Minimally invasive computer-navigated total hip arthroplasty, following the concept of femur first and combined anteversion: design of a blinded randomized controlled trial

Clinical Orthopaedics &Amp; Related Research

Woerner

Messmer

et al. 2017

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Background Iliopsoas tendon impingement is one possible reason for persistent groin pain and diminished functional outcome after THA. So far, estimation by eye and palpation is the standard procedure to intraoperatively assess the distance of the cup to the anterior rim. However, novel technologies such as imageless navigation enable intraoperative measurements of the cup in relation to the psoas tendon and bony landmarks. Questions/purposes We asked whether psoas impingement (1) can be reduced using imageless navigation compared with the standard technique and (2) is associated with specific patient characteristics. Furthermore, we investigated (3) if anterior cup protrusion (overhang) is associated with lower outcome scores for pain and function.Methods The current study is a reanalysis of data from a randomized controlled trial evaluating navigation for THA; 135 patients were randomized for surgery with or without the use of imageless navigation. The risk for anterior protrusion of the cup above the acetabular rim and thus potential psoas impingement, defined as an overhang of the cup above the anterior acetabular rim as measured on postoperative CT, was either controlled with the help of navigation or standard control by eye and palpation intraoperatively. Postoperatively, the anterior protrusion of the cup above the acetabular rim was measured on three-dimensional (3-D) CT by a blinded, external institute. In addition to patient-related outcome measures, the Harris hip score, Hip disability and Osteoarthritis Outcome Score, and EuroQol were obtained 1 year postoperatively. Altogether 123 data sets were available for primary analysis and 115 were available for 1-year followup. Results There was no difference, with the numbers available, between the navigated and the control groups in terms of the mean distance of the cup below the anterosuperior acetabular rim (3.9 mm; À5.3 to 12.6 mm versus 4.4 mm; À7.9 to 13.7 mm; p = 0.72) or the anteroinferior acetabular rim (4.7 mm; À6.2 to 14.8 mm versus 4.2 mm; À7.1 to 16.3 mm; p = 0.29). There was no difference, with the numbers available, in terms of the proportion of cups with anterior overhang (7%, four of 57 versus, 15%, 10 of 66; p = 0.16), respectively. After controlling for potential confounding variables such as cup inclination, cup size, patient age, BMI, stage of arthritis, and length of skin incision, we found cup anteversion (hazard ratio [HR], 0.87; 95% CI, 0.81-0.93; p \ 0.001) and female sex (HR, 3.88; 95% CI, 1.01-14.93; p = 0.049) were associated with a propensity to potential psoas impingement. With the numbers available, there were no differences observed in

Section: Methodsmentioning

confidence: 99%

Navigation is Equal to Estimation by Eye and Palpation in Preventing Psoas Impingement in THA

Clinical Orthopaedics &Amp; Related Research

Woerner

Messmer

et al. 2017

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“…The influence of this parameter can, therefore, not be determined and will be a focus of a future study. 20 The proposed methods in this article are aimed at defining two functional outcomes of THR that are related to wear and rim loading. One important cause for the long term failure of a hip prosthesis is the excessive accumulation of wear debris, 39,40 which can induce an osteolytic reaction, leading to component loosening and implant failure.…”

Section: Discussionmentioning

confidence: 99%

“…The protocol of a future study includes a knee bend motion that servers as an approach for those critical motions. 20 It also includes a corresponding preoperative gait analysis, by which means one may be able to determine a possible relationship between pre-and post-operative wear rates. This may open the door to be one day able to predict occurring wear rates by means of a pre-operative gait analysis.…”

Section: Discussionmentioning

confidence: 99%

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Measuring functional outcome after total hip replacement with subject-specific hip joint loading

