Managing scaphoid fractures. How we do it?

The scaphoid is the common carpal bone to be fractured. Proper clinical and radiological evaluation is required to establish it's diagnosis. The management of acute fractures includes conservative treatment with cast in minimally displaced to open reduction and internal fixation in case of displaced ones. The established nonunion requires open reduction, bone grafting and internal fixation.     

Missed isolated volar dislocation of the scaphoid

A patient presented with volar dislocation of the scaphoid, the diagnosis of which had been missed for two weeks. He was treated with open reduction through a combined volar and dorsal approach with decompression of the median nerve, internal fixation, and a cast for eight weeks. One year postoperatively the functional result was good. A radiograph showed no sign of avascular necrosis.     

腕关节镜下植骨经皮内固定治疗舟骨骨折不愈合

目的探讨腕关节镜辅助微创植骨内固定治疗舟骨骨折不愈合手术方法和疗效。 方法2015年10月至2018年10月,采用腕关节镜辅助微创方法治疗外固定未愈合的不稳定型舟骨骨折9例,9例患者均为舟骨骨折不愈合,无合并舟月分离及舟骨近极塌陷。所有患者根据术前影像学检查评估舟骨骨折移位情况,骨折端硬化和骨质吸收缺损情况。术中从腕中关节入路刨除硬化骨后复位植骨内固定。收集患者术前及术后Mayo评分和疼痛视觉模拟评分(VAS评分),两组间数据比较采用配对t检验。 结果9例患者均获得随访,随访时间平均(11±4)个月。所有患者末次随访之时均获得骨性愈合,Mayo腕关节评分(89.4±5.8)分,与术前(52.2±6.7)分相比(t＝19.8,P<0.001),优8例,良1例。VAS评分由术前(5.2±0.7)分降至(1.6±0.7)分(t＝15.6,P<0.001)。 结论腕关节镜辅助微创治疗不稳定型舟骨骨折不愈合是一种有效的治疗选择,采用腕关节镜技术去除硬化骨,取髂骨碎屑植骨内固定能取得较为理想的临床效果。     

Establishing a central zone in scaphoid surgery: a computational approach

Purpose

Scaphoid fractures are commonly fixed with headless cannulated screws positioned centrally in the scaphoid. Judgement of central placement of the screw may be difficult. We generated a central zone using computer analysis of 3D reconstructions of computed tomography (CT) images. As long as the screw axis is completely contained within this central zone, the screw would be considered as centrally placed.

Methods

Thirty cases of 3D CT reconstructions of normal scaphoids in a computerised operation planning and simulation system (Vxwork software) were obtained. The central zone was established after some distance shrinkage of the original scaphoid surface reconstruction model using the function “erode” in the software. The shape of the central zone was evaluated, and the width of the central zone in the proximal pole, waist portion and distal pole was measured. We also established the long axis of the scaphoid to see whether it stays in the central zone.

Results

All central zones could be divided into distal, waist and proximal portions according to the corresponding irregular shape of the scaphoid. As the geometry of the central zone was so irregular and its width very narrow, it was possible to completely contain the screw axis either in the proximal portion alone, waist alone or distal central zone alone.

Conclusions

Establishing the central zone of scaphoid 3D CT images provided a baseline for discussion of central placement of a scaphoid screw. The geometry of the scaphoid central zone determined that the screw could hardly be inserted through entire scaphoid central area during surgery.     

Salvage of a post-traumatic arthritic wrist using the scaphoid as an osteochondral graft

The authors describe a case of post-traumatic wrist arthritis with an osteochondral defect in the scaphoid fossa of the radius. The patient was treated with proximal row carpectomy, radial styloidectomy and reconstruction of the defect using the proximal half of the scaphoid as an autologous osteochondral graft. Pain relief was achieved while wrist motion and strength were improved. The carpal bones are a source of osteochondral grafts and can be used to expand the indications of motion-preserving wrist salvage procedures.     

Three-dimensional comparison of alternative screw positions versus actual fixation of scaphoid fractures

PurposeThe recommended technique for the fixation of a scaphoid waist fracture involves a headless compression screw placed in the proximal fragment center. This is usually accomplished by placing a longitudinal axis screw as visualized by fluoroscopy. The screw length has been shown to have a biomechanical advantage. An alternative to these options, which has been debated in the literature, is a screw placed perpendicular to the fracture plane and in its center. The perpendicular screw may have a biomechanical advantage despite the fact that it may be shorter. This study examined the differences in location and length in actual patients between a screw in the center of the proximal fragment with a longitudinal axis screw, and the actual fixating screw. These were then compared to a perpendicular axis screw.MethodsPre- and post-operative CT scans of 10 patients with scaphoid waist fractures were evaluated using a 3D computer model. Comparisons were made between the length, location and angle of actual and virtual screw alternatives; namely, a screw along the central third of the proximal fragment (central screw axis) where the scaphoid longitudinal axis was calculated mathematically (longitudinal screw axis) and a screw placed at 90 ° to the fracture plane and in its center (perpendicular screw axis).ResultsThe longitudinal axis screw was found to be significantly longer than the other axes (28.3 mm). There was a significant difference between the perpendicular axis screw and the location and angle of the other screw axis, but it was only shorter than the longitudinal screw (23.6 mm versus 25.5 mm for the actual screw; ns.).ConclusionsA computed longitudinal axis screw is longer than a central or actual screw placed longitudinally by visual inspection by the surgeon. Although it needs to be placed using computer assisted (CAS) techniques, it may have the biomechanical advantages of a longer screw in a similar trajectory. The perpendicular screw was found to be significantly different in position and angle but not shorter than the actually placed screw. It has biomechanical advantages and does not require visualization with CAS methods, making it the more attractive alternative.     

Palmar-divergent dislocation of the scaphoid and the lunate

We describe a patient with palmar-divergent dislocation of the scaphoid and lunate. After successful closed reduction, the scapholunate and lunotriquetral ligaments were sutured through the dorsal approach, and the anterior capsule was sutured through the palmar approach. The scapholunate and lunotriquetral joints were fixed with Kirschner wires for 7 weeks. At the 1-year follow-up, magnetic resonance imaging showed no evidence of avascular necrosis of the scaphoid or lunate, and radiographs showed no evidence of the dorsal and volar intercalated segment instability patterns associated with carpal instability. However, flexion of the scaphoid and a break in Gilula’s line remained. To our knowledge, this is the first report showing treatment of palmar-divergent dislocation of the scaphoid and lunate by suturing the carpal interosseous ligaments.