Metacarpal-phalangeal Joint Research Articles

Electromyographic Bridge-a multi-movement volitional control method for functional electrical stimulation: prototype system design and experimental validation.

The voluntary participation of the paralyzed patients is crucial for the functional electrical stimulation (FES) therapy. In this study, we developed a strategy called "EMG Bridge" (EMGB) for volitional control of multiple movements using FES technique. The surface electromyography (sEMG) signals of the agonist muscles were transformed to stimulation pulses with various pulse width and frequency to stimulate the target paralyzed muscles using MAV/NSS co-modulation (MNDC) algorithm we proposed recently. Motion pattern classification based on linear discriminant analysis (LDA) was included to recognize the motion status and mapping the sEMG detection channel to the corresponding stimulation channel. A prototype EMGB system was built for real-time control of four hand movements. The test results showed that the movements can be reproduced with a successful rate of 92.5±3.5%. The angle trajectory of wrist joint and metacarpal-phalangeal joint can be mimicked with a maximum cross-correlation coefficient > 0.84 and a latency less than 300 ms.

Pyogenic Arthritis of the Fingers and the Wrist: Can We Shorten Antimicrobial Treatment Duration?

BackgroundPyogenic arthritis of the small joints of the hand and wrist is a known but poorly described entity. The objective of this work was to characterize the clinical presentation, antimicrobial treatment, and surgical interventions of native small joint arthritis (SJA) treated in our tertiary center.MethodsAccording to predefined variables, medical records of adult patients with SJA treated in a Swiss university hospital between 2005 and 2013 were retrospectively analyzed.ResultsThe median age of 97 patients (101 joints) was 52 years (interquartile range [IQR], 38–68 years); 52% had no comorbidity. Small joint arthritis of the second and third fingers accounted for 53% of infections, with metacarpal-phalangeal and proximal interphalangeal joints most commonly involved. Of 86 (89%) episodes with an exogenous source, 63 (65%) followed a trauma. The most commonly isolated microorganism was Staphylococcus aureus (38%), followed by β-hemolytic streptococci (13%) and Pasteurella spp (11%). Eighty-seven episodes (89 joints) in patients with follow-up examinations were included in treatment and outcome analyses. Up to 2 surgical interventions were required to cure infection in 74 (83%) joints. Median antimicrobial treatment duration was 14 days (IQR, 12–28 days), with amoxicillin/clavulanate administered in 74 (85%) episodes. At follow up, cure of infection was noted in all episodes and good functional outcome in 79% of episodes.ConclusionsSmall joint arthritis shows considerable differences from clinical patterns reported for larger joints. In our series, the outcome was good with no more than 2 surgical interventions and median treatment duration of 14 days in 79% of episodes.

Clinical observation of minor external fixation combined with Kirschner wire for open comminuted fracture of metacarpophalangeal joint

To explore the method and therapeutic effect of minor external fixation combined with Kirschner Treatment for open comminuted fracture of metacarpophalangeal joint. From January 2013 to December 2014, 13 patients with open comminuted fracture of metacarpophalangeal joint were treated by minor external fixation combined with Kirschner wire, including 9 males and 4 females, aged from 18 to 56 years old with an average of 35 years old.According to Gustilo classification, 8 cases were type II, 4 cases were type IIIA, and 1 case was type IIIB. The time from injury to operation ranged from 2 to 7 h with an average of 5 h. All fractures were involved with metacarpal phalangeal joint surface. Fracture healing time and postoperative complications were observed, TAM scoring system by Hand Surgery Association of Chinese Medical Association was used to evaluate functional recovery. All patients were followed up from 3 to 12 months with an average of 7 months. All fractures were obtained bone healing, and the time ranged from 4 to 6 weeks with an average of (4.6±1.0) weeks. No broken and loose needle, pin track infections, malunion, loose bracket, reflection sexual sense of neurological malnutrition occurred. According to TAM scoring system, 7 cases obtained excellent results, 4 cases good, 1 case moderate and 1 case poor. Minor external fixation combined with Kirschner wire for open comminuted fracture of metacarpophalangeal joint has advantages of simple operation, good stability and which could be adjusted at the later stage, less damage for soft tissue periosteum, low inflammatory, earlier functional exercise. It is worth to be popularized and applied.

