Medial Opening Wedge HTO

 

 

Puddhu plateArthrex Contour Lock Tomofix

 

Medial opening wedge osteotomy

 

OW HTOOW HTO

 

Equipment

 

Arthrex Locking Puddhu plate PDF

 

Arthrex ContourLock system PDF

 

Synthes Tomofix PDF

 

Technique

 

Vumedi uniplanar Arthrex Puddhu plate technique

 

Vumedi uniplanar Arthrex Puddhu plate technique

 

Vumedi biplanar medial opening wedge

 

Vumedi biplanar medial opening wedge

 

Position

- patient supine on radiolucent table

 

Approach

- medial incision close to midline to incorporate into later TKA

- between tibial tuberosity and MCL

- L shaped incision of sartorius fascia

- identify and elevate pes anserinus, as may have to slide plate under

- identify and elevate MCL posteriorly

 

HTO approachHTO approach

 

HTO approachHTO approach

 

Exposure

- must expose and protect entire posterior tibia subperiosteally

- should be able to place finger entirely across tibia to proximal tibio-fibular joint

- must expose and protect patella tendon above tibial tuberosity

- place Langenbeck / Homan retractors anteriorly and posteriorly

 

Consider lateral hinge 2 mm K wire

- 10 mm from lateral cortex

- distal to proximal

 

Oblique Osteotomy

- entry is 4 cm distal to joint line

- osteotomy must pass above tibial tuberosity

- aiming for proximal third of the fibula head

- to 10 mm of lateral cortex to avoid lateral hinge fracture

- stay 2 cm below the tibial plateau to avoid intra-articular fracture

- ensure osteotomy is parallel to joint line to avoid altering slope

- ensure complete posterior cortex

 

HTOPosterior slope

Guide pins for osteotomy and checking posterior slope

 

HTO OsteotomyHTO osteotomy

Osteotomy to within 1cm of the lateral cortex

 

Opening of wedge

- slow

- stacked osteotomes / lamina spreader / wedged osteotomes

- ensure no change of posterior slope on lateral

 

HTO osteotomy openingHTO WedgesHTO osteotomy

Arthrex wedged osteotomes

 

HTO laminer spreader

Opening osteotomy with laminar spreader

 

Check correct alignment with drop rod

- goal lateral tibial spine

- Fujisawa point / 62% of the tibial plateau / lateral tibial spine

 

HTO droprod

 

Stabilisation

- locking plates

- +/- autograft / allograft / synthetic bone graft

 

Puddhu platePuddhu platePuddhu platePuddhu plateHTO Lateral Xray

Arthrex Locking Puddhu plate PDF

 

Contour LockArthrex Contour Lock Synthes Contour Lock

Arthrex ContourLock system PDF

 

Synthes TomofixSynthes TomofixSynthes Tomofix

Synthes Tomofix PDF

 

Biplanar medial opening wedge osteotomy

 

Biplanar medial osteotomy

 

Retro-tubercle osteotomy

 

Advantage

- preserves patella tendon

- ? increases bony contact for healing

 

Disadvantage

- ? increases incidence of lateral hinge fracture

 

Complications

 

Infection 1%

Lateral hinge fracture 25%

Intra-articular fracture 3%

Delayed / nonunion

Compartment syndrome

 

Infection

 

Hancock et al KSSTA 2024

- database of 822 osteotomies around the knee

- overall infection rate 2.8%

- superficial infection 1.6%

- deep infection 1.2%

- all successfully treated with debridement +/- plate removal

 

Lateral hinge fracture

 

HTO Allograft

Type I hinge fracture

 

Definition

 

Extension of the osteotomy into far cortex

May be associated with instability / delayed union / nonunion

 

Incidence

 

Lee et al Arthroscopy 2018

- 48 opening wedge HTO

- xray: incidence lateral hinge fracture 15%

- CT: incidence lateral hinge fracture 50%

 

Causes

 

Kim et al Arthroscopy 2021

- systematic review hinge fracture after OW HTO

- incidence 25%

- increased with opening > 11 mm

 

Kim et al Arthroscopy 2024

- 55 lateral hinge fracture

- Type I associated with lateral distance < 6 mm

- Type II associated with lateral distance > 9 mm

 

Classification lateral hinge fracture after OW HTO

 

Takeuchi

 

Takeuchi classfication

- type I: extend into lateral cortex above proximal tibio-fibular joint

- type II: extend into lateral cortex below proximal tibio-fibular joint

- type III: extend into lateral tibial plateau

 

HTO hingeHTO hinge

Type II hinge fracture

 

Delayed union / Nonunion

 

Nakamura et al Bone Joint J 2015

- 15 HTO with lateral hinge fracture

- increased delayed union with Type II

- increased delayed union / loss of position with Type III

 

Song et al Arch Orthop Trauma Surg 2020

- 132 OW HTO

- 24% incidence lateral hinge fractures

- time to union no hinge fracture: 5 months

- time to union hinge fracture: 7 months

- no difference in outcome

 

Prevention

 

10 mm from lateral cortex

Aim for tibio-fibular joint

Slow correction

Lateral 2 mm K wire - inserted distal to proximal 10 mm from lateral cortex

? Biplanar osteotomy

 

Gulagaci et al KSSTA 2020

- 206 OW HTO, 71 had lateral K wire

- no K wire: hinge fracture 40%

- K wire: hinge fracture 17%

 

Nha et al KSSTA 2020

- 59 uniplanar osteotomy versus 44 biplanar osteotomy

- uniplanar osteotomy: hinge fracture 12%, plate irritation 19%

- biplanar osteotomy: hinge fracture 27%, plate irritation 32%



Management

 

Type I:  limit weight bearing 6 weeks

Type II / displacement: lateral plate

 

Instability

- place a Richards staple / plate over lateral fracture site

 

Intra-articular fracture

 

HTO Closing Wedge Intra-articular fractureHTO intraarticular fracture

 

Incidence

 

Martin et al AJSM 2014

- 323 OW HTO

- intra-articular lateral tibial plateau fractures 3%

 

Causes

- proximal fragment too thin

- osteotomy too short / trying to preserve far cortex for stability

 

HTO Opening Wedge Puddhu Plate

Osteotomy too close to articular surface

 

Prevention

- proximal fragment minimum 15 mm thick

- osteotomy within 10 mm of far cortex

- slow correction to allow stress relaxation

- ? keep in proximal K wires

 

HTO #HTO intraarticular fractureHTO #HTO 4

 

Non union

 

Bone grafting and locking plates

 

Lash et al Arthroscopy 2015

- systematic review of 3000 OW HTO

- autograft: delayed / nonunion 2.6%

- allograft: delayed / nonunion 4.6%

- synthetic bone graft: delayed / nonunion 4.5%

- non locking plates: delayed / nonunion 3.7%

- locking plates: delayed / nonunion 2.6%

 

Other

 

Undercorrection /  loss of correction

DVT/PE

Patella baja

Compartment syndrome

Harware removal