Limb lengthening promotes muscle growth

Studies of limb lengthening have demonstrated successful bone formation in the distraction gap. Failure of the muscle units to lengthen leads to many complications that significantly limit the success of this approach; it is, therefore, of paramount importance to characterize the behavior of the muscle during limb lengthening. In this study, tibiae of adult rabbits were lengthened for 10 days at a rate of 1 mm/day. The proliferative ability of the lengthened muscle was characterized using bromodeoxyuridine, a thymidine analogue that is incorporated during cell division, and desmin, a muscle-specific marker. We observed a large number of proliferating cells, specifically in the lengthened muscle, that were co-localized with many desmin-positive cells. The presence of bromodeoxyuridine nuclei inside desminpositive muscle fibers suggests that limb lengthening promotes muscle growth by triggering myoblast proliferation and fusion into the lengthened muscle, Our findings are consistent with those of other studies in the reviewed literature, that also suggest that limb lengthening promotes muscle growth.     

Distraction frequency and the gastrocnemius muscle in tibial lengthening: Studies in rabbits

We compared the effect of various distraction frequencies on the gastrocnemius muscle by evaluating the histological findings, intramuscular enzyme contents, and DNA contents. In 15 rabbits, both tibiae were distracted 1 mm per day. The distraction frequency was 2 steps (0.5 mm/12 hour) by hand on the right side and 120 steps (0.0083 mm/12 minutes) by an auto-distractor on the left. The rabbits were divided into 3 subgroups based on length gain: 10%, 20%, and 30%. Histologically, there were no signs of fibrosis or edema and no differences in the number of necrotic cells, and intramuscular enzyme contents between the 2- and 120-step groups. The DNA content, however, was higher in the 120-step group at 30% lengthening in the middle of the muscle belly, and at 20% and 30% lengthening in the musculotendinous junction. Our findings suggest that an increase in the distraction frequency may promote DNA synthesis in the muscle, thus providing better muscle accommodation during bone lengthening.     

Protective effects of growth hormone on physeal distraction: an experimental study on rabbits

The objective of this study is to evaluate the effects of growth hormone on physeal distraction. We performed physeal distraction of the proximal tibia physis on 32 immature New Zealand white rabbits. The rabbits were randomly allocated into receiving either saline (test 1) or growth hormone (test 2), injected subcutaneously around the physis. Physeal distraction was performed from day 3 to day 28. The animals were sacrificed on day 42. Average net lengthenings achieved as compared with the non-distracted contralateral tibiae were 4+/-2 mm (test 1) and 6+/-2.8 mm (test 2). The difference was of borderline significance (P=0.07). The difference in bone mineral density (BMD) between test 1 and control 1 was -0.019+/-0.021 g/cm2 (P<0.0001). The difference in BMD between test 2 and control 2 was 0.027+/-0.017 g/cm2 (P<0.0001). Histology revealed good trabecular bone formation in all groups. Physeal fractures were present in four rabbits in the saline group (test 1). All rabbits in the growth hormone group achieved lengthening via increased physeal thickness without fracture. New bone formation could be accelerated during physeal distraction by administration of growth hormone. By enhancing physeal cellular activity, growth hormone facilitates lengthening without fracture and may reduce risk of premature physeal closure. Growth hormone may also reduce osteoporosis of the regenerate bone during physeal distraction.     

