Reverse Dynamization Accelerates Regenerate Bone Formation and Remodeling in a Goat Distraction Osteogenesis Model

UPDATE

This article was updated on December 20, 2023, because of previous errors, which were discovered after the preliminary version of the article was posted online. Figure 4 has been replaced with a figure that presents different p values. Also, on page 1943, the text that had read: "Quantitative microCT confirmed that the total volume of the regenerate in the RD group was much smaller compared with the SF (p = 0.06) and DF (p = 0.007) groups, although it was significantly smaller only compared with the DF group (Fig. 4-A). The total volume of the intact bone (contralateral tibia) was significantly smaller in the RD group compared with the other groups, but the RD group had values closest to those for the intact tibia. Similarly, the RD group had less bone volume compared with the SF and DF groups, and this value was significantly different from the DF group (p = 0.034; Fig. 4-B). Of the 3 groups, the RD group had vBMD that was the closest to that of intact bone. It also had significantly higher vBMD compared with the SF and DF groups (p < 0.0001 for both; Fig. 4-C).The results of torsional testing (Fig. 4-D) confirmed that the regenerate bone formed under conditions of RD was significantly stronger than that formed under SF or DF (p < 0.001 versus SF group, and p = 0.0493 versus DF group)."now reads: "Quantitative microCT confirmed that the total volume of the regenerate in the RD group was significantly smaller compared with the SF and DF groups (p < 0.01 for both groups; Fig. 4-A). The total volume of the intact bone (contralateral tibia) was significantly smaller compared with the SF and DF groups (p < 0.0001 for both). The RD group had values closest to those for the intact tibia, and this difference was not significant (Fig. 4-A). Similarly, the RD group had less bone volume compared with the SF and DF groups, and this value was significantly different from the DF group (p < 0.01; Fig. 4-B). Of the 3 groups, the RD group had vBMD that was the closest to that of intact bone, but the intact bone was significantly different compared with all of the other groups (p < 0.0001 for all groups). The RD group had significantly higher vBMD compared with the SF and DF groups (p = 0.042 and p = 0.046, respectively; Fig. 4-C).The results of torsional testing (Fig. 4-D) confirmed that the regenerate bone formed under conditions of RD was significantly stronger than that formed under SF or DF (p < 0.0001 versus SF group, and p = 0.0493 versus DF group). The intact group was significantly different compared with the SF group (p < 0.0001)."

Risk assessment of postoperative pneumonia in children with neurologic disorders and obesity

INTRODUCTION

Postoperative pneumonia increases the risk of postsurgical mortality, making it a serious healthcare-associated complication. Children with preoperative neuromuscular impairments have a higher risk of postoperative pneumonia. Obesity is also a risk factor for postoperative pulmonary complications, including pneumonia. Moreover, obesity is increasingly prevalent among children living with a neurological diagnosis. Whether obesity increases the risk of postoperative pneumonia among children with neurologic diseases remains largely unknown. Therefore, we assessed the risk of postoperative pneumonia among children with neurologic diagnoses based on their obesity status.

METHODS

We analyzed a retrospective cohort of children ≤18 years from the National Surgical Quality Improvement Program (2012-2019) database who underwent inpatient orthopedic surgery. We used Cox proportional regression model to estimate the hazard ratio for the association between neurologic disorders and postoperative pneumonia. In addition, we included an interaction term between body mass index and neurologic disorders to evaluate the moderating effect of obesity status and then performed stratified analyses to compare the magnitude of hazard ratios across body mass index subgroups.

RESULTS

A total of 60 745 children underwent inpatient orthopedic surgery during the study period, of whom 43.6% were healthy weight and 30.8% overweight/obese. The median age was 13 years (Interquartile range: 8-15). The incidence of postoperative pneumonia was higher among healthy weight patients with neurologic disorders than healthy weight patients without any neurologic disorders [Hazard ratio: 3.55 vs. 0.34]. Furthermore, the association between neurologic disorders and postoperative pneumonia was strongest among overweight patients than healthy weight or obese patients [Hazard ratio:11.88 vs. 9.45 vs. 4.40]. This observation was consistent across the various neurologic disorders analyzed.

