PNPLA3 rs738409 I748M is associated with steatohepatitis in 434 non-obese subjects with hepatitis C

BACKGROUND

The PNPLA3/Adiponutrin rs738409 C/G single nucleotide polymorphism is associated with the severity of steatosis, steatohepatitis and fibrosis in patients with non-alcoholic fatty liver disease, as well as the severity of steatosis and fibrosis in patients with chronic hepatitis C (CHC).

AIM

To test in genotype 1(G1)-CHC patients, the putative association between the PNPLA3 variant and histological features of steatohepatitis, as well as their impact on the severity of fibrosis.

METHODS

Four hundred and thirty-four consecutively biopsied Caucasian G1-CHC patients were genotyped for PNPLA3 rs738409, its effect evaluated by using an additive model. Histological features of steatohepatitis in CHC were assessed using the Bedossa classification. Hepatic expression of PNPLA3 mRNA was evaluated in 63 patients.

RESULTS

The prevalence of steatohepatitis increased from 16.5% in patients with PNPLA3 CC, to 23.2% in CG and 29.2% in the GG genotype (P = 0.02). By multiple logistic regression, PNPLA3 genotype (OR 1.54, 95% CI 1.03-2.30, P = 0.03), together with age (OR 1.03, 95% CI 1.00-1.05, P = 0.02), BMI ≥ 30 (OR 2.06, 95% CI 1.04-4.10, P = 0.03) and homoeostasis model assessment (HOMA, OR 1.18, 95% CI 1.04-1.32, P = 0.006) were independently linked to steatohepatitis. When stratifying for obesity, PNPLA3 was associated with NASH in non-obese patients only (12.0% in CC vs. 18.3% in CG vs. 27.3% in GG, P = 0.01), including after correction for metabolic confounders (OR 2.06, 95% CI 1.26-3.36, P = 0.004). We showed an independent association between steatohepatitis (OR 2.05, 95% CI 1.05-4.02, P = 0.003) and severe fibrosis. Higher liver PNPLA3 mRNA was associated both with the severity of steatosis (adjusted P = 0.03) and steatohepatitis after adjusting for gender, age, BMI and HOMA (P = 0.002).

CONCLUSION

In patients with genotype 1 hepatitis C, the PNPLA3 G variant is associated with a higher risk of steatosis severity and steatohepatitis, particularly among non-obese subjects.

Long-term biomechanical outcomes after Achilles tendon ruptures

PURPOSE

The ideal treatment for Achilles tendon ruptures is still unknown. Biomechanical were correlated to radiological and clinical parameters to study outcomes.

METHODS

In this retrospective, assessor-blinded multi-centre cohort study, 52 patients with unilateral Achilles tendon rupture were assessed, each at least 3 years after injury. Patients underwent open surgery, percutaneous surgery or non-surgical treatment of Achilles tendon rupture. Both legs underwent plantar pressure distribution and isokinetic measures. Demographic parameters, maximum calf circumference (MCC) and clinical scores (American Orthopaedic Foot and Ankle Society, Achilles tendon rupture score, Hannover) were also evaluated. Complications were not assessed.

RESULTS

Peak plantar flexion torque (PPFT) was significantly weaker on the treated side compared to the untreated leg [80.4 ± 29.7 Nm (mean ± SD) vs. 92.1 ± 27.4 Nm, p < 0.0001]. PPFT and push-off force (POFF) were not different between treatment groups nor was there a leg difference in POFF alone. There was only a weak correlation of clinical scores and PPFT or POFF, respectively. MCC correlated significantly with both PPFT (R (2) = 0.21, p = 0.01) and POFF (R (2) = 0.29, p < 0.0001). POFF appeared to be a predictor of PPFT (R (2) = 0.31, p < 0.0001). Open surgery outperformed non-surgical treatment in terms of centre-of-pressure line (p = 0.007), torque per muscle volume (p = 0.04) and relative POFF per body weight (p = 0.02) and relative in side comparison (p = 0.03).