Changes in canine skeletal muscles during experimental tibial lengthening

In 24 beagles, lengthening of the right tibia was performed by callus distraction after osteotomy and application of a ring fixator. Distraction was started at the fifth postoperative day, with a distraction rate of 0.5 mm twice per day, and ended after 25 days. A control group of six additional dogs underwent tibial osteotomy and external fixation without distraction. Twelve animals with and three animals without leg lengthening were euthanized immediately after the distraction period of 25 days (Group A); the remaining 15 dogs were euthanized after an additional consolidation phase of another 25 days (Group B). From the distracted right leg and from the left control leg the tibialis anterior muscle, extensor digitorum longus muscle, peroneus longus muscle, and gastrocnemius muscle were removed and studied by means of routine histologic, histochemical, and immunohistochemical analyses, and electron microscopic examination. The muscles of the control group showed no differences between the right and left sides. However, in the other 24 dogs of Groups A and B, the authors saw marked alterations affecting only the lengthened muscles but not the muscles of the control limbs. These changes were highly significant and included muscle fiber degeneration and regeneration, target fibers, central cores, minicores, marked endomysial and perimysial fibrosis, and atrophy of Type 1 and Type 2 fibers. In the consolidation period (Group B) fiber type grouping indicated that reinnervation had occurred. In addition, an increase in satellite cells and myoblasts and proliferation of nuclei were observed. The findings of the current study indicate that leg lengthening results not only in muscle fiber degeneration followed by regeneration and reinnervation but also in formation of new muscle tissue.     

A quantitative analysis of the effect of insulin-like growth factor-1 infusion during mandibular distraction osteogenesis in rabbits.

AIM: To quantify, by histomorphometry, the effects of local insulin-like growth factor-1 (IGF-1) during mandibular distraction at various rates. METHODOLOGY: Mature rabbits underwent bilateral mandibular corticotomy and distraction lengthening. Recombinant IGF-1 was administered to two groups of rabbits via osmotic infusion pumps. Distraction regimes were as follows: Group A, 1 mm/day for 15 days; Group B, as for A plus IGF-1; Group C, 3 mm/day for 5 days; Group D, as for C plus IGF-1; and Group E, sham-operated controls. After a 28-day consolidation period, rabbits were sacrificed and bone deposition quantified using DEXA scanning, three-point bending, histological examination and sampled for histomorphometric analysis. RESULTS: DEXA scanning and three-point bending failed to detect any effect of distraction rate or of IGF-1 infusion. Histological and histomorphometric analysis suggested 1 mm/day to be the ideal distraction rate, as this was associated with greater osteoblastic activity and consistent bony union. However, IGF-1 infusion significantly enhanced osteoblastic activity at both distraction rates and resulted in bony union when distraction was performed at 3 mm/day. CONCLUSIONS: Distraction osteogenesis at a rate of 1 mm/day provides greater osteogenic stimulus than 3 mm/day. Exogenous IGF-1 has a positive influence on osteoblastic activity during distraction. Its effect is probably minimised by high levels of endogenous IGF-1.     

Effects of timing of low-intensity pulsed ultrasound on distraction osteogenesis.

We investigated the effects of low-intensity pulsed ultrasound (LIPUS; 30 mW/cm2 spatial and temporal average) on the timing of LIPUS treatment in distraction osteogenesis. Lengthening of the right tibia was performed in 75 male Japanese white rabbits using unilateral fixators (waiting period, 7 days; distraction rate, 1.5 mm/day; distraction period, 7 days). Rabbits were divided into four groups according to the timing of the LIPUS treatment. Control group had no stimulation. Waiting group was treated with a daily 20-min session of LIPUS during a 7-day latency period. Lengthening group was treated during the lengthening period. Maturation group was treated for the first 7 days after completion of distraction. We evaluated the distraction site by radiography and histology every week for 4 weeks. Bone mineral density (BMD) and mechanical strength were tested and microfocus X-ray computed tomography was performed on specimens 2 weeks after completion of distraction. The lengthening group had greater BMD and mechanical strength than the other groups, bone regeneration was enhanced more in the maturation group than in the control or waiting groups. Histologically, endochondral bone formation in the lengthening and the maturation groups occurred earlier than in the control or waiting groups. These results suggest the LIPUS effect is mediated via endochondral pathways. We concluded that LIPUS stimulates bone formation in distraction osteogenesis and is most effective during the lengthening phase.     

