Recently, Bomze et al. introduced a sparse conic relaxation of the scenario problem of a two stage stochastic version of the standard quadratic optimization problem. When compared numerically to ...Burer’s classical reformulation, the authors showed that there seems to be almost no difference in terms of solution quality, whereas the solution time can differ by orders of magnitudes. While the authors did find a very limited special case, for which Burer’s reformulation and their relaxation are equivalent, no satisfying explanation for the high quality of their bound was given. This article aims at shedding more light on this phenomenon and give a more thorough theoretical account of its inner workings. We argue that the quality of the outer approximation cannot be explained by traditional results on sparse conic relaxations based on positive semidenifnite or completely positive matrix completion, which require certain sparsity patterns characterized by chordal and block clique graphs respectively, and put certain restrictions on the type of conic constraint they seek to sparsify. In an effort to develop an alternative approach, we will provide a new type of convex reformulation of a large class of stochastic quadratically constrained quadratic optimization problems that is similar to Burer’s reformulation, but lifts the variables into a comparatively lower dimensional space. The reformulation rests on a generalization of the set-completely positive matrix cone. This cone can then be approximated via inner and outer approximations in order to obtain upper and lower bounds, which potentially close the optimality gap, and hence can give a certificate of exactness for these sparse reformulations outside of traditional, known sufficient conditions. Finally, we provide some numerical experiments, where we asses the quality of the inner and outer approximations, thereby showing that the approximations may indeed close the optimality gap in interesting cases.
Introduction
The aim of our study was the assessment of the mid-term outcome of patients treated with a pediculated extensor retinaculum flap for extensor carpi ulnaris (ECU) tendon subluxation ...including postoperative tendon stability control.
Materials and methods
Twelve patients treated with an extensor retinaculum flap for symptomatic ECU tendon instability were retrospectively evaluated. Follow-up examinations included functional and radiologic assessment. The range of motion, grip strength, DASH score, PRWE score, Krimmer score and subjective satisfaction were recorded. A rotation-movie MRI was conducted before and after surgery to visualize tendon displacement.
Results
Wrist extension was 65.8° (SD 10.0°), flexion 64.2° (SD 12.2°), radial deviation 15.8° (SD 6.0°), ulnar deviation 32.1° (SD 7.2°), pronation 82.5° (SD 9.4°) and supination 85.0° (SD 9.0°). Mean grip strength was 30.5 kg (SD 8.9 kg). Six patients presented an excellent, four a good, one a fair and one a poor result on the Krimmer score. The DASH and PRWE scores showed a mean of 24.2 (SD 25.1) and 32.2 (SD 29.4) points.
MRI showed a dislocation (
n
= 7) or subluxation (
n
= 5) of the ECU tendon preoperatively. Five patients showed an unchanged displacement pattern postoperatively.
Conclusion
The pediculated extensor retinaculum flap as a treatment for a symptomatic ECU instability shows good to excellent results and a high subjective satisfaction independent of postoperative ECU tendon displacement
Hand-transplantation and improvements in the field of prostheses opened new frontiers in restoring hand function in below-elbow amputees. Both concepts aim at restoring reliable hand function, ...however, the indications, advantages and limitations for each treatment must be carefully considered depending on level and extent of amputation. Here we report our findings of a multi-center cohort study comparing hand function and quality-of-life of people with transplanted versus prosthetic hands.
Hand function in amputees with either transplant or prostheses was tested with Action Research Arm Test (ARAT), Southampton Hand Assessment Procedure (SHAP) and the Disabilities of the Arm, Shoulder and Hand measure (DASH). Quality-of-life was compared with the Short-Form 36 (SF-36).
Transplanted patients (n = 5) achieved a mean ARAT score of 40.86 ± 8.07 and an average SHAP score of 75.00 ± 11.06. Prosthetic patients (n = 7) achieved a mean ARAT score of 39.00 ± 3.61 and an average SHAP score of 75.43 ± 10.81. There was no significant difference between transplanted and prosthetic hands in ARAT, SHAP or DASH. While quality-of-life metrics were equivocal for four scales of the SF-36, transplanted patients reported significantly higher scores in "role-physical" (p = 0.006), "vitality" (p = 0.008), "role-emotional" (p = 0.035) and "mental-health" (p = 0.003).
