Page 80 - Manual of Equine Field Surgery

CHAPTER 12

Medial Patellar Desmotomy

Joanne Kramer

INDICATIONS maximal stifle extension the fibrocartilage is ele-

vated and rotated over the medial trochlear ridge

Horses with persistent upward patellar fixation or of the femur' (Figure 12-2). The patella is released

horses with continued intermittent upward patel- when the patella is rotated laterally and elevated

lar fixation after appropriate conditioning and slightly by the quadriceps to clear the medial

maturation have been achieved ( Figure 12-1). trochlear ridge. The locked and unlocked posi-

tions of the patella are shown in Figures 12-1

through 12-4.

EQUIPMENT

A blunt-tipped bistoury knife is used to transect PROCEDURE

the medial patellar ligament.

With the limb fully weight bearing and the

I
POSITIONNG AND PREPARATION stifle extended, a 2-cm vertical skin incision is
made just cranial to the distal part of the medial

patellar ligament (Figure 12-5). Curved Kelly
Surgery is performed with the horse standing. The forceps are advanced under the medial patellar

limb should be fully weight bearing with the stifle ligament to create a plane of dissection deep to the

extended. The tail should be wrapped and tied out medial patellar ligament. Keeping close to the

of the surgical field. The medial aspect of the stifle medial patellar ligament and on its distal aspect,

region is clipped and prepared aseptically. Local a bistoury knife or Bard Parker handle with a new

anesthetic is injected subcutaneously cranial and No. 10 blade is advanced under the medial patel-

deep to the medial patellar ligament,
lar ligament with the cutting side facing distal.

When the tip of the blade or bistoury knife is pal-

pable on the caudal side of the medial patellar lig-
ANATOMY

ament, the instrument is rotated 90 degrees and

the medial patellar ligament is severed (Figure 12-

The medial patellar ligament inserts distally in a 6). W11en the ligament is transected, the stifle will

groove on the proximal medial aspect of the tibial flex slightly. After transection, the aponeurotic

tuberosity and proximally on the medial aspect of insertion of the sartorius muscle is palpable just

the patella through the parapatellar fibrocartilage. caudal to locatio11 of the patellar ligament. 2·4 The

Upward fixation of the patella occurs if during skin is closed with interrupted sutures.

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