Improved comfort in lower limb lengthening with the intramedullary skeletal kinetic distractor

Introduction Limb lengthening by external fixators is associated with many problems such as pain at the pin tracts, muscle transfixation, pin tract infections, reduced joint motion, and prolonged fixation time. The intramedullary skeletal kinetic distractor (ISKD) is a new internal, mechanically activated implant, which distracts by mild rotations of 3°.Material and methods In a prospective clinical study, four patients with an mean age of 29 years (18–36 years) underwent intramedullary lengthening via ISKD. The average lengthening of three femora and one tibia was 31 mm (26–40 mm).Results All patients performed the rotations for the distraction themselves without any significant problems. One patient took mild analgesics during the first days of distraction, whereas three patients did not require any analgesics. The average patient discharge occurred 10 days (8–11 days) postoperatively with no complications during the hospital stay. The planned length of distraction was achieved in all patients with normal alignment and normal joint orientation. Full weight bearing was performed on average after 10 weeks (7–14 weeks). Consolidation was noted 80 days (51–111 days) postoperatively with an average consolidation index of 2.9 days/mm. No complications were observed during the follow-up period of 14 months. The Enneking score was 26.8 points, and according to the classification of Paley all patients had an excellent result.Conclusions From these preliminary results we conclude that the comfort of limb lengthening with the ISKD is increased by the elimination of fixator-associated complications and by the simple distraction mechanism, which is well tolerated by the patients. Further advantages of the ISKD are early full weight bearing and excellent limb function.     

Response of rabbit skeletal muscle to tibial lengthening

Background Experimental and clinical studies have provided knowledge regarding osteogenesis during limb lengthening. However, response of skeletal muscle to limb lengthening is not fully understood, especially as concerns histogenesis. We studied the morphological response of rabbit skeletal muscle to limb lengthening. In this study, we investigated proliferation of satellite cells, responsible for generation of new myonuclei, during limb lengthening. Methods Tibialis anterior muscles of young and adult rabbits were subjected to lengthening at a rate of 0.mm twice per day for 20 days. After lengthening, muscle wet weight was measured to assess skeletal muscle growth, then proliferating cell nuclear antigen was measured. Immunostaining was performed to analyze proliferating cells in the proximal, middle, and distal portions of the muscle belly and the musculotendinous junction. Results Muscle wet weight increased significantly after lengthening both in adult (0.4g) and young (0.1g) rabbits. Satellite cells showed proliferation in response to lengthening. In adult rabbits, satellite cell proliferation increased along the entire lengthened muscle to a similar degree (from 7.1% in the middle portion to 8.6% in the musculotendinous junction). In young rabbits, proliferation was greater in the musculotendinous junction (4.8%) than that in other muscle portions (2.3% in the middle and distal portions, and 2.4% in the proximal portion). In adult rabbits, the rate of increase in satellite cell proliferation was 1780% in the middle portion to 2860% in the musculotendinous junction, whereas the rate was between 210% in the middle portion and 290% in the distal portion in young rabbit. The rate of increase in cell proliferation by lengthening was higher in adult muscle than that in young muscles as well as satellite cell proliferation. Conclusion These findings indicate that limb lengthening promotes muscle growth in both young and adult rabbits.     

Limb lengthening by distraction of the epiphyseal plate. A comparison of two techniques in the rabbit

We have compared, in rabbits, two techniques of limb lengthening by distraction of the epiphyseal plate using a unilateral external fixation frame. In all cases, 14 mm of symmetrical lengthening without deviation was achieved. With rapid distraction at rates of 1 mm per day (distractional epiphyseolysis) separation of the epiphysis from the metaphysis occurred by day 7, and by day 70 almost complete ossification of the cartilage and the elongated segment was evident. In contrast, slow distraction at 0.25 mm every 12 hours (chondrodiatasis) produced hyperplasia of growth cartilage without any evidence of detachment at 28 days, the end of the distraction period. By day 70 the epiphyseal plate had returned to normal thickness with normal cellular morphology, while the lengthened segment was occupied by ossified tissue. The significance of these findings is discussed.     

