Aim and background:The introduction of the 'Vitruvian' Foot concept in 2019 established initial parameter measurements of the 'normal' foot quadrilateral (FQ) in the sagittal plane. This effort had been aimed at increasing precision when analysing alignment abnormalities in post-traumatic and congenital foot deformities, so as to more accurately guide corrective treatment planning with osteotomies. The current study enhances the prior, existing data with an expanded normal cohort. We also offer a case report that describes the successful application of the revised reference angles for our analysis and correction of a congenital foot deformity in a 29-year-old woman. Materials and methods:Included in the present analysis were 100 normal radiographs (78 patients). We followed the FQ delineated by our previous studies, which uses the distance between the posterior process of the talus and the anterior edge of the articular surface of the talus body (points a and b, respectively) to form the talus joint line (TJL). The FQ is then transcribed in the sagittal plane, anchored by the dual weight-bearing apices created by the junctures of the TJL and the most definitively plantar points of (1) the first metatarsal head (c) and (2) the posterior calcaneus (d). Reference angles were designated as: The anatomic lateral talometatarsal angle (aLTMA, ∠bcd), the mechanical talometatarsal angle (mLTMA, ∠bac), and the lateral heel angle (LHA, ∠acd). Additionally, we measured ∠dab, ∠abc, and ∠cda, as well as the proportional values of line lengths bc:ab (k1), cd:ab (k2), and ad:ab. Results:The resulting, revised measurements and standard deviations (SDs) were as follows: ∠abc = 144.5 ± 3.7 degrees, ∠bcd = 32.6 ± 1.9 degrees, ∠cda = 79.1 ± 3.7 degrees, ∠dab = 103.8 ± 3.4 degrees, k1 = 3.02 ± 0.24, k2 = 3.83 ± 0.31, and k3 = 1.62 ± 0.17. Conclusion:We expanded the dataset of previous publications and to corroborate and more accurately define upon the concept of the normalised 'Vitruvian' foot. The larger sample size allowed refinements in the previously established reference values. Though the newer calculations showed only slight referential changes, there was a noticeable tightening of the SD over the previously published reference lines and angles (RLAs) measurements. Clinical significance:The updated normalised parameters can offer the surgeon a reliable framework to enhance precision in foot deformity correction planning. Level of clinical evidence:III. How to cite this article:Solomin L, Ukhanov K, Kirienko A, et al. Enhanced Precision for Deformity Correction Planning: Revision of Values for the Vitruvian Foot Quadrilateral with Demonstrative Case Report. Strategies Trauma Limb Reconstr 2025;20(2):72-81.

BACKGROUND:The multiplier method is an arithmetic calculation that estimates the amount of growth remaining until skeletal maturity. When predicting lower limb length discrepancy, differences in foot height are added to femur and tibia discrepancies. Foot height multipliers have not been calculated using radiographic measurements, so it is unclear whether foot height develops at the same pace as the femur and tibia. This study used serial images to calculate foot height multipliers and compared them to published lower limb and foot length multipliers. METHODS:The Bolton Brush radiograph collection was used to measure foot height on the lateral foot view. Multipliers were calculated for ages with at least 10 serial study visits. 212 patients (2195 radiographs) were included in the study (102 female, 110 male patients). Foot height multipliers were calculated for ages 0 to 17 years (females) and 0 to 18 years (males). RESULTS:Multipliers decreased with age, but qualitatively plateau at age 13 (females) and age 15 (males). Lower extremity multipliers have a more dramatic growth curve, indicating comparatively greater lower extremity growth after birth. However, when comparing the limb length discrepancy calculation using the lower extremity multiplier versus the foot height multiplier for the foot portion, the difference was negligible. CONCLUSIONS:This paper provides a database of foot height multipliers. Foot height seems to grow on a different trajectory than other lower limb components, confirming that one should consider separate multiplier values. The difference created by the foot height multiplier versus the lower extremity multiplier appears to be modest. Separate use of the foot height multiplier may only be necessary for young children with large foot height discrepancies, but further study to confirm the lack of impact of the foot height multiplier on limb length discrepancy calculations is needed. Our data were derived from normal children, so it is unknown if the presence of a talo-calcaneal coalition would affect foot height on the involved side. LEVEL OF EVIDENCE:Level III-retrospective comparative study.

