from the LLD. Risk factors were assessed in patients with LLD < 1 cm and ≥ 1 cm and overgrowth < 1 cm and ≥ 1 cm.

Results

Casting and titanium elastic nailing (TEN) were performed on 64 and 39 patients, respectively. The mean LLD and overgrowth were 5.6 and 6.4 mm, respectively. There were significant differences in sex (p = 0.018), age (p = 0.041), fibular involvement (p = 0.005), injury mechanism (p = 0.006), and treatment methods (p < 0.001) between patients with LLDs < 1 cm and ≥ 1 cm. There were significant differences in sex (p = 0.029), fibular involvement (p = 0.002), injury mechanism (p = 0.008), and treatment methods (p < 0.001) between patients with overgrowth < 1 cm and ≥ 1 cm. Sex and treatment methods were risk factors associated with LLD ≥ 1 cm and overgrowth ≥ 1 cm following pediatric tibial shaft fracture. The boys had a 7.4-fold higher risk of LLD ≥ 1 cm and 5.4-fold higher risk of overgrowth ≥ 1 cm than the girls. Patients who underwent TEN had a 4.3-fold higher risk of LLD ≥ 1 cm and 4.8-fold higher risk of overgrowth ≥ 1 cm than those treated by casting.

Conclusions

Patients undergoing TEN showed greater LLD and overgrowth than those undergoing casting, with boys showing greater LLD and overgrowth than girls. Surgeons should consider the possibility of LLD and overgrowth after pediatric tibial shaft fractures, especially when performing TEN for boys.

Level of evidence

Level III

Overgrowth of the Femur After Internal Fixation in Children With Femoral Shaft Fracture-A Multicenter Study

OBJECTIVES

To evaluate overgrowth after internal fixation for pediatric femur fracture and to identify any factors related with overgrowth in terms of fracture type and fixation method.

DESIGN

Retrospective comparative study.

SETTING

Multicenter, children's hospital and general hospital.

PATIENTS/PARTICIPANTS

Eighty-seven children between 4 and 10 years of age were included. Length-stable fracture was noted in 49 children, and length-unstable fracture was found in 38 children.

INTERVENTION

Thirty-six children were treated by minimal invasive plate osteosynthesis (MIPO), and elastic stable intramedullary nail fixation (ESIN) was used in 51 children.

MAIN OUTCOME MEASUREMENTS

The degree of overgrowth after internal fixation compared to fracture type, fracture site, and surgical method. Multivariable logistic regression analysis was conducted to identify factors related with overgrowth.

RESULTS

The average overgrowth of the femur was 10.5 ± 7.3 mm. There was no patient who required correction for final leg length discrepancy (>2 cm). There was no significant difference in overgrowth between ESIN (9.9 ± 7.2 mm) and MIPO (11.2 ± 7.6 mm) (P = 0.417). Overgrowth was similar among length-unstable fractures (12.3 ± 7.4 mm) and length-stable fractures (9.2 ± 7.0 mm), although it was statistically greater in length-unstable fractures (P = 0.048). In the MIPO group, length-unstable fractures were associated with an increased log odds of 6.873 for overgrowth of the femur (P = 0.042).

CONCLUSIONS

Femur overgrowth after internal fixation seems to not be a clinically significant problem, regardless of whether that be for length-stable or length-unstable fractures and whether they were treated by MIPO or ESIN. Length-unstable fracture may be a risk factor for overgrowth in children. However, the difference is very small, and the postoperative overgrowth would likely not be a significant factor in deciding the surgical plan.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for authors for a complete description of levels of evidence.

Spontaneous Hemarthrosis of the Knee - Late Complication of Flexible Femur Nailing: A Case Report

We present a case report of acute spontaneous knee hemarthosis due to erosion of the nail through the knee joint capsule in a boy, seven months following retrograde flexible nailing for fractured femur. Careful positioning of the location of the insertion site of flexible nails and proper nail tip management are important to avoid this rare late complication.

[Femoral shaft fractures in children under 3 years old. Current treatment standard]

INTRODUCTION

Femoral shaft fractures in children are a common injury. Operative treatment is recommended for children above 3 years of age. The question of this investigation was the current clinical standard for the treatment of femoral shaft fractures in children under 3 years old.

MATERIAL AND METHODS

An e-mail questionnaire was sent to all clinics and hospital departments of the members of the German Society for Trauma Surgery and the German Society of Pediatric Surgery.

RESULTS

Out of 775 clinics and departments, 121 participated in the survey (16 %). From 2011 to 2012 overall 756 femoral shaft fractures of children 3 years and younger were treated of which 375 (50 %) were stabilized with elastic stable intramedullary nailing (ESIN), 183 (24 %) with an overhead extension, 178 (23 %) with a plaster cast and 9 (1 %) with external fixation. Finally, operative treatment was used in 51 % compared to 49 % with conservative treatment.