CONCLUSION

Childhood obesity buffered the association between neurologic disorders and postoperative pneumonia, consistent with an 'obesity paradox'. Further research exploring the underlying mechanisms for the obesity paradox in children with neurologic disorders is warranted.

What matters to children with lower limb deformities: an international qualitative study guiding the development of a new patient-reported outcome measure

BACKGROUND

Lower limb deformities include conditions such as leg length discrepancy, lower limb deficiency and associated angular and rotational deformities of the hips, knees, ankles and feet. Children with lower limb deformities often have physical limitations due to gait irregularities and pain. The differences in the appearance and function of their lower limbs can discourage participation in social, recreational and leisure activities, which may result in behavioural, emotional, psychological and social adjustment problems. The health-related quality of life (HRQL) of these children is often impacted due to the factors discussed above, as well as by the complex surgical procedures. Surgical treatment options for limb deformities in children vary from limb lengthening and reconstruction to amputation. The lack of evidence demonstrating superiority of either treatment options and their effect on HRQL limits the ability of healthcare providers to counsel families on the best evidence-based treatment option for them. This manuscript describes the international qualitative study which guided the development of a new patient-reported outcome measure (PROM). Individual semi-structured face-to-face interviews with children with lower limb deformities and their parents were conducted at five sites: Canada (2 sites), Ethiopia, India and the USA.

RESULTS

Seventy-nine interviews were conducted at five international sites. Five main themes emerged from the qualitative interviews and formed the basis of the conceptual framework. These themes were: 1) appearance, 2) physical health, 3) psychological health 4) school and 5) social health.

CONCLUSIONS

Lower limb deformities have a substantial impact on the HRQL of children. The concepts of interest identified in our study were similar across children from all countries. The conceptual framework guided the development of outcome scales specific to these patients. The information about the impact of various treatment options on the HRQL of children with lower limb deformities, collected using this new PROM, could be used to inform parents and children about outcomes (physical, social, psychological) associated with specific treatment options. This information could supplement other objective outcome information (e.g., complication rates, how the leg will look, etc.) to help families to come to a more informed decision on a child's course of treatment.

Reverse Dynamization Accelerates Bone-Healing in a Large-Animal Osteotomy Model

BACKGROUND

Reverse dynamization is a mechanical manipulation regimen designed to accelerate bone-healing and remodeling. It is based on the hypothesis that a fracture that is initially stabilized less rigidly allows micromotion to encourage initial cartilaginous callus formation. Once substantial callus has formed, the stabilization should then be converted to a rigid configuration to prevent the disruption of neovascularization. The aim of the present study was to investigate whether bone-healing can be accelerated using a regimen of reverse dynamization in a large-animal osteotomy model.

METHODS

Transverse 2-mm tibial osteotomies were created in 18 goats, stabilized using circular external fixation, and divided into groups of 6 goats each: static fixation (rigid fixation), dynamic fixation (continuous micromotion using dynamizers), and reverse dynamization (initial micromotion using dynamizers followed by rigid fixation at 3 weeks postoperatively). Healing was assessed with the use of radiographs, micro-computed tomography, and mechanical testing.

RESULTS

Radiographic evaluation showed earlier and more robust callus formation in the dynamic fixation and reverse dynamization groups compared with the static fixation group. After 8 weeks of treatment, the reverse dynamization group had reduced callus size, less bone volume, higher bone mineral density, and no evidence of radiolucent lines compared with the static fixation and dynamic fixation groups. This appearance is characteristic of advanced remodeling, returning closest to the values of intact bone. Moreover, the tibiae in the reverse dynamization group were significantly stronger in torsion compared with those in the static fixation and dynamic fixation groups.

CONCLUSIONS

These findings confirmed that tibial osteotomies under reverse dynamization healed faster, healed objectively better, and were considerably stronger, all suggesting an accelerated healing and remodeling process.

