Lateral closing wedge high tibial osteotomy

OVERVIEW

Chapter synopsis

This chapter discusses the indications and contraindications for high tibial osteotomy (HTO) and highlights when a lateral closing wedge (LCW) may be preferable over a medial opening wedge (MOW). Our LCWHTO surgical technique is presented as well as a summary of published outcome data.

Important points

Opening and closing wedge HTOs simultaneously alter coronal and sagittal alignment.
LCWHTO has a tendency to reduce tibial slope and increase patellar height.
MOWHTO has a tendency to increase tibial slope and decrease patellar height.
Revision anterior cruciate ligament (ACL) reconstruction in the setting of genu varum and increased tibial slope is the most common indication for LCWHTO in our practice.
When a valgus producing HTO is indicated, patella baja, ACL deficiency, obesity, and limb length discrepancy (long operative limb) are relative indications for a LCWHTO over MOWHTO.

Clinical/surgical pearls

Meticulous pre-operative templating on high-quality long leg alignment films is critical.
To prevent metaphyseal-diaphyseal mismatch after closing the osteotomy, the two converging guide pins should be equidistant to the hinge point creating an isosceles triangle.
After the osteotomy wedge is removed; a Kerrison rongeur is helpful to safely remove residual posterior bone.
Adequate release of the proximal tibiofibular joint (or potentially consider perfomorming a fibula osteotomy) is required to close down the osteotomy.
Drilling the medial cortical hinge with a K-wire can aid plastic deformation of the medial hinge whilst closing the osteotomy.
If a two-stage revision ACL reconstruction is being performed, the removed bone wedge can be used to graft the ACL tunnels.

Clinical/surgical pitfalls

Adequate patient education and expectation setting is critical.
Caution must be taken to protect posterior neurovascular structures at all times.
Inadequate release of the proximal tibiofibular joint is a common reason the osteotomy will not close down.
In the setting of combined ACL reconstruction, never pass the ACL graft before placing all screws into the plate.
Looking up the ACL tibial tunnel with the arthroscope can confirm there is no screw-tunnel conflict before graft passage.
A medial staple should be considered in the event of fracture of the medial hinge.

Video available

Video 77.1: Lateral closing wedge high tibial osteotomy.

Introduction

Osteotomy is a powerful tool to optimize alignment and load distribution in the treatment of knee pain and/or instability. Osteotomies for knee pathology can be performed above or below the joint and are most commonly opening or closing wedges, although other types such as dome, intra-articular, and tibial tubercle osteotomies exist. The medial opening wedge high tibial osteotomy (MOWHTO) is the most common tibial-sided osteotomy in our practice. However, the more technically demanding lateral closing wedge high tibial osteotomy (LCWHTO) has an important role in selected circumstances. LCWHTO is advantageous in the setting of revision anterior cruciate ligament (ACL) reconstruction with associated proximal tibia vara and increased tibial slope. When a valgus producing HTO is indicated, patella baja, ACL deficiency, obesity, and limb length discrepancy (long operative limb) are relative indications for a LCWHTO over MOWHTO. Importantly, a coronal plane correction with a proximal tibial osteotomy also affects the sagittal plane due to the triangular cross-section of the tibial metaphysis. A MOWHTO is actually an anteromedial opening wedge producing valgus with medial opening and increasing tibial slope with anterior opening. An LCWHTO is actually an anterolateral closing osteotomy, producing valgus from the lateral closing and reducing tibial slope with anterior closing. This sagittal plane alteration is critical to consider when there is coexisting cruciate ligament deficiency. Reducing excess tibial slope is advantageous in ACL deficiency and increasing tibial slope is advantageous with posterior cruciate ligament (PCL) deficiency.

Preoperative considerations

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