Management of peripheral nerve defects: external fixator-assisted primary neurorrhaphy

BACKGROUND: Controlled joint extension followed by gradual distraction with use of an external fixator may facilitate primary repair of peripheral nerve defects by permitting end-to-end repair without tension. The hypothesis of the present study was that gradual lengthening of nerve repairs with use of incremental distraction would provide superior results compared with grafting or repair under tension. METHODS: A median nerve segment measuring four times the diameter of the nerve was resected in thirty-six rabbits to create a 7-mm gap in the nerve. Neurorrhaphy was performed with use of one of three techniques. In Group 1 (cable graft), a tension-free medial antebrachial cutaneous graft was placed to allow full range of motion of the elbow postoperatively. In Group 2 (end-to-end repair without distraction), the elbow was externally fixed in hyperflexion and the nerve was repaired end-to-end. At fourteen days, the fixator was removed and unprotected elbow motion was permitted. In Group 3 (end-to-end repair with gradual distraction), the elbow was externally fixed in hyperflexion and primary neurorrhaphy was performed. At fourteen days, the elbow was extended 10 degrees every other day with use of the articulated external fixator until full extension was achieved. Median nerve amplitude, latency, and nerve-conduction velocity; flexor digitorum superficialis single-twitch force generation and maximum tetanic force generation; muscle mass; and elbow range of motion were measured at three or six months. In addition, histologic analysis of the median nerve distal to the repair site and the morphometry of the neuromuscular junction in the flexor digitorum superficialis were performed at six months. RESULTS: All rabbits regained full active and passive range of motion. At three months, the nerve-conduction velocities in Groups 2 and 3 were significantly greater than that in Group 1. At six months, the nerve-conduction velocities and amplitudes in Group 3 were significantly greater than those in Groups 1 and 2. At six months, the tetanic force in Group 3 was significantly greater than those in Groups 1 and 2. There were no significant differences in muscle mass among the groups. There were no significant differences in histological findings among the three groups, although there was a trend toward larger fiber size in Group 3 as compared with the other two groups. The neuromuscular junctions in Group 3 had a significantly larger surface area than did those in Group 1 (p = 0.002) and Group 2 (p = 0.034). CONCLUSION: The use of an articulated external fixator and controlled gradual distraction appears to facilitate the treatment of peripheral nerve defects.     

Biomechanical investigation of distraction forces appearing in the course of femoral lengthening in rabbits: radiological and histological study]

This study was conducted in order to determine the values of forces necessary to stretch bony fragments during tibia lengthening in rabbits. The aim of this study was to determine the conditions which lead to complications of the lengthening process related to the rate of distraction. The experiment was conducted on 16 rabbits of New Zealand breed. The construction of the apparatus eliminated tension resulting from the so-called "bending moment". In all rabbits distraction was began on the 5th day after fixing the apparatus. The standard rate of lengthening was 2 x 0.25 mm per day. In 8 rabbits the rate of distraction was regulated. The distraction forces were measured and electronically recorded during the distraction procedure, during the animal's movement and resting position at strictly monitored intervals. Radiological examination of the lengthened tibia was performed once a week. Histological examination was performed in three rabbits after completion of the experiment. We made 328 measurements of the involved distractive forces, collecting a total of 223 MB of data. Graphical representation of the lengthening force and it's performance turned out to be similar for various experimental animals and it's course was typical for every stage of the lengthening process. At the time of distraction of the apparatus the measured force increased on average by 0.87 N (minimum 0.61, maximum 1.1N). Abnormal rates of distraction resulted in a break of the callus continuity in 3 rabbits. Radiological and histological examinations were used to assess to confirm certain observations concerning the technique and rate of distraction.     

Effect of nerve growth factor and Schwann cells on axon regeneration of distracted inferior alveolar nerve following mandibular lengthening

To study the effect of nerve growth factor(NGF) and Schwann cells on axon regeneration of theinferior alveolar nerve following mandibular lengtheningwith distraction osteogenesis.     

The role of aspirin and dipyridamole on vascular DNA synthesis and intimal hyperplasia following deendothelialization

