The acromioclavicular (AC) joint dislocation is a major reason for shoulder instability. Different concepts of treatment and surgical methods are described in the literature. Thus, the purpose of this study was to present our data of long-term follow-up of patients having undergone treatment of acromioclavicular (AC) joint dislocation using the Bosworth Screw with additional K-wiring. This study was conducted as a retrospective single centre data analysis. All patients treated operatively for AC joint dislocation with a Bosworth screw and additional K-wire fixation at our Department were asked to participate in this study. The study population consisted of 22 patients, 20 male and 2 female, with a mean age of 40 years ±15.6 years. Three grade-II lesions, 13 grade-III lesions, four grade-IV lesions and two grade-V lesions according to the Rockwood classification were found. The overall mean clinical outcome at the latest follow up was: Constant 95, DASH 6.4, ASES 94.6, SST 99.02, UCLA 33.1, ACJI 91.82 and VAS 0.29 – representing a good-to-excellent long-term outcome in all patients after at least 2 years follow-up (range; 2 - 19 years). Overall, 19 patients (86%) reported to be very satisfied with the achieved result, 15 patients (68%) reported to be able to participate in every sports activity and 16 patients (73%) reported to be able to perform their daily work without limitations. Overall, complications occurred in three patients (14%). Only one patient remained unsatisfied with the achieved result. Summarizing, our reported results showed that surgical fixation of acute AC joint dislocation with a Bosworth screw and additional K-wire fixation leads to good-to-excellent functional outcome and highly satisfactory results in the majority of patients. Despite its complications, in accordance with our results, Bosworth screw fixation with additional K-wiring in AC joint dislocation represents an adequate surgical procedure. Level of Evidence: Level IV, retrospective study.

The postoperative course after arthroscopic superior labrum anterior to posterior (SLAP) repair using suture anchors is accompanied by a prolonged period of pain, which might be caused by constriction of nerve fibres. The purpose was to histologically investigate the distribution of neurofilament in the superior labrum and the long head of the biceps tendon (LHBT), i.e. the location of type II SLAP lesions. Ten LHBTs including the superior labrum were dissected from fresh human specimen and immunohistochemically stained against neurofilament (NF). All slides were scanned at high resolution and converted into tagged image file format, and regions of interest (ROIs) were defined as follows: ROI I—superior labrum anterior to the LHBT origin, ROI II—mid-portion of the superior labrum at the origin of the LHBT, ROI III—superior labrum posterior to the LHBT origin and ROI IV—the most proximal part of the LHBT before its attachment to the superior labrum. The entire images were automatically segmented according to the defined ROIs and measured using a programmed algorithm specifically created for this purpose. The NF-positive cells were counted, and their total size and the area of other tissue were measured separately for the different ROIs. Distribution of NF-positive cells in absolute numbers revealed a clear but insignificantly higher amount in favour of ROI I, representing the superior labrum anterior to the LHBT origin. Setting ROI I at 100%, a significant difference could be seen compared to ROI III, representing the superior labrum posterior to the LHBT origin (ROI I vs. ROI III with a p value < 0.05). Summarizing, the density of neurofilament is inhomogeneously distributed throughout the superior labrum with the highest number of neurofilament in the anterior superior labrum. Thus, suture placement in type II SLAP repair could play an important role for the postoperative pain-related outcome.