Cup Position Alone Does Not Predict Risk of Dislocation After Hip Arthroplasty

doi:10.1016/j.arth.2014.07.009

The Journal of Arthroplasty

Volume 30, Issue 1, January 2015, Pages 109-113

https://doi.org/10.1016/j.arth.2014.07.009 Get rights and content

Abstract

We used a large prospective institutional registry to determine if there is a ‘safe zone’ that exists for acetabular component position within which the risk of hip dislocation is low and if other patient and implant factors affect the risk of hip dislocation. Patients who reported a dislocation event within six months after hip arthroplasty surgery were identified, and acetabular component position was measured with anteroposterior radiographs. The frequency of dislocation was 2.1% (147 of 7040 patients). No significant difference was found in the number of dislocated hips among the radiographic zones (± 5°, ± 10°, ± 15° boundaries). Dislocators < 50 years old were less active preoperatively than nondislocators (P = 0.006). Acetabular component position alone is not protective against instability.

Section snippets

Patients and Methods

From 2007 to 2012, 19,449 patients (22,097 hip procedures) were recorded in an IRB-approved prospective total joint arthroplasty registry. All patients who underwent primary THA were prospectively enrolled, of which 9107 patients consented to participate in the registry. Baseline measurements of patient demographics, preoperative health status, medical comorbidities, and clinical outcome measurements were collected. An adverse event report questionnaire was mailed to all consented patients six

Results

The frequency of dislocation over the six months following primary THA was 2.1% (147 of 7040 patients). The quality of matching patients was high, with all imbalances well below 0.2 (Table 2). No difference was found in acetabular inclination (P = 0.42) or anteversion (P = 0.50) angles between dislocators and nondislocators (Fig. 1). Differences in inclination and anteversion between matched patients were inconsistent (Fig. 2). Hips that went on to dislocate were found in all zones (even zones with ±

Discussion

Hip dislocation is a distressing event for patients and surgeons, and prevention has been studied for as long as THAs have been performed [22]. The orthopedic community generally accepts that malposition of the acetabular component outside of a ‘safe zone’ contributes to dislocation, since the orientation of THA components directly impacts the arc of motion and therefore the likelihood of impingement. To reduce the risk of dislocation, a ‘safe zone’ was defined in previous small cohort studies

Acknowledgments

This study utilized an implant registry developed with funding from the Agency for Healthcare Research and Quality through a Center for Education and Research on Therapeutics grant (CERTs; Agency of Health Research and QualityRFA-HS-05-14). Research reported in this publication was also supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number AR007281. The content is solely the responsibility of the authors

