Introduction. The practice of limb lengthening using intramedullary nails has surged in popularity in recent years. Our study explores the relationship between femur lengthening and overall height gain in adults undergoing cosmetic limb lengthening with telescoping magnetic intramedullary lengthening nails (MILNs). Materials & Methods. Demographic information, pre- and postoperative radiographic data, and secondary outcomes, such as mechanical angles and sagittal alignment, were analyzed for 42 adult femurs MILNs (PRECICE 2, NuVasive, Inc.). Height was assessed with a digital stadiometer. Limb lengthening was defined as the amount of nail distraction seen on a calibrated weight bearing X-ray at consolidation. mLDFA, mMPTA, MAD, AMA, and femoral sagittal bow were evaluated as secondary outcomes. Results. Mean starting height was 163.5 cm (SD 10.4, range 137–179) Post -lengthening mean height increased to 171.1 cm (SD 10.1, range 146.7–185.3). Average height gain was 7.5 cm (SD 1.3 cm, range 5.1–9.5). Average femoral lengthening was 7.3 cm (SD 1.14, range 4.1–10.1). There were no statistically significant difference between height gain and femur lengthening. Secondary outcomes showed reductions in femoral sagittal bow and AMA. Conclusions. We conclude that measuring femur lengthening is a reliable and accurate method of measuring gained height in deformity-free patients undergoing limb lengthening. We further reason that straightening of both femoral and spinal sagittal bow counteracts potential lengthening loss over the anatomical axis, versus mechanical axis lengthening

Introduction. “Bioexpandable” prostheses after resection of malignant bone tumors in children to lengthen the bone using the method of callus distraction may offer new perspectives and better long-term results. Materials and Methods. The bioexpandable prosthesis is equipped with an encapsulated electromotor which enables the device to perform distraction in an osteotomy gap with about 1mm/day. The new bone is improving the ratio from bone to prosthesis and therewith the potential stability of the final stem. The device is indicated, when limb length discrepancy is getting more than 3 cm or at maturity and can be used in a minimal invasive way for femur lengthening. Results. 11 patients were treated with the bioexpandable prosthesis. The mean age of the patients was 13,5 years and the mean amount of lengthening was 74mm. In 2 cases lengthening was performed in 2 steps and in 1 case in 3 steps. All lengthening procedures could be finished without complications. There was no infection and no technical problem. The bone regenerate in one tibia case was poor so that bone grafting from the iliac crest was necessary. Conclusions. The “bioexpandable” prosthesis is a new concept for limb lengthening after tumor resection in children. The latest patented version of the prosthesis under development allows all lengthening manoeuvres and the placement of the final stem via small incisions not only for the femur but also for the tibia

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

Background. Lengthening over nail (LON) and the use of internal lengthening nails have been developed to minimize patients' time in a frame during femur lengthening. This study compares the outcomes of two techniques of femur lengthening, LON and Intramedullary Skeletal Kinetic Distraction (ISKD). Methods. In this retrospective study, 12 consecutive ISKD procedures were performed for femoral lengthening and followed for an average of 76 months. After the ISKD group, 20 consecutive femoral lengthening procedures were performed as an LON technique and followed for an average of 27 months. Results. There was no significant difference in achieving the lengthening goals between the two procedures. The healing index for the LON group averaged 1.4 months/cm, while the ISKD group was 3.2 months/cm (p=0.242). The distraction rates for the ISKD had a fast group (>1mm/day) with an average distraction rate of 1.7 mm/day and a slow group (<1mm/day) with a distraction rate of 0.84 mm/day. The LON group had an average distraction rate of 0.88 mm/day (p<0.001). The incidence of complications that required further unanticipated surgeries for the LON group was 1/20 (5%), while the ISKD group had complications in 6/12 femurs (50%, p=0.004). Conclusions. We concluded that the LON technique is a more predictable and reliable method for femoral lengthening than the ISKD

