Impact of joint line orientation on clinical outcomes in bilateral Oxford mobile-bearing unicompartmental knee arthroplasty

Nishida, Ryota; Hiranaka, Takafumi; Kamenaga, Tomoyuki; Hida, Yasuhiro; Fujishiro, Takaaki; Okamoto, Koji; Kuroda, Ryosuke; Matsumoto, Tomoyuki

doi:10.1016/j.knee.2020.11.018

Cited by 11 publications

(7 citation statements)

References 34 publications

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“…Had it been possible to measure bearing rotation and include this in the calculation, there might have been a significant relationship between overhang and wear. The bearing is typically closest to wall in mid flexion and moves ~1 mm medially in extension and full flexion [41]. Therefore, distance between the wall and bearing in this study is likely an indicator of the maximum distance.…”

Section: Discussionmentioning

confidence: 98%

Polyethylene bearing wear is comparable for cemented and cementless Oxford unicompartmental knee replacements: Ten‐year results of a randomized controlled trial

Arthur,

Ghosh,

Mohammad

et al. 2024

Knee surg. sports traumatol. arthrosc.

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PurposeThere is concern that using cementless components may increase polyethylene wear of the Oxford unicompartmental knee replacement (OUKR). Therefore, this study aimed to measure bearing wear at 10 years in patients from a randomized trial comparing Phase 3 cemented and cementless OUKRs and to investigate factors that may affect wear. It was hypothesized that there would be no difference in wear rate between cemented and cementless OUKRs.MethodsBearing thickness was determined using radiostereometric analysis at postoperative, 3‐month, 6‐month, 1‐year, 2‐year, 5‐year and 10‐year timepoints. As creep occurs early, wear rate was calculated using linear regression between 6 months and 10 years for 39 knees (20 cemented, 19 cementless). Associations between wear and implant, surgical and patient factors were analysed.ResultsThe linear wear rate of the Phase 3 OUKR was 0.06 mm/year with no significant difference (p = 0.18) between cemented (0.054 mm/year) and cementless (0.063 mm/year) implants. Age, Oxford Knee Score, component size and bearing thickness had no correlation with wear. A body mass index ≥ 30 was associated with a significantly lower wear rate (p = 0.007) as was having ≥80% femoral component contact area on the bearing (p = 0.003). Bearings positioned ≥1.5 mm from the tibial wall had a significantly higher wear rate (p = 0.002).ConclusionsAt 10 years, the Phase 3 OUKR linear wear rate is low and not associated with the fixation method. To minimize the risk of wear‐related bearing fracture in the very long‐term surgeons should consider using 4 mm bearings in very young active patients and ensure that components are appropriately positioned, which is facilitated by the current instrumentation.Level of EvidenceLevel III, Retrospective Comparative Study.

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Section: Discussionmentioning

confidence: 98%

Polyethylene bearing wear is comparable for cemented and cementless Oxford unicompartmental knee replacements: Ten‐year results of a randomized controlled trial

Arthur,

Ghosh,

Mohammad

et al. 2024

Knee surg. sports traumatol. arthrosc.

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“…There has been no previous study on joint line alteration after Oxford UKA. Only one report by Nishida et al showed that the medially inclined joint line orientation (angle between the joint line and the floor) was associated with a declined postoperative clinical outcome [ 25 ], indicating that the joint line alteration can affect the clinical outcome. Further investigation is required to clarify the relationship between changes in LDFA and MPTA and the clinical outcome.…”

Section: Discussionmentioning

confidence: 99%

Preoperative Arithmetic Hip-Knee-Ankle Angle as a Predictor of Postoperative Leg Alignment in Medial Oxford Unicompartmental Knee Arthroplasty

