Improvement in the clinical practicability of roentgen stereophotogrammetric analysis (RSA): Free from the use of the dual X-ray equipment

Abstract

After total knee replacement, the monitoring of the prosthetic performance is often done by roentgenographic examination. However, the two-dimensional (2D) roentgen images only provide information about the projection onto the anteroposterior (AP) and mediolateral (ML) planes. Historically, the model-based roentgen stereophotogrammetric analysis (RSA) technique has been developed to predict the spatial relationship between prostheses by iteratively comparing the projective data for the prosthetic models and the roentgen images. During examination, the prosthetic poses should be stationary. This should be ensured, either by the use of dual synchronized X-ray equipment or by the use of a specific posture. In practice, these methods are uncommon or technically inconvenient during follow-up examination. This study aims to develop a rotation platform to improve the clinical applicability of the model-based RSA technique. The rotation platform allows the patient to assume a weight-bearing posture, while being steadily rotated so that both AP and ML knee images can be obtained. This study uses X-ray equipment with a single source and flat panel detectors (FPDs). Four tests are conducted to evaluate the quality of the FPD images, steadiness of the rotation platform, and accuracy of the RSA results. The results show that the distortion-induced error of the FPD image is quite minor, and the prosthetic size can be cautiously calibrated by means of the scale ball(s). The rotation platform should be placed closer to the FPD and orthogonal to the projection axis of the X-ray source. Image overlap of the prostheses can be avoided by adjusting both X-ray source and knee posture. The device-induced problems associated with the rotation platform include the steadiness of the platform operation and the balance of the rotated subject. Sawbone tests demonstrate that the outline error, due to the platform, is of the order of the image resolution (= 0.145 mm). In conclusion, the rotation platform with steady rotation, a knee support, and a handle can serve as an alternative method to take prosthetic images, without the loss in accuracy associated with the RSA method.

Keywords

Roentgen stereophotogrammetric RSA knee rotation platform

Get full access to this article

View all access options for this article.

References

Kärrholm

. Roentgen stereophotogrammetry. Review of orthopaedic applications. Acta Orthop Scand 1989; 60: 491–503.

Kärrholm

Gill

RHS

Valstar

. Radiostereometry (RSA): an accurate tool to assess micromotion of orthopaedic implants. In: 53rd annual meeting of the Orthopaedic Research Society, Workshop 7, San Diego, CA, 2007.

Valstar

Gill

Ryd

. Guidelines for standardization of radiostereometry (RSA) of implants. Acta Orthop 2005; 76: 563–572.

Vrooman

Valstar

Brand

. Fast and accurate automated measurements in digitized stereophotogrammetric radiographs. J Biomech 1998; 31: 491–498.

Valstar

Vrooman

Toksvig-Larsen

. Digital automated RSA compared to manually operated RSA. J Biomech 2000; 33: 1593–1599.

Valstar

Jong

FWD

Vrooman

. Model-based roentgen stereophotogrammetry of orthopaedic implants. J Biomech 2001; 34: 715–722.

Kaptein

Valstar

Stoel

. A new model-based RSA method validated using CAD models and models from reversed engineering. J Biomech 2003; 36: 873–882.

Kaptein

Valstar

Stoel

. Evaluation of three pose estimation algorithms for model-based roentgen stereophotogrammetric analysis. Proc IMechE, Part H: J Engineering in Medicine 2004; 218: 231–238.

Hanson

Suggs

Freiberg

. Investigation of in vivo 6DOF total knee arthroplasty kinematics using a dual orthogonal fluoroscopic system. J Orthop Res 2006; 24: 974–981.

10.

Bingham

. An optimized image matching method for determining in-vivo TKA kinematics with a dual-orthogonal fluoroscopic imaging system. J Biomech Eng 2006; 128: 588–595.

11.

Banks

Hodge

. Accurate measurement of three-dimensional knee replacement kinematics using single-plane fluoroscopy. IEEE Trans Biomed Eng 1996; 43: 638–649.

12.

Trozzi

Kaptein

Garling

. Precision assessment of model-based RSA for a total knee prosthesis in a biplanar set-up. Knee 2008; 15: 396–402.

13.

Hoff

Komistek

Dennis

. Three-dimensional determination of femoral-tibial contact positions under in viva conditions using fluoroscopy. Clin Biomech (Bristol, Avon) 1998; 13: 455–472.

14.

Zuffi

Leardini

Catani

. A model-based method for the reconstruction of total knee replacement kinematics. IEEE Trans Med Imaging 1999; 18: 981–991.

15.

Mahfouz

Hoff

Komistek

. A robust method for registration of three-dimensional knee implant models to two-dimensional fluoroscopy images. IEEE Trans Med Imaging 2003; 22: 1561–1574.

16.

Seiber

. Flat-panel detectors: how much better are they? Pediatr Radiol 2006; 36: 173–181.

17.

Hamai

Moro-oka

Miura

. Knee kinematics in medial osteoarthritis during in vivo weight-bearing activities. J Orthop Res 2009; 27: 1555–1561.

18.

Lai

Dai

Syu

. A new registration method for three-dimensional knee nearthrosis model using two X-ray images. Comput Methods Biomech Biomed Engin 2010; 13: 265–278.