A Morphometric Analysis of Hamate Autograft for Proximal Scaphoid Reconstruction.

Objective Recently, authors have investigated using the proximal hamate as osteochondral autograft for proximal pole scaphoid reconstruction in the case of nonunion with avascular necrosis. The aim of our study was to analyze the morphology and anatomic fit of the proximal hamate compared with the proximal pole of the scaphoid using cadaveric specimens. Materials and Methods Ten cadaver specimens (five males and five females) were dissected. Scaphoid and proximal hamate bones were measured by two independent investigators using electronic calipers and radius of curvature gauges. After measurements were determined to have good correlation, the average value of the two observers' measurements were used for further analysis. Sagittal radius of curvature (ROC), coronal ROC, depth, width, and maximum graft length were compared. Results The average depth of the scaphoid proximal pole was 12.3 mm (standard deviation [SD] = 1.12) compared with 11.3 mm (SD = 1.24) for the proximal hamate ( p = 0.36). The average width was 7.8 mm (SD = 1.00) in the scaphoids compared with 8.6 (SD = 1.05) in the hamates ( p = 0.09). There was also no significant difference in the sagittal ROC between hamates (9.1 mm, SD = 1.13) and scaphoids (9.5 mm, SD = 0.84; p = 0.36). All of these average measurements were within 1 mm. There was a significant difference between the coronal ROC of the hamate (23.4 mm) and scaphoid (21.1 mm) bones in our samples ( p = 0.03). Females were on average smaller than their males, but there was no significant difference in fit based on sex alone. Conclusion The proximal pole of the hamate has similar morphology and size as the scaphoid, with similar depth, width, and sagittal ROC. It has potential as an osteochondral autograft for proximal pole scaphoid reconstruction.

Early complications of acromioclavicular joint reconstruction requiring reoperation.

PURPOSE: Prior studies have reported high complication rates with acromioclavicular joint reconstruction (ACJR). However, many of these reports have suffered from small sample sizes and inclusion of older surgical techniques. The purpose of this study was to determine the rates of early complications requiring reoperation in patients treated with ACJR. METHODS: From 2007 to 2011, patients who were treated with ACJR were identified using the PearlDiver database, a large insurance database in the USA. The following reoperations were then queried from this patient cohort: irrigation and debridement within 30 days of index surgery, manipulation under anaesthesia (MUA) of the shoulder joint within 3 months of index surgery, and revision ACJR, distal clavicle excision, and removal of hardware within 6 months of index surgery. RESULTS: In total, 2106 patients treated with ACJR were identified. The reoperation rates for irrigation and debridement, MUA, revision ACJR, distal clavicle excision, and removal of hardware were 2.6, 1.3, 4.2, 2.8, and 6.2 %, respectively. Patients ≥35 years of age and females more likely to undergo a reoperation after ACJR. Specifically, patients ≥35 years of age were more likely to undergo MUA and revision ACJR, while patients ≥50 years of age were more likely to undergo an irrigation and debridement. Females were more likely than males to undergo revision ACJR and distal clavicle excision. CONCLUSIONS: Older patients and females were more likely to experience postoperative complications requiring reoperations, including revision ACJR, distal clavicle excision, and irrigation and debridement. By analysing a large cohort of patients across multiple centres and providers, this study provides valuable insight into the recent complication profiles of ACJR, allowing surgeons to appropriately counsel patients on the risks of these procedures. LEVEL OF EVIDENCE: IV.

The suitability of human adipose-derived stem cells for the engineering of ligament tissue.