Many studies describe the use of the Ilizarov ring fixator for lower limb lengthening and for the management of the 3-dimensional lower limb deformities in achondroplasia, and most confirm the efficacy of this technique. However, long term follow up of these achondroplastic patients is lacking. Most studies have focused on magnitude of lengthening, treatment time required and complications, but no study has analyzed the long term postoperative condition of these patients using an objective, functional method such as gait analysis. Nineteen (19) achondroplastic patients, 12 males and 7 females, aged 19–38 years (mean 27.3 y) who have undergone tibia and femur lengthening, using the Ilizarov method, at the age of 9–19 years (mean 12.6 y), were evaluated 5–19 years (mean 10.1 y) after their last surgery, using 3-dimensional gait analysis. Nineteen (19) normal, height-matched subjects were used as controls. The VICON Nexus 8 Camera System was used to accurately measure spatiotemporal characteristics (walking velocity, stride length, step length, cadence) and kinematics (range of motion) of lower limb joints. Statistical comparison of deformity parameters between achondroplastic patients and normal population was done using the student t- test. A level of p<0.05 was considered statistically significant. Walking velocity, step length and stride length were statistically significantly decreased (p<0.05) in achondroplastic patients compared to normal population values. The achondroplastic group presented with excessive anterior pelvic tilt (mean 21.9. o. ± 7.3), excessive pelvic rotation (range 28.7. o. ±7.8), decreased hip extension (mean 1.8. o. ±10.1) and decreased plantar flexion (mean 17.1. o. ±5.1) when compared to normal controls. There was no statistically significant difference in the knee kinematics between the operated achondroplastic patients and normal controls. The achondroplastic patients present decreased values in their spatiotemporal characteristics compared to the normal subjects because, despite the height gain, their lower limbs remain shorter. Their excessive anterior pelvic tilt is attributed to their lordosis. Their excessive forward pelvic rotation is an attempt to increase stride and step length. The decreased hip extension is due to their anterior pelvic tilt. The correction of these patients genu varum restored knee kinematics to normal. In order to address the hip and pelvis deformities a proximal femoral osteotomy should be considered. The Ilizarov method provides functional height gain and substantially corrects the three-dimensional lower limb deformities of achondroplastic patients especially around the knee joint but more planning needs to be implemented when the system is applied to correct the disease specific deformities of the hip and pelvis. Gait analysis is an objective tool that can be used to address these design issues

Aims

Surgical limb sparing for knee-bearing paediatric bone sarcoma is considered to have a clinically significant influence on postoperative function due to complications and leg-length discrepancies. However, researchers have not fully evaluated the long-term postoperative functional outcomes. Therefore, in this study, we aimed to elucidate the risk factors and long-term functional prognosis associated with paediatric limb-sparing surgery.

