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 response of the muscle is critical in determining the functional outcome of limb lengthening. We hypothesised that muscle response would vary with age and therefore studied the response of the muscles during tibial lengthening in ten young and ten mature rabbits. A bromodeoxyuridine technique was used to identify the dividing cells. The young rabbits demonstrated a significantly greater proliferative response to the distraction stimulus than the mature ones. This was particularly pronounced at the myotendinous junction, but was also evident within the muscle belly. Younger muscle adapted better to lengthening, suggesting that in patients in whom a large degree of muscle lengthening is required it may be beneficial to carry out this procedure when they are young, in order to achieve the optimal functional result

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.

Osteomyelitis is an inflammatory condition accompanied by the destruction of bone and caused by an infecting microorganism. Open contaminated fractures can lead to the development of osteomyelitis of the fractured bone in 3-25% of cases, depending on fracture type, degree of soft-tissue injury, degree of microbial contamination, and whether systemic and/or local antimicrobial therapies have been administered. Untreated, infection will ultimately lead to non-union, chronic osteomyelitis, or amputation. We report a case series of 10 patients that presented with post-operative infected non-union of the distal femur with or without prior surgery. The cases were performed at Padmashree Dr. D. Y. Patil Hospital, Nerul, Navi Mumbai, India. All the patients’ consents were taken for the study which was carried out in accordance with the Helsinki Declaration. The methodology involved patients undergoing a two-stage procedure in case of no prior implant or a three-stage procedure in case of a previous implant. Firstly, debridement and implant removal were done. The second was a definitive procedure in form of knee arthrodesis with ring fixator and finally followed by limb lengthening surgery. Arthrodesis was planned in view of infection, non-union, severe arthritic, subluxated knee, stiff knee, non-salvage knee joint, and financial constraints. After all the patients demonstrated wound healing in 3 months along with good radiographic osteogenesis at the knee arthrodesis site, limb lengthening surgeries by tibial osteotomy were done to overcome the limb length discrepancy. Distraction was started and followed up for 5 months. All 10 patients showed results with sound knee arthrodesis and good osteogenesis at the osteotomy site followed by achieving the limb length just 1-inch short from the normal side to achieve ground clearance while walking. Our case series is unique and distinctive as it shows that when patients with infected nonunion of distal femur come with the stiff and non-salvage knee with severe arthritic changes and financial constraints, we should consider knee arthrodesis with Ilizarov ring fixator followed by limb lengthening surgery

Introduction. The recent introduction of Chatbots has provided an interactive medium to answer patient questions. The accuracy of responses with these programs in limb lengthening and reconstruction surgery has not previously been determined. Therefore, the purpose of this study was to assess the accuracy of answers from 3 free AI chatbot platforms to 23 common questions regarding treatment for limb lengthening and reconstruction. Method. We generated a list of 23 common questions asked by parents before their child's limb lengthening and reconstruction surgery. Each question was posed to three different AI chatbots (ChatGPT 3.5 [OpenAI], Google Bard, and Microsoft Copilot [Bing!]) by three different answer retrievers on separate computers between November 17 and November 18, 2023. Responses were only asked one time to each chatbot by each answer retriever. Nine answers (3 answer retrievers × 3 chatbots) were randomized and platform-blinded prior to rating by three orthopedic surgeons. The 4-point rating system reported by Mika et al. was used to grade all responses. Result. ChatGPT had the best response accuracy score (RAS) with a mean score of 1.73 ± 0.88 across all three raters (range of means for all three raters – 1.62 – 1.81) and a median score of 2. The mean response accuracy scores for Google Bard and Microsoft Copilot were 2.32 ± 0.97 and 3.14 ± 0.82, respectively. This ranged from 2.10 – 2.48 and 2.86 – 3.54 for Google Bard and Microsoft Copilot, respectively. The differences between the mean RAS scores were statistically significant (p < 0.0001). The median scores for Google Bard and Microsoft Copilot were 2 and 3, respectively. Conclusion. Using the Response Accuracy Score, the responses from ChatGPT were determined to be satisfactory, requiring minimal clarification, while the responses from Microsoft Copilot were either satisfactory, requiring moderate clarification, or unsatisfactory, requiring substantial clarification

