Femoral Lengthening Research Articles

Limb lengthening of a rare case of congenital femoral deficiency with an unstable knee

Congenital femoral deficiency (CFD) is a rare birth defect that is characterized by a short femur, associated with hip and knee deformity, deficiency, or instability. Children with severe CFD may need multiple deformity correction or lengthening procedures to reduce axial malalignment and limb length discrepancy (LLD). During limb lengthening, it can occur knee subluxation or dislocation, a severe treatment-related complication. We report a 15-year-old girl with a CFD with a previous episode of posterior subluxation of the knee during a femoral lengthening using a monolateral external fixator. She had a 13 cm LLD and coxa vara; therefore, it was applied a knee spanning Ilizarov fixator with a double osteotomy of the femur for gradual correction. At 11 months following Ilizarov application, a complete correction was achieved, and the circular fixator was removed. Knee joints of patients with CFD show highly variable grades of instability. Adequate surgical techniques, preventive measures, and early detection of signs of subluxation can lead to good functional results. Femur lengthening with a preventive bridging of the knee with an Ilizarov frame is a safe and effective way of treating patients with CFD.

Bifocal femoral lengthening with intramedullary magnetic lengthening nail following osteotomy propagation

Techniques in limb lengthening have evolved since the early 1900s. The external fixation using an Ilizarov frame was the current gold standard. Recently, intramedullary devices have been utilized in limb lengthening procedures to avoid complications related to the bulky external fixators. Here, we present the case of a 41-year-old female with long-term limb length discrepancy (LLD) corrected with magnetically driven intramedullary nailing. An intraoperative fracture of the distal femur led to bifocal lengthening at both the osteotomy site and the fracture site. This case cautioned the orthopedic surgeons involved in limb lengthening surgery about potential complications that can happen during the procedure. It demonstrated the possible efficacy of bifocal lengthening procedures using a magnetically driven intramedullary nail in the setting of complex LLD.

Bifocal Femoral Lengthening with Intramedullary Magnetic Lengthening Nail Following Osteotomy Propagation

Bifocal Femoral Lengthening with Intramedullary Magnetic Lengthening Nail Following Osteotomy Propagation

Thromboprophylaxis in Intramedullary Limb Lengthening Surgery.

AimThe use of intramedullary lengthening devices is becoming increasingly popular. There are limited data regarding the incidence of venous thromboembolism following intramedullary lengthening surgery and no reports or guidance for current practice on use of thromboprophylaxis. Following a case of post-operative deep vein thrombosis in our institution, we felt that it is important to assess best practice. We conducted a national survey to collect data that would describe current practice and help develop consensus for treatment.Materials and methodsWe identified surgeons across the UK that perform adult intramedullary limb lengthening through the British Limb Reconstruction Society membership and a Precise Users database. Surgeons were contacted and asked to respond to an online survey. Responses to thromboprophylaxis regimes employed in their practice and cases of venous thromboembolism were collated.Results24 out of 54 surgeons identified responded with a total of 454 cases of adult intramedullary lengthening (352 femoral and 102 tibial nails) performed over a five year period (January 2015–January 2020). Only one case of deep venous thrombosis (DVT) following femoral lengthening was reported. There is wide variability in practice both in terms of thromboprophylaxis risk assessment, choice of medications and duration of treatment. The vast majority of surgeons (85%) felt that there was insufficient evidence available to guide their practice.ConclusionsIntramedullary lengthening is a surgical treatment growing in popularity. There are limited data available to guide decision-making regarding aspects of treatment such as thromboprophylaxis. This is reflected in the wide variation in practice reported in this study. There are both a need and a desire to gather data that will allow us to come to a consensus and to guide safe practice.Clinical significanceVenous thromboembolism is a potential complication of lower limb lengthening surgery. We report on national incidence and current practices of thromboprophylaxis to allow for informed decision-making and help develop consensus for best practice.How to cite this articleIliadis AD, Timms A, Fugazzotto S, et al. Thromboprophylaxis in Intramedullary Limb Lengthening Surgery. Strategies Trauma Limb Reconstr 2020;15(3):151-156.

