Kahnbeinfrakturen - wann operativ, wann konservativ? CT-basierte Klassifikation

[Clinical and imaging methods in diagnostics of scaphoid fracture and non-union]

Clinical and radiological diagnostics are the base of a differentiated treatment of carpal disorders. With special regard to diagnostics of the scaphoid, not only the choice and the correct implementation of the imaging methods are crucial, but also their methodical limitations have to be taken into account. No other common fracture is more often undiagnosed, because neglected or overlooked. Concomitantly, delayed or untreated scaphoid fractures require demanding therapies in the sequel and may lead to functional restrictions in the long-term. This review article aims to discuss the clinical and imaging diagnostics for scaphoid fractures and non-union.

Multiplanar reformation computed tomography for carpal malalignment

Correct interpretation of scaphoid axial length and carpal malalignment is difficult owing to the complex geometry of the scaphoid. Traditional measurements, such as the scapholunate angle and radiolunate angle, have shown limited reproducibility. To improve the assessment of these measurements, we used multiplanar reformation computed tomography with added average intensity projection. Four measurements for scaphoid morphology and carpal alignment were independently measured by four observers on computed tomography scans of 39 consecutive patients who were treated conservatively for scaphoid fracture. Fleiss's kappa for categorical results showed substantial agreement for the measurements of the scapholunate and radiolunate angles. Intraclass correlation coefficients were significant for measurements of the axial length, scapholunate angle and radiolunate angle. Our results suggest that multiplanar reformation computed tomography with added average intensity projection is a reliable technique for assessment of scaphoid morphology and carpal alignment. Level of evidence: II.

Functional outcome and cost-effectiveness of pulsed electromagnetic fields in the treatment of acute scaphoid fractures: a cost-utility analysis

Background

Physical forces have been widely used to stimulate bone growth in fracture repair. Addition of bone growth stimulation to the conservative treatment regime is more costly than standard health care. However, it might lead to cost-savings due to a reduction of the total amount of working days lost. This economic evaluation was performed to assess the cost-effectiveness of Pulsed Electromagnetic Fields (PEMF) compared to standard health care in the treatment of acute scaphoid fractures.

Methods

An economic evaluation was carried out from a societal perspective, alongside a double-blind, randomized, placebo-controlled, multicenter trial involving five centres in the Netherlands. One hundred and two patients with a clinically and radiographically proven fracture of the scaphoid were included in the study and randomly allocated to either active bone growth stimulation or standard health care, using a placebo. All costs (medical costs and costs due to productivity loss) were measured during one year follow up. Functional outcome and general health related quality of life were assessed by the EuroQol-5D and PRWHE (patient rated wrist and hand evaluation) questionnaires. Utility scores were derived from the EuroQol-5D.

Results

The average total number of working days lost was lower in the active PEMF group (9.82 days) compared to the placebo group (12.91 days) (p = 0.651). Total medical costs of the intervention group (€1594) were significantly higher compared to the standard health care (€875). The total amount of mean QALY’s (quality-adjusted life year) for the active PEMF group was 0.84 and 0.85 for the control group. The cost-effectiveness plane shows that the majority of all cost-effectiveness ratios fall into the quadrant where PEMF is not only less effective in terms of QALY’s but also more costly.

Conclusion

This study demonstrates that the desired effects in terms of cost-effectiveness are not met. When comparing the effects of PEMF to standard health care in terms of QALY’s, PEMF cannot be considered a cost-effective treatment for acute fractures of the scaphoid bone.

Trial registration

Netherlands Trial Register (NTR): NTR2064

CT scan-evaluated outcome of pulsed electromagnetic fields in the treatment of acute scaphoid fractures: a randomised, multicentre, double-blind, placebo-controlled trial

We hypothesised that the use of pulsed electromagnetic field (PEMF) bone growth stimulation in acute scaphoid fractures would significantly shorten the time to union and reduce the number of nonunions in a randomised, double-blind, placebo-controlled multicentre trial. A total of 102 patients (78 male, 24 female; mean age 35 years (18 to 77)) from five different medical centres with a unilateral undisplaced acute scaphoid fracture were randomly allocated to PEMF (n = 51) or placebo (n = 51) and assessed with regard to functional and radiological outcomes (multiplanar reconstructed CT scans) at 6, 9, 12, 24 and 52 weeks. The overall time to clinical and radiological healing did not differ significantly between the active PEMF group and the placebo group. We concluded that the addition of PEMF bone growth stimulation to the conservative treatment of acute scaphoid fractures does not accelerate bone healing.

Union rates after proximal scaphoid fractures; meta-analyses and review of available evidence

We carried out a comprehensive analysis of publications to investigate long term union rates of acute proximal scaphoid fractures. Of 1147 acute scaphoid fractures managed nonoperatively that were available for analysis, 67 (5.8%) were proximal. Amalgamating publications revealed that 34% of acute proximal scaphoid fractures progress to nonunion when managed nonoperatively. A meta-analysis showed that the relative risk of nonunion for these fractures is 7.5 compared with more distal fractures, also managed nonoperatively. More trials are needed to allow direct comparison of acute proximal scaphoid fractures managed operatively and nonoperatively. Power calculations indicate that 76 cases will need to be recruited for such a study. Currently, the proximal scaphoid is defined inconsistently. To avoid misclassification we suggest the region is defined as the proximal fifth of the bone, and computer tomography is used during follow-up.

Treatment of acute scaphoid fractures in the athlete

Scaphoid fractures in athletes can be very disabling and may limit successful and early return to play. Typically, the mechanism of injury is a fall onto an outstretched hand or a direct blow; the patient will present with swelling, limited motion, and snuffbox tenderness. Multiple-view plain images will very often reveal the diagnosis. In addition, diagnostic modalities such as CT scanning and MRI are helpful in better defining the architecture of the fracture and vascularity of the scaphoid, and diagnosing occult fractures. Early and accurate diagnosis is critical to help ensure appropriate treatment and optimal outcome. Traditional treatment of stable nondisplaced fractures remains cast immobilization. However, if early return to play is desired operative fixation may be warranted. For nondisplaced fractures operative techniques include open reduction and internal fixation (ORIF), and percutaneous fixation through a dorsal or volar approach. Arthroscopy can be used as an adjunct to the percutaneous technique. For displaced fractures, the preferred technique remains ORIF through either a volar or dorsal approach. Considerations in treatment type are based on the stability and location of the fracture as well as patient issues such as compliance and the need for return to play. With appropriate diagnosis and individualization of treatment, scaphoid fractures can be successfully managed in most athletes with few or no long-term sequelae.

Skaphoidfraktur und -pseudarthrose

Scaphoid fractures, which involve approximately two-thirds of all wrist injuries, are often not detected during initial radiographic examination. By using high-resolution CT and dedicated MRI, it is possible to recognize scaphoid fractures soon at the first diagnostic approach and to assess fragment stability. CT imaging provides all the relevant information of the fracture extent and of the fracture healing in the follow-up. MRI is most sensitive in the detection of scaphoid fractures; however, fracture signs must be differentiated from those of a bone bruise. Both the initially overseen scaphoid fracture and the unsuccessful healing can lead to the natural history of scaphoid nonunion. In the injured scaphoid, CT imaging is essential for depicting the osseous morphology, whereas contrast-enhanced MRI is crucial for assessing the viability of the proximal fragment.