Die Korrektur von posttraumatischen Fehlstellungspseudarthrosen der Tibia mit dem Taylor Spatial Frame

[Three-dimensional analysis of posttraumatic tibial shaft malunion and correction based on the healthy, contralateral leg]

OBJECTIVE

Three-dimensional (3D) analysis and implementation with patient-specific cutting and repositioning blocks enables correction of complex tibial malunions. Correction can be planned using the contralateral side or a statistical model. Patient-specific 3D-printed cutting guide blocks enable a precise osteotomy and reduction guide blocks help to achieve anatomical reduction. Depending on the type and extent of correction, fibula osteotomy may need to be considered to achieve the desired reduction.

CONTRAINDICATIONS

a) Poor soft tissue (flap surgery, adherent skin in field of operation); b) infection; c) peripheral artery disease (stage III and IV classified according to Fontaine, critical transcutaneous oxygen partial pressure, TcPO2); d) general contraindication to surgery.

SURGICAL TECHNIQUE

Before surgery, a 3D model of both lower legs is created based on computed tomography (CT) scans. Analysis of the deformity based on the contralateral side in a 3D computer model (CASPA) and planning of the osteotomy. If the contralateral side also has a deformity, a statistical model can be used. Printing of patient-specific guides made of nylon (PA2200) for the osteotomy and reduction. Surgery is performed in supine position, antibiotic prophylaxis, thigh tourniquet, which is used as needed. Ventrolateral approach to the tibia. Attachment of the patient-specific osteotomy guide, performance of the osteotomy. Reduction using the guide. Fibula osteotomy through a lateral approach is performed if the reduction of the tibia is hindered by the fibula. This can be performed freehand or with patient-specific guides. Wound closure.

POSTOPERATIVE MANAGEMENT

Compartment monitoring. Passive mobilization of the ankle in the cast as soon as the wound healing has progressed. Partial weightbearing in a lower leg cast for at least 6-12 weeks, depending on the routinely performed radiographic assessment 6 weeks postoperatively. Thromboprophylaxis with low molecular weight heparin until cast removal.

RESULTS

Patient-specific correction of malunions are generally good. This could be confirmed for distal tibial corrections. For tibial shaft deformities, the final results are still pending. Preliminary results, however, show good feasibility with a pseudarthrosis rate of 10% without postoperative infection.

Accuracy of radiographic measurement techniques for the Taylor spatial frame mounting parameters

Aim

The correction accuracy of the Taylor Spatial Frame (TSF) fixator depends considerably on the precise determination of the mounting parameters (MP). Incorrect parameters result in secondary deformities that require subsequent corrections. Different techniques have been described to improve the precision of MP measurement, although exact calculation is reportedly impossible radiologically. The aim of this study was to investigate the accuracy of intraoperative and postoperative radiographic measurement methods compared to direct MP measurement from TSF bone mounting.

Methods

A tibial Sawbone® model was established with different origins and reference ring positions. First, reference MPs for each origin were measured directly on the frame and bone using a calibrated, digital vernier calliper. In total 150 MPs measured with three different radiographic measurement techniques were compared to the reference MPs: digital radiographic measurements were performed using soft-copy PACS images without (method A) and with (method B) calibration and calibrated image intensifier images (method C).

Results

MPs measured from a non-calibrated X-ray image (method A) showed the highest variance compared to the reference MPs. A greater distance between the origin and the reference ring corresponded to less accurate MP measurements with method A. However, the MPs measured from calibrated X-ray images (method B) and calibrated image intensifier images (method C) were intercomparable (p = 0.226) and showed only minor differences compared to the reference values but significant differences to method A (p < 0,001).

Conclusion

The results demonstrate that MPs can be accurately measured with radiographic techniques when using calibration markers and a software calibration tool, thus minimizing the source of error and improving the quality of correction.

Eccentric Taylor spatial frame placement for the correction of femoral fracture deformity: a novel technique

The treatment of post-traumatic femoral deformity with circular frames can be difficult both for the patient and for the surgeon. Patients frequently suffer from residual knee stiffness, and the cumbersome location of the frame can even result in psychiatric problems such as depression and anxiety during their treatment. Here we describe a novel technique of constructing the Taylor spatial frame (TSF) eccentrically from the femur to allow the same level of comfort as a monolateral external fixator, while applying trigonometric principles to successfully retain the utility of the TSF prescription software. Deformity correction and fracture compression can therefore still be achieved in a controlled and predictable manner on an outpatient basis.

[Correction of posttraumatic lower leg deformities using the Taylor Spatial Frame]

OBJECTIVE

Correction of posttraumatic lower leg deformities using percutaneous osteotomy, external fixation with a ring fixator, and computer-assisted gradual correction with the Taylor Spatial Frame (TSF).

INDICATIONS

Posttraumatic lower leg deformities not suitable for acute correction and internal fixation or deformities that are suitable but have a significantly increased risk for complications: deformities with poor soft tissue coverage, rigid deformities that require gradual correction, complex mulitplanar deformities, deformities with shortening, and periarticular juvenile deformities.