DISCUSSION

Obviously, operative treatment of femoral shaft fractures in children younger than 3 years is routinely used despite the fact that there is no evidential basis for this approach. There are good arguments for and against operative and conservative forms of treatment. Indications for operative treatment include multiple trauma, open fractures, body weight over 20 kg, child already free walking and lack of stable fixation with conservative treatment. To achieve more evidence for the existing recommendation of the American Academy of Orthopaedic Surgeons (AAOS) and the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF, Working Group of the Scientific Medical Specialist Societies), further investigations are needed.

Surgical treatment of femoral diaphyseal fractures in children using elastic stable intramedullary nailing by open reduction at Yopougon Teaching Hospital

INTRODUCTION

Elastic stable intramedullary nailing (ESIN) has transformed children's femoral shaft fracture treatment, but this technique requires an image intensifier. Without it, open reduction is used to check fracture reduction and pin passage. The aim of this study was to describe our techniques and to evaluate our results at the middle term.

HYPOTHESIS

The open reduction and ESIN technique provides satisfactory results with few major complications.

PATIENTS AND METHODS

This was a retrospective study that focused on femoral diaphyseal fractures treated in the pediatric surgery unit at Yopougon Teaching Hospital (Abidjan, Côte d'Ivoire) between January 2007 and December 2013. Twenty children older than 6 years of age who underwent open reduction and ESIN without image intensifier assistance were included. Functional outcomes were assessed using Flynn's criteria. Postoperative complications and sequelae were recorded.

RESULTS

At the 16-month follow-up, the results were excellent in 11 (55%) cases, good in eight (40%), and poor in one (5%) case. The mean duration of surgery was 71min (range, 57-103 min). The mean time for bone healing was 11.6 weeks (range, 7-15 weeks) and the average time to nail removal was 6 months. Complications included wood infection (n=3), skin irritation (n=3), knee stiffness (n=2), malunion (n=3), scar (n=5), and leg length discrepancy (n=3).

DISCUSSION

Open reduction and ESIN yielded satisfactory results with few major complications. This method could be an alternative in low-income countries where the image intensifier is often unavailable.

LEVEL OF EVIDENCE

Level IV retrospective study.

Risk factors for limb overgrowth after the application of titanium elastic nailing in the treatment of pediatric femoral fracture

PURPOSE

The objective of this study was to discuss the risk factors of postoperative limb overgrowth after the application of titanium elastic nailing (TEN) in the treatment of pediatric femoral fractures as well as analyze the causes and provide guidance for clinical treatment.

METHODS

The study included children with femoral fractures who were treated with TEN at our hospital from February 2005 to December 2009. Their age, gender, weight, cause of injury, having head trauma or not, fracture site, fracture type and nail-canal diameter (NCD) ratio were recorded. Student's t-test, chi-square test or Fisher's exact test was used for univariate analysis of the above factors, and then multivariate logistic regression analysis was used to analyze the possible risk factors in order to determine which ones are associated with limb overgrowth after the application of TEN to treat children with femoral fractures.

RESULTS

Univariate analysis showed that the age, gender, weight, cause of injury, having head trauma or not, and the fracture site did not have a statistically significant association with limb overgrowth (P = 0.741, 0.900, 0.253, 0.739, 0.967 and 0.105, respectively). The fracture type and NCD ratio were significantly associated with limb overgrowth (P = 0.003 and 0.000, respectively). Multivariate logistic regression analysis demonstrated that the fracture type (P = 0.021, OR = 2.757) and NCD ratio (P = 0.002, OR = 2.422) were independent risk factors for limb overgrowth.

CONCLUSIONS

The main factors affecting postoperative limb overgrowth are the fracture type and NCD ratio. In order to avoid limb overgrowth, unstable fractures should be fixed as firmly as possible, and the NCD ratio should be ≥0.8.

An observational cohort study of the adoption of elastic stable intramedullary nailing for the treatment of pediatric femur fractures in Kumasi, Ghana

BACKGROUND

In high- and middle-income countries, elastic stable intramedullary nailing (ESIN) is the commonest treatment of femur fractures in children 5-11 years of age. At Komfo Anokye Teaching hospital (KATH) in Kumasi, Ghana, prior to this study all pediatric femur fractures were treated with skin traction to union. This study was designed to report the early results and costs of the adoption of ESIN at KATH to provide data to other low- and middle-income sites considering adoption of this surgical technique.

METHODS

An observational cohort study that included 84 pediatric patients ages 3-14 years presenting with closed femur fractures and treated with either skin traction or ESIN. Multivariate logistic regression was used to compare the rate of treatment success between treatment groups.

