Apport de l’imagerie dans le diagnostic de la vascularisation osseuse à la main et au poignet

The viability of the bone is compromised in two main situations at the wrist: Kienböck's disease and scaphoid nonunion with avascular necrosis. Plain radiography and CT allow an accurate anatomical approach of morphological changes associated with avascular necrosis of the lunate and the scaphoid fracture with complications. CT is readily available to detect nondisplaced fractures. However, early forms of necrosis can be misdiagnosed and evaluation of bone vitality is impossible. MRI is the best imaging modality to detect avascular necrosis and the intravenous injection of gadolinium improves the specificity of diagnosis of necrosis. The lack of enhancement of the proximal fragment of the scaphoid leads the surgeon to use a vascular graft in the treatment of nonunion. The technique has its limitations. The bone necrosis is histologically complex and contrast enhancement does not mean necessarily viability. However, MRI is still the most powerful imaging modality in the assessment of the bone marrow.     

Microsurgical reconstruction of the scaphoid and lunate bones with small, free vascularized iliac crest bone grafts

The primary surgical goal in repairing a scaphoid nonunion, particularly one associated with avascular fragments, or reconstructing the lunate is to prevent progressive carpal collapse. In patients with persistent nonunion of the scaphoid and progressive aseptic necrosis of the lunate bone, reconstruction can be managed with a small microvascular iliac crest bone transfer. This retrospective study reports on the anatomical fundamentals, the operative procedure (particularly the harvesting of the bone flap and microsurgery), the assessment of the viability of the bone graft and the postoperative results in 80 out of a total of 210 patients on whom the surgery had been performed. From 1985 until 1998, 210 carpal bone reconstructions (134 scaphoid bones and 76 lunate bones) were performed using small, free vascularized iliac crest bone grafts. Of these, 80 patients were preoperatively evaluated and postoperatively followed up clinically and by means of conventional radiography and magnetic resonance imaging (MRI). The total rate of viability and bony union was 91.2%. This means a bone flap loss-rate and, consequently, a progressive arthrosis/necrosis/persistent nonunion of 8.8%. The patients who had vital reconstructed carpal bones did not report pain, but motion and grip strength were decreased as compared with the uninvolved side. This procedure offers stability and vascularity to treat avascular scaphoid nonunion and has proved beneficial in achieving union in avascular scaphoid pseudoarthrosis and lunate necrosis. It can be considered to be the definitive alternative technique. The high rate of union and the absence of progressive carpal arthrosis are the best evidence for the vascularity of the bone graft.     

Percutaneous Screw Fixation of Scaphoid Waist Fracture Non-Union Without Bone Grafting

The aim of the study was to evaluate results of volar percutaneous headless compression screw fixation without bone grafting in 21 patients with scaphoid waist nonunion fractures. The inclusion criteria in this series were scaphoid waist fracture nonunion with intact cartilaginous envelope, minimal fracture line at nonunion interface, no cyst or sclerosis, no avascular necrosis and normal scapholunate angle without humpback deformity. There were 17 male and 4 female patients with an average age of 23 years (range 16–45 years). All patients had radiographic examinations that included Posteroanterior, lateral, oblique and scaphoid views. Preoperative MRI to assess the cartilaginous shill and vascularity of scaphoid was done. CT scans were performed postoperatively to confirm scaphoid fracture healing. The average clinical follow-up was at 25 months (range 18–35) postoperatively. All fractures united successfully with no additional procedures. The average DASH score (disabilities of the arm, shoulder, and hand) at final follow-up was 8 (range 0–16). Percutaneous fixation for selected scaphoid nonunion can avoid the morbidity of an open approach and bone grafting.     

