Microfragmented abdominal adipose tissue-derived stem cells from knee osteoarthritis patients aged 29-65 years demonstrate in vitro stemness and low levels of cellular senescence.

Purpose: To investigate the level of cellular senescence in stem cells derived from microfragmented abdominal adipose tissue harvested from patients with knee osteoarthritis (OA). Methods: Stem cells harvested from microfragmented abdominal adipose tissue from 20 patients with knee OA, aged 29-65 years (mean = 49.8, SD = 9.58), were analysed as a function of patient age and compared with control cells exhibiting signs of cellular senescence. Steady-state mRNA levels of a panel of genes associated with senescence were measured by qPCR. Intracellular senescence-associated proteins p16 and p21, and senescence-associated ß-galactosidase activity were measured by flow cytometry. Cellular proliferation was assessed using a 5-ethynyl-2'-deoxyuridine proliferation assay. Stemness was assessed by stem cell surface markers using flow cytometry and the capacity to undergo adipogenic and osteogenic differentiation in vitro. Results: No correlation was found between cellular senescence levels of the microfragmented adipose tissue-derived stem cells and patient age for any of the standard assays used to quantify senescence. The level of cellular senescence was generally low across all senescence-associated assays compared to the positive senescence control. Stemness was verified for all samples. An increased capacity to undergo adipogenic differentiation was shown with increasing patient age (p = 0.02). No effect of patient age was found for osteogenic differentiation. Conclusions: Autologous microfragmented adipose tissue-derived stem cells may be used in clinical trials of knee OA of patients aged 29-65 years, at least until passage 4, as they show stemness potential and negligible senescence in vitro. Level of Evidence: Not applicable.

Clavicle fractures do not increase the occurrence of later subacromial pain syndrome. A registry-based case-control study with 15-25 years of follow-up of 131.838 persons from the Danish National Patient Register.

Background: A clavicle fracture often changes the mechanical axes of the shoulder girdle due to displacement and shortening, potentially leading to scapular protraction and decreased subacromial space. If protraction of the scapula is a major risk factor for developing subacromial pain syndrome (SAPS), a previous clavicle fracture could increase the risk of later SAPS. The purpose of this study was to investigate if a previous clavicle fracture correlates with a higher occurrence or earlier diagnosis of SAPS. Methods: In this retrospective case-control study with data from the Danish National Patient Register, all persons aged 18-60 years, with any hospital contact due to a clavicle fracture (DS420) between January 1, 1996, and December 31, 2005, were identified as cases. For each case, five controls, matched on age and sex, were identified. Primary outcome was the first hospital contact with a SAPS diagnosis (DM751-755) registered more than 180 days following the fracture. Follow-up was until November 01, 2021. Results: 21.973 cases and 109.865 controls were included. The incidence of clavicle fractures was 76 fractures per 100.000 persons per year. Twenty-three percent were female. 1.640 (7.46%) cases and 8.072 (7.35%) controls received a SAPS diagnosis within the following 15-25 years, demonstrating no significant difference in the occurrence of SAPS (P = .56). The mean time from fracture to SAPS diagnosis was shorter for cases compared to controls (4040 vs. 4442 days, P < .001), and cases were slightly younger when receiving the diagnosis (51.3 vs. 53.6 years, P < .001). 1614 cases underwent surgical fixation. This subgroup had a statistically significant higher occurrence of later SAPS diagnosis (205 cases, 13%, P < .001). Conclusions: Persons with a previous clavicle fracture did not have an increased occurrence of receiving a SAPS diagnosis compared to matched controls. However, the diagnosis was given 1-2 years earlier for people with a previous fracture. Based on these findings, no strong argument for protraction of the scapula as a major risk factor for the development of SAPS was found.

Adolescents with prior patellar dislocation report affected quality of life and function, as measured using the Banff Patella Instability Instrument, Kujala and EQ-5D-5L index scores.

