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.

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.

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).

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.

Muscle Degeneration Induced by Sequential Release and Denervation of the Rotator Cuff Tendon in Sheep.

BACKGROUND: In a sheep rotator cuff model, tenotomy predominantly induces fatty infiltration, and denervation induces mostly muscle atrophy. In clinical practice, myotendinous retraction after tendon tear or lateralization after tendon repair tear may lead to traction injury of the nerve. PURPOSE/HYPOTHESIS: To analyze whether an additional nerve lesion during rotator cuff repair leads to further degeneration of the rotator cuff muscle in the clinical setting. We hypothesized that neurectomy after tendon tear would increase atrophy as well as fatty infiltration and that muscle paralysis after neurectomy would prevent myotendinous retraction after secondary tendon release. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve Swiss alpine sheep were used for this study. For the 6 sheep in the tenotomy/neurectomy (T/N) group, the infraspinatus tendon was released; 8 weeks later, the suprascapular nerve was transected. For the 6 sheep in the neurectomy/tenotomy (N/T) group, neurectomy was performed, and the infraspinatus was tenotomized 8 weeks later. All sheep were sacrificed after 16 weeks. Magnetic resonance imaging (MRI) was performed before the first surgery (baseline) and then after 8 and 16 weeks. The MRI data were used to assess muscle volume, fat fraction, musculotendinous retraction, pennation angle, and muscle fiber length of the infraspinatus muscle. RESULTS: Three sheep (2 in the T/N and 1 in the N/T group) had to be excluded because the neurectomy was incomplete. After 8 weeks, muscle volume decreased significantly less in the T/N group (73% ± 2% of initial volume vs 52% ± 7% in the N/T group; P < .001). After 16 weeks, the mean intramuscular fat increase was higher in the T/N group (36% ± 9%) than in the N/T group (23% ± 6%), without reaching significance (P = .060). After 16 weeks, the muscle volumes of the N/T (52% ± 8%) and T/N (49% ± 3%) groups were the same (P = .732). CONCLUSION: Secondary neurectomy after tenotomy of a musculotendinous unit increases muscle atrophy. Tenotomy of a denervated muscle is associated with substantial myotendinous retraction but not with an increase of fatty infiltration to the level of the tenotomy first group. CLINICAL RELEVANCE: Substantial retraction, which is associated with hitherto irrecoverable fatty infiltration, should be prevented, and additional neurogenic injury during repair should be avoided to limit the development of further atrophy.

Augmented reality in the operating room: a clinical feasibility study.

BACKGROUND: Augmented Reality (AR) is a rapidly emerging technology finding growing acceptance and application in different fields of surgery. Various studies have been performed evaluating the precision and accuracy of AR guided navigation. This study investigates the feasibility of a commercially available AR head mounted device during orthopedic surgery. METHODS: Thirteen orthopedic surgeons from a Swiss university clinic performed 25 orthopedic surgical procedures wearing a holographic AR headset (HoloLens, Microsoft, Redmond, WA, USA) providing complementary three-dimensional, patient specific anatomic information. The surgeon's experience of using the device during surgery was recorded using a standardized 58-item questionnaire grading different aspects on a 100-point scale with anchor statements. RESULTS: Surgeons were generally satisfied with image quality (85 ± 17 points) and accuracy of the virtual objects (84 ± 19 point). Wearing the AR device was rated as fairly comfortable (79 ± 13 points). Functionality of voice commands (68 ± 20 points) and gestures (66 ± 20 points) provided less favorable results. The greatest potential in the use of the AR device was found for surgical correction of deformities (87 ± 15 points). Overall, surgeons were satisfied with the application of this novel technology (78 ± 20 points) and future access to it was demanded (75 ± 22 points). CONCLUSION: AR is a rapidly evolving technology with large potential in different surgical settings, offering the opportunity to provide a compact, low cost alternative requiring a minimum of infrastructure compared to conventional navigation systems. While surgeons where generally satisfied with image quality of the here tested head mounted AR device, some technical and ergonomic shortcomings were pointed out. This study serves as a proof of concept for the use of an AR head mounted device in a real-world sterile setting in orthopedic surgery.

The quantitative influence of current treatment options on patellofemoral stability in patients with trochlear dysplasia and symptomatic patellofemoral instability - a finite element simulation.

