Breaking the optical efficiency limit of virtual reality with a nonreciprocal polarization rotator

A catadioptric lens structure,also known as pancake lens,has been widely used in virtual reality(VR)displays to reduce the formfactor.However,the utilization of a half mirror(HM)to fold the optical path thrice leads to a significant optical loss.The theoretical maximum optical efficiency is merely 25%.To transcend this optical efficiency constraint while retaining the foldable characteristic inherent to traditional pancake optics,in this paper,we propose a theoretically lossless folded optical system to replace the HM with a nonreciprocal polarization rotator.In our feasibility demonstration experiment,we used a commercial Faraday rotator(FR)and reflective polarizers to replace the lossy HM.The theoretically predicted 100%efficiency can be achieved approximately by using two high-extinction-ratio reflective polarizers.In addition,we evaluated the ghost images using a micro-OLED panel in our imaging system.Indeed,the ghost images can be suppressed to undetectable level if the optics are with antireflection coating.Our novel pancake optical system holds great potential for revolutionizing next-generation VR displays with lightweight,compact formfactor,and low power consumption.

Degradable magnesium alloy suture promotes fibrocartilaginous interface regeneration in a rat rotator cuff transosseous repair model

Despite transosseous rotator cuff tear repair using sutures is widely accepted for tendon-bone fixation,the fibrocartilaginous enthesis regeneration is still hardly achieved with the traditional sutures.In the present work,degradable magnesium(Mg)alloy wire was applied to suture supraspinatus tendon in a rat acute rotator cuff tear model with Vicryl Plus 4±0 absorbable suture as control.The shoulder joint humerus-supraspinatus tendon complex specimens were retrieved at 4,8,and 12 weeks after operation.The Mg alloy suture groups showed better biomechanical properties in terms of ultimate load to failure.Gross observation showed that hyperplastic response of the scar tissue at the tendon-bone interface is progressively alleviated over time in the both Mg alloy suture and Vicryl suture groups.In the histological analysis,for Mg alloy suture groups,chondrocytes appear to proliferate at 4 weeks postoperatively,and the tendon-bone interface showed an orderly structural transition zone at 8 weeks postoperatively.The collagenous fiber tended to be aligned and the tendon-bone interlocking structures apparently formed,where transitional structure from unmineralized fibrocartilage to mineralized fibrocartilage was closer to the native fibrocartilaginous enthesis.In vivo degradation of the magnesium alloy wire was completed within 12 weeks.The results indicated that Mg alloy wire was promising as degradable suture with the potential to promotes fibrocartilaginous interface regeneration in rotator cuff repair.

Ultrasound of the Rotator Cuff in Non-Fractured Shoulder Trauma: 30 Cases at the Yalgado Ouedraogo University Hospital of Ouagadougou (Burkina Faso)

Introduction: Ultrasound is the imaging technique of choice for the study of rotator cuff lesions. However, in the case of shoulder trauma, it is rarely requested in our context. This study aimed to show ultrasound lesions of the rotator cuff in cases of non-fracture shoulder trauma at the CHUYO in Ouagadougou. Methodology: This was a prospective descriptive cross-sectional study running from August 1 to November 30, 2017, in the medical imaging department of CHUYO. The study population consisted of patients received in the department for ultrasound in the context of non-fracture shoulder trauma. Results: We collected 20 cases (66.67%) of rotator cuff lesions out of 30 non-fracture shoulder injuries. The mean age of the patients was 27.6 years. Road traffic accidents accounted for 60% of injuries, sports accidents for 30%, and domestic accidents for 10%. Ultrasound lesions were mainly tendon ruptures (36.67%) and tendinitis (23.33%). Ruptures were non-transfixing in 90.90% of cases. The supraspinatus was the most affected (81.81%). Conclusion: Ultrasound can help diagnose rotator cuff injuries, particularly in non-fractured shoulder trauma.