Treatment of complex metacarpal defects with free chimeric iliac osteocutaneous flaps

Objective: The aim of this report is to present the clinical results of using free chimeric iliac osteocutaneous flaps based on the periosteal branch of the superficial circumflex iliac artery (SCIA) in complex metacarpal reconstructions.Methods: Reconstruction using free chimeric iliac osteocutaneous flaps was performed in a series of seven patients who underwent metacarpal reconstruction for complex metacarpal defects between March 2009 and March 2012. The procedure was performed for bone and soft tissue losses associated with posttraumatic infections (four patients) and posttraumatic bone and soft tissue defects (three patients).Results: The skin paddles of the chimeric flaps had a median size of 3 × 7 cm, and the iliac segments had a mean size of 1 × 1 × 3 cm. The median follow-up time was 18 months. All the flaps survived completely with no signs of infection. Osseous union occurred within a mean period of 3 months, and the range of motion achieved for the metacarpal phalangeal joints was 0–80°. The patients were satisfied with the aesthetic outcome.Conclusions: Chimeric iliac osteocutaneous flaps may be a useful alternative for treating complex metacarpal defects because they yield a thinner skin paddle and less bulky bone segment than traditional flaps.

Joint Ultrasonography of Goats Infected by the Caprine Arthritis Encephalitis Virus

Background: The most important form of caprine arthritis encephalitis virus in the goat is the arthritic, generally observed in animals over eight months of age. Differently in sheep, there is less arthritis incidence, affecting 2-3-year-old animals. The clinical alterations frequently affect goat joints, and an increase in the joint consistency and size is observed. The objective of the present study was to standardize the ultrasound technique to access joints in animals infected with the caprine arthritis encephalitis virus (CAEV), so that it can be a complimentary support tool for diagnosis and animal management.Materials, Methods & Results: Animals were examined from farms located in the municipality of Teresina, state of Piauí, Brazil. For this, the M-Turbo, Sonosite Fujifilm ultrasonography apparatus was used, attached to a linear transducer with 10-13 MHz frequency. The ultrasound examination analyzed three regions: patella-humerus joint, carpal and tarsal joints. The patella-humerus joint was characterized by its concave convex surface. The surface of the head humerus was a fine hyperechoic line composed by the junction between the joint cartilage and the subcontinent bone. The sub patella muscle was visible and its fibers present a parallel and hypoechogenic pattern compared to bone tissue. A discreet muscle edge with echogenicity was observed separating the sub patella and supraspinatus muscles. The surface of the proximal and distal rows of the carpal bones was characterized by fine hyperechogenic lines that formed acoustic shadow. Regarding the bones of the tarsal joint, the surface of the central tarsal joint bone was observed centrally as a fine, hyperechogenic line. The third tarsal joint bone was visualized on the left side and was represented by a thick hyperechoic line, while the fourth tarsal joint bone was observed to the right with a hypoechogenic surface and both formed acoustic shadow.Discussion: Joint inflammation caused by other diseases, such as derived from bacteria of the Micoplasma genus can suggest similar semiological aspects and can present positive results for the joint clinical index. Studies carried out have established measurements of the joints of animals affected by various degrees of arthritis, where absolute values equal or less than 5.5 cm would be indicative of negative arthritis diagnosis, variations between 6.0 and 6.5 cm would be considered suspicious and when equal or greater than 7.0 cm they would be positive. From the anatomical point of view, ultrasound assessment of the joints of the normal animals showed a morphological pattern as observed in dogs, horses and humans. The loss of echogenicity, surface erosions and exposure of subchondral bone observed in goats infected with CAEV were also reported in dogs with patella-humerus osteochondrosis, by the presence of a cartilage flap seen radiographically, or even as cracks, characterized by a hyperechoic line parallel to the subchondral defect, in the ultrasonography examination. The lesions observed in the ultrasound examination showed various degrees of osteoarthritis, with the presence of sound hyperreflection, hyperechogenic areas, cartilage lesions with erosion of the subchondral bone and loss of anatomic limits, and these characteristics were described for the metacarpal phalangeal and metatarsal phalangeal joints of dogs submitted to routine radiographic examination. The ultrasound examination of the joints of normal goats and goats infected with caprine arthritis encephalitis virus allowed the comparative description of normal anatomy, evolution of joint and adjacent soft tissue lesions, generating valuable clinical and surgical information.

