Total knee arthroplasty has been performed even for severe valgus knee. All ligaments around knee must be balanced to obtain good clinical results. Especially medial collateral ligament plays a role as a stabilizer. For severe valgus knee, however, deep medial collateral ligament (dMCL) located closely to the articulating tibial surface [Fig. 1] can be damaged by bone resection in standard tibial osteotomy which may leads to progress valgus deformity. There are no report of dMCL preserved total knee arthroplasty for sever valgus knee. Thus it was evaluated the clinical outcomes of total knee arthroplasty for severe valgus knees using dMCL preservation technique.Background
Purpose
Proper initial fixation of the stem in the femoral canal is important to achieve successful long-term clinical results in total hip arthroplasty (THA) and bipolar hemiarthroplasty (BHA). However, this factor fully relies on surgeon's experience and skill during the hammering process. The goal of this study is to evaluate the frequency of the stem hammering sound which enables the achievement of proper stem fixation and avoiding femoral bone fracture. 57 patients who received BHA as a result of femoral neck fracture were evaluated. Intraoperative images of stem hammering were recorded using a digital video camera (Everio GZ-MG275, Victor, Japan). The frequency of the hammering sound was analyzed using a digital audio editor, GoldWave (GoldWave Inc.) (Figure 1). The frequency change during hammering was categorized into two groups, convergent and non-convergent, according to the frequency change pattern (Figure 2). The definition of “convergent group” is as follows: in the last five hammering sounds to finish the stem insertion, 1) Three consecutive hammering frequency shape and distribution 2) Formant peak frequency within the range of 3,000 Hz. Two types of cementless stems, SYNERGY SELECT II (tapered) and ECHELON TITANIUM (cylindrical, both from Smith & Nephew, Inc.) were used. Stem hammering was conducted using the same stem inserter. Canal Flare Index (CFI), Cortical Index (CI), Singh Index (SI), canal filling ratio, and the total number of stem-cortex contact zones were evaluated on x-ray images. The Mann-Whitney U-test was used for statistical analysis.Introduction
Materials and methods