Introduction. Previous studies have shown the potential for virtual reality (VR) immersion as a promising technique for pain and anxiety management. The aim of our study was to evaluate the feasibility of VR in the management of pain and anxiety during post-op external fixator care procedures. Method. This study involved patients aged 5-21 years following limb lengthening/reconstruction surgery with an external fixator. Aqua VR application from the KindVR® was utilized for this study. Subjects were seen during the first four postoperative visits and assigned to a ‘VR-first’ or ‘no-VR-first’ group. Visits alternated between VR immersion and no VR immersion during care procedures. The study endpoints (pain and anxiety levels) were assessed before, during, and after procedures using the Wong-Baker Faces (FACES) and Children's Fear Scale, respectively. Proxy scores for pain and anxiety were also obtained from parents or legal guardians and providers. Result. A total of 29 patients (16 male and 13 female) were evaluated. The mean age at enrollment was 14.4 ± 2.2 years for group 1 and 14.7 ± 4.0 years for group 2. The median number of pin sites was 7. Anxiety scores were consistently higher during the non-VR immersion experience compared to the VR immersion visits. The pain and anxiety scores were significantly lower in the ‘VR-first’ group during the non-VR immersion study visits compared to patients in the ‘no-VR-first’ group. This observation was also consistent with survey findings among the parent proxies and providers. Conclusion. VR immersion is associated with lower anxiety scores for pin-site care procedures. VR immersion at the first post-operative visit following limb reconstruction surgery was also associated with lower pain and anxiety scores during subsequent non-VR immersion visits

Introduction. Pediatric femoral fracture including supracondylar and subtrochantric fracture constitutes 1.6% of all pediatrics fractures. 1. Elastic nails remain the standard treatment of choice in mid shaft transverse femoral fracture in children weighting less than 45kg. 2. But in subtrochantric and spiral femoral fracture, failure rate of TENS nails are quite high. 3. . Material and methods. We retrospectively reviewed 30 subtrochantric fracture in children (average age 9 years) treated with bridge plate by mini invasive approach. Result. All fracture united well in average 14 weeks. Single complication was 5mm limb lengthening due to fixation in traction on fracture table in one case. We strongly recommend bridge plate in complex femoral fracture in children

We carried out limb lengthening in rabbits and then transplanted osteoblast-like cells derived from the tibial periosteum to the centres of distracted callus immediately after distraction had been terminated. Two weeks later the transaxial area ratio at the centre of the distracted callus and the bone mineral density (BMD) were significantly higher in the transplanted group, by 21% and 42%, respectively, than in the non-injected group or the group injected with physiological saline (p < 0.05). Callus BMD as a percentage of density in uninvolved bone was also significantly higher in the transplanted group (p < 0.05) than in the other two groups, by 27% and 20% in the second and fourth weeks, respectively (p < 0.05). Mechanically, the callus in the transplanted group tended to be stronger as shown by the three-point bending test although the difference in fracture strength was not statistically significant. Our results show that transplantation of osteoblast-like cells promotes maturity of the distracted callus as observed at the second and fourth weeks after lengthening. The method appears promising as a means of shortening the consolidation period of callus distraction and decreasing complications during limb lengthening with an external fixator

