Antegrade femoral lengthening and simultaneous hemiepiphysiodesis for congenital femoral deficiency.

Purpose: Congenital femoral deficiency is characterized by limb length discrepancy and genu valgum. Lengthening of the femur along its anatomic axis increases valgus alignment by medial knee translation. Pairing limb lengthening with simultaneous medial distal femoral hemiepiphysiodesis can simultaneously correct two limb deformities. Methods: All skeletally immature patients with congenital femoral deficiency who underwent antegrade femoral lengthening and concomitant guided growth over a 4-year period were reviewed. Length and alignment data were quantified during lengthening, consolidation, and for 1 year after guided growth implants were removed or the patient reached skeletal maturity. Digital simulation was performed for all lengthenings to assess the mechanical alignment that would have been achieved had lengthening been performed without medial distal femoral hemiepiphysiodesis. Results: Nine patients (five males, four females, mean age = 12.3 ± 1.9 years) underwent 10 antegrade intramedullary femoral lengthenings with simultaneous medial distal femoral hemiepiphysiodesis. All had improvement in valgus alignment (average improvement in mechanical axis deviation was 18 ± 11 mm, average change in limb alignment was 6 ± 5°). In simulated lengthenings without guided growth, all limbs would have experienced increased lateral mechanical axis deviation of 5 ± 3 mm. The hemiepiphysiodesis implant and lengthening device were explanted simultaneously in 7 of 10 lengthenings. Conclusion: Simultaneous medial distal femoral hemiepiphysiodesis with antegrade femoral lengthening for ongenital femoral deficiency can minimize the number of surgical episodes for the skeletally immature patient. The lengthening device and guided growth construct can be removed simultaneously in a majority of cases, saving children one or two additional surgical treatments.

Proximal Tibial Recurvatum-Valgus: Analysis and Treatment.

Genu recurvatum-valgus arises from the proximal tibia and poses challenges in its treatment. The etiology of the combined deformities can include physeal trauma (often unrecognized), iatrogenic injury, infection, tumor, Osgood-Schlatter syndrome, skeletal dysplasia, and ligamentous laxity. Both osseous and ligamentous contributions must be recognized for successful treatment. A graphical planning method identifies the true (oblique) plane of deformity. Surgical treatment options include epiphysiodesis to prevent progressive deformity, guided growth, opening-wedge proximal tibial osteotomy, and gradual correction with concomitant limb lengthening using external fixation or motorized internal lengthening. Opening-wedge proximal tibial osteotomy conducted along the true deformity plane is a reliable surgical method for lesser-magnitude deformities. Gradual correction using circular external fixation is considered when the magnitude of correction is greater than 25º or when limb shortening and/or multiplanar deformity is present. After successful surgical management, patients can expect to achieve correction of knee hyperextension, posterior tibial slope, and mechanical axis. Restoration of these parameters re-establishes physiologic loading of the knee. This review illustrates the clinical and radiographic assessment of the deformity, relevant anatomy, and five surgical techniques for the genu recurvatum-valgus deformity of the proximal tibia.

Re-use of Motorised Intramedullary Limb Lengthening Nails.

Aim: This study reviews the re-use of implanted motorised intramedullary lengthening nails previously used for limb lengthening. Materials and methods: A retrospective review was performed on the re-use of motorised intramedullary lengthening nails. All patients had a magnetically controlled intramedullary lengthening nail in the femur, tibia, or humerus previously utilised for either lengthening or compression. Patients were included if the magnetically controlled intramedullary lengthening nail underwent attempted re-use either in the same lengthening episode or in a temporally separate lengthening treatment requiring another corticotomy. Results: Ten patients with 12 lengthening episodes were analysed including five tibial, five femoral and two humeral segments. Overall, seven of 12 nails (58%) were successfully re-deployed without the need for nail exchange. Two of three nails were successfully retracted and re-used for continued distraction in the same lengthening treatment. Five of nine nails (56%) were successfully reactivated in a subsequent, later lengthening episode. Conclusion: Re-use of a magnetically controlled limb lengthening nail is an off-label technique that may be considered for patients requiring ongoing or later lengthening of the femur, tibia or humerus. Regardless of whether the nail is used in the same lengthening episode or separate lengthening episode, surgeons should be prepared for exchange to a new implant. Clinical significance: Re-use of a magnetically controlled intramedullary lengthening nail will reduce surgical trauma and save implant cost in limb lengthening treatment but may only be possible in half of attempted cases. How to cite this article: Georgiadis AG, Nahm NJ, Dahl MT. Re-use of Motorised Intramedullary Limb Lengthening Nails. Strategies Trauma Limb Reconstr 2023;18(2):106-110.

