Preclinical biological and physicochemical evaluation of two-photon engineered 3D biomimetic copolymer scaffolds for bone healing.

A major challenge in orthopedics is the repair of large non-union bone fractures. A promising therapy for this indication is the use of biodegradable bioinspired biomaterials that stabilize the fracture site, relieve pain and initiate bone formation and healing. This study uses a multidisciplinary evaluation strategy to assess immunogenicity, allergenicity, bone responses and physicochemical properties of a novel biomaterial scaffold. Two-photon stereolithography generated personalized custom-built scaffolds with a repeating 3D structure of Schwarz Primitive minimal surface unit cell with a specific pore size of ∼400 µm from three different methacrylated poly(d,l-lactide-co-ε-caprolactone) copolymers with lactide to caprolactone monomer ratios of 16 : 4, 18 : 2 and 9 : 1. Using in vitro and in vivo assays for bone responses, immunological reactions and degradation dynamics, we found that copolymer composition influenced the scaffold physicochemical and biological properties. The scaffolds with the fastest degradation rate correlated with adverse cellular effects and mechanical stiffness correlated with in vitro osteoblast mineralization. The physicochemical properties also correlated with in vivo bone healing and immune responses. Overall these observations provide compelling support for these scaffolds for bone repair and illustrate the effectiveness of a promising multidisciplinary strategy with great potential for the preclinical evaluation of biomaterials.

Novel Tenascin-C Haplotype Modifies the Risk for a Failure to Heal After Rotator Cuff Repair.

BACKGROUND: Several single-nucleotide polymorphisms (SNPs) in the TNC gene have recently been found to be associated with degenerative rotator cuff tears. HYPOTHESIS: Exonic SNPs in the TNC gene are related to the risk for a failure to heal after rotator cuff repair. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A total of 302 patients from the Vienna area and European Caucasian ancestry underwent mini-open rotator cuff repair for a full-thickness superior or posterosuperior tear and were assessed for the integrity of the repair 1 year postoperatively with a real-time 7.5- to 10-MHz ultrasound linear array transducer. Outcomes were classified as intact (complete footprint coverage), small (<200 mm2), or large (≥200 mm2) recurrent defect. Patients were genotyped for 15 previously identified risk SNPs within a 49-kbp segment of the TNC gene with the KASP genotyping technology or the Ion-Torrent Personal Genome Machine System. RESULTS: All recurrent defects were atraumatic failures, and the overall failure rate was 39.7%. Of the traditional risk factors, only the initial tear size was significantly associated with a failure to heal. In a multinomial logistic regression model, the T allele at rs1138545 [C>T] was protective for a large recurrent defect (odds ratio = 0.16; 95% CI, 0.09-0.31). The role of rs1138545 was further backed by haplotype analysis, which showed that the combination of the C allele at rs1138545 [C>T], the A allele at rs2104772 [A>T], and the G allele at rs10759752 [A>G] formed the risk-related haplotype [CAG]. The CAG haplotype was associated with large recurrent defects ( P < .0001; haplotype frequency, 0.394; haplotype score, 4.518). Exonic marker rs1138545 transcribed into all isoforms of the TNC protein, whereas exonic marker rs2104772, which has been associated with Achilles tendinopathy before, transcribed only into large isoforms of the TNC protein. CONCLUSION: Recurrent defects after rotator cuff repairs are clinically relevant, and a heritable component of the disorder is plausible on the basis of a genetic association with 8 TNC variants. Characterization of TNC sequences that favor tendon healing will help engineer new products in regenerative medicine.

Candidate gene approach identifies six SNPs in tenascin-C (TNC) associated with degenerative rotator cuff tears.

