The Acetabular Teardrop and Its Relevance to Acetabular Migration

Goodman, Stuart B.; Adler, Sol; Fyhrie, David P.; Schurman, David J.

doi:10.1097/00003086-198811000-00026

Cited by 99 publications

(42 citation statements)

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“…LLD measurement was more accurate with the interteardrop line as a pelvic landmark instead of the ischial tuberosity because the teardrop has been described as a more consistent landmark less influenced by the position of the pelvis [16,58]. In patients with developmental dysplasia of the hip, the teardrop can be difficult to identify on an AP pelvic radiograph.…”

Section: Resultsmentioning

confidence: 99%

Preoperative Radiographic Assessment of Limb-length Discrepancy in Total Hip Arthroplasty

Meermans

Malik

Witt

et al. 2011

Clinical Orthopaedics &Amp; Related Research

149

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Background Pelvic radiographs are helpful in assessing limb-length discrepancy (LLD) before and after THA but are subject to variation. Different methods are used to determine LLDs. As a pelvic reference, both ischial tuberosities and the teardrops are used, and as a femoral reference, the lesser trochanter and center of the femoral head are used. Questions/purposes We validated the different methods for preoperative radiographic measurement of LLDs and evaluated their reliability. Patients and Methods LLDs were measured on full-leg radiographs for 52 patients (29 men, 23 women) with osteoarthritis (OA) of the hip and compared with different methods for measuring LLDs on AP radiographs of the pelvis. Results The true LLD varied from À8.0 to 9.1 mm. When the biischial line was used as a pelvic reference, the LLD measured on AP pelvis radiographs was different from the true LLD. No difference was found when the interteardrop line was used as a pelvic reference. There was substantial interobserver agreement when the lesser trochanter was used as a femoral reference (kappa = 0.66-0.70) and excellent interobserver and intraobserver agreement for all other measurements (kappa = 0.84-0.93). Conclusions Our data show use of the biischial line as a pelvic reference should be discouraged and the interteardrop line is a better alternative. The center of the femoral head is a more reliable femoral landmark compared with the lesser trochanter. Level of Evidence Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

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Section: Resultsmentioning

confidence: 99%

Preoperative Radiographic Assessment of Limb-length Discrepancy in Total Hip Arthroplasty

Meermans

Malik

Witt

et al. 2011

Clinical Orthopaedics &Amp; Related Research

149

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“…The inter-observer reliability of this method was tested by Woolson et al [25] and found to be high (0.5 mm) while the intra-observer reliability was tested by White and Dougall [24] and found to give a measurement error of ± 1 mm. Goodman et al [10] recommended the use of the teardrop points as a landmark Postop. clinical LLD measured in mm.…”

Section: Discussionmentioning

confidence: 99%

Leg length discrepancy in total hip arthroplasty: comparison of two methods of measurement

Sayed-Noor

Hugo

Sjödén

et al. 2008

International Orthopaedics (SICOT)

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Measurement of leg length discrepancy is an important part in planning a successful total hip arthroplasty (THA). Many clinical and radiological methods with variable degrees of accuracy have been advocated to carry out this measurement. We studied the accuracy of a commonly used clinical method by comparing it to a well-known and reliable radiological method. A total of 139 patients aged 44-89 (mean: 67.5 years) scheduled to undergo THA were examined for clinical and radiological leg length discrepancy measurements before and after the operation by the same observers. There was a poor correlation between the clinical and radiological methods preoperatively [r =0.21, intra-class correlation coefficient (ICC)=0.33]. The correlation was better postoperatively (r =0.45, ICC=0.62). The clinical method used is not recommended for leg length discrepancy measurement preoperatively. Caution should even be taken when using this method postoperatively. The authors recommend using the radiological method when measuring leg length discrepancy as a part of planning for THA.Résumé Objectif: La mesure de l'inégalité de longueur est une part importante de la planification des prothèses totales de hanche. De nombreuses méthodes cliniques et radiologiques ont été utilisées pour permettre de telles mesures. Nous avons voulu étudier une méthode clinique habituelle comparée à une méthode radiologique fiable. Patients et méthode: 139 patients âgés de 44 à 89 ans (en moyenne 67,5 ans) devant bénéficier d'une prothèse totale de hanche ont été examinés sur le plan clinique et radiologique avec mesure de l'inégalité de longueur avant et après l'intervention chirurgicale par les mêmes observateurs. Résultats: il y a peu de corrélations entre les méthodes cliniques et radiologiques pré-opératoires (r =0.21, ICC=0.33). La corrélation est bien meilleure en post-opératoire (r =0.45, ICC=0.62). En conclusion, la méthode clinique n'est pas recommandée en pré-opératoire, elle doit être utilisée avec méfiance. En post-opératoire il est recommandé d'utiliser une méthode radiologique afin de mesurer l'inégalité de longueur des membres inférieurs. Celle-ci doit faire partie du planning d'une prothèse totale de hanche.