PURPOSE: We aimed to establish patient-reported outcome measure (PROM) reference data for a cohort of patients with prior patellar dislocation without previous knee surgery. METHODS: All inhabitants of the Faroe Islands aged 15-19 years were sent an online survey via secure email to establish a national cohort. They were asked to answer questions regarding demographics, whether they had prior patellar dislocation and to complete the PROMs: the Banff Patella Instability Instrument (BPII), Kujala, Marx activity and EQ-5D-5L questionnaires. Participants who had undergone knee surgery were excluded. Participants who had prior patellar dislocation underwent radiographic examinations to diagnose trochlear dysplasia. The study included three cohorts: the general population, prior patellar dislocation and prior patellar dislocation and trochlear dysplasia cohorts. RESULTS: Of the 3749 individuals contacted, 1119 completed the survey and responded to at least one PROM. Of these, 102 reported a history of patellar dislocation and 57 of them had trochlear dysplasia. All PROMs, except the Marx score, reflected a worse quality of life and function after patellar dislocation than in the general population cohort; this was most pronounced in the BPII. The percentage of people experiencing problems in EQ-5D-5L dimensions was higher in the patellar dislocation and trochlear dysplasia cohorts than in the general population cohort in all EQ-5D-5L domains, except anxiety/depression. CONCLUSION: Adolescents who had patellar dislocation reported reduced quality of life and function according to the BPII, Kujala and EQ-5D-5L index values, as well as all EQ-5D-5L domains, except for anxiety/depression. However, their activity levels remained high. LEVEL OF EVIDENCE: Level III.

Three-dimensional measurements of scapular kinematics: Interrater reliability and validation of a skin marker-based model against an intracortical pin model.

A skin marker-based motion capture model providing measures of scapular rotations was recently developed. The aim of this study was to investigate the concurrent validity and the interrater reliability of the model. Shoulder range of motion (RoM) and activities of daily living (ADL) were tested in healthy volunteers with reflective markers on the scapula and thorax. To investigate the validity, the model was compared to simultaneous data collection from markers on a scapular intracortical pin. The interrater reliability was tested by comparing the skin marker-based protocol performed by two investigators. The mean root mean square error (RMSE) and the intraclass correlation coefficient (ICC(2,1)) were calculated to determine the validity and the interrater reliability, respectively. Eight subjects were included in the validity test: female/male = 2/6, mean (SD) age 35.0 (3.0) and BMI 23.4 (3.3). The mean RMSE of all scapular rotations ranged 2.3-6.7° during shoulder RoM and 2.4-7.6° during ADL. The highest errors were seen during sagittal and scapular plane flexions, hair combing and eating. The reliability test included twenty subjects: female/male = 8/12, mean (SD) age 31.4 (4.9) and BMI 22.9 (1.7). The ICC(2,1) for measuring protraction ranged 0.07-0.60 during RoM and 0.27-0.69 for ADL, for upward rotation the corresponding ICC(2,1) ranged 0.01-0.64 and 0.38-0.60, and anterior tilt 0.25-0.83 and 0.25-0.62. The validity and interrater reliability of the model are task dependent, and interpretation should be made with caution. The model provides quantitative measurements for objective assessment of scapular movements and can potentially supplement the clinical examination in certain motion tasks.

Return to badminton play following an ACL injury is common, but only a few return to previous performance.

PURPOSE: To report how many badminton players return to badminton after an anterior cruciate ligament (ACL) injury and to which level. METHODS: Patients in Denmark from 2000 to 2018, registered in the Danish National Patient Register with a diagnosis of ACL rupture and badminton as a primary sport were asked about a return to sport (RTS) and return to performance (RTP) after ACL injury. RTP was defined as the return to full participation in the same sport, same level and same preinjury performance. To investigate the likelihood of RTS and return to preinjury level, a binominal logistic regression was used. RESULTS: Badminton was the primary sport for 900 participants. Only 435 players were injured during badminton, and 626 participants intended to RTP. RTS was achieved by 396 (63%) and 117 (19%) returned to the same performance as their preinjury level. However, 273 (44%) returned to full participation at the same level as the preinjury level but did not perform as well. Males had a significantly higher RTS than females, and RTP was also higher among males [221 (68%) vs. 175 (58%), odds ratio, OR: 1.67, p = 0.003 and 74 (23%) vs. 43 (14%), OR: 1.58, p = 0.05]. CONCLUSION: Return to badminton was achieved by 396 (63%), but only 117 (19%) returned to the same performance as their preinjury level after ACL injury. Females are less successful in RTS and RTP. Future research on improving RTS and the RTP rates in badminton, in general, and specifically for females is needed. LEVEL OF EVIDENCE: Level II.

