Titanium-Coated Polyetheretherketone Cages Vs Full Titanium Cages for Stand-Alone 1- or 2-Level Anterior Cervical Discectomy and Fusion: A Comparative Study.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) for the surgical treatment of cervical degenerative disease often includes an intervertebral cage, which restores disc height and lordosis while promoting fusion . Cage materials include titanium (TTN) or polyetheretherketone (PEEK). Controversy in material selection stems from higher fusion rates with TNN, despite a higher subsidence rate, while PEEK cages demonstrate superior preservation of interspace height. Combining the advantages of both materials, TTN-coated PEEK (TCPEEK) cages were developed, featuring a PEEK core with similar stiffness to the bone, enveloped with a TTN coat, improving osteointegration. However, the potential superiority of TCPEEK over TTN cages has not been investigated. This study aimed to compare clinical and radiographic outcomes following single- or double-level ACDF using either TTN or TCPEEK cages. METHODS: This retrospective single-center study included patients undergoing single- or double-level ACDF between 2017 and 2019. Clinical outcomes included the Neck Disability Index and revision surgery incidence. Radiographic parameters included cervical and segmental lordosis, C2 to C7 sagittal vertical axis, fusion, subsidence, and adjacent segment degeneration at a minimum 12-month follow-up. RESULTS: A total of 45 patients (16 TTN; 29 TCPEEK) and 58 cervical levels (21 TTN; 37 TCPEEK) were included. Both cages significantly improved Neck Disability Index scores (TTN -10.0; TCPEEK -14.1) without significant differences. Two single-level TCPEEK patients required revision surgery due to non-union. In the radiological assessments, no significant difference was found for subsidence rates (TTN 52.4%; TCPEEK 56.8%), adjacent segment degeneration, cervical and segmental lordosis, and changes in C2 to C7 sagittal vertical axis. Though not statistically significant, fusion rates trended slightly higher with TTN (90.5%) vs TCPEEK cages (86.5%). CONCLUSION: TTN and TCPEEK cages achieve satisfactory clinical and radiological outcomes in single- or double-level ACDF. This finding suggests that the choice between them can be based on other factors, such as surgeon preference or availability, rather than specific material properties. CLINICAL RELEVANCE: This study found that the selection of ACDF cage material did not affect clinical outcomes.

Second Metatarsal Length and Transfer Ulcers After First Metatarsal Amputation in Diabetic Foot Infections.

BACKGROUND: Plantar transfer ulcers (TUs) underneath the second metatarsal head are frequent after first metatarsal ray amputations due to diabetic foot infections. Whether the second metatarsal length (2ML) is associated with TU occurrence in these patients is unclear. This study evaluated whether 2ML is associated with TU occurrence after first-ray amputations and whether ulcer-free survival is shorter in patients with "excess" 2ML. METHODS: Forty-two patients with a mean age of 67 (range 33-93) years, diabetes, and first metatarsal ray amputation (first amputation at the affected foot) were included. Two independent readers measured the 2ML using the Coughlin method. A protrusion of more than 4.0 mm of the second metatarsal was defined as "excess" 2ML. The effect of 2ML on ulcer occurrence was analyzed using a multivariate Cox regression model. A Kaplan-Meier curve for TU-free survival was constructed comparing the 2 groups of "normal" (n = 21) and "excess" 2ML (n = 21). RESULTS: Interrater reliability was excellent. TUs underneath the second metatarsal occurred in 15 (36%) patients. In agreement with our hypothesis, 2ML was nonsignificantly different in patients with TUs, recording a mean of 5.3 (SD 2.5) mm, compared to patients without 4.0 (SD 2.3) mm (hazard ratio [HR] 1.12, 95% CI 0.89-1.41), whereas insulin dependence was associated with ulcer occurrence (HR 0.33, 95% CI 0.11-0.99). CONCLUSION: In our relatively small study population with a cutoff level of 4 mm for excess 2ML, ulcer-free survival was similar in patients with "normal" and "excess" 2ML. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Anterolateral Acromioplasty Reduces Gliding Resistance Between the Supraspinatus Tendon and the Coracoacromial Arch in a Cadaveric Model.