BACKGROUND:There has been historical concern that the use of intramedullary nails could present undue risk of osteonecrosis of the femoral head due to compromise of the femoral blood supply. Intramedullary lengthening nails are rapidly becoming commonplace in lengthening procedures. As such, the primary objective of this study was to analyze the rates of osteonecrosis following femoral lengthening. The secondary objective was to characterize general trends in femoral lengthening. METHODS:This retrospective cohort study evaluated patients who had undergone femoral lengthening at a single institution from 2012 to 2021. Retrospective chart review and radiographic evaluation of osteonecrosis were conducted. The primary end point was radiographic evidence of osteonecrosis. The secondary variables were the starting point of the femoral nail, the total amount of lengthening, and the time to consolidation. RESULTS:Two hundred and forty-seven patients were included in the analysis, including 111 males and 136 females, with a mean age of 17 years. No patient had radiographic evidence of osteonecrosis (0%) or coxa valga (0%). The average amount of lengthening was 4.88 cm (range, 1.5 to 8.5 cm). No patient had any extensive complications, such as alterations in the proximal femoral anatomy. CONCLUSIONS:This largest study to date investigating complications following femoral lengthening using intramedullary lengthening nails revealed that femoral lengthening is a well-tolerated procedure, and osteonecrosis is an infrequent complication. LEVEL OF EVIDENCE:Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background:Recently, limb lengthening devices have shifted from external fixators to telescoping magnetic intramedullary lengthening nails (MILNs), which lengthen strictly along the bone's anatomic axis. Baumgart proposed the reverse planning method, overcorrecting lateral shift with a distal osteotomy and slight varus angulation. The untested assumption that antegrade lengthening along the anatomic axis causes lateral mechanical axis deviation (MAD) prompted our study, which examines MILNs' effect on lower limb alignment. Methods:We retrospectively evaluated records for 154 femoral antegrade MILNs inserted in 122 adult patients for limb lengthening. We excluded patients who underwent concomitant corrective osteotomies or tibial lengthening, or who had malunion, nonunion, mechanical failure, or revision surgery for any reason. Long-leg standing radiographs were taken preoperatively, at the end of lengthening, around 3 months postoperatively, and at the culmination of consolidation (approximately 6 months postoperatively). MAD and anatomic mechanical angle (AMA) were assessed as primary outcomes at each radiographic time point for sequential comparison. The predicted MAD was derived from the trigonometric formula (Predicted MAD = lengthening × sin [AMA]). Results:Average preoperative MAD was 2.4 mm medial (SD = 10.6), diminishing to 1.9 mm medial (SD = 13.2) by the end of lengthening. On assessment at consolidation, average MAD had equilibrated back to 2.6 mm medial. Our results showed a net shift of 0.18 mm, whereas the predicted shift was 5.4 mm. The mean preoperative AMA was 5.9 mm (SD = 1.49). At the end of lengthening, the average AMA had decreased to 4.8 mm (SD = 1.4). Conclusion:Our data indicated minimal to no impact on the mechanical axis or joint alignment of the lower limb after antegrade lengthening using a telescoping femoral MILN in a deformity-free femur. Study results suggested that the femur typically realigned in a way that minimized mechanical deviation while preserving joint alignment. Level of Evidence:Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Magnetic intramedullary lengthening nails (MILNs) have become an increasingly popular method for long-bone distraction osteogenesis as a means of overcoming the limitations of bone lengthening with an external fixator. While factors such as nail diameter, alignment, and other mechanical characteristics have been associated with an increased risk of nail breakage, the relationship between the percentage of maximum lengthening utilized and nail breakage remains unexplored. We specifically assessed overall complications, with and without the inclusion of contractures, based on the amount of distraction (25% to 60%, 61% to 90%, and 91% to 100% of maximum). METHODS:We retrospectively reviewed the records for 176 pediatric patients and 109 adult patients who had undergone limb lengthening and had ≥24 months of follow-up. The cohort was further stratified by the amount of distraction: 25% to 60% (n = 75 children and 30 adults), 61% to 90% (n = 72 children and 29 adults), and 91% to 100% (n = 29 children and 50 adults). The mean ages were 14.53, 13.53, and 12.49 years, respectively, in the pediatric cohorts and 27.1, 34.3, and 23.8 