Objectives. Distraction osteogenesis (DO) mobilises bone regenerative potential and avoids the complications of other treatments such as bone graft. The major disadvantage of DO is the length of time required for bone consolidation. Mesenchymal stem cells (MSCs) have been used to promote bone formation with some good results. Methods. We hereby review the published literature on the use of MSCs in promoting bone consolidation during DO. Results. Studies differed in animal type (mice, rabbit, dog, sheep), bone type (femur, tibia, skull), DO protocols and cell transplantation methods. Conclusion. The majority of studies reported that the transplantation of MSCs enhanced bone consolidation or formation in DO. Many questions relating to animal model, DO protocol and cell transplantation regime remain to be further investigated. Clinical trials are needed to test and confirm these findings from animal studies. Cite this article: Y. Yang, S. Lin, B. Wang, W. Gu, G. Li. Stem cell therapy for enhancement of bone consolidation in distraction osteogenesis: A contemporary review of experimental studies. Bone Joint Res 2017;6:385–390. DOI: 10.1302/2046-3758.66.BJR-2017-0023

Aims. The aim of this study was to describe the technique of distraction osteogenesis followed by arthrodesis using internal fixation to manage complex conditions of the ankle, and to present the results of this technique. Patients and Methods. Between 2008 and 2014, distraction osteogenesis followed by arthrodesis using internal fixation was performed in 12 patients with complex conditions of the ankle due to trauma or infection. There were eight men and four women: their mean age was 35 years (23 to 51) at the time of surgery. Bone healing and functional recovery were evaluated according to the criteria described by Paley. Function was assessed using the ankle-hindfoot scale of the American Orthopedic Foot and Ankle Society (AOFAS). Results. A solid fusion of the ankle and eradication of infection was achieved in all patients. A mean lengthening of 6.1 cm (2.5 to 14) was achieved at a mean follow-up of 25.2 months (14 to 37). The mean external fixation index (EFI) was 42 days/cm (33.3 to 58). The function was judged to be excellent in six patients and good in six patients. Bone results were graded as excellent in ten patients and good in two patients. The mean AOFAS score was 37.3 (5 to 77) preoperatively and 75.3 (61 to 82) at the final follow-up. Minor complications, which were treated conservatively, included pain, pin-tract infection, loosening of wires, and midfoot stiffness. Major complications, which were treated surgically included grade V pin-tract infection with inflammation and osteolysis, poor consolidation of the regenerate bone, and soft-tissue invagination. The reoperations required to treat the major complications included the exchange of pins and wires, bone grafting and invagination split surgery. Conclusion. The technique of distraction osteogenesis followed by arthrodesis using internal fixation is an effective form of treatment for the management of complex conditions of the ankle. It offers a high rate of union, an opportunity to remove the frame early, and a reduced EFI without infection or wound dehiscence. Cite this article: Bone Joint J 2018;100-B:755–60

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. Methods. The effects of a HSR PEMF signal with three daily treatment durations (0.5, one, and three hours/day) were investigated in an established rat DO model with comparison of an FDA-approved classic signal (three hrs/day). PEMF treatments were applied to the rats daily for 35 days, starting from the distraction phase until termination. Radiography, micro-CT (μCT), biomechanical tests, and histological examinations were employed to evaluate the quality of bone formation. Results. All rats tolerated the treatment well and no obvious adverse effects were found. By comparison, the HSR signal (three hrs/day) treatment group achieved the best healing outcome, in that endochondral ossification and bone consolidation were enhanced. In addition, HSR signal treatment (one one hr/day) had similar effects to treatment using the classic signal (three three hrs/day), indicating that treatment duration could be significantly shortened with the HSR signal. Conclusion. HSR signal may significantly enhance bone formation and shorten daily treatment duration in DO, making it a potential candidate for a new clinical protocol for patients undergoing DO treatments. Cite this article: Bone Joint Res 2021;10(12):767–779