Purpose: To investigate the gliding resistance dynamics between the supraspinatus (SSP) tendon and the coracoacromial arch, both before and after subacromial decompression (anterolateral acromioplasty) and acromion resection (acromionectomy). Methods: Using 4 fresh-frozen cadaveric shoulders, acromion shapes were classified (2 type I and 2 type III according to Bigliani). Subacromial bursa and coracoacromial ligament maintenance replicated physiologic sliding conditions. Gliding resistance was measured during glenohumeral abduction (0° to 60°) in internal rotation (IR) and external rotation (ER). Peak gliding resistance between the SSP tendon and the coracoacromial arch was determined and compared between intact, anterolateral acromioplasty, and acromionectomy. Results: Peak SSP gliding resistance during abduction in an intact shoulder was significantly higher in IR than in ER (4.1 vs 2.1 N, P < .001). The mean peak SSP gliding resistance during 0° to 60° glenohumeral abduction in IR in the intact condition was significantly higher compared with the subacromial decompression condition (4.1 vs 2.8 N, P = .021) and with the acromionectomy condition (4.1 vs 0.9 N, P < .001). During 0° to 60° glenohumeral abduction in ER, mean peak SSP gliding resistance in the intact condition was not significantly different compared with the subacromial decompression condition (2.1 vs 2.0 N, P = .999). The 2 specimens with a hooked (i.e. type III) acromion showed significantly higher mean peak SSP gliding resistance during glenohumeral abduction in IR and ER when compared with the 2 specimens with a flat (i.e. type I) acromion (IR: 5.8 vs 3.0 N, P = .006; ER: 2.8 vs 1.4 N, P = .001). Conclusions: In this cadaveric study, peak gliding resistance between the SSP tendon and the coracoacromial arch during combined abduction and IR was significantly reduced after anterolateral acromioplasty and was significantly higher in specimens with a hooked acromion. Clinical Relevance: The clinical benefit of subacromial decompression remains unclear. This study suggests that anterolateral acromioplasty might reduce supraspinatus gliding resistance in those with a hooked acromion and in the typical "impingement" position.

Prognostic value of clinical and MRI features in the screening of lipomatous lesions.

BACKGROUND AND OBJECTIVES: Differentiation of lipomatous tumors mostly requires diagnostic biopsy but is essential to decide for the most adequate therapy. This study aims to investigate the prognostic value of available clinical and radiological features with regard to malignancy of the lesion, recurrence and survival. METHODS: In this retrospective cohort study, 104 patients with a biopsy-proven lipomatous tumor between 2010 and 2015 and a minimum clinical follow-up of two years were enrolled. Next to clinical features (age, gender, location of the lesion, histopathologic diagnosis, stage of disease, time to recurrence and death), MRI parameters were recorded retrospectively and blinded to the histological diagnosis. RESULTS: Malignant lipomatous tumors were associated with location in the lower extremities and MRI features like thick septation (>2 mm), presence of a non-adipose mass, foci of high T2/STIR signal and contrast agent enhancement. A non-adipose mass was a predictor for recurrence and inferior overall survival, while lesions with high T2/STIR signal showed higher risk of recurrence only. In combination, clinical and radiological features (lower extremities, septation > 2 mm, existence of non-adipose mass, contrast enhancement, and foci of high T2/STIR signal) predicted a malignant lipomatous tumor with an accuracy of 0.941 (95% CI of 0.899-0.983; 87% sensitivity, 86% specificity). CONCLUSION: Localization and characteristic MR features predict malignancy in most lipomatous lesions. Non-adipose masses are a poor prognostic factor, being associated with tumor recurrence and disease-related death.

Osteoconductive Scaffold Placed at the Femoral Tunnel Aperture in Hamstring Tendon ACL Reconstruction: A Randomized Controlled Trial.

Background: Bone tunnel enlargement after single-bundle anterior cruciate ligament reconstruction remains an unsolved problem that complicates revision surgery. Hypothesis: Positioning of an osteoconductive scaffold at the femoral tunnel aperture improves graft-to-bone incorporation and thereby decreases bone tunnel widening. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: In a 1:1 ratio, 56 patients undergoing primary anterior cruciate ligament reconstruction were randomized to receive femoral fixation with cortical suspension fixation and secondary press-fit fixation at the tunnel aperture of the tendon graft only (control) or with augmentation by an osteoconductive scaffold (intervention). Adverse events, patient-reported outcomes, and passive knee stability were recorded over 2 years after the index surgery. Three-dimensional bone tunnel widening was assessed using computed tomography at the time of surgery and 4.5 months and 1 year postoperatively. Results: The intervention group exhibited a similar number of adverse events as the control group (8 vs 10; P = .775) including 2 partial reruptures in both groups. The approach was feasible, although 1 case was encountered where the osteoconductive scaffold was malpositioned without adversely affecting the patient's recovery. There was no difference between the intervention and control groups in femoral bone tunnel enlargement, as expressed by the relative change in tunnel volume from surgery to 4.5 months (mean ± SD, 36% ± 25% vs 40% ± 25%; P = .644) and 1 year (19% ± 20% vs 17% ± 25%; P =.698). Conclusion: Press-fit graft fixation with an osteoconductive scaffold positioned at the femoral tunnel aperture is safe but does not decrease femoral bone tunnel enlargement at postoperative 1 year. Registration: NCT03462823 (ClinicalTrials.gov identifier).