Does collagenase injection disrupt or digest the Dupuytren's cord: a magnetic resonance imaging study.

Collagenase clostridium histolyticum has been extensively studied as a treatment modality for Dupuytren's contracture. Its mechanism of action has been documented. It is unknown whether injected collagenase weakens the Dupuytren's cord sufficiently to cause failure during manipulation or if there is digestion and reduction in cord volume. We examined five patients with isolated contractures of the ring or middle metacarpalphalangeal (MP) joint using magnetic resonance imaging (MRI) prior to injection with collagenase and again 1 month following injection. All patients had full correction after manipulation which was maintained at follow-up. The Dupuytren's cord was evaluated with respect to volume, signal intensity, inflammatory changes and continuity. Additionally, signal intensity changes of the flexor tendons and neurovascular structures were recorded. MRI demonstrated cord discontinuity, significant reduction of cord volume and a significant increase in cord signal intensity after treatment with collagenase. There was a slight increase in flexor tendon signal intensity that was not significant. These findings suggest that there may be local chemical dissolution of the cord. Future studies may establish whether or not this will have prognostic implications in terms of correction and recurrence following collagenase injection. IV.

Distal Vibration Perception Threshold in Children Who Toe Walk.

To compare distal vibratory perception threshold and sensation in children who toe walked (TW) and controls. Vibration perception threshold was measured at the metacarpal and metatarsal phalangeal (MCP and MTP) joints in 11 TW and 15 age-matched controls. Mean vibratory threshold (MVT) was calculated for each site; a Pearson correlation coefficient was determined for MVT at MCP and MTP joints. Groups were compared using a Mann-Whitney U test. Parent/caregiver responses on the Short Sensory Profile (SSP) were compared using a χ test. MVTs at the MCP and MTP joints were highly correlated in both groups. MVT was higher in TW compared with controls at each site. Children who TW were more likely to have a total SSP score in the "probable difference" or "definite difference" categories compared with the "no difference" category. Sensation should not be overlooked in the evaluation and clinical management of toe walking.

Hedgehog signalling does not stimulate cartilage catabolism and is inhibited by Interleukin-1β.

BackgroundIn osteoarthritis, chondrocytes adopt an abnormal hypertrophic morphology and upregulate the expression of the extracellular matrix-degrading enzymes, MMP-13 and ADAMTS-5. The activation of the hedgehog signalling pathway has been established in osteoarthritis and is thought to influence both of these processes. However, the role of this pathway in the initiation and progression of osteoarthritis is unclear as previous studies have been unable to isolate the effects of hedgehog pathway activation from other pathological processes. In this study we test the hypothesis that hedgehog pathway activation causes cartilage degradation in healthy cartilage and in an in vitro model of inflammatory arthritis.MethodsIsolated articular chondrocytes from the bovine metacarpal-phalangeal joint were stimulated for up to 24 hours with the agonist, recombinant Indian hedgehog (r-Ihh). ADAMTS-5 and MMP-13 gene expression was quantified by real-time PCR. In addition, healthy bovine cartilage explants were treated with r-Ihh or the hedgehog antagonist, cyclopamine, and sGAG release into the media was measured over 72 hours. Studies were repeated using chondrocytes and cartilage explants from human knee joint. Finally, studies were conducted to determine the effect of hedgehog pathway activation on matrix catabolism in the presence of the pro-inflammatory cytokine, IL-1β.ResultsAddition of r-Ihh activated hedgehog signalling, confirmed by upregulation of Gli1 and Ptch1 expression, but did not increase ADAMTS-5 or MMP-13 expression in bovine or human chondrocytes. Furthermore, r-Ihh did not induce sGAG release in healthy bovine or human cartilage explants. IL-1β treatment induced sGAG release, but this response was not altered by the stimulation or inhibition of hedgehog signalling. Hedgehog pathway activation was downregulated by IL-1β. Conversely, r-Ihh weakly suppressed IL-1β-induced ADAMTS-5 expression.ConclusionOur results show for the first time that Indian hedgehog does not cause extracellular matrix degradation in healthy ex vivo cartilage or in the presence of IL-1β and that IL-1β downregulates Indian hedgehog induced signalling. Thus, we suggest reported hedgehog induced matrix catabolism in osteoarthritis must be due to its interaction with pathological factors other than IL-1β. Hence, hedgehog signalling and its downstream effects are highly context-dependent.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-015-0891-z) contains supplementary material, which is available to authorized users.

