Shoulder function after helical long PHILOS plate.

BACKGROUND: In order to minimize the risk of damaging the radial nerve while using a long PHILOS plate for proximal humerus fractures, recent studies have proposed twisting the plate in a helical form. This implies a modified surgical approach being yet unclear whether it leads to different middle to long-term shoulder function. This study compares the one-year shoulder functional outcomes of both techniques (helical vs. control). METHODS: In this retrospective comparative study, we analyzed 30 patients that fit the inclusion criteria, being 14 treated with a helical plate and 16 with a conventional straight long PHILOS plate. The primary endpoint was the normalized constant score after a minimum follow up of one year. RESULTS: Both groups had a good one-year shoulder function, and no significant difference between the normalized constant scores was seen. There was no significant difference in the surgical complications as well. CONCLUSION: Opting for a helical long PHILOS plate in order to avoid radial nerve damage provided a safe treatment with similarly good one-year shoulder function compared to straight PHILOS plates. LEVEL OF EVIDENCE: Level 3, Retrospective Cohort Study.

Comparing iatrogenic radial nerve lesions in humeral shaft fractures treated with helical or straight PHILOS plates: a 10-year retrospective cohort study of 62 cases.

BACKGROUND: Humerus shaft fractures are common and often treated surgically with a proximal humerus internal locking system like the long PHILOS® plate. Due to its close anatomical proximity to the humerus, the radial nerve is particularly susceptible to traumatic and iatrogenic damage. The iatrogenic radial nerve damage associated with internal locking systems is described in about 7% of the cases. In order to avoid this lesion, helical plates have been suggested since 1999. This technique continues to not being used as standard as there is still a clear lack of evidence. This study aimed to understand if twisting a long PHILOS plate can reduce the rate of iatrogenic radial nerve damage in humerus shaft fractures. METHODS: In this 10-year retrospective comparative study, patients with primary traumatic proximal humerus shaft fracture treated with a straight or twisted helical PHILOS® plate were analyzed and compared. Among the 62 patients meeting the inclusion criteria between 2008 and 2018, 33 received a conventional straight plate, while 29 were treated with a helical plate. The primary endpoint was iatrogenic radial nerve damage immediately after surgery with a follow-up of at least 3 months. RESULTS: No case of radial nerve damage was reported in the helical group. In the control group, iatrogenic radial nerve damage occurred in two cases (6%), which was not statistically significant when comparing both groups (p = 0.18). CONCLUSION: Manually twisting long PHILOS® plates is a safe procedure to avoid radial nerve lesion in humerus shaft fractures. Even though the group size did not allow a statistically relevant difference, we underline that only the helical group showed no iatrogenic radial lesion. This technique deserves further attention. LEVEL OF EVIDENCE: Level 3, retrospective cohort study.

Soluble gp130 prevents interleukin-6 and interleukin-11 cluster signaling but not intracellular autocrine responses.

Interleukin-6 (IL-6) is a proinflammatory cytokine of the IL-6 family, members of which signal through a complex of a cytokine-specific receptor and the signal-transducing subunit gp130. The interaction of IL-6 with the membrane-bound IL-6 receptor (IL-6R) and gp130 stimulates "classic signaling," whereas the binding of IL-6 and a soluble version of the IL-6R to gp130 stimulates "trans-signaling." Alternatively, "cluster signaling" occurs when membrane-bound IL-6:IL-6R complexes on transmitter cells activate gp130 receptors on neighboring receiver cells. The soluble form of gp130 (sgp130) is a selective trans-signaling inhibitor, but it does not affect classic signaling. We demonstrated that the interaction of soluble gp130 with natural and synthetic membrane-bound IL-6:IL-6R complexes inhibited IL-6 cluster signaling. Similarly, IL-11 cluster signaling through the IL-11R to gp130 was also inhibited by soluble gp130. However, autocrine classic and trans-signaling was not inhibited by extracellular inhibitors such as sgp130 or gp130 antibodies. Together, our results suggest that autocrine IL-6 signaling may occur intracellularly.