J Orthop Res. 2006 Jan;24(1):2-10.
Effect of pulsed electromagnetic fields on maturation of regenerate bone in a rabbit limb lengthening model.
Taylor KF, Inoue N, Rafiee B, Tis JE, McHale KA, Chao EY.
Department of Orthopaedics and Rehabilitation, Walter Reed Army Medical Center, 6900 Georgia Avenue NW, Washington, DC 20307-5001, USA.
To study the effect of applying pulsed electromagnetic fields (PEMF) during the consolidation phase of limb lengthening, a mid-tibial osteotomy was performed in 18 adult New Zealand White rabbits and an external fixator was applied anteromedially. Animals were randomly assigned to treatment and control groups. After a 7-day latency period, the tibiae were distracted 0.5 mm every 12 h for 10 days. The treatment group received a 20-day course of PEMF for 60 min daily, coinciding with initiation of the consolidation phase. The control group received sham PEMF. Radiographs were performed weekly after distraction. Animals were euthanized 3 weeks after the end of distraction. Radiographic analysis revealed no significant difference in regenerate callus area between treatment and control tibiae immediately after distraction, at 1 week, 2 weeks, or 3 weeks after distraction ( p = 0.71, 0.22, 0.44, and 0.50, respectively). There was also no significant difference in percent callus mineralization ( p = 0.96, 0.69, 0.99, and 0.99, respectively). There was no significant difference between groups with respect to structural stiffness ( p = 0.80) or maximal torque to failure ( p = 0.62). However, there was a significant positive difference in mineral apposition rate between groups during the interval 1-2 weeks post-distraction ( p < 0.05). This difference was no longer evident by the interval 2-3 weeks post-distraction. While PEMF applied during the consolidation phase of limb lengthening did not appear to have a positive effect on bone regenerate, it increased osteoblastic activity in the cortical bone adjacent to the distraction site. Since the same PEMF signal was reported to be beneficial in the rabbit distraction osteogenesis when applied during distraction phase and consolidation phase, application of PEMF in the early phase may be more effective. Further work is necessary to determine optimal timing of the PEMF stimulation during distraction osteogenesis.
Acta Orthop Belg. 2005 Oct;71(5):571-6.
Pulsed electromagnetic stimulation of regenerate bone in lengthening procedures.
Luna Gonzalez F, Lopez Arévalo R, Meschian Coretti S, Urbano Labajos V, Delgado Rufino B.
Servicio de Traumatología, Hospital Clínico Universitario “Virgen de la Victoria”, Málaga, Spain. email@example.com
Distraction osteogenesis for limb lengthening represents the treatment of choice in patients with small stature or limb length discrepancies. Bone lengthening and callus formation requires a long therapy. Pulsed electromagnetic fields (PEMF) are normally used to enhance osteogenesis in patients with non-unions. In this study we investigated whether pulsed electromagnetic fields could be used effectively to encourage callus formation and maturation during limb lengthening procedures. Thirty patients underwent bilateral bone lengthening of the humerus, femur or tibia. At day 10 after surgery, PEMF stimulation was started on one side, for 8 hours/day. Stimulated distraction sites exhibited earlier callus formation and progression, and a higher callus density compared to non-stimulated sites. External fixation could be removed on average one month earlier in PEMF stimulated bones. Our results show that the use of pulsed electromagnetic fields stimulation during limb lengthening allows shortening the time of use of the external fixation.
J Pediatr Orthop. 2003 Jul-Aug;23(4):478-83.
Effects of pulsed electromagnetic field stimulation on distraction osteogenesis in the rabbit tibial leg lengthening model.
Fredericks DC, Piehl DJ, Baker JT, Abbott J, Nepola JV.
Bone Healing Research Laboratory, Department of Orthopaedic Surgery, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA. firstname.lastname@example.org
The purpose of this study was to determine whether exposure to pulsed electromagnetic field (PEMF) would shorten the healing time of regenerate bone in a rabbit tibial distraction model. Beginning 1 day after surgery, mid-shaft tibial osteotomies, stabilized with external fixators, were distracted 0.25 mm twice daily for 21 days and received either no exposure (sham control) or 1 hour per day exposure to low-amplitude, low-frequency PEMF. Tibiae were tested for torsional strength after 9, 16, and 23 days post-distraction. PEMF-treated tibiae were significantly stronger than shams at all three time points. By 16 days post-distraction, the PEMF group had achieved biomechanical strength essentially equivalent to intact bone. Shams did not achieve normal biomechanical strength even after 23 days post-distraction. In this tibial distraction model, short daily PEMF exposures accelerated consolidation of regenerate bone. Clinical usefulness awaits testing.
|Bone. 1996 Jun;18(6):505-9.|
Effect of pulsed electromagnetic fields on bone formation and bone loss during limb lengthening.
Eyres KS, Saleh M, Kanis JA.
WHO Collaborating Centre for Metabolic Bone Disease, University of Sheffield Medical School, UK.