Reduction of High Hip Dislocation With a Distraction Nail and Arthroplasty (Preliminary Results of a Novel Technique).

A novel distraction technique is described for total hip arthroplasty in symptomatic high hip dislocation (Crowe IV) combining an intramedullary motorized lengthening nail with a pelvic support plate to gradually stretch hip soft tissues (distalization) and performing total hip arthroplasty with the cup in the primary acetabulum. Twelve patients (15 hips) were identified in a retrospective study via chart review. Medical records and radiographs were reviewed for details of the initial case parameters, surgical details, magnitude of distalization, duration of treatment, outcomes, and complications. Followed by an average of 67.4 mm of distalization, nearly anatomical cup placement, and equal leg length were achieved in all patients. During distalization, pain level was low with acceptable range of motion. One unplanned surgery and no complications with long-term sequelae occurred.

Motorized Plate Lengthening of the Femur in Children: A Preliminary Report.

BACKGROUND: Limb lengthening by distraction osteogenesis can be performed with motorized internal devices, but intramedullary implants risk avascular necrosis of the femoral head in young children. A method of internal limb lengthening using a motorized expandable plate has been developed and preliminary results are presented. METHODS: Seven skeletally immature patients (ages 2.7 to 9.7 y) with congenital femoral deficiencies underwent femoral lengthening with the use of a magnetic expandable plate. Surgical details, lengthening parameters, Limb Lengthening and Reconstruction Society-Angular deformity, Infection, Motion index, and complications were reviewed and classified according to the modified Clavien-Dindo system. RESULTS: An average lengthening was 4.1 cm (range, 3.3 to 4.4 cm) comprising 18% of initial femoral segment length (range, 14% to 21%). The average lengthening phase was 50.2 days (range, 40 to 57 d) and weight-bearing was initiated at an average of 13 weeks from surgery (range, 8 to 18 wk). Limb deformities and length discrepancies were of moderate complexity, with an Limb Lengthening and Reconstruction Society-Angular deformity, Infection, Motion score of 6.57 (range, 6 to 7). Complication rates were comparable to previously reported methods of femoral lengthening. One patient underwent reoperation for patellar instability and 1 patient experienced radiographic hip subluxation which was observed. Small magnitude varus was observed in regenerate in 3 of 7 cases, none requiring treatment. Preoperative planning consisted of careful localization of the corticotomy site, acute deformity correction at the lengthening site in 3 cases, and implant orientation. CONCLUSIONS: Limb lengthening with motorized internal plates is feasible for young children with congenital femoral deficiency for whom intramedullary lengthening is unsafe or if external fixation is to be avoided. However, the fundamental principles of distraction osteogenesis and risks of lengthening for congenital discrepancies remain unchanged. Specific considerations herein include: careful planning of implant length and positioning, adjacent joint protection with adjunctive means, and mitigating deformity of the regenerate during distraction. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Segmental Bone Defects and the History of Bone Transport.

SUMMARY: This article describes the etiology of segmental bone defects and reviews the options of care, past and present. A brief description of distraction osteogenesis and how the Ilizarov method was used to treat bone defects with circular external fixation leading to the latest method of transport with motorized internal lengthening nails is presented.

