Chronische scafolunaire letsels - Kinematische analyse en behandelingsopties

SUMMARY Normal hand function is a prerequisite for most daily activities and requires a stable motion pattern in the wrist. Despite the lack of tendon attachments to 7 of the 8 carpal bones, the wrist can provide a stable range of motion using coordinated muscle activation cooperating with a complex ligamentous configuration. Ligament lesions can disrupt this fragile joint and start a cascade of altered motion, altered load distribution and ultimately degenerative changes in the wrist. A lesion of the scapholunate ligament, the most common carpal ligament injury, challenges the secondary stabilizers of the SL interval and changes wrist kinematics. A spectrum of SL instability commences, possibly evolving into a static carpal deformity referred to as DISI (dorsal intercalated segment instability), causing a predictable pattern of wrist degeneration, starting at the radial styloid. Because diagnosis is often delayed, most frequently, SL complex lesions need to be treated with a reconstructive procedure. Several procedures are described in literature, with the three-ligament tenodesis and modified Brunelli tenodesis (2 similar techniques) being the best described procedure. In a first part of this project, we described the results of this current practice. We performed a systematic review, describing the results of both techniques and focusing on long-term outcome. Using 15 reports for this review, we found a wide variety in surgical technique and postoperative treatment, making it hard to compare results. Considering motion, postoperative decrease in flexion/extension was more pronounced than radioulnar deviation loss, when combining al procedures (MBT, 3LT, long-and short-term outcome) to one group. Average pain scores decreased from severe pain before to moderate pain after surgery. Return to work rate varied widely between both procedures and required work modifications up to 20% in both patient groups. A high complication rate was seen (up to 9%). Although we noticed a high incidence of radiographic signs of degeneration (up to 25% after 5 years), the need for salvage surgery was lower, so not every SLAC wrist requires aggressive treatment. The long-term results of UZ Leuven were described in a separate report, following 50 patients for 9 years. In this patient cohorts, 30% required salvage surgery. We noticed inferior radiographic parameters in the short-term in this group of 'failed' patients. Only 32 % of the other patients were available for review and in this group, low pain scores, high satisfaction scores and good functional scores were seen. Radiographic evaluation showed a significant deterioration in the long-term, not correlated to function. Progression to wrist degeneration was seen in 63% of these successful cases and an overall complication rate of 10% was noted. The question remains whether these reconstructive techniques, with a non-negligibly high complication rate can truly influence the natural evolution of a lesion of the SL complex. Lunate morphology has been suggested to influence carpal kinematics. A retrospective review was performed to investigate possible relation between the presence of a medial lunate facet and DISI deformity of the wrist in patients with SL dissociation. Lunate morphology was categorized using Viegas classification on radiographs and MRI when available. The Viegas classification system was found reliable and reproducible, based on a repeated-measures analysis for 2 observers. When comparing groups of type I and type II lunate, we found similar spread of radiographic parameters describing SL instability (SL angle, RL angle, SL distance and carpal height ratio). We concluded that lunate type does not have a large impact on the development of DISI deformity although we acknowledge this project was limited by its retrospective nature and sample of convenience. In the next part of this project, we focused on the early diagnosis of SL complex lesions, because early treatment might improve long-term results. Even though a SL ligament lesion is highly prevalent in wrist trauma, the diagnosis is often delayed. Several static imaging modalities (stress radiographs, CT and MRI scan with or without arthrography) can help diagnosing these lesions, but diagnosis of (pre)dynamic lesions on static images and interpretation of contrast flow through microperforations remains challenging. Wrist arthroscopy is the golden standard in diagnosis of carpal ligament injuries, but is invasive, expensive and demands experience. A quantitative diagnostic tool is needed. More recently, 4D CT has emerged as a novel CT-based imaging modality, combining a good temporal and spatial resolution, allowing to evaluate a wrist in motion. Several 4D CT measures have been suggested for evaluation of SL (in)stability, but validation of these techniques is lacking. We presented a technique to measure SL distance based on 4D CT acquired images and evaluated our technique in a repeated-measures study, using data of 7 patients. We found the proposed technique a reliable and reproducible measurement for SL distance. After validating this measurement technique, it was used in a pilot study including patients suspected of a SL lesion. This pilot was designed to evaluate the clinical application/feasibility of 4D CT evaluation of patients and to compare dynamic SL distance of the impaired and healthy wrist. We pointed out to several possibilities where future improvement of recording, as well as data processing can be implemented. The small sample size of this pilot did not allow to draw hard conclusions, but we did find the RUD motion contained differences between healthy and impaired side in all cases for range in SL distance (for dorsal SL interval) as well as relative elongation/shortening when compared to the neutral wrist position (for dorsal, proximal and volar interval). Based on a sample size calculation combined with clinical feasibility, an expansion of this patient group to 35 patients is suggested. In conclusion the results of this new diagnostic technique are promising but work still need to be done before this can be implemented in daily clinical practice. Searching to improve the results of the chronic SL reconstruction, a new technique, connecting the scaphoid and lunate using a central and dorsal axis was explored in a biomechanical cadaver study in the next chapter. This technique respects the biomechanical importance of the dorsal part of the SL ligament and provides a double link between scaphoid and lunate, enhancing stability. Using a wrist motion simulator and 4D CT analysis, an evaluation of the dynamic SL distance (similar as in the previous chapter) of 6 cadaveric wrist specimens was performed. Each wrist was evaluated in its normal state, after creation of a complete SL dissociation and after reconstruction. We found this technique provides a good reconstruction of the dynamic SLD when comparing the 3 different ligamentous states of the wrists. We were able to address widening of the SL interval on both the dorsal and palmar side. Concerns arise however about the differences in elasticity between the natural SL complex and reconstruction, possibly enhancing adverse results. In the last part of this project, we focused on those cases with a long existing SL ligament lesion, that developed a SLAC wrist (scapho-lunate advanced collapse). In case of degeneration, a reconstructive procedure is no longer relevant and only salvage options, most frequently proximal row carpectomy and four-corner fusion can be used. We questioned if one of these techniques is superior. To answer this question, we performed a systematic review of 84 papers reporting on the results of PRC and FCA for posttraumatic wrist degeneration. A mean follow-up of 9 years and 7 years respectively was noted. Although mean flexion-extension arc was slightly higher after PRC, this was not a relevant difference from a clinical point of view. Grip strength was comparable after both procedures. Up to 42% of cases developed wrist degeneration after PRC, independent of the shape of the capitate, but only 4% of the total PRC-group needed conversion to wrist fusion. Complication rate in the FCA-group was higher, with 5% need for revision of the partial fusion and 5% conversion to complete wrist fusion. We prefer PRC because of the lower complication rate but suggest FCA in the younger population because of the rate of wrist degeneration after PRC. In conclusion, this PhD thesis addresses different aspects of scapholunate complex lesions. The results of current treatment of chronic SL lesions with or without degeneration are resumed. Further steps to improve current diagnostic capacity were explored and a biomechanical analysis of a new reconstructive technique was included. Several possible points of improvement within these different aspects were suggested and will be explored in the continuation of this research.