CLINICAL RELEVANCE

This study demonstrates that the concept of reverse dynamization challenges the current understanding regarding the optimal fixation stability necessary to maximize the regenerative capacity of bone-healing. When reverse dynamization is employed in the clinical setting, it may be able to improve the treatment of fractures by reducing the time to union and potentially lowering the risk of delayed union and nonunion.

Regional Anesthesia for Pain Management After Orthopedic Procedures for Treatment of Lower Extremity Length Discrepancy

Introduction

The use of regional anesthesia techniques continues to expand in a wide variety of surgical procedures as the benefits and safety are increasingly appreciated. Limb-lengthening procedures are often associated with significant postoperative pain and high opioid requirements which may impact patient's recovery and increase risk of chronic pain and long-term opioid use.

Methods

The current study retrospectively reviews our experience utilizing a novel peripheral nerve catheter (PNC) protocol for postoperative pain management in patients undergoing elective limb-lengthening procedures. We measure total opioid consumption following 48 hrs in the postoperative period between groups.

Results

A total of 70 patients were included from which 41 received general plus regional anesthesia (RA) and 29 were managed with general anesthesia alone (NORA). Postoperative pain needs were calculated as morphine equivalents (ME). There were no differences in the demographic characteristics between the groups. Over the first 48 postoperative hours, opioid use was 0.5 mg/kg ME (IQR 0.3, 0.9) in the RA group versus 1.7 mg/kg ME (IQR 1.1, 3.1) in the NORA group (p<0.001). Subgroup analysis between femoral lengthening and tibial-fibular lengthening procedures demonstrated the same opioid-sparing effect favoring the RA group compared to the NORA group. Hospital length of stay was significantly shorter in the femoral lengthening RA group compared to NORA group (32 hrs [IQR 29, 35] versus 53 hrs [IQR 33, 55], respectively). There was no significant difference in length of stay between the RA group and NORA group after tibial-fibular lengthening procedures.

Discussion

Regional anesthesia via continuous catheter infusions has a clinically significant opioid-sparing effect for postoperative pain management after limb-lengthening procedures and may facilitate earlier hospital discharge.

Accuracy and Safety of Distal Femoral Valgus Correction: A Comparison of Three Techniques

Introduction

There are several methods for correcting distal femoral valgus deformity in skeletally mature patients including fixator-assisted plating (FAP), fixator-assisted nailing (FAN) and nailing using the reverse planning method. The fixator-assisted techniques have been previously compared in the literature and found to be similarly accurate. This study is the first to compare all three procedures in a single series.

Materials and methods

A retrospective review of patients who had undergone distal femoral valgus correction at a single institution between March 2017 and February 2020 was undertaken. Three different patient groups were identified based on the surgical technique used: the FAP, the FAN and the reverse planning method. The mechanical lateral distal fimoral angle (mLDFA) was recorded and compared preoperatively and postoperatively. The body mass index (BMI), duration of surgery, postoperative range of motion (ROM) and complication profile for each patient were also recorded and compared.

Results

A total of 27 limbs in 24 patients were included in this study. There were 8 male and 16 female patients. There were 10 limbs from 9 patients in the reverse planning group, 11 limbs from 11 patients in the FAN group and 6 limbs from 4 patients in the FAP group. There was a statistically significant difference in the mean preoperative and postoperative mLDFA for each of the individual groups (p < 0.0001 for each group). All patients had restoration of the mLDFA to within normal limits except one patient in the reverse planning group. This was purposefully performed to compensate for an ipsilateral proximal tibial deformity. There was no statistically significant difference in the mean preoperative and postoperative mLDFA across the groups (p = 0.2897 and 0.3440, respectively). The operative time of the reverse planning method and the FAP were significantly shorter than FAN (p = 0.0016 and p = 0.0035, respectively). The mean final knee ROM amongst the groups was similar (p = 0.8190). We recorded no infections or union complications in any group. There was one case of hardware irritation causing lateral knee pain that did not require treatment in the reverse planning group and one fracture through a temporary half-pin site in the FAN group. All six plates in the FAP group had to be removed following union on account of localised discomfort from the hardware.

