Potential neurotoxicity of titanium implants: Prospective, in-vivo and in-vitro study.

Titanium dioxide (TiO2) is a frequently used biomaterial, particularly in orthopedic and dental implants, and it is considered an inert and benign compound. This has resulted in toxicological scrutiny for TiO2 in the past decade, with numerus studies showing potential pathologic downstream effects. Herein we describe case report of a 77-year-old male with subacute CNS dysfunction, secondary to breakdown of a titanium-based carotid stent and leading to blood levels 1000 times higher (3 ppm) than the reported normal. We prospectively collected tissues adjacent to orthopedic implants and found a positive correlation between titanium concentration and time of implant in the body (r = 0.67, p < 0.02). Rats bearing titanium implants or intravascularly treated with TiO2 nanoparticles (TiNP) exhibited memory impairments. A human blood-brain barrier (BBB) in-vitro model exposed to TiNP showed paracellular leakiness, which was corroborated in-vivo with the decrease of key BBB transcripts in isolated blood vessels from hippocampi harvested from TiNP-treated mice. Titanium particles rapidly internalized into brain-like endothelial cells via caveolae-mediated endocytosis and macropinocytosis and induced pro-inflammatory reaction with increased expression of pro-inflammatory genes and proteins. Immune reaction was mediated partially by IL-1R and IL-6. In summary, we show that high levels of titanium accumulate in humans adjacent to orthopedic implants, and our in-vivo and in-vitro studies suggest it may be neurotoxic.

A Multicenter Retrospective Study With a Minimum 5-Year Follow-up Comparing Arthroscopic Bankart Repair and the Latarjet Procedure.

BACKGROUND: Arthroscopic Bankart repair (ABR) and the Latarjet procedure are surgical techniques commonly used to treat anterior shoulder instability. There is no consensus among shoulder surgeons regarding the indications for choosing one over the other. PURPOSE: To compare the results of the Latarjet procedure with those of ABR for the treatment of anterior shoulder instability. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data on all patients who were treated surgically for recurrent anterior shoulder instability between 2006 and 2011 were retrospectively collected at 4 medical centers. The minimum follow-up was 5 years. Data were retrieved from medical charts, and patients were interviewed to assess their level of satisfaction (range, 0-100), functional outcomes (using the American Shoulder and Elbow Surgeons shoulder score; the Subjective Shoulder Value; and the Disabilities of the Arm, Shoulder and Hand score), and quality of life (using the 12-Item Short Form Health Survey [SF-12]). Information on return to sports activities and postoperative level of activity compared with that of the preinjury state, complications, reoperations, and recurrent instability were recorded and evaluated. RESULTS: A total of 242 patients were included. The Latarjet procedure was performed in 27 shoulders, and ABR was performed in 215 shoulders. Patients in the ABR group had significantly higher rates of redislocation (18.5%; P = .05) and subluxation (21.4%; P = .43) but a lower rate of self-reported apprehension (43.0%; P = .05) compared with patients in the Latarjet group (3.7%, 14.8%, and 63.0%, respectively). There were 5 patients in the ABR group who underwent reoperation with the Latarjet procedure because of recurrent instability. The functional scores in the Latarjet group were better than those in the ABR group. The SF-12 physical score was significantly better in the Latarjet group than in the ABR group (98.1 vs 93.9, respectively; P = .01). Patient satisfaction and subjective scores were similar in both groups. CONCLUSION: These results support recently published data on the Latarjet procedure that showed its superiority over ABR in midterm stability (dislocations or subluxations). The contribution of self-reported apprehension to the broad definition of stability is not clear, and apprehension rates were not correlated with satisfaction scores or the recurrence of dislocation or subluxation.

Sub-acromial balloon spacer for irreparable rotator cuff tears: Is it an appropriate salvage procedure?