Hiranaka,

Fukai,

Tanaka

et al. 2024

Cureus

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Introduction This study aimed to evaluate whether the arithmetic hip-knee-ankle angle (aHKA) can be used to predict the postoperative HKA. Methods This study included 248 knees in 166 patients who underwent Oxford unicompartmental knee arthroplasty (UKA) between February 2021 and November 2022. Through preoperative and postoperative long-leg radiography, the medial proximal tibial angle (MPTA) and the lateral distal femoral angle (LDFA) were expressed as the deviation from the perpendicular line to the mechanical axes, and the mechanical HKA (mHKA) was defined as the angle between the femoral and tibial mechanical axes. Using the MPTA and LDFA, the arithmetic HKA (aHKA; MPTA + LDFA) and the joint line obliquity (JLO; MPTA − LDFA) were calculated, and the preoperative and postoperative values were compared. Results The preoperative aHKA and the postoperative mHKA values were similar (−0.38° ± 2.96°) and significantly smaller than the difference between the preoperative and postoperative mHKAs (4.58° ± 3.60°, P < 0.05). Meanwhile, the MPTA tended to be varus, and the LDFA tended to be valgus. Eventually, the JLO inclined more medially from −6.33° ± 3.42° preoperatively to −8.97° ± 3.92° postoperatively, representing a significant difference ( P < 0.05). Conclusion The preoperative aHKA was similar to the postoperative mHKA. Therefore, it can be regarded as a predictor of postoperative leg alignment after Oxford UKA. Meanwhile, there was a medial incline of the joint line. Further investigation is required to evaluate the effect of such a joint line alteration.

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“…However, in our mild varus group, there was very little change in alignment postoperatively. Given the minimal effect of osteophytes and intra-articular deformities, the concept of resurfacing surgery in Oxford UKA could have been directly implemented [13].…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have reported good clinical results using kinematically aligned TKA as a method of preserving constitutional limb alignment [11,12]. Moreover, using UKA, the patient's native limb alignment can be restored [13]. Therefore, it is possible that the varus alignment after UKA does not affect PROMs.…”

Section: Introductionmentioning

confidence: 99%

Perioperative varus alignment does not affect short-term patient-reported outcome measures following mobile-bearing unicompartmental knee arthroplasty

et al. 2022

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Background Although favorable long-term survival of Oxford unicompartmental knee arthroplasty (UKA) has been reported regardless of postoperative varus alignment, the effect of degree of varus alignment on patient-reported outcome measures (PROMs) remains unclear. Furthermore, the Forgotten Joint Score-12 (FJS-12), which has a low ceiling effect, may be useful for such assessment. The objective of this study was to evaluate short-term clinical outcomes after Oxford UKA in knees with a greater degree of preoperative varus alignment focusing on use of the FJS-12. Methods This retrospective study involved 66 knees that had undergone primary Oxford UKA. Based on the hip-knee-ankle angle, the knees were divided into two alignment groups: severe varus group (≥ 185° varus alignment) and a mild varus group (< 185° varus alignment). PROMs, including the FJS-12, Knee Injury and Osteoarthritis Outcome Score, and Knee Society Score, were obtained pre- and postoperatively for assessment of clinical outcomes. In addition, the ceiling effect of the FJS-12 was evaluated. Results All PROMs showed significant improvement after surgery. However, there were no statistically significant differences between the severe varus group and the mild varus group. Moreover, no ceiling effect was found for the FJS-12 in this study. Conclusion Short-term results were good for Oxford UKA in knees with a greater degree of varus alignment and were not significantly different from those in knees with mild varus alignment.

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Impact of joint line orientation on clinical outcomes in bilateral Oxford mobile-bearing unicompartmental knee arthroplasty

Cited by 11 publications

References 34 publications

Polyethylene bearing wear is comparable for cemented and cementless Oxford unicompartmental knee replacements: Ten‐year results of a randomized controlled trial

Polyethylene bearing wear is comparable for cemented and cementless Oxford unicompartmental knee replacements: Ten‐year results of a randomized controlled trial

Preoperative Arithmetic Hip-Knee-Ankle Angle as a Predictor of Postoperative Leg Alignment in Medial Oxford Unicompartmental Knee Arthroplasty

Perioperative varus alignment does not affect short-term patient-reported outcome measures following mobile-bearing unicompartmental knee arthroplasty

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