We carried out a systematic review of the literature to evaluate the evidence regarding the clinical results of the Ilizarov method in the treatment of long bone defects of the lower limbs. Only 37 reports (three non-randomised comparative studies, one prospective study and 33 case-series) met our inclusion criteria. Although several studies were unsatisfactory in terms of statistical heterogeneity, our analysis appears to show that the Ilizarov method of distraction osteogenesis significantly reduced the risk of deep infection in infected osseous lesions (risk ratio 0.14 (95% confidence interval (CI) 0.10 to 0.20), p < 0.001). However, there was a rate of re-fracture of 5% (95% CI 3 to 7), with a rate of neurovascular complications of 2.2% (95% CI 0.3 to 4) and an amputation rate of 2.9% (95% CI 1.4 to 4.4).The data was generally not statistically heterogeneous. Where tibial defects were > 8 cm, the risk of re-fracture increased (odds ratio 3.7 (95% CI 1.1 to 12.5), p = 0.036). . The technique is demanding for patients, illustrated by the voluntary amputation rate of 1.6% (95% CI 0 to 3.1), which underlines the need for careful patient selection. Cite this article: Bone Joint J 2013;95-B:1673–80

Aims

In this randomized study, we aimed to compare quality of regenerate in monolateral versus circular frame fixation in 30 patients with infected nonunion of tibia.

Aims

This is a prospective randomised study which compares the radiological and functional outcomes of ring and rail fixators in patients with an infected gap (> 3 cm) nonunion of the tibia.

Aims. The aim of this double-blind prospective randomised controlled trial was to assess whether low intensity pulsed ultrasound (LIPUS) accelerated or enhanced the rate of bone healing in adult patients undergoing distraction osteogenesis. Patients and Methods. A total of 62 adult patients undergoing limb lengthening or bone transport by distraction osteogenesis were randomised to treatment with either an active (n = 32) or a placebo (n = 30) ultrasound device. A standardised corticotomy was performed in the proximal tibial metaphysis and a circular Ilizarov frame was used in all patients. The rate of distraction was also standardised. The primary outcome measure was the time to removal of the frame after adjusting for the length of distraction in days/cm for both the per protocol (PP) and the intention-to-treat (ITT) groups. The assessor was blinded to the form of treatment. A secondary outcome was to identify covariates affecting the time to removal of the frame. Results. There was no difference in the time to removal of the frame between the PP (difference in favour of the control group was 10.1 days/cm, 95% confidence interval (CI) -3.2 to 23.4, p = 0.054) or ITT (difference 5.0 days/cm, 95% CI -8.2 to 18.21, p = 0.226) groups. The smoking status was the only covariate which increased the time to removal of the frame (hazard ratio 0.47, 95% CI 0.22 to 0.97, p = 0.042). Conclusion. LIPUS does not influence the rate of bone healing in patients who undergo distraction osteogenesis. Smoking may influence bone healing. . Cite this article: Bone Joint J 2017;99-B:494–502

We undertook a retrospective study of 50 consecutive patients (41 male, 9 female) with an infected nonunion and bone defect of the femoral shaft who had been treated by radical debridement and distraction osteogenesis. Their mean age was 29.9 years (9 to 58) and they had a mean of 3.8 (2 to 19) previous operations. They were followed for a mean of 5.9 years (2.0 to 19.0). The mean duration of the distraction osteogenesis was 24.5 months (2 to 39). Pin-track infection was observed in all patients. The range of knee movement was reduced and there was a mean residual leg-length discrepancy of 1.9 cm (0 to 8) after treatment. One patient required hip disarticulation to manage intractable sepsis. In all, 13 patients had persistant pain. Bony union was achieved in 49 patients at a mean of 20.7 months (12 to 35). Although distraction osteogenesis is commonly used for the treatment of infected femoral nonunion with bone defects, it is associated with a high rate of complications