CONCLUSIONS

Clinical scores do not predict biomechanical outcomes. Clinically measured MCC is a good predictor of PPFT and POFF and can easily be used in clinical practice. Relative POFF in side comparison as well as per body weight favours surgical treatment.

[Contribution of arterial spin labeling to the diagnosis of sudden and transient neurological deficit]

MRI is the gold standard exploration for sudden transient neurological events. If diffusion MRI is negative, there may be a diagnostic doubt between transient ischemic attack and other causes of transient neurological deficit. We illustrate how sequence arterial spin labeling (ASL), which evaluates cerebral perfusion, contributes to the exploration of transient neurological events. An ASL sequence was performed in seven patients with a normal diffusion MRI explored for a transient deficit. Cortical hyperperfusion not systematized to an arterial territory was found in three and hypoperfusion systematized to an arterial territory in four. ASL helped guide early management of these patients.

Bulk effect of the deltoid muscle on the glenohumeral joint

Background

There remains controversy on the role of the deltoid on glenohumeral translations during basic and pitching motions. We thus studied the passive effect of the deltoid on the deltoid glenohumeral joint center (GHJC).

Methods

Six shoulders were tested using an automated mechanical system. A baseline motion pattern of the intact specimen was contrasted with glenohumeral translation after removal of the deltoid. Each condition was evaluated in abduction (ABD) and an abbreviated throwing motion (ATM) using retro-reflective, bone-embedded markers. The absolute trajectory and the area under the curve (AUC) for each motion were calculated and glenohumeral kinematics with respect to the GH translation were compared.

Results

The removal of the deltoid resulted in significant changes of the GH translation. During 30-60° of ABD, it resulted in a superior and more anterior GH translation, while in the 60-90° segment in a more inferior and medial GH translation. During 90-120°, the GH translation was medialized. In the pitching motion from maximum external rotation to 90° of external rotation (ER), the removal of the deltoid resulted in a more superior, anterior and lateral GH translation. Thus limits anterior translation in the abduction-external rotation position. In the remaining segments (90-80° and 80-45° of ER), it resulted in a lateralization of the GH translation.

Conclusions

Modelling the throwing shoulder, the deltoid has a significant influence on glenohumeral motion. Athletes with deltoid dysfunction and limited range of motion are at risk for injury due to the resulting change in their throwing mechanics.

The arthroscopic latarjet procedure for anterior shoulder instability: 5-year minimum follow-up

BACKGROUND

The arthroscopic Latarjet procedure combines the benefits of arthroscopic surgery with the low rate of recurrent instability associated with the Latarjet procedure. Only short-term outcomes after arthroscopic Latarjet procedure have been reported.

PURPOSE

To evaluate the rate of recurrent instability and patient outcomes a minimum of 5 years after stabilization performed with the arthroscopic Latarjet procedure.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent the arthroscopic Latarjet procedure before June 2008 completed a questionnaire to determine whether they had experienced a dislocation, subluxation, or further surgery. The patients also completed the Western Ontario Shoulder Instability Index (WOSI).

RESULTS

A total of 62 of 87 patients (64/89 shoulders) were contacted for follow-up. Mean follow-up time was 76.4 months (range, 61.2-100.7 months). No patients had reported a dislocation since their surgery. One patient reported having subluxations since the surgery. Thus, 1 patient (1.59%) had recurrent instability after the procedure. The mean ± standard deviation aggregate WOSI score was 90.6% ± 9.4%. Mean WOSI domain scores were as follows: Physical Symptoms, 90.1% ± 8.7%; Sports/Recreation/Work, 90.3% ± 12.9%; Lifestyle, 93.7% ± 9.8%; and Emotions, 88.7% ± 17.3%.

CONCLUSION

The rate of recurrent instability after arthroscopic Latarjet procedure is low in this series of patients with a minimum 5-year follow-up. Patient outcomes as measured by the WOSI are good.