Explanations for “bearing” noise in ceramic-on-ceramic hips (COC) included stripe-wear formation and loss of lubrication leading to higher friction. However clinical and retrieval studies have clearly documented stripe wear in patients that did not have squeaking. Seldom highlighted has been the risk of metal-on-metal or metal-on-ceramic impingement present in total hip arthroplasty (THA) with metal and ceramic cup designs. The limitation in THA positioning studies has been (i) reliance on 2-dimensional radiographic images and (ii) patients lying supine on the examination table, thus not imaged in squeaking positions. We collected eleven squeaking COC cases for an EOS 3D-imaging functional study. Hip positions were documented in each patient's functional ‘squeaking’ posture using standard and 3-D EOS images for sitting, rising from a chair, hip extension in striding, and single-legged stance. EOS imaging documented for the 1st time that postural dysfunctions with potential impingements were demonstrable for each squeaking case. The 1st major insight in this study came from a female patient who complained of squeaking while walking in flat-soled shoes (Figs. 1a, b). She found that when wearing high-heeled shoes her hip stopped squeaking (Figs. 1c, d). Her lateral EOS view in standing position with heeled shoes revealed that the femoral stem had approximately 3o less hyper-extension compared to flat shoes (Figs. 1b, d, arrows #1,3). The three-dimensional ‘sky-view’ EOS reconstruction of pelvis and femurs (Fig. 2) showed that her femur was also more internally rotated when she wore heels. These subtle shifts in position changed her COC hip from one of squeaking to non-squeaking. A squeaking male patient observed similar postural effects while walking up his boat ramp but not going down the ramp. In both cases, the squeaking was a consequence of cup impinging on a metal femoral neck. Thus the primary cause of squeaking appeared to be hip impingement, i.e. repetitive subluxations that patients generally were not aware of. Another case is representative of situations due to atypical and subtle cup/stem mal-adjustments (Fig. 3); frontal pelvic-tilt, thoracolumbar scoliosis, with 1cm of femur lengthening and a significant increase of offset are observed. Also evident was the femoral-neck retroversion in both standing and sitting. Squeaking occurred when modification of the functional neck orientation occured in one-legged stance (Fig. 3c) or when climbing a stair (Fig. 3d). It was apparent in our EOS studies that patient functionality controlled whether squeaking occurred or not. Thus the new data indicated COC squeaking was a three-fold consequence of component positioning, spine and pelvic adaptions, and variations in patient posture. One limitation here is that our conclusions are based on a small sample of patients and may not be applicable to all. A consequence of such repetitive impingement can be cup rim damage and neck-notching, with release of metal debris. It is well documented that retrieved ceramic bearings are frequently stained black. Thus hip squeaking may likely result from (i) impingement and secondarily (ii) due to ingress of metal particles, and then (iii) producing a failure of lubrication. To view tables/figures, please contact authors directly

Since the time of Charles Darwin, it is known that three principles of regeneration explain the similarity of neo-formed tissues, the dependence of regeneration rhythm on age and the position of the animal in the evolutionary chain. The latter principle is know as the Weisman-Pschibram principle. Regeneration depends on several factors: level of tissue specialisation and differentiation, tissue resistance to hypoxia, and other manifestations of generally recognised biological regulation. According to a fourth principle, the regenerative potential of different parts of the body depend on a cranio-caudal gradient which rhythms their postnatal growth and development. Distinction of this principle is of importance because of its practical applications. Experience with increasing the height of persons with achrondroplasty by lengthening different limb segments reveals that the femur has less regeneration potential despite its long length. Leg lengthening is preferred; saving muscle function, there is a 20% potential for lengthening. Male subjects are generally considered to be short in height when there is a 10% growth retardation of the longitudinal dimension of the body. In female subjects, generative function is considered deficient if the length of the trunk is less than 73 cm. Using these criteria, experience has shown that leg malformations are not observed in subjects with a 10% growth retardation of the limb. The rate of growth retardation has to reach 40% before growth ceases. The relative moment of posterior leg muscle force increases with increasing leg length (F = 0.063 x L – 0.7; r=0.965, n=123). With a 10% growth deficit, the leg lengthening operation limits the amplitude of ankle movement 15% on average. With the same 10% growth deficit, lengthening the femur with the same technique decreases the amplitude of knee movement 22%. It has been noted that a 40% decrease in leg muscle force after leg lengthening does not affect locomotor function. The same decrease in thigh muscles after femur lengthening alters function. Like the first three principles, the fourth has its exceptions. It is important however to distinguish the influence of biological factors from other, for example technical, factors. Thus orthopaedic surgeons prefer the humerus for lengthening the upper limb, but this results from the difficulty in preserving rotation movements when lengthening the forearm. The important advances obtained in recent years in patients with bony defects of the hand and foot are further arguments clearly in favour of the existence of a cranio-caudal gradient in regenerative potential of the limbs