Rupture of the anterior cruciate ligament (ACL) is the one of the most common sports-related injuries. With its poor healing capacity, surgical reconstruction using either autografts or allografts is currently required to restore function. However, serious complications are associated with graft reconstructions and the number of such reconstructions has steadily risen over the years, necessitating the search for an alternative approach to ACL repair. Such an approach may likely be tissue engineering. Recent engineering approaches using ligament-derived fibroblasts have been promising, but the slow growth rate of such fibroblasts in vitro may limit their practical application. More promising results are being achieved using bone marrow mesenchymal stem cells (MSCs). The adipose-derived stem cell (ASC) is often proposed as an alternative choice to the MSC and, as such, may be a suitable stem cell for ligament engineering. However, the use of ASCs in ligament engineering still remains relatively unexplored. Therefore, in this study, the potential use of human ASCs in ligament tissue engineering was initially explored by examining their ability to express several ligament markers under growth factor treatment. ASC populations treated for up to 4 weeks with TGFß1 or IGF1 did not show any significant and consistent upregulation in the expression of collagen types 1 and 3, tenascin C and scleraxis. While treatment with EGF or bFGF resulted in increased tenascin C expression, increased expression of collagens 1 and 3 were never observed. Therefore, simple in vitro treatment of human ASC populations with growth factors may not stimulate their ligament differentiative potential.

Stress fractures of the lateral rays in the cavovarus foot: indication for surgical intervention.

Lateral ray stress fractures are a known complication of the cavovarus foot deformity. Malpositioning of the forefoot and hindfoot leads to increased pressure on the heel and lateral rays, resulting in significant morbidity. Patients with nonprogressive deformities can be managed surgically or nonsurgically in an attempt to decrease adverse events. It is often difficult to predict which patients will benefit most from a surgical intervention. This article describes 2 model cases of stress fractures in patients with nonprogressive cavovarus foot deformities. Patient 1 was an active patient with a minor, flexible cavovarus deformity, and patient 2 was a relatively inactive patient with a severe, fixed deformity. These cases serve to illustrate a spectrum of the 2 major risk factors for the development of a stress fracture of the lateral rays: severity of deformity and activity level of the patient. We believe the relationship between these 2 risk factors constitutes a threshold that allows the development of a stress fracture to serve as an adequate marker for surgical intervention. Within this patient population, a stress fracture indicates that given a patient's lifestyle, his or her deformity is sufficient enough to cause significant and repeated morbidity. Surgical restoration of the foot to plantigrade will eliminate the increased forces to the lateral metatarsals and decrease the incidence of further injury. Thus, stress fractures of the lateral rays in patients with nonprogressive cavovarus deformities should be considered an indication for surgical intervention.

Variant of the extensor pollicis tertius: a case report on a unique extensor muscle to the thumb.

Variations on muscular and tendinous connections of the hand occur frequently in the human population and are often discovered during routine surgical procedures and cadaveric dissections. A knowledge of such anomalies is important to the physician in order to avoid unintentional damage to healthy tendons during surgical procedures. In addition, accessory tendons have the potential to be used in the repair or replacement of damaged tendons through surgical transfer or transplantation. Here we describe a unique variant of the extensor pollicis tertius muscle that has its origin at the proximal end of the extensor indicis muscle and inserts on the tendon of the extensor pollicis longus at the proximal shaft of the proximal phalanx of the thumb.

Liquid flow focused by a gas: jetting, dripping, and recirculation.

The liquid cone-jet mode can be produced upon stimulation by a coflowing gas sheath. Most applications deal with the jet breakup, leading to either of two droplet generation regimes: Jetting and dripping. The cone-jet flow pattern is explored by direct axisymmetric volume of fluid (VOF) numerical simulation; its evolution is studied as the liquid flow rate is increased around the jetting-dripping transition. As observed in other focused flows such as electrospraying cones upon steady thread emission, the flow displays a strong recirculating pattern within the conical meniscus; it is shown to play a role on the stability of the system, being a precursor to the onset of dripping. Close to the minimum liquid flow rate for steady jetting, the recirculation cell penetrates into the feed tube. Both the jet diameter and the size of the cell are accurately estimated by a simple theoretical model. In addition, the transition from jetting to dripping is numerically analyzed in detail in some illustrative cases, and compared, to good agreement, with a set of experiments.