years, respectively, in the adult cohorts. The percentages of males and females were 48% vs. 52%, 54.2% vs. 45.8%, and 48.3% vs 51.7%, respectively, in the pediatric cohorts and 56.7% vs. 43.3%, 51.8% vs. 48.2%, and 58% vs. 42% in the adult cohorts. Complications included contractures, loss of length, bone fracture, axial deviation, nail failure, failure to lengthen, nail fracture/failure, and screw failure. Analysis of variance (ANOVA) was conducted to compare mean complications across the 3 distraction categories, and Tukey pairwise t tests were performed to compare mean complications between individual distraction categories. RESULTS:Without contractures, complication rates were similar between the pediatric cohorts (p = 0.09): 4.0% (25% to 60% distraction), 13.9% (61% to 90% distraction), and 6.9% (91% to 100% distraction). With contractures included, complication rates were greatest in the 61% to 90% pediatric cohort (38.9%), followed by the 91% to 100% cohort (27.6%) and the 25% to 60% cohort (13.3%) (p = 0.002). Similarly, the adult population had a homogeneous rate of complications without the inclusion of contractures (p = 0.13). Likewise, we observed a similarly variable distribution with contractures considered, with the greatest frequency in the 91% to 100% group (36%), followed by the 61% to 90% group (31%) and the 25% to 60% group (10%) (p = 0.04). CONCLUSIONS:This is the first study to explore the relationship between the percentage of nail lengthening and nail complications. The speculation that full extension of the nail could lead to increased nail bending or breakage was not consistent with our findings. This finding was consistent whether contractures were included or not. LEVEL OF EVIDENCE:Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Accurate limb length measurement is essential during limb lengthening procedures to prevent neurologic and musculoskeletal complications. Magnetic intramedullary lengthening nails (MILN) rely on radiographs for measurement, but the optimal radiographic technique is not established. This study evaluated the precision and accuracy of EOS imaging versus digital radiography, including calibration techniques and measurement techniques for assessing intramedullary lengthening. An MILN was inserted into a Sawbones femur, and lengthening measurements from digital X-ray and EOS imaging were compared to external remote control (ERC) results. Measurements were taken with and without calibration using a magnification ball, nail width, or female nail length. Four observers measured the distraction gap, spindle length, full nail length, and male nail length at various hip flexion angles. Precision and accuracy were calculated for each technique. From 576 measurements, EOS imaging demonstrated significantly higher accuracy than digital radiography (83.6

Background: Effective postoperative pain management is essential in femoral limb lengthening surgery. Although regional nerve blocks reduce pain and opioid use, their benefit in antegrade femoral intramedullary limb lengthening is unclear. This study compares postoperative pain and opioid consumption in patients receiving general anesthesia (GA) alone versus GA with a preoperative femoral or fascia iliaca nerve block. Methods: A retrospective review included 192 patients who underwent femoral lengthening with intramedullary telescoping nails between January 2012 and October 2023 at a single center. Patients were categorized into Group A (GA alone, n = 131) and Group B (GA plus nerve block, n = 61). Primary outcomes were postoperative mean and maximum pain scores in the first 24 h, total opioid pills prescribed at discharge, and total morphine milligram equivalents (MMEs) used in the Post-Anesthesia Care Unit (PACU). Non-inferiority was defined by a margin of one standard deviation for pain scores and opioid usage. Results: Demographics were similar between groups. Maximum PACU pain scores were 3.8 for Group A and 3.3 for Group B (p > 0.05); mean pain scores were 2.1 and 1.9, respectively (p > 0.05). GA alone was non-inferior for pain control. However, total opioid pills prescribed at discharge were higher in Group A (23.2) than Group B (10) (p < 0.05). PACU MME usage was also higher in Group A (26 vs. 18.4 ± 15 mg, p < 0.05), though non-inferiority criteria were met. Conclusions: GA alone is non-inferior to GA with nerve block for postoperative pain management following antegrade femoral intramedullary limb lengthening. Although patients without a nerve block received more opioids at discharge, their pain control remained similarly effective. Given potential risks and the lack of clear pain reduction benefits, routine nerve block use may not be warranted. Decisions regarding nerve block application should be individualized, considering patient preferences, surgeon recommendations, and anesthesiologist input.

