Introduction. Sheffield Children's Hospital specialises in limb lengthening for children. Soft tissue contracture and loss of range of motion at the knee and ankle are common complications. This review aims to look at therapeutic techniques used by the therapy team to manage these issues. Materials & Methods. A retrospective case review of therapy notes was performed of femoral and tibial lengthening's over the last 3 years. Included were children having long bone lengthening with an iIntramedullary nail, circular frame or mono-lateral rail. Patients excluded were any external fixators crossing the knee/ankle joints. Results. 20 tibial and 25 femoral lengthening's met the inclusion criteria. Pathologies included, complex fractures, limb deficiency, post septic necrosis and other congenital conditions leading to growth disturbance. All patients had issues with loss of motion at some point during the lengthening process. The knee and foot/ankle were equally affected. Numerous risk factors were identified across the cohort. Treatment provided included splinting, serial casting, bolt on shoes, exercise therapy, electrical muscle stimulation and passive stretching. Conclusions. Loss of motion in lower limb joints was common. Patients at higher risk were those with abnormal anatomy, larger target lengthening's, poor compliance or lack of access to local services. Therapy played a significant role in managing joint motion during treatment. However, limitations were noted. No one treatment option gave preferential outcomes, selection of treatment needed to be patient specific. Future research should look at guidelines to aid timely input and avoid secondary complications

Introduction. At Sheffield Children's Hospital, treatment of leg length discrepancy is a common procedure. Historically, this has been done with external fixators. With the development in intramedullary technology, internal nails have become the preferred modality for long bone lengthening in the adolescent population. However, it is important to review whether this technology practically reduces the known challenges seen and if it brings any new issues. Therefore, the aim of this review is to retrospectively evaluate the therapeutic challenges of 16 fit-bone intramedullary femoral lengthening's at Sheffield Children's Hospital between 2021–2022. Materials & Methods. The international classification of function (ICF) framework was used to differentiate outcomes. The patient's therapy notes were retrospectively reviewed for themes around structural, activity and participation limitation. The findings were grouped for analysis and the main themes presented. Results. There were 8 males, mean age 17.4 years (range 17–18) and 8 females, mean age 15.9 years (range 14–18). 5 right and 11 left femurs were lengthened. Underlying pathology varied amongst the 16 patients. All patients went into a hinged knee brace post operatively. Structural limitations included: pain, fixed flexion deformity of the knee, loss of knee flexion, quadriceps muscle lag, muscle spasms and gluteal weakness. The primary activity limitation was reduced weight bearing with altered gait pattern. Participation limitations included reduced school attendance and involvement in activities with peers. Access to Physiotherapy from local services varied dramatically. Five of the cohort have completed treatment. Conclusions. Anecdotally, intramedullary femoral lengthening nails have perceived benefits for families compared to external fixators in the adolescent population. However, there remain musculoskeletal and psychosocial outcomes requiring therapeutic management throughout the lengthening process and beyond. Therefore, quantifying these outcomes is essential for measuring the impact on each patient for comparison. To interpret these themes, we need to evaluate the outcomes objectively, this was not done consistently in this review. Future research should look at outcome measures that are sensitive to all aspects of the ICF. With an aim of improving the therapeutic treatment provided and the overall outcome for the children treated

Introduction: In the management of patients with bone neoplasm, we are confronted with various status which is difficult to treat. External fixation is useful for such status, and result in succes. The purpose of this study is to report that patients of bone neoplasms were treated with external fixation. Materials and methods: Fifteen patients with bone neoplasm who had treated by external fixation are an objective of this study, between 1989 and 2000. Clinical and pathological diagnosis is osteosarcoma in 7, giant cell tumor in 4, Ewing’s sarcoma in 1, chondrosarcoma in1, osteochondroma in 1, enchondroma in 1. Patients were divided into 4 groups depends on difference of indication of external fixation. Result. Group 1. Immobilization of pathological fracture. Two patients with osteosarcoma of femur and one patient with GCT of humerus were treated by external fixation for their pathological fracture. Group 2. Bone lengthening or correction for bone defect or deformity. We performed external fixation with Ilizarov fixator for bone lengthening following bone defect after tumor excision in 4 patients. Mean length of bone defect was 83.5 (22–150) mm. Two in 4 cases were stopped bone lengthening owing to local recurrence and progression of disease. And in 2 patients, we performed correction with external fixation for bone deformity arised by enchondroma of humerus and osteochondroma of ulna. Group 3. Stabilization for vascularized bone graft. We performed vascularized fibular graft after wide resection and stabilized with external fixator in 2 patients with humeral sarcoma. Group 4. Salvage of infected prosthesis. There were 4 patients with infected prosthesis. Three of them were treated by bone lengthening technique after removal of prosthesis. Mean length of bone defect was 264 (220–330) mm and mean term of fitting external fixator was 583.7 (442–726) days. Discussion: Advantages of treatment with external fixation for bone defect, bone deformity and pathological fracture arise from bone neoplasm are mentioned as follows. It could immobilize pathological fracture that is difficult for plaster cast immobilization. It could compensate for bone defect following tumor resection. It is useful method for salvage of the infected prosthesis. Disadvantages of using of external fixation are mentioned as follows. In case of bone lengthening, it is need to perform a complete tumor control. Treatment term is longer. It is need pin site management. Treatment with external fixation is one of the useful method for pathological fracture, bone deformity, shortening, bone defect and infected prosthesis arise from bone neoplasm