Why is female gender associated with poorer clinical outcomes after reverse total shoulder arthroplasty?

INTRODUCTION: There is a lack of gender-specific research after reverse total shoulder arthroplasty (RTSA). Although previous studies have documented worse outcomes in women, a more thorough understanding of why outcomes may differ is needed. We therefore asked: (1) Are there gender-specific differences in preoperative and postoperative clinical scores, complications, surgery-related parameters, and demographics? (2) Is female gender an independent risk factor for poorer clinical outcomes after RTSA? (3) If so, why is female gender associated with poorer outcomes after RTSA? MATERIALS AND METHODS: Between 2005 and 2019, 987 primary RTSAs were performed in our institution. After exclusion criteria were applied, data of 422 female and 271 male patients were analyzed. Clinical outcomes (absolute/relative Constant Score [a/rCS] and Subjective Shoulder Value [SSV]), complications (intra- and/or postoperative fracture, loosening), surgery-related parameters (indication, implant-related characteristics), and demographics (age, gender, body mass index, and number of previous surgeries) were evaluated. Preoperative and postoperative radiographs were analyzed (critical shoulder angle, deltoid-tuberosity index, reverse shoulder angle, lateralization shoulder angle, and distalization shoulder angle). RESULTS: Preoperative clinical scores (aCS, rCS, SSV, and pain level) and postoperative clinical outcomes (aCS and rCS) were significantly worse in women. However, the improvement between preoperative and postoperative outcomes was significantly higher in female patients for rCS (P = .037), internal rotation (P < .001), and regarding pain (P < .001). Female patients had a significantly higher number of intraoperative and postoperative fractures (24.9% vs. 11.4%, P < .001). The proportion of female patients with a deltoid-tuberosity index <1.4 was significantly higher than males (P = .01). Female gender was an independent negative predictor for postoperative rCS (P = .047, coefficient -0.084) and pain (P = .017, coefficient -0.574). In addition to female sex per se being a predictive factor of worse outcomes, females were significantly more likely to meet 2 of the 3 most significant predictive factors: (1) significantly worse preoperative clinical scores and (2) higher rate of intra- and/or postoperative fractures. CONCLUSIONS: Female sex is a very weak, but isolated, negative predictive factor that negatively affects the objective clinical outcome (rCS) after RTSA. However, differences did not reach the minimal clinically important difference, and it is not a predictor for the subjective outcome (SSV). The main reason for the worse outcome in female patients seems to be a combination of higher preoperative disability and higher incidence of fractures. To improve the outcome of women, all measures that contribute to the reduction of perioperative fracture risk should be used.

PIEZO1 gain-of-function gene variant is associated with elevated tendon stiffness in humans.

Prolonged periods of increased physical demands can elicit anabolic tendon adaptations that increase stiffness and mechanical resilience or conversely can lead to pathological processes that deteriorate tendon structural quality with ensuing pain and potential rupture. Although the mechanisms by which tendon mechanical loads regulate tissue adaptation are largely unknown, the ion channel PIEZO1 has been implicated in tendon mechanotransduction, with human carriers of the PIEZO1 gain-of-function variant E756del displaying improved dynamic vertical jump performance compared with noncarriers. Here, we sought to examine whether increased tendon stiffness in humans could explain this increased performance. We assessed tendon morphological and mechanical properties with ultrasound-based techniques in 77 participants of Middle- and West-African descent, and we measured their vertical jumping performance to assess potential functional consequences in the context of high tendon strain-rate loading. Carrying the E756del gene variant (n = 30) was associated with 46.3 ± 68.3% (P = 0.002) and 45.6 ± 69.2% (P < 0.001) higher patellar tendon stiffness and Young's modulus compared with noncarrying controls, respectively. Although these tissue level measures strongly corroborate the initial postulate that PIEZO1 plays an integral part in regulating tendon material properties and stiffness in humans, we found no detectable correlation between tendon stiffness and jumping performance in the tested population that comprised individuals of highly diverse physical fitness level, dexterity, and jumping ability.NEW & NOTEWORTHY The E756del gene variant causes overactivity of the mechanosensitive membrane channel PIEZO1 and is suspected to upregulate tendon collagen cross linking. In human carriers of E756del, we found increased patellar tendon stiffness but similar tendon lengths and cross-sectional areas, directly supporting the premise that PIEZO1 regulates human tendon stiffness at the level of tissue material properties.

Muscle atrophy in diabetic patients with Charcot foot: a case-control study.

