Early aseptic loosening of a press-fit radial head prosthesis - A case series of 6 patients.

OBJECTIVE: Radial head arthroplasty (RHA) is the principal treatment option for comminuted radial head (RH) fractures. Here, we present six cases of failed RHA using a modular monopolar press-fit RHA that was subsequently withdrawn from the market because it was associated with a high incidence of loosening. METHODS: We retrospectively collected data from six patients who had received Radial Head Prothesis SystemTM at our centre between July 2015 and June 2016. The average follow-up was 40 months. RESULTS: Aseptic loosening of the stem affected five (83%) of the six RHA. Four of these were symptomatic and RHA removal was performed. For these patients, the pain subsided and their elbow range of motion (ROM) improved. CONCLUSION: While the ideal design for an RHA is still debatable, RHA is an efficient treatment option that restores elbow stability and function after a comminuted RH fracture. Importantly, removal of the prosthesis is an effective remedy following RHA associated elbow pain and decreased ROM.

The incidence of hip dislocation after posterior approach primary total hip arthroplasty: comparison of two different posterior repair techniques.

INTRODUCTION: Total hip arthroplasty (THA) remains one of the most successful orthopedic surgical procedures. The posterior approach is associated with a higher incidence of post-operative dislocations than others. Adequate posterior soft tissue repair techniques, including capsulorrhaphy and transosseous bone sutures in the greater trochanter effectively reduce the dislocation rate. Post-operative "posterior hip precautions" were historically believed to reduce dislocation risks, although not clearly proven. The first protocol consists of capsulorrhaphy with the prescription of post-operative posterior hip precautions (TT) and the second, transosseous bone sutures without precautions (TB). This study aims to determine the optimal protocol to decrease the dislocation rate following posterior approach primary THA. MATERIALS AND METHODS: A 10-year retrospective case-control chart review analyzed demographic, pre-, intra-, and post-surgical parameters. Primary outcomes were the difference in dislocation and revision surgery rates between protocols. Secondary outcomes included the incidence of recurrent dislocations and the identification of predictors of dislocation. RESULTS: 2,242 THAs were reviewed and 26 (1.2%) resulted in dislocation. Increased age (p = 0.04) ASA score (p = 0.03) and larger acetabular cup size (p < 0.001) were associated with heightened risk. Tendon to tendon (TT) repair saw a 1.62% dislocation rate versus 0.98% for tendon-to-bone (TB) repair, although statistically insignificant (p = 0.2). Transosseous repair resulted in recurrent dislocations for 8/16 (50%) patients compared to 6/10 (60%) in the suture group (p ≤ 0.001). No significance was found for prescription of posterior hip precautions. CONCLUSIONS: To our knowledge, this is the first study to perform a direct comparison of TT repair with posterior precautions to TB repair without posterior precautions. Similarity in dislocation rate, decreased recurrent events and the alleviated patient burden from precautions leads the authors to recommend the TB repair without precautions for a successful THA.

Does candidate for plate fixation selection improve the functional outcome after midshaft clavicle fracture? A systematic review of 1348 patients.

INTRODUCTION: The hypothesis of this study was that patient selection for midshaft clavicle fracture (open reduction internal fixation with plate versus conservative) would give better functional outcome than random treatment allocation. METHODS: We performed a systematic literature search for primary studies providing functional score and non-union rate after conservative or surgical management of midshaft clavicle fractures. Six randomized controlled trial and 19 non-randomized controlled trial studies encompassing a total of 1348 patients were included. RESULTS: Patients treated with surgical management were found to have statistically superior Constant scores in non-randomized controlled trials than in randomized controlled trials (94.76 ± 6.4 versus 92.49 ± 6.2; p < 0.0001). For conservative treatment, randomized controlled trials were found to have significantly better functional outcome. The prevalence of non-union (6.1%) did not show significant statistical difference between non-randomized controlled trial and randomized controlled trial studies. The functional outcome after surgical management was significantly higher than after conservative management in both randomized controlled trial and non-randomized controlled trial groups. The non-union rate after surgery (1.1% for both non-randomized controlled trial and randomized controlled trial) was significantly lower than following conservative treatment (9.9% non-randomized controlled trial versus 15.1% randomized controlled trial). DISCUSSION: This review shows that patient selection for surgery may influence functional outcome after midshaft clavicle fracture. Our results also confirm that plate fixation provides better functional outcome and lower non-union rate.

Phenomenologically distinct psychotomimetic effects of ketamine are associated with cerebral blood flow changes in functionally relevant cerebral foci: a continuous arterial spin labelling study.

RATIONALE: The N-methyl-D-aspartate (NMDA) receptor antagonist ketamine provides a pragmatic approach to address the link between glutamate-mediated changes in brain function and psychosis-like experiences. Most studies using PET or BOLD fMRI have assessed these symptoms broadly, which may limit inference about specific mechanisms. OBJECTIVES: The objective of this study is to identify the cerebral blood flow (CBF) correlates of ketamine-induced psychopathology, focusing on individual psychotomimetic symptom dimensions, which may have separable neurobiological substrates. METHODS: We measured validated psychotomimetic symptom factors following intravenous ketamine administration in 23 healthy male volunteers (10 given a lower dose and 13 a higher dose) and correlated ketamine-induced changes in symptoms with regional changes in CBF, measured non-invasively using arterial spin labelling (ASL). RESULTS: The main effect of ketamine paralleled previous studies, with increases in CBF in anterior and subgenual cingulate cortex and decreases in superior and medial temporal cortex. Subjective effects were greater in the high-dose group. For this group, ketamine-induced anhedonia inversely related to orbitofrontal cortex CBF changes and cognitive disorganisation was positively correlated with CBF changes in posterior thalamus and the left inferior and middle temporal gyrus. Perceptual distortion was correlated with different regional CBF changes in the low- and high-dose groups. CONCLUSIONS: Here, we provide evidence for the sensitivity of ASL to the effects of ketamine and the strength of subjective experience, suggesting plausible neural mechanisms for ketamine-induced anhedonia and cognitive disorganisation.