Dorsal capsular-based vascularized distal radius graft for proximal pole scaphoid nonunion with avascular necrosis

BackgroundScaphoid nonunion involving the proximal pole with the presence of avascular necrosis is difficult to reconstruct. We aimed to determine the efficacy of surgical treatment of proximal pole scaphoid nonunion with avascular necrosis using a dorsal capsular-based vascularized distal radius graft.MethodsBetween 2000 and 2018, 64 patients with established proximal pole scaphoid nonunion with avascular necrosis were treated using a dorsal capsular-based vascularized distal radius graft. This graft was harvested from the dorsal aspect of the distal radius with its dorsal wrist capsule attachment. Fixation of the scaphoid nonunion was performed with a small cannulated screw, followed by insertion of the vascularized graft into the dorsal trough at the scaphoid nonunion site. In the last 47 patients of this series, a micro suture anchor was placed into the scaphoid to augment graft fixation.ResultsUnion rate was 86% (55 of 64 scaphoid nonunions with avascular necrosis) at a mean time of 12 weeks. Persistent non-union was noted in eight patients and fibrous union in one patient. No patients developed donor site morbidity. No graft dislodgment was noted. There was significant improvement of the wrist functional outcomes at the final follow up.ConclusionsThe dorsal capsular-based vascularized distal radius graft is a safe and effective treatment in patients with scaphoid nonunion with avascular necrosis of the proximal pole. This pedicle vascularized bone graft is derived from a location that can easily reach the proximal third of the scaphoid avoiding microsurgical dissection or anastomosis.     

Avascular necrosis of the scaphoid in children treated by splint immobilisation: a report of two cases

Avascular necrosis of the scaphoid following a fracture in children is rare and there is no established treatment protocol in the literature. We present two boys with nonunion and avascular necrosis of the scaphoid treated by simple immobilisation. Both cases healed with painless wrists and full movements. Our cases confirm that an ununited scaphoid fracture in children may heal with conservative treatment, even when an MRI scan suggests avascular necrosis. Unlike in adults, operative treatment need only be considered in children when conservative treatment fails.     

Free medial femoral condyle bone grafting for scaphoid nonunions with humpback deformity and proximal pole avascular necrosis

Treatment of scaphoid nonunions remains a challenging problem, especially in the setting of proximal pole avascular necrosis or humpback deformity. Conventional bone grafting techniques have demonstrated unpredictable results in the setting of collapse deformities, whereas pedicled dorsal distal radius vascularized bone grafts have recently been reported to have nearly a 50% failure rate when used in scaphoid nonunions with proximal pole nonunion. Free vascularized medial femoral condyle bone grafting is one option for the treatment of scaphoid nonunions with proximal pole avascular necrosis associated with a humpback deformity. The indications, contraindications, and technique of free vascularized medial femoral condyle bone grafting are presented for the treatment of scaphoid nonunions associated with proximal pole avascular necrosis and humpback deformities.     

Scaphoid nonunions. Pitfalls and pearls.

Our ability to treat scaphoid nonunions has improved dramatically. The degree of collapse and bone loss can be accurately assessed in waist fractures using sagittal images on CT scans. These nonunions require reduction and bone grafting to re-establish the normal geometry of the scaphoid. Magnetic resonance imaging helps evaluate whether or not avascular necrosis is present in the proximal pole. Because of the poor prognosis of conventional bone grafts, a vascularized bone graft is recommended as the primary treatment when AVN is present. The volar collapse of the humpback deformity is best corrected with a volar approach and the proximal pole nonunion is best approached using a dorsal approach. Nearly all proximal pole nonunions require a vascularized bone graft and all acute proximal pole fractures require open reduction and internal fixation. Using specially designed cannulated screws, the nonunions can be stabilized accurately to decrease the time to resolution of the nonunion and minimize the amount of time in a cast. Stable fixation requires that the screw fixation target the central portion of the scaphoid regardless of the type of screw design used. Using these techniques, the hand surgeon should be able to provide a reasonable prognosis for patients presenting with a scaphoid nonunion, and the treatment should result in functional range of motion, grip strength, and relief of pain.     