PURPOSE: To evaluate the distribution and severity of muscle atrophy in diabetic patients with active Charcot foot (CF) compared to diabetic patients without CF. Furthermore, to correlate the muscle atrophy with severity of CF disease. MATERIAL/METHODS: In this retrospective study, MR images of 35 diabetic patients (21 male, median:62.1 years ± 9.9SD) with active CF were compared with an age- and gender-matched control group of diabetic patients without CF. Two readers evaluated fatty muscle infiltration (Goutallier-classification) in the mid- and hindfoot. Furthermore, muscle trophic (cross-sectional muscle area (CSA)), intramuscular edema (none/mild versus moderate/severe), and the severity of CF disease (Balgrist Score) were assessed. RESULTS: Interreader correlation for fatty infiltration was substantial to almost perfect (kappa-values:0.73-1.0). Frequency of fatty muscle infiltration was high in both groups (CF:97.1-100%; control:77.1-91.4%), but severe infiltration was significantly more frequent in CF patients (p-values: < 0.001-0.043). Muscle edema was also frequently seen in both groups, but significantly more often in the CF group (p-values: < 0.001-0.003). CSAs of hindfoot muscles were significantly smaller in the CF group. For the flexor digitorum brevis muscle, a cutoff value of 139 mm2 (sensitivity:62.9%; specificity:82.9%) in the hindfoot was found to differentiate between CF disease and the control group. No correlation was seen between fatty muscle infiltration and the Balgrist Score. CONCLUSION: Muscle atrophy and muscle edema are significantly more severe in diabetic patients with CF disease. Muscle atrophy does not correlate with the severity of active CF disease. A CSA < 139 mm2 of the flexor digitorum brevis muscle in the hindfoot may indicate CF disease.

A Randomized Trial of Intra-articular Injection Therapy for Knee Osteoarthritis.

BACKGROUND: Intra-articular injections are widely used for conservative treatment of knee osteoarthritis (OA). However, rigorous data are lacking regarding the comparative therapeutic effectiveness of these injections. PURPOSE: The aim of this study was to compare clinical outcomes after intra-articular injections of glucocorticoid, hyaluronic acid, platelet-rich plasma (PRP), or placebo in patients with mild or moderate OA of the knee. MATERIALS AND METHODS: In a double-blinded, placebo-controlled, single-center trial, we randomly assigned knees with early- to middle-stage knee OA (Kellgren-Lawrence grade 1-3) to an intra-articular injection with one of these substances: glucocorticoid, hyaluronic acid, PRP, or placebo. Primary outcome was pain reduction within 6 months after the injection, assessed with the numeric rating scale (NRS; range, 0-100). Secondary outcome parameters included WOMAC scores, Tegner Activity Scale, knee mobility, and adverse events. Finally, a linear mixed-effects model was calculated and corrected for possible patient and covariate effects. RESULTS: One hundred twenty knees (30 knees per treatment group) in 95 patients (41 female) were included in the final analysis. The median age of patients was 60 years (interquartile range, 54.0-68.0). There was no evidence that the drug effects of primary and secondary outcome parameters differed over time. The median pain at baseline was 32.5 (interquartile range, 15.00-50.00) on NRS. The changes in pain level during the first 6 months compared with baseline were small (within ±5 points on NRS), whereas the intrapatient variability was large between -20 and +20 points. Secondary outcome parameters did not differ significantly among the groups. Kellgren-Lawrence grade did not have a statistically significant effect on pain reduction ( P = 0.61). CONCLUSIONS: There is no evidence that knee injections with glucocorticoid, PRP, or hyaluronic acid have superior short- or long-term effects in patients with low pain level at baseline and early- to middle-stage knee OA when compared with placebo.

Improved suture pullout through genipin-coated sutures in human biceps tendons with spatially confined changes in cell viability.

BACKGROUND: The suture-tendon interface often constitutes the point of failure in tendon suture repair. In the present study, we investigated the mechanical benefit of coating the suture with a cross-linking agent to strengthen the nearby tissue after suture placement in human tendons and we assessed the biological implications regarding tendon cell survival in-vitro. METHODS: Freshly harvested human biceps long head tendons were randomly allocated to control (n = 17) or intervention (n = 19) group. According to the assigned group, either an untreated or a genipin-coated suture was inserted into the tendon. 24 h after suturing, mechanical testing composed of cyclic and ramp-to-failure loading was performed. Additionally, 11 freshly harvested tendons were used for short-term in vitro cell viability assessment in response to genipin-loaded suture placement. These specimens were analyzed in a paired-sample setting as stained histological sections using combined fluorescent/light microscopy. FINDINGS: Tendons stitched with a genipin-coated suture sustained higher forces to failure. Cyclic and ultimate displacement of the tendon-suture construct remained unaltered by the local tissue crosslinking. Tissue crosslinking resulted in significant cytotoxicity in the direct vicinity of the suture (<3 mm). At larger distances from the suture, however, no difference in cell viability between the test and the control group was discernable. INTERPRETATION: The repair strength of a tendon-suture construct can be augmented by loading the suture with genipin. At this mechanically relevant dosage, crosslinking-induced cell death is confined to a radius of <3 mm from the suture in the short-term in-vitro setting. These promising results warrant further examination in-vivo.