Platelets are implicated both in acute thrombotic events and, through platelet-derived growth factor, in the development of intimal hyperplasia. We have investigated, in vivo, the influence of aspirin and dipyridamole on vascular smooth muscle cell proliferation and DNA synthesis following balloon catheter injury. Fifty-eight male, New Zealand white rabbits were divided equally into two groups; the test group was fed aspirin (14 mg/kg/day) and dipyridamole (9 mg/kg/day) from 2 days prior to surgery until sacrifice at 1, 2, 3, 4, 7, 14, or 28 days after injury. All animals were sacrificed 1 h after injection of [3H]thymidine and the smooth muscle cell DNA specific activity and total kinetic activity were determined. Intimal hyperplasia was measured by light microscopy and intimal nuclear proliferation was determined by counting nuclei per millimeter of internal elastic lamina. Nuclear proliferation was maximal at 14 days (25 +/- 1.2) but intimal hyperplasia was still increasing at 28 days. DNA specific activity after 24 hr (test: 4 +/- 2 dpm/micrograms DNA; control: 3.3 +/- 3 dpm/micrograms DNA) was similar to basal levels in uninjured rabbits. DNA synthesis peaked in both groups between the second and third day (test: 177 +/- 27 dpm/micrograms DNA; control: 185 +/- 39 dpm/micrograms DNA) and then declined slowly toward baseline values. There was no significant difference between treated and normal rabbits in either [3H]thymidine incorporation, nuclear proliferation, or development of intimal hyperplasia despite 90% inhibition of platelet aggregation and a significant reduction (78%) in [14C]serotonin release following collagen challenge (6 micrograms/ml).(ABSTRACT TRUNCATED AT 250 WORDS)     

Bone consolidation is enhanced by rhBMP-2 in a rabbit model of distraction osteogenesis.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a differentiation factor which has been shown to induce bone formation and heal bony defects in a variety of animal models. A possible application of rhBMP-2 is to accelerate bone regeneration during distraction osteogenesis. which clinically is a long procedure, often involving significant complications. In this study we tested the ability of rhBMP-2 to accelerate the consolidation phase of distraction osteogenesis in a rabbit model of leg lengthening. Tibiae were lengthened 2 cm over a period of ten days. rhBMP-2 was administered at the end of the lengthening phase. Two modes of rhBMP-2 application were tested: surgical implantation of rhBMP-2/ACS (absorbable collagen sponge) into the regenerate (50 microl of 1.5 mg/ml rhBMP-2, total dose = 75 microg rhBMP-2), and percutaneous injection of rhBMP-2/buffer (0.1 ml of 0.75 mg/ml rhBMP-2. total dose = 75 microg rhBMP-2) into three sites within the regenerate. Also, there were three groups of control animals: (1) no surgical intervention, (2) surgical implantation of buffer/ACS and (3) percutaneous injection of buffer. Rabbits were sacrificed at 5, 14 and 28 days after the interventions. Radiographic evaluation indicated a significant increase in bony union of the distraction regenerate in the rhBMP-2 treated groups compared with the untreated groups at 5 and 14 days. At 28 days, formation of a cortex and reestablishment of the medullary canal was evident only in the rhBMP-2 treated groups. The bone mineral content (BMC) of the regenerate was significantly higher in the rhBMP-2 treated groups at 5 and 14 days. However, at 28 days, BMC of the regenerate was similar in all groups. The average volumetric density of the regenerate was significantly higher in the rhBMP-2 injection group at day 14. In Summary, both injection of rhBMP-2/buffer and implantation of rhBMP-2/ACS enhanced the consolidation stage of distraction osteogenesis in this rabbit model.     

Membranous bone lengthening: a serial histological study.

Bone lengthening using the process of corticotomy and gradual distraction of callus is applicable to the membranous bone of the canine mandible. In this study the precursors to bone formation, in the area between the distracted bone edges, are analyzed in an attempt to determine the mechanism of bone formation. Ten mongrel dogs 5 months of age were studied. A unilateral, periosteal-preserving angular corticotomy was performed, and an external bone-lengthening device was fixed to the mandible. After 10 days of external fixation, the mandible was lengthened 1 ml per day for 20 days and then held in external fixation for 8 weeks. The dogs were killed for histological and microradiographic study at 10 and 20 days of distraction, and at 14, 28, and 56 days after the completion of distraction. It was observed that the gap between the distracted bone edges is first occupied by fibrous tissue. As distraction proceeds, the fibrous tissue becomes longitudinally oriented in the direction of distraction. Early bone formation advances along the fibrous tissue, starting from the cut bone ends. Eventually the area is converted to mature cortical bone. Bone is formed predominantly by intramembranous ossification. This mechanism is similar to that of bone formation during long bone lengthening.     