Subacromial spacer placement for protection of rotator cuff repair

Rotator cuff repairs have a high failure rate proportional to the tear size. Various techniques have been described to improve the repair strength and failure rate. The described surgical technique uses a biodegradable subacromial balloon-shaped spacer (InSpace; OrthoSpace, Caesarea, Israel) that is implanted arthroscopically to protect our tendon repair. We describe the introduction technique and suggest some hints and tricks. The spacer is placed under direct vision in the subacromial space after the rotator cuff repair is finished. Correct placement is verified by moving the arm freely. The subacromial spacer may help to protect the rotator cuff repair by centering the humeral head and reducing friction between suture knots and the acromion. It may also help to flatten dog-ear formations.

The effect of supraspinatus tears on glenohumeral translations in passive pitching motion

BACKGROUND

Supraspinatus tears are common in pitchers. However, the effect of these tears on glenohumeral (GH) mechanics is incompletely understood.

PURPOSE/HYPOTHESIS

To describe the effect of supraspinatus tears and repairs on GH kinematics during an abbreviated throwing motion using the intact shoulder girdle. The hypothesis was that supraspinatus tears would lead to an increase of GH translation in the coronal plane and supraspinatus repairs would restore GH kinematics.

STUDY DESIGN

Controlled laboratory study.

METHODS

Six shoulders from 3 fresh-frozen cadavers were tested in a novel 7 degrees of freedom robotic testing system. Torsos were mounted and the wrist was pinned to an actuator mounted on an upper frame. After the deltoid was removed, the shoulders were studied during an abbreviated throwing motion (ATM) from maximum external rotation to the midcoronal plane to establish a baseline. The ATM was repeated after creation of a 1-cm supraspinatus tear, after creation of a 3-cm supraspinatus tear, and after repair with a transosseous equivalent (TOE) technique. Retroreflective bone markers and high-speed infrared cameras were used to measure GH kinematics and calculate the center of rotation of the GH joint (CORGH) instantaneously.

RESULTS

The 1- and 3-cm supraspinatus tears did not significantly alter GH translation. The TOE repair shifted the CORGH posteriorly, as evidenced by a significant decrease in the overall GH translation in all 3 planes (P = .003, .019, and .026, for x-y, y-z, and x-z planes, respectively).

CONCLUSION

In contrast to a TOE repair of the supraspinatus tendon, isolated supraspinatus tears did not perturb GH kinematics in this cadaveric model of the throwing shoulder.

CLINICAL RELEVANCE

In throwing athletes, treatment of rotator cuff tears should be addressed with caution to avoid an unintended alteration in GH kinematics due to overtightening of the tendon.

All-inside meniscal repair devices compared with their matched inside-out vertical mattress suture repair: introducing 10,000 and 100,000 loading cycles

BACKGROUND

All-inside arthroscopic meniscal repairs are favored by most clinicians because of their lower complication rate and decreased morbidity compared with inside-out techniques. Until now, only 1000 cycles have been used for biomechanical testing.

HYPOTHESIS

All-inside meniscal repairs will show inferior biomechanical response to cyclic loading (up to 100,000 cycles) and load-to-failure testing compared with inside-out suture controls.

STUDY DESIGN

Controlled laboratory study.

METHODS

Bucket-handle tears in 72 porcine menisci were repaired using the Omnispan and Fast-Fix 360 (all-inside devices) and Orthocord 2-0 and Ultrabraid 2-0 sutures (matched controls). Initial displacement, displacement after cyclic loading (100, 500, 1000, 2000, 5000, 10,000, and 100,000 cycles) between 5 and 20 N, ultimate load to failure, and mode of failure were recorded, as well as stiffness.

RESULTS

Initial displacement and displacement after cyclic loading were not different between the groups. The Omnispan repair demonstrated the highest load-to-failure force (mean ± SD, 151.3 ± 21.5 N) and was significantly stronger than all the other constructs (Orthocord 2-0, 105.5 ± 20.4 N; Ultrabraid 2-0, 93.4 ± 22.5 N; Fast-Fix 360, 76.6 ± 14.2 N) (P < .0001 for all). The Orthocord vertical inside-out mattress repair was significantly stronger than the Fast-Fix 360 repair (P = .003). The Omnispan (30.8 ± 3.5 N/mm) showed significantly higher stiffness compared with the Ultrabraid 2-0 (22.9 ± 6.9 N/mm, P < .0001) and Fast-Fix 360 (23.7 ± 3.9 N/mm, P = .001). The predominant mode of failure was suture failure.

