Radiocarpal osteoarthritis associated with bilateral bipartite carpal scaphoid bones: a case report

Bipartite carpal scaphoid is a rare congenital anomaly. The authors report on a 56-year-old man who presented with bilateral wrist pain without a history of trauma. X-ray films demonstrated bilateral symmetric bipartition of the scaphoid into a large distal ossicle and a smaller proximal ossicle. There was degenerative change in the articulation between the distal ossicle and the radial styloid. The joint space between the proximal ossicle and the scaphoid fossa was preserved. The absence of periscaphoid degenerative change has been suggested as a criterion for the diagnosis of congenital bipartite scaphoid. This patient fulfilled all other criteria for the diagnosis and the authors suggest that degenerative change developed due to abnormally high contact force between the distal ossicle and the radial styloid. An identical pattern of degenerative change has been observed in long-standing nonunion of the scaphoid, likely due to a similar mechanism. Radiocarpal osteoarthritis can develop in patients with congenital bipartition of the scaphoid and is similar to that observed in long-standing nonunion of the scaphoid.     

Treatment of dynamic scaphoid instability

BACKGROUND: Chronic wrist pain attributable to scaphoid instability without fixed deformity (dynamic instability) presents a treatment dilemma. The diagnosis usually is delayed, missing the opportunity for direct repair. The intercarpal fusion, tenodesis, and capsulodesis procedures create a fixed deformity. This report presents an outcome study of a new treatment for dynamic scaphoid instability that spanned more than 5 years. METHODS: Arthroscopic evaluation was used to confirm the diagnosis for 105 wrists of 102 patients who had experienced wrist pain for an average of 24.4 months. The treatment for these patients involved transferring two thirds of the extensor carpi radialis longus through the distal pole of the reduced scaphoid volarly to the intact flexor carpi radialis. The postoperative follow-up period averaged 63 months. RESULTS: The average grip strength increased by 65%. The average active wrist extension-flexion increased by 9%, with an average radial deviation loss of 6 degrees. The overall results, as measured by the modified Green and O'Brien clinical wrist scale, were as follows: excellent (49%), good (24%), and fair (26%). Good to excellent results were reported by 85% of the patients. Pain relief was reported by 94% of the patients, and 93% of the patients would recommend the procedure to others. CONCLUSIONS: Scaphoid instability without fixed deformity is a complex problem. Conventional treatments have drawbacks. The new technique produced positive results that are quite promising for the management of dynamic scaphoid instability.     

Occipitoatlantal instability associated with articular tropism

The authors report the case of a patient with rotatory posterior subluxation of the occiput on the atlas associated with tropism of the O-C1 articulations. Lateral flexion-extension plain films demonstrated 5 mm of posterior translation of the occiput on the atlas. Tomographs revealed tropism of the O-C1 articulations, and CT scans on extension demonstrated posterior rotatory subluxation of the occiput on the atlas. The patient had no osseous abnormality caudally below the atlantoaxial joint, and underwent posterior occipitoatlantal fusion by wiring. At the 4-year follow-up, the grafted bone had been incorporated, and the patient was completely free from preoperative symptoms. In the present patient, occipitoatlantal instability is presumed to have derived from articular tropism. Received: 8 March 1997 Revised: 5 June 1997 Accepted: 24 June 1997     

Arthroscopic and open management of dynamic scaphoid instability

This article focuses on the pathophysiology and treatment of dynamic scaphoid instability. Cadaver studies suggest that dynamic instability results from isolated injury to the scapholunate interosseous ligament without damage to the dorsal intercarpal and dorsal radial lunotriquetral ligaments. The diagnosis may be made by dynamic fluoroscopic examination, including stress and load views. The role of arthroscopy is twofold: (1) it enables the surgeon to distinguish between a complete, grossly unstable scapholunate interosseous space that requires open treatment and (2) it permits direct visualization of the reduction and percutaneous pinning of the articulation in an effort to stabilize the joint. Operative indications, open and arthroscopic techniques, and results are discussed.     