Magnetic resonance imaging to assess vascularity of scaphoid nonunions

The unreliability of current methods of assessing of bone vascularity is well documented, precluding any prospective analysis of its influence on bone healing. In hopes of accurately predicting scaphoid vascularity, magnetic resonance imaging was used prospectively in patients with radiographic evidence of nonunion. Magnetic resonance imaging scans were compared to plain radiographs, tomograms, and the operative impressions of the surgeon. The diagnostic accuracy of each test was determined by a pathologist's interpretation of histological sections. Ten of thirteen surgical specimens were available for analysis. The magnetic resonance imaging scan accurately predicted scaphoid viability in all ten cases (three viable, seven avascular). This compared with diagnostic errors in six of ten plain radiographs, one of seven tomographs, and two of ten surgical assessments. Magnetic resonance imaging can accurately predict the vascularity of the ununited scaphoid. With further follow-up of these patients, the capability of the avascular scaphoid to heal will become evident. Definitive preoperative determination of the healing potential of scaphoid nonunions may then be possible, thereby aiding the surgeon's choice of the appropriate surgical procedure.     

Correlation of magnetic resonance imaging and intraoperative punctate bleeding to assess the vascularity of scaphoid nonunion

Thirty-two patients with radiographic evidence of scaphoid nonunion were preoperatively evaluated by magnetic resonance imaging (MRI), then observed intraoperatively for punctate bleeding of the fragments. Although MRI and intraoperative findings matched in 19 patients, there was no correlation in 13 patients. While 7 of these latter patients showed normal MRI but no punctate bleeding during the operation, the remaining 6 had preoperative MRI of avascularity but punctate bleeding during the operation. After internal fixation and bone grafting, all but 1 of these 13 patients achieved union. We conclude that the diagnosis of avascular necrosis should only be made when both MRI and intraoperative findings indicate avascularity. Received: 5 October 1998     

Use of the Medial Femoral Condyle Vascularized Bone Flap in Traumatic Avascular Necrosis of the Navicular: A Case Report

The medial femoral condyle vascularized bone flap has a high success rate in published literature regarding its use in nonunions and avascular necrosis of the upper and lower extremities. It is reported to have minimal donor site morbidity and the ability to provide structural support and torsional strength to load-bearing areas. The flap has found particular success in the treatment of scaphoid nonunions. The tarsal navicular, similar to the scaphoid, is largely articular cancellous bone with little surface area for vascular inflow. These anatomic features make the navicular prone to nonunion and avascular necrosis in traumatic scenarios. We describe a case of nonunion and avascular necrosis of the tarsal navicular occurring as sequelae of a high-impact midfoot injury sustained in an automobile accident. After an initial attempt at open reduction and internal fixation with midfoot bridge plating, subsidence and nonunion resulted. An attempt at arthrodesis of the talonavicular and naviculocuneiform joints was then undertaken. This too failed, leading to the development of additional collapse and avascular necrosis. The site was treated with a medial femoral condyle vascularized bone flap. In this single case, the patient returned to pain-free ambulation and reported excellent outcomes and functional capacity. Although we present a successful case, a larger case series is necessary to establish the use of this flap as a reliable option for the treatment of nonunion and avascular necrosis of the tarsal navicular.     

Radiographic evaluation of vascularity in scaphoid nonunions: A review

Scaphoid fractures, particularly those that occur more proximally, are unreliable in achieving union due to the retrograde blood supply of the scaphoid bone. Vascular compromise is associated with the development of nonunions and avascular necrosis of the proximal pole. Due to the tenuous blood supply of the scaphoid, it is imperative that the vascularity be assessed when creating diagnostic and treatment strategies. Early detection of vascular compromise via imaging may signal impending nonunion and allow clinicians to perform interventions that aid in restoring perfusion to the scaphoid. Vascular compromise in the scaphoid presents a diagnostic challenge, in part due to the non-specific findings on plain radiographs and computed tomography. Magnetic resonance imaging techniques have dramatically improved our ability to assess the blood supply to the scaphoid and improve time to intervention. This review aims to summarize these advances and highlights the importance of imaging in assessing vascular compromise in scaphoid nonunion and in reperfusion following surgical intervention.     

Your diagnosis? Scaphoid fracture

Fractures of the scaphoid are the most common carpal bone fracture. With careful management, prognosis is excellent. Imaging is critical, not only for early diagnosis, but also for monitoring patients after initial treatment to detect unstable fractures, the common complications of nonunion and avascular necrosis, and the need for surgical treatment.     

