Comparing Articulating Spacers for Periprosthetic Joint Infection After Primary Total Hip Arthroplasty: All-Cement Versus Real-Component Articulating Spacers

Does the Degree of Liner Constraint Increase Risk of Complications in Articulating Spacers in Two-stage Revision After THA?

BACKGROUND

Two-stage revisions for chronic periprosthetic joint infections (PJIs) often include antibiotic-loaded cement spacers to control for infection and preserve function. While studies have reported on complications (dislocations, readmissions, and reoperations) after static versus articulating spacer types, there is a paucity of evidence about whether the degree of spacer constraint in articulating spacers affects these complications. This study aims to address a key gap in understanding as to whether the level of spacer constraint affects complications in two-stage revision THA utilizing articulating spacers.

QUESTIONS/PURPOSES

(1) Among patients receiving nonconstrained versus constrained articulating antibiotic spacers during first-stage revision THA for PJI, are there differences in major complications, such as dislocation, loosening, periprosthetic fracture, reinfection, and unplanned revisions? (2) After second-stage reimplantation, do patients who received a nonconstrained versus constrained liner during the first stage show differences in the risk of complications, reoperations, and readmissions?

METHODS

This is a retrospective review of 539 patients who underwent two-stage revision THA for PJI at a single-specialty, urban academic referral center between July 2011 and March 2023. Of these 539 patients, 72% (388) were excluded for undergoing a full component revision (femoral or acetabular) for any reason before their first stage, 3% (15) for receiving static spacers, and 6% (35) for receiving prefabricated femoral mono-block stems as part of their first stage. Those who underwent only liner exchange were not excluded. The remaining 19% (101 of 539) of patients were included in the final analysis and categorized by degree of liner constraint: 32 were in the nonconstrained group and 69 were in the constrained group. All surgeons included in this study specialize in adult reconstruction and are fellowship trained, and the selected level of constraint was solely based on their routine practice for articulating spacer construct. Baseline characteristics and clinical data, including age, self-reported gender, race, BMI, American Society of Anesthesiologists score, smoking status, surgical history, and perioperative details, were collected. There were no differences in baseline characteristics between the groups except for smoking status. A priori power analysis determined that 150 patients (75 per group) would be needed to detect a statistical difference in the risk of dislocation between groups, assuming a 20% dislocation risk for the constrained group, at a 0.05 alpha level, and 80% power.

RESULTS

Between patients receiving nonconstrained versus constrained liners, there were no differences in complications after the first stage of revision. Three percent (1 of 32) of the nonconstrained liners developed dislocations compared with 3% (2 of 69) in the constrained group (relative risk [RR] 1.1 [95% confidence interval (CI) 0.09 to 12.3]; p > 0.99). Three percent (1 of 32) of the nonconstrained group developed periprosthetic fractures compared with 7% (5 of 69) in the constrained group (RR 0.4 [95% CI 0.05 to 3.69]; p = 0.72). Similarly, 3% (1 of 32) versus 7% (5 of 69) had persistent infection (RR 0.4 [95% CI 0.05 to 3.69]; p = 0.72). One incident of loosening occurred in the constrained group. There were also no differences in spacer revision incidence: 10% (3 of 32) of the nonconstrained group and 10% (7 of 69) of the constrained group underwent an unplanned revision after the first stage (RR 1.0 [95% CI 0.29 to 3.91]; p = 0.91). For the second stage, dislocation was 14% (3 of 21) in the nonconstrained group and 10% (5 of 52) in the constrained group (RR 1.1 [95% CI 0.2 to 5.9]; p > 0.99). When comparing periprosthetic fractures, 10% (2 of 21) of the nonconstrained group developed periprosthetic fractures compared with 4% (2 of 52) in the constrained group (RR 2.2 [95% CI 0.3 to 16.6]; p = 0.78). Nineteen percent (4 of 21) in the nonconstrained group had persistent infection compared with 12% (6 of 52) in the constrained group (RR 1.5 [95% CI 0.39 to 5.74]; p = 0.81). The occurrence of readmission after the second stage was 19% (4 of 21) in the nonconstrained group compared with 15% (8 of 52) in the constrained group (RR 1.1 [95% CI 0.3 to 3.9]; p > 0.99). Twenty-four percent (5 of 21) of patients in the nonconstrained group required a surgery-related emergency department visit compared with 13% (7 of 52) in the constrained group (RR 1.6 [95% CI 0.4 to 5.6]; p = 0.64). The incidence of reoperation was 14% (3 of 21) in the nonconstrained group and 13% (7 of 52) in the constrained group (RR 0.9 [95% CI 0.2 to 3.8]; p > 0.99).