We examined the effect of pulsed electromagnetic fields (PEMFs) on bone formation and disuse osteoporosis sustained during limb lengthening in a double-blind study. Seven males (mean age 13 years, range 11-19 years) and six females (mean age 12 years, range 9-19 years) were randomly allocated to receive either an active or an inactive PEMF coil. Limb lengthening was performed by the Villarubbias technique using either a unilateral or circular frame system. Sequential bone density measurements were made using dual energy X-ray absorptiometry and compared to traditional radiographs. Ten segments (eight tibial and two femoral) in seven patients were lengthened under the influence of active coils and eight segments (six tibial and two femoral) in six patients using inactive coils. There was no difference in the rate nor the amount of new bone formed at the site of distraction between the two groups. Bone loss in the segments of bone distal to the lengthening sites was observed in both groups but was significantly more marked using inactive coils (BMD reduced by 23% +/- SEM 3% and 33% +/- 4% control values after one and two months, respectively; p < 0.0001) than using active coils (BMD reduced by 10% +/- 2% at 2 months). These differences were greater at 12 months after surgery (reduced by 54% +/- 5% and 13% +/- 4%, respectively; p < 0.0001). Stimulation with pulsed electromagnetic fields has no effect on the regenerate bone, but does prevent bone loss adjacent to the distraction gap.
J Am Coll Surg. 1996 May;182(5):394-402.
A review of 240 patients undergoing distraction osteogenesis for congenital post-traumatic or postinfective lower limb length discrepancy.
Maffulli N, Lombari C, Matarazzo L, Nele U, Pagnotta G, Fixsen JA.
Department of Orthopedic Surgery, University of Aberdeen Medical School, Scotland.
BACKGROUND: We reviewed 281 lower limb lengthenings in 240 patients treated at three centers for congenital, post-traumatic, or postinfective limb length discrepancy (LLD) in the period 1984 to 1992.
STUDY DESIGN: A retrospective review was done of hospital charts and radiographs of patients who had completed lengthening at least 12 months prior to the beginning of the study. The variables studied included patients’ age at operation, the bone segment lengthened, whether a corticotomy or an osteotomy had been done, the amount of lengthening planned and achieved, the level(s) of corticotomy or osteotomy, the external fixator used, and the difficulties encountered.
RESULTS: Limb length discrepancy was reduced within 2 cm (1.6 percent or lower) of the normal contralateral leg in 249 (89 percent) lengthenings in 208 patients. The average time spent with the fixator in situ was 186.4 days (range, 94 to 617 days), with an average healing index of 35.3 days per cm (range, 26 to 43 days per cm). Femoral osteotomies or corticotomies healed faster than tibial osteotomies or corticotomies. The healing index in post-traumatic and postinfective LLD was significantly lower than in congenital conditions. The younger patients showed a significantly decreased time to bone healing and fewer complications.
CONCLUSIONS: A significantly greater number of difficulties were found in patients whose lengthening exceeded 18 percent of the original length of bone. Bifocal lengthenings healed significantly faster than single level ones. The three external fixators used were equally effective for lengthenings of less than 20 percent. The Ilizarov and the Monticelli-Spinelli circular fixators were associated with a significantly decreased number of complications when lengthenings above 20 percent were performed.
|Chir Narzadow Ruchu Ortop Pol. 1992;57(1-3):247-9.|
Use of magnetotherapy for treatment of bone malunion in limb lengthening. Preliminary report.
[Article in Polish]
Rajewski F, Marciniak W.
Kliniki Ortopedii Dzieciecej Instytutu Ortopedii i Rehabilitacji AM im. K. Marcinkowskiego w Poznaniu.
Two children with bone malunion after lengthening of congenitally shortened lower leg have been presented. The crus has been elongation 8 cm by Ilizarov method in 9 years old boy and 5 cm elongation of the tibia has been achieved with the use of Bastiani method in 8 years old girl. In both cases malunion has occurred. The radiographs revealed pseudoarthrosis (the girl, 6 month after operation) and centrally located bony defect (the boy, 2 months postoperatively). In both cases pulse sinusoidal magnetic field was applied successfully with cortical bone and marrow cavity restored in 2 months.
|Clin Orthop Relat Res. 1991 May;(266):304-12.|
Bone growth and remodeling after distraction epiphysiolysis of the proximal tibia of the rabbit. Effect of electromagnetic stimulation.
van Roermund PM, ter Haar Romeny BM, Hoekstra A, Schoonderwoert GJ, Brandt CJ, van der Steen SP, Roelofs JM, Scholten F, Visser WJ, Renooij W.
Department of Orthopedic Surgery, Utrecht University Hospital, The Netherlands.
The effect of pulsed electromagnetic stimulation on bone formation was tested in a lower-limb-lengthening model in the rabbit. Limb lengthening was performed by distraction epiphysiolysis. A specially designed external distraction device allowed 10 mm of lengthening of the tibia. Coils to generate a pulsed electromagnetic field were clipped onto the distractor. Stimulation started after a distraction period of three weeks and was continuous for 18 weeks. A control group received the same treatment without stimulation. Bone formation in the elongated zone was evaluated by computed tomography, scintigraphy, and histology. Bone healing involved accretion of callus followed by a process of remodeling, resulting in the formation of a solid cortex. The formation of a diaphysislike structure at the original site of the metaphysis progressed from the distal end of the elongated zone upward. Electromagnetic stimulation had no effect on the rate or extent of bone formation and remodeling.