RESULTS

Treatment success (coronal and sagittal angulation less than 10 ° and shortening less than 15 mm at osseous union) was achieved in 92 % of the ESIN group versus 67 % of the skin traction group (odds ratio for ESIN group 9.28 (1.6-54.7); p = 0.0138). Average length of stay was significantly lower in the ESIN group (p = 0.001), but charges to patients were higher in the ESIN group (p < 0.001) because of the high cost of implants.

CONCLUSIONS

The initial experience of operative treatment of femoral shaft fractures in children using ESIN was positive, with improved rates of treatment success and no surgical complications. Because of the high cost of implants, direct costs of treatment remained higher with ESIN despite reductions in length of hospital stay.

Intramedullary fixation using Kirschner wires in children with osteogenesis imperfecta

BACKGROUND

Surgical treatment for osteogenesis imperfecta (OI) remains controversial. The use of elongating rods has become a mainstay in this treatment, and there have been many reports of the results of this procedure. In contrast, using nonelongating rods is considered to be the classic method. This older method is still used by surgeons who are concerned about the possibility of trauma on the articular surface due to arthrotomy at the insertion of the elongating rod or who are working in developing countries with fewer resources. We are among those who prefer the use of nonelongating rods to elongating rods. This article presents the results of intramedullary fixation using nonelongating rods such as Kirschner wires (K-wires) in children with OI and the proper timing of wire exchange to prevent further fracture.

METHODS

We treated 29 femora in 17 patients with OI by means of stabilization using K-wires. For these patients we calculated revision-free survival and analyzed the details of any fractures that occurred after the primary surgery. We also investigated the relations between the wire length ratio, which was defined as the ratio of the intramedullary wire length divided by the femoral length, and the fracture type.

RESULTS

The revision-free survival for the 29 primary procedures was 63% at 3 years, and 36% at 5 years. All fractures that occurred at the wire tip required additional surgery, whereas only 51% of fractures at other sites required additional surgery. The wire length ratio of wire-tip fractures was significantly lower than that of fractures at other sites. There is a significant difference in the incidence of wire-tip fractures and other fractures between ratios of 65% and 75%.

CONCLUSIONS

Wire exchange surgeries should be performed before the wire length ratio drops to <70%. This information could be useful for preventing further fractures that require surgery when OI patients are treated by intramedullary fixation with nonelongating rods.

LEVEL OF EVIDENCE

Level IV.

Changing trends in the management of children's fractures

The management of children's fractures has evolved as a result of better health education, changes in lifestyle, improved implant technology and the changing expectations of society. This review focuses on the changes seen in paediatric fractures, including epidemiology, the increasing problems of obesity, the mechanisms of injury, non-accidental injuries and litigation. We also examine the changes in the management of fractures at three specific sites: the supracondylar humerus, femoral shaft and forearm. There has been an increasing trend towards surgical stabilisation of these fractures. The reasons for this are multifactorial, including societal expectations of a perfect result and reduced hospital stay. Reduced hospital stay is beneficial to the social, educational and psychological needs of the child and beneficial to society as a whole, due to reduced costs.

Environmental temperature impact on bone and cartilage growth

Environmental temperature can have a surprising impact on extremity growth in homeotherms, but the underlying mechanisms have remained elusive for over a century. Limbs of animals raised at warm ambient temperature are significantly and permanently longer than those of littermates housed at cooler temperature. These remarkably consistent lab results closely resemble the ecogeographical tenet described by Allen's "extremity size rule," that appendage length correlates with temperature and latitude. This phenotypic growth plasticity could have adaptive significance for thermal physiology. Shortened extremities help retain body heat in cold environments by decreasing surface area for potential heat loss. Homeotherms have evolved complex mechanisms to maintain tightly regulated internal temperatures in challenging environments, including "facultative extremity heterothermy" in which limb temperatures can parallel ambient. Environmental modulation of tissue temperature can have direct and immediate consequences on cell proliferation, metabolism, matrix production, and mineralization in cartilage. Temperature can also indirectly influence cartilage growth by modulating circulating levels and delivery routes of essential hormones and paracrine regulators. Using an integrated approach, this article synthesizes classic studies with new data that shed light on the basis and significance of this enigmatic growth phenomenon and its relevance for treating human bone elongation disorders. Discussion centers on the vasculature as a gateway to understanding the complex interconnection between direct (local) and indirect (systemic) mechanisms of temperature-enhanced bone lengthening. Recent advances in imaging modalities that enable the dynamic study of cartilage growth plates in vivo will be key to elucidating fundamental physiological mechanisms of long bone growth regulation.