Previous studies have shown that subtrochanteric femoral fractures treated with intramedullary nails might lead to varus-procurvatum malalignment. Similar results have been reported when using antegrade intramedullary lengthening nails (ILNs). The purpose of our study is to examine if antegrade telescoping intramedullary lengthening nails lead to varus-procurvatum malalignment of the proximal femur and what are possible predictors of that shift. In this retrospective, single centre study, five surgeons performed 537 femoral ILN. 347 antegrade PRECICE nails were selected after applying exclusion criteria. The following exclusion criteria were applied, intentional angular deformity correction, retrograde femoral lengthening and concomitant tibial lengthening. After further exclusion criteria were applied, we retrospectively inspected 201 PRECICE nails inserted in 158 paediatric and adult patients (average age 19.9 years) that underwent IM nail limb lengthening. Follow-up was at least one year by which time all osteotomies were healed. Mean lengthening was 4.7 cm per lengthening surgery with some patients needing multiple lengthening for large discrepancies. Of the 201 nails, trochanteric entry was used in 127 procedures and piriformis entry was used in 74 of them. With pre-op Osteotomy Level Coefficient (OLC) of 0.3. The preoperative neck shaft angle (NSA) was significantly reduced from 130.6 to 127.4 degrees at the end of lengthening (P < 0.05). There was no discernible correlation between the OLC and change in NSA. The trochanteric entry point was associated with a greater tendency to reduce the NSA (Mdif = -4.1, SD = 6.5) as compared to the piriformis entry point (Mdif = -3, SD 6.4) (P < 0.05). No significant change in anatomic medial proximal femoral angle (aMPFA) was noted between pre- and postoperative time points, nor between trochanteric and piriformis entry groups. Our study investigated the risk of iatrogenic varus deformity of the proximal femur following intramedullary limb lengthening procedures. We identified the osteotomy site as the most significant risk factor for developing iatrogenic varus, while the nail insertion point did not significantly predict this complication, showing comparable results for both trochanteric and piriformis entry points. Additionally, our study is the first to identify a correlation between the level of osteotomy and coxa-valga correction. We hypothesize that a higher osteotomy level might be beneficial for patients undergoing limb lengthening who also present with coxa-valga deformity. IV.

» NF1 Link and Pathophysiology: Congenital pseudarthrosis of the tibia (CPT) is strongly associated with neurofibromatosis type 1 (NF1), where loss of normal NF1 gene function impairs bone formation and promotes fibrous hamartoma, resulting in recurrent tibial nonunion.» Classifications and Diagnostics: Multiple radiographic classifications (Andersen, Crawford, Boyd, Paley, etc.) guide clinical decision making, while newer imaging (magnetic resonance imaging, quantitative ultrasound) refines diagnosis and helps tailor interventions.» Treatment Modalities: Strategies range from nonoperative bracing (prefracture) to surgical approaches such as intramedullary rods (standard or telescopic), free vascularized fibular grafts, ring fixators (Ilizarov), and "cross-union" procedures-often combined with pharmacologic agents such as bone morphogenetic proteins (BMPs) or bisphosphonates.» Mixed Results With Pharmacologics: While rhBMP and bisphosphonates address bone catabolism and anabolism, neither agent alone has consistently succeeded in NF1-related CPT; combination regimens may offer better outcomes but require more robust research.» Future Directions: Ongoing studies explore early surgery (vs. waiting until age 2-3) and guided growth to address tibial bowing, molecular therapies (e.g., MAPK kinase and Src homology 2 containing protein tyrosine phosphatase 2 inhibitors), and refined fixation techniques. The management of CPT continues to evolve as genetic and cellular mechanisms become clearer.