Spontaneous correction of dorsal intercalated segment instability deformity with scaphoid malunion in the skeletally immature

This is a report on two children with dorsal intercalated segment instability deformity of the carpus associated with malunited fracture of the scaphoid. The patients were observed over 4 years, and spontaneous improvement was noted in association with growth.     

Radiographic clues for determining carpal instability and treatment protocol for scaphoid fractures

The magnitude of carpal instability following scaphoid fracture is closely related to the fracture location. Middle-third fractures of the scaphoid are classified into B1 (distal oblique fractures) and B2 (complete waist fractures). Deciding preoperatively whether a fracture is B1 or B2 is clinically important, because several studies have revealed that B1 is more stable than B2. Dorsal intercalated segment instability deformity often develops in B2, creating a large, wedge-shaped bone defect, while minimal humpback deformity develops in B1, and the bone defect is much smaller, even after long-standing nonunions. However, determination of the fracture types using X-rays may be less accurate than using three dimensional computed tomography. This article suggests two radiographic clues for estimation of post-fracture carpal instability along with a treatment protocol for each fracture type.     

The role of carpal instability in scaphoid nonunion: casual or causal?

We studied twenty consecutive scaphoid nonunions in twenty patients between the ages of eighteen and thirty-eight years. There were nineteen males and one female. The mean age was 25.2 years. Factors evaluated were fracture displacement, delay in treatment, and carpal instability. Fracture displacement and carpal instability were documented in patients by abnormal x-rays showing fragment displacement, abnormal scapholunate and radiolunate angles, etc., or by fluoroscopically controlled arthrography. We concluded that intercarpal ligamentous instability is consistently present and, therefore, the critical factor in wrists with ununited scaphoid fractures. Thirteen patients have been treated surgically; ligamentous disruption was confirmed at surgical exploration. In twelve patients, treatment of the nonunion included intercarpal ligamentous reconstruction. A satisfactory outcome was achieved in all twelve of these patients. One patient's treatment did not include ligament reconstruction. Although the scaphoid fracture united after a Russe bone graft, he remains symptomatic with persistent intercarpal instability. The remaining seven patients are being evaluated or awaiting surgery. Since ligamentous injury is so common in nonunion, we believe it is causal and that surgical care of nonunion involves ligamentous repair or other stabilization procedure. Prevention of nonunion involves early attention to the therapy of carpal instability when associated with scaphoid fracture.     

楔形植骨治疗伴近排腕骨背伸不稳定的舟骨骨折

目的　探讨应用楔形植骨法治疗伴近排腕骨背伸不稳定 (dorsalintercalatedsegmentinstability ,DISI)舟骨骨折的临床疗效。方法　回顾性地研究了 2 6例患者 ,术后平均随访 10 .2个月 ,重点分析了术后疗效。结果　骨折愈合率为 10 0 % ,愈合时间为 [(6.1± 3 .4)个月 , x±s ,下同 ]。术后患腕关节活动范围较术前无明显差别 ,但握力、腕关节疼痛和DISI均有明显改善 ;未见内固定物松动、断裂。结论　楔形植骨不仅能帮助舟骨愈合 ,而且可较好地矫正舟骨本身的掌屈畸形和DISI ,保持舟月骨相互关系的动态平衡 ,方法简单 ,疗效可靠     

An experimental study of instability during supination and pronation of the fractured scaphoid

Rotatory instability of scaphoid fractures was studied by a method not used previously. On two fresh specimens the scaphoid bone was fractured by osteotomy, and the fracture was fixed by a Hoffmann apparatus extending from the distal radius to the 1st, 2nd and 3rd metacarpals. This permits free rotation in the forearm. The scaphoid fragments were marked by Kirschner wires. No movement occurred between the fragments when supination/pronation was kept within the normal range of movement.     