CONCLUSION

Our results indicated no differences in the risk of dislocations, reinfections, reoperations, and readmissions between patients undergoing constrained versus nonconstrained articulating spacers for two-stage revision THA. Because constrained liners are typically preferred in patients at higher risk of instability, our findings suggest that their use does not necessarily increase the risk of complications. However, because of the small sample size, larger studies are needed to demonstrate whether there is superiority of liner constraint in this patient population.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Spacers in two-stage strategy for periprosthetic infection

In two-stage revision of infected implants, the first stage involves removing the implant and implanting a joint spacer, and the second stage involves implanting a new prosthesis at least 6 weeks later. Spacers have two main functions: local administration of high-dose antibiotics, and preservation of the joint space by reducing soft tissue retraction and improving patient comfort until reimplantation. The present review aims to detail the necessary characteristics of antibiotics added to cement to achieve good joint diffusion, to describe the steps of two-stage revision, and to present the types of spacer available according to the joint and complications. The antibiotic used in the spacer must be heat-resistant, water-soluble and chemically stable in the cement. Gentamicin and vancomycin are generally preferred. We recommend at least 3 months' systematic antibiotic therapy for periprosthetic joint infection. Reimplantation is performed either at 6 weeks without antibiotic washout or 3 months after 2 weeks' washout Spacers may be static (non-articulating) or dynamic (articulating). Static spacers are mainly used in the knee or hip in cases of severe bone defect or risk of soft-tissue lesions. An articulating spacer enables some joint functions to be preserved in the knee, hip or shoulder. The most frequent complications are the dislocation of dynamic spacers and the breakage of static or dynamic spacers. To optimize efficacy and minimize complications, the biomechanical and bacteriological characteristics of spacers must be considered. LEVEL OF EVIDENCE: Expert opinion.

Prosthetic articulating spacers as a preferred option for two-stage revision arthroplasty in chronic periprosthetic joint infection

PURPOSE

The study aimed to compare the infection control rates, mechanical complications, and functional outcomes between prosthetic and cement spacers in two-stage revision arthroplasty for chronic periprosthetic joint infection (PJI).

PATIENTS AND METHODS

Data from patients treated for chronic PJI in our center from 2014 to 2023 were retrospectively collected and the patients were divided into the prosthetic spacer (PS) and cement spacer (CS) groups based on the type of spacer used for the first-stage surgeries. Data on patients' demographics and clinical scores were harvested. Infection control rates and mechanical complications were compared between the two groups by using chi-square tests and log-rank analysis.

RESULTS

The study involved 113 cases, with a mean age of 64 ± 11.45 years (range, 31-88 years), with 48 cases in the PS group, 65 in the CS group, and all patients were followed up for at least 1 year (average 52.68 ± 26.07 months). Five patients in the PS group (10.42%) and six in the CS group (9.23%) developed recurrent infections, with no significant difference found in infection control rates (P = 0.833). The joint function score after the first-stage surgeries was higher in the PS group than in the CS group (P = 0.021). The incidence of mechanical complications, including dislocation, spacer fracture, and periprosthetic fracture, was significantly lower in the PS group than in the CS group (P = 0.024). The proportion of patients who underwent second-stage surgeries was lower in the PS group than in the CS group (58.3% vs 70.77%, P = 0.169).

CONCLUSION

For most patients with chronic PJI, PS can be used as the preferred option for two-stage revision arthroplasty.

Articulating spacers: what are available and how to utilize them?

Periprosthetic joint infection (PJI) is the most devastating complication following total joint arthroplasty (TJA) and is posing a global healthcare challenge as the demand for TJA mounts. Two-stage exchange arthroplasty with the placement of antibiotic-loaded spacers has been shown to be efficacious against chronic PJI. This study aimed to review the key concepts, types, and outcome evaluations of articulating spacers in the two-stage exchange for PJI. Previous studies indicated that articulating spacers have been widely used due to better functional improvement and a comparable infection control rate relative to static spacers. Several types of articulating spacers are reportedly available, including hand-made spacers, spacers fashioned from molds, commercially preformed spacers, spacers with additional metal or polyethylene elements, new or autoclaved prosthesis, custom-made articulating spacers, and 3D printing-assisted spacers. However, limited evidence suggested no significant difference in clinical outcomes among the different subtypes of articulating spacers. Surgeons should be familiar with different treatment strategies when using various spacers to know which is the most appropriate.