No Difference in Risk of Amputation or Frequency of Surgical Interventions Between Patients With Diabetic and Nondiabetic Charcot Arthropathy.

BACKGROUND: The cause of Charcot neuro-osteoarthropathy (CN) is diabetes in approximately 75% of patients. Most reports on the clinical course and complications of CN focus on diabetic CN, and reports on nondiabetic CN are scarce. No study, to our knowledge, has compared the clinical course of patients initially treated nonoperatively for diabetic and nondiabetic CN. QUESTIONS/PURPOSES: Among patients with CN, are there differences between patients with diabetes and those without in terms of (1) the frequency of major amputation as ascertained by a competing risks survivorship estimator; (2) the frequency of surgery as ascertained by a competing risks survivorship estimator; (3) frequency of reactivation, as above; or (4) other complications (contralateral CN development or ulcers)? METHODS: Between January 1, 2006, and December 31, 2018, we treated 199 patients for diabetic CN. Eleven percent (22 of 199) were lost before the minimum study follow-up of 2 years or had incomplete datasets and could not be analyzed, and another 9% (18 of 199) were excluded for other prespecified reasons, leaving 80% (159 of 199) for analysis in this retrospective study at a mean follow-up duration since diagnosis of 6 ± 4 years. During that period, we also treated 78 patients for nondiabetic Charcot arthropathy. Eighteen percent (14 of 78) were lost before the minimum study follow-up and another 5% (four of 78 patients) were excluded for other prespecified reasons, leaving 77% (60 of 78) of patients for analysis here at a mean of 5 ± 3 years. Patients with diabetic CN were younger (59 ± 11 years versus 68 ± 11 years; p < 0.01), more likely to smoke cigarettes (37% [59 of 159] versus 20% [12 of 60]; p = 0.02), and had longer follow-up (6 ± 4 years versus 5 ± 3 years; p = 0.02) than those with nondiabetic CN. Gender, BMI, overall renal failure, dialysis, and presence of peripheral arterial disease did not differ between the groups. Age difference and length of follow-up were not considered disqualifying problems because of the later onset of idiopathic neuropathy and longer available patient follow-up in patients with diabetes, because our program adheres to the follow-up recommendations suggested by the International Working Group on the Diabetic Foot. Treatment was the same in both groups and included serial total-contact casting and restricted weightbearing until CN had resolved. Then, patients subsequently transitioned to orthopaedic footwear. CN reactivation was defined as clinical signs of the recurrence of CN activity and confirmation on MRI. Group-specific risks of the frequencies of major amputation, surgery, and CN reactivation were calculated, accounting for competing events. Group comparisons and confounder analyses were conducted on these data with a Cox regression analysis. Other complications (contralateral CN development and ulcers) are described descriptively to avoid pooling of complications with varying severity, which could be misleading. RESULTS: The risk of major amputation (defined as an above-ankle amputation), estimated using a competing risks survivorship estimator, was not different between the diabetic CN group and nondiabetic CN group at 10 years (8.8% [95% confidence interval 4.2% to 15%] versus 6.9% [95% CI 0.9% to 22%]; p = 0.4) after controlling for potentially confounding variables such as smoking and peripheral artery disease. The risk of any surgery was no different between the groups as estimated by the survivorship function at 10 years (53% [95% CI 42% to 63%] versus 58% [95% CI 23% to 82%]; p = 0.3), with smoking (hazard ratio 2.4 [95% CI 1.6 to 3.6]) and peripheral artery disease (HR 2.2 [95% CI 1.4 to 3.4]) being associated with diabetic CN. Likewise, there was no between-group difference in CN reactivation at 10 years (16% [95% CI 9% to 23%] versus 11% [95% CI 4.5% to 22%]; p = 0.7) after controlling for potentially confounding variables such as smoking and peripheral artery disease. Contralateral CN occurred in 17% (27 of 159) of patients in the diabetic group and in 10% (six of 60) of those in the nondiabetic group. Ulcers occurred in 74% (117 of 159) of patients in the diabetic group and in 65% (39 of 60) of those in the nondiabetic group. CONCLUSION: Irrespective of whether the etiology of CN is diabetic or nondiabetic, our results suggest that orthopaedic surgeons should use similar nonsurgical treatments, with total-contact casting until CN activity has resolved, and then proceed with orthopaedic footwear. A high frequency of foot ulcers must be anticipated and addressed as part of the treatment approach. LEVEL OF EVIDENCE: Level III, prognostic study.