Distraction osteogenesis (callotasis) has been widely used in patients with limb-length inequality or massive bone defects. This procedure, however, may be associated with a high incidence of physical and psychosocial complications. Callotasis telescoping on a locked intramedullary nail has been used to shorten the period of external fixation. Little attention has been given to the use of locked intramedullary nails in the treatment of complications after callotasis. Between 1990 and 1999, we used locked intramedullary nailing in 27 patients for the treatment of complications after distraction osteogenesis. There were 17 men and ten women with a mean age of 33.2 years (16 to 66). The nail was inserted at a mean of 3.4 weeks (0 to 15) after removal of the external fixator. Simultaneous autogenous bone grafting and soft-tissue reconstruction were also undertaken in seven and two patients, respectively. There was consolidation of the callus or docking site in all patients at a mean of 6.4 months (2 to 14) after surgery. The mean shortening of the callus was 0.7 cm (0 to 2.5). Two patients had infection at the site of a distal screw which resolved after removal of the nail. In 17 patients the nail was removed at a mean of 26 months after its insertion. Locked intramedullary nails are useful in treating complications after distraction osteogenesis in skeletally mature patients. The risk of infection should be borne in mind

We investigated the effect of locally administered bisphosphonate on distraction osteogenesis in a rabbit model and evaluated its systemic effect. An osteotomy on the right tibia followed by distraction for four weeks was performed on 47 immature rabbits. They were divided into seven equal groups, with each group receiving a different treatment regime. Saline and three types of dosage of alendronate (low, 0.75 μg/kg; mid, 7.5 μg/kg and high 75 μg/kg) were given by systemic injection in four groups, and saline and two dosages (low and mild) were delivered by local injection to the distraction gap in the remaining three groups. The injections were performed five times weekly during the period of distraction. After nine weeks the animals were killed and image analysis and mechanical testing were performed on the distracted right tibiae and the left tibiae which served as a control group. The local low-dose alendronate group showed a mean increase in bone mineral density of 124.3 mg/cm. 3. over the local saline group (analysis of variance, p < 0.05) without any adverse effect on the left control tibiae. The findings indicate that the administration of local low-dose alendronate could be an effective pharmacological means of improving bone formation in distraction osteogenesis

We investigated the effects of low-intensity pulsed ultrasound on distraction osteogenesis in a rabbit model. Callotasis of the right tibia was performed in 70 male Japanese white rabbits using mini-external fixators. In the first part of the study in 64 animals using normal distraction (waiting period seven days; distraction rate 0.5 mm/12 hours; distraction period ten days), we evaluated the distraction site by radiography, measurement of the bone mineral density (BMD), mechanical testing, and histology. In the second part in six rabbits using fast distraction (waiting period 0 days; distraction rate 1.5 mm/12 hours; distraction period seven days) the site was evaluated radiologically. Half of the animals (35) had received ultrasound to their right leg (30mW/cm. 2. ) for 20 minutes daily after ceasing distraction (ultrasound group), while rigid fixation only was maintained in the other half (control group). With normal distraction, the hard callus area, as shown by radiography, the BMD, and the findings on mechanical testing, were significantly greater in those receiving ultrasound than in the control group. Histological analysis showed no tissue damage attributable to exposure to ultrasound. With fast distraction, immature bone regeneration was observed radiologically in the control group, while bone maturation was achieved in the ultrasound group. We conclude that ultrasound can accelerate bone maturation in distraction osteogenesis in rabbits, even in states of poor callotasis

We reviewed 173 patients undergoing distraction osteogenesis to determine the incidence, location and timing of fractures occurring as a complication of the procedure. There were 17 fractures in 180 lengthened segments giving an overall rate of fracture of 9.4%. Unexpectedly, the pattern and location of the fractures were very variable; six were within the regenerate itself, six at the junction between the regenerate and the original bone and five at distant sites in the limb. Of those occurring in the regenerate, five were noted to be associated with compression and partial collapse of the regenerate. In three patients collapse and deformity developed gradually in the distracted segment over the six months after removal of the frame. The method of treatment of these fractures should be chosen to take into account multiple factors, which are additional and often different from those to be considered during management of acute traumatic injuries. Internal fixation appears to be most appropriate for displaced fractures, although in small children, or in those in whom there has been, or is, infection of the screw tracks, a new period of treatment using external fixation may be needed. Fixation by intramedullary nailing was associated with a risk of infection, even if screw tracks were assessed as healthy at the time of insertion of the nail. Internal fixation with the use of plates is safe for displaced, unstable fractures in children