Growth-plate (GP) injures in limbs and other sites can impair GP function and cause deceleration of bone growth, leading to progressive bone lengthening imbalance, deformities and/or physical discomfort, decreased motion and pain. At present, surgical interventions are the only means available to correct these conditions by suppressing the GP activity in the unaffected limb and/or other bones in the ipsilateral region. Here, we aimed to develop a pharmacologic treatment of GP growth imbalance that involves local application of nanoparticles (NP)-based controlled release of a selective retinoic acid nuclear receptor gamma (RARγ) agonist drug. When RARγ agonist-loaded NP were implanted near the medial and lateral sides of proximal tibial growth plate in juvenile C57BL/6J mice, the GP underwent involution and closure. Overall tibia length was shortened compared to the contralateral element implanted with drug-free control NP. Importantly, when the RARγ agonist NP were implanted on the lateral side only, the adjacent epiphysis tilted toward the lateral side, leading to apical angulation of the tibia. In contrast to the local selectivity of these responses, systemic administration of RARγ agonists led to GP closure at many sites, inhibiting skeletal growth over time. Agonists for RARα and RARβ elicited no obvious responses over parallel regimens. Our findings provide novel evidence that RARγ agonist-loaded NP can control activity, function and directionality of a targeted GP, offering a potential and clinically-relevant alternative or supplementation to surgical correction of limb length discrepancy and angular deformities.

INTRODUCTION:Limb-length discrepancies (LLDs) have traditionally been treated with external fixators, but magnetically driven intramedullary nails (MILNs) are increasingly favored for improved comfort and reduced infection risk. This study compared intramedullary (IM) versus extramedullary (EM) lengthening nails in pediatric patients with narrow femoral canals to evaluate mechanical axis deviation, nail bending, tourniquet time, and complications. METHODS:A retrospective, single-center review was conducted of 75 pediatric patients who underwent femoral lengthening between 2015 and 2022, each with at least two years of follow-up. Patients received either an 8.5 mm IM nail or a 10.7/12.5 mm EM nail, combined with a solid, threaded IM nail for stability. Outcomes included preoperative and postoperative limb alignment (MAD, mLDFA, and mPDFA), IM nail bending, operative details (tourniquet time and blood loss), consolidation times, and complication rates classified according to the Cherkashin system. RESULTS:Forty-two patients were treated with EM nails and 33 with IM nails. Both groups achieved similar distraction amounts (4.7 ± 1.1 cm) and consolidation intervals (7 to 8 mo). However, the EM group demonstrated significantly greater postoperative MAD (12.9 ± 9.5 mm vs.  8.7 ± 7.3 mm, P  <0.05), higher nail bending (2 vs.  1.2 degrees, P <0.05), and longer tourniquet use. Overall complication rates were 69% (EM) and 60% (IM), with delayed union and soft tissue infection being the most frequent issues. Unplanned reoperations occurred in 21% of patients overall. CONCLUSION:Both nail types correct limb‑length discrepancy, but extramedullary nails demand longer tourniquet times and have higher bending (of the IM component of the EM construct) and complication rates. Implant choice must suit patient factors and further comparative studies are warranted.

