JOA - 2026-05-22 - Journal Article
Metal Block Augmented Tibial Prosthesis Construct in Primary and Aseptic Revision Cemented Total Knee Arthroplasty: Patient-Reported Outcome Measures and Implant Survival.
Clement ND, Moran R, Martinson E, Simpson PMS, Macpherson GJ, Scott CEH
Topics
Key Takeaway
Tibial metal block augments in primary and aseptic revision TKA achieved 98.8% reoperation-free survival at mean 8-year follow-up with PROM improvements equivalent to standard primary TKA.
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Summary
This single-center retrospective study compared OKS, EQ-5D-3L, and EQ-VAS outcomes and implant survivorship in patients receiving 5 or 10 mm medial tibial block augments in primary or aseptic revision TKA against a standard primary TKA control cohort. At mean 8-year follow-up, reoperation-free survival was 98.8% (95% CI 96.5–100%) with only one periprosthetic fracture and no revisions. PROM improvements were statistically and clinically equivalent across groups after confounder adjustment, though revision TKA performed for failed medial UKA showed a clinically meaningful but non-significant OKS deficit of -3.1 points versus standard primary TKA.
Key Limitation
The control group is incompletely characterized in size and baseline demographics, making confounder adjustment reliability uncertain and potentially confounding the equivalence conclusion.
Original Abstract
BACKGROUND
Bone loss presents a technical challenge in total knee arthroplasty (TKA). Despite increasing utilization, there is limited evidence concerning the functional outcomes and implant survivorship associated with the use of medial tibial block augments.
METHODS
A retrospective single-center study was conducted to compare patient-reported outcome measures (PROMs) and survivorship of TKA using augments in both primary (pTKA) and revision (revTKA) procedures against a cohort of pTKA without augments. A total of 89 patients underwent aseptic revTKA, and 34 underwent pTKA using an augment. Patients who underwent TKA using five or 10 mm augments between 2011 and 2020 were identified from an institutional implant registry and linked to a prospectively collected PROMs database. The PROMs included the Oxford Knee Score (OKS), EQ-5D-3L, and EQ VAS, assessed preoperatively and at 12 months postoperatively.
RESULTS
At a mean follow-up of eight years, there were no revisions and one periprosthetic fracture, which resulted in a reoperation survival of 98.8% (95% confidence interval (CI) 96.5 to 100%). Improvements in PROMs were not significantly (P ≥ 0.212) or clinically meaningfully different between revTKA or pTKA with augments and pTKA without augments after adjustment for confounders. However, pTKA with an augment had significantly worse preoperative OKS (mean difference 4.6, P = 0.001), but was not different postoperatively (P = 0.078) because of greater improvement. Where revTKA was performed for medial unicompartmental knee arthroplasty, clinically meaningful worse improvements in the OKS (-3.1, P = 0.064), EQ-5D (-0.078, P = 0.112), and EQ-VAS (-5.0, P = 0.162) compared to pTKA without an augment were found, but without statistical significance.
CONCLUSION
Tibial augment use in primary and aseptic revision TKA was associated with excellent implant survival and comparable PROMs to standard pTKA. These findings support the use of augments as a reliable reconstructive strategy for medial tibial bone loss.