BACKGROUND: Trochlear dysplasia is highly associated with patellofemoral instability. The goal of conservative and surgical treatment is to stabilize the patella while minimizing adverse effects. However, there is no literature investigating the quantitative influence of different treatment options on patellofemoral stability in knees with trochlear dysplasia. We created and exploited a range of finite element models to address this gap in knowledge. METHODS: MRI data of 5 knees with trochlear dysplasia and symptomatic patellofemoral instability were adapted into this previously established model. Vastus medialis obliquus strengthening as well as double-bundle medial patellofemoral ligament reconstruction and the combination of medial patellofemoral ligament reconstruction and trochleoplasty were simulated. The force necessary to dislocate the patella by 10 mm and fully dislocate the patella was calculated in different flexion angles. FINDINGS: Our model predicts a significant increase of patellofemoral stability at the investigated flexion angles (0°-45°) for a dislocation of 10 mm and a full dislocation after medial patellofemoral ligament reconstruction and the combination of medial patellofemoral ligament reconstruction and trochleoplasty compared to trochleodysplastic (P = 0.01) and healthy knees (P = 0.01-0.02). Vastus medialis obliquus strengthening has a negligible effect on patellofemoral stability. INTERPRETATIONS: This is the first objective quantitative biomechanical evidence supporting the place of medial patellofemoral ligament reconstruction and medial patellofemoral ligament reconstruction combined with trochleoplasty in patients with symptomatic patellofemoral instability and trochlear dysplasia type B. Vastus medialis obliquus strengthening has a negligible effect on patellar stability at a low total quadriceps load of 175 N.

Augmented Reality Navigated Sacral-Alar-Iliac Screw Insertion.

BACKGROUND: Sacral-alar-iliac (SAI) screws are increasingly used for lumbo-pelvic fixation procedures. Insertion of SAI screws is technically challenging, and surgeons often rely on costly and time-consuming navigation systems. We investigated the accuracy and precision of an augmented reality (AR)-based and commercially available head-mounted device requiring minimal infrastructure. METHODS: A pelvic sawbone model served to drill pilot holes of 80 SAI screw trajectories by 2 surgeons, randomly either freehand (FH) without any kind of navigation or with AR navigation. The number of primary pilot hole perforations, simulated screw perforation, minimal axis/outer cortical wall distance, true sagittal cranio-caudal inclination angle (tSCCIA), true axial medio-lateral angle, and maximal screw length (MSL) were measured and compared to predefined optimal values. RESULTS: In total, 1/40 (2.5%) of AR-navigated screw hole trajectories showed a perforation before passing the inferior gluteal line compared to 24/40 (60%) of FH screw hole trajectories (P < .05). The differences between FH- and AR-guided holes compared to optimal values were significant for tSCCIA with -10.8° ± 11.77° and MSL -65.29 ± 15 mm vs 55.04 ± 6.76 mm (P = .001). CONCLUSIONS: In this study, the additional anatomical information provided by the AR headset and the superimposed operative plan improved the precision of drilling pilot holes for SAI screws in a laboratory setting compared to the conventional FH technique. Further technical development and validation studies are currently being performed to investigate potential clinical benefits of the AR-based navigation approach described here. LEVEL OF EVIDENCE: 4.

Inter-rater variability of three-dimensional fracture reduction planning according to the educational background.

BACKGROUND: Computer-assisted three-dimensional (3D) planning is increasingly delegated to biomedical engineers. So far, the described fracture reduction approaches rely strongly on the performance of the users. The goal of our study was to analyze the influence of the two different professional backgrounds (technical and medical) and skill levels regarding the reliability of the proposed planning method. Finally, a new fragment displacement measurement method was introduced due to the lack of consistent methods in the literature. METHODS: 3D bone models of 20 distal radius fractures were presented to nine raters with different educational backgrounds (medical and technical) and various levels of experience in 3D operation planning (0 to 10 years) and clinical experience (1.5 to 24 years). Each rater was asked to perform the fracture reduction on 3D planning software. RESULTS: No difference was demonstrated in reduction accuracy regarding rotational (p = 1.000) and translational (p = 0.263) misalignment of the fragments between biomedical engineers and senior orthopedic residents. However, a significantly more accurate planning was performed in these two groups compared with junior orthopedic residents with less clinical experience and no 3D planning experience (p < 0.05). CONCLUSION: Experience in 3D operation planning and clinical experience are relevant factors to plan an intra-articular fragment reduction of the distal radius. However, no difference was observed regarding the educational background (medical vs. technical) between biomedical engineers and senior orthopedic residents. Therefore, our results support the further development of computer-assisted surgery planning by biomedical engineers. Additionally, the introduced fragment displacement measure proves to be a feasible and reliable method. LEVEL OF EVIDENCE: Diagnostic Level II.

