Musculoskeletal case 22. Presentation
=====================================

* Ciaran Keogh
* William C. Torreggiani
* Khalid Al-Ismail
* Peter L. Munk

A 17-year-old girl complained of recurrent episodes of pain and associated instability of both knees. She had no medical history, but her father, whom she described as having a lifelong limp, had recently begun dialysis for renal failure. On examination the patient had hypoplastic, ridged thumbnails and small, barely palpable patellae. The following radiographs were obtained: a straight anteroposterior view of the left knee (Fig. 1), a skyline view of both knees (Fig. 2) and an anteroposterior view of the pelvis (Fig. 3).

![FIG. 1](http://canjsurg.ca/https://www.canjsurg.ca/content/cjs/45/3/205/F1.medium.gif)

[FIG. 1](http://canjsurg.ca/content/45/3/205/F1)

FIG. 1 

![FIG. 2](http://canjsurg.ca/https://www.canjsurg.ca/content/cjs/45/3/205/F2.medium.gif)

[FIG. 2](http://canjsurg.ca/content/45/3/205/F2)

FIG. 2 

![FIG. 3](http://canjsurg.ca/https://www.canjsurg.ca/content/cjs/45/3/205/F3.medium.gif)

[FIG. 3](http://canjsurg.ca/content/45/3/205/F3)

FIG. 3 

What is your diagnosis?

For the answer and a discussion see page 228.

## Footnotes

*   Section Editor: Peter L. Munk, MD

*   Inquiries about this section should be directed to Dr. Peter L. Munk, Professor, Department of Radiology, Vancouver General Hospital and Health Sciences Centre, 855 West 12th Ave., Vancouver BC V5Z 1M9; plmunk{at}interchange.ubc.ca