Cementless Porous-Coated Metaphyseal Sleeves Used for Bone Defects in Revision Total Knee Arthroplasty: Short- to Mid-Term Outcomes

Influence of Stem Dimensions on Radiological and Clinical Results in Revision Knee Arthroplasty with Metaphyseal Sleeves: A Retrospective Analysis

INTRODUCTION

Metaphyseal sleeves (MS) achieve press-fit fixation in Zone 2 during revision total knee arthroplasty (rTKA). The canal filling ratio (CFR) estimates the engagement offered by a stem. The objectives in this study were to evaluate clinical and radiological outcomes in patients undergoing rTKA with stemmed MS and to determine if there is a correlation between these variables and stem length and CFR.

MATERIALS AND METHODS

This retrospective study included 67 patients who underwent rTKA with uncemented stemmed MS, with a minimum follow-up of two years. The radiological outcomes included the stem length and CFR, the incidence of radiolucent lines for each sleeve, measured by the modified Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System for MS (mKSRESS), and limb alignment, measured by Hip-Knee-Ankle (HKA) angle. Functional outcomes comprised the Knee Society Score (KSS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Numerical Rating Score (NRS) for pain.

RESULTS

The mean CFR for femoral and tibial components was 64 ± 12 and 68.4 ± 12.1%, respectively. Radiolucencies were observed in 23.4% of femoral and 44.8% of tibial implants, with no cases of prosthetic loosening. The mean HKA was 178 ± 2.93º, with 94% of the patients within 3º varus-valgus. Patients who were correctly aligned had a significantly higher tibial CFR (69.2 versus 56.5%, respectively, P = 0.049) and stem length (97.7 versus 67.5 mm, respectively, P = 0.029). No correlation was found between CFR or stem length and mKSRESS. Functional outcomes improved significantly in all patients. Tibial CFR showed a weak, but significant correlation (r = 0.270) with KSS function (P = 0.031).

CONCLUSION

Press-fit stems may not be necessary to achieve adequate implant stability when used in combination with an MS, but tibial stem dimensions seem to influence limb alignment and could slightly improve functional outcomes.

Metaphyseal sleeve and straight stem fixation with or without screws for bone defect in complex primary total knee arthroplasty in Eastern Asian populations

BACKGROUND

Massive bone defects present significant challenges in complex primary total knee arthroplasty (TKA). Previous studies with limited sample sizes have demonstrated the potential of metaphyseal sleeves (MS) in addressing such defects. This study mainly aimed to assess the clinical outcomes and survivorship of MS utilized for reconstructing bone defects in complex primary TKA among East Asian patients, with a secondary focus on the use of scews for tibial residual bone defect.

METHODS

A total of 3,672 primary TKAs were performed between January 2016 and December 2020, of which 106 procedures (87 patients) utilized MS in conjunction with straight stems to address bone defects. Among these, 55 (46 patients) incorporated screws for tibial residual bone defect, while 51 (41 patients) were performed without screws. The mean follow-up period was 57.86 months, during which demographic data, operative details, clinical and radiographic outcomes, complications, and implant survivorship were recorded and analyzed.

RESULTS

All cases demonstrated successful osteointegration, with both the endpoint reoperation and revision implant survival rates reaching 100%. The mean Hospital for Special Surgery (HSS) score significantly improved from 56.98 to 82.36 at the final follow-up, resulting in an overall excellent and good outcome rate of 95.40%. Knee conditions were notably worse in the screw group compared to the non-screw group; however, the clinical and radiographic outcomes between the two groups were comparable. Postoperative tibial end-of-stem pain was reported in 9.8% of the non-screw group, while none (0%) in the screw group, reflecting marginal significance (P = 0.0548).

CONCLUSION

The application of metaphyseal sleeves with straight stems represents a promising strategy for addressing massive bone defects in complex primary TKA among East Asian patients. The cement-screw technique, providing potential biomechanical advantages, emerges as a safe and effective solution for managing residual defects surrounding MS placement in tibial site.

Short-term Comparison of Survivorship and Functional Outcomes for Metaphyseal Cones with Short and Long Stems in Revision Total Knee Arthroplasty

Printed porous titanium metaphyseal cones have become a mainstay for managing bone loss in revision total knee arthroplasty (rTKA). A short or long stem is routinely used when implanting a cone to augment fixation and offload stresses. This retrospective analysis compared the short-term survivorships and functional outcomes for use of a short or long stem with a metaphyseal cone.A total of 179 cases using metaphyseal cones and stems with median follow-up of 1.95 years (interquartile range, 1.00-2.14) were compared based on stem type. There were 55 cases with long stem(s) and 124 cases with short stem(s). Cases with both long and short stems were excluded. Demographics, Kaplan-Meier survivorships, and preoperative and 1-year postoperative patient-reported outcome measures (PROMs; 2011 Knee Society Score [KSS] objective knee score, function, and satisfaction scores; EuroQol five-dimension scale; and Short Form Survey Physical Component Summary and Mental Component Summary scores) were compared using t-tests with a significance level of α = 0.05. There were no significant differences in body mass index (mean ± standard deviation) or sex (men [%]) between the short and long stem cohorts (32.3 ± 5.3, 36.3% and 31.5 ± 5.5, 38.2%, respectively; p > 0.05). Patients who had short stems were younger (65.9 ± 8.8 vs. 69.0 ± 9.4, p = 0.0323).Revision-free survivorship for the femoral or tibial component was 100% for long stems and 98.2% for short stems at 1 and 2 years, respectively (log-rank p = 0.6330). The two revisions in the short group were for infection, thus the survivorship for aseptic loosening was 100% at 2 years for both cohorts. There were no significant differences in preoperative or postoperative PROMs.This study demonstrated that highly porous printed metaphyseal cones provided rTKA with excellent early survivorship and similar PROMs whether a short or long stem was used. Additional studies will be needed to discern longer term differences.

Mid-term survivorship and clinical outcomes of revision knee arthroplasty using a mobile bearing tibial tray: A single-center registry review

BACKGROUND

Revision total knee arthroplasty can successfully restore function and relieve pain for patients with failed knee replacements. Mobile-bearing implants were designed to provide greater congruency between the implant and the polyethylene insert. The goal of this study was to review the clinical outcomes and survivorship for a revision mobile-bearing tibial design.

METHODS

A retrospective outcomes review was conducted to assess survivorship and clinical outcomes for a mobile bearing tibial tray, used with metaphyseal sleeves, in revision total knee arthroplasty.

RESULTS

At time of furthest follow-up, KM estimates (95% CI; n with further follow-up) for all-cause revision were 82.5% (75.8%; 87.5%; 42) at 7 years for the clinical assumption (CA), and 88.5% (84.4%,91.6%; 53) at 13 years for the registry assumption (RA). For revision of the tray as the endpoint, survivorship estimates were 93.4% (87.0%,96.7%; 42) at 7 years for CA, and 96.2% (93.2%,97.9%; 53) at 13 years for RA.

CONCLUSION

In this single-center registry evaluation, we found excellent mid-term survivorship and clinical outcomes for a mobile-bearing tibial tray used with metaphyseal sleeves in revision total knee arthroplasty.