Intramedullary Pin Fixation in Clavicular Fractures: A Study Comparing the Use of Small and Large Pins

Abstract

The S-shaped clavicle poses a problem for intramedullary pin fixation. Stability of fracture fixation is closely related to the length of intramedullary pin engagement. This study was carried out to determine the engagement length of intramedullary pins into clavicular fractures using a small and a large pin. Seven pairs of fresh cadaveric clavicles were prepared and arranged into Group 1 and Group 2 for paired study. A mid-third clavicular fracture was created at the junction of the two curves of the clavicle. In Group 1, a 3.2 mm diameter threaded Steinman pin was introduced into the medullary canal of the clavicle by retrograde technique and the medial fragment of the fracture was drilled until the pin perforated the bone cortex. In Group 2, a 4 mm diameter threaded Steinman pin was used in the same manner. The results showed that Group 1 had an average engagement of pin into the clavicle of 9.11 cm with a ratio to total length of the clavicle of 0.59. In Group 2, the average engagement length into the clavicle was 7.17 cm with a ratio of 0.47. The difference was significant, with the smaller pin providing better fixation. The pins in both groups perforated the lateral fragment at the posterosuperior aspect and the medial fragment at the anterior aspect of the clavicle. The angle that the pin made with the long axis of the clavicle in Group 1 was 22.43 degrees and in Group 2, 26.57 degrees. Although the 3.2 mm diameter pin was more aligned to the long axis of the clavicle than the 4 mm diameter pin, the difference was not significant.

Meta-analysis of plate fixation versus intramedullary fixation for the treatment of mid-shaft clavicle fractures

“…Therefore, the favorable solutions for this might improve stability in IFs and reduce excessive movement in PFs especially in early-stage, postoperatively. In Harnroongroj’ and Lee’s studies, implant failure was attributed to the length of intramedullary pin engagement and small pin could provide better stability [ 17 , 39 ]. Authors suggested patients treated by PFs should gradually increase should motion range and keep within 90°during the first 3 weeks after surgery [ 21 ].…”

Biomechanical Analysis of Fixation of Middle Third Fractures of the Clavicle

“…[3][4][5][6][7][8][9][10][11] Although various techniques have been advocated for fracture fixation, including plating and intramedullary devices, only a few biomechanical studies provide the treating surgeon with information that may guide the selection of the most appropriate device for surgical repair. [12][13][14][15][16][17][18][19] Plating of middle third clavicular fractures has been supported in clinical studies as a successful and reproducible surgical option. 7,11,[20][21][22][23][24] Although debate has arisen over the ideal location for a plate, 12,19 biomechanical evidence has supported both superior and anterior plate locations depending on the fracture pattern.…”

“…Both clinical and biomechanical studies support the use of intramedullary devices; however, the variability of implant designs has made the selection of the ideal implant difficult. [15][16][17][18] The purpose of this biomechanical study was to address the concept of ideal implant selection for the treatment of middle third clavicular fractures. Using a standardized testing protocol, four implants commonly used in modern orthopaedic practice were tested and compared in a simulated middle third clavicular fracture model.…”

Plate fixation versus intramedullary fixation for midshaft clavicle fractures: Meta-analysis of complications and functional outcomes

“… 40 , 41 Therefore, to prevent this complication, the stability of IF needs to be improved, and excessive movement, especially in the early stages of recovery from PF surgery, should be minimized. 15 , 26 , 42 …”