A New Tool for Measuring Cup Orientation in Total Hip Arthroplasties from Plain Radiographs

Liaw, Chen Kun; Hou, Sheng; Yang, Rong‐Sen; Wu, Tsung-Han; Fuh, Chiou-Shann

doi:10.1097/01.blo.0000223988.41776.fa

Cited by 93 publications

(119 citation statements)

References 9 publications

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“…The radiological analysis comparing the initial postoperative radiographs with those taken at 5 years was undertaken by one of two independent observers (NH, HS), neither of whom was involved in any of the primary procedures. AP pelvic radiographs were assessed for any change in acetabular version using the method described by Liaw et al [13]. Inclination was also measured off the AP pelvis radiograph using a horizontal line between the teardrops as the transverse axis and the angle was taken between this and the face of the acetabular component.…”

Section: Methodsmentioning

confidence: 99%

Does a Titanium-coated Polyethylene Press-fit Cup Give Reliable Midterm Results?

Hooper

Sargeant

Frampton

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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Background Uncemented acetabular components have demonstrated low revision rates and high patient satisfaction but with concerns regarding increased costs compared with monoblock cups. Some newer lower-cost uncemented monoblock options have become available in the last decade, but limited data are available on their performance. Questions/purposes (1) Does an uncemented, titaniumbacked all-polyethylene acetabular cup provide reliable fixation? (2) What is the frequency and what are the causes for revision with this cup?Methods Between 2004 and 2008, we elected to use an uncemented, titanium-backed all-polyethylene acetabular cup in older patients with limited physical demands. We performed 615 hip replacements in 550 patients with greater than 5 years of clinical and radiographic followup. When patients who were dead (80 hips in 75 patients), lost to followup (98 hips in 93 patients), or revised (three hips in three patients) were excluded, there were 434 hips in 379 patients for comparison of the postoperative and 5-year radiographs. Two observers not involved in the index surgical procedures (NH, HS) assessed radiographs for signs of migration or loosening. Some degree of early movement sometimes is seen before cup stabilization; however, to be conservative, we defined cups with greater than 3°of change of position (even if they subsequently stabilized) as potentially at risk and report them separately. Revision surgery, time from the index procedure, and the reason for revision were recorded from the New Zealand Joint Registry. Results By 5 years there was a median change in inclination of 2°(range, 0°-13°; 95% confidence interval [CI], 2.0-2.4; p \ 0.001) and 2°of anteversion (range, 0°-11°; 95% CI, 2.0-2.4; p \ 0.001). Although at last followup all cups appeared to have stabilized with no radiolucent lines or medial migration, 22% of the cups (94 of 434) had moved more than 3°and so were deemed to be potentially at risk. There were 11 revision procedures (of 429 hips; 2.5%) of which six were for recurrent dislocation, four for femoral fracture, and one for femoral loosening to give an overall all-cause revision rate for all components of 0.25 per 100 component years (95% CI, 0.13-0.43). No revisions were performed for acetabular loosening. Conclusions The short-to medium-term results of this allpolyethylene monoblock cup demonstrated a low frequency of revision. However, 94 cups were identified as potentially

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Section: Methodsmentioning

confidence: 99%

Does a Titanium-coated Polyethylene Press-fit Cup Give Reliable Midterm Results?

Hooper

Sargeant

Frampton

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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“…Because of the symmetry of the ellipse, angle is equal to angles , , and . We previously used a special protractor to measure angle for acetabular radiographic version [7]. radiographs (both clinical and synthetic) using Wan's method with and without mathematical correction.…”

Section: Methodsmentioning

confidence: 99%

“…Random inclination was used because the inclination does not influence the radiographic version [7,16].…”

Section: Methodsmentioning

confidence: 99%

“…According to the well-accepted trigonometric method of measuring acetabular radiographic version [2,4,7,16],…”

Section: Methodsmentioning

confidence: 99%

“…Measuring methods fall into three major groups: the trigonometric group [2,[4][5][6], the protractor group [7][8][9][10], and the computed tomography (CT) group [11][12][13]. Methods in the trigonometric group usually require a ruler and an engineering calculator; those in the protractor group require specialized protractors; and those in the CT group entail excessive radiation and high cost.…”

Section: Introductionmentioning

confidence: 99%

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Direct measurement of acetabular radiographic version using an ordinary goniometer – a precision study

Liaw

Yang

Hsu

et al. 2011

Computer Aided Surgery

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(2011) Direct measurement of acetabular radiographic version using an ordinary goniometer -a precision study, Computer Aided Surgery, 16:4, 196-201, DOI: 10.3109/10929088.2011 Abstract Objective: The acetabular version following total hip arthroplasty is an important prognostic factor. Computer navigation serves as a precise tool during hip arthroplasty, which requires precise measurement to verify the effect of the procedure. Wan and colleagues have reported an innovative method for measuring acetabular radiographic version with an ordinary goniometer. Our objective was to study the precision of this method. Methods: We derived the underlying mathematical principle of Wan's method and produced a correction formula and chart. Forty-eight computer-synthesized radiographs were used to study the method and its mathematical correction. Ten real radiographs were used to detect intra-observer difference. The paired t-test was used for statistical analysis. Results: There was a significant difference between synthetic acetabular radiographic version and the measurement obtained with Wan's method ( p50.05), but there was no difference after mathematical correction ( p ¼ 0.15). For smaller radiographic version (520 o ), there was no statistical difference using Wan's method ( p ¼ 0.054). Conclusions: The method of Wan and colleagues can be used when acetabular radiographic version is less than 20 . For larger radiographic versions, however, mathematical correction is necessary to obtain precise results.

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Standardized fluoroscopy‐based technique to measure intraoperative cup anteversion

Zingg¹,

Boudabbous²,

Hannouche³

et al. 2017

Journal Orthopaedic Research

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Direct anterior approach (DAA) with the patient lying supine has facilitated the use of intraoperative fluoroscopy and allows for standardized positioning of the patient. The current study presents a new technique to measure acetabular component anteversion using intraoperative fluoroscopy. The current paper describes a mathematical formula to calculate true acetabular component anteversion based on the acetabular component abduction angle and the c-arm tilt angle (CaT). The CaT is determined by tilting the c-arm until an external pelvic oblique radiograph with the equatorial plane of the acetabular component perpendicular to the fluoroscopy receptor is obtained. CaT is determined by direct reading on the C-arm device. The technique was validated using a radiopaque synbone model comparing the described technique to computed tomography anteversion measurement. The experiment was repeated 25 times. The difference in anteversion between the two measuring techniques was on average 0.2° (range -3.0-3.1). The linear regression coefficients evaluating the agreement between the experimental and control methods were 0.99 (95%CI 0.88-1.10, p < 0.001) and 0.33 (95%CI -1.53-2.20, p = 0.713) for the slope and intercept, respectively. The current study confirms that the described three-step c-arm acetabular cup measuring technique can reproducibly and reliably assess acetabular component anteversion in the supine position, as compared to CT-imaging. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2307-2312, 2017.

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A New Tool for Measuring Cup Orientation in Total Hip Arthroplasties from Plain Radiographs

Cited by 93 publications

References 9 publications

Does a Titanium-coated Polyethylene Press-fit Cup Give Reliable Midterm Results?

Does a Titanium-coated Polyethylene Press-fit Cup Give Reliable Midterm Results?

Direct measurement of acetabular radiographic version using an ordinary goniometer – a precision study

Standardized fluoroscopy‐based technique to measure intraoperative cup anteversion

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