Acromioclavicular joint dislocation Rockwood type III and V show no difference in functional outcome and 91% recovered well without the need for surgery.

PURPOSE: Acromioclavicular (AC) joint dislocations are common injuries, but the indication for and timing of surgery is debated. The objective of the study was to evaluate the results after acute AC joint dislocations Rockwood type III and V treated nonsurgically with the option of delayed surgical intervention. METHODS: This is a prospective cohort study with clinical, radiological and patient-reported outcome assessment at baseline, 6 weeks, 3 months, 6 months and 1 year after acute AC joint dislocation. Patients aged 18-60 with acute AC joint dislocation and a baseline panorama (Zanca) radiograph with an increase in the coracoclavicular distance of >25% compared to the uninjured side were eligible for inclusion. All patients were treated nonsurgically with 3 months of home-based training and with the option of delayed surgical intervention. The primary outcome was the Western Ontario Shoulder Instability Index (WOSI). Secondary outcomes were surgery yes/no and the Shoulder Pain and Disability Index (SPADI). RESULTS: Ninety-five patients were included. Fifty-seven patients were Rockwood type III and 38 patients were type V. There were no statistically significant differences in WOSI and SPADI between patients with type III and V injuries at any time point. Nine patients (9.5%) were referred for surgery; seven type III and two type V (ns). CONCLUSION: Ninety-one percent of patients with acute AC joint dislocation Rockwood type III and V recovered without surgery and there were no differences in outcome scores between type III and V at any time point. LEVEL OF EVIDENCE: Level IV.

High prevalence of patellar dislocation and trochlear dysplasia in a geographically and genetically isolated society: an observational national cohort study from the Faroese Knee Cohort.

BACKGROUND AND PURPOSE: We aimed to calculate the prevalence of patellar dislocation (PD) and trochlear dysplasia (TD) in a national cohort aged 15-19 years in the Faroe Island. PATIENTS AND METHODS: All inhabitants in the Faroe Islands aged 15-19 years were invited to answer an online survey, including demographics and questions regarding prior PD. Participants with prior PD were invited for radiographs and MRI of both knees to be taken. Trochlear dysplasia was defined as one of the following: Dejour type A-D on radiographs, lateral trochlear inclination angle (LTI) < 11°, or trochlear depth < 3 mm on MRI. RESULTS: 3,749 individuals were contacted, 41 were excluded, and 1,638 (44%) completed the survey. 146 reported a prior PD (the PD cohort) and 100 accepted to participate and have radiographs and MRI taken of both knees (the clinical PD cohort), 76 of whom were diagnosed with TD. The national prevalence of PD was 8.9%. The national prevalence of symptomatic TD was 6.8%. The prevalence of TD in the clinical PD cohort was 76%. TD was bilateral in 78% of TD patients, but only 27% of patients with bilateral TD had PD in both knees. CONCLUSION: The prevalence of PD in the Faroe Islands is found to be very high. The national prevalence of TD and the prevalence of TD in participants with prior PD is high, indicating a potential genetic influence.

Anterior-posterior glenohumeral translation in shoulders with traumatic anterior instability: a systematic review of the literature.

