A retrospective study was performed in 18 patients with achondroplasia, who underwent bilateral humeral lengthening between 2001 and 2013, using monorail external fixators. The mean age was ten years (six to 15) and the mean follow-up was 40 months (12 to 104). . The mean disabilities of the arm, shoulder and hand (DASH) score fell from 32.3 (20 to 40) pre-operatively to 9.4 (6 to 14) post-operatively (p = 0.037). A mean lengthening of 60% (40% to 95%) was required to reach the goal of independent perineal hygiene. One patient developed early consolidation, and fractures occurred in the regenerate bone of four humeri in three patients. There were three transient radial nerve palsies. Humeral lengthening increases the independence of people with achondroplasia and is not just a cosmetic procedure. Cite this article: Bone Joint J 2015;97-B:1577–81

Aims. As an alternative to external fixators, intramedullary lengthening nails (ILNs) can be employed for distraction osteogenesis. While previous studies have demonstrated that typical complications of external devices, such as soft-tissue tethering, and pin site infection can be avoided with ILNs, there is a lack of studies that exclusively investigated tibial distraction osteogenesis with motorized ILNs inserted via an antegrade approach. Methods. A total of 58 patients (median age 17 years (interquartile range (IQR) 15 to 21)) treated by unilateral tibial distraction osteogenesis for a median leg length discrepancy of 41 mm (IQR 34 to 53), and nine patients with disproportionate short stature treated by bilateral simultaneous tibial distraction osteogenesis, with magnetically controlled motorized ILNs inserted via an antegrade approach, were retrospectively analyzed. The median follow-up was 37 months (IQR 30 to 51). Outcome measurements were accuracy, precision, reliability, bone healing, complications, and patient-reported outcome assessed by the Limb Deformity-Scoliosis Research Society Score (LD-SRS-30). Results. A median tibial distraction of 44 mm (IQR 31 to 49) was achieved with a mean distraction index of 0.5 mm/day (standard deviation 0.13) and median consolidation index of 41.2 days/cm (IQR 34 to 51). Accuracy, precision, and reliability were 91%, 92%, and 97%, respectively. New temporary range of motion limitations occurred in 51% of segments (34/67). Distraction-related equinus deformity treated by Achilles tendon lengthening was the most common major complication recorded in 16% of segments (11/67). In 95% of patients (55/58) the distraction goal was achieved with 42% unplanned additional interventions per segment (28/67). The median postoperative LD-SRS-30 score was 4.0 (IQR 3.6 to 4.3). Conclusion. Tibial distraction osteogenesis using motorized ILNs inserted via an antegrade approach appears to be a reliable and precise procedure. Temporary joint stiffness of the knee or ankle should be expected in up to every second patient. A high rate and wide range of complications of variable severity should be anticipated. Cite this article: Bone Joint J 2024;106-B(3):293–302

Aims. The aim of this retrospective cohort study was to assess and investigate the safety and efficacy of using a distal tibial osteotomy compared to proximal osteotomy for limb lengthening in children. Methods. In this study, there were 59 consecutive tibial lengthening and deformity corrections in 57 children using a circular frame. All were performed or supervised by the senior author between January 2013 and June 2019. A total of 25 who underwent a distal tibial osteotomy were analyzed and compared to a group of 34 who had a standard proximal tibial osteotomy. For each patient, the primary diagnosis, time in frame, complications, and lengthening achieved were recorded. From these data, the frame index was calculated (days/cm) and analyzed. Results. All patients ended their treatment with successful lengthening and deformity correction. The frame index for proximal versus distal osteotomies showed no significant difference, with a mean 48.5 days/cm (30 to 85) and 48.9 days/cm (28 to 81), respectively (p = 0.896). In the proximal osteotomy group, two patients suffered complications (one refracture after frame removal and one failure of regenerate maturation with subsequent valgus deformity) compared to zero in the distal osteotomy group. Two patients in each group sustained obstacles that required intervention (one necessitated guided growth, one fibula lengthening, and two required change of wires). There was a similar number of problems (pin-site infections) in each group. Conclusion. Our data show that distal tibial osteotomies can be safely employed in limb lengthening for children using a circular frame, which has implications in planning a surgical strategy; for example, when treating a tibia with shortening and distal deformity, a second osteotomy for proximal lengthening is not required. Cite this article: Bone Joint J 2022;104-B(11):1273–1278