Purpose of the study: There is a link between complications and duration of instrumentation. Since 2001, we have associated circular external fixation (EF) and stable elastic centromedullary nailing (SECMN) to shorten the duration of the external fixation in bone lengthening in children. This study was designed to assess the results of the EF+SECMN for this indication. Material and methods: From 2001 to 2009, progressive bone lengthening was performed in 250 children aged 3 to 16 years. There were 295 progressive lengthening procedures involving 339 segments. Indications were congenital (n=163) and acquired (n=87) length discrepancy. In group I (195 lengthenings, 222 segments), the Ilizarov EF was used alone. In group II, the Ilizarov (n=92, 108 segments) or the TSF (n=8, 9 segments) EF was associated with SECMN. After insertion of the EF, the centromedullary nails were introduced after the osteotomies. The healing date was the date the EF was removed; the nails were left in place to protect the bone. The healing index was calculated from duration of the EF (in days) divided by lengthening (in cm). Results: Use of SECMN shortens the duration of EF irrespective of the aetiology, the segment, the lengthening method (mono- or polysegmental, mono- or poly-focal), with a statistically significant difference between the two groups (gain of 6 to 12 d/cm). In group I, deformities or fractures of the regenerated bone after removal of the EF occurred in 21 cases (10.77%), deep infections in 4 (2.05%), osetomyelitis in 2 (1.03%). In group II, the only complications were late healing (1%) and 10° angulation at the lengthening site (1%). The centromedullary nails migrated in eight patients, with no impact on the lengthening results. Discussion: With SECMN, the lengthening procedure is achieved with an elastic but resistant system. It is hypothesised that this system stimulates osteogenesis since the healing index is improved. SECMN does not prevent progressive correction of shaft or diaphyseal deviations. By shortening the duration of external fixation, this method had a great impact on reducing serious complications such as fractures and deep infections. Conclusion: SECMN can considerably reduce the duration of external fixation during bone lengthening procedures in children and reduce (or eliminate) most of the serious complications

Purpose: The purpose of this study was to evaluate centromedullary pinning for bone lengthening. We studied an animal model to discover the details of bone regeneration and assess the advantages of the technique. We present our early clinical results. Material and methods: Progressive lengthenings of the tibia by centromedullary pinning were performed in eleven dogs. Distraction began on day 5 and lasted 28 days. Arteriograms were obtained after sacrifice.We also analysed 17 cases of limb lengthening in patients: one arm, two forearms, nine femurs, five tibias. Mean patient age was 14 years. Mean gain in bone length was 6.2 cm. Results: The experimental work demonstrated that intensive bone regeneration requires faster distraction. Early bone union was observed in four dogs. Bone healing was complete at about 15 days in all dogs. The centromedullary pins were left in place in three dogs after removing the external fixator. There was no secondary deformation. The arteriogram showed that the nourishing artery was not ruptured. In our patients, delay to healing was shorter. The radiograms demonstrated intensive bone regeneration. Endosteal regeneration was significant and was never inhibited. Significant periosteal reaction was observed. The planned gain in length was achieved in all patients. We did not have any complications. Discussion: Bone lengthening methods using a centromedullary nail provide absolute stability while avoiding external fixation but at the cost of complete destruction of the centromedullary vascular supply. Our animal experiments and clinical experience prove that elastic centromedullary pins do not inhibit endosteal regeneration but, on the contrary, partial destruction of the marrow with intact vascularisation stimulates bone regeneration. For bone lengthenings, centromedullary pinning is the only method of internal fixation allowing optimal conditions for bone regneration. Conclusion: The progressive distraction of the elastic centromedullary pin during the lengthening period stimulates the regenerative processes. The biological effect of the vascular “displacement” from the centre to the periphery of the bone fragments leads to significant periosteal reaction. Elastic centromedullary pinning adds stability to the bone fragments. Associating the two methods allows removal of the external fixator leaving the centromedullary pins in place. By strengthening the regenerated bone, the pins provide a certain degree of additional stability