Background: Reports of glenohumeral translation in shoulders with traumatic anterior instability have been presented. The aim of this systematic review was to investigate anterior-posterior translation in shoulders with traumatic anterior instability. Methods: This systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies including patients aged ≥15 years with previous traumatic anterior shoulder dislocation or subluxation were included. The outcome was anterior-posterior glenohumeral translation. A search of PubMed, Embase, and Cochrane library was performed on July 17, 2022. Two reviewers individually screened titles and abstracts, reviewed full text, extracted data, and performed quality assessment. Results: Twenty studies (582 unstable shoulders in total) of varying quality were included. There was a lack of standardization and unity across studies. Radiography, ultrasound, computed tomography, magnetic resonance imaging, motion tracking, instrumentation, and manual testing were used to assess the glenohumeral translation. The glenohumeral translation in unstable shoulders ranged from 0.0 ± 0.8 mm to 11.6 ± 3.7 mm, as measured during various motion tasks, arm positions, and application of external force. The glenohumeral translation was larger or more anteriorly directed in unstable shoulders than in stable when contralateral healthy shoulders or a healthy control group were included in the studies. Several studies found that the humeral head was more anteriorly located on the glenoid in the unstable shoulders. Conclusion: This systematic review provides an overview of the current literature on glenohumeral translation in traumatic anterior shoulder instability. It was not able to identify a threshold for abnormal translation in unstable shoulders, due to the heterogeneity of data. The review supports that not only the range of translation but also the direction hereof as well as the location of the humeral head on the glenoid seem to be part of the pathophysiology. Technical development and increased attention to research methodology in recent years may provide more knowledge and clarity on this topic in the future.

Effect of the Copenhagen Achilles Rupture Treatment Algorithm (CARTA) on Calf Muscle Volume and Tendon Elongation After Acute Achilles Tendon Rupture: A Predefined Secondary Analysis of the First 60 Patients in a Randomized Controlled Trial.

Background: Surgical treatment of acute Achilles tendon rupture (ATR) lowers the risk of rerupture and may reduce calf atrophy and elongation of the Achilles tendon. The Copenhagen Achilles Rupture Treatment Algorithm (CARTA) was developed to provide individualized treatment selection based on ultrasonographic evaluation of the rupture. Purpose: In a randomized setup, the present study aimed to investigate whether treatment selection using the CARTA could reduce atrophy and tendon elongation compared with (1) patients treated surgically and (2) patients treated nonsurgically. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: A total of 60 patients with an acute ATR were randomly assigned to receive treatment based on the CARTA (intervention), surgical treatment (control), or nonsurgical treatment (control) in a 1 to 1 to 1 ratio. After 1 year, magnetic resonance imaging of both calves was performed, and muscle volume and Achilles tendon length were measured. Results were presented as the ratio between the affected and the unaffected limbs (ie, limb symmetry index; %). Results: A total of 156 patients were assessed for eligibility, 60 patients were randomized, and 54 patients provided data for the study-19 patients received treatment based on the CARTA (intervention group), 17 patients received nonsurgical treatment (control), and 18 patients received surgical treatment (control). No statistically significant differences were found between the intervention group and the 2 control groups regarding muscle volume and tendon length. No statistically significant differences were found between patients treated surgically and patients treated nonsurgically. Comparison between the affected and the unaffected limb showed statistically significant muscle atrophy (24%-30%) and tendon elongation (soleus, 59%-76%; gastrocnemius, 8%-14%) in the affected limb in all 3 groups. Conclusion: Individualized treatment of acute ATR using an ultrasonographic selection algorithm did not reduce calf muscle atrophy or tendon elongation when compared with surgical and nonsurgical treatment. Surgical treatment did not reduce calf muscle atrophy or tendon elongation compared with nonsurgical treatment.

Interrater reliability of subacromial ultrasound measures in the hands of novice sonographers.

