The presence of an intermediate tendon connecting the two patellar parts was only described by Petty .
We present a traumatic rupture of an intermediate tendon in a 47-year-old patient with horizontal patellar duplication.
The diagnosis of an intermediate tendon rupture in a duplicate patella was stated.
The main surgical options are excision of the small fragment and tendon reinsertion into the remaining patellar part, rigid fixation of both parts in order to achieve bone healing, or anatomical repair of the intermediate tendon.
This case report is the first description of an intermediate tendon rupture in a patient with horizontal patellar duplication, treated with an anatomical repair.
Petty reported a similar case in 1925, with rupture of an intermediate tendon in a horizontal duplicate patella .
The presence and nature of the intermediate tendon were also not reported.
The need for complementary imaging is mandatory to diagnose the extensor mechanism rupture and identify an intermediate tendon in a patient with a painful double patella.
We should think of a double patella with intermediate tendon rupture in all cases when the two separated patellar fragments are atypical.
SUMMARY: The digastric muscle is formed by two muscle bellies: one anterior and one posterior, joined by an intermediate tendon. It is localized in the anterior cervical region.
These are joined together by an intermediate tendon that passes through a fibrous sling that is attached to the body of the hyoid bone (Lockhart et al., 1983).
Case 2 presented bilateral variation, with the presence of two supernumerary bellies that originated medially to the digastric fossa of the mandible, with insertion in the contralateral intermediate tendon (Fig.