Evidence for a heritable predisposition to rotator cuff tears (RCTs) is growing. Unrelated Caucasian individuals with surgically diagnosed full thickness RCTs (cases) and elderly Caucasian controls with intact rotator cuffs were screened for differences at the candidate genes: TNC, Col5A1, TIMP-1, MMP-1, MMP-2, MMP-3, MMP-9, and MMP-13. A first cohort (59 cases; 32 controls) was genotyped with the Sequenom MassARRAY iPLEX system. Of 142 SNPs within about 67-kbp of the TNC gene, 30 were tested for differences in proportions between cases and controls. A second, matched cohort (96 patients; 44 controls) was also genotyped for the same 30 SNPs, but with the KASP™ genotyping technology. Combining the two cohorts and after Bonferroni correction, six SNPs were significantly associated with RCT. Compared to controls, RCT patients showed a significantly higher rate of homozygosity at rs72758637, rs7021589, and rs1138545; a significantly higher rate of heterozygosity at rs10759753, rs3789870, and rs7035322 and a higher minor allele frequency at rs3789870. Rs1138545, a missense SNP in exon10 might be of biological significance because it varies the amino acid sequence close to the TNC-FNIII5 domain. The FNIII5 domain binds multiple growth factors and co-ligates with integrins during tendon healing. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:894-901, 2017.

The Scarf Osteotomy with Minimally Invasive Lateral Release for Treatment of Hallux Valgus Deformity: Intermediate and Long-Term Results.

BACKGROUND: Little is known about the long-term results of surgical correction of hallux valgus deformity, in particular, the recurrence rate and factors leading to recurrence. METHODS: Of one hundred and eight patients (115 feet) who underwent a Scarf osteotomy, ninety-three patients (ninety-three feet) were examined at an average duration of follow-up of 124 months. Clinical examination before surgery and at the time of final follow-up included an evaluation of range of motion, pain as measured with a visual analog scale, and American Orthopaedic Foot & Ankle Society (AOFAS) scores. The Foot and Ankle Outcome Score (FAOS) was also assessed postoperatively. Radiographic data were evaluated preoperatively, at six weeks postoperatively, and at the time of final follow-up. Additional radiographic data were available for seventy-nine patients of the same patient cohort at an average of twenty-seven months postoperatively. RESULTS: The median overall AOFAS score improved from 57 points preoperatively to 95 points at the time of final follow-up. All radiographic measurements (hallux valgus angle [HVA], intermetatarsal angle [IMA], distal metatarsal articular angle [DMAA], and sesamoid bone position) showed significant (p < 0.05) improvement at the time of final follow-up compared with preoperatively. The rate of recurrence (an HVA of ≥20°) at the time of final follow-up was 30%. We were unable to determine if recurrence resulted in functional impairment or consequences for quality of life. CONCLUSIONS: The recurrence rate after ten years was 30%, and a higher final HVA resulted in higher pain levels. The limitations imposed by nonvalidated outcome measures precluded conclusions about the influence of HVA on function or quality of life.

Long-term survivorship of rotator cuff repairs using ultrasound and magnetic resonance imaging analysis.

BACKGROUND: Important differences in clinical outcomes likely exist between patients with healed and nonhealed rotator cuff repairs. The survival probability of rotator cuff repairs has not been published in a time-dependent manner up to now. HYPOTHESES: Recurrent tears occur more frequently in the early postoperative period. Early failures of the repair are a prognostic factor for the long-term outcome. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A series of 107 consecutive patients undergoing arthroscopically assisted mini-open repair of the rotator cuff between 1998 and 2002 were evaluated in a prospective study. Of these, 95 patients finished the study after a maximum follow-up of 11 years. The evaluation included 1 postoperative magnetic resonance imaging scan as well as multiple ultrasonographies and determinations of the American Shoulder and Elbow Surgeons (ASES) and Constant scores at 3 months, 6 months, 1 year, and then yearly with a median follow-up of 96 months. RESULTS: The overall failure rate was 33% (35 of 107). The survivorship analysis revealed that 74% of all failures occurred atraumatically in the first 3 months and 11% occurred between the third and the sixth month after the repair. The remaining reruptures (14%) happened 2 to 5 years postoperatively and were related to sports activities or direct trauma. The overall clinical results did not deteriorate over time. The parameters healed tendon, rerupture of less than 2 cm(2), and rerupture of more than 2 cm(2) at 6 months were predictors of the gender- and age-adjusted (normalized) Constant score at 84 months (P < .0001). CONCLUSION: The majority of recurrent tears occurred in the first 3 months after surgical repair. The parameters "recurrent tear" as well as "healed tendon" evaluated at 6 months postoperatively appear to be predictors for the clinical outcomes at 7 years. Efforts to improve healing during the initial 3 months have long-term implications for maintenance of cuff integrity and clinical outcomes.

