Page 33 - ISAKOS 2019 Newsletter Vol II

We focused on the difference in the medial component gap and grouped the patients into three categories: the loose medial knee group (those with a difference in the medial component gap of >3 mm), the stable medial knee group (those with a difference of between ≥0 mm and ≤3 mm), and the tight medial knee group (those with a difference of <0 mm).
There were no significant differences between the stable medial knee group and the loose medial knee group in terms of preoperative demographic data or postoperative radiographic alignment. The numbers of medially stable knees and medially loose knees were 62 (80.5%) and 15 (19.5%), respectively. There were no knees in tight medial knee group. There were no knees with a negative component gap on either the medial or lateral side in extension or flexion. There were no knees with a smaller lateral component gap than medial component gap in either extension or flexion.
Our technique provided a relatively high proportion of medially stable knees. Generally, the resection level of the distal part of the femur affects the extension gap, whereas that of posterior part of the femur affects the flexion gap. The resection level of the proximal part of the tibia affects both gaps. Our technique can make it easier to balance the medial gap between extension and flexion without ligament release and can better maintain the joint line compared with the conventional measured resection or gap-balancing techniques.
Principles of Our Technique
1 Maintain the joint line by cutting the tibia first.
2 Perform minimal medial releases while leaving lateral laxity.
3 Adjust the resection thickness of the distal and posterior aspects of the medial femoral condyle after assessing the medial extension and flexion gaps in order to ensure that they will be equal.
References
1. Okamoto S, Okazaki K, Mitsuyasu H, Matsuda S, Iwamoto Y. Lateral Soft Tissue Laxity Increases but Medial Laxity Does Not Contract with Varus Deformity in Total Knee Arthroplasty. Clin Orthop Relat Res. 2013;471(4):1334-42. 2. Nakamura S, Kuriyama S, Nishitani K, Ito H, Murata K, Matsuda S. Correlation Between Intraoperative Anterior Stability and Flexion Gap in Total Knee Arthroplasty. J Arthroplasty. 2018;33(8):2480-4. 3. Tsubosaka M, Muratsu H, Takayama K, Maruo A, Miya H, Kuroda R, Matsumoto T. Effect of intraoperative soft tissue balance on postoperative recovery of ambulatory and balancing function in posterior-stabilized total knee arthroplasty. J Orthop Sci. 2019;24(3):507-13. 4. Kamenaga T, Muratsu H, Kanda Y, Miya H, Kuroda R, Matsumoto T. The Influence of Postoperative Knee Stability on Patient Satisfaction in Cruciate-Retaining Total Knee Arthroplasty. J Arthroplasty. 2018;33(8):2475-9. 5. Minoda Y, Mizokawa S, Ohta Y, Ikebuchi M, Itokazu M, Yamamura K, Nakamura S, Nakamura H. Posterior reference guides do not always maintain the size of posterior femoral condyles in TKA. Knee Surg Sports Traumatol Arthrosc. 2016;24(8):2489-95.
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ISAKOS NEWSLETTER 2019: VOLUME II 31