A biomechanical study comparing two fixation methods in depression fractures of the lateral tibial plateau in porcine bone

Caroline M Blakey1, Michael Rennison2, Stephen P Guy3, Paul M Sutton1
1Department of Orthopaedics, Sheffield Teaching Hospital NHS Trust, Sheffield, UK
2Department of Mechanical Engineering; University of Sheffield; Sheffield UK
3Department of Orthopaedics, Bradford Teaching Hospitals NHS Trust, Duckworth Lane, UK

Tóm tắt

A novel method of fixation has been described for the treatment of pure depression fractures of the lateral tibial plateau. Fracture fragments are elevated through a reamed transtibial tunnel. An interference screw is then passed into the tunnel to buttress fracture fragments from beneath. This method of fixation has perceived benefits but there have been no studies to demonstrate that the technique is biomechanically sound. The aim of our study is to compare traditional parallel, subchondral screw fixation with the use of an interference screw, assessing maintenance of fracture reduction following simulated post-operative loading, and overall construct strength. Depression fractures of the lateral tibial plateau were simulated in 14 porcine knees. Fracture fragments were elevated through a reamed transtibial tunnel and samples were randomly assigned to a fixation method. 7 knees underwent traditional fixation with parallel subcortical cannulated screws, the remainder were stabilized using a single interference screw passed through the transtibial tunnel. Following preloading, each tibia was cyclically loaded from 0 to 500 Newtons for 5,000 cycles using a Nene testing machine. Displacement of the depressed fracture fragments were measured pre and post loading. Samples were then loaded to failure to test ultimate strength of each construct. The depression displacement of the fractures fixed using cannulated screws was on average 0.76 mm, in comparison to 0.61mm in the interference screw group (p=0.514). Mechanical failure of the cannulated screw constructs occurred at a mean of 3400 N. Failure of the transtibial interference screw constructs occurred at a mean of 1700 N (p<0.01). In both groups the mechanism of ultimate failure was splitting of the tibial plateau. These results demonstrate the increased biomechanical strength of parallel, cannulated screws for depression fractures of the tibial plateau, however the use of a transtibial interference screw may be a viable method of fixation under physiological loads.

Tài liệu tham khảo

Atesok K, Doral MN, Whipple T, et al: Arthroscopy-assisted fracture fixation. Knee Surg Sports Traumatol Arthrosc. 2011, 19 (2): 320-329. 10.1007/s00167-010-1298-7. Buchko GM, Johnson DH: Arthroscopy assisted operative management of tibial plateau fractures. Clin Orthop. 1996, 332: 29-36. Lubowitz JH, Guttman D, Elson WS: Part I: arthroscopic management of tibial plateau fractures. Arthroscopy. 2004, 20: 1063-1070. 10.1016/j.arthro.2004.09.001. Watson TJ: Tibia: proximal. AO Principles of Fracture Management. Edited by: Rüedi TP, Murphy WM. 2000, Stuttgart: Thieme, 499-517. Lubowitz JH, Vance KJ, Ayala M, et al: Technical note: interference screw technique for arthroscopic reduction and internal fixation of compression fractures of the tibial plateau. Arthroscopy: The Journal of Arthroscopic and Related Surgery. 2006, 22 (12): 1359-1359. Benoit B, Fouad Z, Laflamme GH, et al: Augmentation of tibial plateau fractures with trabecular metal: a biomechanical study. Journal of Orthopaedic Surgery and Research. 2009, 4: 37-43. 10.1186/1749-799X-4-37. Patil S, Mahon A, Green S, et al: A biomechanical study comparing a raft of 3.5 mm cortical screws with 6.5 mm cancellous screws in depressed tibial plateau fractures. The Knee. 2006, 13: 231-235. 10.1016/j.knee.2006.03.003. Yetkinler DN, McClellan RT, Reindel ES, et al: Bio- mechanical comparison of conventional open reduction and internal fixation versus calcium phosphate cement fixation of a central depressed tibial plateau fracture. J Orthop Trauma. 2001, 15 (3): 197-206. 10.1097/00005131-200103000-00009. Brown T, Anderson DD, Nepola JV, et al: Contact stress aberrations following imprecise reduction of simple tibial plateau fractures. J Ortho Res. 1988, 6: 851-862. 10.1002/jor.1100060609. Honkonen SE: Indications for surgical treatment of tibial condyle fractures. Clin Orthop. 1994, 302: 199-205. Hohl M, Luck JV: Fractures of the tibial condyle a clinical and experimental study. J Bone Joint Surg Am. 1956, 38: 1001-1018. Maquet PGJ, Pelzer GA: Evolution of the maximum stress in osteo-arthritis of the knee. Journal of Biomechanics. 1977, 10 (2): 107-117. 10.1016/0021-9290(77)90074-4. Schatzker J, McBroom R, Bruce D: The tibial plateau fracture: the Toronto experience 1968–1975. Clin Orthop. 1979, 138: 94-104. Aerssens J, Boonen S, Lowet G, et al: Interspecies differences in bone composition, density, and quality: potential implications for in Vivo bone research. Endocrinology. 1998, 139 (2): 663-670. 10.1210/en.139.2.663. The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/2052-1847/5/15/prepub