Purpose: External fixators are widely used for limb lengthening procedures. More recently the femoral nail has been introduced combining the advantages of progressive lengthening obtained with external fixation and of the percutaneous approach of internal fixation. This retrospective analysis of 14 patients treated with the progressive femur lengthening nail (ECMP) Albizzia®, was conducted to analyse results in terms of limb length correction, bone healing and complications. Material and methods: The fourteen patients, nine men and five women, mean age 27.3 years had leg length discrepancies = 20 cm. All were treated with the ECMAP nail (Albizzia®)in January or February 2000. There were nine right legs and five left legs. The patients had discrepancy subsequent to trauma (64.3%), hip dysplasia (21.4%) or neurological (7.15%) or infantile (7.15%) conditions. Mean leg length discrepancy was 41.5mm (20–150 mm); 57.1% of the patients wore a raised heal and 14.2% used crutches. The nail was inserted with reaming and locked on both ends. The corticotomy was made with an endomedullary saw in a closed procedure for 78.5% of the patients and with an open procedure for 21.5%. Angular correction was associated in 32.7% of the cases. Outcome was analysed on the basis of operative time, blood loss, rhythm and amount of limb lengthening, delay to healing and complications. Results: Mean follow-up was 25 months. Mean operative time was 2 hr 28 min. The lengthening procedure began 4.1 days after nailing with, on the average, 20 ratchet clicks per day. Mean duration of the lengthening procedure was 32.5 days. Mean lengthening was 32.15 mm, i.e. 0.99 mm/day. Ten patients had a general anaesthesia at least twice to manipulate the nail ratchet. There were five cases with mechanical complications and one case of regressive nerve injury. There were no infections, no cases of joint stiffness and no axis defects. Bone healing was achieved a mean 2.7 days. There was one nonunion. Mean haemoglobin loss was four points, three patients required transfusion. Limb length was equivalent in six patients, with < 5 mm discrepancy in three, 6–10 mm discrepancy in one, 11 mm discrepancy in two and 64 mm discrepancy in one. One lengthening procedure had to be interrupted before term. Discussion: ECMAP is unable to avoid the complications inherent in lengthening procedures but does offer undeniable advantages over external fixation. The risk of infection is very low and skin scars are minimal. Patient comfort is greatly improved (elimination of the cumbersome external fixator). Delay to bone healing is satisfactory and axial rotation defects can easily be corrected. This technique appears to be an excellent means for lengthening the femur in trauma patients

Introduction. Perthes' disease is associated with coxa breva, plana and magna, and a high riding prominent greater trochanter causing abductor shortening and weakness, leg shortening and extra-articular impingement. A trochanteric advancement with an infero-lateralising oblique sliding osteotomy of the proximal femur would lengthen femoral neck, improve abductor length and strength, relieve impingement and improve leg length. We assessed the mid-term outcomes for this procedure. Method. We included patients who underwent the operation by the senior author (JNOH) with more than 2 years follow-up. The osteotomies were performed minimally invasively under image intensifier guidance and fixed with blade plate or locking plates. We assessed functional scores, radiological changes in neck length, Tonnis grading for arthritis and evidence of femoral head avascular necrosis, time interval for conversion to hip arthroplasty and associated complications. Results. Twenty four patients (25 hips) underwent the procedure at mean age of 18.7 years (range:9.3–38.8) with a mean follow-up of 5 years (range:2–13.8). At the last assessment, the mean Oxford Hip Score was 41.6 (range:58–27), Non-Arthritic Hip Score was 53.4 (range:25–77) and UCLA activity score was 4.2 (range:2–6). For changes in neck length, the mean “Head-centre-to-Greater-trochanteric-tip-distance” was 60 mm (range:43–78) compared to 39 mm (range:30–48) pre-operatively and the mean “Head-centre-to-Lesser-trochanteric-tip-distance” was 54 mm (range:47–64) compared to 37 mm (range:31–41) pre-operatively. The mean Tonnis grade was 1.5 (range:1–3) compared to 1.3 (range:1–2) pre-operatively. Two patients underwent arthroplasty conversion at 2 and 13.8 years later. One patient needed head-neck debridement for impingement and 2 patients underwent trochanteric refixation for non-union. There were no cases of avascular necrosis. Discussion. Symptomatic Perthes' hip deformity in adolescents and young adults is difficult to treat with joint preserving surgery. The mid-term clinical, functional and radiological results for double proximal femur osteotomy are encouraging