Case 1: A six-year-old boy with finger contractures.

A six-year-old boy of Chinese descent presents with a six-month history of finger contractures of the right third and fourth digits. His teacher first noticed his inability to lay his right palm flat. There was no history of trauma or infection to the hand, and no other symptoms were present. The patient denied pain and swelling, and could perform regular activities without limitations. His medical history was negative, other than a possible peanut allergy. He had no history of oral ulcers, conjunctivitis or joint pain, and the remaining review of systems was unremarkable. Initial examination revealed a well-appearing boy with contractures of the right third and fourth metacarpal-phalangeal and proximal interphalangeal joints (Figure 1). In addition, his right fourth digit measured 0.2 cm shorter than the left. A 5 cm brown-coloured thickened lesion with a mild erythematous border was observed on the right palm. His left hand appeared normal and his general physical examination was otherwise normal. Figure 1) Finger contractures and thickened skin lesions in a six-year-old boy Laboratory investigations revealed normal complete blood count, electrolyte levels, liver enzyme levels and renal function. C-reactive protein level, erythrocyte sedimentation rate and complement level were normal. Rheumatoid factor and anti-nuclear antibody were negative. Several months later, a similar lesion appeared on the palmar side of his right wrist.

Looking For The Glass In Hand

HISTORY: An otherwise healthy 22-yo male fell on an outstretched hand shattering a glass mug he was carrying in his right (dominant) hand. He sustained multiple lacerations to the palm, and had no loss of sensation or motion of forearm, wrist, hand, and fingers. He presented urgently for wound care and to ensure there was no retained glass. PHYSICAL EXAMINATION: — Picture attached — No active bleeding — No bony tenderness to palpation — Full range of motion and muscle strength in all digits with no detectable neurovascular deficits DIFFERENTIAL DIAGNOSIS: 1. Lacerations +/-retained foreign bodies TEST AND RESULTS: Plain films of the hand- superficial 1mm x 3mm retained foreign body, proximal to the first metacarpal phalangeal joint metacarpal FINAL WORKING DIAGNOSIS: 1. Laceration with single retained foreign body TREATMENT AND OUTCOMES: 1. After failing to visualize the foreign body on exploration of wounds, an ultrasound was used to localize the foreign body. No other retained fragments were noted. 2. Ultrasound visualization allowed for real-time anatomic location and ensured complete removal of the retained foreign body - a single shard of glass. 3. Retained foreign body(ies) may inhibit wound healing and possibly cause further skin infections. Complete removal of the foreign bod(ies) would improve wound healing and decrease the likelihood of skin infections. 4. With radiographic x-rays, radio opaque foreign body(ies) may or may not be seen. 5. Moreover, radiographic x-rays and technicians may not be readily available to perform such images. 6. Lastly, radiographic x-rays emit radiation albeit minute but more so than ultrasound. 7. Ultrasounds are becoming a mainstay in primary care and sports medicine clinics.

Superficial zone chondrocytes secrete a factor that regulates deep zone cartilage mineralization by modulating polyphosphate levels

