A computational approach to the "optimal" screw axis location and orientation in the scaphoid bone.

PURPOSE: The development of small cannulated screws permitted minimally invasive percutaneous fixation of acute scaphoid fractures. There are known mechanical advantages to increased screw length and central screw placement, as well as documented deleterious effects of screw malposition, including articular protrusion, proximal pole fracture, and nonunion. The purpose of this study was to compare 2 methods of calculating a screw axis accessible via a volar surgical approach. METHODS: To prevent screw protrusion through the surface of the scaphoid, we required the central screw axis to be contained completely within a "safe zone," defined as a 3-dimensional region located a fixed distance from the inner cortical surface. Safe zones were calculated based on computed tomography-generated models of the right scaphoid from 10 healthy subjects. Two methods for screw axis calculation were compared: (1) maximum screw length (MSL) within the safe zone and (2) a cylinder best-fit (CYL) to the safe zone. The volar approach was defined as percutaneous screw placement through the scaphoid tubercle without violation of the trapezium. Resultant screw axes were compared between the 2 methods for volar accessibility, screw length, and location of the screw axis. RESULTS: The MSL axes were completely accessible without violating the trapezium in all but 2 subjects. The average MSL axes were 11% longer than the CYL axes and passed significantly closer to the scaphoid tubercle than did the CYL axes (1.8 mm vs 6.4 mm). The MSL axes passed significantly farther (1.6 mm) from the bone centroid than did the CYL axes (0.4 mm). All 10 MSL axes were located in the central one-third of the proximal pole. CONCLUSIONS: Without violation of the trapezium, MSL axis can be attained via the volar percutaneous approach to the scaphoid. Using this approach, the ideal starting point for maximal screw length was located 1.7 mm dorsal and 0.2 mm radial to the apex of the scaphoid tubercle.

Microbial colonization of tourniquets used in orthopedic surgery.

This study analyzed tourniquets used for orthopedic surgery in our hospital to determine the frequency and type of microbial contamination. Group A tourniquets were from our main operating room, Group B tourniquets were from our ambulatory surgicenter, Group C tourniquets were unused, prepackaged, sterile tourniquets from our main operating room, and Group D tourniquets were sterilely packed tourniquets from our ambulatory surgicenter. Tourniquets from Groups A, B, C, and D had 100%, 40%, 0%, and 0% microbial growth, respectively. For Group A tourniquets, coagulase-negative staphylococci, Bacillus, and Staphylococcus aureus were present in 100%, 60%, and 20% of tourniquets, respectively. Twenty percent were contaminated either with Streptococcus sanguis, Aerococcus viridans, or Cornyebacterium species. Coagulase-negative staphylococci and Bacillus were present in 40% and 30% of Group B tourniquets, respectively. Tourniquet contamination may be a risk factor for the development of surgical site infection in orthopedic surgery.

Giant cell tumor of tendon sheath.

Neoplasms of the hand are not common. Giant cell tumor of tendon sheath (GCTTS) is the most common primary tumor of the hand. Many different theories have recently been proposed as to whether GCTTS is a neoplasm or a localized reactive process. We believe the evidence supports a neoplastic origin. Although the origin is still not proved, the presentation, diagnosis, and treatment of GCTTS have been clear for a long time.

Thumb carpometacarpal arthroscopy: a topographic, anatomic study of the thenar portal.

Arthroscopic treatment of osteoarthritis of the thumb carpometacarpal joint has been well described; however, the current site of the 2 working portals, especially the 1-R portal, may be complicated by neurovascular morbidity. This is owing to the close proximity of these portals to important nerves and vessels surrounding the carpometacarpal joint. We studied 7 cadaveric wrists to map out the topographic, anatomic, and arthroscopic position of a new thenar portal. We hypothesized that it would increase considerably the safe zone distances of the portal from vital structures of the joint compared with the traditional portals. This study showed that the thenar portal increases considerably the safe zone of the portal from the sensory branches of the radial nerve and the radial artery and does not put the motor branch of the median nerve at risk. In addition the thenar portal allows for better visualization of the carpometacarpal joint, which leads to improved ability to perform arthroscopic trapeziectomy.

Fibular nonunion after closed rotational ankle fracture.

BACKGROUND: Historically, the standard of care for minimally or nondisplaced, closed, distal fibula fractures has been short-term immobilization and progressive weightbearing. The vast majority of such patients are expected to heal with excellent functional outcome after such treatment. There exists a subpopulation of patients sustaining these fibular fractures who develop symptomatic incomplete union or nonunion despite appropriate management, and later require operative intervention to eliminate pain. METHODS: A retrospective review of 17 referred patients with rotational fibular fractures between August 1999 and July 2003 identified six persistently symptomatic distal fibular fractures after an adequate trial of conservative treatment. Due to their persistent localized pain and difficulty with ambulation, five patients underwent operative treatment of the nonunion with autologous bone grafting with plate and screw osteosynthesis. The sixth patient has refused operative intervention despite persistent symptoms. RESULTS: All six of these patients were identified as low risk for nonunion. Two fibular nonunions were found to be complete and four were partial nonunions. One hundred percent of these patients presented with a chief complaint of pain, had reproducible tenderness with palpation directly at the fracture site, and exhibited a persistent antalgic gait pattern. Four of six patients who underwent surgery noticed complete resolution of their pain and return of their normal gait within an average of 2.3 months postoperatively, with an average follow-up of 19.5 months (range, 2-53 months). CONCLUSIONS: Distal fibula nonunion appears to be a relatively common cause of persistent lateral ankle symptoms in patients who do not enjoy a satisfactory recovery after appropriate conservative treatment. The authors believe that the persistent lateral pain in such patients results from micromotion strain at the incomplete fracture union site. Surgical stabilization of fibular nonunion seems to be a reliable means of resolving these symptoms when conservative measures fail.