Conclusion

The reverse planning method, the FAN and the FAP are comparable in terms of accuracy in achieving correction of distal femur valgus deformity in skeletally mature patients. The reverse planning method had the best combination of outcomes in this study since it was just as accurate as the FAN and the FAP techniques and did not require any additional surgeries. While both the reverse planning and the FAP were faster than the FAN technique, the reverse planning method allows the ability to perform both deformity correction and lengthening. Ultimately, the decision of which technique to use depends on a combination of the patient's preference and the surgeon's level of comfort with the technique.

How to cite this article

Iobst C, Waseemuddin M, Bafor A. Accuracy and Safety of Distal Femoral Valgus Correction: A Comparison of Three Techniques. Strategies Trauma Limb Reconstr 2020;15(1):41-46.

An Alternative Tibial Osteotomy Technique

Introduction

The anterior approach to a tibial osteotomy commonly employs a small incision and multiple drill holes followed by completion with an osteotome. Potential complications are damage to the anterior tibial periosteum and posterior neurovascular structures.

Materials and Methods

We describe an alternative method using two small incisions, which avoids elevation of the anterior tibial periosteum and directs the osteotome away from posterior neurovascular structures.

Results

This technique has been successfully performed on 15 consecutive tibias, with no neurovascular complications or skin healing issues.

Conclusion

This tibial osteotomy technique can be performed quickly and safely using a minimally invasive approach as an alternative to the traditional anterior approach.

How to cite this article

Iobst C. An Alternative Tibial Osteotomy Technique. Strategies Trauma Limb Reconstr 2020;15(1):47–49.

Long-term follow-up with mention of complications in pediatric microvascular mandibular reconstruction

The fibular free flap has become the gold standard for mandibular reconstruction. Despite its vast array of benefits, this procedure has the potential for several complications. In the pediatric setting, the immature skeleton sets the stage for an increased risk of future skeletal abnormalities, both in the jaw, and in the donor site. Herein we describe the case of a toddler who underwent mandibular reconstruction using a fibula free flap and, years later, subsequently developed ankle instability as a result of residual fibula migration. This indicates the need for careful consideration of long-term issues in the growing pediatric skeleton prior to surgery.

The half-pin and the pin tract: a survey of the Limb Lengthening and Reconstruction Society

Although the key principles of external fixation have changed little over the years, there remains a significant amount of variation in fixation methods and postoperative care. In particular, use and management of half-pins intended for prolonged reconstruction are the subject of strong opinions and intense debate. We conducted a study of common trends in use and management of half-pins and in treatment of pin-tract infections in circular fixation by polling subject matter experts who are members of the Limb Lengthening and Reconstruction Society. Although the distribution of stainless steel half-pins (52%) and titanium half-pins (48%) was similar, most respondents preferred hydroxyapatite coating (81%). Respondents commonly encouraged use of a shower (60%) and a washing solution (67%) for pin-site care. For pin-tract infections, oral antibiotics were prescribed more often (83%) than parenteral antibiotics (17%) and were given for 8 days on average. Results from this study helped identify trends in application techniques and in routine management of circular fixators. In addition, they helped identify several areas of clinical equipoise that should be studied, including metallurgy, pin-site care solutions, and antibiotics.

Pediatric and adolescent applications of the Taylor Spatial Frame

Limb deformity can occur in the pediatric and adolescent populations from multiple etiologies: congenital, traumatic, posttraumatic sequelae, oncologic, and infection. Correcting these deformities is important for many reasons. Ilizarov popularized external fixation to accomplish this task. Taylor expanded on this by designing an external fixator in 1994 with 6 telescoping struts that can be sequentially manipulated to achieve multiaxial correction of deformity without the need for hinges or operative frame alterations. This frame can be used to correct deformities in children and has shown good anatomic correction with minimal morbidity. The nature of the construct and length of treatment affects psychosocial factors that the surgeon and family must be aware of prior to treatment. An understanding of applications of the Taylor Spatial Frame gives orthopedic surgeons an extra tool to correct simple and complex deformities in pediatric and adolescent patients.