INTRODUCTION: Ultrasound measures of subacromial structures are reliable in the hands of experienced sonographers, but it remains unknown if inexperienced clinicians can achieve a satisfactory level of interrater reliability. The aim was to investigate if standardised subacromial ultrasound measures are reliable in the hands of novice sonographers. METHODS: Two novice sonographers performed standardised ultrasound measures on patients diagnosed with subacromial pain syndrome and asymptomatic shoulders. The measures were: supraspinatus tendon thickness (SUPRA), subacromial bursa thickness (SASD), acromio-humeral distance (AHD) and dynamic impingement (DI). Reliability and agreement were evaluated by intraclass correlation coefficient (ICC (2.1)), standard error of measurement, minimal detectable change, 95% limits of agreement, Bland-Altman plots and Cohen's unweighted κ. RESULTS: Twenty-eight patients were recruited (28 symptomatic and 20 asymptomatic shoulders). The ICC of SUPRA ranged from 0.73 to 0.77. The ICC of SASD ranged from 0.41 to 0.88 and AHD from 0.68 to 0.72. Cohen's κ of DI in symptomatic shoulders was 0.29. CONCLUSION: The interrater reliability of novice sonographers was found to be moderate to good when assessing SUPRA and AHD. For SASD and DI, the reliability ranged from poor to good. No significant differences in SUPRA and SASD thickness were found between symptomatic and asymptomatic shoulders. FUNDING: None. TRIAL REGISTRATION: Not relevant.

Rockwood type III is the most common type of acromioclavicular joint dislocation: A prospective cohort study investigating the incidence and epidemiology of acute acromioclavicular joint dislocations in an urban population.

Introduction: Acromioclavicular (AC) joint dislocations are common, but basic epidemiological features and sub-classification are not well investigated. The aim of the study was to investigate the incidence and epidemiology of acute AC joint dislocations in the capital region of Denmark. Methods: All patients with acute AC joint dislocation admitted to the emergency departments at 3 University Hospitals serving a population of 549,225 residents were prospectively registered from January to December 2019. Patients with trauma to the shoulder, pain from the AC joint and increased coracoclavicular distance on radiographs were included and classified according to Rockwood's classification. Data on age, sex and mechanism of injury were registered. Results: A total of 106 patients, male:female ratio 8.6:1, were included. Rockwood type III was most common accounting for 59/106(55.7%) of the injuries. The incidence was 19.3 per 100,000 person-years at risk (PYRS). The age distribution was bimodal peaking at the ages of 20-24 and 55-59 years. The most common mechanism of injury was sports, 80/106, with cycling accounting for 51/106. Discussion/Conclusion: Rockwood type III was the most common type of AC joint dislocation constituting 55.7% of the injuries. The incidence was 19.3 per 100,000 PYRS. Young and middle-aged males were at highest risk and most injuries occurred during sports.

Morel-Lavallée lesion.

Morel-Lavallée lesion (MLL) is a closed degloving injury caused by traumatic sheering of subcutaneous tissue from the underlying fascia. MLL can be classified as acute (less-than 3 months) or chronic (greater-than 3 months or if a capsule has formed). Acute lesions are treated with compression, percutaneous aspiration, sclerodesis, suction-curettage or open surgery depending on vitality of the overlying skin, if fractures are present next to the lesion or if infection has occurred. Chronic lesions are treated with sclerodesis, suction-curettage or open surgery. Drain and vacuum-assisted closure placement should be used post-operatively, as argued in this review.

Achilles Tendon Tissue Turnover Before and Immediately After an Acute Rupture.