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Safe Sex After Total Hip Arthroplasty: Using Computed Tomography-Based Robotics to Evaluate “At-Risk” Sexual Positions
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Total hip arthroplasty (THA) can improve sexual satisfaction, but fear of dislocation can lead to sexual difficulties following this procedure. Previous kinematic research identified 4 sexual positions in women and 2 in men that were considered at risk for impingement. This study aimed to validate these findings using current robotic THA simulations.
The 3-dimensional renderings from 12 patients who received computed tomography (CT)-based robotic THA were used to assess for prosthetic and/or bony impingement among 12 popular sexual positions. There were 9 cup orientations tested for each position (a combination of anteversion [0 °, 15 °, and 30 °] and inclination [40 °, 45 °, and 60 °]). The at-risk positions were tested again using the unique hip positions and cup orientations where previous geometric modeling data found impingement to occur.
Using mean hip positions, impingement occurred in at least 1 patient in 1 of the 12 positions for women (position 5) and 5 of the 12 positions for men (positions 1, 5, 8, 10, and 11). Among the at-risk positions, impingement occurred in none of the 2 at-risk women positions (0 of 17 cup orientations) and in both at-risk men positions (9 of 9 cup orientations for position 8 and 1 of 1 for position 11).
Recreating popular and at-risk sexual positions following THA with a CT-based robotics system yielded results that were inconsistent with previous geometric modeling data. Resolving these discrepancies is crucial for surgeons to provide accurate postoperative patient education. The CT-based robotic systems may provide necessary input to feasibly individualize such recommendations, but current limitations in CT-based robotics require continued attention and innovation.
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Complication Rate After Primary Total Hip Arthroplasty Using the Posterior Approach and Enabling Technology: A Consecutive Series of 2,888 Hips
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Total hip arthroplasty (THA) is a safe and effective procedure; however, complications such as dislocation, fracture, and infection still occur. It is still unclear whether the dislocation rate via the posterior approach (PA) is better, equal, or worse than the direct anterior approach. Our aim was to report the primary THA dislocation rate via the PA using enabling technology in a large consecutive series of patients.
A retrospective cohort of 2,888 primary THAs were reviewed at a single, high-volume, academic institution from January 2018 to September 2021. All patients underwent a THA by 4 fellowship-trained orthopaedic surgeons through the PA with enabling technology. Overall dislocation and readmission rates within 90 days and up to 3 years were analyzed.
Of the 2,888 procedures, a total of 39 patients had complications related to the surgery during the 3-year follow-up period. There were 10 patients (0.35%) who experienced a dislocation, with half undergoing surgical revision. Of the 39 patients who experienced complications, 37 (1.3%) were readmitted and 2 underwent revision during their hospital stay. Postoperative periprosthetic fractures were the most common cause for readmission and reoperation at a rate of 0.52% and 0.52%, respectively.
The dislocation rate of 0.35% is one of the lowest reported rates via the PA at a mean follow up of 2.1 years and is comparable to previously published rates using alternate approaches. Using contemporary THA with enabling technology, the PA is a reliable approach with respect to dislocation and complication rates after primary THA.
Does Individualization of Cup Position Affect Prosthetic or Bone Impingement Following Total Hip Arthroplasty?
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Spinopelvic (SP) mobility patterns during postural changes affect three-dimensional acetabular component position, the incidence of prosthetic impingement, and total hip arthroplasty (THA) instability. Surgeons have commonly placed the acetabular component in a similar “safe zone” for most patients. Our purpose was to determine the incidence of bone and prosthetic impingement with various cup orientations and determine if a preoperative SP analysis with individualized cup orientation lessens impingement.
A preoperative SP evaluation of 78 THA subjects was performed. Data were analyzed using a software program to determine the prevalence of prosthetic and bone impingement with a patient individualized cup orientation versus 6 commonly selected cup orientations. Impingement was correlated with known SP risk factors for dislocation.
Prosthetic impingement was least with the individualized choice of cup position (9%) versus preselected cup positions (18%-61%). The presence of bone impingement (33%) was similar in all groups and not affected by cup position. Factors associated with impingement in flexion were age, lumbar flexion, pelvic tilt (stand to flexed seated), and functional femoral stem anteversion. Risk factors in extension included standing pelvic tilt, standing SP tilt, lumbar flexion, pelvic rotation (supine to stand and stand to flexed seated), and functional femoral stem anteversion.
Prosthetic impingement is reduced with individualized cup positioning based on SP mobility patterns. Bone impingement occurred in one-third of patients and is a noteworthy consideration in preoperative THA planning. Known SP risk factors for THA instability correlated with the presence of prosthetic impingement in both flexion and extension.
Relationship between perceived and structural leg length discrepancies of patients with hip osteoarthritis dysplasia
2023, Orthopaedics and Traumatology: Surgery and Research
Only few studies have been conducted on leg length discrepancy (LLD) in patients with hip osteoarthritis (OA). This study aimed to examine the relationship between perceived LLD (pLLD) and structural LLD (sLLD) in patients with advanced OA and to determine the factors influencing both LLDs. This retrospective study aimed to answer the following questions: (1) are older adults less likely to perceive LLD than younger adults? (2) is there a relationship between pLLD and sLLD? and (3) is pLLD associated with patient satisfaction?
We hypothesized that older adults are less likely to perceive LLD than younger adults.
We recruited 125 patients (102 women and 23 men) with hip OA associated with developmental dysplasia of the hip defined as grade 3 or higher according to the Tönnis classification and excluding contralateral grade 2 or higher. The mean age of the patients was 65.2 ± 11.2 (36–85) years. Before surgery, 2-mm and 5-mm thick plates were placed on the floor on the plantar surface of the short leg to measure pLLD. Preoperative computed tomography (CT) was performed and sLLDs were measured using the 3D planning software ZedHip. The following associated factors were evaluated: age, height, weight, body mass index (BMI), adduction and abduction range of motion (ROM) of the affected hip joint, Crowe classification, standing pelvic inclination in the coronal plane, Cobb angle and Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ).
The absolute difference between pLLD and sLLD was modestly positively correlated with age (R = 0.206; p < 0.05) indicating older patients were less prone to perceive LLD. A strong positive correlation was found between pLLD (4.8 ± 7.3 mm; range: -37 to 28 mm) and sLLD (6.4 ± 7.0 mm; range: -29.9 to 23.7 mm) (R = 0.714, p < 0.05). The greater the pLLD, the smaller the hip abduction ROM (24.8 ± 11.6°; range: 0 to 45°) tended to be, while the greater the sLLD, the smaller the hip abduction and adduction ROM (10.3 ± 5.7°; range: 0 to 25°) tended to be (R= -0.259 and R= -0.297, respectively; p < 0.05) The clinical significance of this finding is that pLLD may be improved if hip ROM training is performed before surgery. pLLD was significantly smaller in the group without pelvic inclination (8.0 ± 14.1 mm; range: -37 to 22 mm) than in the group with pelvic inclination to the affected side (6.9 ± 7.5 mm; range: -12 to 28 mm) and in the group with no inclination to the affected side (7.3 ± 7.6 mm; range: -8 to 25 mm) (p < 0.05) The clinical significance of this finding is that improving pelvic inclination with hip ROM training or muscle stretching may also reduce pLLD. No significant differences were noted between pLLD and JHEQ total scores or subgroups.
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IV; case control study.

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: The Conflict of Interest statement associated with this article can be found at http://dx.doi.org/10.1016/j.arth.2014.07.009.

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Cup Position Alone Does Not Predict Risk of Dislocation After Hip Arthroplasty

Abstract

Section snippets

Patients and Methods

Results

Discussion

Acknowledgments

J Arthroplasty

J Arthroplasty

J Biomech

Orthop Traumatol Surg Res

J Clin Epidemiol

J Arthroplasty

The epidemiology of revision total hip arthroplasty in the United States

J Bone Joint Surg

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