MOWHTO with locking plate guaranteed higher level of activity than mUKA in knee osteoarthritis

High tibial osteotomy (HTO) and medial unicompartmental knee arthroplasty (mUKA) are accepted treatment for medial knee osteoarthritis (OA).The article has been published in the ‘The knee’ journal.

Screpis et al conducted a study to compare results after Medial Opening Wedge HTO (MOWHTO) and UKA in a matched population of patients older than 50 years.

Indications for MOWHTO were: medial compartment OA (Kellgren & Lawrence (KL) 5 with a Medial proximal tibial angle (MPTA) < 840, a stable knee or stabilizable knee with additional concomitant procedures, full extension and at least 1200 of flexion.

Indications for UKA were: symptomatic medial compartment OA associated with good status of PF and lateral tibio-femoral compartments (including mild asymptomatic OA), stable knee, full extension and at least 1200 of flexion, HKA < 150 with completely or partially reduceable varus and a joint lane convergence angle (JLCA > 20).

A retrospective analysis searching for patients older than 50 years meeting indication both for UKA and MOWHTO was performed. A propensity score matching (PSM) based on demographics and clinical data was performed. Tegner activity scale (TAS), Lysholm knee score (LKS) and numeric rating scale for pain (NRS) were recorded prospectively prior to surgery, at 6 months and after a minimum of 4 years.

Key findings of the study were:

• 64 UKA and 71 MOWHTO were found.

• Mean follow up was similar (54.05 ± 4.80 and 52.62 ± 3.91).

• A significant improvement was found in both groups for all outcomes at 6 months and at final follow up.

• PSM yielded 29 pairs.

• Patients treated with MOWHTO showed superior TAS scores at 6 months (3.41 ± 0.50 vs 3.10 ± 0.56; p < 0.05) and at final follow up (3.83 ± 0.80 vs 3.27 ± 0.59; p < 0.005).

• NRS and LKS were comparable between groups.

• No major postoperative complications were reported, either during the perioperative period and at last follow up. Only one patient in the UKA group complained moderate persisting knee pain 28 months after surgery, without signs of radiographic migration or signs of PJI. No cases of DVT nor peroneal palsy were reported in either group. No UKA showed signs of radiographic migration during follow up. No suspected or diagnosed infections were reported.

The authors commented - “In conclusion, our study demonstrated that MOWHTO performed with locking plate and accelerated rehabilitation program is safe and effective also in advanced age patients with moderate medial OA and consistent articular damage. Patients reached higher activity level after MOWHTO than after UKA, with comparable functional scores and pain relief. Although excellent results and high rates of patients reported satisfaction were reached both after UKA and MOWHTO, it should be reasonable to consider the less demolitive surgical act as the first line of therapy."

Level of evidence: III

Further reading:

Higher activity level after opening wedge high tibial osteotomy compared to medial unicompartimental knee arthroplasty in a selected cohort of advanced age: A propensity score-matched analysis, D. Screpis, G. Piovan et al, The Journal of Arthroplasty 37 (2022) 1074-082,https://doi.org/10.1016/j.knee.2022.11.006