Matziolis Georg, Brodt Steffen, Windisch Christoph, Roehner Eric
Orthopedic Department, Friedrich-Schiller University, Campus Eisenberg, Jena, Germany.
Orthopedic Department, University Hospital Jena, Campus Eisenberg, Klosterlausnitzer Straße 81, 07607, Eisenberg, Germany.
Arch Orthop Trauma Surg. 2017 May;137(5):713-717. doi: 10.1007/s00402-017-2671-5. Epub 2017 Mar 16.
There is no algorithm for the management of joint stability in midflexion up to now. Change in the joint line (JL) is considered to be the primary cause, although it only determines the extension gap. The purpose of this study was to determine the influence of the posterior condylar offsets (PCO), which defines the flexion gap, on midflexion instability.
Forty-two knee joints (38 patients) were included in this study, patients undergoing navigated total knee arthroplasty due to primary osteoarthritis of the knee. Changes in the JL and the PCO were determined from the navigation data. A gap tensioning device was used to determine the width of the joint gap at -5°, 0°, 30° and 60° intraoperatively.
Within a range between 5 mm proximalization and 2 mm distalization, the JL had no influence on stability in midflexion. In contrast to this, both an increase and a decrease in PCO led to midflexion instability (R = 0.361, p = 0.019). In 16 cases (38%), the PCO was changed by more than 2 mm. This led to a midflexion instability of more than 2 mm in seven of these cases (44%).
Whereas the joint line can be displaced by up to 5 mm without measurable changes in joint stability, reconstruction of the posterior offset within a tight range of 2 mm is necessary to avoid midflexion instability.
目前尚无针对膝关节中屈曲位关节稳定性管理的算法。关节线（JL）的变化被认为是主要原因，尽管它仅决定伸直间隙。本研究的目的是确定定义屈曲间隙的后髁偏移（PCO）对中屈曲位不稳定性的影响。
本研究纳入了42个膝关节（38例患者），这些患者因膝关节原发性骨关节炎接受导航下全膝关节置换术。通过导航数据确定JL和PCO的变化。术中使用间隙张紧装置确定在-5°、0°、30°和60°时关节间隙的宽度。
在近端移位5mm至远端移位2mm的范围内，JL对中屈曲位的稳定性没有影响。与此相反，PCO的增加和减少均导致中屈曲位不稳定（R = 0.361，p = 0.019）。在16例（38%）病例中，PCO的变化超过2mm。其中7例（44%）导致中屈曲位不稳定超过2mm。
关节线可移位达5mm而关节稳定性无明显变化，然而，在2mm的狭窄范围内重建后偏移对于避免中屈曲位不稳定是必要的。
