Risk of Revision Following Knee Arthroplasty in Bariatric Surgery Patients

Risk of Revision and Other Complications Following Knee Arthroplasty in Patients Previously Exposed to Bariatric Surgeries: A Nationwide, Register-based Study

Previous studies have investigated the outcomes of Knee Arthroplasty (KA) following Bariatric Surgery (BAS), but with substantial limitations as not stratifying for Body Mass Index (BMI) at time of KA or not addressing the type of BAS (gastric bypass, banding or sleeve). Since BMI varies greatly in patients with previous BAS, it is likely that BMI affects outcomes after KA in BAS-operated patients.

The investigators believe that stratifying for BMI would explain the contradictions with the previous research in this patient group when it comes to the risk of revision after KA.

Study Overview

• Status: Completed
• Conditions: Bariatric Surgery Candidate; Prosthesis-Related Infections; Prosthesis Failure; Prosthesis Survival; Arthritis Knee
• Intervention / Treatment: Other: BAS; Other: Non-BAS

• Study Type: Observational
• Enrollment (Actual): 99965

Contacts and Locations

Study Locations

• Denmark
  • Copenhagen, Denmark
    • Orthopaedic department, Bispebjerg Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

The investigators will include patients with primary/idiopathic or secondary (due to meniscus or cruciate ligament lesion) osteoarthritis (OA) who received primary KA in the period from 2011 and 2 years earlier to data-extraction date. Patients will be identified from the DKR. Patients are followed for 2 years, until first revision, death or migration, whichever comes first.

Description

Inclusion Criteria:

• Primary knee arthroplasty due to osteoarthritis

Exclusion Criteria:

• Primary knee arthroplasty due to traumatic osteoarthritis.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
BAS group; Patients who received bariatric surgery prior to their knee arthroplasty	Other: BAS; NOMESCO (Nordic Medico-Statistical Committee) Classification of Surgical Procedures (KJDF10 & KJDF11 [gastric bypass]; KJDF20 & KJDF21 [gastric banding]; KJDF40, KJDF41, KJDF96 & KJDF97 [gastric sleeve]).
Non-BAS group; Patients who did not receive bariatric surgery prior to their knee arthroplasty	Other: Non-BAS; Patients without BAS codes

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hazard rate of Revision due to any cause	Revision surgery is defined as surgery with debridement and/or exchange of at least one component	within 90 days and within 2 years
Hazard rate of Revision due to infection	Our definition of infection is adapted from the European Bone and Joint Infection Society (EBJIS) criteria as at least one of the following A. An indication of deep infection is reported to the Danish knee arthroplasty register (DKR) by the surgeon on revision surgery B. At least 2 deep-tissue samples of phenotypically indistinguishable bacteria isolated from at least 3 deep-tissue samples C. One or more positive intraoperative samples from a closed fluid aspirate AND a biopsy (fluid AND tissue) of phenotypically indistinguishable bacteria isolated.	within 90 days and within 2 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hazard rate of Knee related antibiotic use within 30- and 90-days following KA	the use of one of the following oral antibiotics: dicloxacillin, flucloxacillin, phenoxymethylpenicillin, amoxicillin, oral ciprofloxacin, roxithromycin, linezolid, cefuroxime and cefalexin	within 30- and 90-days following KA
Hazard rate of Antibiotic use due to other causes	the use of one of oral antibiotics other than those that were mentioned in outcome 3.	within 30- and 90-days following KA
Mortality	Mortality registered in the Danish Civil Registration System (DCRS) by date	2 years postoperatively

Collaborators and Investigators

• Sponsor: Bispebjerg Hospital
• Investigators: Study Director: Søren Overgaard, MD,DMSc,Prof, Department of orthopedic surgery, Bispebjerg University Hospital, Denmark

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2024
• Primary Completion (Actual): December 2, 2024
• Study Completion (Actual): February 1, 2025

Study Registration Dates

• First Submitted: September 7, 2023
• First Submitted That Met QC Criteria: May 27, 2024
• First Posted (Actual): May 30, 2024

Study Record Updates

• Last Update Posted (Actual): February 27, 2026
• Last Update Submitted That Met QC Criteria: February 24, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: arthroplasty; revision; bariatric
• Additional Relevant MeSH Terms: Postoperative Complications; Pathologic Processes; Infections; Pathological Conditions, Signs and Symptoms; Prosthesis Failure; Prosthesis-Related Infections
• Other Study ID Numbers: p-2023-14433

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No