CONCLUSION

All-inside meniscal devices show comparable biomechanical properties compared with inside-out suture repair in cyclic loading, even after 100,000 cycles.

CLINICAL RELEVANCE

Eight to 10 weeks of rehabilitation might not pose a problem for all repairs in this worst-case scenario.

Broca's area damage is necessary but not sufficient to induce after-effects of cathodal tDCS on the unaffected hemisphere in post-stroke aphasia

BACKGROUND

The inter-individual variability of behavioral effects after tDCS applied to the unaffected right hemisphere in stroke may be related to factors such as the lesion location.

OBJECTIVE/HYPOTHESIS

We investigated the effect of left Broca's area (BA) damage on picture naming in aphasic patients after cathodal tDCS applied over the right BA.

METHODS

We conducted a study using pre-interventional diffusion and resting state functional MRI (rsfMRI) and two cross-over tDCS sessions (TYPE: sham and cathodal) over the right homologous BA in aphasic stroke patients with ischemic lesions involving the left BA (BA+) or other left brain areas (BA-). Picture naming accuracy was assessed after each session. Inter-hemispheric (IH) functional balance was investigated via rsfMRI connectivity maps using the right BA as a seed. Probabilistic tractography was used to study the integrity of language white matter pathways.

RESULTS

tDCS had different effects on picture naming accuracy in BA+ and BA- patients (TYPE × GROUP interaction, F(1,19): 4.6, P: 0.04). All BA- patients except one did not respond to tDCS and demonstrated normal IH balance between the right and left BA when compared to healthy subjects. BA+ patients were improved by tDCS in 36% and had decreased level of functional IH balance. Improvement in picture naming after cathodal tDCS was associated with the integrity of the arcuate fasciculus in BA+ patients.

CONCLUSIONS

Behavioral effects of cathodal tDCS on the unaffected right hemisphere differ depending on whether BA and the arcuate fasciculus are damaged. Therefore, IH imbalance could be a direct consequence of anatomical lesions.

Immobilization in internal or external rotation does not change recurrence rates after traumatic anterior shoulder dislocation

BACKGROUND

The objective of this study was to systematically review and quantitatively synthesize the data on recurrence rates after shoulder immobilization in internal versus external rotation in first-time, traumatic shoulder dislocations.

MATERIALS AND METHODS

We performed a systematic search of the keywords "(((external rotation) OR internal rotation) AND immobilization) AND shoulder" in the online databases PubMed, EMBASE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and the Cochrane Library. Random-effects models were used to calculate the cumulatively pooled risk ratios (RRs) of recurrent shoulder dislocations. All analyses were also stratified by age.

RESULTS

We included 5 studies with a total of 471 patients (230 internal rotation and 241 external rotation) published between 2001 and 2011 in English. The pooled random-effects RR for recurrence of shoulder dislocations at all ages was 0.74 (95% confidence interval [CI], 0.44-1.27; P = .278). The RR was 0.70 (95% CI, 0.38 to 1.29; P = .250) for patients aged 30 years or younger and 0.78 (95% CI, 0.32 to 1.88; P = .579) for those aged older than 30 years.

CONCLUSION

The current best evidence does not support a relative effectiveness of immobilization in external rotation compared with internal rotation to avoid recurrent shoulder dislocations in patients with traumatic anterior shoulder dislocations.

Microstructural, densitometric and metabolic variations in bones from rats with normal or altered skeletal states

Background

High resolution μCT, and combined μPET/CT have emerged as non-invasive techniques to enhance or even replace dual energy X-ray absorptiometry (DXA) as the current preferred approach for fragility fracture risk assessment. The aim of this study was to assess the ability of µPET/CT imaging to differentiate changes in rat bone tissue density and microstructure induced by metabolic bone diseases more accurately than current available methods.

