Der Unfallchirurg
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The most important goals of scaphoid reconstruction in pseudarthrosis are correction of the humpback deformity, the realignment of the proximal carpal row and the bony union of the scaphoid. Therefore, in most cases bone grafting is required. To increase the healing rate and to improve vascularization, several kinds of vascularized bone grafts have been developed. ⋯ The use of vascularized grafts is still a matter of controversy, since their superiority is still unproven compared to nonvascularized grafts, which also achieved 100% fusion rates in several series. They are indicated in secondary procedures after failed reconstruction and nonunion with small avascular proximal pole fragments. Since no evidence-based guidelines exist, this article provides an experience-based treatment algorithm for scaphoid nonunion with special consideration to vascularized bone grafts.
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Untreated scaphoid nonunion as a rule results in subsequent scaphoid nonunion advanced collapse (SNAC) wrist. While reconstructive treatment of the scaphoid in association with resection of the styloid process of the radius is still promising in stage I SNAC wrist, salvage procedures are available for higher degrees of SNAC wrist to reduce pain and to preserve the function of the wrist. Denervation, proximal row carpectomy and partial wrist fusion maintain wrist mobility. Total wrist arthrodesis and total wrist arthroplasty are salvage procedures in cases of panarthritis or failed motion-preserving procedures.
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Among the carpal bones the scaphoid (Os scaphoideum) is the most important. The most frequent fracture of the carpus is a fracture of the scaphoid bone. The frequently occurring absence of healing of these fractures as well as unhealed ruptures of the ligament complex between the scaphoid and lunate, lead to the most severe biomechanical and thus the most severe clinical changes of the wrist. The detailed anatomy of the scaphoid, blood flow, ligament attachments, injury mechanisms and pathobiomechanics are described and illustrated.
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Fractures of the scaphoid bone are common but can easily be overlooked in standard X‑rays. Inadequate diagnostics and therefore inappropriate treatment of scaphoid fractures often leads to problems in healing with formation of non-union and painful osteoarthritis of the wrist. ⋯ The main statements are that in cases of a clinically suspected scaphoid fracture, staged diagnostics including radiographs, computed tomography (CT) and when necessary magnetic resonance imaging (MRI) should be applied to confirm or exclude a fracture. Further treatment in the case of a fracture is planned according to a CT-based classification. There are fracture types that can be treated either conservatively or operatively and there are other fracture types that always require operative fixation. The operative technique depends on the exact fracture geometry. For osteosynthesis, cannulated headless compression screws are mostly used.
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Patellar fractures are a relatively rare entity with an prevalence of 1%. Preoperative computed tomography has gained a significant role as a diagnostic tool for patellar fractures in recent years. It enables an exact assessment of the fracture and helps in the decision making for the correct treatment procedure. ⋯ In this context, the results of angle stable plate fixation are promising in terms of functional outcome and lower complication rates. The proven tension band fixation using K‑wires or cannulated screws continues to be widespread in clinical practice and retains significance for simple patellar fractures. The use of polyethylene thread material instead of steel wire has shown advantages in biomechanical studies but the clinical application is more restrained.