Shortness of an extremity due to different causes is an issue that may adversely affect human life functional and psychologically. In this study, in the light of previous studies, it is aimed to develop a new expandable intramedullary system, providing lengthening in order to remove previous problems and complications and to annihilate leg length discrepancies at present and future without second surgical intervention as far as possibble by lenghtening the intramedullary nail. To this end, a new electromechanically activated intramedullary nail has been designed and generated. The intramedullary nail was designed to perform extremity lengthening electro-mechanically. The 3D design of the system is performed with computer software and the rapid and metal prototype of the system has been produced. The intramedullary nail system is comprised of three main units; Mechanical transmission unit, Electronic unit, Lengthening unit. The nail system is designed to function both mechanically and electronically complying with the requirement. This also provides an advantage that if any one (mechanic or electronic) fails, the lengthening process can continue with the other. Compression tests are applied in order to evaluate the strength of the system. The deformation values of the parts are recorded and stress values of each parts were calculated. The new system needs only 300N loading for mechanical lengthening. When 800N is considered as average human weight, the implant must withstand minumum 2400N load. Considering the safety conditions, we applied 4000N load on the new system. At 4000N, the whole system shows only 1.465 mm deformation which is less than the gap between the two bone parts. Also, when the system is implanted inside the bone, the loads are distributed proportionally between the bone and the implant. So, except for extraordinary conditions, the newly developed system is highly rigid and safe. In each applied method, lots of complications whether general or method-specific are seen. When the methods like Albizzia, ISKD and FITBONE avaliable and widely used today are examined separately, complications specific to these methods can be clearly observed [1–12]. Bliskunov Nail, Albizzia Nail and ISKD [13–18] have mechanical working principles and in these systems, lengthening process is obtained by rotational movement of the extremity. This rotational movement causes complications like pain, dislocation and uncontrolled lengthening [11,13,16,19–21]. In our newly developed system, only axial stimulation is needed for the activation of the mechanism. This is one of the advantages of our system. Both the mechanical unit and the electronical units are designed to be extended 0.1 mm at each activation. This means that the optimal amount of distraction (1mm/day) can be achieved in a controlled way. In other systems, the distraction amount can not be fully controlled and complications seen on other systems [1, 6, 8–10], like distruption of callus due to the excessive distraction and nonunion of the bone can be encountered. The success of the system at practice will be examined with in-vivo animal experiments and according to the results, it will be ready for use on human by performing necessary restorations

Axial forces were measured during limb lengthening in a series of ten patients with varying pathologies in order to assess the mechanical characteristics of the distracted tissues and the levels of axial force to which soft tissues are subjected during leg lengthening. The pattern of force was found to vary according to the underlying pathology. For post-traumatic shortening in adults both the peak and the resting forces rose steadily during lengthening reaching maximum forces of the order of 300 N. Patients with congenitally short limbs developed very high peak forces (in some cases over 1000 N) and also showed large amounts of force relaxation (typically 400 to 500 N). When very high levels of force were recorded, there was a higher complication rate. In particular, there was a high instance of angular deformity. This occurred because the loads encountered resulted in failure of some of the external fixation frames

We developed a rat model of limb lengthening to study the basic mechanism of distraction osteogenesis, using a small monolateral external fixator. In 11-week-old male rats we performed a subperiosteal osteotomy in the midshaft of the femur with distraction at 0.25 mm every 12 hours from seven days after operation. Radiological and histological examinations showed a growth zone of constant thickness in the middle of the lengthened segment, with formation of new bone at its proximal and distal ends. Osteogenic cells were arranged longitudinally along the tension vector showing the origin and the fate of individual cells in a single section. Typical endochondral bone formation was prominent in the early stage of distraction, but intramembraneous bone formation became the predominant mechanism of ossification at later stages. We also showed a third mechanism of ossification, ‘transchondroid bone formation’. Chondroid bone, a tissue intermediate between bone and cartilage, was formed directly by chondrocyte-like cells, with transition from fibrous tissue to bone occurring gradually and consecutively without capillary invasion. In situ hybridisation using digoxigenin-11-UTP-labelled complementary RNAs showed that the chondroid bone cells temporarily expressed type-II collagen mRNA. They did not show the classical morphological characteristics of chondrocytes, but were assumed to be young chondrocytes undergoing further differentiation into bone-forming cells. We found at least three different modes of ossification during bone lengthening by distraction osteogenesis. We believe that this is the first report of such a rat model, and have shown the validity of in situ hybridisation techniques for the study of the cellular and molecular mechanisms involved in distraction osteogenesis

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.

