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Case Reports
. 2021 Apr 23:33:100481.
doi: 10.1016/j.tcr.2021.100481. eCollection 2021 Jun.

Unusual total knee immobilization in an elderly patient due to inferior patella dislocation: Case report and review of the literature

J Zimmermann  1 , P Grüninger  1 , A Babians  1 , U Zingg  1
Affiliations
Case Reports

Unusual total knee immobilization in an elderly patient due to inferior patella dislocation: Case report and review of the literature

J Zimmermann et al. Trauma Case Rep. .

Erratum in

Abstract

Inferior dislocation of the patella is a rare cause of a blocked knee and occurs typically in elderly patients. In most cases the mechanism is an osteophyte on the superior pole of the patella that becomes entrapped into the femoral trochlea, keeping the patella horizontally rotated and inferior localized. Advanced age and osteoarthritic changes of the knee are the main risk factors. Reduction should be performed under general anesthesia. We describe a case of an elderly lady with a type II inferior patella dislocation after direct blunt trauma. The therapy entailed reduction, knee arthroscopy, arthroscopic resection of osteophytes and smoothening of the articular surface. No recurrence occurred and range of motion was satisfactory at time of follow-up.

Keywords: Geriatric trauma; Knee immobilization; Patella dislocation.

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Conflict of interest statement

The authors have no relevant financial relationship or conflict of interests to disclose.

Figures

Fig. 1
Fig. 1
Preoperative findings: Severely destroyed osteoarthritic knee with low bone density in the anterior-posterior (a.p.) view (a). Impacted superior pole of the patella on the lateral X-Ray view (b). Findings on the MRI (c, d) with intact quadriceps tendon.
Fig. 2
Fig. 2
Intraoperative lateral X-Ray: a.) After reduction b.) In 60° flexion c.) In 90° flexion d.) In 110° flexion. Large defect zone at the femoral trochlea (green arrow) and the fractured osteophyte from the superior pole of the patella (yellow arrow). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 3
Fig. 3
a: Arthroscopic view: There is an articular edge (black arrow) at the superior border of the defect zone. b: Arthroscopic view: Compression of the osteoporotic bone with a blunt chisel after shaving of the articular edge of the femoral trochlea.
Fig. 4
Fig. 4
8 weeks postoperative clinical examination: Knee flexion of 90° was similar on both sides.
Fig. 5
Fig. 5
8 weeks postoperative a.p. and lateral X-Ray: The shaved and compressed area is marked with a black arrow.
See this image and copyright information in PMC

References

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