Key Insights On Joint Preparation For Arthrodesis

I have recently changed my approach to lecturing by trying to present concepts based on literature instead of the traditional approach. This means I have had to write several new lectures over the past few months, which is both good and bad. It has been good because I have had to literally read hundreds of articles for research. It has been bad for the same reason as the time required to do so is enormous. As I was preparing for a lecture on first metatarsocuneiform joint arthrodesis for the American Society of Podiatric Surgeons meeting in Pittsburgh (an excellent meeting by the way and a great organization that I would highly recommend joining if you are already not a member), I ran across some very interesting concepts that I think warrant some debate. I would like to tackle an issue in each of the next couple of blogs to see what you think about these concepts. The first concept I would like to examine is joint preparation and this really applies to any arthrodesis procedure, not just first metatarsocuneiform joint arthrodesis. Any discussion on joint preparation must start with an anatomical review of the bone-cartilage interface. The subchondral bone plate consists of bone pegs surrounded by calcified cartilage pegs that interlock to prevent shearing with a visible layer of noncalcified cartilage lying over the calcified layer.¹ Ray and colleagues in the Journal of Foot and Ankle Surgery showed that maintaining the subchondral bone plate provides a significantly greater load to failure and bending moment in comparison to subchondral bone plate removal.² Johnson and coworkers in the Journal of Foot and Ankle Surgery examined curettage of the first metatarsocuneiform joint and subtalar joint and subsequently examined specimens histologically.¹ Even with all visible noncalcified cartilage removed, the photomicrograph of the sections still showed a layer of noncalcified cartilage present along with a full layer of calcified cartilage. For an arthrodesis to occur, there must be a conversion of a chondrogenic medium of a diarthrodial joint to a zone of mature trabecular bone.¹ Subchondral bone-derived mesenchymal progenitor cells will differentiate into bone or fibrocartilage based on local cell mediators.^3,4 Authors have advocated subchondral bone drilling and fish scaling for arthrodesis without any scientific basis.^5-7 Subchondral drilling may not provide a significant reduction of surface area of the retained subchondral plate and may cause thermal necrosis of bone despite the improved fixation with maintaining the subchondral bone plate.8 Fish scaling may be more effective in exposing the calcified cartilage to greater numbers of bone healing cells. For first metatarsocuneiform joint arthrodesis, I use a saw to minimally resect the bone just below the subchondral plate and perform transverse plane correction on the cuneiform side of the joint. It is critical to correct all three planes with reduction of the arthrodesis site and reciprocal planning with a saw may assist with this effort. Next month, I will discuss concepts in the fixation of first metatarsocuneiform joint arthrodesis. References 1. Johnson JT, Schuberth JM, Thornton SD, Christensen JC. Joint curettage arthrodesis technique in the foot: a histological analysis. J Foot Ankle Surg. 2009;48(5):558-64. 2. Ray RG, Ching RP, Christensen JC, Hansen ST Jr. Biomechanical analysis of the first metatarsocuneiform arthrodesis. J Foot Ankle Surg. 1998;37(5):376-85. 3. Neumann K, Dehne T, Endres M, et al. Chondrogenic differentiation capacity of human mesenchymal progenitor cells derived from subchondral cortico-spongious bone. J Orthop Res. 2008; 26(11):1449–1156. 4. Otto WR, Rao J. Tomorrow’s skeleton staff: mesenchymal stem cells 
and the repair of bone and cartilage. Cell Prolif. 2004; 37(1):97–110. 5. Yu GV. The curettage technique for major rearfoot fusions. In: Camasta CA, Vickers NS, Ruch JA (eds): The Podiatry Institute Reconstructive Surgery of the Foot and Leg, Update ’93, Podiatry Institute, Tucker, GA, 1993, pp. 260–237. 6. Coetzee JC, Wickum D. The Lapidus procedure: a prospective cohort 
outcome study. Foot Ankle Int. 2004; 25(8):526–531. 7. Patel S, Ford LA, Etcheverry J, Rush SM, Hamilton GA. Modified Lapidus arthrodesis: rate of nonunion in 227 cases. J Foot Ankle Surg. 2004; 43(1):37–42. 8. Eriksson AR, Albrektsson T, Albrektsson B. Heat caused by drilling cortical bone. Temperature measured in vivo in patients and animals. Acta Orthop Scand. 1984; 55(6):629–631.