The adductor tubercle as an important landmark to determine the joint line level in total knee arthroplasty: from radiographs to surgical theatre

Knee Surg Sports Traumatol Arthrosc (2014) 22:30343038 DOI 10.1007/s00167-013-2809-0

KNEE

The adductor tubercle as an important landmark to determine the joint line level in total knee arthroplasty: from radiographs to surgical theatre

F. Iacono G. F. Raspugli D. Bruni G. Filardo

S. Zaffagnini W. F. Luetzow M. Lo Presti I. Akkawi

G. M. Marcheggiani Muccioli M. Marcacci

Received: 15 October 2013 / Accepted: 30 November 2013 / Published online: 22 December 2013 Springer-Verlag Berlin Heidelberg 2013

AbstractPurpose The restoration of the normal joint line (JL) is important both in primary and revision total knee arthroplasty (TKA). However, the assessment of the femorotibial JL is still controversial. A strong correlation between femoral width (FW) and distance from adductor tubercle (AT) to JL was found on radiographs, with a ratio of 0.54. The hypothesis was that this ratio was applicable also in the surgical theatre by using measurements obtained intraoperatively with a caliper.

Methods Femoral width, AT to JL distance and the RATIO between AT to JL distance and FW of 40 patients who underwent TKA were measured on radiograph and intraoperatively. BlandAltman agreement tests with repeated measurements and linear regression analysis were used. The ratio was used to estimate the distance between JL and AT. Results The AT to JL distance/FW ratio calculated with linear regression resulted 0.54 for radiographic

measurements and 0.53 for intra-operative measurements. There was no difference (0.009 0.03) between the calculated ratios on radiographic and intra-operative measurements, and the correlation between intra-operative and radiographic measurements was 0.5 (p = 0.0016). Conclusions This study shows that the validity of the radiographic method which uses an AT to JL distance/FW ratio to determine the level of the JL is conrmed also when using intra-operatively acquired measurements. Thus, this ratio represents a reliable tool to determine the JL level even in challenging prosthetic revision cases when the anatomical JL is missing.

Level of evidence Case series, Level IV.

Keywords Joint line Total knee arthroplasty

Adductor tubercle Radiograph Femoral width

Knee surgery Ratio

F. Iacono (&) G. F. Raspugli D. Bruni G. Filardo

S. Zaffagnini M. Lo Presti I. Akkawi

G. M. M. Muccioli M. Marcacci

2nd Orthopaedics and Traumatologic Clinic, Rizzoli Orthopaedic Institute, Via Pupilli 1, 40136 Bologna, Italy e-mail: [email protected]

G. F. Raspuglie-mail: [email protected]