FEMORAL LENGTHENING USING MODIFIED LOW PROFILE ILIZAROV FIXATOR IN ADOLESCENTS: DESCRIPTION OF THE TECHNIQUE AND EARLY EXPERIENCE

We modified the original Ilizarov frame described for femoral lengthening and used two full rings fixed by 3 tensioned wires for each with an osteotomy in the distal metaphyseal area. Four femoral lengthenings were performed and followed up for at least 30 months. Average age of our patients was 15 years and length gain was 74±18mm with one patient had concomitant correction of valgus deformity. The planned lengthening was achieved in all patients with healing index 19±2 days/cm. Advantages for this low profile frame are mainly less bulky external fixator and fewer transosseous elements and therefore pin site problems.

Results of Femoral Elongation Treatment Using Electromagnetic Intramedullary Nail. Preliminary Report.

Surgical correction of lower limb discrepancy in children poses a significant clinical problem. The aim of this paper is to present our experience with the PRECICE electromagnetic intramedullary nail. The study group consisted of 5 patients (2 girls; 3 boys) aged 11.5 to 18 years (mean age 16.3) treated for lower limb discrepancy by femoral lengthening using the PRECICE nail intramedullary system. Average discrepancy was 63 mm (range: 45-74.5 mm). Femoral lengthening was successful in all patients. The femur was lengthened by a mean of 49 mm (range: 40-58 mm). A knee flexion contracture of about 10° occurred in one patient. 1. Femoral lengthening in children poses a therapeutic challenge. 2. The PRECICE intrame-dullary nail system helps reduce complications and increases patient comfort.

Extramedullary Motorized Lengthening of the Femur in Young Children.

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. 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. 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. 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 IV-retrospective case series.

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

IntroductionThe 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.MethodsThe 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.ResultsA 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.DiscussionRegional 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.

Femoral lengthening in children

Background: We evaluated the outcomes following femoral lengthening by distraction osteogenesis in children. Additionally, we determined the incidence and nature of complications, the management thereof and factors associated with the development of complications. Method: A retrospective review was performed of all patients who underwent femoral lengthening as an isolated procedure at our institution. Data regarding presenting details and clinical course were collected and X rays analysed. The healing index (HI) and the percentage lengthened were calculated. Complications were defined as deep sepsis, joint contracture, fracture and neurological injury. Results: Fifteen patients underwent 16 femoral lengthenings from 2008–2018. Nine patients had congenital short femur or proximal focal femoral deficiency, three patients had sequelae of meningococcaemia and four had various other pathologies. The median age at time of surgery was 9 years (6–13). Median follow-up was 1.6 years (0.5–6.6). The median HI was 32 days/cm (20–60). Leg lengths were equalised to ≤2.5 cm in 11 patients; length achieved was as planned in all but three patients. Eight patients sustained fractures on average six days (2–57) after frame removal, five through the regenerate. Four required surgery. Thirteen patients developed joint contractures of which six required additional procedures to address this. Two deep infections required surgery. Two patients developed neurological symptoms of which one recovered fully. Higher percentage length gained (>20%) was associated with increased fracture and joint contracture rate. Diaphyseal osteotomy, as opposed to metaphyseal, was associated with increased risk of fracture (71% vs 25%). A diagnosis of congenital short femur was associated with increased fracture rate. Spanning the knee did not prevent joint stiffness in 4/5 patients but did prevent subluxation. Conclusion: Femoral lengthening using external fixation can be successful in achieving leg length equality, but complications are common and often require additional surgery. Limiting lengthening to less than 20% of the original bone length and performing the osteotomy through the metaphysis decreases the risk of fracture and joint contracture. Level of evidence: Level 4

Regenerate Deformity with the Precice Tibial Nail.