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

Seven children with a post-traumatic cubitus varus deformity were treated using the Ilizarov technique of distraction osteogenesis. The outcome was rated as excellent in each case and all were satisfied with the cosmetic appearance. No complications had been encountered by the latest follow-up at a mean of 66.7 months. This technique seems reliable for the treatment of such deformities, provided that it achieves full correction by gradual distraction. Nerve palsy and unsightly scars are avoided, and the range of movement of adjacent joints is preserved

We examined the effect on bone mineral density (BMD) of a single dose of 3 mg/kg of the bisphosphonate, pamidronate (Novartis) in distraction osteogenesis in immature rabbits. Seventeen rabbits (9 control, 8 given pamidronate) were examined by dual-energy x-ray absorptiometry. There was a significant increase in the BMD in the pamidronate group compared with the control animals. The mean areal BMD (g/cm. 2. ) in the bone proximal and distal to the regenerate was increased by 40% and 39%, respectively, compared with the control group (p < 0.05). The BMD of the regenerate bone was increased by a mean of 43% (p < 0.05). There was an increase of 22% in the mean area of regenerate formed in the pamidronate group (p< 0.05). Histological examination of bone in nine rabbits (5 control, 4 pamidronate) showed an increase in osteoblastic rimming and mineralisation of the regenerate, increased formation of bone around the pin sites and an increase in the cortical width of the bone adjacent to the regenerate in the rabbits given pamidronate. Pamidronate had a markedly positive effect. It reduced the disuse osteoporosis normally associated with lengthening using an external fixator and increased the amount and density of the regenerate bone. Further study is required to examine the mechanical properties of the regenerate after the administration of pamidronate

Aims. The management of a significant bony defect following excision of a diaphyseal atrophic femoral nonunion remains a challenge. We present the outcomes using a combined technique of acute femoral shortening, stabilized with a long retrograde intramedullary nail, accompanied by bifocal osteotomy compression and distraction osteogenesis with a temporary monolateral fixator. Patients and Methods. Eight men and two women underwent the ‘rail and nail’ technique between 2008 and 2016. Proximal locking of the nail and removal of the external fixator was undertaken once the length of the femur had been restored and prior to full consolidation of the regenerate. Results. The mean lengthening was 7 cm (3 to 11). The external fixator was removed at a mean of 127 days (57 to 220). The mean bone healing index was 28 days/cm and the mean external fixation index was 20 days/cm (11 to 18). There were no superficial or deep infections. Conclusion. This small retrospective study shows encouraging results for a combined technique, enabling compression of the femoral osteotomy, alignment, and controlled lengthening. Removal of the fixator and proximal locking of the nail reduces the risk of complications and stabilizes the femur with the maximum working length of the nail. Cite this article: Bone Joint J 2018;100-B:634–9

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

We describe three cases of infantile tibia vara resulting from an atraumatic slip of the proximal tibial epiphysis upon the metaphysis. There appears to be an association between this condition and severe obesity. Radiologically, the condition is characterised by a dome-shaped metaphysis, an open growth plate and disruption of the continuity between the lateral borders of the epiphysis and metaphysis, with inferomedial translation of the proximal tibial epiphysis. All patients were treated by realignment of the proximal tibia by distraction osteogenesis with an external circulator fixator, and it is suggested that this is the optimal method for correction of this complex deformity. There are differences in the radiological features and management between conventional infantile Blount’s disease and this ‘slipped upper tibial epiphysis’ variant

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.