The indications for hand transplantation or prosthetic fitting in below-elbow amputees require careful consideration. As functional outcomes were not significantly different between groups, patient's best interests and the route of least harm should guide treatment. Due to the immunosuppressive side-effects, the indication for allotransplantation must still be restrictive, the best being bilateral amputees.
To compare final functional and radiographic outcomes of closed reduction and casting (CAST) with open reduction and internal fixation (ORIF) with palmar locking plate for unstable Colles type distal ...radius fractures (DRFs) in low-demand patients older than 70 years.
Retrospective, clinical study.
Level 1 university trauma center.
Over a mean period of 4 years and 7 months, 130 consecutive patients older than 70 years were treated for an unstable dorsally displaced DRF of which 114 or 87% were followed for 1 year or longer.
ORIF (n = 53) using volar locking plate or closed reduction and casting (n = 61).
Objective and subjective functional results (active range of motion; grip strength; disabilities of the arm, shoulder and hand (DASH) score; patient-rated wrist evaluation (PRWE) score; visual analog scale; and Green and O'Brien score) and radiographic assessment (dorsal tilt, radial inclination, radial shortening, fracture union, and posttraumatic arthritis) were assessed.
At final follow-up, there was no significant difference between the 2 groups for mean ranges of motion, grip strength, DASH score, PRWE score, and Green and O'Brien score. Pain level was significantly less for the patients in the CAST group. An obvious clinical deformity was present in 77% of cast group and none in the ORIF group. At final follow-up, in the ORIF group, there was a mean loss of dorsal tilt of 1.3 degrees, radial inclination of 0.3 degrees, and radial length of 0.5 mm compared with the postoperative measurements. No primary acceptable reduction was achieved in 44% of the CAST group. At final follow-up, in the CAST group, dorsal tilt, radial inclination, and radial shortening averaged -24.4 +/- 12 degrees, 19.2 +/- 6.5 degrees, and +3.9 +/- 2.7 mm, respectively. Malunion occurred in 89% primarily reduced fractures. Dorsal tilt, radial inclination, and radial shortening were significantly better in the ORIF group.
Radiographic results (dorsal tilt, radial inclination, and radial shortening) after unstable dorsally displaced DRFs are significantly better in patients treated by ORIF using a volar fixed-angle plate rather than those treated by cast immobilization (P < 0.05). At a mean follow-up time of 4 years and 7 months, the clinical outcomes of active range of motion, the PRWE, DASH, and Green and O'Brien scores do not differ between the 2 methods of treatment. The pain level was significantly less in the CAST group (P < 0.05), and this group experienced no complications. There was no difference between the subjective and functional outcomes for the surgical and the nonsurgical treatments in a cohort of patients older than 70 years. Unsatisfactory radiographic outcome in older patients does not necessarily translate into unsatisfactory functional outcome. Nonoperative treatment may be the preferred method of treatment in this age group.
Objective
To evaluate the accuracy of two different sonographic median nerve measurement calculations in predicting carpal tunnel syndrome (CTS) severity in a study population with clinically and ...electrophysiologically confirmed CTS.
Methods
643 wrists of 427 patients (325 females and 102 males, age range: 17–90 years, mean ± SD: 57.9 ± 14.7) were included with CTS diagnosis based on clinical and nerve conduction studies (NCS). Cross-sectional area (CSA) measurement of the median nerve was performed at the carpal tunnel level (CSAc) and at the pronator quadratus muscle level (CSAp). Two parameters were calculated: delta (∆-CSA), which is the difference between proximal and distal measurements, and ratio (R-CSA), calculated by dividing distal over proximal measurements.