Distal Tibial Guided Growth for Anterolateral Bowing of the Tibia: Fracture May Be Prevented.

BACKGROUND: Congenital pseudarthrosis of the tibia is a rare and challenging pediatric condition. The pre-fracture state, called congenital tibial dysplasia or anterolateral bowing of the tibia, presents a high fracture risk due to underlying bowing and dysplasia. After fracture, there is a substantial risk of nonunion. Any union achieved may be complicated by refracture, deformity, leg-length discrepancy, stiffness, pain, and dysfunction. We present the results of using distal tibial growth modulation to improve tibial alignment and to decrease fracture risk in this condition. To our knowledge, this is the first report of isolated distal tibial growth modulation as the primary surgical treatment for this condition. METHODS: This is a retrospective study of 10 patients with congenital tibial dysplasia who presented prior to pseudarthrosis and underwent distal tibial growth modulation as a primary treatment. The medical records and radiographs were reviewed for age at the times of diagnosis and treatment, fracture, secondary procedures, complications, residual deformity, cystic changes, and leg-length discrepancy. RESULTS: Ten patients had a mean follow-up (and standard deviation) of 5.1 ± 1.9 years. No patient sustained a tibial fracture, and no patient developed a tibial pseudarthrosis after guided growth was initiated. The mean age at the initiation of growth modulation was 2.6 ± 1.3 years. Six patients required a plate exchange. The mean residual tibial diaphyseal angular deformity at the most recent follow-up was 4.3° ± 3.2° of varus and 8.4° ± 5.8° in the sagittal plane. Only 1 patient had a clinically important leg-length discrepancy, with the affected leg being longer. CONCLUSIONS: In this series of 10 patients with congenital tibial dysplasia, distal tibial growth modulation delayed or possibly prevented fracture, decreased tibial malalignment, improved radiographic appearance of bone quality, and preserved leg length. No patient developed tibial fracture or pseudarthrosis after the initiation of guided growth treatment. Although early results are promising, follow-up to maturity is required to define the exact role of this simple outpatient procedure in congenital tibial dysplasia. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Extramedullary Motorized Lengthening of the Femur in Young Children.

BACKGROUND: Limb lengthening by distraction osteogenesis is now achievable via motorized intramedullary devices, mitigating many complications of lengthening by external fixation. In young patients, antegrade intramedullary nailing of the femur risks avascular necrosis of the femoral head. A method of extramedullary placement of a motorized expandable intramedullary nail has been employed by the senior author to safely achieve femoral lengthening without the use of an external fixator in young patients. METHODS: Eleven skeletally immature patients with lower limb length discrepancy were reviewed who underwent extramedullary placement of a magnetic, expandable intramedullary nail for lengthening of the femur. Surgical details, lengthening parameters, and complications were reviewed and classified according to the modified Clavien-Dindo Classification. RESULTS: Average lengthening was 32.3 mm (range: 27 to 40 mm) comprising an average 14.8% of femoral segment length. The average lengthening duration was 6.3 weeks, and average full weight-bearing began at 12.6 weeks. All but 1 patient underwent early removal of the device at an average of 4.5 months, and 5 had immediate plating of the femur. Complications rates were comparable to other methods of femoral lengthening, including varus or procurvatum through the regenerate, and unplanned reoperation in 3 of 11 cases. Preoperative considerations included careful planning of implant length due to short femoral segments and protection of the knee joint from contracture or iatrogenic instability. CONCLUSIONS: Extramedullary placement of a magnetic expandable intramedullary lengthening nail can achieve lengthening of the femur without the use of external fixation. Considerations with this technique include careful planning of implant length relative to trochanteric-physeal distance, protection against knee subluxation during lengthening, and mitigating deformity of the regenerate. Off-label, extramedullary use of these devices can be considered to decrease the burdens of external fixation in young children. The technique begs the advent of future all-internal technology specifically designed for safe limb lengthening in this age group. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Lengthening of the Humerus Using a Motorized Lengthening Nail: A Retrospective Comparative Series.

