Is DISI Deformity Related to Presence of a Medial Lunate Facet in Patients with Scapholunate Dissociation?

Background Lunate morphology has been suggested to influence carpal kinematics. Purpose We investigate a possible relation between presence of a medial lunate facet and dorsal intercalated segment instability (DISI) of the wrist in patients with a scapholunate (SL) dissociation. Methods We retrospectively reviewed patients diagnosed with SL dissociation between 2000 and 2017. Lunate morphology was categorized based on radiographs and magnetic resonance imaging (MRI), as type I or II according to Viegas and Galley. DISI was defined as radiolunate angle > 15 degrees and SL instability as SL angle > 60 degrees. SL distance > 3 mm was considered as widening and carpal height ratio < 0.5 was considered as carpal collapse. We used descriptive statistics to report on SL instability and DISI in patients with Viegas type I and type II lunates. We calculated kappa to determine agreement between radiographs and MRI and to determine inter- and intraobserver agreement. Results Of 119 patient files, 79 wrists met the inclusion criteria of which 25 were type I lunates and 54 type II. Similar spreading of the data of both groups was found regarding DISI, SL instability, and SL widening based on radiographic classification of the lunate, even after adding MRI findings. In the presence of carpal collapse, capitate-to-triquetrum distance was higher. We found a substantial inter- and intraobserver agreement for lunate classification. Conclusion Our results suggest a similar prevalence of DISI deformity or enlarged SL angle in patients with type I or II lunate in presence of SL dissociation. The Viegas classification is a reliable and reproducible classification system. Level of evidence This is a Level III, cross-sectional study design.

Metal ion levels in ceramic-on-ceramic THR with cobalt-chrome modular necks: analysis of cobalt and chromium serum levels in 23 healthy hip patients.

BACKGROUND: Modular necks in total hip replacement (THR) can be a source of metal ion release. METHODS: We measured the level of cobalt (Co) and chromium (Cr) ions in the serum of 23 healthy volunteers with a well-functioning ceramic-on-ceramic THR of a particular design, containing a cobalt-chrome (Co-Cr) stem and a Co-Cr modular neck. RESULTS: Average Co in serum was 1,71 µg/l; median Co was 1.50 µg/l. No patient had Co levels higher than 3.70 µg/l. Average Cr level was 0.49 µg/l; in all but one patient Cr was below the detection limit (<0.50 µg/l). Co was higher for varus necks compared to all other subtypes: 2.14 µg/l vs 1.58 µg/l (p<0.05). The same system with Titanium modular necks shows lower Co serum levels: 1.26 µg/l (p<0.01 ). In conclusion, the hybrid THR Profemur Xm® - Procotyle L® with a Co-Cr modular neck on a Co-Cr stem design shows very low Cr ion serum levels in a randomly selected group of well-functioning hip patients. CONCLUSIONS: Co ion serum levels are low, but significantly higher for 8° varus necks, and Co levels are significantly higher than values of this system with a Titanium modular neck.

Does the "three-ligament tenodesis" procedure restore carpal architecture in static chronic scapholunate dissociation?

The effect of the three-ligament tenodesis on the scapholunate angle and scapholunate gap was studied. A comparison was made between these angles preoperatively and postoperatively in 12 patients. There was a significant decrease in the scapholunate angle from 77 to 68 degrees, and the scapholunate gap was reduced from 4.25 mm to 3.29 mm. We also studied the correlation between scapholunate angle and scapholunate gap postoperatively in a cohort of 25 patients and found a significant correlation. This suggests that the principle of the procedure is correct, but the aims are not fully achieved, and that the procedure has a similar effect on SL gap and SL angle.

Failures of the three-ligament tenodesis for chronic static scapholunate dissociation are due to insufficient reduction.

We retrospectively reviewed 13 patients who had successfully undergone three-ligament tenodesis for scapholunate instability, and compared the radiological outcome with 14 failed cases. The scapholunate angle in the failed group increased from 73 degrees to 81 degrees with a scapholunate gap of 532 mm, compared to a decrease in the successful group from 76 degrees to 66 degrees with a scapholunate gap of 2.94 mm. Postoperative radiographs may thus have a prognostic value and can also be used if confronted with a patient with persisting symptoms after operation. Salvage procedures may offer a better solution when tenodesis has failed and reduction is insufficient on radiographs, and we believe that redo operations are not indicated, when the initial reduction already failed.

Delayed migration of a metal suture anchor into the glenohumeral joint.

Intra-articular migration is a known complication of poorly placed metallic suture anchors in rotator cuff repair and labral reconstruction. We report a case of intra-articular migration of a metallic suture anchor seven years after open labral reconstruction. Despite the fact that the patient remained asymptomatic for seven years, presence of an extra-osseous anchor was already noted postoperatively. In an era where the use of suture anchors has become common practice, surgeons should always be aware of possible anchor migration, especially when patients complain of sudden sharp pain, persistent pain, a catching sensation and loss of mobility.