Abstract
Purpose This study was carried out to compare the alteration in skin sensation following midline, medial and short medial incisions for knee replacement.
Method 88 patients with 102 knees were examined for altered skin sensation over the front of the knee, all were at least 18 months from their knee replacement. Twenty-one knees had a medial incision, 38 a midline incision and 43 a short medial incision for UKR.
A scale of −2 to +2 was used to measure different degrees of skin hypo or hyperaesthia. A purpose-designed grid, designed to fit different knee sizes, was used to record sensations. A computer programme was created to record all patients’ data including the length and shape of the incision in relation to anatomical landmarks.
A parallel histological study was carried out on 12 skin specimens taken from the 2 standard incisions. The specimens were prepared and stained for nerve endings. The number of nerve endings in each incision was calculated.
Results The average length for the medial incision was 17 cm with an average post-operative time of 3.37 yrs and skin numbness of 87.78 cm square.
The midline incision average length was 17.85 cm with an average post-operative time of 4.7 yrs and a numb area of 73.7 cm square.
The short medial incision used for UKR averaged to be 9 cm in length with an average post operative time of 3.9 yrs and an area of numbness of 48.1 cm square.
Histologically less cutaneous nerve endings were seen in specimens from midline incisions than medial incisions.
Discussion The midline line incision seems to produce less dermal parasthesia than the medial incision, this probably relates to both the wound position and the density of nerve endings. The length of the incision correlated with the area of numbness when comparing the short and long medial incisions.
Correspondence should be addressed to Roger Smith, Honorary Secretary, BASK c/o Royal College of Surgeons, 35 – 43 Lincoln’s Inn Fields, London WC2A 3PN
