Reduced Variability of Acetabular Cup Positioning with Use of an Imageless Navigation System

Nogler, Michaël; Kessler, Oliver; Prassl, Alexandra; Donnelly, Bill; Streicher, Robert; Sledge, John B.; Krismer, Martin

doi:10.1097/01.blo.0000141902.30946.6d

Cited by 157 publications

(71 citation statements)

References 15 publications

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“…Precision in the computer-navigated anteversion values was approximately three times better than precision seen in the estimate of cup anteversion made by an experienced surgeon in that study. Similarly, Nogler et al [26] and Haaker et al [9] studied conventional cup placement with navigated cup placement via postoperative CT scanning. With surgeons in both studies attempting to place the acetabular component with 45°abduction and 20°anteversion, these studies also showed cups placed with computer navigation were more accurately placed, had lower standard deviations, and had fewer outliers.…”

Section: Discussionmentioning

confidence: 99%

CT Outperforms Radiography for Determination of Acetabular Cup Version after THA

Ghelman

Kepler

Lyman

et al. 2009

Clinical Orthopaedics &Amp; Related Research

104

102

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Precise evaluation of acetabular cup version is necessary for patients with recurrent hip dislocation after THA. We retrospectively studied 42 patients, who underwent THAs, with multiple cross-table lateral radiographs and CT scans to determine whether radiographic or CT measurement of acetabular component version is more accurate. One observer measured cup version on all radiographs. CT scans were interpreted by one observer. Twenty radiographs were measured twice each by two observers to determine intraobserver and interobserver reliability. We implanted cups in four model pelvises using navigation and compared measurements of anteversion made with radiographs and CT scans. Intraclass correlation coefficients (ICC) for anteversion measurements of two observers were 0.9990 and 0.9998, respectively, when comparing measurements of identical radiographs (intraobserver). Paired values for two observers measuring the same radiograph had an ICC of 0.9686 (interobserver) compared with 0.7412 for measurements from serial radiographs of the same component. The ICC comparing radiographic versus CT-based measurements was 0.6981. CT measurements had stronger correlations with navigated values than radiographic measurements. Accuracy of anteversion measurements on crosstable radiographs depends on radiographic technique and patient positioning whereas properly performed CT measurements are independent of patient position.

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Section: Discussionmentioning

confidence: 99%

CT Outperforms Radiography for Determination of Acetabular Cup Version after THA

Ghelman

Kepler

Lyman

et al. 2009

Clinical Orthopaedics &Amp; Related Research

104

102

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“…Only one cadaver was used. However, published studies and our prior study used only limited numbers of cadaver specimens [17,29,35,38,40]. In clinical practice, there undoubtedly would be more variability for imageless referencing if more specimens would have been used.…”

Section: Discussionmentioning

confidence: 98%

“…In our example, we chose 10°above and below the reference position based on the historical comparison of Lewinnek et al [25]. To analyze the comparative ability of the Six Sigma ratio, we evaluated other similar computer navigation acetabular studies that adequately reported descriptive statistics [9,17,29,35,37,40] ( Table 3). CT for navigation referencing provided satisfactory precision, whereas fluoroscopy was capable in some studies but not in others.…”

Section: Discussionmentioning

confidence: 99%

“…For computer navigation, the APP was determined. Recent studies have advanced the use of this structure because of the definable landmarks presented [19,26,29,35,37,43]. For purposes of this investigation, the APP was defined as the plane defined by the most anteriorly prominent aspect of the two ASISs and the most prominent anterior portion of the symphysis pubis.…”

Section: Methodsmentioning

confidence: 99%

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Six Sigma Analysis of Minimally Invasive Acetabular Arthroplasty: A Preliminary Investigation