Introduction. Since 2001 we use the flexible intramedullary nailing (FIN) in bone lengthening in children. This study estimates results of EF+FIN association considering the duration of external fixation and complications. Materials and Methods. Since 2001 we performed 294 bone lengthenings (338 segments of UL and LL) in 250 children 3 to 16 years old (11.01±0.23 in average). The length discrepancy was congenital in 163 cases, the sequelae of trauma or osteomyelitis were observed in 87 patients. In group I (195 cases) the Ilizarov fixator alone was applied, in group II the Ilizarov fixator (91 cases) or TSF® (8cases) were combined with FIN. The healing index was compared between the groups of the same etiology with similar type of distraction osteosynthesis. The date of consolidation corresponded to the day of removal of the external fixator, while intramedullary nails remained in place thus protecting the bone. Healing index was calculated by relating the duration of wearing of the external fixator (in days) and the amount of lengthening (in cm). Results. Reduction of the healing index is noted in each compared category. Thus, in congenital shortening in monofocal distraction osteosynthesis of the femur the healing index decreased from 29.8 (group I) to 20.4 days per cm, in bifocal tibial lengthening from 22.7 (group I) to 16.3d/cm (group II), in humeral lengthening – from 30.2 to 21.3 d/cm. In fact, it appears that the association of the external fixator of the Ilizarov type or TSF® with FIN allows to reduce the healing index significantly: in 12 of 16 compared categories the reduction of the index was from 20% to 40% or from 4.0 to 19.1 days per cm. In group I four cases of deep infection of soft tissues, 2 osteomyelitis, 21 fractures or deformities after frame removal were manifested. In group II – onlyone case of deformation after frame removal, absence of severe infectious complications, 8 cases of migration of the intramedullary wires. Discussion. FIN creates an elastic and resistant system during the lengthening. We even suggest that it stimulates the formation considering an apparent decrease of the healing index. On the other hand, the elasticity of nails prevents secondary fractures or deformations after frame removal. Conclusion. Combination of the circular EF and FIN in limb lengthening in children significantly decreases the duration of external fixation and the amount of severe infections and fractures

Management of bone defects is a common surgical challenge encountered following any high energy trauma. Femur fractures with bone loss account for 22% of all the fractures with bone loss/defect, and 5% to 10% of distal femur fractures are open injuries. It was estimated in 2008, that, more than 4.5 million open fractures occur annually in India. In this retrospective study, patients who received bone allograft from our tissue bank between May 2012 and September 2015 were analysed. Of the 553 allografts issued, at that point in time, 26 were used in patients who underwent reconstruction for distal Femur fractures primarily. Fractures with defect or bone loss from 12 cc (1cm) to 144 cc (12cm) were treated with either Internal or External fixation and bone allograft. Morcellised cancellous, or a cortical strut, were used to fill or reconstruct the defect or void. The radiological outcome in terms of fracture union was assessed and Knee society score was used to assess the functional outcome. Complications such as non- union, infection, stiffness and need of revision or additional procedures were also assessed. Osseous consolidation was achieved in all the 26 patients with a Median time of 24 weeks (16 to 60). The Median Functional Knee Society Score was 80, indicating satisfactory functional outcome. Infection was noted in one patient, but it was not attributed to the allograft. Additional minor procedures like bone marrow infiltration, corticotomy for bone lengthening were required in 10 patients. Our studycomprises the largest group of patients treated primarily with Allograft to reconstruct or fill the void of bone loss encountered with distal Femur fracture. Reconstruction of massive bone defects, in patients of distal Femur fractures, with bone allograft, shows encouraging results. The surgeon can achieve the goal of restoring form and function of these difficult injuries in a single stage and the technique will provide the freedom to reconstruct the bony defect up to 150 cc (12 cm length) and recreate the anatomy to near normal. This allows for early mobilisation of patients and restoration of their daily routine at the earliest

Aims

Distraction osteogenesis (DO) is a useful orthopaedic procedure employed to lengthen and reshape bones by stimulating bone formation through controlled slow stretching force. Despite its promising applications, difficulties are still encountered. Our previous study demonstrated that pulsed electromagnetic field (PEMF) treatment significantly enhances bone mineralization and neovascularization, suggesting its potential application. The current study compared a new, high slew rate (HSR) PEMF signal, with different treatment durations, with the standard Food and Drug Administration (FDA)-approved signal, to determine if HSR PEMF is a better alternative for bone formation augmentation.