Purpose: Articular cartilage is an avascular tissue with a complex depth-dependent zonal architecture with unique matrix composition and organization, vital for maintaining joint function. Osteoarthritis (OA) is a degenerative disease that disrupts this zonal arrangement and manifests initially as loss of the superficial zone (SZ) followed by progressive matrix loss and advancement of the calcified zone into the remaining articular cartilage region. We have shown previously that polyphosphate, a naturally occurring linear polymer of phosphates, can regulate mineralization in articular cartilage. The hypothesis of this study is that superficial zone cells modulate calcification of deep zone cartilage (DZ) by modulating levels of cartilage polyphosphate levels through a soluble factor. Methods: Articular chondrocytes were isolated from either the SZ or DZ of bovine cartilage obtained from the metacarpal-phalangeal joints (6-9 months). The cells were seeded individually on 3D membrane inserts in conditions that favour formation of cartilage tissue and grown in side-by-side co-culture for up to 7 days in mineralization inducing media (MIM, β glycerophosphate). As a control DZ cells were grown in co-culture with DZ cells. To determine if SZ cells were producing a soluble factor, SZ cells were grown alone and the resulting conditioned media (SZ-CM) was collected daily and added to cultures of DZ cells to determine its effect on mineralization. To examine the role of FGF signalling in regulating mineralization, DZ cells were treated with FGF-18 (10ng/mL), or CM supplemented with an FGF-receptor inhibitor (PD173074 60nM) in MIM. Calcium and phosphate contents were determined biochemically. Representative tissues were fixed in formalin and embedded in paraffin. Sections were stained with Von kossa. Polyphosphate (PP) was visualized by staining un-waxed histological sections with DAPI, which shifts the emission spectra to the yellow-green range when it binds to PP. PP was quantified following extraction from the tissues by measurement of phosphate levels after alkaline phosphatase digestion. A minimum of three independent experiments were performed and each condition was done in duplicate or triplicate. Results are expressed as mean ± standard error of the mean and analysed using a one-way analysis of variance followed by Tukey’s post hoc test. Statistical significance was assigned at p < 0.05. Results: Side by side co-culture of DZ cells with SZ cells inhibited DZ mineralization, compared to co-culture with DZ, as demonstrated by significantly decreased calcium and phosphate content and decreased mineral deposits observed by Von Kossa staining. Treatment with SZ-CM inhibited DZ mineralization, resulting in significantly less calcium and phosphate content compared to treatment with DZ-CM suggesting that the cells were producing a soluble factor. SZ-CM was unable to inhibit mineralization after heat treatment or trypsin digestion, suggesting that the factor is a protein. Polyphosphate was present within the matrix of tissue grown in non-mineralizing conditions, and staining diminished in mineralized tissue. Polyphosphate levels were significantly higher in cartilage co-cultured with SZ cells, compared to DZ cells. FGF-18 has been shown to attenuate hypertrophic differentiation and we investigated whether this might be the factor responsible for influencing mineralization. Treatment of DZ cells with FGF-18 mimicked the effects of the SZ-CM, with significantly less mineralization and more polyphosphate accumulation within the tissue. Furthermore, treatment of DZ cells with SZ-CM in the presence of the FGF-receptor inhibitor rescued mineralization, and significantly reduced polyphosphate accumulation within cartilage formed by DZC. Conclusions: SZ cells release a soluble factor, likely a protein as it is sensitive to heat treatment and trypsin digestion, that inhibits mineralization of cartilage formed by DZ cells by up-regulating PP. Further investigation is required to determine if SZ cells secrete a factor that directly or indirectly, by up-regulating FGF-18 expression, inhibits mineralization of cartilage formed by DZC, and whether a single factor or combination of factors is required.

Enhanced SDF-1 and rantes attract the locally injected bone marrow stromal cells to remedy dental biomechanically induced temporomandibular joint osteoarthritic lesions

Enhanced SDF-1 and rantes attract the locally injected bone marrow stromal cells to remedy dental biomechanically induced temporomandibular joint osteoarthritic lesions

Freely Chosen Index Finger Tapping Frequency Is Increased in Repeated Bouts of Tapping

ABSTRACTHealthy individuals (n = 40) performed index finger tapping at freely chosen frequency during repeated bouts and before and after near-maximal muscle action consisting of 3 intense flexions of the index finger metacarpal phalangeal joint. One experiment showed, unexpectedly, that a bout of tapping increased the tapping frequency in the subsequent bout. Thus, a cumulating increase of 8.2 ± 5.4% (p < .001) occurred across 4 bouts, which were all separated by 10 min rest periods. Follow-up experiments revealed that tapping frequency was still increased in consecutive bouts when rest periods were extended to 20 min. Besides, near-maximal muscle activation, followed by 5 min rest, did not affect the tapping frequency. In conclusion, freely chosen tapping frequency was increased in repeated bouts of tapping, which were separated by 10–20 min rest periods. The observed phenomenon is suggested to be termed repeated bout rate enhancement.

Isolated rheumatoid nodules: a diagnostic dilemma.