Biomechanical and Clinical Evaluation of the Optimal Arm Position After Rotator Cuff Surgery With an Adjustable Abduction Brace.

Abduction braces are used with the intention of relieving tension on the supraspinatus, thereby protecting an operative repair. It is not known, however, whether patients wearing a brace do deposit the weight of the arm on the brace effectively or actively stabilize the arm despite the brace. It is further unknown what position of the arm is most effective to relax the shoulder and is considered most comfortable. Twenty-two patients who had undergone an arthroscopic supraspinatus repair were postoperatively fitted with a standard abduction brace equipped with a torque sensor to measure the weight of the arm on the brace on the first and second postoperative days. The most comfortable arm position, tear size, and degenerative muscular changes on magnetic resonance imaging were assessed. Most patients (15 vs 5) preferred a low angle of abduction with the brace in the scapular rather than the true frontal plane irrespective of tear location or size. While loads applied to the brace were slightly higher at high abduction angles (70° and 90°) under regional anesthesia (day 1), they were significantly higher at low abduction angles (30° and 50°) with the arm fully awake (day 2). The most comfortable brace position-which is at low angles of abduction (30° to 50°) in the scapular plane-is associated with the highest load transfer to the brace in the unanesthetized arm. The authors therefore conclude that if an abduction brace is used, it should be fitted in the scapular plane with an abduction angle between 30° and 50°. [Orthopedics. 2021;44(1):e1-e6.].

Long-term results after internal partial forefoot amputation (resection): a retrospective analysis.

INTRODUCTION: Internal partial forefoot amputation (IPFA) is a treatment option for osteomyelitis and refractory and recurrent chronic ulcers of the forefoot. The aim of our study was to assess the healing rate of chronic ulcers, risk of ulcer recurrence at the same area or re-ulceration at a different area and revision rate in patients treated with IPFA. MATERIALS AND METHODS: All patients who underwent IPFA of a phalanx and/or metatarsal head and/or sesamoids at our institution because of chronic ulceration of the forefoot and/or osteomyelitis from 2004 to 2014 were included. Information about patient characteristics, ulcer healing, new ulcer occurrence, and revision surgery were collected. Kaplan-Meier survival curves were plotted for new ulcer occurrence and revision surgery. RESULTS: A total of 102 patients were included (108 operated feet). 55.6% of our patients had diabetes. In 44 cases, an IPFA of a phalanx was performed, in 60 cases a metatarsal head resection and in 4 cases an isolated resection of sesamoids. The mean follow-up was 40.9 months. 91.2% of ulcers healed after a mean period of 1.3 months. In 56 feet (51.9%), a new ulcer occurred: 11 feet (10.2%) had an ulcer in the same area as initially (= ulcer recurrence), in 45 feet (41.7%) the ulcer was localized elsewhere (= re-ulceration). Revision surgery was necessary in 39 feet (36.1%). Only one major amputation and five complete transmetatarsal forefoot amputations were necessary during the follow-up period. Thus, the major amputation rate was 0.9%, and the minor amputation rate on the same ray was 13.9%. CONCLUSIONS: IPFA is a valuable treatment of chronic ulcers of the forefoot. However, new ulceration is a frequent event following this type of surgery. Our results are consistent with the reported re-ulceration rate after conservative treatment of diabetic foot ulcers. The number of major amputations is low after IPFA. LEVEL OF EVIDENCE: Retrospective Case Series Study (Level IV).

Hand or foot train-of-four tests and surgical site muscle relaxation assessed with multiple motor evoked potentials: A prospective observational study.

