Acetabular Component Position and the Risk of Dislocation Following Primary and Revision Total Hip Arthroplasty: A Matched Cohort Analysis

Sadhu, Anita; Nam, Denis; Coobs, Benjamin R.; Barrack, Toby; Nunley, Ryan M.; Barrack, Robert L.

doi:10.1016/j.arth.2016.08.008

Cited by 84 publications

(54 citation statements)

References 23 publications

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“…19 While some studies have suggested that acetabular component remains an important component of prosthetic joint stability, others have emphasized that a large number of primary hips become unstable when acetabular components are placed within the traditional safe zone. 9,23 Abdel et al reported that 65 percent of unstable primary total hip replacements performed with a posterior approach were positioned inside of the safe zone. 24 Opperer et al reported that dislocations occurred when acetabular components were well positioned in 88.7% of their cases.…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have supported lower dislocation risks among patients when optimal acetabular component alignment has been achieved. 1,22,23 But the importance of the traditional Lewinnek acetabular safe zone has been challenged by other studies that have not associated primary THA dislocation events with acetabular component malposition. 3,4,11,24,25 The ability to define specific surgical factors contributing to dislocation risk has been limited by relatively small and heterogeneous patient cohorts, and the relative role of insufficient femoral length or offset on THA instability has not been confirmed in the literature.…”

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confidence: 99%

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Relative Contribution of Acetabular and Femoral Reconstruction to Prosthetic Joint Instability Risk after Primary Total Hip Arthroplasty

et al. 2019

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Prosthetic joint instability is a challenging concern for a minority of total hip arthroplasty (THA) patients. Placement of the acetabular component within the traditional safe zone does not eliminate dislocation, and the relative contribution of femoral length and offset to instability risk has not been well defined. The authors compared 53 dislocated primary THAs treated against an age- and gender-matched cohort of 134 stable primary THAs. Anteroposterior and cross-table lateral radiographs were used to determine whether reconstructions met targets for acetabular inclination (30–50 degrees), acetabular anteversion (5–30 degrees), femoral length (0–9.9 mm) and femoral offset (0–9.9 mm). Statistical analysis was performed to assess univariate and multivariate relationships with an instability event; statistical significance was set using a two-sided p-value < 0.05. Forty-seven (88.7%) of the dislocating hips had nonoptimal acetabular or femoral reconstructions. While a similar proportion of patients in the study and control groups had acetabular reconstruction within the safe zone (51.5 vs. 47.2%, p = 0.63) patients with unstable hips were more likely to have acetabular component inclination outside of the target zone (30.2 vs. 7.5%, p < 0.01), acetabular anteversion < 15 degrees (30.2 vs. 3.7%, p < 0.0001), reduced femoral length (35.9 vs. 3.7%, p < 0.0001), and reduced femoral offset (41.5 vs. 7.46%, p < 0.0001). Stepwise multivariate logistic regression was performed and identified femoral head size less than 32 mm (OR 2.9, 95% CI 1.4–6.2) and higher inclination angle (OR 1.1, 95% CI 1.04–1.2) as significant independent risk factors for hip instability. The authors' study findings suggest that insufficient acetabular anteversion, femoral length, and femoral offset reconstruction contribute significantly to instability risk following THA. Using a larger femoral head is protective, but should be balanced against long-term volumetric wear risk.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Relative Contribution of Acetabular and Femoral Reconstruction to Prosthetic Joint Instability Risk after Primary Total Hip Arthroplasty

et al. 2019

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“…Dislocation rates are demonstrably higher with components residing outside the defined “safe zone”. The Lewinnek concept of “safe zone” has to be a matter of recent controversy [ 22 , 23 ], nevertheless, it remains an accessible method for confirming technical accuracy after THA [ 24 ]. In the current study, a higher percentage of the patients were within the defined “safe zone” in the DAA group compared to the ALA group (96.9% compared to 85.1% of cases, respectively, for cup anteversion angles and 92.2% compared to 83% of cases, for cup abduction angles).…”

Section: Discussionmentioning

confidence: 99%

Acetabular cup orientation and postoperative leg length discrepancy in patients undergoing elective total hip arthroplasty via a direct anterior and anterolateral approaches