BACKGROUND: An Achilles tendon rupture (ATR) is a frequent injury and results in the activation of tendon cells and collagen expression, but it is unknown to what extent turnover of the tendon matrix is altered before or after a rupture. PURPOSE/HYPOTHESIS: The purpose of this study was to characterize tendon tissue turnover before and immediately after an acute rupture in patients. It was hypothesized that a rupture would result in pronounced collagen synthesis in the early phase (first 2 weeks) after the injury. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: The study included patients (N = 18) eligible for surgery after an ATR. At the time of inclusion, the patients ingested deuterium oxide (2H2O) orally, and on the day of surgery (within 14 days of the injury), they received a 3-hour flood-primed infusion of an 15N-proline tracer. During surgery, the patients had 1 biopsy specimen taken from the ruptured part of the Achilles tendon and 1 that was 3 to 5 cm proximal to the rupture as a control. The biopsy specimens were analyzed for carbon-14 (14C) levels in the tissue to calculate long-term turnover (years), incorporation of 2H-alanine (from 2H2O) into the tissue to calculate the fractional synthesis rate (FSR) of proteins in the short term (days), and incorporation of 15N-proline into the tissue to calculate the acute FSR (hours). RESULTS: Both the rupture and the control samples showed consistently lower levels of 14C compared with the predicted level of 14C in a healthy tendon, which indicated increased tendon turnover in a fraction (48% newly synthesized) of the Achilles tendon already for a prolonged period before the rupture. Over the first days after the rupture, the synthesis rate for collagen was relatively constant, and the average synthesis rate on the day of surgery (2-14 days after the rupture) was 0.025% per hour, irrespective of the length of time after a rupture and the site of sampling (rupture vs control). No differences were found in the FSR between the rupture and control samples in the days after the rupture. CONCLUSION: Higher than normal tissue turnover in the Achilles tendon before a rupture indicated that changes in the tendon tissue preceded the injury. In addition, we observed no increase in tendon collagen tissue turnover in the first 2 weeks after an ATR. This favors the view that an increase in the formation of new tendon collagen is not an immediate phenomenon during the regeneration of ruptured tendons in patients. REGISTRATION: NCT03931486 (ClinicalTrials.gov identifier).

Interrater and intrarater reliability of four different classification methods for evaluating acromial morphology on standardized radiographs.

Background: Acromial morphology is an important pathophysiological factor for the development of subacromial impingement syndrome. There are 3 radiological methods to evaluate acromial morphology: Bigliani, modified Epstein, and acromial angle. However, their reliability have not been compared in a single study, nor using standardized radiographs. Consequently, the evaluation of acromial morphology is currently not validated though its widespread use across the world. The objective of this study was to investigate reliability of the 3 known classifications and the novel Copenhagen Acromial Curve classification. Methods: Three experienced clinicians rated 102 standardized supraspinatus outlet view radiographs with the 4 classification methods in 2 separate sessions a month apart. All measurements were blinded. With an expected kappa (κ) and intraclass correlation coefficient (ICC) > 0.7 (+/-0.15), the target sample size was 87 radiographs. Results: The Bigliani classification had interrater and intrarater reliability ranging from fair to good (κ 0.32-0.41 and 0.26-0.62). The modified Epstein classification had fair to good interrater and intrarater reliability (κ 0.24-0.69 and 0.57-0.63). The acromial angle classification had moderate to good interrater and intrarater reliability (κ 0.53-0.60 and 0.59-0.72). The novel Copenhagen Acromial Curve classification showed moderate to good interrater and intrarater reliability (ICC 0.66-0.71 and 0.75-0.78, respectively). Conclusion: The Copenhagen Acromial Curve was the only classification method with an ICC value > 0.7. The popular Bigliani classification had the worst reliability. The Copenhagen Acromial Curve classification produces numerical data, as opposed to the other 3 classification methods. This could potentially be utilized in future research to establishing cut-off values for treatment stratification.

Trochlear Shape and Patient-Reported Outcomes After Arthroscopic Deepening Trochleoplasty and Medial Patellofemoral Ligament Reconstruction: A Retrospective Cohort Study Including MRI Assessments of the Trochlear Groove.

