Investigation on the site of coronal deformities in Hallux valgus.

Hallux valgus (HV) is a common foot deformity that is more prevalent in females, characterised by abnormal adduction of the first metatarsal (MT) and valgus deviation of the phalanx on the transverse plane. Increasing evidence indicates that HV is more than a 2D deformity but a 3D one with rotational malalignment. Pronation deformity is seen during clinical examination for HV patients, but the exact origin of this rotational deformity is still unknown. Some attribute it to first tarsometatarsal (TMT) joint rotation, while others attribute it to intra-metatarsal bony torsion. In addition, the correlation between the rotational and transverse plane deformity is inconclusive. Identifying the origin of the rotational deformity will help surgeons choose the optimal surgical procedure while also enhancing our understanding of the pathophysiology of HV. This study aims to (1) develop an objective method for measuring the first MT torsion and first TMT joint rotation; (2) investigate the exact location of the coronal deformity in HV; (3) investigate the relationship between the severity of deformity on the transverse and coronal planes as well as the correlation between deformity severity and foot function/symptoms in HV. Age-matched females with and without HV were recruited at the Foot and Ankle Clinic of the Department of Orthopaedics and Traumatology. Computed tomography was conducted for all subjects with additional weight-bearing dorsal-plantar X-ray examination for HV subjects. Demographic information of all subjects was recorded, with symptoms and functions related to HV evaluated. The intra-class correlation was used to explore the relationship between deformities on different planes and the deformity severity and functional outcomes, respectively. An Independent t-test was used to compare joint rotation and bone torsion degrees. TMT joint rotation is significantly correlated with foot function. HV patients had more TMT joint rotation but not MT torsion compared to normal controls. No relationship was found between the coronal rotation and the 1,2-intermetatarsal angle (IMA) or Hallux valgus angle (HVA) on the transverse plane. Our results indicate that coronal deformities in HV may originate from TMT joint rotation. In addition, the severity of the TMT joint coronal rotation correlates with worse foot function; thus, multi-plane assessment and examination will be necessary for more precise surgical correction.

Graft healing after anterior cruciate ligament reconstruction (ACLR).

Anterior cruciate ligament reconstruction (ACLR) is a commonly performed procedure in Orthopaedic sports medicine. With advances in surgical techniques providing better positioning and fixation of the graft, subsequent graft failure to certain extent should be accounted by poor graft healing. Although different biological modulations for enhancement of graft healing have been tried in different clinical and animal studies, complete graft incorporation into bone tunnels and the "ligamentization" of the intra-articular part have not been fully achieved yet. Based on the understanding of graft healing process and its failure mechanism, the purpose of this review is to combine both the known basic science & clinical evidence, to provide a much clearer picture of the obstacle encountered in graft healing, so as to facilitate researchers on subsequent work on the enhancement of ACL graft healing.

Engineering multi-tissue units for regenerative Medicine: Bone-tendon-muscle units of the rotator cuff.

Our body systems are comprised of numerous multi-tissue units. For the musculoskeletal system, one of the predominant functional units is comprised of bone, tendon/ligament, and muscle tissues working in tandem to facilitate locomotion. To successfully treat musculoskeletal injuries and diseases, critical consideration and thoughtful integration of clinical, biological, and engineering aspects are necessary to achieve translational bench-to-bedside research. In particular, identifying ideal biomaterial design specifications, understanding prior and recent tissue engineering advances, and judicious application of biomaterial and fabrication technologies will be crucial for addressing current clinical challenges in engineering multi-tissue units. Using rotator cuff tears as an example, insights relevant for engineering a bone-tendon-muscle multi-tissue unit are presented. This review highlights the tissue engineering strategies for musculoskeletal repair and regeneration with implications for other bone-tendon-muscle units, their derivatives, and analogous non-musculoskeletal tissue structures.

Glucocorticoids suppress proteoglycan production by human tenocytes.

BACKGROUND: The role of glucocortiocid injection therapy in spontaneous tendon rupture is controversial. We hypothesized that glucocorticoids suppress proteoglycan production in tendon and studied the in vitro effects of dexamethasone and triamcinolone on proteoglycan production by cultured human tenocytes. MATERIAL AND METHODS: We obtained primary cultures of human tenocytes from explants of healthy human patellar tendon. The human tenocytes were treated with 1 microM dexamethasone or 1 microM triamcinolone. The amount of proteoglycan production was measured by 35S-sulfate incorporation assay and compared with control cultures. The reversibility of the effect of dexamethasone by co-incubation with 10 ng platelet-derived growth factor (PDGFBB) was also tested. RESULTS: Treatment with 1 microM triamcinolone reduced the amount of 35S-sulfate incorporation to 80% of control cultures (p = 0.007), whereas 1 microM dexamethasone reduced it to 72% (p = 0.01). Co-incubation of 10 ng/mL PDGFBB with 1 microM dexamethasone returned the 35S-sulfate incorporation to a level that was significantly higher than for dexamethasone treatment alone (108%; p = 0.01). INTERPRETATION: Glucocorticoids suppressed proteoglycan production in cultured human tenocytes. The suppression by dexamethasone was reversed by simultaneous addition of PDGFBB. Suppressed proteoglycan production may affect the viscoelastic properties of tendon and increase the risk of spontaneous rupture.

Effect of dexamethasone on cultured human tenocytes and its reversibility by platelet-derived growth factor.

BACKGROUND: Many cases of tendon rupture after glucocorticoid injections have been reported in the literature. Despite previous studies on the histological and biomechanical changes in tendons after glucocorticoid injections, the role of glucocorticoid in causing tendon rupture still remains controversial. The objective of this study was to determine whether glucocorticoid has deleterious effects on the cellular metabolism and collagen production of cultured human tenocytes and the reversibility of these effects by platelet-derived growth factor-BB (PDGFBB). METHODS: Primary cultures of human tenocytes obtained from explants of healthy patellar tendon, harvested during anterior cruciate ligament reconstructions, were performed. The effects on cell viability, cell proliferation, and induction of apoptosis were measured by [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, 5-bromo-deoxyuridine incorporation, and DNA fragmentation assay, respectively. The effect on collagen synthesis was measured by (3) H-proline incorporation assay. RESULTS: The number of viable cells was decreased, in a dose-dependent manner, by the administration of 10 (-9) to 10 (-4) -M dexamethasone. This dose range also suppressed cell proliferation. No apoptotic effect was detected. Treatment with 10 (-6) -M dexamethasone significantly reduced the amount of collagen synthesis. Co-incubation with 10 ng/mL of PDGFBB significantly reversed the effects caused by 10 (-6) -M dexamethasone. CONCLUSIONS: Dexamethasone significantly decreased cell viability, suppressed cell proliferation, and reduced collagen synthesis in cultured human tenocytes. The effects were reversed by the simultaneous administration of PDGFBB.