Background: Magnetic intramedullary lengthening nails (MILNs) have become an increasingly popular method for long-bone distraction osteogenesis as a means of overcoming the limitations of bone lengthening with an external fixator. While factors such as nail diameter, alignment, and other mechanical characteristics have been associated with an increased risk of nail breakage, the relationship between the percentage of maximum lengthening utilized and nail breakage remains unexplored. We specifically assessed overall complications, with and without the inclusion of contractures, based on the amount of distraction (25% to 60%, 61% to 90%, and 91% to 100% of maximum). Methods: We retrospectively reviewed the records for 176 pediatric patients and 109 adult patients who had undergone limb lengthening and had ≥24 months of follow-up. The cohort was further stratified by the amount of distraction: 25% to 60% (n = 75 children and 30 adults), 61% to 90% (n = 72 children and 29 adults), and 91% to 100% (n = 29 children and 50 adults). The mean ages were 14.53, 13.53, and 12.49 years, respectively, in the pediatric cohorts and 27.1, 34.3, and 23.8 years, respectively, in the adult cohorts. The percentages of males and females were 48% vs. 52%, 54.2% vs. 45.8%, and 48.3% vs 51.7%, respectively, in the pediatric cohorts and 56.7% vs. 43.3%, 51.8% vs. 48.2%, and 58% vs. 42% in the adult cohorts. Complications included contractures, loss of length, bone fracture, axial deviation, nail failure, failure to lengthen, nail fracture/failure, and screw failure. Analysis of variance (ANOVA) was conducted to compare mean complications across the 3 distraction categories, and Tukey pairwise t tests were performed to compare mean complications between individual distraction categories. Results: Without contractures, complication rates were similar between the pediatric cohorts (p = 0.09): 4.0% (25% to 60% distraction), 13.9% (61% to 90% distraction), and 6.9% (91% to 100% distraction). With contractures included, complication rates were greatest in the 61% to 90% pediatric cohort (38.9%), followed by the 91% to 100% cohort (27.6%) and the 25% to 60% cohort (13.3%) (p = 0.002). Similarly, the adult population had a homogeneous rate of complications without the inclusion of contractures (p = 0.13). Likewise, we observed a similarly variable distribution with contractures considered, with the greatest frequency in the 91% to 100% group (36%), followed by the 61% to 90% group (31%) and the 25% to 60% group (10%) (p = 0.04). Conclusions: This is the first study to explore the relationship between the percentage of nail lengthening and nail complications. The speculation that full extension of the nail could lead to increased nail bending or breakage was not consistent with our findings. This finding was consistent whether contractures were included or not. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Introduction:Surgical site infection (SSI) related to magnetic intramedullary lengthening nails (MILNs) can lead to delayed consolidation or loss of limb function, resulting in deleterious effects to a patient's quality of life. With the rise of MILNs, we sought to determine the incidence rate and risk factors for infection during limb lengthening with MILNs. Methods:We reviewed a consecutive series of patients who underwent femoral and/or tibial lengthening with an MILN at a single institution between 2012 and 2020 (n = 420). SSI was defined according to CDC-NHSN criteria (including superficial and deep infections) with postoperative surveillance time of 12 months. Demographic, health metrics, comorbidities, limb- and surgery-related factors, were assessed as potential risk mediators of SSI. Results:Incidence of SSI was 3.3 % (14/420). This was divided into superficial (0.5 %,2/420) and deep (2.9 %, 12/420) infections. Of deep infections, 75 % (9/12) were osteomyelitis. Of the 14 limbs that developed SSI, 57 % (8/14) had a history of prior external fixation in the same limb and 38 % (5/14) had a previous infection of the same limb. A subanalysis of patients with a history of prior external fixation in the same bone was associated with SSI, as compared to those without previous external fixation. None of the surgery-related infection risk factors reached statistical significance. Discussion and conclusion:The total incidence of infection with MILNs was 3.3 % at 24 months follow-up. The risk of deep infection was 2.9 %. Patients with a history of previous external fixation and prior infection show an independent association with increased rate of infection recurrence in the same bone. These patients could be considered a high-risk group for developing deep tissue infection. Potential algorithms include prolonged oral antibiotics after MILN insertion or simultaneous injection of absorbable antibiotic at the time of the nail insertion.

