Clin Orthop Surg.  2010 Dec;2(4):232-236. 10.4055/cios.2010.2.4.232.

Preventing Lateral Skin Numbness after Medial Unicompartmental Knee Arthroplasty

• Song MH
• Kim BH
• Ahn SJ
• Yoo SH
• Shin SH

• KMID: 1719324
• DOI: http://doi.org/10.4055/cios.2010.2.4.232

Abstract

BACKGROUND
The authors report the results of preserving the infrapatellar branch of the saphenous nerve during unicompartmental knee arthroplasty to prevent lateral skin numbness.
METHODS
All 100 cases had medial compartmental osteoarthritis and a minimally invasive technique had been used. The mean follow-up duration was two years and eight months (range, 24 to 42 months).
RESULTS
The classification according to the location of this nerve was observed as either Mochida Type I with 76 cases (76%), Type II with 16 cases (16%), and unclassified type with 8 cases (8%). In Type I, the nerve was saved in 62 cases (82%), but could not be preserved in Type II because of the surgical procedure. These results showed that the mean distance from the joint line to the nerve of Type I was 9.13 mm (range, 4 to 15 mm) and the nerve passed inferiorly.
CONCLUSIONS
This study showed the location of this nerve can be predicted ahead of the procedure, which will help preserve it during the surgery.

Keyword

Lateral skin numbness; Infrapatellar branch of saphenous nerve

MeSH Terms

Aged
Aged, 80 and over
Arthroplasty, Replacement, Knee/adverse effects/*methods
Female
Humans
Hypesthesia/etiology/*prevention & control
*Knee Prosthesis
Male
Middle Aged
Osteoarthritis, Knee/surgery
Skin/*innervation

Figure

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  Fig. 1 Typical type I, in which the nerve crosses the joint line.

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  Fig. 2 Perform the medial arthrotomy carefully.

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  Fig. 3 Place the nerve just below the tibial saw guide.

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  Fig. 4 Removing the resected tibial plateau.

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  Fig. 5 Prepare the femoral condyle.

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  Fig. 6 Implant all the component.

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  Fig. 7 The nerve was well preserved after the operation.

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  Fig. 8 Distribution patterns of the infrapatellar branch of the saphenous nerve.

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  Fig. 9 The typical distribution of skin numbness after right medial unicompartmental knee arthroplasty.

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