Changing regularity of articular function in the slow lengthening process of limbs

Xuquan WANG; Qihong LI; Jianzhong XU; Shuzhi MA; Xuehui WU

ABSTRACT

BACKGROUND:

As reported in some literatures, articular dysfunction following limb lengthening is one of the commonest complications, but some scholars believe that the articular dysfunction after lower limb lengthening is avoidable providing appropriate technical operation and effective function prevention.

OBJECTIVE:

To investigate the changes of articular function of knee during limb lengthening in rabbits so as to provide a experimental basis for clinical tasks.

DESIGN:

A randomized controlled trial

SETTING:

Department of Orthopeadics, Affiliated Hospital of Some Military Medical University.

PARTICIPANTS:

Study was conducted in the Experimental Animal Center of the Third Military Medical University of Chinese PLA from February 2001 to June 2002. Totally 30 healthy adult New Zealand rabbits obtained from the Experimental Animal Center of the Third Military Medical University of Chinese PLA were randomly divided into lengthening group and delayed observation group(observed at 3 months after the stop of lengthening).

METHODS:

Every group was further divided into three sub-groups according to distraction range 10%, 20% and 40%. Upper-tibia metaphysis distraction was adopted at the rate of 1 mm per day . Distraction and iconography changes of knee joint were observed with X-ray. The motive range of knee was investigated at the end of distraction and three months later.MAIN OUTCOME

MEASURES:

Articular motive range of the knee before the distraction, at the end of distraction and three months later, X-ray resutls

RESULTS:

① There was no obvious radiographic change in knee at every time point in each group. ② Significant flexion disorder in knee was found in 20% distraction subgroup( P ＜ 0. 05), which was only 44. 7% of normal motive range in 40% distraction subgroup( P ＜ 0. 01) . Motive functions of knee in delayed observation group were significantly improved; thereinto,20% distraction subgroup returned to preoperative level, while 40% distraction subgroup also had significant improvement compared with that of 3 months earlier but still lower than normal level, which was only about 88.5% of normal level( P ＜ 0.05).

CONCLUSION:

Temporary articular dysfunction might occur during limb lengthening process, and mostly during big range of distraction. Although the dysfunction could be gradually recovered after the stop of lengthening, active prevention is still necessary.