Limb lengthening by distraction osteogenesis is an accepted orthopaedic surgical technique. The Precice intramedullary lengthening system is the most recent innovation in limb lengthening. Early results have been favourable in femoral lengthening but there is little reported on the outcome in tibial lengthening. The aim of this study is to present our early results of Precice tibial lengthening, and the stepwise evolution of our surgical technique.Materials and methodsA case series of 17 consecutive tibial lengthenings were prospectively analysed. Healing index, length achieved, range of motion, and complications were recorded. The initial cases followed the recommended surgical technique. Progressive regenerate deformity during lengthening required changes to the surgical method.ResultsNo cases were lost to follow-up. All the nails lengthened at the desired rate. There were no complications of infection or poor regenerate formation. Progressive valgus and procurvatum was prevented in later cases by the positioning of Poller blocking screws at the time of nail insertion.ConclusionThe tibial Precice nail is successful in obtaining length and good regenerate formation. The recommended technique was insufficient to control the deforming forces from the lower limb muscle compartments during lengthening. We therefore recommend the addition of multiple blocking screws in an amended technique.How to cite this articleWright SE, Goodier WD, Calder P. Regenerate Deformity with the Precice Tibial Nail. Strategies Trauma Limb Reconstr 2020;15(2):98–105.

Limb lengthening in down syndrome

Introduction: The average life expectancy for Down syndrome patients has markedly improved. Musculoskeletal disorders occur in 20%–27% of patients with Down syndrome, with hip or knee instability among the most common presentations. Leg length discrepancy has rarely been reported in Down syndrome but can occur as the result of previous lower extremity surgery. This case report presents our experience with the first documented use of an intramedullary lengthening nail to correct a 4.5 cm iatrogenic leg length discrepancy in a skeletally mature Down syndrome patient. Materials and Methods: A single patient surgically treated for leg length discrepancy was followed over a 1-year period and retrospectively reviewed. Results: An 17-year-old male with Down syndrome presented with a 4.5 cm leg length discrepancy secondary to a previously attempted hip fusion. He had been treated with a shoe lift but had difficulty walking with the lift and resorted to toe walking whenever the lift was not being used. His mother, who was his full-time caregiver, was interested in surgical options for permanently correcting his discrepancy. After long discussions over multiple visits covering the risks and benefits of the various choices, the decision to proceed with lengthening of the short limb using a retrograde femoral intramedullary lengthening nail was made. Distraction osteogenesis of 4.5 cm with full consolidation was achieved in this patient without complications. He was able to return to full independent ambulation without a lift by 4 months. Conclusion: Limb lengthening requires a detailed postoperative protocol that may appear to be difficult for a Down syndrome patient with cognitive developmental delay to manage. However, this report documents that if the patient has a reliable caregiver and close postoperative monitoring is maintained, a successful outcome is possible. This represents the first published case of limb lengthening in a Down syndrome patient.

Are There Gender-Specific Errors in Restoration of Hip Biomechanics That Affect Outcome Following Total Hip Arthroplasty?

BackgroundThere are morphologic differences between males and females, which are currently underappreciated during total hip arthroplasty. We sought to assess whether these differences affected surgical process and subsequent outcome. MethodsA total of 123 patients (75 females, 48 males) had preoperative and 1-year Oxford Hip Score (OHS) and pain scores recorded. Acetabular height and offset, femoral height and offset, and acetabular floor depth were measured on preoperative and postoperative X-rays and then compared to their normal opposite hip. Discrepancies between the replaced and normal hip X-ray measurements were then correlated with changes (the delta gain) in preoperative and 1-year postoperative OHS and pain scores. ResultsPostoperatively, females had significantly greater femoral height discrepancy (P = .023) which meant they were lengthened. This led to a reduced delta gain in OHS and pain score at 1 year. Males lost more acetabular offset than females (P = .002), leading to a medialized acetabular center and subsequently reduced delta gain in pain score at 1 year (P = .017). ConclusionFemales have a smaller femur leading to a bias toward a conservative (higher) neck cut compared with males and potential for femoral lengthening. Males have a greater acetabular floor depth compared with females and thus reaming to the true floor results in greater loss of acetabular offset. In this series, both scenarios led to reduced improvement in OHS and/or pain scores at 1 year.

