Preoperative digital planning versus postoperative outcomes in total hip arthroplasty using a calcar-guided short stem: frequent valgization can be avoided
- 567 Downloads
Modern total hip arthroplasty is largely dependent on the successful preservation of hip geometry. Thus, a successful implementation of the preoperative planning is of great importance. The present study evaluates the accuracy of anatomic hip reconstruction predicted by 2D digital planning using a calcar-guided short stem of the newest generation.
A calcar-guided short stem was implanted in 109 patients in combination with a cementless cup using the modified anterolateral approach. Preoperative digital planning was performed including implant size, caput–collum–diaphyseal angle, offset, and leg length using mediCAD II software. A coordinate system and individual scale factors were implemented. Postoperative outcome was evaluated accordingly and was compared to the planning.
Intraoperatively used stem sizes were within one unit of the planned stem sizes. The postoperative stem alignment showed a minor and insignificant (p = 0.159) mean valgization of 0.5° (SD 3.79°) compared to the planned caput–collum–diaphyseal angles. Compared to the planning, mean femoral offset gained 2.18 (SD 4.24) mm, while acetabular offset was reduced by 0.78 (SD 4.36) mm during implantation resulting in an increased global offset of 1.40 (SD 5.51) mm (p = 0.0094). Postoperative femoroacetabular height increased by a mean of 5.00 (SD 5.98) mm (p < 0.0001) compared to preoperative measures.
Two-dimensional digital preoperative planning in calcar-guided short-stem total hip arthroplasty assures a satisfying implementation of the intended anatomy. Valgization, which has been frequently observed in previous short-stem designs, negatively affecting offset, can be avoided. However, surgeons have to be aware of a possible leg lengthening.
KeywordsTotal hip arthroplasty Short stem Stem alignment Offset Valgization Digital planning Optimys
We thank Dominik Pfluger (numeric data GmbH) for supporting statistical analysis.
Compliance with ethical standards
Conflict of interest
JP has received and may further receive payments or benefits from Mathys Ltd., Switzerland. KPK and MPK certify that they have no conflict of interest (e.g., consultancies, stock ownership, equity interest, patent/licensing arrangements) in connection with this article.
- 3.Babisch J (2013) Möglichkeiten der patientenindividuellen Hüftgelenkrekonstruktion und Knochenresektion bei Kurzschaftprothesen. In: Jerosch J (ed) Kurzschaftendoprothesen—Wo liegen die Unterschiede?. Deutscher Ärzte-Verlag, KölnGoogle Scholar
- 10.McGrory BJ, Morrey BF, Cahalan TD, An KN, Cabanela ME (1995) Effect of femoral offset on range of motion and abductor muscle strength after total hip arthroplasty. J Bone Joint Surg (Br) 77:865–869Google Scholar
- 15.Davilla JA, Kransdorf MJ, Duffy GP (2006) Surgical planning of total hip arthroplasty: accuracy of computer-assisted EndoMap software in predicting component size. Skelet Radiol 35:309–393Google Scholar
- 23.Schröder SM (2011) Prädiktion und Qualitätsverbesserung in der Hüftendoprothetik durch digitale Planung bezüglich des Prothesentyps, der Prothesengröße, der Beinlänge, des Offsets und des Pfannenreinigungswinkels. Dissertation, University of Heidelberg, Germany. http://katalog.ub.uni-heidelberg.de/cgi-bin/titel.cgi?katkey=67198808
- 29.Gargiulo P, Petursson T, Magnusson B, Bifulco P, Cesarelli M, Izzo GM, Magnusdottir G, Halldorsson G, Ludvigsdottir GK, Tribel J, Jonsson H Jr (2013) Assessment of total hip arthroplasty by means of computed tomography 3D models and fracture risk evaluation. Artif Organs 37:567–573CrossRefPubMedGoogle Scholar
- 38.Jerosch J (2012) Kurzschaftendoprothesen: Wo liegen die Unterschiede?. Deutscher Ärzteverlag, Cologne, p 234Google Scholar