股骨远皮质锁定系统治疗股骨远端骨折的前瞻性观察研究.doc

【2012AAOS专题报道】标题：股骨远皮质锁定系统治疗股骨远端骨折的前瞻性观察研究摘要引言最近的研究显示，采用传统的锁定钢板治疗股骨髁上骨折不愈合率约为19%-22%。一般认为， 这一内固定结构具有较高的刚度，而在骨折不愈合中起了重要的作用。有研究发现，在羊的胫骨骨折模型中，远皮质锁定系统的刚度下降了80%，但可以增加56%的愈合强度。我们这一前瞻性研究首次对股骨远皮质锁定系统的临床特性进行了探讨。方法在该前瞻性观察研究中，连续14例股骨远端骨折（AO分型33 A型、33 C型） 患者采用经皮桥接内固定的方法进行手术。使用的材料为关节周围钛制锁定接骨板，骨干部分用四枚远皮质锁定螺钉固定，干骺端用标准的锁定螺钉固定。术中没有植骨也没有应用骨形态发生蛋白。在手术后第6周（14例），12周（10例），24周（5例） X线片上和第12周的CT片上通过计算皮质骨痂桥接的数量来评估骨折愈合。应用经过验证了的方法（误差小于5%）客观地测量了内侧、前侧和后侧骨皮质的骨膜骨痂的多少。骨痂测量的数据与66例采用标准锁定钢板治疗股骨远端骨折的数据进行历史比较。结果患者平均年龄为74岁(范围55- 89岁)。14例病人中有1例是吸烟者，4例患有糖尿病。有1例开放性骨折和8例人工关节假体周围骨折。在第12周，71%的骨折在内侧、后侧和前侧骨皮质中出现了骨痂组织。第24周的时候，96%的骨折其内侧，后侧和前侧皮质中出现了骨痂组织。也就是说，在所有的患者中至少有两处骨皮质被骨痂桥接（图1）。骨膜骨痂大小平均为113mm2（第6周），154mm2（12周）和157mm2（24周），采用标准锁定钢板的数据62mm2 （第6周，P=0.01），93mm2（12周，p=0.09）和114mm2（24周，P=0.4）。除了骨痂增加以外，股骨远皮质锁定系统产生了分布非常对称的骨痂（第6周：内侧骨痂31%，前侧骨痂42%，后侧骨痂27%）。本组病例中没有发生内固定断裂，骨干部也没有出现内固定松动。一例假体周围骨折的病例由于干骺端固定不足而导致内翻，但不需要翻修。讨论和结论早期随访结果表明，相对于传统的锁定钢板，股骨远皮质锁定系统可以促进骨痂形成。本组病例中，股骨远皮质锁定系统没有出现内固定断裂或固定失效等并发症。Far Cortical Locking of Distal Femur Fractures: A Prospective Observational StudyINTRODUCTIONRecent studies show a nonunion rate of 19-22% for supracondylar femur fractures treated with conventional locked plates. The relatively high stiffness of these constructs is thought to play a role in the nonunion rate. FCL constructs have been shown to decrease construct stiffness by 80% and to yield 156% stronger healing in an ovine tibia fracture model. This prospective study documents for the first time the clinical performance of FCL constructs.METHODSIn a prospective observational study, distal femur fractures (AO/OTA 33A and 33C) in 14 consecutive patients were stabilized in a percutaneous bridge plating approach using a titanium periarticular locking plate with four FCL screws in the diaphysis. Standard locking screws were used for metaphyseal fixation. No bone grafts or bone morphogenic proteins were administered to enhance fracture healing. Healing was assessed by the number of bridged cortices on radiographs at week 6 (n=14), week 12 (n=10), and week 24 (n=5) and by CT at 12 weeks post surgery. Periosteal callus size was objectively measured at the medial, anterior and posterior cortices using a validated computational algorithm with an error of less than 5%. Callus measurements were compared to a published series of historic control data from 66 distal femur fractures treated with standard locked plating constructs.RESULTSAverage patient age was 74 years (range 55-89). Of the 14 patients, one was a smoker and four had diabetes. There was one open fracture and eight periprosthetic fractures. At week 12, bridging callus was present in 71% of medial, posterior, and anterior cortices. At week 24, bridging callus was present in 96% of medial, posterior and anterior cortices (Figure 1), whereby at least two of the three cortices were bridged in all patients. The average periosteal callus size was 113 mm2 (week 6), 154 mm2 (week 12), and 157 mm2 (week 24) compared to historic control data of 62 mm2 (week 6, p=0.01), 93 mm2 (week 12, p=0.09) and 114 mm2 (week 24, p=0.4) for standard locked plating constructs. In addition to increased callus size, FCL fixation yielded considerably symmetric callus distribution (week 6: 31% medial, 27% anterior, 42% posterior callus). There was no incidence of hardware failure. There was no failure of FCL fixation in the diaphysis. One periprosthetic fracture migrated into varus due to deficient metaphyseal fixation but did not require revision.DISCUSSION AND CONCLUSIONResults suggest that FCL constructs can improve callus formation relative to hi