Aims. To systematically review the outcomes and complications of cosmetic stature lengthening. Methods. PubMed and Embase were searched on 10 November 2019 by three reviewers independently, and all relevant studies in English published up to that date were considered based on predetermined inclusion/exclusion criteria. The search was done using “cosmetic lengthening” and “stature lengthening” as key terms. The Preferred Reporting Item for Systematic Reviews and Meta-Analyses statement was used to screen the articles. Results. A total of 11 studies including 795 patients were included. The techniques used in the majority of the patients were classic 3- or 4-ring Ilizarov fixator (267 patients; 33.6%) and lengthening over nail (LON) (253 patients; 31.8%), while implantable lengthening nail (ILN) was used in the smallest number of patients (63 patients; 7.9%). Mean end lengthening achieved was 6.7 cm (SD 0.6; 1.5 to 13.0), and the mean follow-up duration was 4.9 years (SD 2.1; 41 days to 7 years). Overall, the mean number of problems, obstacles, and complications per patient was 0.78 (SD 0.5), 0.94 (SD 1.0), and 0.15 (SD 0.2), respectively. The most common problem and obstacle was ankle equinus deformity, while the most common complications were deformation of the regenerate after end of treatment and subtalar joint stiffness/deformity. Conclusion. Cosmetic stature lengthening provides favourable height gain, patient satisfaction, and functional outcomes, with low rate of major complications. Clear indications, contraindications, and guidelines for cosmetic stature lengthening are needed. Cite this article: Bone Joint Res 2020;9(7):341–350

Aims. Distraction osteogenesis with intramedullary lengthening devices has undergone rapid development in the past decade with implant enhancement. In this first single-centre matched-pair analysis we focus on the comparison of treatment with the PRECICE and STRYDE intramedullary lengthening devices and aim to clarify any clinical and radiological differences. Methods. A single-centre 2:1 matched-pair retrospective analysis of 42 patients treated with the STRYDE and 82 patients treated with the PRECICE nail between May 2013 and November 2020 was conducted. Clinical and lengthening parameters were compared while focusing radiological assessment on osseous alterations related to the nail’s telescopic junction and locking bolts at four different stages. Results. Osteolysis next to the telescopic junction was observed in 31/48 segments (65%) lengthened with the STRYDE nail before implant removal compared to 1/91 segment (1%) in the PRECICE cohort. In the STRYDE cohort, osteolysis initially increased, but decreased or resolved in almost all lengthened segments (86%) after implant removal. Implant failure was observed in 9/48 STRYDE (19%) and in 8/92 PRECICE nails (9%). Breakage of the distal locking bolts was found in 5/48 STRYDE nails (10%) compared to none in the PRECICE cohort. Treatment-associated pain was generally recorded as mild and found in 30/48 patients (63%) and 39/92 (42%) in the STRYDE and PRECICE cohorts, respectively. Temporary range of motion (ROM) limitations under distraction were registered in 17/48 (35%) segments treated with the STRYDE and 35/92 segments (38%) treated with the PRECICE nail. Conclusion. Osteolysis and periosteal reaction, implant breakage, and pain during lengthening and consolidation is more likely in patients treated with the STRYDE nail compared to the PRECICE nail. Temporary ROM limitations during lengthening occurred independent of the applied device. Implant-related osseous alterations seem to remodel after implant removal. Cite this article: Bone Joint J 2023;105-B(1):88–96