Healing of a scaphoid nonunion using human bone morphogenetic protein

A chronic nonunion of a proximal pole fracture of the scaphoid was treated by curettage of the nonunion, single K-wire fixation, and implantation of 50 mg of human bone morphogenetic protein followed by 12 weeks of cast immobilization without any conventional corticocancellous bone grafting or rigid screw fixation. Radiographs showed signs of bony healing by 12 weeks and a magnetic resonance imaging scan 6 years after surgery showed no signs of avascular necrosis. The potential future applications of human bone morphogenetic protein in hand surgery are discussed.     

Corticocancellous grafting and an AO/ASIF lag screw for nonunion of the scaphoid. A retrospective analysis

We report our experience in 42 patients, using corticocancellous bone grafts and lag screw fixation for un-united scaphoid fractures. Using a grading system, we analysed the suitability of the method for three types of nonunion. We recommend the operation for the treatment of scaphoid nonunion, except where there is avascular necrosis of the proximal pole.     

Role of conventional and vascularized bone grafts in scaphoid nonunion with avascular necrosis: A canine experimental study

The effectiveness of vascularized and conventional bone grafts in the treatment of carpal fracture nonunion with avascular necrosis was evaluated in 12 adult dogs. The proximal third of the radiocarpal bone was removed bilaterally and frozen in liquid nitrogen. Its replacement, leaving a 4-mm gap, simulated a scaphoid fracture nonunion with avascular necrosis. A dorsal radius inlay graft was placed across the gap. The graft was nonvascularized, or conventional on one side, and vascularized with a reverse-flow arteriovenous pedicle on the other. Following a healing period, quantitative assessment of bone blood flow, fracture healing, and bone remodeling was conducted. Seventy-three percent of the vascularized grafts and none of the conventional grafts healed. At 6 weeks, bone blood flow in the proximal pole was significantly higher on the side of the vascularized graft. Quantitative histomorphometry of the avascular proximal segment demonstrated significantly higher levels of fluorochrome-labeled osteoid- and osteoblast-covered trabecular surfaces on the vascularized graft side. These experimental data support the potential clinical application of pedicled reverse-flow vascularized grafts in the treatment of carpal fracture nonunions with avascular necrosis, including proximal pole scaphoid nonunions.     

桡动脉茎突返支为蒂桡骨茎突骨瓣植入术治疗舟骨骨折不愈合

目的总结以桡动脉茎突返支为蒂的桡骨茎突骨瓣移位治疗舟骨骨折不愈合的临床效果。方法2000年3月~2005年6月,对18例舟骨骨折不愈合的患者,以桡动脉茎突返支为蒂在桡骨茎突掀起1.5cm×3.5cm×0.5cm的骨瓣,植入沿舟骨纵轴跨越骨折线所凿同等大小的骨槽内进行治疗。其中男15例,女3例。年龄18~39岁。舟骨腰部骨折11例,近侧1/3骨折7例,其中5例舟骨近端骨折块伴缺血坏死。腕关节活动疼痛,尤以背伸及桡偏时明显,鼻烟窝处有压痛,腕关节活动受限,X线片示10例患者有骨折端硬化及囊性变,骨折线明显加宽。结果术后18例舟骨骨折均愈合,其中5例合并缺血坏死的舟骨骨折块重新成活,骨折平均愈合时间为4个月。术后获随访1~5年,患者腕关节活动良好,腕背伸时无疼痛,日常生活和工作无影响。结论采用桡动脉茎突返支为蒂的桡骨茎突骨瓣移位治疗舟骨骨折不愈合及近端骨折块缺血坏死,操作简便,治疗有效,具有一定临床应用价值。     

Preiser’s disease

Preiser’s disease is a rare condition involving avascular necrosis of the scaphoid, in part or in whole. Diagnosis currently is made most frequently by standard radiographs and magnetic resonance imaging (MRI). Treatment options are varied because no large series of comprehensive results has been reported. Vascularized or conventional bone grafting, proximal row carpectomy, and scaphoid excision/4 bone fusion are performed most commonly. If possible, every attempt to save the scaphoid should be made.     