Results
Patients were classified into mild, moderate and severe CTS based upon NCS. The mean ∆-CSA (4.2 ± 2.6, 6.95 ± 2.2 and 10.7 ± 4.9 mm
2
) and mean R-CSA (1.5 ± 0.4, 1.95 ± 0.4 and 2.4 ± 0.7) values were significantly different between all groups (
p
< 0.001). Optimal cut-off values for ∆-CSA and R-CSA were 6 mm
2
and 1.7, respectively, to distinguish mild from moderate disease, and 9 mm
2
and 2.2, respectively, to distinguish moderate from severe disease.
Conclusion
Threshold values for the calculated sonographic parameters ∆-CSA and R-CSA are useful in predicting CTS severity compared to NCS.
Key Points
•
Two proposed parameters were calculated (∆-CSA, R-CSA) and compared to NCS
.
•
A defined sonoanatomical proximal landmark was used for the calculation
.
•
Both parameters showed ability to detect CTS severity comparable to NCS
.
•
Cut-off values could be determined for both parameters
.
To evaluate the accuracy of ultrasonography (US) in the diagnosis of carpal tunnel syndrome (CTS) in patients with a bifid median nerve on the basis of cross-sectional area (CSA) measurements of the ...median nerve at the level of the carpal tunnel (CSAc), with additional measurements obtained more proximally (CSAp) at the level of the pronator quadratus muscle.
This HIPAA-compliant study was approved by the local institutional review board; informed oral and written consent were obtained. Fifty-three wrists in 49 consecutive patients with a bifid median nerve and CTS symptoms and 28 wrists in 27 healthy volunteers with a bifid median nerve were examined by using US. Two independent US examiners who were blinded to prior test results measured median nerve CSA at two levels, CSAc and CSAp. The difference between CSAc and CSAp (ΔCSA) was calculated for each wrist. Receiver operating characteristic (ROC) analysis was performed.
The study population included 17 men and 32 women (mean age, 55.1 years; age range, 24-78 years). The control population included 13 men and 14 women (mean age, 52.6 years; age range, 24-86 years). Mean CSAc was approximately 5 mm(2) greater in patients with CTS than in healthy volunteers (P < .0001), while mean ΔCSA was 5.8-5.9 mm(2) greater in patients with CTS (P < .0001). A CSAc threshold of 12 mm(2) provided sensitivity and specificity of 84.9% and 46.5%, respectively, while a ΔCSA threshold of 4 mm(2) provided sensitivity and specificity of 92.5% and 94.6%, respectively. ROC analysis demonstrated a significant advantage of ΔCSA (area under ROC curve A(z) = 0.95-0.96) compared with CSAc (A(z) = 0.84-0.85) for the diagnosis of CTS (P < .003).
The use of a ΔCSA parameter improves the diagnostic accuracy of US for the presence of CTS in patients with a bifid median nerve.
Introduction
Since March 2011, the microbial collagenase of
Clostridium histolyticum (
Xiapex®, Swedish Orphan Biovitrum AB, Stockholm, Sweden) has become available in the European Union for ...treatment of Dupuytren’s disease. The purpose of this study was to evaluate potential safety risks of Xiapex® and to contribute to a better understanding for its use.
Methods
A prospective, non-interventional, observational study using Xiapex® for Dupuytren’s disease named XIANIS was conducted between 1.10.2011 and 01.10.2017. Treatment was conducted in accordance to the manufacturer information. Patients were invited for follow-up after 1 week, 1 month, 3 months and 1 year. Demographic data, treatment data, pain levels, anaesthetic application during passive manipulation, subjective function improvement, subjective satisfaction and adverse events were recorded.
Results
788 patients with 814 treatments were included who suffered from Dupuytren’s contracture for a mean of 64 months. The metacarpophalangeal joint was affected in 57% of cases and the PIP joint in 40.8% with a mean contracture of 39° and 56°, respectively. A change in the contracture down to 0°–5° was reported in 66.5% of cases, while 25.5% achieved a partial improvement. The pain during the injection was rated 4.5 and 3.3 during passive manipulation. Adverse events were reported in the majority of treated patients with skin tears being one main common event (26%). Further adverse outcomes were bleeding/hematoma, joint swelling, injection-site swelling, pressure sensitivity, erythema, injection-site pain, peripheral edema, blood blisters, blisters, painless lymphadenopathy, painful lymphadenopathy, axillary pain, arthralgia and sensory abnormality. There were no reported tendon ruptures, anaphylactic reactions or ligament injuries. On 1-year follow-up, 29% showed an increased contracture of a mean of 24° with the need for surgical treatment in 2% of patients. 74% of patients were very satisfied and 72% showed a high functional improvement.