We present a 27-year-old male with multiple nonpainful soft tissue masses over several metacarpals, bilateral elbows, the left wrist, and both knees since the age of 4. Physical exam was significant for firm, nonmobile, nodular growths over the extensor surfaces of bilateral elbows and knees and on the 2nd and 5th metacarpal phalangeal joints. Laboratory studies revealed an unremarkable rheumatoid factor, negative ANA screening and normal joint radiographs. Differential diagnosis included subcutaneous granuloma annulare (SGA), seronegative rheumatoid nodule, and calcinosis cutis. Biopsy is the only method to distinguish benign rheumatoid nodules from SGA. This case illustrates the importance of biopsy in diagnosis, an awareness of the potential complications, and the need for good follow-up.

Mechanical stimulation enhances integration in an in vitro model of cartilage repair.

(1) To characterize the effects of mechanical stimulation on the integration of a tissue-engineered construct in terms of histology, biochemistry and biomechanical properties; (2) to identify whether cells of the implant or host tissue were critical to implant integration; and (3) to study cells believed to be involved in lateral integration of tissue-engineered cartilage to host cartilage. We hypothesized that mechanical stimulation would enhance the integration of the repair implant with host cartilage in an in vitro integration model. Articular cartilage was harvested from 6- to 9-month-old bovine metacarpal-phalangeal joints. Constructs composed of tissue-engineered cartilage implanted into host cartilage were placed in spinner bioreactors and maintained on a magnetic stir plate at either 0 (static control) or 90 (experimental) rotations per minute (RPM). The constructs from both the static and spinner bioreactors were harvested after either 2 or 4weeks of culture and evaluated histologically, biochemically, biomechanically and for gene expression. The extent and strength of integration between tissue-engineered cartilage and native cartilage improved significantly with both time and mechanical stimulation. Integration did not occur if the implant was not viable. The presence of stimulation led to a significant increase in collagen content in the integration zone between host and implant at 2weeks. The gene profile of cells in the integration zone differs from host cartilage demonstrating an increase in the expression of membrane type 1 matrix metalloproteinase (MT1-MMP), aggrecan and type II collagen. This study shows that the integration of in vitro tissue-engineered implants with host tissue improves with mechanical stimulation. The findings of this study suggests that consideration should be given to implementing early loading (mechanical stimulation) into future in vivo studies investigating the long-term viability and integration of tissue-engineered cartilage for the treatment of cartilage injuries. This could simply be done through the use of continuous passive motion (CPM) in the post-operative period or through a more complex and structured rehabilitation program with a gradual increase in forces across the joint over time.

Novel Equine Fetlock Points: Symmetry, Balance and New Acupoint Couplings

Transpositional placement of equine acupoints based upon human anatomy is taught in traditional Chinese veterinary medicine training programs throughout the world. There seems to be good evidence for such acupuncture point (acupoint) assignment on the axial and proximal appendicular body of horses. Distal acupoints in the feet, by contrast, are commonly described in anatomical positions that do not take into consideration the unique anatomy and function of the distal equine limb. The metacarpal-phalangeal joint (fetlock) is an area where Qi is concentrated. At least 2 clinically useful acupoints can be found each on the cranio-lateral and caudo-lateral and cranio-medial and caudo-medial thoracic and pelvic limbs, on either side of the suspensory ligament, proximal to the joint. Varying combinations of these 8 bilateral acupoints may also be used for Balancing Channels when treating multi-Channel pathology. Further, the fetlock acupoints may couple to open the Extraordinary Vessels better than transposed acupoints from humans. Lastly, the new proposed fetlock acupoints may also be a new form of a Yuan (Source) points.

Articular Chondroprogenitor Cells Maintain Chondrogenic Potential but Fail to Form a Functional Matrix When Implanted Into Muscles of SCID Mice.

