Purpose: Little has been written about the size of bone defect that could be restored with one-stage lengthening over a reamed intramedullary nail. The aim of this study was to investigate the mechanical properties of the callus created at gaps of various sizes in sheep tibiae treated with reamed intramedullary nailing.

Material-Methods: Sixteen adult female sheep were divided into four main groups: a simple osteotomy group (group I) and three segmental defect groups (1, 2, and 3 cm gap; groups I to III). One intact left tibia from each group was also used as the non-osteotomized intact-control group (group V). In all cases the osteotomy was fixed with an interlocked Universal Humeral Nail after 7 mm reaming. The osteotomized site was closed in layers including the periosteum without additional bone grafting and the limb was protected with long soft cast for 5 weeks postoperatively. Healing of the osteotomies was evaluated after 16 weeks by biomechanical testing. The examined parameters were torsional stiffness, shear stress and angle of torsion at the time of fracture.

Results: Samples with a simple osteotomy or 1 cm gap were fractured distally to the callus zone, whereas samples with 2 and 3 cm gaps were fractured at the callus zone or at distal metaphysis. The regenerate bone obvious in the x-rays in the group of 1 cm and 2 cm gap had considerable mechanical properties. Torsional stiffness in these two groups was nearly similar and its value was about 60% of the stiffness of the simple osteotomy group. A gradually decreased stiffness was observed as the osteotomy gap increased. There was a decrease in maximum shear stress from simple osteotomy to osteotomy with a fracture gap of 3 cm. No significant differences were found among the angles of torsion at fracture for the various osteotomies or the intact bone. Our results showed that the group of 1 cm gap had the 65% of the shear stress at failure of the simple osteotomy group.

Conclusion: We believe that there is evidence indicating that intramedullary nailing would be a reasonable option when one-stage lengthening of a long bone of 1 or 2 cm is contemplated.

Aim: End result study of closed intramedullary nailing of humerus fractures.

Materials & methods: Between 1995–2003, 42 patients with fracture of the humeral shaft, were selected to be treated by I.N. The average age was 48 years old (17years–82years) The Selection criteria were: α) loss of closed reduction (24 patients), b) pathological fractures (5 patients), c) non-union following external fixation (2 patients) and d) delay of union (7 patients). The intramedullary nail was inserted through a proximal entry point via a transdeltoid incision. In 25 cases the entry point was below the greater tuberosity to avoid rotator cuff injury and in 18 cases the entry point was intraarticular. All nails were locked either proximal (41) or distally (1). Open technique was required for 21 cases. Passive full range of motion of elbow and shoulder joint was encouraged after the second postoperative day. Active assisted exercises were initiated the second postoperative week. Bone healing was confirmed by clinical and radiological findings. Shoulder mobility was evaluated by the Constant-Murley scoring system.

Results: The average follow-up time was 21 months (9 months–8 years).All fractures were finally healed. The average healing time was 13 weeks (8weeks–13weeks). Patients with extraarticular entry point of the nail had full passive shoulder motion between the 2th and the 4th postoperative week, whereas patients with intraarticular nail application presented delayed passive shoulder motion with final limitation of the normal range of motion. Seven patients had painful shoulder motion 3 months postoperatively. There were 4 patients with neurapraxia of the radial nerve installed posttraumatic, who had full recovery 3 months later. There was one proximal migrated nail, which required revision. None of the patients required nail removal.

Conclusions: Intramedullary nailing of humeral shaft fractures seems to be a reliable method of treatment. Shoulder mobilization after anterograde insertion of the nail can be easily restored with proper choice of entry point and proper physiotherapy program. The advantages of this method include: shorter operative time, less blood loss, small incision with minimal soft tissue damage. Extraarticular nail insertion should be the entry point of choice as there is no trauma to the rotator cuff.