Novel measurement method on plain radiographs to predict postoperative stem anteversion in cementless THA

Weber, Markus; Messmer, Benedikt; Woerner, Michael; Grifka, Joachim; Renkawitz, Tobias

doi:10.1002/jor.23202

Cited by 6 publications

(5 citation statements)

References 23 publications

(23 reference statements)

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“…Intraoperative fluoroscopy was used to control the size as well as the "best fitting" position of the broach regarding flexion and torsion of the femur according to two radiographic planes. The stem was inserted in the most stable position predefined by the patient-individual anatomy 15 . According to the patient's individual anatomic situation offset was restored by using either a stem with a standard offset or a stem with a high offset geometry (HO).…”

Section: Methodsmentioning

confidence: 99%

Inaccurate offset restoration in total hip arthroplasty results in reduced range of motion

Weber

Merle

Nawabi

et al. 2020

Sci Rep

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Offset restoration in total hip arthroplasty (THA) is associated with postoperative range of motion (ROM) and gait kinematics. We aimed to research into the impact of high offset (HO) and standard stems on postoperative ROM. 121 patients received cementless THA through a minimally-invasive anterolateral approach. A 360° hip ROM analysis software calculated impingement-free hip movement based on postoperative 3D-CTs compared to ROM values necessary for activities of daily living (ADL). The same model was then run a second time after changing the stem geometry between standard and HO configuration with the implants in the same position. HO stems showed higher ROM for all directions between 4.6 and 8.9° (p < 0.001) compared with standard stems but with high interindividual variability. In the subgroup with HO stems for intraoperative offset restoration, the increase in ROM was even higher for all ROM directions with values between 6.1 and 14.4° (p < 0.001) compared to offset underrestoration with standard stems. Avoiding offset underrestoration resulted in a higher amount of patients of over 20% for each ROM direction that fulfilled the criteria for ADL (p < 0.001). In contrast, in patients with standard stems for offset restoration ROM did increase but not clinically relevant by offset overcorrection for all directions between 3.1 and 6.1° (p < 0.001). Offset overcorrection by replacing standard with HO stems improved ROM for ADL in a low number of patients below 10% (p > 0.03). Patient-individual restoration of offset is crucial for free ROM in THA. Both over and underrestoration of offset should be avoided. Although total hip arthroplasty (THA) is a highly successful treatment option for end-stage osteoarthritis with a positive responder rate of over 90% 1, the surgeon is faced with high patients' expectations regarding the functional capacity of the artificial hip joint. Beside a correct intraoperative orientation of both cup and stem, restoration of biomechanics such as offset is crucial for optimal function and long-term outcome after THA 2-4. Failure of correct offset restoration is associated with impingement, reduced hip abductor strength, altered gait kinematics and even higher wear of the artificial hip joint 5-8. To address the interindividual variability of the femoral anatomy, most modern implant systems offer at least two different offset geometries of the femoral stem-a standard offset design and a high offset design 9. Prior to surgery the biomechanical restoration of offset is usually templated on radiographs illustrating the preferred stem design for the respective patient. However, intraoperative alterations in relation to the preoperative plan or reduced joint stability harbour the potential to complicate the right choice of femoral offset design during THA. The discussion of correlation between high offset (HO) stems and higher range of motion (ROM) is controversial in literature. Although aiming to find the balance between the risks of impingement due to offset reduction on the one hand and po...

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Section: Methodsmentioning

confidence: 99%

Inaccurate offset restoration in total hip arthroplasty results in reduced range of motion

Weber

Merle

Nawabi

et al. 2020

Sci Rep

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“…Manual CT segmentation was performed on the pelvic bone and on the metal acetabular and femoral components by an independent external institute (Fraunhofer MEVIS, Bremen, Germany), blinded to individual patient data. Cup inclination, anteversion, and stem antetorsion were evaluated by the independent external institute on the manually segmented reconstruction of the pelvis and femur using image-processing software (based on MeVisLab, MeVis, Bremen, Germany), as previously described [ 10 , 11 , 12 , 13 , 14 ]. Based on the manually segmented bone models, the postoperative ROM was calculated using a previously evaluated algorithm that automatically determines single prosthetic or combined bony and prosthetic impingement by virtually moving the leg until a collision between the 3D objects occurs [ 13 , 15 ].…”