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“…In addition, we measured the horizontal and vertical distances from an established point in the most distal aspect of the teardrop to the planned centre of rotation of the arthroplasty [5]. The teardrop was selected as a landmark to reference the horizontal and vertical position of the centre of rotation of the arthroplasty because it has proved to be the anatomical landmark least affected by pelvic tilt and rotation [13,16].…”

Section: Methodsmentioning

confidence: 99%

The utility and precision of analogue and digital preoperative planning for total hip arthroplasty

Valle

Comba

Taveras

et al. 2007

International Orthopaedics (SICO

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We prospectively compared the utility and precision of preoperative templating performed in printed films (analogue) with that performed on digital radiographs (digital) in 69 patients undergoing primary total hip replacement. Five patients were excluded when misplacement of the marker resulted in a magnification error greater that 10%; in the remaining patients (64 hips), the cup size was within ± one size in 62 (97%) of the analogue and 52 (81%) of the digital (p=0.01) plans. The stem size was within ± one size in 63 (98%) of the analogue and 60 (94%) of the digital (p=0.39) plans. The distance from the proximal corner of the lesser trochanter to the center of the prosthetic head (LTCD) in the analogue differed by 5 mm or more from the digital plan in nine cases (14%). Analogue preoperative planning yielded more predictable results than digital planning, particularly in terms of acetabular component size and LTCD that dictates limb lengtheningshortening. The sources of error were not clearly explained by variations in magnification. Inconsistent positioning of the magnification marker may jeopardise the safe implementation of digital templating.Résumé Nous avons, de façon prospective, comparé l'utilité et la précision de la planification préopératoire réalisée sur des films radiologiques classiques ou sur des radiographies numérisées sur 69 patients devant bénéficier d'une prothèse totale de hanche. 5 patients ont été exclus car il existait une erreur de plus de 10% sur le coefficient d'agrandissement et sur les 64 hanches restantes, la taille prévue de la cupule correspondant dans 97% des cas (62 hanches) sur les films classiques et dans 81% des cas (52 hanches) sur les films numérisés. La taille de la pièce fémorale était celle prévue dans 98% des cas (63 hanches) sur les films classiques, dans 94% des cas (60 hanches) sur les films numérisés. La distance entre bord proximal du petit trochanter et la tête prothétique (LTCD) sur les films classiques, n'a pas montré de différence de plus de 5 millimètres. Cette distance était supérieure dans 9 cas (14%) sur les films numérisés. Une planification pré opératoire est beaucoup plus fiable sur les films classiques que sur les films numérisés, particulièrement en ce qui concerne la taille du composant acétabulaire et les problèmes d'inégalité de longueurs. Les sources d'erreur ne sont pas très clairement expliquées par les modifications du taux d'agrandissement, la planification sur des clichés numérisés peut être source d'erreur.

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The Acetabular Teardrop and Its Relevance to Acetabular Migration

Cited by 99 publications

References 0 publications

Preoperative Radiographic Assessment of Limb-length Discrepancy in Total Hip Arthroplasty

Preoperative Radiographic Assessment of Limb-length Discrepancy in Total Hip Arthroplasty

Leg length discrepancy in total hip arthroplasty: comparison of two methods of measurement

The utility and precision of analogue and digital preoperative planning for total hip arthroplasty

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