Objectives

In order to ensure safety of the cell-based therapy for bone regeneration, we examined in vivo biodistribution of locally or systemically transplanted osteoblast-like cells generated from bone marrow (BM) derived mononuclear cells.

The aim of our study was to investigate the effect of platelet-rich plasma on the proliferation and differentiation of rat bone-marrow cells and to determine an optimal platelet concentration in plasma for osseous tissue engineering. Rat bone-marrow cells embedded in different concentrations of platelet-rich plasma gel were cultured for six days. Their potential for proliferation and osteogenic differentiation was analysed. Using a rat limb-lengthening model, the cultured rat bone-marrow cells with platelet-rich plasma of variable concentrations were transplanted into the distraction gap and the quality of the regenerate bone was evaluated radiologically.

Cellular proliferation was enhanced in all the platelet-rich plasma groups in a dose-dependent manner. Although no significant differences in the production and mRNA expression of alkaline phosphatase were detected among these groups, mature bone regenerates were more prevalent in the group with the highest concentration of platelets.

Our results indicate that a high platelet concentration in the platelet-rich plasma in combination with osteoblastic cells could accelerate the formation of new bone during limb-lengthening procedures.

We investigated the effect of progesterone on the nerve during lengthening of the limb in rats. The sciatic nerves of rats were elongated by leg lengthening for ten days at 3 mm per day. On alternate days between the day after the operation and nerve dissection, the progesterone-treated group received subcutaneous injections of 1 mg progesterone in sesame oil and the control group received oil only. On the fifth, tenth and 17th day, the sciatic nerves were excised at the midpoint of the femur and the mRNA expression level of myelin protein P0 was analysed by quantitative real time polymerase chain reaction. On day 52 nodal length was examined by electron microscopy, followed by an examination of the compound muscle action potential (C-MAP) amplitude and the motor conduction velocity (MCV) of the tibial nerve on days 17 and 52. The P0 (a major myelin glycoprotein) mRNA expression level in the progesterone-treated group increased by 46.6% and 38.7% on days five and ten, respectively. On day 52, the nodal length in the progesterone-treated group was smaller than that in the control group, and the MCV of the progesterone-treated group had been restored to normal.

Progesterone might accelerate the restoration of demyelination caused by nerve elongation by activating myelin synthesis.

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/cm³ 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.

The feasibility of bone transport with bone substitute and the factors which are essential for a successful bone transport are unknown. We studied six groups of 12 Japanese white rabbits. Groups A to D received cylindrical autologous bone segments and groups E and F hydroxyapatite prostheses. The periosteum was preserved in group A so that its segments had a blood supply, cells, proteins and scaffold. Group B had no blood supply. Group C had proteins and scaffold and group D had only scaffold. Group E received hydroxyapatite loaded with recombinant human bone morphogenetic protein-2 and group F had hydroxyapatite alone.

Distraction osteogenesis occurred in groups A to C and E which had osteo-conductive transport segments loaded with osteo-inductive proteins. We conclude that scaffold and proteins are essential for successful bone transport, and that bone substitute can be used to regenerate bone.

The ability to predict load-bearing capacity during the consolidation phase in distraction osteogenesis by non-invasive means would represent a significant advance in the management of patients undergoing such treatment. Measurements of stiffness have been suggested as a promising tool for this purpose. Although the multidimensional characteristics of bone loading in compression, bending and torsion are apparent, most previous experiments have analysed only the relationship between maximum load-bearing capacity and a single type of stiffness. We have studied how compressive, bending and torsional stiffness are related to the torsional load-bearing capacity of healing callus using a common set of samples of bone regenerate from 26 sheep treated by tibial distraction osteogenesis.

Our findings showed that measurements of torsional, bending and compressive stiffness were all suitable as predictors of the load-bearing capacity of healing callus. Measurements of torsional stiffness performed slightly better than those of compressive and bending stiffness.