BACKGROUND: Intra-operative muscle relaxation is often required in orthopaedic surgery and the hand train-of-four (TOF) test is usually used for its quantification. However, even though full muscle relaxation is claimed by anaesthesiologists based on a TOF count of zero, surgeons observe residual muscle activity. OBJECTIVE: The aim of the study was to assess if hand or foot TOF adequately represents intra-operative muscle relaxation compared with multiple motor evoked potentials. DESIGN: Prospective observational study. SETTING: A single-centre study performed between February 2016 and December 2018 at the Balgrist University Hospital, Zurich, Switzerland. PATIENTS: Twenty patients scheduled for elective lumbar spinal fusion were prospectively enrolled in this study after giving written informed consent. INTERVENTIONS: To assess neuromuscular blockade (NMB) with the intermediate duration nondepolarising neuromuscular blocking agent rocuronium, hand TOF (adductor pollicis) and foot TOF (flexor hallucis brevis) monitoring, and muscle motor evoked potentials (MMEPs) from the upper and lower extremities were assessed prior to surgery under general anaesthesia. Following baseline measurements, muscle relaxation was performed with rocuronium until the spinal surgeon observed sufficient relaxation for surgical intervention. At this timepoint, NMB was assessed by TOF and MMEP. MAIN OUTCOME MEASURES: The primary outcome was to determine the different effect of rocuronium on muscle relaxation comparing hand and foot TOF with the paraspinal musculature assessed by MMEP. RESULTS: Hand TOF was more resistant to NMB and had a shorter recovery time than foot TOF. When comparing MMEPs, muscle relaxation occurred first in the hip abductors, and the paraspinal and deltoid muscles. The most resistant muscle to NMB was the abductor digiti minimi. Direct comparison showed that repetitive MMEPs simultaneously recorded from various muscles at the upper and lower extremities and from paraspinal muscles reflect muscle relaxation similar to TOF testing. CONCLUSION: Hand TOF is superior to foot TOF in assessing muscle relaxation during spinal surgery. Hand TOF adequately represents the degree of muscle relaxation not only for the paraspinal muscles but also for all orthopaedic surgical sites where NMB is crucial for good surgical conditions. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03318718).

Treatment of hindfoot and ankle infections with Ilizarov external fixator or spacer, followed by secondary arthrodesis.

An established treatment strategy in surgical site infection after hindfoot and ankle surgery is a two-stage procedure with debridement and placement of a cement spacer, followed by antibiotic treatment and secondary arthrodesis. However, there is little evidence to favor this treatment over a one-stage procedure with debridement, followed by primary arthrodesis with an Ilizarov external fixator and antibiotic treatment. We compared the infection control and clinical and radiological outcome of a two-stage and a one-stage procedure. In this study, 7 patients with a two-stage revision and 11 patients with a one-stage revision between 2005 and 2015 were included. The primary outcome was infection control (absence of the Musculoskeletal Infection Society PJI criteria) 2 years after the ankle or hindfoot arthrodesis. Secondary outcome measures were the AOFAS hindfoot score and radiological consolidation rate. Infection control was 85% (6 out of 7 patients) in the two-stage group and 81% (9 out of 11 patients) in the one-stage group (p = 1.0). One patient (14%) of the two-stage and two patients (18%) in the one-stage group needed below-knee amputation. In the two-stage group, the mean postoperative AOFAS score was 74.8 (SD: ±11.3) versus 71.7 (SD: ±17.8) in the one-stage group. Radiological consolidation could be achieved in 71% in the spacer group (n = 5) and in 72% in the Ilizarov external fixator group (n = 9). Infection control, AOFAS score, and radiologic consolidation of hindfoot and ankle arthrodesis were comparable in both groups of patients with complicated postsurgical hindfoot or ankle infections.

Patellofemoral instability in trochleodysplastic knee joints and the quantitative influence of simulated trochleoplasty - A finite element simulation.

BACKGROUND: Patellofemoral instability is a debilitating condition mainly affecting young patients and has been correlated with trochlear dysplasia. It can occur when the patella is insufficiently guided through its range of motion. Currently, there is no literature describing patellofemoral stability in trochleodysplastic knees and the effect of isolated trochleoplasty on patellofemoral stability. METHODS: The effect of isolated trochleoplasty in trochleodysplastic knees of patients with symptomatic patellofemoral instability was investigated using a quasi-static finite element model. MRI data of five healthy knees were segmented, meshed and a finite element analysis was performed in order to validate the model. A second validation was performed by comparing simulated patellofemoral kinematics to in-vivo values obtained from upright- weight bearing CT scans. Subsequently, five trochleodysplastic knees were modelled before and after simulated trochleoplasty. The force necessary to dislocate the patella by 10 mm and to fully dislocate the patella was calculated in various knee flexion angles between 0 and 45°. FINDINGS: The developed models successfully predicted outcome values within the range of reference values from literature. Lateral stability was significantly lower in trochleodysplastic knees compared to healthy knees. Trochleoplasty was determined to significantly increase the force necessary to dislocate the patella in trochleodysplastic knees to comparable values as in healthy knees. INTERPRETATION: This is the first study to investigate lateral patellofemoral stability in patients with symptomatic patellofemoral instability and dysplasia of the trochlear groove. We confirm that patellofemoral stability is significantly lower in trochleodysplastic knees than in healthy knees. Trochleoplasty increases patellofemoral stability to levels similar to healthy.