Aims. Given the possible radiation damage and inaccuracy of radiological investigations, particularly in children, ultrasound and superb microvascular imaging (SMI) may offer alternative methods of evaluating new bone formation when limb lengthening is undertaken in paediatric patients. The aim of this study was to assess the use of ultrasound combined with SMI in monitoring new bone formation during limb lengthening in children. Methods. In this retrospective cohort study, ultrasound and radiograph examinations were performed every two weeks in 30 paediatric patients undergoing limb lengthening. Ultrasound was used to monitor new bone formation. The number of vertical vessels and the blood flow resistance index were compared with those from plain radiographs. Results. We categorized the new bone formation into three stages: stage I (early lengthening), in which there was no obvious callus formation on radiographs and ultrasound; stage II (lengthening), in which radiographs showed low-density callus formation with uneven distribution and three sub-stages could be identified on ultrasound: in Ia punctate callus was visible; in IIb there was linear callus formation which was not yet connected and in IIc there was continuous linear callus. In stage III (healing), the bone ends had united, the periosteum was intact, and the callus had disappeared, as confirmed on radiographs, indicating healed bone. A progressive increase in the number of vertical vessels was noted in the early stages, peaking during stages IIb and IIc, followed by a gradual decline (p < 0.001). Delayed healing involved patients with a prolonged stage IIa or those who regressed to stage IIa from stages IIb or IIc during lengthening. Conclusion. We found that the formation of new bone in paediatric patients undergoing limb lengthening could be reliably evaluated using ultrasound when combined with the radiological findings. This combination enabled an improved assessment of the prognosis, and adjustments to the lengthening protocol. While SMI offered additional insights into angiogenesis within the new bone, its role primarily contributed to the understanding of the microvascular environment rather than directly informing adjustments of treatment. Cite this article: Bone Joint J 2024;106-B(7):751–758

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. Methods. This is a retrospective single-centre study analyzing outcome of 57 consecutive lengthening procedures performed with the Stryde nail at the authors’ institution from February 2019 until November 2020. Macro- and microscopic metallographic analysis of four retrieved nails was conducted. To investigate observed corrosion at telescoping junction, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) were performed. Results. Adjacent to the nail’s telescoping junction, osteolytic changes were observed in bi-planar radiographs of 20/57 segments (35%) after a mean of 9.5 months (95% confidence interval 7.2 to 11.9) after surgery. A total of 8/20 patients with osseous alterations (40%) reported rest and ambulation pain of the lengthened segment during consolidation. So far, 24 Stryde nails were retrieved and in 20 (83%) macroscopic corrosion was observed at the nail’s telescoping junction. Before implant removal 11/20 radiographs (55%) of lengthened segments with these 20 nails revealed osteolysis. Implant retrieval analysis by means of SEM showed pitting and crevice corrosion. EDX detected chromium as the main metallic element of corrosion. Conclusion. Patients are exposed to the risk of implant-related osteolysis of unclear short- and long-term clinical consequences. The authors advocate in favour of an early implant removal after osseous consolidation. Cite this article: Bone Joint Res 2021;10(7):425–436

Aims. The Precice intramedullary limb-lengthening system has demonstrated significant benefits over external fixation lengthening methods, leading to a paradigm shift in limb lengthening. This study compares outcomes following antegrade and retrograde femoral lengthening in both adolescent and adult patients. Patients and Methods. A retrospective review of prospectively collected data was undertaken of a consecutive series of 107 femoral lengthening operations in 92 patients. In total, 73 antegrade nails and 34 retrograde nails were inserted. Outcome was assessed by the regenerate healing index (HI), hip and knee range of movement (ROM), and the presence of any complications. Results. The mean lengthening was 4.65 cm (1.5 to 8) in the antegrade group and 4.64 cm (1.6 to 8) in the retrograde group. Of the 107 lengthenings, 100 had sufficient datapoints to calculate the mean HI. This was 31.6 days/cm (15 to 108). There was a trend toward a lower (better) HI with an antegrade nail and better outcomes in adolescent patients, but these were not statistically significant. Hip and knee ROM was maintained and/or improved following commencement of femoral lengthening in 44 patients (60%) of antegrade nails and 13 patients (38%) of retrograde nails. In female patients, loss of movement occurred both earlier and following less total length achieved. Minor implant complications included locking bolt migration and in one patient deformity of the nail, but no implant failed to lengthen and there were no deep infections. Three patients had delayed union, five patients required surgical intervention for joint contracture. Conclusion. This study confirms excellent results in femoral lengthening with antegrade and retrograde Precice nails. There is a trend for better healing and less restriction in hip and knee movement following antegrade nails. There are clinical scenarios, that mandate the use of a retrograde nail. However, when these are not present, we recommend the use of antegrade nailing. Cite this article: Bone Joint J 2019;101-B:1168–1176