Long head of biceps tendon transposition for massive and irreparable rotator cuff tears:A systematic review and meta-analysis

BACKGROUND Superior capsular reconstruction(SCR)with long head of biceps tendon(LHBT)transposition was developed to massive and irreparable rotator cuff tears(MIRCTs);however,the outcomes of this technique remain unclear.AIM To perform a systematic review of biomechanical outcomes and a meta-analysis of clinical outcomes after LHBT transposition for MIRCTs.METHODS We performed a systematic electronic database search on PubMed,EMBASE,and Cochrane Library.Studies of SCR with LHBT transposition were included according to the inclusion and exclusion criteria.Biomechanical studies were assessed for main results and conclusions.Included clinical studies were evaluated for quality of methodology.Data including study characteristics,cohort demographics,and outcomes were extracted.A meta-analysis was conducted of the clinical outcomes.RESULTS According to our inclusion and exclusion criteria,a total of six biomechanical studies were identified and reported an overall improvement in subacromial contact pressures and prevention of superior humeral migration without limiting range of motion(ROM)after LHBT transposition for MIRCTs.A total of five clinical studies were included in the meta-analysis of LHBT transposition outcomes,consisting of 253 patients.The results indicated that compared to other surgical methods for MIRCTs,LHBT transposition had advantages of more significant improvement in ROM(forward flexion mean difference[MD]=6.54,95%confidence interval[CI]:3.07-10.01;external rotation[MD=5.15,95%CI:1.59-8.17];the acromiohumeral distance[AHD][MD=0.90,95%CI:0.21-1.59])and reducing retear rate(odds ratio=0.27,95%CI:0.15-0.48).No significant difference in American Shoulder and Elbow Surgeons score,visual analogue scale score,and University of California at Los Angles score was demonstrated between these two groups for MIRCTs.CONCLUSION In general,SCR with LHBT transposition was a reliable and economical technique for treating MIRCTs,both in terms of biomechanical and clinical outcomes,with comparable clinical outcomes,improved ROM,AHD,and reduced the retear rates compared to conventional SCR and other established techniques.More high-quality randomized controlled studies on the long-term outcomes of SCR with LHBT transposition are required to further assess.

Rotator cuff repair with an interposition polypropylene mesh:A biomechanical ovine study

BACKGROUND Chronic large to massive rotator cuff tears are difficult to treat and re-tears are common even after surgical repair.We propose using a synthetic polypropylene mesh to increase the tensile strength of rotator cuff repairs.We hypothesize that using a polypropylene mesh to bridge the repair of large rotator cuff tears will increase the ultimate failure load of the repair.AIM To investigate the mechanical properties of rotator cuff tears repaired with a polypropylene interposition graft in an ovine ex-vivo model.METHODS A 20 mm length of infraspinatus tendon was resected from fifteen fresh sheep shoulders to simulate a large tear.We used a polypropylene mesh as an interposition graft between the ends of the tendon for repair.In seven specimens,the mesh was secured to remnant tendon by continuous stitching while mattress stitches were used for eight specimens.Five specimens with an intact tendon were tested.The specimens underwent cyclic loading to determine the ultimate failure load and gap formation.RESULTS The mean gap formation after 3000 cycles was 1.67 mm in the continuous group,and 4.16 mm in the mattress group(P=0.001).The mean ultimate failure load was significantly higher at 549.2 N in the continuous group,426.4 N in the mattress group and 370 N in the intact group(P=0.003).CONCLUSION The use of a polypropylene mesh is biomechanically suitable as an interposition graft for large irreparable rotator cuff tears.

