High tibial osteotomy: evolution of research and clinical applications--a Canadian experience.
OBJECTIVE
This narrative review describes experiences at the Fowler Kennedy Sport Medicine Clinic (FKSMC) with high tibial osteotomy (HTO) for patients with varus gonarthrosis, with particular focus on research published from the unit that has guided practice.


METHODS
The goals of surgery are to improve alignment of the weight bearing axis of the lower limb to lessen the load on the medial tibiofemoral compartment and thereby decrease these important risk factors for disease progression. The overall aims are to improve knee function and delay or even prevent the eventual need for arthroplasty. To achieve these aims, a medial opening wedge osteotomy is utilised, deliberately avoiding an over correction of the lower limb, but tailoring the angle of correction to an individual patient's characteristics. With such an approach, patients with a broad range of characteristics (including age, BMI and lateral compartment involvement) can benefit from the procedure. In addition, the HTO can be used with concomitant procedures to address specific presentations, such as large deformities and instability.


RESULTS
The results suggest that correction to a slight valgus alignment produces approximately 50% reduction in medial compartment loads during gait with large, clinically important improvements in patient-reported outcomes at 2-years postoperatively. In patients with substantial bilateral varus deformity, unilateral surgery can lead to increased dynamic knee joint loads on the nonoperative limb after surgery. This means that such patients require the close monitoring of both limbs and consideration of a staged, bilateral procedure if necessary. In patients requiring bilateral surgery, similar results after bilateral HTO to those after unilateral surgery have been reported. For patients requiring large corrections, the need for a concomitant tibial tubercle osteotomy to reduce the potential for iatrogenic patella infera is considered. Finally, HTO procedures can also be used in patients with instability, either to alter both sagittal and coronal alignment to correct instability in complex ligament deficiencies or to undertake simultaneous HTO and ACL reconstruction.


CONCLUSIONS
HTO is being used both alone and in conjunction with concomitant procedures with good clinical results. While continued investigation into patient selection and outcomes are required, current research indicates that HTO offers at least a partial solution for the patient with varus gonarthrosis to prolong the life of their native knee joint.


METHODS
V.
Fowler Kennedy Sport Medicine Clinic, Western University, London, ON, Canada. iainmcnamara@gmail.com
I
I
McNamara
T B
TB
Birmingham
P J
PJ
Fowler
J R
JR
Giffin
D001696:Biomechanical Phenomena; D002170:Canada; D005684:Gait; D056304:Genu Valgum / Q000150:complications / Q000601:surgery*; D056305:Genu Varum / Q000150:complications / Q000601:surgery*; D006801:Humans; D007593:Joint Instability / Q000209:etiology / Q000601:surgery*; D007719:Knee Joint / Q000502:physiology / Q000503:physiopathology / Q000601:surgery*; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D013977:Tibia / Q000601:surgery*; D016896:Treatment Outcome; D016474:Weight-Bearing