Distraction osteogenesis for the treatment of post traumatic complications using a conventional external fixator. A novel technique

PURPOSE: To evaluate the clinical results of post traumatic complications treated by the author's own technique using an AO/ASIF conventional external fixator (without special distraction device). MATERIALS AND METHODS: There were 70 patients (77 limbs) with an average of 26.8 years (range, 4-54). There were 33 femurs, 43 tibias and one ulna. The following post traumatic complications were treated: 14 limb shortening, 20 nonunion, 28 malunion 14 infected open fractures with bone loss and 1 chronic osteomyelitis. Linear lengthening was performed in 29 limbs, acute de-rotation and subsequent lengthening in two limbs, gradual angular correction in six limbs, combined gradual angular correction and subsequent lengthening in 10 limbs, combined acute angular correction and subsequent lengthening in eight limbs and 22 limbs with bony defects were treated with the technique so-called "bone transportation". All of the limbs were treated with an AO/ASIF conventional external fixator, using the author's own technique with distraction rate of 1 mm in one step on alternate day (1 mm/48 h). RESULTS: A new bone formation in the distraction gap was achieved in 73 of the 77 limbs. Four cases without consolidation were successfully treated with an iliac bone graft combined with plating or reapplication of the external fixator. Average new bone formation was 5.6 cm (range, 1-17 cm). The average follow-up period was 10.8 months (range, 1-71 months) after removal of the fixator. The average healing time was 244.7 days (range, 60-836 days) and the healing index was 50 days/cm (range, 17-100 days). In the group with associated angular deformity the mean correction was 18.5 degrees (range, 10-40). CONCLUSIONS: The author's technique of distraction osteogenesis, using a conventional external fixator combined with a distraction rate of 1 mm/48 h (1 mm/step) adequately treated the post traumatic complications. No extra equipment was needed other than readily available AO/ASIF fixation systems. The described technique, using an AO/ASIF fixator as a lengthening apparatus was simple and cost-effective.     

Metacarpal lengthening by distraction histiogenesis in adults

Background:

Metacarpal lengthening in the hand is a new application for distraction neo-histiogenesis. Metacarpal lengthening with distraction helps in improvement in pinch function. Thumb lengthening is technically easy in comparison to other metacarpals. We present the operative treatment and post-operative outcome in nine patients with amputations and congenital anomalies.

Materials and Methods:

Nine patients underwent distraction osteogenesis for the treatment of amputations of the hand and other congenital anomalies. The dominant right hand was operated in eight cases and the left hand in one case. There were six males and three females. Improvement of function was always the aim of surgery. Age range was between 18 and 23 years. Thumb lengthening was performed in five patients and that of the index finger in four patients. Distraction started on the fifth post-operative day at the rate of 0.25 mm/day. Sensory function and bone consolidation was assessed before fixator removal.

Results:

The mean duration of distraction was 51 days (range, 42–60 days) and the distractor was removed at a mean of 150 days (range, 140 and 160 days) and the bones were lengthened by a mean of 24 mm (range, 20–28 mm) There was improvement of function in all cases.

Conclusion:

The metacarpal lengthening by distraction histiogenesis in congenital and traumatic amputations is safe and simple method to improve pinch function of hand.     

Effect of tibial lengthening on the gastrocnemius muscle: A histopathologic and morphometric study in rabbits

We observed the changes of the gastrocnemius muscle in relation to the percentage of lengthening of the rabbit's tibia by callotasis. 75 rabbits were separated into 3 lengthening groups, 10, 20, and 30 percent lengthening, respectively. Histopathologic observations, based on the fiber size variation, intemalization of the nuclei, degeneration, regeneration, and endo-mysial fibrosis of muscle fibers, revealed that substantial changes occurred in the latter groups. Histo-morphometrically, the decrease in the mean size of Types I and II muscle fibers was observed in all lengthening groups, but there was no significant change in the proportion of the muscle fiber types in any of the lengthening groups.     

