TY - JOUR
T1 - Alignment in Medial Fixed-Bearing Unicompartmental Knee Arthroplasty
T2 - The Limb Has a Leg Up on the Component
AU - Slaven, Sean E.
AU - Cody, John P.
AU - Sershon, Robert A.
AU - Ho, Henry
AU - Hopper, Robert H.
AU - Fricka, Kevin B.
N1 - Funding Information:
Source of Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The Inova Health System provides financial support for the Anderson Orthopaedic Research Institute (AORI) but does not restrict or define the scope of the research undertaken by AORI.
Publisher Copyright:
© 2021 Elsevier Inc.
PY - 2021/12
Y1 - 2021/12
N2 - Background: To assess how implant alignment affects unicompartmental knee arthroplasty (UKA) outcome, we compared tibial component alignment of well-functioning UKAs against 2 groups of failed UKAs, revised for progression of lateral compartment arthritis (“Progression”) and aseptic loosening (“Loosening”). Methods: We identified 37 revisions for Progression and 61 revisions for Loosening from our prospective institutional database of 3351 medial fixed-bearing UKAs performed since 2000. Revision cohorts were matched on age, gender, body mass index, and postoperative range of motion with “Successful” unrevised UKAs with minimum 10-year follow-up and Knee Society Score ≥70. Tibial component coronal (TCA) and sagittal (TSA) plane alignment was measured on postoperative radiographs. Limb alignment was quantified by hip-knee-ankle (HKA) angle on long-leg radiographs. In addition to directly comparing groups, a multivariate logistic regression examined how limb and component alignments were associated with UKA revision. Results: In the Progression group, component alignment was similar to the matched successes (TCA 3.6° ± 3.5° varus vs 5.1° ± 3.5° varus, P = .07; TSA 8.4° ± 4.4° vs 8.8° ± 3.6°, P = .67), whereas HKA angle was significantly more valgus (0.3° ± 3.6° valgus vs 4.4° ± 2.6° varus, P < .001). Loosening group component alignment was also similar to the matched successes (TCA 6.1° ± 3.7° varus vs 5.9° ± 3.1° varus, P = .72; TSA 8.4° ± 4.6° vs 8.1° ± 3.9°, P = .68), and HKA was significantly more varus (6.1° ± 3.1° varus vs 4.0° ± 2.7° varus, P < .001). Using a multivariate logistic regression, HKA angle was the most significant factor associated with revision (P < .001). Conclusion: In this population of revised UKAs and long-term successes, limb alignment was a more important determinant of outcome than tibial component alignment. Level of Evidence: Level III case-control study.
AB - Background: To assess how implant alignment affects unicompartmental knee arthroplasty (UKA) outcome, we compared tibial component alignment of well-functioning UKAs against 2 groups of failed UKAs, revised for progression of lateral compartment arthritis (“Progression”) and aseptic loosening (“Loosening”). Methods: We identified 37 revisions for Progression and 61 revisions for Loosening from our prospective institutional database of 3351 medial fixed-bearing UKAs performed since 2000. Revision cohorts were matched on age, gender, body mass index, and postoperative range of motion with “Successful” unrevised UKAs with minimum 10-year follow-up and Knee Society Score ≥70. Tibial component coronal (TCA) and sagittal (TSA) plane alignment was measured on postoperative radiographs. Limb alignment was quantified by hip-knee-ankle (HKA) angle on long-leg radiographs. In addition to directly comparing groups, a multivariate logistic regression examined how limb and component alignments were associated with UKA revision. Results: In the Progression group, component alignment was similar to the matched successes (TCA 3.6° ± 3.5° varus vs 5.1° ± 3.5° varus, P = .07; TSA 8.4° ± 4.4° vs 8.8° ± 3.6°, P = .67), whereas HKA angle was significantly more valgus (0.3° ± 3.6° valgus vs 4.4° ± 2.6° varus, P < .001). Loosening group component alignment was also similar to the matched successes (TCA 6.1° ± 3.7° varus vs 5.9° ± 3.1° varus, P = .72; TSA 8.4° ± 4.6° vs 8.1° ± 3.9°, P = .68), and HKA was significantly more varus (6.1° ± 3.1° varus vs 4.0° ± 2.7° varus, P < .001). Using a multivariate logistic regression, HKA angle was the most significant factor associated with revision (P < .001). Conclusion: In this population of revised UKAs and long-term successes, limb alignment was a more important determinant of outcome than tibial component alignment. Level of Evidence: Level III case-control study.
KW - component alignment
KW - hip-knee-ankle angle
KW - mechanical alignment
KW - medial compartment aseptic loosening and subsidence
KW - revision for progression of lateral compartment osteoarthritis
KW - unicondylar knee arthroplasty
UR - http://www.scopus.com/inward/record.url?scp=85114235548&partnerID=8YFLogxK
U2 - 10.1016/j.arth.2021.08.015
DO - 10.1016/j.arth.2021.08.015
M3 - Article
C2 - 34489145
AN - SCOPUS:85114235548
SN - 0883-5403
VL - 36
SP - 3883
EP - 3887
JO - Journal of Arthroplasty
JF - Journal of Arthroplasty
IS - 12
ER -