BACKGROUND: Lengthening of the humerus has traditionally been accomplished by the use of external fixation. Intramedullary motorized lengthening nails are now frequently used for lower limb lengthening, and this technology is slowly being adopted for use in the humerus. METHODS: A retrospective, single-surgeon experience of pediatric humeral lengthenings was performed. The time period surveyed included use of external fixation (EF) for lengthening, and the use of a motorized nail (MN) for lengthening. The primary outcome measures were lengthening magnitude achieved, duration of lengthening, frequency and type of complications encountered, or further procedures required, during each lengthening. RESULTS: From 1999 to 2018, 13 humeral lengthenings were performed in 9 patients. Six lengthenings were performed using the MN technique and 7 using the EF technique. The average absolute lengthening achieved was 8.5±1.3 cm in the EF group and 6.6±2.3 cm in the MN group. The duration of lengthening averaged 114 days in the MN group and 103 days in the EF group. The average duration of EF time was 215 days. Two patients underwent an initial EF lengthening of a humerus and then underwent a second lengthening using the MN technique. Two of 6 (33%) MN lengthenings and 3 of 7 (43%) EF lengthenings experienced complications during treatment. Two patients in the MN group underwent planned reversal and redeployment of their motorized nails to attain the planned lengthening magnitude. CONCLUSIONS: Humeral lengthening using motorized intramedullary nails is a safe technique that mitigates some of the complications of EF including pin site infection. It is well tolerated by patients. For lengthenings of a large magnitude, reversal and reuse of MN can be considered.

Complications of Limb Lengthening With Motorized Intramedullary Nails.

Intramedullary limb lengthening (LL) is now achievable through motorized intramedullary devices. While this technology mitigates some complications of external-fixation-based lengthening, many complications common to all lengthening procedures persist. New challenges and complications exclusive to this newer technology are also presented. The LL surgeon should be aware of and ready to respond to complications involving device malfunctions, poor local bony and soft-tissue biology, patient compliance, neurovascular compromise, joint instability, regenerate problems, and others. While technology will continue to evolve, study of and adherence to foundational principles of LL will minimize risks and optimize patient outcomes.

Management of a Broken PRECICE Femoral Nail at an Ununited Distraction Osteogenesis Site: A Case Report.

CASE: A 20-year-old man with a history of right lower extremity fibular hemimelia previously treated with PRECICE femoral nail lengthening presented with a broken magnetic nail and a displaced fracture through an ununited distraction osteogenesis site. Using a combination of techniques, we removed the broken implant while maintaining the achieved limb length and preserving the native biology without bone grafting. CONCLUSION: The unique challenges associated with the removal of a broken PRECICE femoral nail are described, with a technique for implant removal that preserves the achieved length, the innate biology of the distraction osteogenesis site, and promoting union without bone grafting.

What Factors Influence Union and Refracture of Congenital Pseudarthrosis of the Tibia? A Multicenter Long-term Study.

OBJECTIVE: To identify factors influencing union of congenital pseudarthrosis of the tibia (CPT), refractures, and integrity of the tibia at maturity. METHODS: Data of 119 children operated for Crawford-type IV CPT and followed-up till skeletal maturity were analyzed. Logistic regression and recursive partitioning analyses were used to test associations between several variables and the outcome. RESULTS: Primary union occurred in 86% of children. At maturity, 69% remained soundly united. The odds ratio for failure of primary union was 3.89 (95% confidence interval, 1.05-14.40; P=0.042) when bone morphogenetic protein was used, and children who had a combination of the Ilizarov technique and intramedullary nailing were at risk for unsound union at maturity (odds ratio, 6.19; 95% confidence interval, 1.24-30.83; P=0.026). No other association reached statistical significance. On recursive partitioning, use of the Ilizarov technique, transfixing the ankle and subtalar joints, use of cortical graft and not operating on the fibula were associated with a better outcome; use of bone morphogenetic protein and combining intramedullary nailing with the Ilizarov technique were associated with poor results. CONCLUSIONS: A larger sample is needed to confirm which factors truly influence the outcome of CPT. This may be feasible if data are collected prospectively through a multicenter registry.