Altered regional 3D shear wave velocity patterns in youth competitive alpine skiers suffering from patellar tendon complaints - a prospective case-control study.

Patellar tendon (PT) complaints are frequent throughout the population, with increased occurrence in athletes and, particularly, in youth competitive alpine skiers. Timely detection and treatment might improve prospects of recovery. Diagnostic modalities in clinical use to date rely on pain symptoms, manual palpation, and potentially, magnetic resonance imaging (MRI); however, MRI-based imaging yields limited sensitivity. Quantitatively measuring the morphological and mechanical properties of PTs by means of B-mode ultrasound and shear wave elastography (SWE), instead, may allow improved diagnosis or even early detection. We performed B-mode scans and three-dimensional ultrasound shear wave velocity (SWV) mapping and MRI of the PT in 106 youth skiers. A prospective one-year survey on health problems combined with clinical assessments served to categorize symptomatic and asymptomatic youth skiers. Skiers suffering from distal or proximal tendon complaints showed lower SWV in the respective tendon region than asymptomatic skiers (p = 0.035 and p = 0.019, respectively). Youth skiers with distal tendon complaints additionally exhibited decreased SWV in the proximal region compared to asymptomatic counterparts (p = 0.020). Cross-validated analysis of retrospective prediction indicated sensitivity and specificity in detecting tendon complaints in the range of 0.606-0.621 and 0.536-0.650, respectively. MRI detected distal tendon complaints with a sensitivity of 0.410 (12/29) but failed to detect any proximal cases. This study agrees with the most recent literature in that SWE holds promise as a valuable adjunct modality for the diagnosis of PT complaints or even the detection of subclinical prestages. However, to evaluate its prospective predictive value, long-term studies are warranted.Highlights Patellar tendon complaints are a frequent complaint in athletes, particularly in youth competitive alpine skiers, but timely quantitative detection of related tendon properties remains challenging.Quantitative B-mode US and three-dimensional ultrasound shear wave elastography assessments and magnetic resonance imaging were performed in youth competitive alpine skiers.Three-dimensional shear wave elastography was able to discern symptomatic from asymptomatic patellar tendons both in the distal and proximal tendon regions, whereas magnetic resonance imaging failed to detect any proximal cases.

Atypical patterns of spinal segment degeneration in patients with abdominal aortic aneurysms.

PURPOSE: Abdominal aortic aneurysms (AAAs) affect the vascular perfusion of the lumbar spine. The treatment of AAAs with endovascular aortic aneurysm repair (EVAR) completely occludes the direct vascular supply to the lumbar spine. We hypothesized that patients with AAA who undergo EVAR show a different pattern of spinal degeneration than individuals without AAA. METHODS: In this retrospective institutional review board-approved study, 100 randomly selected patients with AAA who underwent EVAR with computed tomography (CT) scans between 2005 and 2017 were compared with age- and gender-matched controls without AAA. In addition, long-term follow-up CT images (> 6 months before EVAR, at the time of EVAR, and > 12 months after EVAR) of the patients were analysed to compare the progression of degeneration from before to after EVAR. Degeneration scores, lumbar levels with the most severe degeneration, and lumbar levels with progressive degeneration were analysed in all CT images. Fisher's exact test, Wilcoxon signed-rank test, and Mann-Whitney U test were performed for statistical analyses. RESULTS: Compared with the control group (n = 94), the most severe degeneration was more commonly detected in the mid-lumbar area in the patient group (n = 100, p = 0.016), with significantly more endplate erosions being detected in the lumbar spine (p = 0.015). However, EVAR did not result in significant additional acceleration of the degenerative process in the long-term follow-up analysis (n = 51). CONCLUSION: AAA is associated with atypical, more cranially located spinal degradation, particularly in the mid-lumbar segments; however, EVAR does not seem to additionally accelerate the degenerative process. This observation underlines the importance of disc and endplate vascularization in the pathomechanism of spinal degeneration. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

The periacetabular osteotomy: angulation of the supraacetabular osteotomy for quantification of correction.

