A 22-Year-Old Woman

and Iain McNamara¹

(1)

Trauma & Orthopaedics, Norfolk & Norwich University Hospital, Norwich, United Kingdom

A 22-year-old woman presented with problems with both knees. On the right, she had recurrent patellar dislocation, and on the left, the patella was dislocated throughout knee flexion. The left knee was the main problem and had been worsening over the previous 4 years. She had her first dislocation when she was 15 years old and a subsequent arthroscopic lateral release aged 18 years old. The knee was painful and swollen. There was no family history of patellar dislocation. Her Kujala score was 16.

Examination

She had Marfanoid features and her Beighton score was 4 out of 9. She walked with a limp.

She had slight varus alignment with an intercondylar distance of 1 cm. She had no internal rotation at the hip with 80° external rotation. Her tibial torsion was 0°. There was no effusion in the knee, the VMO was absent, the mediolateral glide in extension was +++, and there was no patellar apprehension. She had a full range of knee movements with a 5° quadriceps lag. The patella tracked laterally throughout knee movement. There was a prominent trochlear boss.

Question 1

What do you think is the likely management from this information and why?

Images

The boss height measured 5 mm and the patellar height 1.2

Question 2

What is the Dejour grade for each knee?

Question 3

Where is the left patella likely to show evidence of wear?

Operation

Left deepening trochleoplasty, MPFL reconstruction, lateral release, and patelloplasty.

At operation the findings were a significant trochlear dysplasia with fibrillation of the medial patellar facet. The latter was microdrilled. After the trochleoplasty the tight retinaculum was released into the vastus lateralis muscle. To control patellar tracking, this was followed by an MPFL reconstruction using a free gracilis tendon graft.

Question 4

Why did she need an extended lateral release?

Follow-Up 6 Weeks Post-operation

Six weeks following her operation, she was doing very well, walking normally without crutches. She had not quite achieved quads control and was not ready to have the contralateral side operated on.

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