The actions of the retinoic acid nuclear receptor gamma (RARγ) agonist, palovarotene, on pre-existing osteochondromas were investigated using a mouse multiple osteochondroma model. This approach was based on the knowledge that patients often present to the clinic after realizing the existence of osteochondroma masses, and the findings from preclinical investigations are the effects of drugs on the initial formation of osteochondromas. Systemic administration of palovarotene, with increased doses (from 1.76 to 4.0 mg/kg) over time, fully inhibited tumor growth, keeping the tumor size (0.31 ± 0.049 mm3) similar to the initial size (0.27 ± 0.031 mm3, p = 0.66) while the control group tumor grew (1.03 ± 0.23 mm3, p = 0.023 to the drug-treated group). Nanoparticle (NP)-based local delivery of the RARγ agonist also inhibited the growth of osteochondromas at an early stage (Control: 0.52 ± 0.11 mm3; NP: 0.26 ± 0.10, p = 0.008). Transcriptome analysis revealed that the osteoarthritis pathway was activated in cultured chondrocytes treated with palovarotene (Z-score = 2.29), with the upregulation of matrix catabolic genes and the downregulation of matrix anabolic genes, consistent with the histology of palovarotene-treated osteochondromas. A reporter assay performed in cultured chondrocytes demonstrated that the Stat3 pathway, but not the Stat1/2 pathway, was stimulated by RARγ agonists. The activation of Stat3 by palovarotene was confirmed using immunoblotting and immunohistochemistry. These findings suggest that palovarotene treatment is effective against pre-existing osteochondromas and that the Stat3 pathway is involved in the antitumor actions of palovarotene.

Background: Limb lengthening procedures are performed for various indications, including limb length discrepancies (LLDs) and short stature. This systematic review and meta-analysis compares the efficacy and safety of the newer motorized intramedullary lengthening nails (MILNs) with the traditional alternative techniques (ATs) for femoral limb lengthening. Methods: We conducted a comprehensive literature search in the Medline, Embase, Cochrane, Web of Science, and Scopus databases, inclusive of all dates through July 1, 2023, and without language restrictions. Factors mediating outcomes included problems, obstacles, complications, total adverse events, healing/consolidation index, time to full weight-bearing, lengthening accuracy, percentage of lengthening goal achieved, and duration of hospital stay. Effect sizes were quantified using STATA 17.0. Statistical algorithms employed were random effects model standardized mean differences (SMDs) for continuous outcomes and log risk ratios (RRs) for dichotomous outcomes, both with 95% confidence intervals (CIs). Results: Our meta-analysis included 10 studies comparing MILN with AT: 180 femurs in the MILN group and 160 femurs in the AT group. This was exclusively comprised of retrospective cohort studies. When compared with AT, limb lengthening procedures utilizing MILNs had significantly lower problems (log RR, −1.35; 95% CI, −1.93 to −0.77; p < 0.001), complications (log RR, −0.56; 95% CI, −0.90 to −0.22; p = 0.001), and total adverse events (log RR, −0.69; 95% CI, −1.17 to −0.21; p = 0.005), as well as a superior bone healing index (SMD, −0.80; 95% CI, −1.32 to −0.28; p = 0.003). However, no significant differences were found in obstacles, percentage of lengthening goal achieved, lengthening accuracy, time to full weight-bearing, and duration of hospital stay. Conclusion: Limb lengthening with MILNs vs. AT may offer more favorable patient outcomes, lowering risk for problems, complications, and total adverse events, while optimizing the bone healing/consolidation index. However, the limitation of nonrandomized retrospective studies and high heterogeneity should be acknowledged. Level of Evidence: Level II (meta-analysis of cohort studies). See Instructions for Authors for a complete description of levels of evidence.