Limb lengthening is used to correct leg length discrepancy and to increase stature. The reported frequency of peripheral nerve complications varies from 5% to 30%, but is probably underestimated. Damage may be direct or be caused by overstretching of the nerves. We have used electrophysiological tests to evaluate five patients during bilateral tibial lengthening by the Ilizarov method. Results after 24 to 107 days of lengthening showed electromyographic evidence of partial muscle denervation in all 10 limbs, with reduced motor conduction velocities in two tibial nerves and three common peroneal nerves. The sensory conduction velocity in the sural nerve was always unchanged. A clear relationship was shown between the amount of tibial lengthening and the degree of electrophysiological abnormality. Our results suggest that subclinical nerve damage is a very frequent complication of tibial lengthening

Aims. The aim of this study was to evaluate the kinematics of the elbow following increasing length of the radius with implantation of radial head arthroplasties (RHAs) using dynamic radiostereometry (dRSA). Methods. Eight human donor arms were examined by dRSA during motor-controlled flexion and extension of the elbow with the forearm in an unloaded neutral position, and in pronation and supination with and without a 10 N valgus or varus load, respectively. The elbows were examined before and after RHA with stem lengths of anatomical size, + 2 mm, and + 4 mm. The ligaments were maintained intact by using a step-cut lateral humeral epicondylar osteotomy, allowing the RHAs to be repeatedly exchanged. Bone models were obtained from CT scans, and specialized software was used to match these models with the dRSA recordings. The flexion kinematics of the elbow were described using anatomical coordinate systems to define translations and rotations with six degrees of freedom. Results. The greatest kinematic changes in the elbows were seen with the longest, + 4 mm, implant, which imposed a mean joint distraction of 2.8 mm in the radiohumeral joint and of 1.1 mm in the ulnohumeral joint, an increased mean varus angle of up to 2.4° for both the radius and the ulna, a mean shift of the radius of 2.0 mm in the ulnar direction, and a mean shift of the ulna of 1.0 mm posteriorly. Conclusion. The kinematics of the elbow deviated increasingly from those of the native joint with a 2 mm to a 4 mm lengthening of the radius. This confirms the importance of restoring the natural length of the radius when undertaking RHA. Cite this article: Bone Joint J 2024;106-B(10):1165–1175

Aims. Patients undergoing femoral lengthening by external fixation tolerate treatment less well when compared to tibial lengthening. Lengthening of the femur with an intramedullary device may have advantages. Patients and Methods. We reviewed all cases of simple femoral lengthening performed at our unit from 2009 to 2014. Cases of nonunions, concurrent deformities, congenital limb deficiencies and lengthening with an unstable hip were excluded, leaving 33 cases (in 22 patients; 11 patients had bilateral procedures) for review. Healing index, implant tolerance and complications were compared. Results. In 20 cases (15 patients) the Precice lengthening nail was used and in 13 cases (seven patients) the LRS external fixator system. The desired length was achieved in all cases in the Precice group and in 12 of 13 cases in the LRS group. The mean healing index was 31.3 days/cm in the Precice and 47.1 days/cm in the LRS group (p < 0.001). This was associated with an earlier ability to bear full weight without aids in the Precice group. There were more complications with LRS lengthening, including pin site infections and regenerate deformity. Implant tolerance and the patients’ perception of the cosmetic result were better with the Precice treatment. Conclusion. Femoral lengthening with the Precice femoral nail achieved excellent functional results with fewer complications and greater patient satisfaction when compared with the LRS system in our patients. Cite this article: Bone Joint J 2016;98-B:1382–8

