A Bony Mallet Thumb with Interposition of the Nail Plate

Thumb extensor injuries and bony avulsion in the distal phalanx of the thumb are rare compared with other fingers. The most reported complications are infection, nail deformity, joint incongruity, implant failure, recurrent flexion deformity, and residual pain. This report presents a case of 30-year-old man suffering from an injury in the left thumb distal phalanx with a displaced comminuted intra-articular fracture of the distal phalanx of the left thumb. The nail plate was interposed between the dorsal and palmar fragments. The interposition of the nail plate in the bony mallet thumb has not been described before. Surgical treatment and fixation with a 2-mm miniscrew resulted in successful treatment. Clinical suspicion of this complication is of great importance and can affect treatment outcomes.

Genetic dissection of canine hip dysplasia phenotypes and osteoarthritis reveals three novel loci

Background Hip dysplasia and osteoarthritis continue to be prevalent problems in veterinary and human medicine. Canine hip dysplasia is particularly problematic as it massively affects several large-sized breeds and can cause a severe impairment of the quality of life. In Finland, the complex condition is categorized to five classes from normal to severe dysplasia, but the categorization includes several sub-traits: congruity of the joint, Norberg angle, subluxation degree of the joint, shape and depth of the acetabulum, and osteoarthritis. Hip dysplasia and osteoarthritis have been proposed to have separate genetic etiologies. Results Using Fédération Cynologique Internationale -standardized ventrodorsal radiographs, German shepherds were rigorously phenotyped for osteoarthritis, and for joint incongruity by Norberg angle and femoral head center position in relation to dorsal acetabular edge. The affected dogs were categorized into mild, moderate and severe dysplastic phenotypes using official hip scores. Three different genome-wide significant loci were uncovered. The strongest candidate genes for hip joint incongruity were noggin (NOG), a bone and joint developmental gene on chromosome 9, and nanos C2HC-type zinc finger 1 (NANOS1), a regulator of matrix metalloproteinase 14 (MMP14) on chromosome 28. Osteoarthritis mapped to a long intergenic region on chromosome 1, between genes encoding for NADPH oxidase 3 (NOX3), an intriguing candidate for articular cartilage degradation, and AT-rich interactive domain 1B (ARID1B) that has been previously linked to joint laxity. Conclusions Our findings highlight the complexity of canine hip dysplasia phenotypes. In particular, the results of this study point to the potential involvement of specific and partially distinct loci and genes or pathways in the development of incongruity, mild dysplasia, moderate-to-severe dysplasia and osteoarthritis of canine hip joints. Further studies should unravel the unique and common mechanisms for the various sub-traits.

Polar Histograms of Curvature for Quantifying Skeletal Joint Shape and Congruence

The effect of articular joint shape and congruence on kinematics, contact stress, and the natural progression of joint disease continues to be a topic of interest in the orthopedic biomechanics literature. Currently, the most widely used metrics of assessing skeletal joint shape and congruence are based on average principal curvatures across the articular surfaces. Here we propose a method for comparing articular joint shape and quantifying joint congruence based on three-dimensional (3D) histograms of curvature—shape descriptors that preserve spatial information. Illustrated by experimental results from the trapeziometacarpal joint, this method could help unveil the interrelations between joint shape and function and provide much needed insight for the high incidence of osteoarthritis (OA)—a mechanically mediated disease whose onset has been hypothesized to be precipitated by joint incongruity.

Static monolateral external fixation for the Rolando fracture: a simple solution for a complex fracture

INTRODUCTION Rolando fractures are often difficult to manage because of their inherent instability. We describe a simple technique for the treatment of this fracture using the principle of ligamentotaxis, with a static, two-pin external fixator spanning the trapeziometacarpal joint, and present the results of a single-surgeon case series. METHODS Eight consecutive patients (mean age: 32.8 years) with Rolando fractures were treated using a Hoffmann II® Micro small bone external fixator using blunt ended 2.0mm half pins, inserted into the trapezium and diaphysis of the first metacarpal. Functional outcome was assessed with the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score at a mean time of 2.7 years following the fracture (range: 4 months – 6.0 years). The mean time to frame removal was 28 days. RESULTS There were three cases of superficial pin site infection. Follow-up x-rays at four months did not demonstrate significant joint incongruity or malunion in any case. The mean QuickDASH score was 7.95 and all patients returned to their previous levels of activity. CONCLUSIONS Although external fixation risks pin site infection, the results of this study support the use of spanning trapeziometacarpal external fixation for Rolando fractures as it reliably gives excellent functional outcomes.

Traumatic fragmented medial coronoid process in a Chihuahua

SummaryFragmented medial coronoid process (FMCP) is a disease process that has not previously been reported in toy-breed dogs. This report describes a presumptive case of FMCP in a 14-month-old Chihuahua that was presented for evaluation approximately four weeks following acute onset of moderate lameness in the left forelimb. Definitive diagnosis of a fragmented medial coronoid process was based upon computed tomography (CT) scan. A CT scan also demonstrated moderate joint incongruity in the affected elbow. Surgical removal of the fragment and subtotal coronoidectomy were performed via a medial arthrotomy. An ulnar ostectomy was also performed to address joint incongruity. Histology of specimens removed at surgery did not demonstrate evidence of microdamage as characteristic of FMCP in large breed dogs, and instead, suggested that the fracture was acute and traumatic in nature. Rapid return to function was observed following surgery.

Transverse Loaded Pronosupination Test

A new test to evaluate the ability of the distal radioulnar joint to sustain transverse loads while the forearm rotates from pronation to supination is described. Both arms were tested in 100 normal volunteers. The average weight-bearing capability of the normal unsupported forearm was 5.07 kg, equating to a force of 49.8 N. The test may be useful in the assessment of pathological conditions involving weakness of the forearm rotator muscles, with or without joint incongruity, as well as being an indirect way to assess the load-bearing capacity of radioulnar implants.

CORRECTIVE OSTEOTOMY FOR INTRA-ARTICULAR MALUNION OF THE SIGMOID NOTCH OF THE DISTAL PART OF THE RADIUS: A CASE REPORT

Joint incongruity at radiocarpal joint is a common complication of the distal radius fracture, and has received much attention and study. However, the problem and outcome of treatment of intra-articular incongruity at the sigmoid notch after distal radius fracture is rarely reported. We describe a patient with deformity of the distal radioulnar joint, and impairment of supination after distal radius fracture. The evaluation of the distal radioulnar joint revealed the absence of degenerative arthritis and malunion of the sigmoid notch of the distal radius with a prominent volar lip limiting supination. We present a method of corrective osteotomy for the malunited sigmoid notch of the distal radius, to correct the incongruity of the distal radioulnar joint and restore supination.