Department of Orthopaedic Surgery, University of California Los Angeles, Los Angeles, CA; and.
Musculoskeletal Education and Research Center, A Division of Globus Medical, Inc., Audubon, PA .
J Orthop Trauma. 2024 Aug 1;38(8):435-440. doi: 10.1097/BOT.0000000000002839.
To assess the biomechanical differences between linked and unlinked constructs in young and osteoporotic cadavers in addition to osteoporotic sawbones.
Intraarticular distal femur fractures with comminuted metaphyseal regions were created in three young matched pair cadavers, three osteoporotic matched pair cadavers, and six osteoporotic sawbones. Precontoured distal femur locking plates were placed in addition to a standardized retrograde nail, with unitized constructs having one 4.5 mm locking screw placed distally through the nail. Nonunitized constructs had seven 4.5 mm locking screws placed through the plate around the nail, with one 5 mm distal interlock placed through the nail alone. Cadaveric specimens were subjected to axial fatigue loads between 150 and 1500 N (R Ratio = 10) with 1 Hx frequency for 10,000 cycles. Sawbones were axially loaded at 50% of the ultimate load for fatigue testing to achieve runout, with testing performed with 30 and 300 N (R Ratio = 10) loads with 1 Hz frequency for 10,000 cycles.
In young cadavers, there was no difference in the mean cyclic displacement of the unitized constructs (1.51 ± 0.62mm) compared to the non-unitized constructs (1.34 ± 0.47mm) (Figure 4A), (p = 0.722). In osteoporotic cadavers, there was no difference in the mean cyclic displacement of the unitized constructs (2.46 ± 0.47mm) compared to the non-unitized constructs (2.91 ± 1.49mm) (p =0.639). There was statistically no significant difference in cyclic displacement between the unitized and non-unitized groups in osteoporotic sawbones(p = 0.181).
Linked constructs did not demonstrate increased axial stiffness or decreased cyclical displacement in comparison to unlinked constructs in young cadaveric specimens, osteoporotic cadaveric specimens, or osteoporotic sawbones.
评估在年轻和骨质疏松尸体标本以及骨质疏松性骨锯标本中，连接和非连接结构之间的生物力学差异。
在三个年轻配对尸体标本、三个骨质疏松配对尸体标本和六个骨质疏松性骨锯中，创建了关节内股骨远端骨折伴粉碎性干骺端区域。除了标准化逆行钉外，还放置了预成型股骨远端锁定板，单元化结构在钉上有一个 4.5mm 的锁定螺钉置于远端。非单元化结构在钉周围的钢板上有七个 4.5mm 的锁定螺钉，单独用一个 5mm 的远端交锁螺钉穿过钉。尸体标本在 150 至 1500N 的轴向疲劳载荷（R 比=10）下以 1Hz 频率进行 10000 次循环。骨锯在达到失效前以 50%的极限载荷进行轴向加载进行疲劳试验，测试在 30N 和 300N（R 比=10）载荷下，以 1Hz 频率进行 10000 次循环。
在年轻尸体标本中，单元化结构（1.51±0.62mm）的平均循环位移与非单元化结构（1.34±0.47mm）无差异（图 4A）（p=0.722）。在骨质疏松尸体标本中，单元化结构（2.46±0.47mm）的平均循环位移与非单元化结构（2.91±1.49mm）无差异（p=0.639）。在骨质疏松性骨锯中，单元化和非单元化组之间的循环位移无统计学差异（p=0.181）。
与非连接结构相比，连接结构在年轻尸体标本、骨质疏松尸体标本或骨质疏松性骨锯中并未表现出轴向刚度增加或循环位移减少。