INTRODUCTION: Irreparable rotator cuff tear (RCT) presents a difficult treatment challenge for the orthopaedic surgeon. Many treatment strategies with varying degrees of success have been performed over the years. One of the suggested surgical treatment options is the use of a biodegradable sub-acromial balloon spacer. METHODS: A retrospective study of patients treated with sub-acromial balloon spacer between the years 2011 and 2016 was conducted. Mean follow-up time was 14.4 months. Patient charts were reviewed to evaluate the early clinical results and complications of sub-acromial spacer for irreparable RCTs. RESULTS: The study cohort included 24 shoulders in 22 patients. The average postoperative Disability of the Arm, Shoulder and Hand score was 62.4. The average preoperative University of California at Los-Angeles Shoulder score was 10.9 and improved to 15.9 ( p = 0.001). Forty-six per cent of patients were satisfied with their clinical postoperative outcome. We found moderate-strong positive correlation ( r = 0.64) between preoperative range of motion (ROM) and general satisfaction. None of the postoperative radiographs showed an improvement regarding the proximal migration of the humeral head. In total, four (16.7%) patients experienced postoperative complications, and two (8.3%) patients required an additional surgery as a consequence of a postoperative complication. CONCLUSION: Our results show unsatisfactory improvement in patients with irreparable RCT treated with the sub-acromial balloon spacer. Careful patient selection with attention to preoperative ROM should be considered. LEVEL OF EVIDENCE: Therapeutic level IV.

Rotator cuff tears: correlation between geometric tear patterns on MRI and arthroscopy and pre- and postoperative clinical findings.

BACKGROUND: Magnetic resonance imaging (MRI) is considered to be the best non-invasive procedure for the evaluation of rotator cuff (RC) tendon tears. Burkhart's classification is a geometric classification of full-thickness RC tears on MRI. PURPOSE: To correlate MRI and arthroscopic geometric full-thickness RC tears according to the Burkhart's classification with pre- and postoperative clinical findings. MATERIAL AND METHODS: Patients who underwent arthroscopic RC repair between 2006 and 2010 were retrospectively evaluated. Preoperative MRI and arthroscopic surgical reports were reviewed for tear geometry (Burkhart's) by three (1 radiologist, 2 surgeons) and two (surgeons) readers. MRIs were also evaluated for tear size and change of tear size in successive sagittal sections and for muscle mass and fatty infiltration. Clinical examinations were performed preoperatively and at least 12 months afterwards. Postoperative function questionnaires were filled in by the patients. RESULTS: Forty-six patients (35 men, 11 women; mean age, 57 years; range, 41-72 years) were evaluated. Tears depicted on MRIs were classified as crescent in 11 patients (24%), longitudinal in three (6.5%), massive contracted in 29 (63%), and cuff arthropathy in three (6.5%). Muscle changes were noted almost exclusively in patients with massive tears and cuff arthropathy (16/32 patients, P = 0.013). MRIs and arthroscopic geometric classifications were in close agreement. Tear type did not correlate with pre- and postoperative physical examination or with postoperative clinical questionnaires scores. CONCLUSION: Geometric RC tear characterizations on preoperative MRIs were closely associated with arthroscopic findings. Postoperative results were not affected by the geometric pattern of the tears.

Fixation of humeral surgical neck fracture using contoured pins versus straight pins: a mechanical study.

The conventional procedure for displaced fracture of the surgical neck of the humerus uses straight pins inserted from the lateral aspect towards the head of the humerus. The objective of this study was to compare the mechanical properties of fixation by contoured (curved) pins to those fixed with regular straight pins. A transverse osteotomy was made in 30 fresh-frozen sheep humeri in the proximal metaphyseal bone region, and pins were inserted using either three parallel straight pins or three contoured pins in different planes. The assemblies were subjected to bending or rotational stresses at the fracture site. Loads versus deformations were acquired during loading and rigidity was calculated. Results showed that in bending, fixation with straight pins was 31% more rigid compared to contoured pins (p < 0.001), and in torsion, fixation using contoured pins was 21% more rigid compared to straight pins (p < 0.001). A combination of the two fixation types should be considered.