Title Full coverage of tibial cutting surface on coronal plane causes posterior protrusion of the tibial component in Hintegra TAA

Transcription

1 Title Full coverage of tibial cutting surface on coronal plane causes posterior protrusion of the tibial component in Hintegra TAA Author List: Department of Orthopaedic Surgery, 1. Additional Author: Woo-chun Lee 2. Presenting Author: Dong-il Chun* 3. Additional Author: Jaeho Cho 4. Additional Author: Chulhyun Park** 5. Additional Author: Hongjoon Choi*** 6. Additional Author: Kang Lee**** Seoul Foot & Ankle Center, Seoul Paik Hospital Inje University, Soonchunhyang Univ. Hosp. Seoul Korea*, Young Nam Univ. Hosp. Dae-gu, Korea**, Haeundae Paik Hospital Inje University***, Kangwon National Univ. Hosp.****

2 AOFAS DISCLOSURE SLIDE FORMAT NO CONFLICT TO DISCLOSE Title : Full coverage of tibial cutting surface on coronal plane causes posterior protrusion of the tibial component in Hintegra TAA < Presenter s Name > Dong-il Chun My disclosure is in the Final AOFAS Mobile App. I have no potential conflicts with this presentation.

3 Introduction The use of the appropriate sized tibial component is important in total ankle replacement(tar). Oversized or undersized tibial component relative to the tibial cutting surface would results in different postoperative complications. However it is very difficult to choose a tibial component which fits the tibial cutting surface in medial-lateral width and anteroposterior distance. The hypothesis of this study was that if the width of the ankle mortis was widened due to medial erosion or the anteroposterior distance was shortened as the tibial plafond was cut in proximal location, then the tibial component is likely to be protruding posteriorly in sagittal plane. The aim of this study was to investigate whether the tibial component of the Hintegra total ankle prosthesis was properly designed to cover the tibial cutting surface completely.

4 Methods This retrospective study included 74 patients(74 ankles, including 30 men and 43 women, with an average age of 62.6 years) with osteoarthritis. Who underwent TAR using Hintegra prosthesis between December, 2009 and January, The relationship between the adequacy of coverage of the tibial cutting surface and posterior protrusion of the tibial component was investigated. The relationship between the adequacy of coverage of the tibial cutting surface and posterior protrusion of the tibial component was investigated.

5 Methods Coverage of the tibial cutting surface was assessed on anteroposterior(ap) and lateral radiographs. Depending on the coverage of tibial component on postoperative AP radiographs, the cases were classified as complete and incomplete coverage<fig 1>. <fig 1> Complete coverage Incomplete coverage (>2mm)

6 Methods Mortise widening was defined as talar center was migrated at least 4mm to medial side from tibial axis<fig 2>. <fig 2> No mortis widening Mortis widening (>4mm)

7 Methods Posterior protrusion of the tibial component was defined as posterior protrusion of the tibial component relative to the posterior end of the cutting surface by at least 2mm on post-operative lateral radiographs<fig 3>. <fig 3> Post. protrusion (>2mm) No post. protrusion

8 Methods Proximal cutting of the tibial plafond was defined when the tibial cutting surface was elevated more than 5mm postoperatively compared to the preoperative level of the tibial plafond. The level of the tibial cutting surface or the tibial plafond was determined by the distance between the tibial plafond and the Chaput tubercle<fig 4>. Relationship between the adequacy on AP and lateral radiograph was statistically analyzed by Fisher s exact test <fig 4> Pre op. Post op. a b Elevation (a-b>5mm)

9 Results The relationship between coverage of tibial cutting surface and posterior protrusion on postoperative lateral radiographs is described on <Table 1>(p=0.07). Complete coverage on AP view Incomplete coverage on AP view Post. protrusion on lateral view No post. Protrusion on lateral view <Table 1> The relationship of coverage & post. protrusion. The relationship between mortis widening on preoperative AP radiographs and posterior protrusion on postoperative lateral radiographs is described on <Table 2>(p=0.02). Post. protrusion on lateral view No post. protrusion on lateral view Widened mortis Not widened mortis <Table 2> The relationship of Mortis widening & post. protrusion.

10 Results And the relationship between upward migration of cutting surface and posterior protrusion on postoperative lateral radiographs is described on <Table 3>(p=0.034). Upward migration of cutting surface No upward migration of cutting surface Post. protrusion No post. Protrusion on lateral view (matching) on lateral view <Table 3>The relationship of Mortis widening & post. protrusion. Conclusion In conclusion, increase of width/length ratio of the tibial component of the Hintetra total ankle prosthesis would be helpful for full coverage of the tibial cutting surface without posterior protrusion in ankles with mortise widening or proximal erosion.

11 References 1. Christy M. King, John M. Schuberth, Jeffrey C. Christensen. Relationship of Alignment and Tibial Cortical Coverage to Hypertrophic Bone Formation in Salto Talaris Total AnkleArthroplasty The Journal of Foot & Ankle Surgery 52 (2013) Jean-Luc Besse, Nuno Brito, Christophe Lienhart. Clinical Evaluation and Radiographic Assessment of Bone Lysis of the AES Total Ankle Replacement. Foot & Ankle International/Vol. 30, No. 10/October Francesco Cenni, Alberto Leardini, Andrea Cheli, Fabio Catani. Position of the prosthesis components in total ankle replacement and the effect on motion at the replaced joint. International Orthopaedics (SICOT), 17 June 2011 / Accepted: 6 July 2011, published online: 26 July 2011