CONTRAINDICATIONS

Posttraumatic lower leg deformities which are suitable for acute correction and internal fixation are also suitable for deformity correction using the TSF. In these cases, however, we recommend acute correction and internal fixation in order to improve the patient comfort. Lack of patient compliance for self-contained correction and pin care.

SURGICAL TECHNIQUE

Percutaneous fixation of the TSF rings to the main fragments using transosseous K-wires and half pins (hybrid fixation). Percutaneous osteotomy of the tibia either by drilling across both cortices and completion of the osteotomy using an osteotome (DeBastiani method) or by using the Gigli saw with preservation of the periostal envelope. Connection of both rings with six oblique telescopic struts via universal joints (hexapod platform). Computer-assisted planning of the correction.

POSTOPERATIVE MANAGEMENT

Gradual postoperative correction of the deformity by changing the strut lengths according to the correction plan. Strut changes, if required. Osseous consolidation of the osteotomy site with the TSF or revision to internal fixation.

RESULTS

The correction of posttraumatic lower leg deformities using the TSF was performed in 6 cases. The mean deformity was 15° (12-22°) in the frontal plane and 6° (4-8°) in the sagittal plane. The correction time was 19 days (14-22 days). The deviation between planned and achieved correction was 0-3° in the frontal plane and 0-2° in the sagittal plane. The osseous consolidation of the osteotomy site was carried out in the TSF in 5 cases with a mean external fixation time of 112 days (94-134 days). In one case, the TSF was removed after the correction and the osteotomy site was fixed using an intramedullary nail. Pin site infections were observed in 3 cases. There were no further complications. The treatment goal was achieved in all cases. The examination at final follow-up was performed after 1 year. All patients were able to walk without walking aids and with no pain at that time. They were able to perform all of their activities of the daily life and their leisure activities without limitations.

Taylor spatial frame in severe foot deformities using double osteotomy: technical approach and primary results

PURPOSE

The treatment of severe foot deformities in children or adolescents is complex and demanding to the surgeon. This paper describes the technical strategy of using a Taylor spatial frame and reports on the functional outcome.

METHODS

The Taylor spatial frame was used by a single surgeon in patients with severe foot deformities. Seven patients with eight severe deformities were treated. Mean patient age at surgery was 15.1 (9-29) years. A double Taylor spatial frame reconstruction was mounted to the limb. All patients had a midtarsal osteotomy and an additional inverse dome-shaped calcaneus osteotomy. Assessed measures were pre- and postoperative deformity and associated complications and clinical results according to Ferreira et al.

RESULTS

Mean follow-up was 576.5 (359-987) days. The final functional outcome according to Ferreira was good in seven cases, fair in none, and poor in one. Early complications included pin-tract infection, temporary hypoesthesia, and temporary shortening of the tendon of the M. flexor digitorum. At follow-up there was no deformity recurrence.

CONCLUSION

In children or adolescents, the innovative treatment using the Taylor spatial frame and a double osteotomy allows joint-preserving correction of severe foot deformities. However, the complication rate is relatively high due to the severely deformed feet. Furthermore, the Taylor spatial frame is expensive. Thus, this treatment is only recommended for severe foot deformities and should be handled by experienced orthopedic surgeons.

Correction of severe foot deformities using the Taylor spatial frame

BACKGROUND

This study was conducted to evaluate the treatment of severe foot deformities using the Taylor spatial frame.

MATERIALS AND METHODS

The treatment of seven patients with nine severe foot deformities was reviewed. The mean age of the patients at surgery was 16 years with a mean followup of 21.5 months. The following parameters were assessed: etiology of deformity, date of surgery, surgical procedure, age at surgery, previous surgical or conservative treatments, preoperative symptoms, preoperative and postoperative deformity and affected side, complications during correction, duration of TSF, duration of hospital stay, occurrence of secondary osteoarthritis, recurrence of deformity, surgical revisions or subsequent surgeries. The pre- and postoperative deformity was assessed clinically. The final outcome was categorized as good, fair, or poor.

RESULTS

The results were good in eight feet and poor in one foot. Early complications included pin tract infection, temporary hypoesthesia and temporary shortening of the tendon of the flexor digitorum longus. Recurrence of deformity occurred in no patient. One patient required a subtalar arthrodesis for symptomatic, secondary osteoarthritis in one foot.

CONCLUSION

The present study showed that TSF is a viable solution to correct severe foot deformities but we believe a surgeon should be aware of the possible complications.

Hexapodal external fixation in the management of children tibial fractures

Some tibial fractures in children require surgical osteosynthesis, mostly achieved by an internal fixation. Indications for external fixation in the management of tibial fractures in children are limited to specific clinical situations when conventional treatments are contraindicated. The aim of this study is to report the results of tibial fractures management by hexapodal external fixation. Eleven children were included in this study and all of them were treated by a specific hexapodal external fixator, with a 12-month mean follow-up. In the whole series, initial deformities were perfectly corrected in nine cases, two patients showed residual deformity that did not require further surgery. The mean time for external fixation was 98 days. Hexapodal external fixation seems to be a simple and effective definitive method for the correction of three-dimensional traumatic deformities requiring surgical stabilization. Long-term follow-up will be necessary to evaluate residual deformities at the end of patient's growth.