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Valgus Knee(Ⅲ) Coronal Plane Z­plasty in Lateral Approach

03. 17, 2020

Valgus Knee(Ⅲ) Coronal Plane Z­plasty in Lateral Approach 

For  severe  valgus  knee deformity, advantages of the anterolateral procedure are: (1) the lateral release, most usually necessary in valgus knees, is part of the approach. In the alternative case of medial arthrotomy, the vascular supply of  the  extensor  mechanism  is  seriously  impaired;  (2)  the  lateral  approach facilitates the release of the lateral contracted elements, offering better surgical view; and (3) the possibility to medicalize the tubercle, if required, improving this way the patellar tracking. 

Keblish’s lateral approach comprises of 6 steps:
Step Ⅰ. I­T Band Release or Lengthening
Step Ⅱ. Lateral Arthrotomy­ Coronal Plane Z­plasty
Step Ⅲ. Patella Dislocation­Joint Exposure
Step Ⅳ. Tibial Sleeve Release­ Osteoperiosteal
Step Ⅴ. Femoral Sleeve Release­ Osteoperiosteal

Step Ⅵ. Soft Tissue(Prosthetic Joint) Closure

Coronal Plane Z­plasty:

Valgus Knee(Ⅲ) Coronal Plane Z­plasty in Lateral Approach

The course of the lateral parapatellar incision begins  2­4cm lateral to the patella and
extends distally into the mid­portion of Gerdy’s tubercle (Fig.4.29), preserving the fibrous
layer, which joins  with the patellar tendon sheath anteriorly. Proximally, the incision
extends into the central quadriceps tendon.

Valgus Knee(Ⅲ) Coronal Plane Z­plasty in Lateral Approach


The superficial layer of the retinacular is separated from the deep layer with a coronal

plane Z­plasty, from superficial lateral to deep medial. The VL tendon is  substantially
thick (6­10mm) and allows for a horizontal (coronal) plane expansion release. The VL
tendon incision begins  near the musculo­tendonous  junction and ends  at the mid

coronal plane of the patella insertion.

Valgus Knee(Ⅲ) Coronal Plane Z­plasty in Lateral Approach


The mid­portion (lateral retinaculum) separates naturally from the deep capsule and fat pad.

Valgus Knee(Ⅲ) Coronal Plane Z­plasty in Lateral Approach

The capsule is  incised from the patella rim. The fat pad incision continues
obliquely to the intermeniscal ligament, retaining about 50% of the fat pad with the
patella tendon and 50% with the lateral sleeve, which includes  the lateral

meniscus rim for increased soft tissue stability.

Soft Tissue (Prosthetic Joint) Closure:

Soft  tissue  closure  is  completed  with  the  knee  flexed.  The  expanded  lateral soft tissue sleeve (coronal Z­plasty) is positioned to the medial sleeve. Towel clips or stay sutures are utilized, and the knee is extended and flexed through the maximum range. Distal to proximal closure is recommended.

Valgus Knee(Ⅲ) Coronal Plane Z­plasty in Lateral Approach

Distally, anatomic  reattachment of the I­T band and posterolateral sleeve to
Gerdy’s tubercle and the medial sleeve stabilizes the posterolateral corner. In the
mid­segment, the capsule is  sutured to the lateral border of the retinaculum.
Proximally, the vastus  lateralis  tendon is  reattached in the expanded (coronal
plane Z­plasty) position with the knee in maximal flexion. The knee is ranged to a
full flexion position (140 to 150 degrees), and soft tissue compliance and integrity
of the joint seal are checked. Appropriate adjustments or reinforcing sutures can
be implemented at this  time. The preoperative noncompliant­deforming lateral
soft tissue structures  are now more compliant and allow for coverage of the
prosthetic joint.