Salvage of severe knee osteoarthritis: efficacy of tibial condylar valgus osteotomy versus open wedge high tibial osteotomy

Abstract

Introduction To compare the clinical outcomes and the radiographic features between tibial condylar valgus osteotomy (TCVO) and open wedge high tibial osteotomy (OWHTO). New insight into the indication criteria for TCVO was also clarified for achieving satisfactory results. Materials and methods Sixty-three knees with medial-compartment osteoarthritis were retrospectively studied. Thirty-four knees with subluxated lateral joint and depression of the medial tibial plateau underwent TCVO and the rest underwent OWHTO. Among the 63 knees included, 27 knees with a pre-operative femorotibial angle (FTA) ≥ 185° were defined as severe varus (subgroup S, 15 in STCVO group and 12 in SHTO group). Lower limb alignment, intra-, and extra-articular congruency were evaluated according to the radiograph obtained before and 24 months after surgery. The visual analog scale (VAS) score and Hospital for Special Surgery (HSS) score were obtained to assess the clinical results. Opening angle and distance of the opening gap in each group were measured by intra-operative fluoroscopy. Results During the 2-year follow-up period, the mean HSS score increased from 70.3 to 81.4 in HTO group and 65.9 to 87.3 in TCVO group (p < 0.05). The mean VAS score decreased from 5.9 to 2.6 and 6.0 to 2.1, respectively (p < 0.01). Pre-operative FTA was restored to 172.9° in HTO group and 171.3° in TCVO group, and percentage of mechanical axis (%MA) was improved to 59.7% and 61.2%, respectively. Joint line convergence angle (JLCA) was slightly restored and medial tibial plateau depression (MTPD) was relatively the same before and after OWHTO, while these parameters improved greatly (from 6.4° to 1.2° and − 8.0° to 5.9°, p < 0.01) in TCVO group. More undercorrected knees were observed in SHTO group than STCVO group (58.3% and 13.3%, p < 0.05). Opening angle and distance of the opening gap were larger in TCVO group (19.1° and 14.0 mm) than those in OWHTO group (9.3° and 10.1 mm, p < 0.05). Conclusion Compared to OWHTO, TCVO had priority in treating advanced knee OA with intra-articular deformity. However, TCVO had a limited capacity to correct the varus angle. Besides, TCVO might be suitable for medial-compartment OA with a pre-operative FTA ≥ 185°.

Geometrical analysis of the opening gap after tibial condylar valgus osteotomy for proper hinge point selection

“…According to Paley's concept, for severe genu varum with intra-articular deformity, the performance of a corrective osteotomy at the level away from CORA requires the transverse movement of the distal bony fragment to align the proximal and distal axes of the relevant bone segments (24). As more gap-opening degrees are required for an angle correction than for OWHTO, the anatomy of the medial aspect of the proximal tibia undergoing TCVO displays the same pattern, but to a greater degree (5,8).…”

“…Tibial condylar valgus osteotomy (TCVO), a novel L-shaped osteotomy performed from the medial side of the proximal tibia to the intercondylar eminence, can adjust the congruity of the joint surface and improve intra-articular stability (5,6). TCVO has been reported to be an efficient technique for treating intra-articular deformity caused by degenerative arthritis (7,8), trauma (9), and growth disorders, such as Blount disease (5).…”

“…To avoid iatrogenic injury to the joint surface of the tibial plateau during TCVO, the following 3 points were chosen for the candidate hinge position: (I) the hinge set at the medial beak, (II) the center, and (III) the lateral beak of the intercondylar eminence. Wang et al showed that a larger gap opening angle was required in TCVO compared to OWHTO to correct the medial proximal tibial angle (MPTA) to the same extent (8). As TCVO can be regarded as a special form of OWHTO, with its hinge point positioned relatively medially, it was conjectured that the hinge position at the lateral part (i.e., the lateral beak of the intercondylar eminence) will result in a relatively smaller gap opening angle during TCVO (7,8).…”

“…Wang et al showed that a larger gap opening angle was required in TCVO compared to OWHTO to correct the medial proximal tibial angle (MPTA) to the same extent (8). As TCVO can be regarded as a special form of OWHTO, with its hinge point positioned relatively medially, it was conjectured that the hinge position at the lateral part (i.e., the lateral beak of the intercondylar eminence) will result in a relatively smaller gap opening angle during TCVO (7,8). This study sought to (I) conduct retrospective evaluations of patients undergoing TCVO to identify the preliminary relationship between the magnitude of the opening gap and the hinge positions; (II) develop a simple and effective geometric model for surgical simulation and mathematical description; and (III) verify the hypothesis that among the 3 candidate hinge points, the hinge point at the lateral beak of the intercondylar eminence leads to the smallest gap opening angle after TCVO.…”

Lateral Gradual Opening Osteotomy of the Tibia With Monolateral External Fixator for Correcting the Valgus Deformity of the Tibia

“…Acute correction has the advantage of being a single surgery, but there is a risk of fracture of the opposite cortex, hypercorrection, infection, or pseudarthrosis of the osteotomy focus. 14 , 15 , 16 , 17 , 18 , 19 , 20 When gradual correction is performed using a monolateral external fixator, the advantages include smaller surgical access site, partial osteotomy resulting in less postoperative pain, and the possibility of dynamic correction to avoid hypo- or hypercorrection. 21 …”