ObjectiveArticular cartilage is a complex tissue comprising phenotypically distinct zones. Research has identified the presence of a progenitor cell population in the surface zone of immature articular cartilage. The aim of the present study was to determine the in vivo plasticity of articular cartilage progenitor.DesignChondropogenitor cells were isolated from bovine metacarpalphalangeal joints by differential adhesion to fibronectin. Cells were labeled with PKH26 and injected into the thigh muscle of severe-combined immunodeficient (SCID) mice. After 2 weeks, the muscles were dissected and cryosectioned. Sections were stained with safranin O and labeled for sox9 and collagen type II. Polymerase chain reaction analysis was carried out to determine plasticity for a number of tissue-specific markers. Full-depth chondrocytes acted as a control.ResultsFluorescent PKH26 labeled cells were detected after 2 weeks in all samples analyzed. A cartilage pellet was present after injection of freshly isolated chondrocytes. After injection with clonal and enriched populations of chondroprogenitors, no distinct pellet was detected, but diffuse cartilage nodules were found with regions of safranin O staining and Sox9. Low levels of collagen type II were also detected. Polymerase chain reaction analysis identified the presence of the endothelial cell marker PECAM-1 in one clonal cell line, demonstrating phenotypic plasticity into the phenotype of the surrounding host tissues.ConclusionsThe bovine articular cartilage progenitor cells were able to survive in vivo postimplantation, but failed to create a robust cartilage pellet, despite expressing sox9 and type II collagen. This suggests the cells require further signals for chondrogenic differentiation.

Ring injuries of the finger: long-term follow-up.

The purpose of this study was to report on the injury patterns and outcomes of a series of patients treated at our institution between the years 1983 and 2010 who were injured by rings worn on their finger. The series included typical ring avulsion injuries as well as all other injuries caused by rings. Retrospective chart review was conducted on 33 patients with ring injuries treated by the senior author and colleagues. Eight cases were classified as Urbaniak class I, 13 class II, and 12 class III. Satisfactory finger motion occurred with salvage of fingers in which no damage occurred to the proximal phalanx or flexor digitorum sublimus or profundus tendons. All patients with flexor tendon injury or proximal phalangeal fracture or both had loss of PIPJ motion and total active motion as compared to class II injuries without tendon and bone involvement. Four class III injuries were treated with replantation. One failed requiring revision amputation at the metacarpalphalangeal joint level due to ischemia. The remaining eight were treated by primary amputation. As a guideline to digit salvage with ring injuries, the authors propose accurately documenting and basing treatment on all injured structures. Particular attention should be given to fractures of the proximal phalanx and laceration of the flexor digitorum sublimus and profundus tendons, as injury to these structures led to significant loss in mobility of the finger in this series. While some current guidelines advise revascularization of class II ring avulsion injuries, our series suggests caution in anticipating good results with sublimus or profundus tendon laceration and proximal phalanx fracture. If the profundus tendon only is lacerated, particularly in zone I injuries, results of finger salvage may still be acceptable, but associated (distal interphalangeal joint) DIPJ injury may require K-wire stabilization and later fusion. Replantation in class III injuries, while possible, is warranted only in select situations (patient-specific and cultural factors).

Inflammatory ultrasound features show independent associations with progression of structural damage after over 2 years of follow-up in patients with hand osteoarthritis

ObjectiveTo study the development of inflammatory features and it's relation to structural damage over a 2.3-year period in patients with hand osteoarthritis (HOA).MethodsSynovial thickening, effusion and power Doppler signal (PDS)...

Giant pterosaurs and the limits of animal flight (13.3)

Pterosaurs appear to have had a particular propensity for the evolution of large size compared with other flying animals: at least eight genera of pterosaurs included species with wingspans in excess of 4 meters. I present a launch constraints model that accurately predicts size trends in pterosaurs. Azhdarchid pterosaurs evolved a suite of traits associated with improved terrestrial ability and rapid launch, including an expanded and curved deltopectoral crest, expanded coracoid flange, elongate metacarpal IV, and a reinforced fourth metacarpal‐phalangeal joint. This pattern explains why the largest pterosaurs were members of the Azhdarchidae. Most other “giant” pterosaurs were marine, and may have been more constrained in size than azhdarchids as a result of water launching requirements. Large marine pterosaurs, such as anhanguerids, tended to possess an expanded scapula, reinforced scapular‐notarial joint, warped deltopectoral crest, exceptionally broad wing pivot joint, expanded posterior brachial musculature, and reduced hind limbs. These traits are predicted as specializations to water launching. Pneumaticity, forelimb hypertrophy, and quadrupedal launch, combined with selection for low energy loitering and/or extended range, explains the repeated evolution of large size in pterosaurs.