Preparation and pre-vivo evaluation of no-carrier-added, carrier-added and cross-complexed [(68)Ga]-EDTMP formulations.

PURPOSE: The present study aimed to develop convenient preparation and quality control protocols for [(68)Ga]-EDTMP, a potential radiotracer for skeletal PET imaging. Furthermore, bone binding characteristics with special focus on the influence of carrier addition were evaluated. METHODS: No-carrier-added (nca), carrier-added and novel cross-complexed [(68)Ga]-EDTMP formulations were prepared using [(68)Ga]-gallium chloride and a commercial EDTMP kit. Respective bone binding characteristics were determined on the basis of an established in-vitro method using hydroxyapatite and human bone powders as binding matrices. RESULTS: Pre-vivo evaluation of nca [(68)Ga]-EDTMP yielded irreversible binding on the mineral bone phase characterised by fast binding kinetics. Generally, nca [(68)Ga]-EDTMP showed low uptake values comparable to nca [(99m)Tc]-EDTMP. Interestingly, the bone binding affinity of [(68)Ga]-EDTMP could be increased by the addition of carriers, presumably by changing the complex structure. CONCLUSIONS: This fast and reliable preparation protocol could enable small PET facilities without onsite cyclotron to perform PET bone scans. A comparison of all cross-complexed [(68)Ga]-EDTMP preparations further strengthens the recently presented "foreign carrier theory", which highlights carrier addition as a factor strongly affecting bone uptake of radiolabelled polyphosphonates. The clinical applicability of [(68)Ga]-EDTMP - particularly with respect to lesion specificity and sensitivity - should be clarified in forthcoming in-vivo studies.

Pre vivo, ex vivo and in vivo evaluations of [68Ga]-EDTMP.

INTRODUCTION: The objectives of this study were to develop a simple preparation method for [68Ga]-EDTMP and to evaluate the applicability of [68Ga]-EDTMP as a potential positron emission tomography (PET) bone imaging agent using pre vivo, ex vivo and in vivo models. METHODS: [68Ga]-EDTMP was prepared using 68Ga]-gallium chloride eluted from the 68Ge/68Ga generator and commercially available Multibone kits. Binding affinity to bone compartments was evaluated using a recently established pre vivo model. In vivo (microPET) and ex vivo experiments were performed in mice, and the results of which were compared with those obtained with [18F]-fluoride. RESULTS: [68Ga]-EDTMP was accessible via simple kit preparation and predominantly accumulated in bone tissue in vivo, ex vivo and pre vivo. Binding to mineral bone was irreversible, and low binding was observed in organic bone. In vivo microPET evaluation revealed predominant uptake in bone with renal excretion. Compared with [18F]-fluoride, the uptake was lower and the PET image quality was reduced. CONCLUSIONS: From the present evaluation, apart from the autonomy for PET centers without an onsite cyclotron, the advantage of [68Ga]-EDTMP over [18F]-fluoride is not apparent and the future clinical prospect of [68Ga]-EDTMP remains speculative.

Anatomical reconstruction for Reverse Hill-Sachs lesions after posterior locked shoulder dislocation fracture: a case series of six patients.