Objectives. The Precice nail is the latest intramedullary lengthening nail with excellent early outcomes. Implant complications have led to modification of the nail design. The aim of this study was to perform a retrieval study of Precice nails following lower-limb lengthening and to assess macroscopical and microscopical changes to the implants and evaluate differences following design modification, with the aim of identifying potential surgical, implant, and patient risk factors. Methods. A total of 15 nails were retrieved from 13 patients following lower-limb lengthening. Macroscopical and microscopical surface damage to the nails were identified. Further analysis included radiology and micro-CT prior to sectioning. The internal mechanism was then analyzed with scanning electron microscopy and energy dispersive x-ray spectroscopy to identify corrosion. Results. Seven male and three female patients underwent 12 femoral lengthenings. Three female patients underwent tibial lengthening. All patients obtained the desired length with no implant failure. Surface degradation was noted on the telescopic part of every nail design, less on the latest implants. Microscopical analysis confirmed fretting and pitting corrosion. Following sectioning, black debris was noted in all implants. The early designs were found to have fractured actuator pins and the pin and bearings showed evidence of corrosive debris. The latest designs showed evidence of biological deposits suggestive of fluid ingress within the nail but no corrosion. Conclusion. This study confirms less internal corrosion following modification, but evidence of titanium debris remains. We recommend no change to current clinical practice. However, potential reuse of the Precice nail, for secondary limb lengthening in the same patient, should be undertaken with caution. Cite this article: V. C. Panagiotopoulou, K. Davda, H. S. Hothi, J. Henckel, A. Cerquiglini, W. D. Goodier, J. Skinner, A. Hart, P. R. Calder. A retrieval analysis of the Precice intramedullary limb lengthening system. Bone Joint Res 2018;7:476–484. DOI: 10.1302/2046-3758.77.BJR-2017-0359.R1

Objectives. The purpose of this study was to compare the results and complications of tibial lengthening over an intramedullary nail with treatment using the traditional Ilizarov method. Methods. In this matched case study, 16 adult patients underwent 19 tibial lengthening over nails (LON) procedures. For the matched case group, 17 patients who underwent 19 Ilizarov tibial lengthenings were retrospectively matched to the LON group. Results. The mean external fixation time for the LON group was 2.6 months and for the matched case group was 7.6 months. The mean lengthening amounts for the LON and the matched case groups were 5.2 cm and 4.9 cm, respectively. The radiographic consolidation time in the LON group was 6.6 months and in the matched case group 7.6 months. Using a clinical and radiographic outcome score that was designed for this study, the outcome was determined to be excellent in 17 and good in two patients for the LON group. The outcome was excellent in 14 and good in five patients in the matched case group. The LON group had increased blood loss and increased cost. The LON group had four deep infections; the matched case group did not have any deep infections. Conclusions. The outcomes in the LON group were comparable with the outcomes in the matched case group. The LON group had a shorter external fixation time but experienced increased blood loss, increased cost, and four cases of deep infection. The advantage of reducing external fixation treatment time may outweigh these disadvantages in patients who have a healthy soft-tissue envelope. Cite this article: J. E. Herzenberg. Tibial lengthening over intramedullary nails: A matched case comparison with Ilizarov tibial lengthening. Bone Joint Res 2016;5:1–10. doi: 10.1302/2046-3758.51.2000577