Introduction. Perthes disease is associated with coxa breva, plana and magna, and a high riding prominent greater trochanter causing abductor shortening and weakness, leg shortening and extra-articular impingement. A trochanteric advancement with an infero-lateralizing sliding osteotomy of the proximal femur would lengthen femoral neck, improve abductor length and strength, relieve impingement and improve leg length. We assessed the mid-term outcomes for this procedure. Method. We included patients who underwent the operation by the senior author (JNOH) with more than 2 years follow-up. The osteotomies were performed under image intensifier guidance and fixed with blade plate or locking plates. We assessed functional scores, radiological changes in neck length, Tonnis grading for arthritis and evidence of progression in femoral head avascular necrosis, time interval for conversion to hip arthroplasty and associated complications. Results. Twenty four patients (25 hips) underwent the procedure at mean age of 18.7 years (range:9.3–38.8) with a mean follow-up of 5 years (range:2–13.8). At the last assessment, the mean Oxford Hip Score was 41.6 (range:58–27), Non-Arthritic Hip Score was 53.4 (range:25–77) and UCLA activity score was 4.2 (range:2–6). For changes in neck length, the mean “Head-centre-to-Greater-trochanteric-tip-distance” was 60 mm (range:43–78) compared to 39 mm (range:30–48) pre-operatively and the mean “Head-center-to-Lesser-trochanteric-tip-distance” was 54 mm (range:47–64) compared to 37 mm (range:31–41) pre-operatively. The mean Tonnis grade was 1.5 (range:1–3) compared to 1.3 (range:1–2) pre-operatively. Two patients underwent arthroplasty conversion at 2 and 13.8 years later. One patient needed head-neck debridement for impingement and 2 patients underwent trochanteric refixation for non-union. There was no progression in avascular necrosis of femoral head. Discussion. Symptomatic Perthes hip deformity in adolescents and young adults is difficult to treat with joint preserving surgery. The mid-term clinical, functional and radiological results for double proximal femur osteotomy are encouraging

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

Introduction: One of the four pillars of successful total knee arthroplasty (TKA) is restoration of the joint line. In conventional TKA the surgeon does not have a tool to control the accuracy of joint line restoration intraoperatively. The present study investigates if the preoperative joint line can be restored using an optical navigation system for TKA. Materials and methods: Patients from two Orthopedic Centers (Istituto Orthopedico Rizzoli Bologna, 51 patients; Orthopädie Samedan, 42 patients) received computer assisted TKA (Stryker Scorpio) using the Stryker Knee navigation system. Using the software delivered with the navigation system depth of femoral and tibial medial and lateral osteotomies were recorded. After definite prosthesis implantation medial and lateral femoral condyle height as well as tibial length including polyethylene inlay were also recorded. Varus/valgus alignment was additionally recorded before and after prosthesis implantation. Results: After femoral osteotomie varus/valgus alignment was 0 degrees (Stdv. 0.6 degrees). Lateral and medial osteotomies were performed with a depth of 8.2 and 8.8 mm respectively. Tibial osteotomie was performed with 0 degrees of varus/valgus (stdv. 0.7 degrees). Lateral and medial tibial osteotomies were performed with a depth of 7.5 and 4.8 mm respectively. After definite prosthesis implantation femoral and tibial varus/valgus alignment was 0.2 degrees of varus (stdv. 0.8 degrees) and 0.1 degrees of varus (stdv. 0.8 degrees) respectively. The femur was lengthened by 0.2 mm (stdy. 3 mm) medially and 1.1 mm (stdy. 3.1 mm) laterally. The tibia was shortened after component implantation by 1.5 mm (stdy. 3.4 mm) medially and 1.1 mm (stdv 3.1 mm) laterally. Discussion: With the use of the Stryker Knee Navigation System, we can reconstruct the preoperative joint line with reproducible accuracy after a TKA. When prosthesis component and polyethylene inlay thickness are known, osteotomies may be performed and corrected intraoperatively to restore the joint line