Purpose. The purpose of this study was to assess the accuracy of three-dimensional camera technology when monitoring deformity correction by an Ilizarov frame and to compare it to manual measurements. Methods and Results. A model consisting of an Ilizarov frame built around an artificial tibia and fibula was used with retro-reflective markers placed on the frame and bones to allow for the positions of each to be detected by the camera system. Measurements made by the camera system were compared to measurements taken manually. In the assessment of frame lengthening, the camera system average error was 2% (SD 2%) compared to 7% (SD 6%) for manual measurement. In the assessment of bone lengthening, the camera system average error was 4% (SD 4%) compared to 34% (SD 8%) for manual measurement. The technology also demonstrated good accuracy in the measurement of angular deformity changes. Conclusion. The results of this study demonstrate that the measurement of deformity correction with three-dimensional infra-red camera technology is superior to manual measurements in a model of deformity correction. This method could replace or greatly reduce x-ray exposure in monitoring deformity correction post-operatively

We report our experience of a humanitarian mission to treat the earthquake victims of October 2005 in Pakistan. The team with their equipment, in two periods of four and ten days respectively, treated 26 fractures in 25 patients with the Ilizarov frame and principles. There were 21 III B open fractures and three Tscherne III closed fractures. Seventeen fractures were infected with discharging pus and non-viable bone. Injuries were treated aggressively using different Ilizarov techniques of reconstruction surgery. All but two open fractures required a plastic surgical procedure for wound cover. Three months post-operatively eight out of thirteen fractures which had been treated in the first four days of the visit were healed and corticotomy for bone lengthening, performed during the second 10 days period visit. All wounds have remained clean with no evidence of superficial or deep infection. Limb lengthening procedures are planned for the rest of the patients

Aims and methods. We present a review of our use of the Ilizarov apparatus in a non-acute NGO hospital in Cambodia specialising in limb reconstruction. Frames are applied without on table image intensification. A retrospective case-note analysis of Ilizarov apparatus use for all indications was conducted. 53 frames were applied between November 2005 and October 2011. Indications for application were chronic open fracture, osteomyelitis, fracture malunion, infective and non-infective non-union, bone lengthening, primary bone tumour resection, ankle fusion, congenital deformity or pseudarthrosis, chronic hip dislocation, or a combination of the above. Results. Median delay in presentation was 104 weeks for all indications (range 4–864). Median treatment length was 21 weeks (3–76). The most frequent complication was pin-site infection. This occurred in 18 patients (34%). Return to theatre occurred in 21 patients (40%). Indications were frame adjustment, pin addition or removal, addition of bone graft or re-osteotomy. Failure of union occurred in three patients. These rates are comparable with those published in both Asian and Western literature. Conclusions. Our data demonstrate the versatility of the Ilizarov apparatus and its importance in limb reconstruction in a developing world setting. Our centre relies on it as a cost-effective tool for traditional and novel indications. In our centre the apparatus is applied without x-ray control and is maintained without a dedicated outreach pin-site care programme. Despite this our complication rates are comparable with western literature. We therefore recommend it as a safe and cost-effective tool for use in other developing world settings

Aims

This study aims to enhance understanding of clinical and radiological consequences and involved mechanisms that led to corrosion of the Precice Stryde (Stryde) intramedullary lengthening nail in the post market surveillance era of the device. Between 2018 and 2021 more than 2,000 Stryde nails have been implanted worldwide. However, the outcome of treatment with the Stryde system is insufficiently reported.