Plate-assisted Lengthening of the Femur and Tibia in Pediatric Patients.

BACKGROUND: Limb lengthening over a percutaneous plate can be used during pediatric distraction osteogenesis to decrease the time of external fixation. METHODS: A retrospective, consecutive 2-surgeon experience of pediatric femoral and tibial lengthenings with a plate-assisted lengthening (PAL) technique was performed. The plate was placed at the time of index corticotomy. The primary outcome measures of external fixation index, consolidation index, and complications were assessed for each lengthening. RESULTS: From 2005 to 2012, 38 lengthenings (23 femur, 15 tibia) in 30 patients were performed by a PAL technique. All patients experienced successful distraction and consolidation. The average achieved lengthening was 3.80±0.98 cm (range, 2.2 to 6.4) with an average consolidation index of 27 days/cm and a mean external fixation index of 13.1±4.29 days/cm (range, 7.8 to 30). Patients returned to full weight-bearing activity after an average of 98.3±28.5 days. There were an average of 1.08±1.05 total complications and 0.39±0.75 severe complications per lengthening. Complications were encountered most commonly during femoral lengthening, including procurvatum and varus deformity through the regenerate. These deformities were usually corrected by frame adjustment before removal. CONCLUSIONS: PAL is a safe technique that minimizes time of external fixation, accelerates rehabilitation and weight-bearing, and can be successfully used on the femur or tibia. The most common complications are angular deformities of the regenerate that can be treated with adjustment before or at the time of plate locking. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Eosinophil-dependent skin innervation and itching following contact toxicant exposure in mice.

BACKGROUND: Contact toxicant reactions are accompanied by localized skin inflammation and concomitant increases in site-specific itch responses. The role(s) of eosinophils in these reactions is poorly understood. However, previous studies have suggested that localized eosinophil-nerve interactions at sites of inflammation significantly alter tissue innervation. OBJECTIVE: To define a potential mechanistic link between eosinophils and neurosensory responses in the skin leading to itching. METHODS: BALB/cJ mice were exposed to different contact toxicants, identifying trimellitic anhydride (TMA) for further study on the basis of inducing a robust eosinophilia accompanied by degranulation. Subsequent studies using TMA were performed with wild type versus eosinophil-deficient PHIL mice, assessing edematous responses and remodeling events such as sensory nerve innervation of the skin and induced pathophysiological responses (ie, itching). RESULTS: Exposure to TMA, but not dinitrofluorobenzene, resulted in a robust eosinophil skin infiltrate accompanied by significant levels of degranulation. Follow-up studies using TMA with wild type versus eosinophil-deficient PHIL mice showed that the induced edematous responses and histopathology were, in part, causatively linked with the presence of eosinophils. Significantly, these data also demonstrated that eosinophil-mediated events correlated with a significant increase in substance P content of the cutaneous nerves and an accompanying increase in itching, both of which were abolished in the absence of eosinophils. CONCLUSIONS: Eosinophil-mediated events following TMA contact toxicant reactions increase skin sensory nerve substance P and, in turn, increase itching responses. Thus, eosinophil-nerve interactions provide a potential mechanistic link between eosinophil-mediated events and neurosensory responses following exposure to some contact toxicants.

Motorized intramedullary nail for management of limb-length discrepancy and deformity.

Distraction osteogenesis has been used for more than 50 years to address limb-length discrepancy and deformity. Intramedullary fixation has been used in conjunction with external fixation to decrease the time in the external fixator and prevent deformity and refracture. A new generation of motorized intramedullary nails is now available to treat limb-length discrepancy and deformity. These nails provide bone fragment stabilization and lengthening with reliable remote-controlled mechanisms, obviating the need for external fixation. Motorized intramedullary nails allow accurate, well-controlled distraction, and early clinical results have been positive.