Methods

Thirty three rats were divided into three groups of control, ovariectomy and vitamin-D deficiency. At the conclusion of the study, animals were subjected to glucose (¹⁸FDG) and sodium fluoride (Na¹⁸F) PET/CT scanning. Then, specimens were subjected to µCT imaging and tensile mechanical testing.

Results

Compared to control, those allocated to ovariectomy and vitamin D deficiency groups showed 4% and 22% (significant) increase in ¹⁸FDG uptake values, respectively. DXA-based bone mineral density was higher in the vitamin D deficiency group when compared to the other groups (cortical bone), yet μCT-based apparent and mineral density results were not different between groups. DXA-based bone mineral density was lower in the ovariectomy group when compared to the other groups (cancellous bone); yet μCT-based mineral density results were not different between groups, and the μCT-based apparent density results were lower in the ovariectomy group compared to the other groups.

Conclusion

PET and micro-CT provide an accurate three-dimensional measurement of the changes in bone tissue mineral density, as well as microstructure for cortical and cancellous bone and metabolic activity. As osteomalacia is characterized by impaired bone mineralization, the use of densitometric analyses may lead to misinterpretation of the condition as osteoporosis. In contrast, µCT alone and in combination with the PET component certainly provides an accurate three-dimensional measurement of the changes in both bone tissue mineral density, as well as microstructure for cortical and cancellous bone and metabolic activity.

Preliminary evaluation of a robotic apparatus for the analysis of passive glenohumeral joint kinematics

Background

The shoulder has the greatest range of motion of any joint in the human body. This is due, in part, to the complex interplay between the glenohumeral (GH) joint and the scapulothoracic (ST) articulation. Currently, our ability to study shoulder kinematics is limited, because existing models isolate the GH joint and rely on manual manipulation to create motion, and have low reproducibility. Similarly, most established techniques track shoulder motion discontinuously with limited accuracy.

Methods

To overcome these problems, we have designed a novel system in which the shoulder girdle is studied intact, incorporating both GH and ST motions. In this system, highly reproducible trajectories are created using a robotic actuator to control the intact shoulder girdle. High-speed cameras are employed to track retroreflective bone markers continuously.

Results

We evaluated this automated system’s capacity to reproducibly capture GH translation in intact and pathologic shoulder conditions. A pair of shoulders (left and right) were tested during forward elevation at baseline, with a winged scapula, and after creation of a full thickness supraspinatus tear.

Discussion

The system detected differences in GH translations as small as 0.5 mm between different conditions. For each, three consecutive trials were performed and demonstrated high reproducibility and high precision.

The effect of simulated scapular winging on glenohumeral joint translations

HYPOTHESIS

In this study, we aim to test whether scapular winging results in a significant change in glenohumeral translation in the initial phase of the throwing motion.

METHODS

Six shoulders underwent an abbreviated throwing motion (ATM) from late cocking to the end of acceleration by use of a validated robotic system. The intact specimens were tested to establish a baseline. The position of the scapula was then affected to simulate scapular winging by placing a cylindrical wedge under the inferior angle of the scapula, and the ATM was performed again. For both conditions, the average glenohumeral translations and scapular rotations were plotted over time to calculate the area under the curve, as a representative of the overall glenohumeral translations and scapular rotations observed during the ATM.

RESULTS

Throughout the motion, the winged scapulae showed, on average, 7.7° more upward rotation, 1.6° more internal rotation, and 5.3° more anterior tipping as compared with the baseline. The scapular position relative to the hanging arm was significantly different between the baseline and scapular winging conditions in all arm positions, except for maximal external rotation and the neutral position. Comparing the area under the curve at baseline and with scapular winging indicated that scapular winging significantly increased anterior translation of the glenohumeral joint whereas translation in the superior/inferior and medial/lateral directions did not result in a change in translation.

DISCUSSION

These results may suggest a more important role of abnormalities in scapular position in predisposing throwing athletes to shoulder injuries of the anterior capsulolabral structures and consecutive glenohumeral instability.

Rates of radiolucency and loosening after total shoulder arthroplasty with pegged or keeled glenoid components

BACKGROUND

The objective of this study was to conduct a meta-analysis and cost-effectiveness analysis of the effect of glenoid design on radiolucency, loosening, and revision after total shoulder arthroplasty.