Background: Sparse objective data are available documenting changes of trochlear shape after trochleoplasty. Purpose/Hypothesis: The purpose was to investigate whether standardized magnetic resonance imaging (MRI) measurements that characterize trochlear dysplasia (TD) change significantly after arthroscopic deepening trochleoplasty (ADT) combined with medial patellofemoral ligament (MPFL) reconstruction. It was hypothesized that MRI measurements would approximate normal values. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent ADT between October 2014 and December 2017 were considered for this study. The preoperative inclusion criteria for ADT surgery were patellar instability, a dynamic patellar apprehension sign at 45° of flexion, a lateral trochlear inclination (LTI) angle of <11°, and failed physical therapy. MRI was performed pre- and postoperatively, and standardized MRI measurements were calculated: LTI angle, trochlear depth, trochlear facet asymmetry, cartilage thickness, and trochlear height. The Banff Patella Instability Instrument 2.0 (BPII) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Kujala score were obtained pre- and postoperatively. Results: A total of 16 knees in 15 patients (12 female and 3 male; median age, 20.9 years; range, 14.1-51.3 years) were evaluated. The mean follow-up time was 63.6 months (range, 23-97 months). The median LTI angle improved from 1.25° (range, -25.1° to 10.6°) preoperatively to 10.7° (range, -17.7° to 25.8°) postoperatively (P < .001), trochlear depth increased from 0.0 mm (range, -4.2 to 1.8 mm) to 3.23 mm (range, 0.25-5.3 mm) (P < .001), and trochlear facet asymmetry improved from 4.55% (range, 0.0%-28.6%) to 17.8% (range, 0.0%-55.6%) (P < .003). Cartilage thickness was unchanged: 4.5 mm (range, 1.9-7.4 mm) preoperatively and 4.9 mm (range, 0.6-8.3 mm) postoperatively (P = .796). BPII, KOOS, and Kujala scores improved significantly (P < .0034 for all). Conclusion: Combined ADT and MPFL reconstruction led to statistically significant and clinically relevant improvements in patient-reported outcomes and standardized MRI measurements that characterize TD. The improvements corresponded to those obtained by open trochleoplasty. No significant reduction in cartilage thickness was seen.

Successful isolation of viable stem cells from cryopreserved microfragmented human adipose tissue from patients with knee osteoarthritis - a comparative study of isolation by tissue explant culture and enzymatic digestion.

PURPOSE: To investigate if viable stem cells could be isolated and expanded from cryopreserved microfragmented adipose tissue (AT) harvested from patients with knee osteoarthritis. METHODS: Microfragmented abdominal AT from knee osteoarthritis patients was cryopreserved at -80 °C in cryoprotectant-medium. The samples were thawed for stem cell isolation by tissue explant culture (TEC) and enzymatic digestion (ED), respectively. Viability, population doublings, and doubling time were assessed by trypan blue staining and flow cytometry. Cell type and senescence-associated ß-galactosidase activity were analyzed by flow cytometry. Osteogenic and adipogenic differentiation was assessed quantitatively by Alizarin-Red-S and Oil-Red-O staining, respectively. RESULTS: Microfragmented AT from 7 patients was cryopreserved for a period of 46-150 days (mean (SD) 115.9 days (44.3 days)). Viable stem cells were successfully recovered and expanded from all patients using both isolation methods with no significant difference in viable population doublings or doubling time from passage 1 to 3 (p > 0.05). Low levels of senescence-associated ß-galactosidase activity was detected for both methods with no significant difference between TEC and ED (p = 0.17). Stemness was verified by stem cell surface markers and osteogenic and adipogenic differentiation performance. Adventitial stem cells (CD31-CD34+CD45-CD90+CD146-), pericytes (CD31-CD34-CD45-CD90+CD146+), transitional pericytes (CD31-CD34+CD45-CD90+CD146+), and CD271+ stem cells (CD31-CD45-CD90+CD271+) were identified using both methods. More pericytes were present when using TEC (25% (24%)) compared to ED (3% (2%)) at passage 4 (p = 0.04). CONCLUSIONS: Viable stem cells can be isolated and expanded from cryopreserved microfragmented AT using both TEC and ED. TEC provides more clinically relevant pericytes than ED.

Trochlea dysplasia, increased TT-TG distance and patella alta are risk factors for developing first-time and recurrent patella dislocation: a systematic review.