INTRODUCTION: Posterior locked shoulder dislocation fracture is a rare injury. Impression fractures of the humeral articular surface are common with this injury. Different methods exist to restore impression fractures. We present a case series and the results of six patients that had an anatomical repair with spongiotic autograft/allograft for humeral head impression fractures after locked posterior shoulder dislocation. MATERIAL AND METHODS: Six patients with an average age of 52.5 years at time of surgery were included. All patients had an anteromedial impression fracture, one patient had an additional two part fracture. The injury was caused by epileptic seizures in five and by direct trauma in one patient. The diagnosis was made on the day of the injury for two patients (33%). For the other patients the time span between the injury and the diagnosis ranged between 5 and 180 days. The impressed cartilage of the defect was first elevated in one piece, the defect filled with the graft and the cartilage fixed on top of the graft by Mitek ancres introduced under the affected area. One patient had an additional two-part fracture that was fixed separately. RESULTS: At a mean time follow-up of 62.7 (18-95) months the result was found to be excellent for two patients and good for four patients with a mean Constant Score of 88.2 points (range 83-98). One patient had a redislocation after three months that was fixed by the same method. At the last follow-up no redislocation or graft collapse was seen. CONCLUSION: The proposed method of anatomical head reconstruction by spongiotic auto/allograft proved to be a valid and good method to restore shoulder function and stability.

Transient bone marrow edema syndrome of the knee: clinical and magnetic resonance imaging results at 5 years after core decompression.

PURPOSE: We report on 24 cases of transient bone marrow edema syndrome in 18 patients who underwent core decompression of the knee. METHODS: Diagnosis was made with the use of radiographs, magnetic resonance imaging (MRI), and core biopsy testing. Arthroscopic surgery and core decompression were carried out in all patients, and MRI was performed again, 5 years after surgery was performed. RESULTS: Medial and lateral femoral condyles were affected in 15 and 7 knees, respectively. In all, 6 patients presented with bilateral involvement of the knees (migrating transient bone marrow edema syndrome). Two of these patients had affections of the medial and lateral compartments within the same knee at different times, consistent with intra-articular regional bone marrow edema syndrome. Core biopsy specimens showed areas of bone marrow edema and vital trabeculae covered by osteoblasts and osteoid seams. Resolution of symptoms and normalization of MRI findings occurred in all patients within 12 weeks after surgery. CONCLUSIONS: Migrating bone marrow edema was found in a high percentage (33%) of patients at 5-year follow-up; however, all patients were clinically asymptomatic, and signal alterations on MRI had resolved completely. The high incidence of migrating bone marrow edema, the lack of osteonecrotic regions in our specimens, and the fact that none of these cases progressed to spontaneous osteonecrosis seem to further support the contention that bone marrow edema syndrome of the knee is a distinct entity. LEVEL OF EVIDENCE: Level II, diagnostic study; development of diagnostic criteria on the basis of consecutive patients and with universally applied reference gold standard.

In vitro evaluation of no carrier added, carrier added and cross-complexed [90Y]-EDTMP provides evidence for a novel "foreign carrier theory".

The present study focused on the preparation of novel bone tracers containing yttrium as radionuclide or carrier. Moreover, these preparations were comparatively evaluated in vitro on the basis of a recently presented pre vivo model comprising binding studies on synthetic and human bone powder. It was shown that among the therapeutic radionuclides, no carrier added [(90)Y]-EDTMP exceeded [(188)Re]-EDTMP while yielding lower binding values than [(153)Sm]-EDTMP. Furthermore, the authors investigated the influence of "foreign" carriers added to [(90)Y]-EDTMP, [(99m)Tc]-EDTMP and [(111)In]-EDTMP by the method of cross-complexation. The findings reveal a new paradigm: a carrier more foreign to the complexed radionuclide causes a higher binding increase on human bone matrices in vitro than a more "related" carrier.

Binding studies of [18F]-fluoride and polyphosphonates radiolabelled with [99mTc], [111In], [153Sm] and [188Re] on bone compartments: verification of the pre vivo model?