Extensive limb lengthening may be indicated in achondroplastic patients who wish to achieve a height within the normal range for their population. However, increasing the magnitude of lengthening is associated with further complications particularly adjacent joint stiffness and fractures. We studied the relationship between the magnitude of femoral lengthening and callus pattern, adjacent joint stiffness and fracture of the regenerate bone in 40 femoral lengthenings in 20 achondroplastic patients. They were divided into two groups; group A had lengthening of less than 50% and group B of more than 50% of their initial femoral length. The patterns of radiological callus formation were classified according to shape, type and features. The incidence of callus features, knee stiffness and regenerate bone fracture were analysed in the two groups. Group B was associated with an increased incidence of concave, lateral and central callus shapes, adjacent joint and stiffness and fracture. Statistically, the incidence of stiffness in adjacent joints and regenerate bone fracture was significantly associated with the magnitude of lengthening. We suggest that careful radiological assessment of the patterns of callus formation is a useful method for the evaluation and monitoring of regenerate bone

Aims. The aim of this study was to describe, analyze, and compare the survival, functional outcome, and complications of minimally invasive (MI) and non-invasive (NI) lengthening total femoral prostheses. Patients and Methods. A total of 24 lengthening total femoral prostheses, 11 MI and 13 NI, were implanted between 1991 and 2016. The characteristics, complications, and functional results were recorded. There were ten female patients and ten male patients. Their mean age at the time of surgery was 11 years (2 to 41). The mean follow-up was 13.2 years (seven months to 29.25 years). A survival analysis was performed, and the failures were classified according to the Modified Henderson System. Results. The overall implant survival was 79% at five, ten, and 20 years for MI prostheses, and 84% at five years and 70% at ten years for NI prostheses. At the final follow-up, 13 prostheses did not require further surgery. The overall complication rate was 46%. The mean revision-free implant survival for MI and NI prostheses was 59 months and 49 months, respectively. There were no statistically significant differences in the overall implant survival, revision-free survival, or the distribution of complications between the two types of prosthesis. Infection rates were also comparable in the groups (9% vs 7%; p = 0.902). The rate of leg-length discrepancy was 54% in MI prostheses and 23% in NI prostheses. In those with a MI prosthesis, there was a smaller mean range of movement of the knee (0° to 62° vs 0° to 83°; p = 0.047), the flexion contracture took a longer mean time to resolve after lengthening (3.3 months vs 1.07 months; p < 0.001) and there was a lower mean Musculoskeletal Tumor Society (MSTS) score (24.7 vs 27; p = 0.295). Conclusion. The survival and complications of MI and NI lengthening total femoral prostheses are comparable. However, patients with NI prosthesis have more accurate correction of leg-length discrepancy, a better range of movement of the knee and an improved overall function

We present our experience of forearm lengthening in children with various conditions performed by a single surgeon between 1995 and 2009. A total of 19 children with a mean age of 9.8 years (2.1 to 15.9) at the time of surgery had 22 forearm lengthenings using either an Ilizarov/spatial and Ilizarov circular frame or a monolateral external fixator. The patients were divided into two groups: group A, in whom the purpose of treatment was to restore the relationship between the radius and the ulna, and group B, in whom the objective was to gain forearm length. The mean follow-up after removal of the frame was 26 months (13 to 53). There were ten patients (11 forearms) in group A with a mean radioulnar discrepancy of 2.4 cm (1.5 to 3.3) and nine patients (11 forearms) in group B. In group A, the mean lengthening achieved was 2.7 cm (1.0 to 5.5), with a lengthening index of 11.1 weeks/cm. Equalisation or overcorrection of the discrepancy was achieved in seven of 11 forearms, but lengthening was only partially successful at preventing subluxation or dislocation of the radial head. In group B, the mean lengthening achieved was 3.8 cm (1.9 to 6.8), with a lengthening index of 7.25 weeks/cm. Common complications in both groups were pin-site infection and poor regenerate formation. Forearm lengthening by distraction osteogenesis is a worthwhile procedure in children that can improve cosmesis and function, particularly in patients with shortening of both radius and ulna