BACKGROUND: Malcorrection of the acetabular fragment in periacetabular osteotomy (PAO) is associated with inferior outcomes. 2-dimensional radiographic parameters are being used for intraoperative verification of a satisfactory result. After reorientation of the fragment, the acetabular version must be verified with an intraoperative radiograph. In the case of an unsatisfactory correction, a reorientation would be required. A slim and radiation-free intraoperative navigation method to directly quantify the correction is highly desirable. AIM: To find out whether the measurable angulation of the supraacetabular osteotomy can be used for this purpose. METHODS: To determine the angulation, 13 consecutive patients who underwent a PAO were investigated. The preoperative and postoperative standard radiographs as well as CT scans were available. The surgically produced alteration of radiographic parameters was correlated to tilting and spreading of the supraacetabular osteotomy planes. RESULTS: Tilting of the supraacetabular osteotomy planes correlates strongly to alteration of the lateral centre-edge angle (LCEA) and the acetabular index (ACI), whereas spreading of the same planes showed also a strong correlation, but to the LCEA only. 1° of tilting resulted in a 0.2° alteration of the LCEA and a 0.5° alteration of the ACI, whereas 1° of spreading resulted in a 0.5° alteration of the LCEA. CONCLUSIONS: This study shows that the measurable angulation of the supraacetabular osteotomy planes can be used to monitor the three-dimensional reorientation of the acetabular fragment in PAO. As long as sophisticated modalities are lacking, this technique offers an easy way to intraoperatively navigate the correction in PAO.

Salami-Tactics: when is it time for a major cut after multiple minor amputations?

INTRODUCTION: Repetitive minor amputations carry the concomitant risks of multiple surgical procedures, major amputations have physical and economical major drawbacks. The aim of this study was to evaluate whether there is a distinct number of minor amputations predicting a major amputation in the same leg and to determine risk factors for major amputation in multiple minor amputations. MATERIALS AND METHODS: A retrospective chart review including 429 patients with 534 index minor amputations between 07/1984 and 06/2019 was conducted. Patient demographics and clinical data including number and level of re-amputations were extracted from medical records and statistically analyzed. RESULTS: 290 legs (54.3%) had one or multiple re-amputations after index minor amputation. 89 (16.7%) legs needed major amputation during follow up. Major amputation was performed at a mean of 32.5 (range 0 - 275.2) months after index minor amputation. No particular re-amputation demonstrated statistically significant elevated odds ratio (a.) to be a major amputation compared to the preceding amputation and (b.) to lead to a major amputation at any point during follow up. Stepwise multivariate Cox regression analysis revealed minor re-amputation within 90 days (HR 3.8, 95% CI 2.0-7.3, p <0.001) as the only risk factor for major amputation if at least one re-amputation had to be performed. CONCLUSIONS: There is no distinct number of prior minor amputations in one leg that would justify a major amputation on its own. If a re-amputation has to be done, the timepoint needs to be considered as re-amputations within 90 days carry a fourfold risk for major amputation. LEVEL OF EVIDENCE: Retrospective comparative study (Level III).

Investigation of the relationship between tensile viscoelasticity and unloaded ultrasound shear wave measurements in ex vivo tendon.

Mechanical properties of biological tissues are of key importance for proper function and in situ methods for mechanical characterization are sought after in the context of both medical diagnosis as well as understanding of pathophysiological processes. Shear wave elastography (SWE) and accompanying physical modelling methods provide valid estimates of stiffness in quasi-linear viscoelastic, isotropic tissue but suffer from limitations in assessing non-linear viscoelastic or anisotropic material, such as tendon. Indeed, mathematical modelling predicts the longitudinal shear wave velocity to be unaffected by the tensile but rather the shear viscoelasticity. Here, we employ a heuristic experimental testing approach to the problem to assess the most important potential confounders, namely tendon mass density and diameter, and to investigate associations between tendon tensile viscoelasticity with shear wave descriptors. Small oscillatory testing of animal flexor tendons at two baseline stress levels over a large frequency range comprehensively characterized tensile viscoelastic behavior. A broad set of shear wave descriptors was retrieved on the unloaded tendon based on high frame-rate plane wave ultrasound after applying an acoustic deformation impulse. Tensile modulus and strain energy dissipation increased logarithmically and linearly, respectively, with the frequency of the applied strain. Shear wave descriptors were mostly unaffected by tendon diameter but were highly sensitive to tendon mass density. Shear wave group and phase velocity showed no association with tensile elasticity or strain rate-stiffening but did show an association with tensile strain energy dissipation. The longitudinal shear wave velocity may not characterize tensile elasticity but rather tensile viscous properties of transversely isotropic collagenous tissues.

Malunion deformity of the forearm: Three-dimensional length variation of interosseous membrane and bone collision.