Bifocal treatment for peri-articular femoral nonunions: A retrospective case series review.

Aim:This is a retrospective review of complex periarticular femoral nonunions where bone loss from comminution at original fracture, subsequent infection or lysis was identified and treated by radical excision, internal fixation, and concurrent femoral lengthening from a different level.Material and Method:Sixteen patients with a mean age of 41 years were treated. There were 6 infected nonunions. Ten nonunions were located in the distal femur and the remaining proximal. Case notes and radiograph review were used to determine fracture union, lengthening achieved, and complications. Patient outcome was assessed using the SF-12, Tegner–Lysholm Knee Score, and Oxford Hip Score.Results:Fracture union was achieved in all patients. The mean lengthening performed was 51 mm (range 30–80) with a fixator time averaging 39 weeks (range 17–80). The bone healing index was 1.9 months/cm. All but 2 patients were restored to within 5 mm of opposite leg length; 1 patient subsequently underwent contralateral limb shortening. The SF-12 had a mean Physical Health Composite Score of 40.0 (22.4–52.9) and a mean Mental Health Composite Score of 49 (30.7–62.0). The Oxford Hip Score was scored at a mean of 39 (21–47) and the Tegner–Lysholm score had a mean of 71 (36–94). There were 3 cases of fracture/deformity from the lengthened bone column (regenerate) and 2 patients required a quadricepsplasty for knee stiffness that was present prior to the treatment for the nonunion.Conclusion:Bifocal treatment of complex periarticular femoral nonunions offers a single solution for dealing with bone loss, nonunion, and instability. The method is safe and reliable but has, as with all methods involving distraction osteogenesis, a significant complication rate. Despite this caution, the patients’ outcomes were satisfactory.

Lower limb lengthening over an intramedullary nail: a long-term follow-up study of 28 cases

BackgroundLimb lengthening using an external fixator requires a long period of external fixation and may be associated with several complications such as axial deformity, fracture of the regenerated bone, and joint stiffness. With the goal of reducing the time of external fixation as well as some of these complications, we performed femoral or tibial lengthening over an intramedullary nail, according to Paley’s technique, in 28 patients, followed up after a mean period of 8 years.Materials and methodsTwenty-eight patients treated for lower limb discrepancy by limb lengthening over an intramedullary nail were reviewed from 5 to 11 years after healing of regenerated bone. There were 20 femurs and 8 tibiae, with average age at surgery of 14.2 years and average length inequality of 6.1 cm for femurs and 5.3 cm for tibiae.ResultsThe mean lengthening was 5.8 cm for femurs and 4.8 cm for tibiae. The mean period of radiographic consolidation of the regenerated bone was 6 months for femoral lengthening and 4.5 months for tibial lengthening. At follow-up, we observed 8 excellent results, 15 good results, 4 fair results, and 1 poor result, based on Paley’s evaluation criteria. The main complications were one deep infection, one nonunion of the distracted segment, one breakage of the distal fiche of the external fixator, and one breakage of both distal locking screws of the intramedullary nail.DiscussionWe believe that limb lengthening over an intramedullary nail still represents a good method to treat limb length discrepancy because it reduces the time of external fixation, prevents axial deformities and fractures of regenerated bone, and allows early rehabilitation. The new intramedullary lengthening nails, which theoretically are the ideal device for treating limb length inequality, are still very expensive and need longer follow-up for definitive evaluation.Level of evidence4.

