33rd Annual Scientific Meeting proceedings

Minimally invasive osteosynthesis (MIO) techniques have recently gained popularity in the human and veterinary field. This more biologic method allows for fracture fixation while preserving the surrounding soft tissues/blood supply, minimizing the risk of infection, and providing an earlier return to function.¹ Stabilization of articular fractures using minimally invasive techniques is uniquely challenging as anatomic reduction of the articular surface is essential for optimal outcome. However, assessment of the articular surface during surgery can be challenging due to limited exposure using MIO techniques.

Articular fractures most amenable to MIO include fractures that are acute (24-48 hours old), minimally displaced, simple, have minimal swelling, and are able to be visualized using aids.^1,2 Methods to visualize the articular surface and evaluate fracture reduction intra-operatively include fluoroscopy, mini arthrotomy, arthroscopy, and arthroscopic assisted mini arthrotomy.^1–3  Although perfect anatomic reduction of an articular surface is the goal in surgery, small steps (either less than 2mm or less than the local articular cartilage thickness) may still result in bony repair and restoration of joint congruity.^4,5

Fluoroscopy is often a first-line choice for many surgeons performing MIO techniques. Advantages of fluoroscopy are that it can provide orthogonal views of many joints (particularly those of the mid to distal limb), is readily available in many surgical practices, and can be used intra-operatively allowing for real time adjustments in reduction or implants. Disadvantages of fluoroscopy include a learning curve, cost of the equipment, and exposure to radiation.³

 Arthroscopy is also a valuable tool which can be used to evaluate reduction of articular fractures. In a study of distal radial fracture repair in humans, assessment of the articular surface after reduction was performed with both C-arm and arthroscopy. These authors found that the C-arm often underestimated the width of gapping at the articular surface and assessment using arthroscopy allowed for further manipulation and better reduction of the fracture fragments.⁶ Although helpful for certain fractures, it is still unclear if arthroscopic assessment is needed in each case.⁷ And although not widely used during fracture repair in veterinary medicine, there are some reports in the literature.⁸

In addition to the tools used for assessment of fracture reduction intra-operatively, several implants/implant systems are also available to facilitate minimally invasive repair of articular fractures. These implants can typically be placed through small portals and include K wires, compression screws, headless compression screws, self-compressing pins, cannulated screws, and cannulated self-compressing screws.² As with most minimally invasive techniques, knowing when to abort and convert to open reduction and internal fixation (ORIF) is imperative. Typically, fractures that are more chronic or are non-reducible due to swelling, callus formation, or muscle contraction are better suited to ORIF.¹

1. Cook JL, Tomlinson JL, Reed AL. Fluoroscopically guided closed reduction and internal fixation of fractures of the lateral portion of the humeral condyle: prospective clinical study of the technique and results in ten dogs. Vet Surg. 1999;28(5):315-321. doi:10.1111/j.1532-950x.1999.00315.x
2. Beale BS, Cole G. Minimally invasive osteosynthesis technique for articular fractures. Vet Clin North Am Small Anim Pract. 2012;42(5):1051-1068, viii. doi:10.1016/j.cvsm.2012.07.008
3. Guiot LP, Déjardin LM. Perioperative imaging in minimally invasive osteosynthesis. Vet Clin North Am Small Anim Pract. 2020;50(1):49-66. doi:10.1016/j.cvsm.2019.08.003
4. Lefkoe TP, Trafton PG, Ehrlich MG, et al. An experimental model of femoral condylar defect leading to osteoarthrosis. J Orthop Trauma. 1993;7(5):458-467. doi:10.1097/00005131-199310000-00009
5. Lefkoe TP, Walsh WR, Anastasatos J, Ehrlich MG, Barrach HJ. Remodeling of articular step-offs. Is osteoarthrosis dependent on defect size? Clin Orthop Relat Res. 1995;(314):253-265.
6. Edwards CC, Haraszti CJ, McGillivary GR, Gutow AP. Intra-articular distal radius fractures: arthroscopic assessment of radiographically assisted reduction. J Hand Surg Am. 2001;26(6):1036-1041. doi:10.1053/jhsu.2001.28760
7. Shkolnikova J, Harvey J. Wrist arthroscopy in the management of distal radius fractures. Ann Joint. 2018;3:77-77. doi:10.21037/aoj.2018.08.06
8. Deneuche AJ, Viguier E. Reduction and stabilisation of a supraglenoid tuberosity avulsion under arthroscopic guidance in a dog. J Small Anim Pract. 2002;43(7):308-311. doi:10.1111/j.1748-5827.2002.tb00079.x