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J Knee Surg
DOI: 10.1055/a-2315-7778
Original Article

Short-term comparison of survivorship and functional outcomes for metaphyseal cones with short and long stems in revision total knee arthroplasty

Nicolas S Piuzzi 
1   Orthopedics, Cleveland Clinic, Cleveland, United States (Ringgold ID: RIN2569)
2   Instituto Universitario del Hospital Italiano de Buenos Aires, Buenos Aires, Argentina (Ringgold ID: RIN148357)
,
Emily Hampp
3   Implant and Robotic Research, Stryker, Mahwah, United States
,
Sarah Shi
4   Research and Product Assurance, Stryker, Mahwah, United States
,
Manoshi Bhowmik-Stoker
5   Orthopaedics, Stryker, Mahwah, United States
,
Nickelas Huffman 
6   Orthopedics, Cleveland Clinic, Cleveland, United States (Ringgold ID: RIN2569)
,
Kevin Denehy
7   Orthopaedic surgery, University of Louisville, Louisville, United States
,
David Markel
8   Orthopedic Surgery, Providence-Providence Park Hospital, Novi, United States (Ringgold ID: RIN7432)
,
Daniel D Li
9   Orthopaedics, The Ohio State University, Columbus, United States (Ringgold ID: RIN2647)
,
Michael A Mont
10   Orthopaedic Surgery, Rubin Institute for Advanced Orthopedics, Baltimore, United States (Ringgold ID: RIN479011)
› Author Affiliations Clinical Trial: Registration number (trial ID): NCT02521103, Trial registry: ClinicalTrials.gov (http://www.clinicaltrials.gov/), Type of Study: Prospective, post-market, multi-center evaluation of the clinical outcomes
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Introduction: 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. Methods: A total of 179 cases using metaphyseal cones and stems with median follow-up of 1.95 years (Interquartile range, 1.00 to 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 one-year postoperative patient reported outcome measures (PROMs) [2011 Knee Society Score (KSS) objective knee score, function, and satisfaction scores; EuroQol five-dimension scale (EQ5D); and Short Form Survey (SF12) Physical Component Summary (PCS) and Mental Component Summary (MCS) scores] were compared using t-tests with a significance level of α=0.05. There were no significant differences in body mass index (BMI) (mean ± SD) or sex [men (%)] between the short stem 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). Results: Revision-free survivorship for the femoral or tibial component was 100% for long stems and 98.2% for short stems at one- and two-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 two years for both cohorts. There were no significant differences in preoperative or postoperative PROMs. Conclusion: 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.



Publication History

Received: 20 December 2023

Accepted after revision: 23 April 2024

Accepted Manuscript online:
27 April 2024

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