There is no standardised measurement approach for medial proximal tibial angle after unicompartmental knee arthroplasty: A systematic review.
Sina Hajiaghajani, Ali Soltani Farsani, Sina Aminizadeh et al.
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In 30 seconds
This systematic review examined radiographic methods for measuring the medial proximal tibial angle (MPTA) after unicompartmental knee arthroplasty (UKA), where a prosthetic tibial compartment complicates assessment. It included 23 studies involving 4,075 patients and one cadaveric study with 26 specimens. Reporting was heterogeneous: 12 studies did not describe their measurement technique, and reliability reporting was limited. Three broad approaches were identified, but the review found no standardised, validated method, limiting comparability across studies.
Key findings
- Of 23 studies, 12 did not specify how MPTA was measured after UKA.
- Three approaches were identified: tibial component coronal angle as a proxy, medial-to-lateral joint-line landmarks, and the Cartier-type angle.
- Only six studies reported both inter- and intra-observer reliability with specific statistical measures; eleven reported no reliability data.
Why it matters
MPTA is used to describe tibial alignment, but inconsistent landmarks and incomplete reliability reporting make results difficult to compare across UKA studies. This limits interpretation of the evidence on postoperative alignment and highlights the need for measurement methods that are both standardised and validated.
What to keep in mind
The review found substantial methodological heterogeneity, preventing quantitative synthesis; reliability reporting was also limited in the included studies.