Olecranon anatomy:Use of a novel proximal interlocking screw for intramedullary nailing,a cadaver study

AIM: To define the optimum safe angle of use for an eccentrically aligned proximal interlocking screw(PIS) for intramedullary nailing(IMN).METHODS: Thirty-six dry cadaver ulnas were split into two equal pieces sagitally. The following points were identified for each ulna: the deepest point of the incisura olecrani(A), the point where perpendicular lines from A and the ideal IMN entry point(D) are intersected(C) and a point at 3.5 mm(2 mm safety distance from articular surface + 1.5 mm radius of PIS) posterior from point A(B). We calculated the angle of screws inserted from point D through to point B in relation to D-C and B-C. In addition, an eccentrically aligned screw was inserted at a standard 20° through the anterior cortex of the ulna in each bone and the articular surface wasobserved macroscopically for any damage.RESULTS: The mean A-C distance was 9.6 mm(mean ± SD, 9.600 ± 0.763 mm), A-B distance was 3.5 mm, C-D distance was 12.500 mm(12.500 ± 1.371 mm) and the mean angle was 25.9°(25.9°± 2.0°). Lack of articular damage was confirmed macroscopically in all bones after the 20.0° eccentrically aligned screws were inserted. Intramedullary nail fixation systems have well known biological and biomechanical advantages for osteosynthesis. However, as well as these well-known advantages, IMN fixation of the ulna has some limitations. Some important limitations are related to the proximal interlocking of the ulna nail. The location of the PIS itself limits the indications for which intramedullary systems can be selected as an implant for the ulna. The new PIS design, where the PIS is aligned 20°eccentrically to the nail body, allows fixing of fractures even at the level of the olecranon without disturbing the joint. It also allows the eccentrically aligned screw to be inserted in any direction except through the proximal radio-ulnar joint. Taking into consideration our results, we now use a 20° eccentrically aligned PIS for all ulnas. In our results, the angle required to insert the PIS was less than 20° for only one bone. However, 0.7° difference corresponds to placement of the screw only 0.2 mm closer to the articular surface. As we assume 2.0 mm to be a safe distance, a placement of the screw 0.2 mm closer to the articular surface may not produce any clinical symptoms.CONCLUSION: The new PIS may give us the opportunity to interlock IMN without articular damage and confirmation by fluoroscopy if the nail is manufactured with a PIS aligned at a 20.0° fixed angle in relation to the IMN.

Factors Affecting Time to Healing in Humeral Shaft Fractures Treated with SIGN Intramedullary Nailing

There is a tendency to treat humeral fractures with the use of splintage in resource poor countries due to a perceived high rate of complications with operative fixation. The Surgical Implant Generation Network (SIGN) intra medullary nail has provided an alternative in the management of humeral shaft fractures. Due to the paucity of research work in this area, our study evaluated factors that influence the time to fracture union in humeral shaft fractures. Fifty-eight humeral Diaphysial fractures were treated over six years. It is a retrospective study. Case notes and the database were analysed. The statistical analysis was done using the SPSS 24 software. The time to fracture healing was the primary outcome variable and how it was influenced by patient and implant variables was studied. The mean time to fracture healing was 17.38 weeks. All 58 fractures united. The mean time to fracture healing in the 20 - 29 years was 16.00 weeks which was lower than in older age groups. Fractures in males healed at 16.33 weeks and in females at 18.76 weeks. Patients with Diabetes Mellitus had a mean healing time of 29.00 weeks, while third proximal fractures healed in a mean time of 15.25 weeks. Age and sex had no significant influence on the time to fracture healing while Diabetes Mellitus, longer duration of antibiotic use, open fractures, and presence of fracture gap post fixation and third middle fractures had increased time to fracture healing.

Treatment of femur supracondylar fracture with retrograde interlocking intramedullary nails in elderly patients

Objective： To report 32 cases of femur supracondylar fracture treated with retrograde interlocking intramedullary nails in elderly patients. Methods： According to the AO classification, all of 32 cases were classified as extra-articular type A. 32 cases were treated with interlocking intramedullary nail by closed insertion from intercondylar fossa of the knee. All cases accepted CPM exercise as early as possible after operation. Results： Following up 5 to 15 months, all fractures united within an average duration of 5.3 months （4-7 months）. According to the Shelbourne scale, the excellent rate of the knee function was 86.3%. Conclusion： Retrograde interlocking intramedullary nail is useful alternative implant for the treatment of osteoporotic supracondylar fracture of femur, particularly of the type A fracture in the elderly population. Its merits include stable fixation, high rate of fracture union and few complications.

Fracture Union in Closed Interlocking Nail in Humera Shaft Fractures

Background： Fracture shaft humerus is a major cause of morbidity in patients with upper extremity injuries. The aim of this study was to evaluate the outcome of interlocking nail in humeral shaft fractures. Methods： This study was conducted in the Department of Orthopedic Surgery in SMS and R Sharda University from January 2010 to November 2013. Seventy-eight patients were recruited from emergency and out-patient department having a close fracture of humerus shaft. All patients were operated under general anesthesia and closed reamed interlocking nailing was done. All patients were followed for 9 months. Results： Out of 78 patients, 69 patients underwent union in 90-150 days with a mean of I 10.68 days. Complications found in four patients who had nonunion, and five patients had delayed union, which was treated with bone grafting. All the patients were assessed clinically and radiologically for fracture healing joint movements and implant thilure. The results were excellent in 88.46% and good in 6.41% patients. Complete subjective, functional, and clinical recovery had occurred in almost 100% of the patients. ConcLusions： The results of the present study indicates that in the presence of proper indications, reamed antegrade intramedullary interlocked nailing appears to be a method of choice for internal fixation ofosteoporotic and pathologic fractures.