Introduction: Various variants of the extensor indicis (EI) have be described in the literature. We wanted to detect whether there exist any variants of the EI that may cause restricted mobility of the thumb following EI transposition to the extensor pollicis longus (EPL).

Patients & method: Intraoperatively the function of the extensor tendons of 168 hands (98 right / 70 left) of 159 patients (96 female / 63 male) were examined. The function of the muscles was simulated using a tendon-hook. For ethical reasons the approach was not extended for the study.

Results: In 34 of 168 hands 39 accessory tendons were found: 8 were localized between EPL and EI (1 from the EPL to the index; 3 extensor pollicis et indicis; 1 from the EI-muscle to the thumb; 3 to the radial extensor hood of the index). 31 accessory tendon were found ulnar to the EI (2 to the ulnar extensor hood of the index; 25 to the middle finger; 3 to the ring finger; 1 to the little finger). The EI was missing in only one hand, were a strong extensor anularis-tendon was found, which would have been suitable for EPL-reconstruction. 8 of these variants would hinder the thumb from isolated extension following EPL-reconstruction with the EI-tendon.

Conclusion: The extensor tendons should be inspected carefully through EI-transposition for reconstruction of EPL to ensure a free function of the thumb postoperatively. Small accessory tendons that may cause trouble should be cut, strong tendons should be transposed together with the EI-tendon.

Introduction: Image based navigation is able to increase precision and reduce intraoperative radiation time in drilling procedures in orthopeadic trauma indications. Due to specific anatomic conditions and necessary adequate fluoroscopic visualizing, specific indications need intraoperative 3-D fluoroscopy based navigation modalities. This kind of navigation has already been successfully used in several orthopaedic interventions. The complex anatomic structure of the scaphoid, the suggested minimal invasiveness and misplacement rates of the screws make 2-D based fluoroscopic navigation impossible. Missing options for a stable reference marker fixation at the scaphoid or carpus did not allow an intraoperative registration for the navigation. We report about the development of an adequate non invasive fixation technique of the reference marker for navigated interventions and the first implementation of 3-D fluoroscopy based scaphoid screws.

Materials and method: Fixation of the reference marker was achieved by immobilisation of the complete hand and forearm in maximum dorsal extension of the wrist. We used a completely new developed radiolucent hand fixation device (HFD) fixed nonivasively to the carpus and a conventional navigation system (Brainlab, Germany) in combination with 3-D fluoroscopic imaging (Iso-C, Siemens, Germany).

Tests were done on 10 intact specimen and the process included the initial drilling and final placement of an osteosynthetic screw. Postoperative placement was controlled with a 3-D scan. Results concerning a defined optimal screw positioning and drill failures attempts were done by another independent surgeon.

Results: All 3-D scans were done without complications. The multiplanar reconstructions allowed a proper visualisation of the scaphoid in all cases. No additional movement of the fixed extremity occurred during the operation. No registration failures were detected. An optimally defined screw placement in the scaphoid was achieved in 9 cases. Two repeated drill attempts were necessary in one case, another case needed three drill attempts. The scaphoid was never perforated.

Discussion: Our development of a new immobilizing device for the complete hand and forearm allows proper use of 3-D fluoroscopy based navigation at the scaphoid including a placement of an osteosynthetic screw. Further movements of the hand or fingers are intraoperatively only possible after the definite drill placement has been performed.

The 3-D imaging modality allows a direct control of the reduction and screw placement intraoperatively. Our tests did not include simulated fracture conditions, a general use of our new technique can now only be implemented to non displaced fracture types, while clinical and further laboratory tests have to improve our findings for all types of scaphoid fractures.

PURPOSE: A new device for intraoperative pedography was developed. The purpose of this study was to validate the introduced method with standard dynamic pedography, and to analyze the clinical benefit.

Methods: For an intraoperative introduction of standardized forces to the footsole, a device named Kraftsimulator Intraoperative Pedographie was developed.