Verlängerung der unteren Extremität mit dem Intramedullary Skeletal Kinetic Distractor (ISKD)

OBJECTIVE: Callus distraction of the femur or tibia with an intramedullary distractor, which lengthens mechanically through alternating rotations of at least 3 degrees. INDICATIONS: Femoral or tibial shortening between 20 and 80 mm. Angular and rotational deformities can be corrected at the osteotomy site. CONTRAINDICATIONS: Open epiphyses. Small medullary canal (after intramedullary reaming femoral diameter < 14.5 mm, tibial diameter < 12.5 mm). Severe deformities. Insufficient compliance. Osteitis. Soft-tissue infections. SURGICAL TECHNIQUE: Supine position. Femoral shaft osteotomy at the proximal or middle third by multiple drill holes completed with a chisel. For lengthening of the tibia, osteotomy with a Gigli saw is preferred. Control of the rotation by two parallel 3.0-mm Kirschner wires. Correction of angular or rotational deformities. Via stab incision reaming of the medullary canal with a flexible reamer. The femur is overreamed 2.0 mm and the tibia 1.5 mm above the desired implant diameter. Insertion of the Intramedullary Skeletal Kinetic Distractor (ISKD) into the medullary canal and distal locking in freehand technique. Control of the rotation and of the osteotomy gap. Proximal locking with an aiming device. For femoral lengthening 3 days and for tibial lengthening 5 days postoperatively the distraction is begun by increasing mobilization with partial weight bearing, to achieve daily distraction of 1 mm. In case of insufficient distraction, additional rotations are performed by the patient while checking the external monitor that displays the daily and total distraction length. RESULTS: Intramedullary lengthening with the ISKD was performed in four patients having an average age of 29 years (18-36 years). Two femoral shortenings were combined with complex rotational and angular deformities. The average lengthening of three femora and one tibia was 31 mm (26-40 mm). The average intraoperative blood loss was 230 ml (110-320 ml), the mean surgical time 108 min (90-145 min). The average daily distraction amounted to 1.2 mm (0.9-1.8 mm). Full weight bearing was permitted after 10 weeks (7-14 weeks), return to regular work after 11 weeks (7-16 weeks). At follow-up examination of an average of 2.3 years postoperatively the knee range of motion was full. Consolidation was noted 80 days (51-111 days) postoperatively with an average consolidation index of 2.9 days/mm (1.8-4.1 days/mm). No complications were observed. According to the Paley Score all patients had an excellent outcome.     

Femur lengthening with a telescopic intramedullary nail ISKD--method presentation and early clinical results

INTRODUCTION: Limb discrepancy over 4 cm is an indication for limb lengthening. Surgical techniques rely on osteotomy, external stabilisation and gradual distraction. The ISKD (Intramedullary Skeletal Kinetic Distractor) nail allows distraction osteogenesis and no external fixator is required. AIM OF PAPER: Aims of paper are: presentation of limb elongation method with the ISKD device, and presentation of early own results. MATERIAL AND METHODS: Material consists of 5 patients, age 14-16 years, 3 boys and 2 girls, who underwent femur lengthening with the ISKD nail between 2005 and 2007. We evaluated: initial shortening, surgical procedure, complications, amount of lengthening, lengthening rate, distraction index, time of treatment and mobility of adjacent joints. RESULTS: Initial shortening was 4-11 cm. No surgical complications were observed, mean time of surgery was 145 minutes, mean blood loss--200 ml. In three patients difficulties with initial distraction required manipulations under general anaesthesia. Distraction was complicated in 3 cases--in two patients premature consolidation was noted; in one case the distraction rate was too high. Mean lengthening rate in the study group was 0.7 mm/day (0.6-0.7 mm/day). Mean distraction index was 41.7 days/cm (26.2-55 days/cm). Full weight bearing was allowed after mean 234 days (210-275 days). Transient decrease of adjacent joint mobility was observed. CONCLUSION: The fully implantable, telescopic ISKD eliminates the need of external fixation and associated complications. Early results of limb lengthening with ISKD are encouraging. Careful patient selection and preoperative planning is required. Further studies and longer follow-up periods are needed.