BMC Musculoskeletal Disorders · Published 2026-05-01 · Journal article · DOI 10.1186/s12891-026-09912-9 · PMID: 42067872 · PMC · Cited by 3 (Crossref)
Jianfu Zhu, Qijin Wang, Xiaodan Lin, Xu Wang, Yuhua Feng, Xiaohong Fan, Xiaolu Wang, Qiujin Xia, Jiliang Chen, Hongkuan Lin, Chengshou Lin, Qingshan Xu, Zhenbao Lu
Abstract Background Distal femoral resection is a determinant of coronal alignment and extension-gap symmetry in total knee arthroplasty (TKA). Conventional intramedullary (IM) alignment relies on a fixed femoral canal-referenced valgus angle, which can be affected by anatomical variability and does not account for extension-gap ligament tension. By contrast, a ligament-tension-guided extramedullary (EM) workflow preserves the femoral canal and uses full-extension tension feedback rather than a preset angle to guide coronal positioning. Methods This single-centre retrospective cohort study analysed 76 unilateral primary TKAs performed by a single senior surgeon between September 2019 and January 2024 (EM, n = 37; IM, n = 39). In the EM group, coronal guide positioning was based on full-extension tension feedback without a preset valgus angle, whereas the IM group used conventional intramedullary alignment with a fixed 6° femoral canal-referenced valgus setting. The primary outcome was coronal precision, defined as the absolute deviation of the mechanical lateral distal femoral angle (mLDFA) from 90° on standardised full-length weight-bearing radiographs 6 weeks postoperatively. Prespecified secondary outcomes were mLDFA within ± 3° of 90°, intraoperative visible blood loss, distal femoral resection-step time, and haemoglobin (Hb) decrease within 24 h. Results Compared with conventional IM alignment, the EM workflow was associated with greater coronal precision, with a smaller absolute deviation of the mLDFA from the 90° target (P = 0.016) and a higher proportion of knees within ± 3° of target (P = 0.020). Intraoperative visible blood loss and haemoglobin decrease within 24 h were lower in the EM group (both P < 0.001), whilst distal femoral resection-step time was comparable (P = 0.235). Exploratory early recovery measures were favourable in the EM group and should be interpreted cautiously. At 12 months, KSS and WOMAC scores, complication rates, and revision-free status were comparable, and no revision was required in either group. Conclusions In primary TKA, ligament-tension-guided EM distal femoral resection was associated with greater coronal precision and a lower perioperative bleeding burden than fixed-angle IM alignment, without clear between-group differences in 12-month clinical outcomes. These findings support prospective evaluation of tension-informed coronal target selection.
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Zhu, J., Wang, Q., Lin, X., et al. (2026). Ligament-tension-guided versus fixed-angle distal femoral coronal target selection in primary total knee arthroplasty using a manual alignment workflow: a retrospective cohort study. BMC Musculoskeletal Disorders. https://doi.org/10.1186/s12891-026-09912-9