Section: Methodsmentioning

confidence: 99%

Which Safe Zone Is Safe in Total Hip Arthroplasty? The Effect of Bony Impingement

Weber

Kunow

Innmann

et al. 2022

JPM

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“Safe zones” for cup position are currently being investigated in total hip arthroplasty (THA). This study aimed to evaluate the impact of bony impingement on the safe zone and provide recommendations for cup position in THA. CT scans were performed on 123 patients who underwent a cementless THA. Using the implant data and bone morphology from the CT scans, an impingement detection algorithm simulating range of motion (ROM) determined the presence of prosthetic and/or bony impingement. An impingement-free zone of motion was determined for each patient. These zones were then compared across all patients to establish an optimized impingement-free “safe zone”. Bony impingement reduced the impingement-free zone of motion in 49.6% (61/123) of patients. A mean reduction of 23.4% in safe zone size was observed in relation to periprosthetic impingement. The superposition of the safe zones showed the highest probability of impingement-free ROM with cup position angles within 40–50° of inclination and 20–30° of anteversion in relation to the applied cup and stem design of this study. Virtual ROM simulations identified bony impingement at the anterosuperior acetabular rim for internal rotation at 90° of flexion and at the posteroinferior rim for adduction as the main reasons for bony impingement.

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“…The PFV of an uncemented femoral stem is partly dictated by the stem design and the highly variable internal morphology of the proximal femur [ 27 ]. Consequently, the final stem position is a compromise of best-fitting a straight stem down to the proximal femur, leaving the surgeon with minimal control over the PFV [ 23 , 28 , 29 ]. Contrastingly, in cemented femoral stems, the surgeon can intra-operatively adjust the version of the femoral stem to a desired position within the variable thickness of the cement mantle [ 17 , 30 , 31 ].…”

Section: Introductionmentioning

confidence: 99%

Cemented or uncemented fixation: Which allows a more acceptable prosthetic femoral version in total hip arthroplasty?

Moralidou,

Di Laura,

Hothi

et al. 2023

J Orthop Surg Res

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Background Three-dimensional computed-tomography (3D-CT) planning for primary Total Hip Arthroplasty (THA) typically uses the external femoral surface; as a result, it is difficult to predict the prosthetic femoral version (PFV) for uncemented femoral stems that press-fit to the internal surface of the bone. Cemented fixation allows the surgeon to adjust the version independent of the internal femoral anatomy. We aimed to better understand the effect of the fixation type on PFV. Methods This was a case series study including a total of 95 consecutive patients (106 hips), who underwent uncemented (n = 81 hips) and cemented (n = 25 hips) primary THA using the posterior approach. The surgeon aimed for a PFV of 20°. Our primary objective was to compare PFV in both groups; our secondary objective was to evaluate the clinical outcomes. Results The mean (± SD) PFV was 13° (± 9°) and 23° (± 8°) for the uncemented and cemented THA groups (P < 0.001), respectively. In the uncemented THA group, 36% of the patients had a PFV of < 10°. In the cemented THA group, this clinically important threshold dropped to 8%. Similarly, the Bland–Altman (BA) plots showed wider 95% limits of agreement for the uncemented group. Satisfactory clinical outcomes were recorded. Conclusion We found that the PFV was more clinically acceptable, for the posterior surgical approach, in the cemented group when compared to the uncemented group. Both THA groups reported high variability indicating the need to develop surgical tools to guide the PFV closer to the surgical target.

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Novel measurement method on plain radiographs to predict postoperative stem anteversion in cementless THA

Cited by 6 publications

References 23 publications

Inaccurate offset restoration in total hip arthroplasty results in reduced range of motion

Inaccurate offset restoration in total hip arthroplasty results in reduced range of motion

Which Safe Zone Is Safe in Total Hip Arthroplasty? The Effect of Bony Impingement

Cemented or uncemented fixation: Which allows a more acceptable prosthetic femoral version in total hip arthroplasty?

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