A 17-Year-Old Boy

and Iain McNamara¹

(1)

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

A 17-year-old boy presented with a long-standing history of problems with both legs culminating in a dislocating left patella in flexion. He was not sure of a specific first episode. He was still playing sports, notably soccer, on a regular basis and was able to cycle. However, his control of the left knee and ability to play sports were progressively deteriorating. He was otherwise fit and well and taking no medication. No one else in the family had a history of patellar dislocation.

Scores

Kujala	45
Beighton	6
BMI	21

Examination

He had a left unilateral fully correctable valgus of 10^°, with, clinically retroverted hip and an external tibial torsion of 10^°. There was no effusion. His VMO was present MRC grade power 5. He had no patellar apprehension. His mediolateral glide in extension was +. His patella dislocated in flexion. He had a full range of knee motion −10^°/−10^°/140^°. His tibiofemoral joint ligament examination showed an anterior drawer +, Lachman’s −, posterior drawer −, MCL −, and LCL ++.

Question 1

What images do you require to manage this problem surgically?

Images

CT Scan Measurements

Rotational profiles:
Femur	Right = 13^° internal rotation	Left = 4^° internal rotation
Tibia	Right = 20^° external rotation	Left = 20^° external rotation
CT patellar protocol:
Patellar tilt	Right = 8^°	Left = 13^°
TTTG	Right = 6 mm	Left = 7 mm

Question 2

What are the anatomical abnormalities that need correcting to get this patella to track straight?

Question 3

What are the details of the operation you would do to correct these abnormalities?

Question 4

What will you tell the patient of the expected outcome for this surgical intervention?

Operation Left Knee

Distal rotational osteotomy (Hinterwimmer et al. technique*), patelloplasty, Albee trochleoplasty, medial patellofemoral ligament reconstruction (semitendinosus autograft), and double-breasting medial reefing

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