Heck¹,

Stiehl

2009

Clinical Orthopaedics &Amp; Related Research

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Minimally invasive techniques in THA may increase the difficulty of acetabular component insertion relative to the optimized position. We sought to determine the ability of eight surgeons to position an acetabular component placed using an anterior-lateral minimally invasive surgical (MIS) approach with conventional instruments or computer navigation using an optical imageless protocol compared with conventional true values determined by computed tomography (CT). We introduce a new approach, the Six Sigma process capability index, to assess outliers. Using the Six Sigma process capability index (Cp [ 1.3) and the criteria of Lewinnek et al. of ± 10°for adequate precision, three-dimensional (3D) CT was capable for inclination and anteversion. Computer navigation and visual cues with conventional instrumentation were precise for anteversion but not for inclination. We conclude image-free computer navigation was not better than conventional instrumentation with the surgeons' visual cues for acetabular cup placement. Six Sigma analysis allows comparison of various methods of referencing with literature controls, and our data suggest CT referencing is the most precise method.

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“…Accordingly, the use of computer navigation in total joint arthroplasty has become more prevalent and the method has proved to be reliable for acetabular component positioning. Studies showed higher accuracy in plastic pelvis models [1], in human cadaver models [2] and in clinical use [3]. While there are some randomised controlled trials comparing the use of computer navigation with freehand component placement in a supine position [4], there is, so far, only one randomised study referring cup position to postop 3D computed tomography (CT) measurements in a lateral decubitus position using imageless navigation and a minimally-invasive approach [5].…”

Section: Introductionmentioning

confidence: 99%

Accuracy of acetabular cup placement in computer-assisted, minimally-invasive THR in a lateral decubitus position

Sendtner

Schuster²,

Wörner

et al. 2010

International Orthopaedics (SICOT)

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In a prospective and randomised clinical study, we implanted acetabular cups either by means of an imagefree computer-navigation system (navigated group, n=32) or by free-hand technique (freehand group n=32, two dropouts). Total hip replacement was conducted in the lateral position and through a minimally invasive anterior approach (MicroHip). The position of the component was determined postoperatively on CT scans of the pelvis using CT-planning software. We found an average inclination of 42.3°(range 32.7-50.6°; SD±3.8°) and an average anteversion of 24.5°(range 12.0-33.3°; SD±6.0°) in the computer-assisted study group and an average inclination of 37.9°(range 25.6-50.2°; SD±6.3°) and an average anteversion of 23.8°(range 5.6-46.9°; SD±10.1°) in the freehand group. The higher precision of computer navigation was indicated by the lower standard deviations. For both measurements we found a significant heterogeneity of variances (p<0.05, Levene's test). The mean difference between the cup inclination/anteversion values displayed by computer navigation and the true cup position (CT control) was 0.37°(SD 3.26) and −5.61°(SD 6.48), respectively. We found a bias (underestimation) with regard to anteversion determined by the imageless computer navigation system. A bias for inclination was not found. Registration of the landmarks of the anterior pelvic plane in lateral position with undraped percutaneous methods leads to an error in cup anteversion, but not to an error in cup inclination. The bias we found is consistent with a correct registration of the anterosuperior iliac spine (ASIS) and with a registration of the symphysis 1 cm above the bone, corresponding to the less compressible overlying soft tissue in this region. There was no significant correlation between the bias and the thickness of soft tissue above the pubic tubercles. We suggest use of a percutaneous registration of ASIS and an invasive registration above the pubic tubercles when computer-assisted navigation is performed in minimally invasive THR in a lateral position.

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Reduced Variability of Acetabular Cup Positioning with Use of an Imageless Navigation System

Cited by 157 publications

References 15 publications

CT Outperforms Radiography for Determination of Acetabular Cup Version after THA

CT Outperforms Radiography for Determination of Acetabular Cup Version after THA

Six Sigma Analysis of Minimally Invasive Acetabular Arthroplasty: A Preliminary Investigation

Accuracy of acetabular cup placement in computer-assisted, minimally-invasive THR in a lateral decubitus position

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