与国人舟骨形态学相关的舟骨螺钉内固定应用

目的 探讨与国人舟骨形态学相关的舟骨螺钉内固定应用.方法 测量27例成人舟骨标本的舟骨长轴长度(沿舟骨长轴线从近极到远极关节面的距离)、舟骨腰部宽度、远极宽度和近极宽度(垂直于舟骨长轴的方向,分别测量舟骨腰部最窄部位的宽度、距离远极关节面2 mm处的远极宽度和距离近极顶端2 mm处的近极宽度),男17例,女10例.比较男性和女性标本的测量数据,并分别同国内可供选择的舟骨内固定螺钉的各项指标进行比较分析.结果 舟骨长轴长度:男性标本(29.3±1.3)mm,女性标本(25.4±1.1)mm,两者比较差异有统计学意义.舟骨腰部宽度、近极宽度和远极宽度男性标本分别为(10.3±0.8)mm、(4.5±0.6)mm和(6.0±0.5)mm,女性标本分别为(9.0±0.8)mm、(4.0±0.4)mm和(5.6±0.4)mm,男性标本的测量值均显著大于女性标本.所有舟骨标本的平均近极宽度均小于远极宽度.国内部分可供选择的舟骨螺钉产品(3.0空心螺钉垫圈系统和部分Acutrak标准型螺钉)的尾端直径大于舟骨近极平均宽度.结论 根据舟骨形态学相关测量结果,治疗舟骨骨折螺钉的适宜平均长度男、女性分别为25 mm和21 mm.因国人舟骨近极宽度相对较窄小,选择背侧入路从近极置入螺钉时,应选择尾端直径适宜的螺钉产品,以减少并发症的发生率.     

Experimental corrective scaphoid osteotomy for scaphoid malunion with abnormal wrist mechanics

Two cases of painful posttraumatic scaphoid malunion (hump-back deformity) associated with dorsal intercalated segmental instability deformity and limitation of wrist motion are presented. Carpal alignment and wrist motion improved after an experimental opening wedge scaphoid osteotomy with iliac bone graft and Herbert screw fixation. The scaphoid deformities (angulation and shortening) were effectively corrected.     

The effects of focal articular defects on cartilage contact mechanics

Focal damage to articular cartilage is common in arthroscopy patients, and may contribute to progressive tissue degeneration by altering the local mechanical environment. The effects of a focal defect, which may be oriented at various orientations relative to the subchondral bone, on the dynamics of cartilage contact and deformation are unclear. The objective of this study was to elucidate the effect of experimental full thickness focal defects, oriented at 80° or 100° relative to the subchondral bone, on intratissue strain and surface sliding of opposing cartilage surfaces during compression and stress relaxation. Pairs of intact bovine osteochondral blocks were compressed uniaxially by 20%, and allowed to stress relax. Tissue deformation was recorded by video microscopy. A full‐thickness defect (with either 80° or 100° edges) was created in one block from each pair. Blocks were allowed to reswell and retested. Defect edges were then recut with the opposite orientation, allowed to reswell, and retested again. Stained nuclei were tracked by digital image correlation and used to quantify cartilage strains and surface sliding. The results indicated that loading of intact samples caused axial strain magnitudes that decreased with depth and relatively little sliding. With loading of samples containing defects, strain magnitudes were elevated in cartilage adjacent to, and opposing, defects. For samples with edge orientations of 100°, sliding magnitudes were increased over surfaces adjacent to defects. These local mechanical changes due to full‐thickness articular cartilage defects may contribute to altered chondrocyte metabolism, tissue damage, or accelerated wear. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 584–592, 2009     

New methods for assessing cartilage contact stress after articular fracture

Progress in reducing the incidence and severity of posttraumatic arthritis depends in part on avoiding deleterious stress levels at residual local incongruities. Systematic efforts to elucidate factors adversely influencing cartilage's mechanical environment in turn depend on the availability of suitable modalities to assess intraarticular contact stresses. This has been and remains a challenging biomechanical problem. Technologic approaches used in the past have included mathematical analyses and indwelling physical sensors, each with advantages and limitations. Two emerging, mutually complementary capabilities show promise of dramatically altering the state of the art in this important field. The first of these methodologies, voxel-based contact finite element analysis, provides accurate computational estimates of cartilage stress on a patient-specific basis, and does so while accommodating arbitrarily idiosyncratic patterns of local articular incongruity. The second methodology, instrumentational, involves transient pressure distribution recordings using specially designed piezoresistive array sensors. Operational considerations for both of these new assessment technologies are described, and promising directions for future development are outlined.