Effects of different positions on rehabilitation after rotator cuff repair under shoulder arthroscopy

Objective Shoulder arthroscopic rotator cuff tear repair is currently the main treatment for full-thickness rotator cuff tears,and postoperative rehabilitation training is essential.However,pain and limitation of activity during the rehabilitation process will lead to poor results.Hence,identifying rehabilitation approaches is crucial.This study aimed to compare patient's rehabilitation outcomes and experience between rehabilitation in the supine position and in the standing position.Methods This prospective study included patients diagnosed with full-thickness rotator cuff tears who underwent shoulder arthroscopic double-row rivet repair at Sir Run Run Shaw Hospital,Zhejiang University School of Medicine from March 2019 to September 2021.The patients were randomly assigned to the standing rehabilitation exercise group(group A)and the supine rehabilitation exercise group(group B).All patients were followed up for 6 months to record and compare the visual analog scale(VAS)scores,shoulder range of motion,and rehabilitation compliance.Results Altogether,86 patients participated in the study,of whom 79 patients completed the 6-month follow-up.Groups A and B had 39 and 40 patients,respectively.Before operation,the VAS score,forward flexion and extension angle,and abduction angle were comparable between groups A and B.After operation,the patients in groups A and B all experienced a significant improvement in the VAS score,forward flexion and extension angle,and abduction angle(p<0.05).In addition,patients in group B had better VAS score(4.58±0.87 vs.5.21±1.13,p=0.0068;2.15±0.66 vs.2.51±0.51,p=0.0078;0.78±0.86 vs.1.33±0.81,p=0.0015),forward flexion and extension angle(109.30±2.87°vs.102.33±3.74°,p=0.0001;109.53±3.39°vs.104.18±2.76°,p=0.0001;125.22±6.05°vs.117.59±2.27°,p=0.0001),and abduction angle(91.78±2.77°vs.82.92±2.12°,p=0.0001;91.62±2.78°vs.82.82±1.45°,p=0.0001;109.48±3.37°vs.100.10±2.94°,p=0.0001)at 2 wk,6 wk and 6 m postoperatively.Conclusion After 6 months of follow-up,the patients who performed rehabilitation exercises in the supine position achieved better rehabilitation outcomes than those who performed rehabilitation exercises while standing.

Role of platelet-rich plasma in the treatment of rotator cuff tendinopathy

Shoulder pain is a common musculoskeletal complaint,and rotator cuff(RC)pathologies are one of the main causes.The RC undergoes various tendinopathic and avascular changes during the aging process.Other degenerative changes affecting its healing potential make it an appealing target for biological agents.Platelet-rich plasma(PRP)has demonstrated the potential to deliver a high concentration of several growth factors and anti-inflammatory mediators,and its clinical use is mainly supported by experiments that demonstrated its positive effect on muscle,ligaments,and tendinous cells.This review aimed to specify the role of PRP and its future applications in RC tendinopathies based on the current clinical evidence.Due to the different characteristics and conflicting outcomes,clinicians should use PRP with moderate expectations until more consistent evidence is available.However,it is reasonable to consider PRP in patients with contraindications to corticosteroid injections or those with risk factors for inadequate healing.Its autologous origin makes it a safe treatment,and its characteristics make it a promising option for treating RC tendinopathy,but the efficacy has yet to be established.

Bilateral dislocation of the long head of biceps tendon with intact rotator cuff tendon:A case report

BACKGROUND Dislocation of the long head of biceps tendon(LHBT)usually involves rotator cuff injury,and isolated dislocation with an intact rotator cuff is rare.Some cases of isolated dislocation have been reported.However,to the best of our knowledge,there has been no report of bilateral dislocation of the LHBT without rotator cuff pathology.CASE SUMMARY A 23-year-old male presented to our outpatient clinic with left side dominant pain in both shoulders.The patient had no history of trauma or overuse.The patient underwent intra-articular injection and physical therapy,but his symptoms aggravated.Based on preoperative imaging,the diagnosis was bilateral dislocation of the LHBT.Dysplasia of the bicipital groove was detected in both shoulders.Active dislocation of the biceps tendon over an intact subscapularis tendon was identified by diagnostic arthroscopy.Staged biceps tenodesis was performed and continuous passive motion therapy was administered immediately after surgery.The patient’s pain was resolved,and full functional recovery was achieved,and he was satisfied with the condition of his shoulders.CONCLUSION This study describes a rare case of bilateral dislocations of the LHBT without rotator cuff injury due to dysplasia of the bicipital groove.

