Biomechanical evaluation of simulated feline patellar fracture repairs

Summary

Objective: To investigate four techniques for stabilization of feline patellar fracture.

Methods: Feline cadaveric stifles with simulated patellar fracture were stabilized with one of four techniques: Group A - circumferential wire, group B - figure-of-eight wire, group C - combined figure-of-eight and circumferential wire, group D - pin and tension band wire. All repairs were subjected to a period of cyclic loading prior to load to failure testing. Experiments were recorded by video capture to determine load at failure and failure mode. Failure was defined as an opening of the fracture gap of 3 mm.

Results: Mean fracture gap opening (±SD) during peak loading after 1000 cycles was: group A with 1.66 mm (± 0.69), group B with 1.01 mm (± 0.45), group C with 0.81 mm (± 0.58), and group D with 0.65 mm (± 0.54). Groups C and D had significantly lower mean fracture gap opening after 1000 cycles when compared to group A (p <0.05). Mean loads (± SD) at failure were: group A with 171.4 N (± 62.2), group B with 208.7 N (± 20.7), group C with 288.2 N (± 62.5), and group D with 219.5 N (± 48.0). Group C had significantly higher mean load to failure than all other groups (p <0.05). There was no difference between other groups. In groups A, B and C the principle mode of failure was wire elongation and tearing of sutures through the retinaculae and periarticular soft tissues. In group D, the principle mode of failure was the pin pulling through the bone of the distal fragment.

Conclusions: Combined figure-of-eight and circumferential wires may be useful for treatment of transverse feline patellar fracture.

Keywords

Patellar fracture - feline - biomechanical - cadaver

• References

• 1 Arnbjerg J., Bindseil E.. Patella Fracture in Cats. Feline Pract 1994; 22: 31-35.
• 2 Guillaumot P., Scotti S., Carozzo C.. et al. Two cases of surgically treated feline patellar fractures. Vet Comp Orthop Traumatol 2008; 21: 156-158.
• 3 Langley-Hobbs SJ.. Survey of 52 fractures of the patella in 34 cats. Vet Rec 2009; 164: 80-86.
• 4 Mason RW., Moore TE., Walker CW.. et al. Patellar fatigue fractures. Skeletal Radiol 1996; 25: 329-332.
• 5 Hermer J., Bush M., Whiting C.. et al. Healing of patellar fractures in two kittens. Vet Comp Orthop Traumatol 2012; 25: 155-159.
• 6 Salas N., Popovitch C.. Surgical versus conservative management of patella fractures in cats: A retrospective study. Can Vet J 2011; 52: 1319-1322.
• 7 Schnabel B., Scharf M., Schwieger K.. et al. Biomechanical comparison of a new staple technique with tension band wiring for transverse patella fractures. Clin Biomech 2009; 24: 855-859.
• 8 Chen A., Hou C., Bao J.. et al. Comparison of biodegradable and metallic tension-band fixation for patella fractures. 38 patients followed for 2 years. Acta orthopaedica Scandinavica 1998; 69: 39-42.
• 9 Liu F., Wang S., Zhu Y.. et al. Patella rings for treatment of patellar fracture. EurJ Orthop Surg Traumatol 2014; 24: 105-109.
• 10 Burvant JG., Thomas KA., Alexander R.. et al. Evaluation of methods of internal fixation of transverse patella fractures: a biomechanical study. J Orthop Trauma 1994; 8: 147-153.
• 11 Banks KE., Ambrose CG., Wheeless JS.. et al. An alternative patellar fracture fixation: a biomechanical study. J Orthop Trauma 2013; 27: 345-351.
• 12 Lin T., Liu J., Xiao B.. et al. Comparison of the outcomes of cannulated screws vs. modified tension band wiring fixation techniques in the management of mildly displaced patellar fractures. BMC Musculoskelet Disord 2015; 16: 282.
• 13 Bostman O., Kiviluoto O., Santavirta S.. et al. Fractures of the patella treated by operation. Arch Orthop Traum Surg 1983; 102: 78-81.
• 14 Gosal HS., Singh P., Field RE.. Clinical experience of patellar fracture fixation using metal wire or non-absorbable polyester—a study of 37 cases. Injury 2001; 32: 129-135.
• 15 Chen CH., Huang HY., Wu T.. et al. Transosseous suturing of patellar fractures with braided polyester - A prospective cohort with a matched historical control study. Injury 2013; 44: 1309-1313.
• 16 Hughes SCA., Stott PM., Hearnden AJ.. et al. A new and effective tension-band braided polyester suture technique for transverse patellar fracture fixation. Injury 2007; 38: 212-222.
• 17 Carpenter JE., Kasman RA., Patel N.. et al. Biomechanical evaluation of current patella fracture fixation techniques. J Orthop Trauma 1997; 11: 351-356.
• 18 Weber MJ., Janecki CJ., Mcleod P.. et al. Efficacy of various forms of fixation of transverse fractures of the patella. J Bone Joint Surg Am 1980; 62: 215-220.
• 19 Curtis MJ.. Internal fixation for fractures of the patella. A comparison of two methods. J Bone Joint Surg Br 1990; 72: 280-282.
• 20 Patel VR., Parks BG., Wang YB.. et al. Fixation of patella fractures with braided polyester suture: a biomechanical study. Injury 2000; 31: 1-6.
• 21 Dargel J., Gick S., Mader K.. et al. Biomechanical comparison of tension band- and interfragmentary screw fixation with a new implant in transverse patella fractures. Injury 2010; 41: 156-160.
• 22 Fortis AP., Milis Z., Kostopoulos V.. et al. Experimental investigation of the tension band in fractures of the patella. Injury 2002; 33: 489-493.
• 23 Agarwala S., Agrawal P., Sobti A.. A novel technique of patella fracture fixation facilitating early mobilization and reducing re-operation rates. J Clin Orthop Trauma 2015; 6: 207-211.
• 24 DeCamp CE.. Chapter 17. Fractures of the femur and patella. In: Piermattei DL., Flo GL., DeCamp CE.. editors. Brinker, Piermattei and Flo’s Handbook of Small Animal Orthopedics and Fracture Repair St. Loius, MO: Elsevier Health Sciences; 2015: 512-561.
• 25 Gibert S., Kowaleski MP., Matthys R.. et al. Biomechanical comparison of pin and tension-band wire fixation with a prototype locking plate fixation in a transverse canine patellar fracture model. Vet Comp Orthop Traumatol 2016; 29: 20-28.
• 26 Benjamin J., Bried J., Dohm M.. et al. Biomechanical evaluation of various forms of fixation of transverse patellar fractures. J Orthop Trauma 1987; 1: 219-222.