Treatment of Noninfected Nonunions: Normotrophic Nonunions
GABRIELLATUVO, REDENTOMORA, GIOVANNIBATTISTAGALLI
Introduction
In normotrophic nonunions (the intermediate category between hyper- trophic and atrophic nonunions), vascularization at the nonunion site is poor but exists, and on the bone scan detection of the tracer is poor.
The biological activity of the connective tissue in the interfragmentary gap is low but not absent. Therefore, the aim of the treatment is to increase this capability and enhance the osteogenic properties of the tissue.
Operative Technique (Monofocal Compression-Distraction Osteosynthesis)
The monofocal compression-distraction osteosynthesis technique consists of alternating phases of compression and distraction of the nonunion site, gen- erally performed with a cycle of gradual compression of 4–5 mm at the rate of 1 mm per day in only one session, followed by a gradual distraction of 4–5 mm and a rest period of 4–5 days (Figs. 1–3).
The cycle is then repeated two or three times. These “gymnastics” revive, in most cases, the osteogenic capacity at the nonunion site and consolidation is achieved [1]. In patients in whom a dysmetria or an axial deviation are present, the treatment is appropriately modified to correct the deformity.
Materials and Methods
In the period 1894–2002, 74 normotrophic nonunions were treated. The min- imum follow-up time was 2 years. Of the patients, 51 were men and 23 women. Age ranged from 30 to 72 years (average 38 years). The affected bone was the humerus in 10 cases, the femur in 18, and the tibia in 46. An open frac- ture was present in the history of 19 patients.
174 G. Tuvo, R. Mora, G.B. Galli
The period between the trauma and the treatment with compression-dis- traction methods was 6–50 months. Previously, 31 patients had received conser- vative treatment and 43 patients surgical treatment. A limb shortening was evi- dent in nine cases, an axial deviation in six. Patients were treated with the mono- focal compression-distraction osteosynthesis technique, correcting both dysme- tria and axial deviation when these deformities coexisted. For the treatment the Ilizarov system was used in 66 cases and the Kalnberz system in eight cases.
Fig. 1a, b. X-rays of a non- union of the left leg in a 65- year-old man
Fig. 2a, b. Same case as in Fig. 1. Treatment with mono- focal compression-distrac- tion osteosynthesis by means of a Kalnberz “Rigid Sim- plex” external fixator
a b
a b
Treatment of Noninfected Nonunions: Normotrophic Nonunions 175
Results
The average time of treatment was 4 months (2.5 to 6 at most). No intraoper- ative complications developed. Among the minor postoperative complica- tions, there were 27 cases of superficial infection at the entry site of wires or screws (treated with local medication and antibiotic therapy) and two cases of wire breaking (substituted in one case). No vascular or nervous complica- tions were observed.
Consolidation was obtained in all but four cases, which were then treated with autologous bone grafting. No residual deformity was observed. The articular function (reduced during the treatment of femoral nonunions) appeared to be normal after fixator removal and kinesitherapy.
Discussion
Alternating compression-distraction stimulation of the nonunion site has proven to be very effective in the management of normotrophic nonunions, where biological activity of the connective tissue in the gap is poor [2–4].
The favorable effect on bone formation can be explained by Leung’s hypothesis [4], which is based on experimental data on weight bearing during distraction osteogenesis. According to this hypothesis, it is likely that, in nor- motrophic nonunions, the tensile stress on the biologic tissue induced by dis- traction initiates osteogenesis and also creates microstrain across the dis- traction site. The compression across the distraction site induces changes in Fig.3a,b.Same case as in Fig. 1. Heal- ing of the nonunion after 3 months
a b
176 G. Tuvo, R. Mora, G.B. Galli
microstrain and causes an additive effect with enhancement of osteogenesis and mineralization, provided that, according to Kenwright et al. [5], the change in strain is the most effective kind of stimulation for bone formation.
References
1. Ilizarov GA, Green SA (1992) Transosseous osteosynthesis. Springer, Berlin Heidelberg New York
2. Paley D (1990) Treatment of tibial nonunions and bone loss with the Ilizarov tech- nique. AAOS Inst Course Lect 39:185–197
3. Mora R (2000) Tecniche di compressione-distrazione. Amplimedical, Milano 4. Leung K, Cheung W,Yeung H et al (2004) Effect of weightbearing on bone formation
during distraction osteogenesis. Clin Orthop Relat Res 419:251–257
5. Kenwright J, Richardson JB, Cunningham JL et al (1991) Axial movement and tibial fractures. A controlled randomised trial of treatment. J Bone Joint Surg Br 73:654–659
