Surgery and Radiology Section

TREATMENT

• In bovines subcutaneous desmotomy of medial patellar ligament is the common surgical procedure to correct the upward fixation of patella. In western countries, this technique is known as Bassi’s method.
• It can be performed in standing animals, but it is safe to perform the surgery in lateral recumbency.

Preparation of animal

• The animal is cast with the affected limb lower most (ground side) and the other limbs are tied together.
• The affected limb is drawn backward and secured in position by two to three persons in such a way that stifle joint is extended completely. This makes the medial patellar ligament straight.

Identification of site

• For desmotomy in right limb, left hand should be used for identification and left limb right hand should be used.
• The thumb finger and middle finger should be kept on the medial and lateral tibial tuberosity projections.
• The index finger is kept above the thumb and middle finger with an equi distance imaginary triangle.
• The medial patellar ligament is palpated with the index finger by its prominence and stretch.
• Though the medial ligament is widely separated from the middle patellar ligament , it is not possible to appreciate the groove in between the ligaments due to adipose and fibrous tissues.

Surgical procedure

Open method

• A small incision is made in the skin directly over the medial ligament starting immediately in front of the medial tuberosity, towards the cranial tibial tuberosity.
• The index finger is passed into the wound and the skin is separated from the fascia all around the site.
• The fascia is dissected to expose white glistening medial patellar ligament.
• The ligament is exteriorized by passing a curved scissors or a tenaculum flat wise under the ligament from before backward.
• The ligament is then severed near its insertion using a tenotomy knife/ Bard parker blade No 12.
• The undivided fibers are severed with scissors after thorough exploration with index finger.
• The cutaneous/ skin wound is closed with one or two interrupted sutures.
• The sutures are removed on the seventh or eighth post operative days.
• Protrusion of adipose tissues through the gap created by the cut ends of the ligament, cessation of crunching sound and immediate relief of the characteristic jerky flexion during progression are indications of successful medial patellar desmotomy.

Closed method

• After identification of the site 2-3 ml of lignocaine is injected in front of the site for loss of sensation.
• The area is swabbed with antiseptic preferably povidone – iodine.
• An abscess knife, curved probe pointed knife, Hey –groove knife or Bard Parker blade No 12 is passed flat wise with its tip fixed underneath the ligament (V shaped groove) and the sharp edge of the instrument is directed towards the ligament.
• The ligament is then transected by withdrawing the knife towards the operator.
• A small quantity of tincture iodine is infused in to the wound.
• The wound is left unsutured.
• The limb is flexed and extended for several times for complete severing of the fibers which are undivided.
• Cessation of crunching sound and immediate relief of the characteristic jerky flexion during progression are indications of successful medial patellar desmotomy.