The "Balgrist Score" for evaluation of Charcot foot: a predictive value for duration of off-loading treatment.

OBJECTIVE: To develop a new magnetic resonance imaging(MRI) scoring system for evaluation of active Charcot foot and to correlate the score with a duration of off-loading treatment ≥ 90 days. METHODS: An outpatient clinic database was searched retrospectively for MRIs of patients with active Charcot foot who completed off-loading treatment. Images were assessed by two radiologists (readers 1 and 2) and an orthopedic surgeon (reader 3). Sanders/Frykberg regions I-V were evaluated for soft tissue edema, bone marrow edema, erosions, subchondral cysts, joint destruction, fractures, and overall regional manifestation using a score according to degree of severity (0-3 points). Intraclass correlations (ICC) for interreader agreement and receiver operating characteristic analysis between MR findings and duration of off-loading-treatment were calculated. RESULTS: Sixty-five feet in 56 patients (34 men) with a mean age of 62.4 years (range: 44.5-85.5) were included. Region III (reader 1/reader 2: 93.6/90.8%) and region II (92.3/90.8%) were most affected. The most common findings in all regions were soft tissue edema and bone marrow edema. Mean time between MRI and cessation of off-loading-treatment was 150 days (range: 21-405). The Balgrist Score was defined in regions II and III using soft tissue edema, bone marrow edema, joint destruction, and fracture. Interreader agreement for Balgrist Score was excellent: readers 1/2: ICC 0.968 (95% CI: 0.948, 0.980); readers 1/2/3: ICC 0.856 (0.742, 0.917). A cutoff of ≥ 9.0 points in Balgrist Score (specificity 72%, sensitivity 66%) indicated a duration of off-loading treatment ≥ 90 days. CONCLUSION: The Balgrist Score is a new MR scoring system for assessment of active Charcot foot with excellent interreader agreement. The Balgrist Score can help to identify patients with off-loading treatment ≥ 90 days.

Os Acromiale in Reverse Total Shoulder Arthroplasty: A Cohort Study.

BACKGROUND: Increased passive deltoid tension after reverse total shoulder arthroplasty (RTSA) potentially leads to displacement or tilting of a preexisting os acromiale. PURPOSE: To analyze patients with an os acromiale who underwent RTSA and compare their outcomes and complications with a matched control group without an os acromiale. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: In this study, 45 shoulders in 42 patients with an os acromiale (cases) were matched to 133 patients without os acromiale (controls) who underwent RTSA between 2005 and 2016. The mean follow-up was 52 ± 32 months. Matching criteria included sex, type of surgery, duration of follow-up, and age. The Constant score (CS), Subjective Shoulder Value (SSV), and radiological outcomes were assessed postoperatively at 1-year, 2-year, and final follow-up visits. RESULTS: The mean CS, SSV, and range of motion improved from preoperative levels to the final follow-up in both groups (P < .01). Patients with an os acromiale had a relative CS of 70 ± 23 versus 76 ± 21 points (P = .15) and an SSV of 70 ± 30 versus 73 ± 24 (P = .52) compared with controls at the final follow-up visit. Patients with an os acromiale had significantly decreased active flexion of 104° ± 33° versus 114° ± 33° (P = .03) at 1 year and active abduction of 103° ± 37° versus 121° ± 38° at 2 years postoperatively (P = .02). A postoperatively painful os acromiale was found in 12 cases (27%) and spontaneously resolved in 8 cases after a mean of 33 months (range, 12-47 months; P = .04). CONCLUSION: RTSA reliably restores patient satisfaction despite the presence of an os acromiale, with a slightly impaired range of motion. Postoperative local tenderness at the os acromiale can be expected in 1 out of 4 patients, but this resolves spontaneously over time in the majority of patients.