Distraction osteogenesis describes the process of growing new bone ("regenerate") to correct limb length discrepancies or limb deformities. Whether pure lengthening or a combination of lengthening and straightening is involved, this represents one of the highest anabolic demands on bone in orthopedic surgery. Because distraction osteogenesis requires the formation of new bone, often in large amounts, it is critically important to evaluate the bone health of any potential surgical patient. Patients undergoing limb lengthening, therefore, would be expected to be especially sensitive to poor bone health. This article will review opportunities to assess and potentially improve bone health for limb lengthening patients. Key Concepts:(1)Many potential limb lengthening patients may be vitamin D deficient or insufficient.(2)Other simple nutraceuticals such as Boron, Magnesium, Calcium, Silicon, vitamin K, L-arginine, and Inositol should be considered as adjuncts to bone health.(3)Intra-operative technique such as minimally invasive incisions that protect the blood supply and periosteum combined with osteotomies that maximize the bone surface area are recommended.(4)Numerous proposed pharmacological and mechanical interventions to improve and accelerate the healing of the regenerate bone look promising but are still investigational.

Pin tract infections are virtually universal complications with the use of external fixation. While most are superficial and respond to oral antibiotics and local care, septic loosening may occur at the bone-pin interface, which may lead to instability of the fixator, catastrophic failure, fracture, and long-term osteomyelitis. Classification systems and prevention protocols have been developed to address this ubiquitous complication. Treatment of severe pin tract infections often requires debridement, parenteral antibiotics, and removal of the offending pin or the entire external fixator. In cases of osteomyelitic pin tracks, a sizable cavity is often present. We describe a simple technique for treatment of deep bone pin tract infection through the use of debridement, irrigation, and an antibiotic "sparkler," which is a specially prepared percutaneous implant of antibiotic laden bone cement.Levels of Evidence: Level 5.

BACKGROUND:Limb lengthening procedures are performed for various indications, including limb length discrepancies (LLDs) and short stature. This systematic review and meta-analysis compares the efficacy and safety of the newer motorized intramedullary lengthening nails (MILNs) with the traditional alternative techniques (ATs) for femoral limb lengthening. METHODS:We conducted a comprehensive literature search in the Medline, Embase, Cochrane, Web of Science, and Scopus databases, inclusive of all dates through July 1, 2023, and without language restrictions. Factors mediating outcomes included problems, obstacles, complications, total adverse events, healing/consolidation index, time to full weight-bearing, lengthening accuracy, percentage of lengthening goal achieved, and duration of hospital stay. Effect sizes were quantified using STATA 17.0. Statistical algorithms employed were random effects model standardized mean differences (SMDs) for continuous outcomes and log risk ratios (RRs) for dichotomous outcomes, both with 95% confidence intervals (CIs). RESULTS:Our meta-analysis included 10 studies comparing MILN with AT: 180 femurs in the MILN group and 160 femurs in the AT group. This was exclusively comprised of retrospective cohort studies. When compared with AT, limb lengthening procedures utilizing MILNs had significantly lower problems (log RR, -1.35; 95% CI, -1.93 to -0.77; p < 0.001), complications (log RR, -0.56; 95% CI, -0.90 to -0.22; p = 0.001), and total adverse events (log RR, -0.69; 95% CI, -1.17 to -0.21; p = 0.005), as well as a superior bone healing index (SMD, -0.80; 95% CI, -1.32 to -0.28; p = 0.003). However, no significant differences were found in obstacles, percentage of lengthening goal achieved, lengthening accuracy, time to full weight-bearing, and duration of hospital stay. CONCLUSION:Limb lengthening with MILNs vs. AT may offer more favorable patient outcomes, lowering risk for problems, complications, and total adverse events, while optimizing the bone healing/consolidation index. However, the limitation of nonrandomized retrospective studies and high heterogeneity should be acknowledged. LEVEL OF EVIDENCE:Level II (meta-analysis of cohort studies). See Instructions for Authors for a complete description of levels of evidence.