The wrist and scapholunate ligament dysfunction: Dealing with biomechanics, diagnosis, and treatment

This thesis contains the results of studies performed to obtain more insight in biomechanics, diagnosis and treatment for scapholunate interosseous ligament (SLIL) injuries.

PART I

In part I, the wrist biomechanics after two common surgical procedures for scapholunate dysfunction were studied.
Chapter 2 reported wrist biomechanics after capsulodesis. In maximal flexion, the dorsal intercarpal reconstruction showed a mean elongation of 0.8 mm. No failure of the dorsal intercarpal reconstruction was observed. The dorsal intercarpal complex (DIC) showed an elongation of 3.9 mm. when the wrist was flexed maximally. In four arms sutures connecting the dorsal intercarpal complex to the surrounding tissue loosened between 55 and 60 degrees.
Chapter 3 examined elongation in relation to flexion, and type of failure after a 3-Ligament tenodesis (3LT). At 80 flexion, mean elongation of the flexor carpi radialis (FCR) tendon slip was 0.96  0.38 mm. Mean elongation of the DIC was 3.75  0.91 mm. at 80 flexion. Relative elongation of the FCR tendon slip was 4.1% and 33.4% of the DIC. In two tests (4%), sutures loosened at the proximal side of the DIC after 30 flexion. Ruptures of the radiotriquetral ligament, pull-outs of the bone anchor or FCR tendon ruptures were not observed.
The experiments suggested that the capsulodesis technique creates a reconstruction which can withstand 55 degrees flexion, and the 3-LT reconstruction tolerates up to 30 degrees without failure.

PART II

Given the limited reliability and accuracy of imaging, many surgeons consider wrist arthroscopy to be important for the diagnosis of SLIL pathology.
In Chapter 4, the influence of diagnostic arthroscopy on treatment recommendations and reliability of the arthroscopic classification for SLIL pathology was studied in a survey-based experiment. Seventy-seven surgeons evaluated scenarios of patients with wrist pain and a variation in symptoms, scaphoid shift test, time since onset of symptoms, and MRI appearance of the SLIL. Participants were randomized to view or not to view diagnostic wrist arthroscopy, and all surgeons viewing arthroscopic videos were asked to grade the SLIL pathology. The interobserver reliability of grading SLIL injury severity was none to slight (κ=0.18; 95% CI, 0.11 – 0.26). Diagnostic arthroscopy led to more recommendations for surgery (OR 6.9; 95% CI, 2.8 – 18; P<0.001), and more invasive surgery (RR 2.4; 95% CI, 1.3 – 4.2; P=0.004).
In Chapter 5, the addition of midcarpal arthroscopy versus radiocarpal arthroscopy alone was evaluated. Fourteen consecutive videos of diagnostic radiocarpal and midcarpal wrist arthroscopy for suspected SLIL pathology were selected. Sixty international surgeons were asked to grade the severity of SLIL pathology and to recommend surgical or nonsurgical treatment. The interobserver agreement for the Geissler classification was slight/fair for observers who reviewed midcarpal and radiocarpal videos (κ=0.21 [fair]; 95% CI, 0.10 – 0.32) and none to slight for those who viewed radiocarpal videos only (κ=0.18 [slight]; 95% CI, 0.076 – 0.28). Viewing midcarpal videos was associated with higher pathology grades, more recommendations for surgery, and a preference for tenodesis over scapholunate ligament repair.
In Chapter 6, online information for patients about SLIL dysfunction was assessed. Online information quality was measured using DISCERN, readability was measured using Simple Measure of Gobbledygook (SMOG; reflects how many years of education a person needs to understand a text), and present dominant tones in text were measured using the IBM Watson Tone Analyzer. The online information regarding SLIL dysfunction was of generally low quality, with limited readability (SMOG: 10 ± 1.9). None of the websites addressing SL dysfunction met standards for readability with fewer than 6 years of education. A dominant tone of fear correlated with difficult to read texts (r=1.0, P=0.015), a dominant tentative tone (r=-0.44, P=0.0034) with easier texts.

PART III

In Chapter 7, of this thesis, a systematic review provided an overview of postoperative immobilization protocols for surgically treated scapholunate ligament injuries and reported their impact on patient-reported outcomes. Fifteen studies involving 533 patients were included. Most patients (82%) underwent tenodesis, 18% underwent capsulodesis. The executed techniques varied widely. Immobilization varied from 2 to 8 weeks. No differences were observed between short (≤6 weeks) and long (>6 weeks) immobilization in terms of PROMs, pain, range of motion, grip strength or complications.
In Chapter 8, a multicenter cohort study was performed to investigate whether early active motion was noninferior to late active motion after 3-ligament tenodesis.
This study compared a late active motion protocol (immobilization for 10-16 days, starting wrist therapy in week 5-6) with an early active motion protocol (immobilization for 3-5 days, starting wrist therapy in week 2). A total 108 of patients were included. Patient-Reported Wrist/Hand Evaluation (PRWHE, P=0.35) and pain during physical load (P=0.85) following an early active motion protocol were non-inferior compared to a late active motion protocol. Furthermore, it did not lead to more complications (P=0.54), differences in range of motion, grip strength (P=0.65) or less satisfaction with the treatment result (P=0.36). Earlier return to activities was not observed.
In Chapter 9, a prospective multicenter cohort study was performed to examine whether patients with a distal radius fracture and distal radioulnar joint (DRUJ) instability or scapholunate dissociation (SLD) have different reported outcome measures after 1 year. The primary outcome was the PRWHE at 6 and 12 months after surgery for the distal radius fracture. Out of 62 patients, 58% had intraoperative distal radioulnar joint instability and 27% scapholunate dissociation. No significant differences were found in patient-reported scores at follow-up between patients with stable and unstable distal radioulnar joints, nor between patients with and without scapholunate dissociation. Sixty-three percent of patients with an unstable distal radioulnar joint during surgery were stable when tested again after 6 months.