The black sand. / Den svarte sanden.

Millions of people are walking around with titanium implants in their body. What makes this metal so well-suited for medical use?

Excellent results after bone grafting and K-wire fixation for scaphoid nonunion surgery in skeletally immature patients: a midterm follow-up study of 11 adolescents after 6.9 years.

OBJECTIVES: Scaphoid nonunion is relatively rare in children and adolescents, and no long-term follow-up has been reported. DESIGN: Retrospective follow-up study. PATIENTS: Eleven patients (10 boys and 1 girl), mean 15.2 (13.9-15.9) years of age, with scaphoid nonunion and open growth plates were operated with bone grafting, Kirschner-wire fixation and 12 weeks of cast immobilization. MAIN OUTCOME MEASUREMENTS: Bony union, degenerative wrist changes, and restoration of the carpal architecture were assessed with CT and radiographs. Clinical parameters included active range of motion, grip strength, key pinch strength, and subjective outcome scores (quick disabilities of arm, shoulder and hand (DASH), visual analog scale). RESULTS: The patients were followed up after mean 6.9 (3.1-15.1) years; all patients attended. Radiographs and CT confirmed healing of all nonunions, the carpal anatomy was restored, and the wrists were rated as 0 according to the scaphoid nonunion advanced collapse, without degenerative changes. The clinical result was excellent with visual analog scale at rest = 1, at activity = 6, and quick DASH score = 3.3. Active range of motion and grip strength were insignificantly reduced (14 degrees and 2 kg); the key pinch strength remained similar. CONCLUSIONS: Healing of a scaphoid nonunion can be expected in adolescents after open reduction, Kirschner-wire fixation, bone grafting, and plaster immobilization, resulting in pain relief and excellent wrist function without degenerative changes after longer term follow-up. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Scaphoid non-unions, where do they come from? The epidemiology and initial presentation of 270 scaphoid non-unions.

Scaphoid injury and subsequent non-union is a well documented and researched subject. This article gives an overview of the epidemiology and results of the patients we have treated for scaphoid non-union at a University Hospital. 283 scaphoid non-unions in 268 patients (83% men) were operated upon, 230 as a primary and 47 as a secondary. The median age at time of surgery was 27 years. One-third of the non-unions were located in the proximal part of the scaphoid and the remaining two-thirds in the middle part. Of the 146 patients (55%) who contacted a doctor at the time of injury, 53 fractures where diagnosed (20%). Fourteen (5%) were operated primarily while 39 (15%) (seven dislocated) were immobilized in plaster casts. Thirty-two (12%) were under the age of 16 at the time of injury. The average time from the injury to the initial non-union surgery was 1.5 years with 2.8 years to the second procedure. The risk of osteoarthritis increased time from injury to surgery (both primary and secondary procedures). The greatest potential for the reduction of scaphoid non-union is an increased awareness amongst younger men. There is also potential for improved accuracy in the diagnosis of scaphoid fractures (better clinical tests, the use of radiographs, CTs and MRIs) in order to identify the fracture and evaluate dislocation at the initial injury. Early diagnosis and treatment of fractures and non-unions will reduce the development of degenerative wrist changes.

Long-term results of scaphoid nonunion surgery: 50 patients reviewed after 8 to 18 years.

OBJECTIVES: Untreated scaphoid nonunions are a hazard to the wrist, resulting in deteriorating function and radiologic degenerative changes with increasing time. Long-term results after surgery of scaphoid nonunion reporting clinical, radiologic, and subjective outcomes are scarce. DESIGN: Retrospective follow-up study. PATIENTS: From 1990 to 1998, 53 patients were operated on for persistent scaphoid nonunion; three patients were excluded from the follow-up (one expelled foreigner, another died of an unrelated cause, one never appeared after surgery), leaving 50 patients eligible for follow-up. INTERVENTION: All patients were operated on with open reduction and internal fixation; the majority also received a bone graft. MAIN OUTCOME MEASUREMENTS: Radiology and computed tomography verified union, degenerative wrist changes, and final salvage treatment. Range of motion, grip strength, key pinch, and subjective outcome (QuickDASH, visual analog scale). RESULTS: Fifty patients were followed up after a mean of 12.2 years (standard deviation [SD], 3.0), 47 by clinical and radiologic examination; three were interviewed by telephone and completed QuickDASH and visual analog scale forms. Union was achieved in 45 of 50 scaphoids and an additional two after a second attempt. Five patients (one persistent and four healed nonunions) underwent salvage procedures. Grip strength (41 vs 45 kg, P = nonsignificant), key pinch (11.5 vs 12.4, P = nonsignificant), and active range of motion (186° vs 214°, P < 0.001) were slightly reduced compared with the uninjured side. The subjective outcome was good (mean visual analog scale = 7, mean QuickDASH = 9.1). Minor degenerative changes were seen in nine wrists at surgery and 22 at follow-up. CONCLUSION: Healing of a scaphoid nonunion provides long-term pain relief, excellent wrist function, and halts degenerative changes in the majority of patients. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

New concept for total wrist replacement.

Wrist prostheses have never achieved the sort of clinical outcomes found with those of hips and knees. We have developed a novel uncemented modular wrist prosthesis with screw fixation, metal-on-metal coupling, and ball-and-socket articulation. Eight patients admitted for wrist arthrodesis to treat primary or secondary osteoarthritis (not rheumatoid) were operated on. The prosthesis reduced the amount of bone removed and spared the distal radioulnar joint. After 7 to 9 years we found that the fixed centre of the ball-and-socket articulation provided good stability and mobility, and relief of pain and grip strength were satisfactory. We saw no luxations, metacarpal fractures or cut-outs, or mechanical failures of the implants. Two distal screws loosened (revised with new distal screws), and one early inflammation and one late infection occurred (revised to arthrodesis). We propose modifications to the implant with reduction in the diameter of the screws and the height of the threads, and rounding of the distal tip. The technique should include release of the third carpometacarpal joint, alignment of the capitate and the third metacarpal, and arthrodesis of the joint with bone chips.

Different patterns of bone fixation with hydroxyapatite and resorbable CaP coatings in the rabbit tibia at 6, 12, and 52 weeks.

Applying bioactive coatings on orthopedic implants can increase the fixation and long-term implant survival. In our study, we compared a resorbable electrochemically deposited calcium phosphate coating (Bonit®) to a thin (40 µm) plasma-sprayed hydroxyapatite (HA) coating, applied on grit-blasted screw-shaped Ti-6Al-4V implants in the cortical region of rabbit tibia, implanted for 6, 12, and 52 weeks. The removal torque results demonstrated stronger bone-to-implant fixation for the HA than Bonit-coated screws at 6 and 12 weeks. After 52 weeks, the fixation was in favor of the Bonit-coated screws, but the difference was statistically insignificant. Coat flaking and delamination of the HA with multinucleated giant cell activity and bone resorption observed histologically seemed to preclude any significant increase in fixation comparing the HA implants at 6 versus 12 weeks and 12 versus 52 weeks. The Bonit-coated implants exhibited increasing fixation from 6 to 12 weeks and from 12 to 52 weeks, and the coat was resorbed within 6 weeks, with minimal activity of multinucleated giant cells or bone resorption. A different fixation pattern was observed for the two coatings with a sharper but time limited increase in fixation for the HA-coated screws, and a slower but more steadily increasing fixation pattern for the Bonit-coated screws. The side effects were more serious for the HA coating and limiting the expected increase in fixation with time.