"True Incidence of Hip Dislocation After Primary THA - a Nationwide Population Study"

The primary objective is to report the true incidence of hip dislocations in primary THA patients within 2 years of index surgery.

Secondary, patient and component characteristics (age, sex, comorbidity, cemented/uncemented, approach, head diameter) are analyzed as potential risk factors for dislocation. Specific components may be analyzed based on number.

Study Overview

• Status: Unknown
• Conditions: Hip Dislocation
• Intervention / Treatment: Other: THA

Detailed Description

Based on published literature and personal experience, most hip surgeons have an assumption of the degree of hip dislocation. This will be the first study to reveal the actual extent of this specific complication in a large population. It will give surgeons knowledge of the current standards -both on a national and hospital level. Depending on the results and comparisons to relevant countries, the investigators will be able to either substantiate or forced to rethink current procedures. This applies to both surgical access and use of specific components.

Since the vast majority of dislocations appear within 1-2 years after primary surgery (29), the follow-up period will be 2 years. By applying the National Patient Registry the investigators are able to identify any type of patient contact with the hospital system throughout Denmark in these 2 years. Patients assigned with correct diagnostic and procedural codes for dislocation and reduction are identified. However, the investigators will also find the cases of dislocation that are incorrectly coded in the registry. Therefore, the investigators will manually look in all the patient files from orthopedic contacts regardless of assigned diagnostic and procedural codes. Additionally, emergency room and internal medicine contacts are scanned with a broad and comprehensive range of relevant hip- and dislocation-related codes to identify episodes of hip dislocation, which are incorrectly coded. These patient files will also be manually reviewed.

If a patient is revised within the first 2 years, the follow-up period ends on the revision date. Revisions are also registered in the Danish Hip Arthroplasty Registry. However, the completeness is 93-95% and therefore lower than for primary operations. In order to have the complete set of revisions, the investigators will enrich our data with an extraction from the National Patient Registry by applying all approved hip revision codes

• Study Type: Observational
• Enrollment (Actual): 32500

Contacts and Locations

Study Locations

• Denmark
  • Region Of Southern Denmark
    • Esbjerg, Region Of Southern Denmark, Denmark, 6700
      • Hospital of South West Jutland

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Retrospective, we include patients with the diagnosis "primary/idiopathic hip OA". Patients are identified by data extraction from the Danish Hip Arthroplasty Registry. From 2010-2014 an average of 9000 hips/year received a primary THA and about 80% of these patients were diagnosed with idiopathic/primary arthritis. Therefore, we tend to include approximately 36.000 hips. We also include the second hip, if a patient undergoes 2 primary operations in our inclusion period and this is adjusted for in the analysis.

Description

Inclusion Criteria:

• patients with the diagnosis "primary/idiopathic hip OA and inserted THA from 01.01.2010 - 31.12.2014.

Exclusion Criteria:

• patients receiving a resurfacing hip arthroplasty and hip revisions
• patients with incomplete registry data
• patients with previous hip surgery

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Retrospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hip dislocation	The true incidence of hip dislocation calculated as proportion presented with 95% confidence intervals (CI).	2 years.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Age	Potential risk factor found by logistic regression analysis	2 years.
Sex	Potential risk factor found by logistic regression analysis	2 years.
Comorbidity	Potential risk factor found by logistic regression analysis	2 years.
Fixation of components	Potential risk factor found by logistic regression analysis	2 years.
Surgical approach	Potential risk factor found by logistic regression analysis	2 years.
Head diameter of prosthesis	Potential risk factor found by logistic regression analysis	2 years.
Time to dislocation	Time to first dislocation presented by Kaplan-Meier plot.	2 years.
Development in complication (dislocation) over time.	Incidence each year (2010-2014) calculated as proportion presented with 95% confidence intervals (CI) and compared statistically depending on distribution.	5 years.

Collaborators and Investigators

• Sponsor: University of Southern Denmark

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2018
• Primary Completion (Anticipated): June 1, 2019
• Study Completion (Anticipated): October 1, 2019

Study Registration Dates

• First Submitted: February 21, 2019
• First Submitted That Met QC Criteria: February 27, 2019
• First Posted (Actual): March 1, 2019

Study Record Updates

• Last Update Posted (Actual): March 1, 2019
• Last Update Submitted That Met QC Criteria: February 27, 2019
• Last Verified: February 1, 2019

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Wounds and Injuries; Joint Diseases; Musculoskeletal Diseases; Hip Injuries; Hip Dislocation; Joint Dislocations
• Other Study ID Numbers: 3-3013-2128/1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No
• IPD Plan Description: Data will not be shared.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No