Conclusion
The injectable collagenase
Clostridium histolyticum
(Xiapex®) proved to be effective and safe in patients with Dupuytren’s disease. Minor adverse events disappeared within 30 days and the need for surgical treatment within 1 year was very low (2%). No major complications or rare side effects were seen in this prospective observational study.
We sought to assess vascularity in wrist tenosynovitis by using power Doppler ultrasound (PDUS) and to compare detection of intra- and peritendinous vascularity with that of contrast-enhanced ...grey-scale ultrasound (CEUS).
Twenty-six tendons of 24 patients (nine men, 15 women; mean age ± SD, 54.4 ± 11.8 years) with a clinical diagnosis of tenosynovitis were examined with B-mode ultrasonography, PDUS, and CEUS by using a second-generation contrast agent, SonoVue (Bracco Diagnostics, Milan, Italy) and a low-mechanical-index ultrasound technique. Thickness of synovitis, extent of vascularized pannus, intensity of peritendinous vascularisation, and detection of intratendinous vessels was incorporated in a 3-score grading system (grade 0 to 2). Interobserver variability was calculated.
With CEUS, a significantly greater extent of vascularity could be detected than by using PDUS (P < 0.001). In terms of peri- and intratendinous vessels, CEUS was significantly more sensitive in the detection of vascularization compared with PDUS (P < 0.001). No significant correlation between synovial thickening and extent of vascularity could be found (P = 0.089 to 0.097). Interobserver reliability was calculated to be excellent when evaluating the grading score (κ = 0.811 to 1.00).
CEUS is a promising tool to detect tendon vascularity with higher sensitivity than PDUS by improved detection of intra- and peritendinous vascularity.
Objectives
To assess the diagnostic performance of median nerve (MN) flip-angle measurements, deformation during wrist flexion transit deformation coefficient (TDC), during compression compression ...deformation coefficient (CDC) and fascicular freedom to potentially identify fibrotic MN changes in patients with carpal tunnel syndrome (CTS).
Methods
This prospective study was performed with institutional review board approval; all participants provided oral and written informed consent. Wrists in 21 healthy participants and 29 patients with CTS were examined by ultrasound. MN movement during wrist flexion, MN deformation during transition over the flexor tendons (TDC) and during controlled compression (CDC) as well as fascicular freedom were assessed. Diagnostic properties of these parameters were calculated and compared to clinical findings and cross-section area measurements (ΔCSA).
Results
Low flip angles were associated with high ΔCSA at a receiver-operator characteristics area under the curve (AUC) of 0.62 (0.51-0.74). TDC AUC, 0.83 (0.73-0.92), 76.3% (59.8-88.6%) sensitivity, 88.5% (76.6-95.7%) specificity, restricted fascicular movement AUC, 0.86 (0.78-0.94), 89.5% (75.2-97.1%) sensitivity, 80.8% (67.5-90.4%) specificity and compression-based CDC AUC, 0.97 (0.94-1.00), 82.1% (66.5-92.5%) sensitivity, 94.2% (84.1-98.8%) specificity demonstrated substantial diagnostic power (95% confidence intervals
in parentheses
).
Conclusions
Fascicular mobility, TDC and CDC show substantial diagnostic power and may offer insights into the underlying pathophysiology of CTS.
Key Points
• Dynamic ultrasonography during wrist flexion and compression enables median nerve deformability assessment.
• Overall, reduced median nerve deformability is highly indicative of CTS.
• Median nerve compressibility shows higher diagnostic power than conventional cross-section area measurements.
PDF
