Case 1 - History

This 55 y/o female had debilitating pain as a result of medial compartment osteoarthritis of the right knee. In December, 1994, she underwent tricompartmental, cemented total knee replacement with a lateral release.Her postoperative course was uneventful. Four weeks following surgery she began to complain of anterior knee pain located just proximal to the patella in the quadriceps tendon. She was begun on a course of physical therapy with quadriceps strengthening and stretching, ultrasound and hot/cold therapy.

Physical Exam


The patient was lying supine in no distress. The midline incision was well-healed. She had no observable swelling about the knee. The knee joint was minimally warm. There was no palpable knee effusion. The knee actively flexed from full extension to 124 degrees. The was no anteroposterior or mediolateral instability. The alignment of the knee was anatomic. The patella tracked normally. The patient was tender to deep palpation at the junction of the proximal patellar pole and the attachment of the quadriceps tendon. The patient demonstrated some pain upon arising from a chair and required assistance with her arms.

Which of the following tests would you perform?

CBC

ESR

Radiographs

MRI

Radionuclide scan

What is your differential diagnosis?


What is the most likely diagnosis?

Cannot answer
Infection
Femoral component loosening
Tibial component loosening
Patellar component loosening
Patellar subluxation
Quadriceps tendonitis
Quadriceps rupture

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Additional Questions for CME credit.....

1) Name some causes of anterior knee pain post TKA:

2) Name the best study to diagnose osteonecrosis of the patella:

3) Give the reason why osteonecrosis of patella occurs post TKA:

4) Name all the vessels that supply the patella and form the anastomotic ring:

5) Name the vessels that are divided during medial arthrotomy without lateral release:

6) What vessel is at risk when a lateral retinacular release is performed:

7) How can you avoid compromising the vessel in question # 6:

8) Why should you not aggressively debulk the fat pad?

9) What are the treatment options for patellar component loosening?

10) What are the treatment options for periprosthetic patellar fracture?

11) Which vessels become attenuated and less consistent after age 60 and may explain why patients over the age 60 have higher incidence of osteonecrosis the patella post TKA with lateral release?


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Submitted by:
Vahan Kilaghbian, M.D.
Jeffrey D. Reuben, M.D., PhD.
7\25\95

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