It remains unclear to what extent the interosseous membrane (IOM) is affected through the whole range of motion (ROM) in posttraumatic deformities of the forearm. The purpose of this study is to describe the ligament- and bone-related factors involved in rotational deficit of the forearm. Through three-dimensional (3D) kinematic simulations on one cadaveric forearm, angular deformities of 5° in four directions (flexion, extension, valgus, varus) were produced at two locations of the radius and the ulna (proximal and distal third). The occurrence of bone collision in pronation and the linear length variation of six parts of the IOM through the whole ROM were compared between the 32 types of forearm deformities. Similar patterns could be observed among four groups: 12 types of deformity presented increased bone collision in pronation, 8 presented an improvement of bone collision with an increase of the mean linear lengthening of the IOM in neutral rotation, 6 had an increased linear lengthening of the IOM in supination with nearly unchanged bone collision in pronation and 6 types presented nearly unchanged bone collision in pronation with a shortening of the mean linear length of IOM in supination or neutral rotation. This kinematic analysis provides a better understanding of the ligament- and bone-related factors expected to cause rotational deficit in forearm deformity and may help to refine the surgical indications of patient-specific corrective osteotomy.

Three-dimensional mapping of ultrasound-derived skeletal muscle shear wave velocity.

Introduction: The mechanical properties of skeletal muscle are indicative of its capacity to perform physical work, state of disease, or risk of injury. Ultrasound shear wave elastography conducts a quantitative analysis of a tissue's shear stiffness, but current implementations only provide two-dimensional measurements with limited spatial extent. We propose and assess a framework to overcome this inherent limitation by acquiring numerous and contiguous measurements while tracking the probe position to create a volumetric scan of the muscle. This volume reconstruction is then mapped into a parameterized representation in reference to geometric and anatomical properties of the muscle. Such an approach allows to quantify regional differences in muscle stiffness to be identified across the entire muscle volume assessed, which could be linked to functional implications. Methods: We performed shear wave elastography measurements on the vastus lateralis (VL) and the biceps femoris long head (BFlh) muscle of 16 healthy volunteers. We assessed test-retest reliability, explored the potential of the proposed framework in aggregating measurements of multiple subjects, and studied the acute effects of muscular contraction on the regional shear wave velocity post-measured at rest. Results: The proposed approach yielded moderate to good reliability (ICC between 0.578 and 0.801). Aggregation of multiple subject measurements revealed considerable but consistent regional variations in shear wave velocity. As a result of muscle contraction, the shear wave velocity was elevated in various regions of the muscle; showing pre-to-post regional differences for the radial assessement of VL and longitudinally for BFlh. Post-contraction shear wave velocity was associated with maximum eccentric hamstring strength produced during six Nordic hamstring exercise repetitions. Discussion and Conclusion: The presented approach provides reliable, spatially resolved representations of skeletal muscle shear wave velocity and is capable of detecting changes in three-dimensional shear wave velocity patterns, such as those induced by muscle contraction. The observed systematic inter-subject variations in shear wave velocity throughout skeletal muscle additionally underline the necessity of accurate spatial referencing of measurements. Short high-effort exercise bouts increase muscle shear wave velocity. Further studies should investigate the potential of shear wave elastography in predicting the muscle's capacity to perform work.

Clinical relevance of occult infections in spinal pseudarthrosis revision.

Background: Occult infections in spinal pseudarthrosis revisions have been reported in the literature, but the relevance of such an infection on patient outcomes is unknown. We aimed to elucidate clinical outcomes and re-revision risks between patients with and without occult infections in spinal revision surgery for pseudarthrosis. Methods: In this matched case-control study, we identified 128 patients who underwent thoracolumbar revision surgery from 2014-2019 for pseudarthrosis of the spine. Among them, 13 (10.2%) revealed an occult infection (defined by at least two positive intraoperative tissue samples with the same pathogen), and nine of these 13 were available for follow-up. We selected 18 of the 115 controls using a 2:1 fuzzy matching based on fusion length and length of follow-up. The patients were followed up to assess subsequent re-revision surgeries and the following postoperative patient-reported outcome measures (PROMs): overall satisfaction, Oswestry Disability Index, 5-level EQ-5D, and Short Form 36. Results: Patient characteristics, surgical data, and length of follow-up were equal between both study groups. The rate of re-revision free survival after the initial pseudarthrosis revision surgery was higher in the occult infection group (77.8%) than the non-infectious controls (44.4%), although not significantly (0.22). The total number of re-revision surgeries, including re-re-revisions, was thirteen (in ten patients) in the control and two (in two patients) in the occult infection group (p = 0.08) after a median follow-up of 24 months (range 13-75). Four cases in the control group underwent re-revision for pseudarthrosis compared to none in the infected group. Satisfactory scores were recorded in all PROMs, with similar scores between the two groups. Conclusions: The presence of an occult infection accompanying spinal pseudarthrosis revision was not inferior to non-infected pseudarthrosis revisions in a matched, small sample size cohort study. This may be explained due to the possibility of targeted treatment of the identified cause of pseudarthrosis.