Ilizarov external fixation without bone graft for atrophic femoral shaft nonunion

To explore the effectiveness of Ilizarov external fixation without bone graft in the treatment of atrophic femoral shaft nonunion. The clinical data of 12 patients with atrophic femoral shaft nonunion admitted between October 2010 and January 2017 were retrospectively analyzed. There were 8 males and 4 females, aged from 24 to 61 years, with an average age of 41.7 years. The nonunion sites located in the middle and upper femur in 7 cases and in the distal femur or supracondylar in 5 cases. The disease duration ranged from 1 to 9 years, with an average of 3.7 years. Previous operations ranged from 1 to 9 times, with an average of 2.8 times. The original fixator was removed, the fracture end of nonunion was debrided, and Ilizarov external fixator was installed. In patients with the length of bone defect less than 4 cm, direct compression fixation was performed during operation; in patients with limb shortening more than 2.5 cm, proximal femoral osteotomy and bone lengthening components were required to prepare limb lengthening after operation; all patients did not receive bone graft. The wearing time of external fixator, clinical bone healing time of nonunion fracture end, and complications were recorded. The effectiveness was evaluated by Paley's nonunion evaluation criteria. All patients were followed up 24-50 months, with an average of 30 months. Bony union was achieved in all 12 cases with a healing time of 6.0-23.5 months (mean, 11.5 months). The wearing time of external fixator ranged from 7 to 25 months, with an average of 13.5 months. At last follow-up, according to Paley's nonunion evaluation criteria, the results were excellent in 6 cases, good in 4 cases, and fair in 2 cases, with an excellent and good rate of 83.3%. Sagittal angulation deformity of femur more than 7° occurred in 4 cases, with no significant effect on knee extension function, and no special treatment such as osteotomy was performed. Two patients had shorter limbs (>2.5 cm) after operation and were replaced by high shoes; 4 patients with trans-knee fixation lost knee joint mobility of 10-30° after operation; 10 cases of needle tract infection occurred, of which 4 cases with infection and loosening of fixed needle were replaced and re-fixed after needle extraction, the remaining 6 cases of infection without loosening of fixed needle were controlled by local dressing change, needle nursing, and oral cephalosporin anti-inflammatory drugs. No complications such as deep infection and vascular nerve injury occurred. Ilizarov external fixation has a high healing rate for atrophic femoral shaft nonunion, which is relatively minimally invasive and can avoid bone grafting. Its preliminary effectiveness is exact, and it is also effective for patients who have experienced multiple failed operations. It is necessary to pay attention to the nursing and rehabilitation training after external fixation.

Radiomorphological Manifestations of Femoral and Tibial Cortical Bones at Different Stages of Limb Lengthening.

Background:There has been a lot of research done on Ilizarov's limb lengthening; however, very few publications focus on the quantitative assessment of the distractional bone regeneration in tibial and femur lengthening. Data regarding quality of the bone after lengthening are needed to consider the time of frame removal and develop a rehabilitation program.Materials and Methods:Computed tomography (CT) assessment of a parent bone was performed on 136 patients with limb length discrepancy and bone deformity of various etiologies before and after lengthening. Transosseous osteosynthesis technique with the Ilizarov's external fixation was used for limb lengthening and deformity correction in all the cases. A 64-slice scanner was used for CT assessments. Specific Roentgen-negative units of the Ilizarov apparatus and techniques for interpreting CT findings were employed for artifact-free densitometric assessment.Results:Cortical density of the femur and tibia in patients with limb length discrepancy and bone deformity of various etiologies was shown to have differences as compared to the contralateral limb. The lengthening process was accompanied by decreased cortical density of the segment being lengthened, and the decrease in the density was greater in the areas adjacent to the distractional bone regeneration. The cortical structure underwent characteristic changes. Osteonal density of the cortical bone was higher in the norm and at long term followup as compared to the density of external and internal plates.Conclusion:Cortical bone of the femur and tibia in patients with limb length discrepancy and bone deformity of various etiologies showed various preoperative local densities of external, internal, and osteon layers. The cortical bone demonstrated heterogenic structures with resorption areas of various magnitude and density, with minimal values at the boundary with regenerate bone during distraction and fixation with frame on and at short-term followup. Complete organotypical restructuring of the bone was shown to occur at a 1-to-3-year followup depending on the etiology of the disease and amount of lengthening performed.

