The Position of the Bipolar Cup Reflects the Direction of the Hip Contact Force Acting on It

Lee, Mel S.; Chen, Alvin C.Y.; Chen, Kuo; Tai, Ching‐Lung; Senan, Vinesh; Shih, Chun–Hsiung

doi:10.1016/j.arth.2006.02.079

Cited by 5 publications

(3 citation statements)

References 28 publications

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“…The goal was to bring the fracture line perpendicular to the direction of the joint reaction force, which was around 16 degrees in the frontal plane according to a previous study. [10] The shearing force at the fracture site could therefore be converted to a compression force during weightbearing. The osteotomy was of a staggered shape with asymmetrical limbs, the short limb being closer to the lateral side in order to preserve more bone on the lateral wall for secure xation of the DHS.…”

Section: Surgical Proceduresmentioning

confidence: 99%

Valgus Intertrochanteric Osteotomy for Salvage of Failed Femoral Cervicotrochanteric Fracture Fixation

Odeh¹,

et al. 2020

Preprint

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BackgroundFemoral cervicotrochanteric fracture fixation failure often requires a salvage procedure to preserve the hip. To understand its limitations, this study investigated the use of intertrochanteric osteotomy for this purpose and analyzed causes of failure.MethodsDuring 2001 − 2017, 21 patients (males:females = 12:9; 47 ± 17 years) with failed femur cervicotrochanteric fracture fixation were treated with intertrochanteric osteotomy. All patients were followed-up using functional assessment according to the Harris hip score (HHS) and radiological assessment. The clinical end-point was conversion to hip arthroplasty for any reason or acquiring a symptomatic hip with a HHS < 80.ResultsWith a follow-up duration of 124 ± 63 months, success was achieved in 16 patients, whereas 5 patients developed fixation failure. Early failure was associated with fixation loss in 2 hips with subcapital fractures, while late failure was related to progression of pre-existing osteonecrosis of the femoral head (ONFH) in 3 hips. Aside from the 2 early failure hips, the osteotomy healed uneventfully in all cases, and the original fracture sites healed within 17.2 ± 6.3 weeks. Of the 5 hips converted to arthroplasty, standard femoral implants were used without the need to re-perform an osteotomy to align the medullary canal. At the final follow-up, significant improvements in limb-length discrepancy (LLD), neck-shaft angle (NSA), and HHS were observed. The valgus osteotomy angle for correction was 21.9° ± 8.4°, and this was maintained at 21.1° ± 10.5° during follow-up.ConclusionsIntertrochanteric osteotomy is a useful operation and can promote fracture-healing in cases of failed cervicotrochanteric fracture fixation. Subcapital fracture with limited bone to enable secure purchase of the fixation device and pre-existing ONFH were associated with high failure rates. In such cases, salvage should not be attempted using this procedure alone, and arthroplasty or other salvage procedures may be necessary.

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Section: Surgical Proceduresmentioning

confidence: 99%

Valgus Intertrochanteric Osteotomy for Salvage of Failed Femoral Cervicotrochanteric Fracture Fixation

Odeh¹,

et al. 2020

Preprint

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“…They recorded a decrease in bipolar cup angle along the investigation period, so the study underlines the long time effect of the self centering mechanism. Based on these measurements, a 16 degrees loading angle in frontal plane was determined [3].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Aspects of Self-Alignment Mechanism in Hip Bipolar Hemiarthroplasty

Stoia

Vigaru

Rusu

et al. 2017

KEM

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The paper proposes a mechanical study of the self-centering mechanism of the bipolar prosthesis. This represents the fundamental principle of the bipolar construction, and relays on the offset between the inner and outer center of rotations of the bipolar head. In the paper, the kinematical aspects of the construction were recorded and explained by using five different offset values and keeping constant the femoral head diameter and the acetabular diameter. The simulations were conducted by imposing to the femoral head a linear movement in the vertical direction, similar to a reaction force that occurs when an implanted patient stands up. Two initial conditions were used for each geometric offset: one ideal, no friction and another more realistic by implementing friction coefficients at the sliding interfaces.

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“…In case of bipolar HA, it has been shown that the cup rotates to a relatively constant horizontal position after weight bearing, which is attributed to the overall effect of different factors such as joint geometry, muscle action, soft tissue, and metal-on-bone friction [ 4 , 16 , 17 ]. Even though the importance of this balanced position for the clinical outcome remains unclear, it might be possible that arthritic changes of the acetabulum, with central osteophytes in particular, result in an aberrance of the head position and lead to restricted range of motion or hip pain [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

The value of modular hemiarthroplasty for unstable femoral neck fractures in elderly patients with coxarthrosis

Döring

Jentzsch

Scheyerer

et al. 2016

BMC Musculoskelet Disord

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BackgroundDisplaced femoral neck fractures are common in the elderly patient. The surgical treatment options consist of a hemiarthroplasty (HA) or total hip arthroplasty (THA). However, the best surgical choice is still under debate. Bipolar HAs do not address preexisting arthritic changes of the acetabulum, which may lead to an unfavorable clinical outcome. The purpose of the present study was to conduct a long term follow-up analysis of the bipolar hemiarthroplasty with particular focus on the influence of preoperative acetabular osteoarthritis on the functional outcome.MethodsIn a retrospective observational study, the medical charts of consecutive patients treated with a bipolar hemiarthroplasty at a level one trauma center between 2004 and 2008 were reviewed before a final radiographic and clinical follow-up was performed. The outcome variables consisted of arthritic findings on the pre- and postoperative x-rays with particular focus on double fond osteophyte (DFO) and posterior wall sign (PWS) as well as the revision rate and functional scores.ResultsThis study included 102 patients with a mean age of 77.2 years. Most patients (75 %) had a Kellgren-Lawrence grading scale (KLGS) of 2 or 3. While only 30 % of patients had a DFO, most patients (73 %) had a PWS. The DFO correlated significantly with the KLGS, but no correlation was seen with the clinical outcome. Most patients showed a decreased offset by a mean of −7.8 mm. The mean modified Harris Hip Score (HHS) of 90.3 and the mean Merle d'Aubigné score of 10.8 correlated significantly. Despite a significant correlation of the HSS subcategory of pain and the preoperative KLGS, there was no statistical relationship between the arthritic x-ray measurements and the clinical outcome.ConclusionsIn the presented study population, the presence of radiographic acetabular osteoarthritis did not influence the clinical outcome after bipolar hemiarthroplasty for displaced femoral neck fractures.

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The Position of the Bipolar Cup Reflects the Direction of the Hip Contact Force Acting on It

Cited by 5 publications

References 28 publications

Valgus Intertrochanteric Osteotomy for Salvage of Failed Femoral Cervicotrochanteric Fracture Fixation

Valgus Intertrochanteric Osteotomy for Salvage of Failed Femoral Cervicotrochanteric Fracture Fixation

Mechanical Aspects of Self-Alignment Mechanism in Hip Bipolar Hemiarthroplasty

The value of modular hemiarthroplasty for unstable femoral neck fractures in elderly patients with coxarthrosis

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