PURPOSE: The aim of the study was to perform a systematic review and best knowledge synthesis of the present literature concerning biomechanical risk factors for developing first-time and recurrent patella dislocation. METHODS: The study was performed as a systematic review following PRISMA guidelines. PubMed and EMBASE were systematically searched. Studies investigating participants with risk factors for first-time as well as recurrent patella dislocation were included. The records were screened, and data extracted independently by two researchers supervised by a third independent assessor. The study was registered in PROSPERO. RESULTS: A total of 6233 records were screened, and 50 studies met the inclusion criteria. The biomechanical risk factors: trochlear dysplasia, increased tibial tuberosity-trochlear groove distance (TT-TG), and patella alta were found to be statistically significantly associated with patella dislocation in several publications and were thus recognized as risk factors for patella dislocation. The soft-tissue stabilizers: longer and thinner MPFL ligament, increased number of type 2C and decreased number of type 1 muscle fibers, and joint laxity were found to be statistically significantly associated with patella dislocation in a few publications, but due to limited evidence, no conclusion was made on this matter. CONCLUSION: There is strong evidence in the literature that abnormalities of bony stabilizers, trochlear dysplasia, increased TT-TG distance, and patella alta are risk factors for patella dislocation. There is less evidence that soft-tissue stabilizers are risk factors. The study emphasizes the importance of a thorough investigation of bony stabilizers in clinical decision-making. LEVEL OF EVIDENCE: Level IV.

Terminology and diagnostic criteria used in studies investigating patients with subacromial pain syndrome from 1972 to 2019: a scoping review.

INTRODUCTION: There is no recognised terminology, nor diagnostic criteria, for patients with subacromial pain syndrome (SAPS). This is likely to cause heterogeneity across patient populations. This could be a driver of misconceptions and misinterpretations of scientific results. We aimed to map the literature regarding terminology and diagnostic criteria used in studies investigating SAPS. MATERIALS AND METHODS: Electronic databases were searched from inception to June 2020. Original peer-reviewed studies investigating SAPS (also known as subacromial impingement or rotator cuff tendinopathy/impingement/syndrome) were eligible for inclusion. Studies containing secondary analyses, reviews, pilot studies and studies with less than 10 participants were excluded. RESULTS: 11 056 records were identified. 902 were retrieved for full-text screening. 535 were included. 27 unique terms were identified. Mechanistic terms containing 'impingement' are used less than before, while SAPS is used increasingly. For diagnoses, combinations of Hawkin's, Neer's, Jobe's, painful arc, injection test and isometric shoulder strength tests were the most often used, though this varied considerably across studies. 146 different test combinations were identified. 9% of the studies included patients with full-thickness supraspinatus tears and 46% did not. CONCLUSION: The terminology varied considerably across studies and time. The diagnostic criteria were often based on a cluster of physical examination tests. Imaging was primarily used to exclude other pathologies but was not used consistently. Patients with full-thickness supraspinatus tears were most often excluded. In summary, studies investigating SAPS are heterogeneous to an extent that makes it difficult, and often impossible, to compare studies.

Familial association and epidemilogical factors as risk factors for developing first time and recurrent patella dislocation: a systematic review and best knowledge synthesis of present literature.

PURPOSE: The aim of our study was to perform a systematic review and best knowledge synthesis of the present literature concerning the familial association and epidemiological factors as risk factors for developing first-time and recurrent patella dislocation. METHODS: The study was conducted according to the PRISMA guidelines and registered in PROSPERO. EMBASE and PubMed were systematically searched on the 5th of May 2022. Studies investigating participants with genetic and epidemiological risk factors for the first time as well as recurrent patella dislocation were included. The records were screened, and data were extracted independently by two researchers supervised by a third independent assessor. RESULTS: A total of 6,649 records were screened, and 67 studies were included. Familial association was described as a risk factor for patella dislocation in 17 studies. One study found that participants with a family history of patella dislocation had a 3.7 higher risk for patella dislocation in the contralateral asymptomatic knee, and another study found a family history of PD in 9% of 74 participants. Eleven studies found an accumulation of patella dislocation across generations in specific families. Additionally, a range of genetic syndromes was associated with patella dislocation. Young age is a well-investigated risk factor for patella dislocation, but the results are inconsistent. Only five and eight studies investigated skeletal immaturity and gender as risk factors for patella dislocation, respectively. CONCLUSION: There may be a familial association with patella dislocation, but further investigation is necessary to determine the strength and etiology of the association. There is weak evidence that epidemiological risk factors, such as age, skeletal immaturity, gender, and BMI are risk factors for patella dislocation. LEVEL OF EVIDENCE: IV.