METHODS

We conducted a systematic review of PubMed, MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and CINAHL with use of a search for the terms arthroplasty AND shoulder AND (peg OR keel). Data on study design and on the end points of radiolucency, loosening, and revision were extracted independently and in duplicate. Random-effect models were used to calculate the pooled risk ratio and risk difference. The risk difference was used to estimate the number needed to treat (the number of individuals who would have to receive a pegged component to avoid one loosening or revision).

RESULTS

Eight studies with a total of 1460 patients (mean age, sixty-seven years) were included. The mean study quality was 1.75 points (95% confidence interval [CI], 1.26 to 2.24) on the 3-point modified Jadad scale. There was no significant difference in the risk of any radiolucency (risk ratio, 0.42; 95% CI, 0.12 to 1.42) or in the risk of severe radiolucency (risk ratio, 0.65; 95% CI, 0.23 to 1.82) between pegged and keeled components. The pooled risk ratio for revision was 0.27 (95% CI, 0.08 to 0.88) in favor of pegged components (p = 0.028). At a cost-effectiveness threshold of $50,000 per quality-adjusted life year, pegged components can be between $2325 and $40,920 more expensive than keeled components and still be cost-effective.

CONCLUSIONS

Our study produced evidence that pegged glenoid components were associated with a lower revision risk compared with keeled components. However, the difference was rather small and will therefore be most meaningful to high-volume shoulder arthroplasty centers. Because of the similarity between primary and secondary costs, pegged glenoid designs were more cost-effective than keeled glenoid designs.

The role of platelets in the treatment of Achilles tendon injuries

To systematically review the current in-vivo evidence for the use of platelet-concentrates (PRP) in the treatment of Achilles tendinopathy and Achilles tendon ruptures in animal models and human applications. A systematic search of PubMed, CINAHL, EMBASE, CCTR, and CDSR was performed for animal and human studies on the effect of platelet-concentrates in the treatment of Achilles tendinopathy and ruptures using the terms "Achilles tendon and platelet." The systematic search revealed a total of 149 papers. After excluding duplicates and cases of overlapping data, studies not focusing on in vivo evidence in terms of treatment or outcome, studies without any intervention, studies with unacceptable high attrition, one Chinese and one Swedish study, the remaining 14 manuscripts were included. The key finding of our study is evidence in support of a statistically significant effect of platelet concentrates in the treatment of Achilles tendon ruptures in vivo in animal models and human application, consistent with a medium to large sized effect. This effect is most likely attributable to fastened and enhanced scar tissue maturation. There was no evidence for a beneficial effect of platelets in Achilles tendinopathy.

Re-excision Rates and Local Recurrence in Breast Cancer Patients Undergoing Breast Conserving Therapy

Background: Controversy continues over the impact of re-excision (RE) on local recurrence (LR) in patients with invasive breast cancer. Patients and Methods: We investigated factors which could effect RE rates in patients undergoing breast-conserving or oncoplastic surgery. Between 2000 and 2003, 489 patients with stage pT1-pT2 or pN0/1 tumors were evaluated. 74 patients fulfilled the inclusion criteria. Patients were categorized into 3 groups: no RE (n = 25), RE during primary surgery (n = 28), and RE performed during secondary or even tertiary procedure (n = 21). All tumor slides were re-evaluated by a pathologist specializing in breast cancer. Results: Mean follow-up was 70 months with an overall LR rate of 4.1 %. Binary logistic regression revealed no tumor-specific risk factors for RE. There was no LR in the group of patients who did not have RE. There was one case of LR in the group of patients who had RE during primary surgery. Two cases of LR were observed in the group of patients who had two or more surgical procedures. Conclusion: New risk factors for increased RE rates were not observed, reflecting the inconsistent data on risk factors for RE. However, breast cancers should be excised in a single procedure and oncoplastic procedures should be considered.