A capsular-based vascularized distal radius graft for proximal pole scaphoid pseudarthrosis

PURPOSE: To evaluate the clinical results of the application of a capsular-based dorsal distal radius vascularized bone graft in scaphoid proximal pole nonunions. METHODS: Thirteen patients with symptomatic nonunion at the proximal pole of the scaphoid (10 with avascular necrosis) were treated and reviewed retrospectively. The vascularized bone graft was harvested from the distal aspect of the dorsal radius and was attached to a wide distally based strip of the dorsal wrist capsule. It was inserted press-fit into a dorsal trough across the nonunion site after scaphoid fixation with a Herbert screw. RESULTS: After a mean follow-up period of 19 months 10 of the 13 nonunions (8 of the 10 with avascular necrosis) achieved solid bone union. No complications other than the 3 persistent nonunions occurred. CONCLUSIONS: Results of the use of a capsular-based vascularized bone graft from the distal radius for proximal pole scaphoid nonunions compare favorably with the results of pedicled or free vascularized grafts. It is a simple technique that eliminates the need for dissection of small-caliber pedicle or microsurgical anastomoses. No donor site morbidity was observed. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.     

Total volar extrusion of the lunate and scaphoid proximal pole with concurrent scapholunate dissociation

This article describes a case of a 24-year-old man with a total volar extrusion of the lunate and scaphoid proximal pole with concurrent scapholunate dissociation. The viability of the lunate and the proximal pole of the scaphoid are at high risk in this type of injury. Scaphoid nonunion, avascular necrosis of the lunate and proximal pole of the scaphoid, and carpal instability are inevitable unless the blood supply is restored. Thus, proximal row carpectomy at injury may be an acceptable option to avoid these complications and late sequelae, including chronic wrist pain and dysfunction. However, the authors attempted accurate reduction of the extruded bones and internal fixation.Final radiographs and magnetic resonance imaging 12 years postoperatively showed healing without avascular necrosis. Carpal indices involving the scapholunate angle, radiolunate angle, and carpal height ratio were similar in both wrists without evidence of carpal instability or collapse. Range of motion and grip power were 75% and 76%, respectively, compared with those of the uninjured wrist. Clinical scores showed good results, and the patient reported no pain during activities of daily living and was satisfied with his surgical results. Open reduction and internal fixation can be a viable option in this rare pattern of injury.     

Surgical treatment of nonunion and avascular necrosis of the proximal part of the scaphoid in adolescents

BACKGROUND: The purpose of this retrospective study was to examine the clinical and radiographic results of treatment of proximal scaphoid nonunion and avascular necrosis with vascularized bone graft from the distal part of the radius in adolescent patients. METHODS: Between 1993 and 1996, three adolescents with a proximal scaphoid nonunion and avascular necrosis underwent vascularized bone-grafting and internal fixation. The mean age at the time of the fracture was 14.8 years (14.4, 14.6, and 15.3 years), and the mean time interval between the fracture and the surgery was 19.3 months (six, seventeen, and thirty-five months). We retrospectively reviewed all available clinical and radiographic data from the time of fracture to the time of the last follow-up. All patients were examined clinically and radiographically at the time of the review, at a mean of 5.5 years (five, five, and 6.5 years) after surgery. RESULTS: All fractures healed at a mean of 3.4 months (2.75, 3.0, and 4.5 months) postoperatively. Final follow-up radiographs showed union and revascularization of the proximal part of the scaphoid with no evidence of degeneration of the radiocarpal joint. None of the patients had limiting pain or scapholunate instability demonstrated on physical or radiographic examination. Dorsiflexion and radial deviation of the affected wrist were decreased by a mean of 22 degrees (10 degrees, 22 degrees, and 35 degrees ) and 15 degrees (5 degrees, 20 degrees, and 20 degrees ), respectively, compared with those of the normal wrist. CONCLUSION: Grafting with vascularized radial bone is an effective treatment, leading to union and good function, for nonunion and avascular necrosis of the proximal part of the scaphoid in adolescents.