INTRODUCTION: Although the first polyphosphonates (PP) were introduced to nuclear medicine as bone imagers in the early 70s, mechanisms involved in uptake still remain speculative. Controversies range from adsorption onto the mineral phase with disputed binding to the organic phase, over incorporation into the mineralisation process to a combination of both mechanisms. Other factors such as solubility of the complex, concentration of ligand or effects of the radionuclide have also been discussed as possible parameters influencing bone uptake. Therefore, the present work aimed to verify the recently presented pre vivo model which was developed to rate the influence of various factors on the binding of differently radiolabelled PP and [18F]-fluoride on synthetic bone matrix. METHODS: Radiolabelled polyphosphonates and [18F]-fluoride were added to a vial containing lyophilised and milled spongiosa (Sp) or cortical bone (Co) in Hank's Balanced Salt Solution. After incubation, the radioactivity was measured in the gamma-counter before and after filtration. The percentage of irreversibly bound radioactivity was calculated. Same experiments were performed after decalcification of Sp and Co with hydrochloric acid. RESULTS: Descriptively, [111In] increases the uptake of EDTMP in each case compared to similarly prepared [(99m)Tc]-analogues: [111In]-EDTMP > [(99m)Tc]-EDTMP, [111In]-/In-EDTMP > [(99m)Tc]-/In-EDTMP and [111In]-/Re-EDTMP > [(99m)Tc]-/Re-EDTMP. [188Re]-EDTMP shows higher binding than the carrier-added analogue, contradicting recent in vivo findings of [(188)Re]-PP. However, our findings on human matrix are consistent with those of a previous study using artificial bone material. Binding on decalcified tissue was very low (PP) to moderate ([18F]-fluoride) and reversible. Remarkable is also the unrivalled high uptake of [18F]-fluoride, showing no reduced uptake on Co and Sp as compared to hydroxyapatite (HA) and amorphous calcium phosphate (ACP). CONCLUSION: The binding of the evaluated bone seekers on these human bone matrices follows a comparable pattern as on artificial bone. The present study substantiates the fact that binding predominantly occurs on the inorganic compartment of bone. The best correlation was found between HA and Co. Therefore, HA can serve as a matrix for representative binding studies.

Osteoprogenitor cells and osteoblasts are targets for hepatitis C virus.

The goal of this study was to determine whether human osteoblasts might harbor the hepatitis C virus. We tested for positive-strand and negative-strand (replicative) hepatitis C virus RNA by reverse transcriptase-polymerase chain reaction, by in situ reverse transcriptase-polymerase chain reaction for intracellular localization of the hepatitis C virus, and by amplicon sequencing in in vitro differentiated mature osteoblasts from STRO-1+ osteoprogenitor cells from patients with chronic hepatitis C and from healthy individuals. We only detected the hepatitis C virus genome in STRO-1+ cells and mature osteoblasts from carriers with chronic hepatitis C, and we found hepatitis C virus negative strands expressed sporadically in these patients. Using in situ hepatitis C virus reverse transcriptase-polymerase chain reaction, we determined that the percentage of infected carrier osteoblasts ranged from 8.0-15.3%. These data provide evidence of hepatitis C virus presence and replication in human osteoprogenitors and osteoblasts, which may have important implications for bone allograft processing.

Sonographic versus magnetic resonance arthrographic evaluation of full-thickness rotator cuff tears in millimeters.

Preoperative knowledge of full-thickness rotator cuff tear size is important in counseling patients because tear size affects the choice of surgical techniques and the functional outcome of surgery. Twenty-six shoulders of twenty-five consecutive patients were included in a prospective study that compared the preoperative accuracy of magnetic resonance arthrography and ultrasonography for tear size in millimeters with intraoperative findings. No significant differences were found between intraoperative, ultrasonographic, and magnetic resonance arthrographic data for the width of tears. Adoption of a "curved line measurement" for ultrasonographic evaluation of large tears eliminated the tendency of ultrasonography to underestimate tears greater than or equal to 35 mm in width. No significant differences were found between intraoperative, ultrasonographic, and magnetic resonancearthrographic data for retraction of tears. However, a limitation of ultrasonography to evaluate retractions of more than 30 mm was found. Therefore, ultrasound is of equal value for tears less than 30 mm, but magnetic resonance arthrography is more accurate for tears greater than 30 mm.