Aims. We wished to examine the effectiveness of tibial lengthening using a two ring Ilizarov frame in skeletally immature patients. This is a potentially biomechanically unstable construct which risks the loss of axial control. Patients and Methods. We retrospectively reviewed a consecutive series of 24 boys and 26 girls, with a mean age of 8.6 years (4 to 14), who underwent 52 tibial lengthening procedures with a mean follow-up of 4.3 years (4.0 to 16.9). Tibial alignment was measured before and after treatment using joint orientation lines from the knee and a calculation of the oblique plane axis. Results. The mean percentage length gain was 20% (13 to 31) with a mean bone-healing index (BHI) of 34 days per centimetre (20 to 54). Age at surgery and location of the osteotomy site showed a strong relationship as the location of the osteotomy migrated more proximally with age. However, no significant correlation was found between BHI and the position of the osteotomy. The coronal and sagittal joint orientation of the lengthened tibias were within the normal range in 67% and 92% of cases, respectively. The oblique plane angulation calculation revealed a statistically significant change pre- to post-operatively in both magnitude (p < 0.05) and direction (p < 0.01), but without clinical consequence. The majority of complications were minor (n = 40 in 27 patients; 1.48 complications per segment lengthened) with no residual disability reported. Conclusion. Two-ring tibial lengthening is effective in maintaining segmental alignment, efficient in callous production and relatively comfortable for the patient with few significant complications. Cite this article: Bone Joint J 2016;98-B:1276–82

Femoral lengthening using the Intramedullary Skeletal Kinetic Distractor is a new technique. However, with intramedullary distraction the surgeon has less control over the lengthening process. Therefore, 33 femora lengthened with this device were assessed to evaluate the effect of operative variables under the surgeon’s control on the course of lengthening. The desired lengthening was achieved in 32 of 33 limbs. Problems encountered included difficulty in achieving length in eight femora (24%) and uncontrolled lengthening in seven (21%). Uncontrolled lengthening was more likely if the osteotomy was placed with less than 80 mm of the thick portion of the nail in the distal fragment (p = 0.052), and a failure to lengthen was more likely if there was over 125 mm in the distal fragment (p = 0.008). The latter problem was reduced with over-reaming by 2.5 mm to 3 mm. Previous intramedullary nailing also predisposed to uncontrolled lengthening (p = 0.042), and these patients required less reaming. Using the Intramedullary Skeletal Kinetic Distractor, good outcomes were obtained; problems were minimised by optimising the position of the osteotomy and the amount of over-reaming performed

Little is known about the increase in length of tendons in postnatal life or of their response to limb lengthening procedures. A study was carried out in ten young and nine adult rabbits in which the tibia was lengthened by 20% at two rates 0.8 mm/day and 1.6 mm/day. The tendon of the flexor digitorum longus (FDL) muscle showed a significant increase in length in response to lengthening of the tibia. The young rabbits exhibited a significantly higher increase in length in the FDL tendon compared with the adults. There was no difference in the amount of lengthening of the FDL tendon at the different rates. Of the increase in length which occurred, 77% was in the proximal half of the tendon. This investigation demonstrated that tendons have the ability to lengthen during limb distraction. This occurred to a greater extent in the young who showed a higher proliferative response, suggesting that there may be less need for formal tendon lengthening in young children

The Ilizarov method for leg lengthening was used for cosmetic reasons in 54 patients with constitutional short stature. A mean lengthening of 7 cm with a low rate of complications produced an excellent or good outcome in all the patients, including improvement in psychological disturbances related to short stature. Those who undergo the procedure must be highly motivated, fully informed and understand the technique and possible complications. We suggest that the Ilizarov method for cosmetic limb lengthening is a technique without major complications. However, it requires careful follow-up, and the involvement of orthopaedic surgeons who are familiar with use of the circular frame and are experienced in limb lengthening and correction of deformity for pathological conditions