The validation was performed in two steps: Step 1. Comparison of standard dynamic pedography (three trials, walking, third step, three trials, mid stance force pattern), static pedography in standing position (three trials) and pedography with KIOP in healthy volunteers (three trials, total force 400 N).. Step 2. Comparison between pedography in standing position, pedography with KIOP in awake and anaesthesized patients (three trials, total force 400 N).

A randomized prospective controlled study comparing treatment with and without intraoperative pedography has started on November 1, 2005. The subjects are randomized into two groups,

a) use of intraoperative pedography, versus

One-year-follow-up including standard dynamic pedography is planned. The following scores are used: American Orthopaedic Foot and Ankle Society (AOFAS), Visual-Analogue-Scale Foot and Ankle (VAS FA), Short-Form 36 (SF36, standardized to 100-point-maximum). Intraoperative consequences after the use of intraoperative pedography were recorded.

Results: Validation Step 1: 30 individuals were included (age, 26.1±8.6 years; gender, male: female = 24: 6). Step 2: 30 individuals were included (age, 55.3±30.3 years; gender, male: female = 24: 6). No significant differences between all measurements of step 1 and 2 were found for step 1 and 2 without the dynamic platform measurements of step 1.

Clinical use: 16 patients were included until January 31, 2006 (ankle correction arthrodesis, n=2; subtalar joint correction arthrodesis, n=4; arthrodesis midfoot, n=4, correction forefoot, 4; Lisfrcan-fracture-dislocation, n=2). 9 patients were randomized for the use of intraoperative pedography. The mean preoperative scores were: AOFAS: 49.6±23.7; VAS FA: 42.2±13.1; SF36: 48.1±23.2. The mean interruption of operative procedure for the intraoperative pedography was 359±34 seconds. In 4/9 cases changes were made after intraoperative pedography during the same operative procedure (correction modified, n=3; screw tightened, n=1). The follow-up has not been completed so far.

Conclusion: Since no statistical significant differences were found between the measurements of intraoperative pedography in anaesthesized individuals and the standard static pedography, the introduced method can be considered to be valid for intraoperative static pedography.

During the clinical use, in 44% of the cases a modification of the surgical correction were made after intraoperative pedography in the same surgical procedure.

The problem: A few operative procedures were used for radiolunate fusion for stabilization of the rheumatoid wrist. Because of minor stability of these fixations, cast immobilization of the wrist is necessary for several weeks, which may lead to a limited wrist motion through the scar of the joint capsule. Non-union and loosening of the osteosynthesis material were described for all of these procedures.

Method: a three dimensional bended mini-titanium-T-plate (produced by Martin/Germany) with an additional oblique screw withstands the forces acting on the fixed lunate, as there are palmar flexion, dorsal extension, radial and ulnar abduction, rotation along the longitudinal axis, palmar and ulnar shift. The high primary stability results from a three point fixation of the lunate an the form of the plate. Because of this very stable fixation, early exercise of the wrist is allowed from the third day after operation. After reduction of the soft tissue swelling the palmar cast is replaced by a ready-made wrist splint, which can be removed by the patient for exercise of the wrist three times a day.

Results: 20 radiolunate fusions have been performed by this new technique since the year 2000. Bone healing was achieved in all. Cast immobilization after surgery was reduced from a period of 3 to 8 weeks for the first 9 wrists to the period of soft tissue swelling (6 to 10 days) for the 11 wrists operated at least. Through early exercise of extension and flexion of the wrist, the average range of wrist extension and flexion rose from 60 degrees in the first group to 70 degrees in the latter.

Conclusion: The radiolunate fusion with a three dimensional bended minititanium-T-plate and an oblique screw neutralizes the forces on the lunate. Because of this, early exercise of the wrist is possible to minimize limitation of the wrist motion through the shrinking scar of the joint capsule. Furthermore the light wrist splint is very comfortable to the patient, because it gives low stress on the other joints and can be removed easily for exercise and skin care.