Canine Femoral Neck Lengthening Combined with DARthroplasty to Manage Severe Canine Juvenile Hip Dysplasia: A Case Report

Objective This study is a case description of femoral neck lengthening and dorsal acetabular rim (DAR) arthroplasty to treat severe hip luxation in a 5-month-old male Cocker Spaniel (14.3 kg) and to compare the clinical outcome with that of contralateral femoral neck excision. Study design Case report. Results Femoral head coverage improved after surgery (preoperative lateralization of the centre of the femoral head with regard to the dorsolateral acetabular rim: 10 mm; postoperative lateralization of the centre of the femoral head: –1.3 mm). The postoperative Barden's test was negative. The dog was bearing weight 2 weeks postoperatively. Radiographic signs of bone healing were present at the 6-week follow-up examination. No complications were detected. Conclusions Femoral neck lengthening and DAR augmentation were performed in a growing dog affected by severe hip luxation and DAR insufficiency.

Mesenchymal stem cells as adjuvant therapy for limb lengthening in achondroplasia.

Staged leg lengthening allows achondroplastic dwarfs to reach nearly normal height, but it takes long periods of external fixation and it can be burdened by delayed unions. Between 2009 and 2013, eight achondroplastic dwarfs showed delayed unions in the callus formation during femoral lengthening stages in our institute. We performed in-situ injections of bone marrow-derived stem cell concentrates. Patients underwent monthly clinical and radiographic assessment for determination of the healing rate. All eight patients showed an improvement in the regenerated bone, with an average healing index of 23.1 days/cm (range: 18.7-23.8 days/cm). The complete recovery of the delayed consolidation took on an average of 5.2 months (range: 2-10 months). The use of cellular therapy in these patients could represent an innovative application.

Femur lengthening with a telescopic ISKD nail – long-term clinical and radiological results

Femur lengthening with a telescopic ISKD nail – long-term clinical and radiological results

Effectiveness of minimally invasive osteotomy Ilizarov technique combined with intramedullary nail for femoral lengthening

To explore the effectiveness of minimally invasive osteotomy Ilizarov technique combined with intramedullary nail for femoral lengthening. Seventy-one patients with femoral shortening deformity who met the selection criteria between January 2013 and June 2016 were randomly divided into trial group (36 cases were treated with minimally invasive osteotomy Ilizarov technique combined with intramedullary nail for femoral lengthening) and control group (35 cases were treated with simple Ilizarov technique for femoral lengthening). There was no significant difference in age, gender, causes of femoral shortening, length of femoral shortening, rate of femoral deformity between the two groups ( P>0.05). The operation duration, intraoperative blood loss, lengthening rate, external fixation duration, frequency of pin tract infection, osteotomy healing time, and range of motion (ROM) of knee at 1 year after operation were recorded and compared between the two groups. The patients of two groups were followed up 12-60 months (mean, 31 months). Pin tract infection occured in 8 cases (10 pins), including 1 case (1 pin) in the trial group and 7 cases (9 pins) in the control group. There was significant difference in the incidence of pin tract infection between the two groups ( χ2=5.265, P=0.022). All patients were cured by replacing the fixation pins, changing dressing actively, application of antibiotics, and adequate postoperative care. The operation duration, intraoperative blood loss, external fixation duration, osteotomy healing time, and ROM of knee at 1 year after operation of the trial group were superior to those of the control group, showing significant differences ( P<0.05). There was no significant difference in the lengthening rate between the two groups ( t=-1.581, P=0.153). The minimally invasive osteotomy Ilizarov technique combined with intramedullary nail in femoral lengthening increases the operation time, but the external fixation duration and incidence of pin tract infection are significantly reduced and the function of knee is significantly improved.