Purposes of the study. To assess safety, lengths gained, frame time and perform cost analysis of the technique of submuscular plating to the femur and tibia following distraction osteogenesis. Introduction. Since 2005 we have performed submuscular plating to the femur and tibia after distraction osteogenesis in order to shorten time in external fixator. Aim. To assess safety, lengths gained, frame time and perform cost analysis. Methods. Retrospective analysis using notes and digital radiographs, with cost codes for 2011 prices. Patients. 23 patients (14 male), mean age 11 (range 4 to 17). 14 diagnosed as congenital longitudinal deficiency. Total 37 bones lengthened (14 femur and tibia, 7 tibia only, 2 femur only). Ilizarov fixator most commonly used for tibia, LRS fixator for femur. Results. Mean length gained 68 mm per patient, 43 mm per bone. Mean frame time 121 days. Fixator index 0.59 months/cm per patient, 0.90 months/cm per bone. Mean cost £20100 per patient, £12500 per bone, £2800 per cm length. Cost attributable to plating £5100 per patient, £3300 per bone. Complications: 5/24 had pinsite infections, 2/24 required tendon releases, 1/24 had deformity, 1/24 sustained a fracture proximal to femoral plate. No deep infections. Conclusions. Plating after lengthening is a safe procedure with no deep infections. The frame time is low (0.6 months/cm per patient) but increases overall costs by an extra £5000

The frequent choice of treatment for tibial shaft fractures is intramedullary nailing. However there are cases where this treatment is problematic and alternative treatments are chosen with satisfied results. Twenty-nine patients with complex, unstable tibial shaft fractures (13 males and 16 females) aged 18 to 76 years (mean age 49 years) were treated using Ilizarov external fixation, the last decade in our Department by the same surgeon. The indications were open Gustillo III fractures, comminuted fractures of the proximal or distal third tibia near metaphysis, concomitant plateau or pillon fractures and fractures after total knee arthroplasty (TKA). All frames were applied the first day of injury. Patients without concomitant intraarticular fracture or bone deficit allowed to full weight bearing within2 weeks after surgery. Union and good to excellent alignment with full range of motion in the knee and ankle joints was obtained in all patients. Three patients needed bone lengthening using the initial applied frame after corticotomy in second operation. There were 7 delayed unions in fractures without bone deficit, 10 superficial pin tract infection treated with antibiotics and local care and 1 deep infection which needed surgical intervention. Ilizarov external fixation gives the solution in difficult and problematic tibial shaft fractures and allows early weight bearing

Aims. Since 2005 we have performed submuscular plating to the femur and tibia after distraction osteogenesis in selected cases in order to shorten the time in external fixator. The aim was to assess safety, lengths gained, frame time and perform cost analysis. Methods. Retrospective analysis using notes and digital radiographs, with cost codes for 2011 prices. 23 patients (14 male), mean age 11 (range 4 to 17) were analysed. 14 were diagnosed as congenital longitudinal deficiency. Total 37 bones lengthened (14 femur and tibia, 7 tibia only, 2 femur only). Ilizarov fixator most commonly used for tibia, LRS fixator for femur. Results. Mean length gained 68mm per patient, 43mm per bone. Mean frame time 121 days, with mean 75 days of lengthening, and mean 46 days between the cessation of lengthening and the plating procedure. Fixator index 0.59 months/cm per patient, 0.90 months/cm per bone. Mean cost £20100 per patient, £12500 per bone, £2800 per cm length. Cost attributable to plating £5100 per patient, £3300 per bone. Complications: 5/24 had pinsite infections, 2/24 required tendon releases, 1/24 had deformity, 1/24 sustained a fracture proximal to femoral plate. No deep infections. In terms of patient satisfaction, families of patients who had also undergone a prior lengthening with frame only, 80% preferred plate after lengthening. Conclusions. Plating after lengthening is a safe procedure with no deep infections. The frame time is low (0.6 months/cm per patient) but increases overall costs by an extra £5000 per patient. There is room to improve the fixator index further if the time between cessation of lengthening and the plating procedure (currently 46 days) is shortened

Introduction: the choice of treatment for tibial shaft fractures in adults is intramedullary nailing. However there are cases where this treatment is problematic and alternative treatments are chosen. Patients and Methods: 29 patients with unstable tibial shaft fractures (13 males and 16 females; aged 18 to 76 years) were treated using Ilizarov technique, last decade, by the authors. The indications were open fractures type III Gustillo, comminuted fractures of the proximal or distal third near metaphysis, concomitant plateau or pillon fractures and fractures after TNR. All frames were applied the first day of injury. Patients without concomitant intraarticular fracture or bone deficit allowed to full weight bearing within two weeks after surgery. Results: union and good to excellent alignment with full range of motion in the knee and ankle joints was obtained in all patients. Three patients needed bone lengthening using the initial applied frame after corticotomy in second operation. There were 7 delayed unions in fractures without bone deficit. As complications there were superficial pin tract infection in 10 patients treated with antibiotics and local care and one deep infection which needed surgical intervention. Conclusions: Ilizarov technique gives the solution in difficult and problematic tibial shaft fractures and allows early weight bearing