Physiological Achilles tendon length and its relation to tibia length

OBJECTIVE

The optimal intraoperative Achilles tendon length (ATL) adjustment is crucial for the physiological functioning of the musculotendinous unit. To date, the resting ATL and its relation to tibia length (TL) have never been defined in healthy subjects. We thus performed metric measurements of the ATL and TL.

DESIGN

Case series.

SETTING

Clinical and radiological measurements.

PARTICIPANTS

Fifty-two subjects placed in a 3-T magnetic resonance imaging with the ankle in neutral position.

MAIN OUTCOME MEASURES

Unilateral ATL measured from the calcaneal insertion to the beginning of the medial gastrocnemius muscle, TL measured from the intercondylar eminence to the center of the ankle, and qualitative tendon parameters in T2 sequences and human parameters were noted; results were correlated with age, gender, body height, weight, body mass index (BMI), and side of the AT and TL.

RESULTS

The mean ATL was 180.6 ± 25.0 mm and the mean TL was 371.9 ± 25.4 mm with an ATL:TL ratio of 49 ± 5%. Achilles tendon length correlated significantly with body height (R = 38%, P < 0.0001) and with TL (R = 41%, P < 0.0001) but did not correlate with age, BMI, and side of the AT. Tibia length correlated with body height (R = 83%, P < 0.0001) and in multivariate linear regression, TL was the only independent predictor of ATL following the algorithm, ATL (mm) = 0.6 × TL (mm) - 53 (R = 41%).

CONCLUSIONS

We defined a new way to measure the ATL in a consistent way in healthy subjects and showed correlations between ATL, TL and body height and defined an algorithm of ATL based on TL. The ATL and the ATL-algorithm might be important in patients with impaired tendons such as AT ruptures.

Design and manufacture of a novel system to simulate the biomechanics of basic and pitching shoulder motion

Objectives

Cadaveric models of the shoulder evaluate discrete motion segments using the glenohumeral joint in isolation over a defined trajectory. The aim of this study was to design, manufacture and validate a robotic system to accurately create three-dimensional movement of the upper body and capture it using high-speed motion cameras.

Methods

In particular, we intended to use the robotic system to simulate the normal throwing motion in an intact cadaver. The robotic system consists of a lower frame (to move the torso) and an upper frame (to move an arm) using seven actuators. The actuators accurately reproduced planned trajectories. The marker setup used for motion capture was able to determine the six degrees of freedom of all involved joints during the planned motion of the end effector.

Results

The testing system demonstrated high precision and accuracy based on the expected versus observed displacements of individual axes. The maximum coefficient of variation for displacement of unloaded axes was less than 0.5% for all axes. The expected and observed actual displacements had a high level of correlation with coefficients of determination of 1.0 for all axes.

Conclusions

Given that this system can accurately simulate and track simple and complex motion, there is a new opportunity to study kinematics of the shoulder under normal and pathological conditions in a cadaveric shoulder model.

Initial Achilles tendon repair strength--synthesized biomechanical data from 196 cadaver repairs

PURPOSE

The study aim was to describe what kind of operative technique performs best with respect to initial strength after the surgical repair of acute Achilles tendon ruptures.

METHODS

We performed a systematic search of the keywords "Achilles tendon AND (suture strength OR biomechanics) AND (cadaver NOT animal)" in the online databases PubMed, EMBASE, CINAHL, and the Cochrane Library. We included studies that employed open, mini-open, or percutaneous Achilles tendon repair in human cadavers, and assessed some measure of tensile strength as a primary outcome.

RESULTS

Our search produced 11 relevant papers reporting results for Kessler, Bunnell, and Krackow sutures in open repair, as well as the Achillon device, the Ma-Griffith repair technique, the triple bundle technique and the "giftbox" technique. The weighted tensile strengths ranged from 81 to 453 N (mean 222.7 N) with the Triple Bundle technique in combination with # 2 Ethibond performing best with a mean of 453 N.

CONCLUSIONS

Due to the small sample sizes, different study designs, and heterogeneity of strength measurement techniques, definite recommendations on surgical technique cannot be made but presented information might help in the decision making process for foot and ankle surgeons.