Dendorfer

Dullien

et al. 2012

Proc Inst Mech Eng H

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Total hip replacement is an often-performed orthopedic surgical procedure; the amount of procedures undertaken will increase since our life expectancy is growing. In order to optimize function, hip biomechanics should be restored to as near normal as possible. The goal of this pilot study was to determine whether or not it is feasible to compute the vectorial hip reaction force pathways on the head of the prosthesis and the force angles relative to the cup of the prosthesis that occur during gait in total hip replacement patients, serving as an objective measurement of the functional outcome following hip replacement.A three-dimensional gait analysis, measuring ground reaction forces and kinematics, was performed. The data retrieved from the gait analysis was used as the input for the musculoskeletal model to compute vectorial joint reaction forces for data processing. To evaluate the position and orientation of the joint reaction forces, the force path, as well as the force angles for the operated and non-operated joint, has been calculated during the stance phase of the specific leg.The force path for subject 2 on the non-operated side is only located in the posterior-lateral quarter, as is the force path for subject 1. In contrast to this subject, the force path for subject 2 at the operated hip joint can be found only within the anterior quarter of the head of the implant, where it is nearly equally distributed in the medio-lateral half of the prosthesis head. The force-inclination angles on the cup of subject 1, with respect to the plane of the socket face, indicates that the force vector is mainly positioned in the same quadrant when compared with subject 2 (in a cup-fixed coordinate system). The force-anteversion angle behaves similarly to the force-inclination angle, even when the effects are not as pronounced.The proposed methods in this article are aiming to define two functional outcomes of total hip replacement that are related to wear and rim loading. It is accepted that wear is not only a function of time, but a function of use. Owing to the methods listed in this article, we are able to determine a) the applied force and b) the sliding distance (force pathway) in a subject-specific manner. The computed hip-reaction force angles and the distance to the rim cup are a measurement for cup or rim loading, and occurs in the so-called safe-zones. This method may well give us insight into the biomechanical situation during gait, after receiving total hip replacement, that we need to fully understand the mechanisms acting on a hip joint and to prove a possible increase of functional outcome after receiving total hip replacement.

“…All procedures were in accordance with the ethical standards of the responsible committee on human experimentation and with the Helsinki Declaration of 1975, as revised in 2000. The current study is a secondary analysis of a larger project [14]. The primary outcome of this larger study was to assess whether the ROM of the prosthetic joint could be improved by computerassisted functional optimization of the position and containment of the acetabular component.…”

mentioning

confidence: 99%

Digital Planning Software Fails to Reflect Stem Torsion on Plain Radiographs after Total Hip Arthroplasty

Worlicek

Zeman

et al. 2016

Fortschr Röntgenstr

Purpose: The purpose of this study was to evaluate the validity of commercially available planning software on plain radiographs after THA compared to CT scans as the gold standard. Patients and Methods: In a prospective clinical study, anteroposterior (AP) radiographs and three-dimensional CT scans (3D-CT) were obtained for 121 patients, who underwent minimally invasive, cementless THA with a straight tapered stem, in a lateral decubitus position. For measuring SV, we used digital planning software (TraumaCad 2.0, BrainLAB Feldkirchen, Germany). Two independent raters repeated the analysis after a six-week interval. Radiological measurements were compared with 3D-CT measurements by an independent, blinded external institute. This investigation was approved by the local ethics commission (no.?10?-121-?0263) and is a secondary analysis of a larger project (DRKS00?000?739, German Clinical Trials Register May-02???2011). Results: The radiograph measurements showed very high intra- and interrater agreement. The intra-class correlation (ICC) of the intrarater agreement was 0.97 for rater 1 and 0.98 for rater 2. The intrarater reliability was 0.99 using the mean values of both rater measurements. The mean difference between the average radiograph measurement and the 3D-CT-based measurement was 0.41? (SD 11.24?) (range: ?33.85??22.50?; 95?% limits of agreement: ?21.63???22.45), but there was no correlation found between both methods. Conclusion: Measuring stem version with the help of commercially available digital planning software on plain radiographs after THA has high intra- and interrater reliability but clinically inacceptable validity and reliability when compared to 3D-CT scans. Key Points: ??Measuring stem torsion after THA on plain radiographs with digital planning software is not valid. Citation Format: ??Worlicek M, Weber M, Zeman F et?al. Digital Planning Software Fails to Reflect Stem Torsion on Plain Radiographs after Total Hip Arthroplasty. Fortschr R?ntgenstr 2016; 188: 763???767