We present an original method for the treatment of neglected Monteggia fractures using the Ilizarov technique. This method allows reduction without accessing the radial head by progressive ulnar lengthening after proximal subperiosteal osteotomy of the ulnar bone. We used this method in a six and a half year old girl and achieved excellent radiographical and functional results with normal joint amplitudes. In our opinion, the quality of the outcome is related to the progressiveness of the bone lengthening enabled by this technique which allows restoration of the ulnar length, preservation of the axes of both forearm bones, and controlled reduction of the radial head

To study the use of TSF system in treating trauma and bone deformities in children. To determine the difficulties of this process and the risk factors that lead to complications. From January 2004, in 61 children (37 male and 24 female), 67 extremities, with a mean age 8.9 years children a TSF external fixator was applied for the treatment of trauma or bone deformities. 21 children were operated for angular deformity, 19 for bone lengthening, 10 for rotational deformity, 6 for combined angular deformity and lengthening and 11 for pseudoarthrosis. Intra and postoperative difficulties were classified using the Palay method in problems, obstacles and complications. The rate of difficulties was 22.2 %. Problems were presented in 5.9% (4/67) consisting of 2 non-axial deformities, 1 pin fracture and 1 subluxation of the knee. Obstacles were presented in 10.4% (9/67) including 3 cases with delayed bone healing that needed infusion DBM, 1 peroneal nerve palsy due to hematoma formation treated with decompression of the region, 1 early bone fusion that needed re-operation and 2 cases of percutaneous achilles lengthening. Complications presented in 5.9% of (4/67) the cases including 1 fracture, 1 pseudoarthrosis, 1 peroneal nerve palsy and 1 limitation of range of motion in the knee (0–45 0). The problems, obstacles and complications that presented during treatment influenced the final therapeutic objective. Initial deformity, preoperative planning and surgeon’s experience are associated with reducing the rate of all difficulties

Hig energy fractures of the lower limb are often associated with tibial or femoral bone loss, skin exposition with vascular and nervous injuries (Gustilo et al.). The surgical procedure is a real challenge, consisting in a temporary stabilization of the fracture associated with a plastic and/or vascular reconstruction. Once the skin and vascular injuries are recovered, the orthopaedic surgeon can remove the temporary stabilization performing a circular external fixation with bone lengthening by using the “bifocal” (one site of metaphiseal corticotomy and one site of compression) or “trifocal” (two sites of metaphiseal corticotomy and one site of compression) technique. We use to do a “docking site” treatment when bone fragments are nearly in contact. Our experience indicates that circular external fixation, by using the Orthofix system, is a very useful and safe technique in the management of severe lower limb injuries. Our good clinical results lead us to suggest this surgical technique that allow to obtain a limb reconstruction, avoiding segment amputation

Objective: The purpose of the present study was to assess whether clinicians are actually able to evaluate the mechanical status of lengthening callus from plain radiographs. Materials and Methods: 36 rats were employed in this study. Their left femurs were lengthened by 6 mm as a bone lengthening model. Rats were euthanized at 4 8 12 and 16 weeks after lengthening. Both femora were X-rayed and then bone density parameters (bone mineral content, bone mineral density and bone area) of lengthening callus were measured using pQCT. Three-point bending test was performed to determine the mechanical strength of the both bones. We defined the ratio of the strength of lengthening side to control side as estimated strength recovery rate (%). Then 20 orthopaedic surgeons evaluated only the X-ray photographs and tried to estimate the relative mechanical strength (%) of the affected side compared to the control side. Results: Between the recovery percentage of mechanical strength and bone mineral content, a positive simple correlation (R2=0.11, p< 0.05) was seen. No significant correlation was seen between the recovery percentage of mechanical strength estimated by orthopaedists and the mechanical strength measured by three-point bending test (qualified doctors: R2=0.0793 p=0.291 unqualified doctors: R2=0.0523 p=0.394). Discussion and conclusion: It became obvious that to estimate the strength of lengthening callus from plain radiographs alone is quite difficult as compared with the studies of the simple fracture model that have been reported until now