Treatment of Noninfected Nonunions: Atrophic Nonunions
REDENTOMORA, LUISELLAPEDROTTI, BARBARABERTANI, MILENAMICELI
Introduction
In atrophic nonunions vascularization of the bone ends is almost absent, and the scintigraphic images do not detect anything. In this kind of nonunion the interfragmentary gap is filled with loose connective tissue, unable to express any biological activity: thus, further stimulation with gradual distraction cannot lead to bone regeneration.
Operative Technique (Biofocal Compression-Distraction Osteosynthesis)
The operative technique with compression-distraction systems (bifocal com- pression-distraction osteosynthesis) acts at two levels [1]: at the nonunion site (where a reshaping of the hypotrophic-hypovascularized bone ends is performed) and at the proximal or distal metaphysis of the long bone (where a corticotomy is performed in order to allow a gradual distraction with “bone transport” or “internal lengthening” at the rate of 1 mm per day in only one daily session).
The bone fragment, which is gradually transported, comes into contact with the other bone end at the resection site; then interfragmentary com- pression is performed at the docking site to achieve consolidation (Figs. 1–7).
The shape of the bone ends must be considered. In most cases the seg- mental excision technique is the best choice in order to achieve a wide area of bone contact on both bone ends. In particular cases, bone contact may be improved by modifying the bone ends: with the invagination technique one of the fragments is fitted into the other; with the reshaping technique the two fragments are surgically molded in complementary shapes [2, 3].
Bone can be transported using transversely oriented, obliquely oriented, or longitudinally oriented transport wires. The first technique is the simplest, but actually the most troublesome for the patient, so it is rarely used. We pre-
Fig. 1a, b.X-rays of an atrophic nonunion of the distal third of the right tibia in a 34-year- old man
a b
Fig. 2a, b.Same case as in Fig. 1. Treatment with reshaping of the bone ends, proximal metaphyseal corticotomy, bifocal compression-distraction osteosynthesis performed with an Ilizarov apparatus
a b
Treatment of Noninfected Nonunions: Atrophic Nonunions 179
fer the oblique wire transport system, which shows the best compromise between functionality and tolerability. The longitudinal wire transport sys- tem proposed by Umiarov [4] is described in Chapter 16 (“Treatment of Infected Nonunions”): the bulking and the discomfort of this system (in the early stages of treatment) are balanced by the accuracy of the transported fragment movement.
Distraction performed at two sites within the bone can help shorten total treatment time. Three forms of this kind of treatment can be determined [3]:
1. “Unilateral” bone transport: the kind of transport described above.
2. “Contralateral” bone transport: a corticotomy is performed both proxi- mally and distally and two bone segments are transported centripetally.
3. “Ipsilateral” bone transport: the segment is divided in two (or more) parts and each part is transported towards the next one (Figs. 8–10).
Delayed consolidation or lack of consolidation of the nonunion site can be observed. Opening the nonunion site and once again reshaping the bone ends or bone grafting at the site of the delayed consolidation is sometimes neces- sary [2, 3].
Fig. 3a, b. Same case as in Fig. 1. Bone transport with the oblique wire system. X-rays performed 2 months after transport has begun
a b
Fig. 4a-d.Same case as in Fig. 1. At the end of the treatment (6 months), proximal bone is well regenerating (a, b) and the docking site is consolidated (c, d)
a b
c d
Treatment of Noninfected Nonunions: Atrophic Nonunions 181
Materials and Methods
Between 1984 and 2002, 61 noninfected atrophic nonunions were treated with a follow-up of at least 24 months. There were 38 men and 23 women, with an average age of 33 years (range 26–45 years).
In all cases the nonunion site was the tibia. In 43 cases there was an open fracture at the moment of the trauma. The average time from the injury to the treatment with compression-distraction systems was 6 months (range 4–12).
Almost all patients had previously received surgical treatment (n=52).
Leg shortening was evident in 25 patients; axial deviation was observed in 19 patients. The surgical treatment used was bifocal or multifocal compres- sion-distraction osteosynthesis technique, reshaping bone ends and correct- ing dysmetria and angular deformity when necessary. In all patients the Ilizarov system was employed.
Fig. 5a, b.X-rays of an atrophic nonunion of the proximal third of the left tibia in a 57- year-old woman
a b
Fig. 6a-d.Same case as in Fig. 5. a, b Treatment with reshaping of the bone ends, distal metaphyseal corticotomy, bifocal compression-distraction osteosynthesis by means of an Ilizarov apparatus. c, d Bone transport with the oblique wire system. X-rays perfor- med 3 months after transport has begun
a b
c d
Treatment of Noninfected Nonunions: Atrophic Nonunions 183
Fig. 7a, b.Same case as in Fig 5. X-rays at the end of the treatment (7 months): distal bone is well regenerated and the docking site is consolidated
a b
Fig. 8a, b. X-rays of an atrophic nonunion of the left tibia in a 24-year-old
a b man
Fig. 9a-e.Same case as in Fig. 8. a-c Treatment with wide resection (12 cm) of the atro- phic ends and “double level” bone transport. d, e Multiple simultaneous distraction of the two parts of the intermediate fragment
a b c
d e
Treatment of Noninfected Nonunions: Atrophic Nonunions 185
Fig. 10 a, b.Same case as in Fig. 8.
X-rays at the end of the treat- ment (after 8 months) show for- mation of two bone regenerates of very good quality and con- solidation at the docking site
a
b
Results
The average period of treatment was 7 months (range 5–11 months). No intra- operative complications developed. Postoperative complications were: super- ficial infection in 15 cases and wires breaking in five cases; no vascular or nervous complication were observed.
Consolidation at the docking site was achieved in 57 cases; formation of regenerating bone was regular in all these patients. In the four patients in whom consolidation was delayed, a bone grafting was performed.
A residual deformity, represented by a slight angular deformity at the pre- vious nonunion site (max 4°), was observed in five cases. The articular func- tion was good during the treatment, with a moderate limitation of knee flex- ion, and ankle flexion and extension. It had become almost normal a few weeks after the treatment ended and the fixator was removed.
Discussion
Corticotomy creates an important effect, which has been well described by some Authors who studied and employed the parafocal osteotomy techniques [5–7] and then the corticotomy techniques [3, 8, 9]. Vascularization of the whole bone segment increases greatly, enabling a good quality of regenerat- ing bone (even in elderly patients) at the distraction site, and the develop- ment of bone callus at the previous nonunion site. Moreover, it has a stimu- lating effect on the surrounding soft tissues.
References
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