Debi

Slamowicz

Cohen

et al. 2018

BMC Musculoskelet Disord

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BackgroundTotal hip arthroplasty (THA) is considered a successful surgical procedure. It can be performed by several surgical approaches. Although the posterior and anterolateral approaches are the most common, there has been increased interest in the direct anterior approach. The goal of the present study is to compare postoperative leg length discrepancy and acetabular cup orientation among patients who underwent total hip arthroplasty through a direct anterior (DAA) and anterolateral (ALA) approaches.MethodsThe study included 172 patients undergoing an elective THA by a single surgeon at our institution within the study period. Ninety-eight arthroplasties were performed through the ALA and 74 arthroplasties through the DAA. Preoperative planning was performed for all patients. Assessment of the two groups included the following postoperative parameters: abduction angle, cup anteversion angle and leg length discrepancy (LLD). Additional analysis was done to evaluate component positioning by comparing deviation from the Lewinnek zone of safety in both approaches.ResultsFor the DAA the absolute LLD was 11 mm, ranging from -6 mm to 5 mm. For the ALA, the absolute LLD was 36 mm, ranging from -22 mm to 14 mm. None of the DAA patients had an absolute LLD greater than 6 mm. Comparatively, 7.4% of the ALA group exceeded 6 mm of LLD in addition to 2.1% with LLD greater than 10 mm. 15% of the ALA group resided out of the Lewinnek abduction zone compared to 3% of the DAA group (P = 0.016). 17% of the ALA group were out of the Lewinnek anteversion zone as opposed to 8% of the DAA group (P = 0.094).ConclusionOur study demonstrates good component positioning outcomes and LLD values in patients following THA through the DAA compared to the ALA.

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“…This could potentially result in a higher incidence of altered gait mechanics, implant wear, and worse abductor function for this patient population [12,13]. In addition, implant position, specifically cup abduction and anteversion angles, has been a focus of optimization to increase hip stability and decrease implant wear [9,24]. However, Abdel et al [25] have recently called into question the so-called "safe zone" for hip abduction and anteversion.…”

Section: Component Positionmentioning

confidence: 99%

Anatomic Total Hip Component Position Is More Reproducible With the Direct Anterior Approach Using Intraoperative Fluoroscopy

2020

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Background: Total hip arthroplasty (THA) has demonstrated excellent results regardless of the surgical approach. However, the approach used may be a factor in final positioning of implants. We hypothesized that the direct anterior approach (DAA) with fluoroscopy would be associated with more anatomic implant positioning than the posterior approach (PA). Methods: A retrospective review of 200 patients was performed. One hundred patients underwent THA utilizing the PA, and 100 patients, with the DAA. All patients had an anterior-posterior pelvis radiograph preoperatively and postoperatively with a magnification marker present to standardize each radiograph. Exclusion criteria included contralateral THA or any pelvic or femoral deformity. Results: Preoperative radiographs demonstrated identical cohorts with respect to leg length, femoral offset, and total offset. Postoperatively, the DAA achieved more accurate anatomic restoration of leg length (1.6 mm vs 5.5 mm; P < .0001), femoral offset (4.8 mm vs 9.3 mm; P < .0001), and total offset (0.5 mm vs 4.7 mm; P < .0001) compared with the PA. Ideal cup abduction and anteversion were significantly superior to the DAA (96% vs 78%, P ¼ .0002, and 69% vs 24%, P < .0001, respectively). Conclusions: This study is the first to compare anatomic implant positioning between patients undergoing THA with these 2 approaches. All parameters were significantly closer to anatomic implant positioning with the DAA. There are at least 2 potential explanations for this: (1) The DAA implant positioning was performed under fluoroscopic guidance, whereas the PA was not. (2) The PA disrupts the posterior capsule and external rotators, and therefore, increased offset or leg length may be necessary to achieve comparable hip stability with the DAA.

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Acetabular Component Position and the Risk of Dislocation Following Primary and Revision Total Hip Arthroplasty: A Matched Cohort Analysis

Cited by 84 publications

References 23 publications

Relative Contribution of Acetabular and Femoral Reconstruction to Prosthetic Joint Instability Risk after Primary Total Hip Arthroplasty

Relative Contribution of Acetabular and Femoral Reconstruction to Prosthetic Joint Instability Risk after Primary Total Hip Arthroplasty

Acetabular cup orientation and postoperative leg length discrepancy in patients undergoing elective total hip arthroplasty via a direct anterior and anterolateral approaches

Anatomic Total Hip Component Position Is More Reproducible With the Direct Anterior Approach Using Intraoperative Fluoroscopy

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