Clinical Decision Making in Open vs Arthroscopic Rotator Cuff Repair: Evidence for Preoperative Decision Making

Objective: To further understand what factors should be considered when deciding to do mini-open versus arthroscopic rotator cuff repair. Methods: A systematic literature search on the computer was done with the help of the PubMed database. Of the articles searched through, three have been chosen to specifically address topics of interest concerning the factors affecting arthroscopic vs mini-open RCR surgical approaches. Discussion: As we continue to progress down the line of factors impacting a clinician’s decision making, we begin to see how postoperative management is unchanged. Tear severity lacks sufficient evidence to base a decision on, but financial, educational, and logistical factors are proven to play a significant role in this decision. Conclusion: As of right now it seems that mini-open RCR is the most cost and time efficient method, especially amongst non-fellowship trained surgeons or ones with lower volume of shoulder scopes. However, further studies should be done to examine cost and efficiency in Sport Medicine fellowship trained orthopedic surgeons to validate these findings.

Outcomes after arthroscopic repair of rotator cuff tears in the setting of mild to moderate glenohumeral osteoarthritis

BACKGROUND Rotator cuff pathology is a very common source of shoulder pain.Similarly,osteoarthritis of the glenohumeral joint can cause shoulder pain and produce similar symptoms.Surgical management can be indicated for both pathologies,however,outcomes data is limited when examining rotator cuff repair(RCR) in the setting of glenohumeral arthritis(GHOA).Thus,this study sought to determine outcomes for patients who undergo RCR in the setting of GHOA.AIM To evaluate if a relationship exists between outcomes of RCR in the setting of GHOA.METHODS This was a retrospective analysis of patients who underwent arthroscopic rotator cuff repair with concurrent glenohumeral osteoarthritis between 2010-2017.Patients were stratified based on rotator cuff tear size and glenohumeral osteoarthritis severity.Cohorts were paired 1:1 with patients without glenohumeral osteoarthritis.Patients included had a minimum two year follow-up.Rate of conversion to total shoulder arthroplasty,complication rates following initial surgery,and patient-reported outcome measures were collected.RESULTS A total of 142 patients were included.The number of patients that required total shoulder arthroplasty within two years after index surgery was low.2/71(2.8%) patients with GHOA,and 1/71(1.4%) without GHOA.Following rotator cuff repair,both groups showed favorable patientreported outcomes.CONCLUSION Patients with glenohumeral osteoarthritis who underwent arthroscopic rotator cuff repair showed comparable outcomes to patients without glenohumeral osteoarthritis.

Comparison with Surgical Findings for the Accuracy of Routine MRI in Rotator Cuff Tears

Objective: To evaluate the diagnostic efficacy of magnetic resonance imaging (MRI) for the detection of partial-thickness rotator cuff tears (PTT) and full-thickness rotator cuff tears(FTT) by comparing its findings with surgical findings as the gold standard and to improve the previous MRI accuracy in diagnosing rotator cuff tears (RCT) considering more variables. Methods: In 45 months, 804 patients underwent MRI shoulder joint. Among them, only 95 cases had undergone both MRI imaging and surgery accordingly. The patient records were evaluated retrospectively if MRI and surgery were performed within 40 days of MRI. MRI findings were categorized into PTT, FTT and no tears which were further divided into different types according to four main nominal data as variables viz. site, size, shape and muscle involvement in RCT and were correlated with surgical findings for statistical calculation by using Kappa coefficient and McNemar Bowker test. Results: 81 patients (86 RCTs) underwent surgery within 40 days. On the basis of site as variable, MRI correctly depicted 100% of full thickness tears(FTT), 85% of bursal partial thickness tears(PTT), 80.4% of articular partial thickness tears(PTT). The consistency in diagnosis of RCT between MRI and surgery was moderate (Kappa coefficient 0.645). Overall sensitivity, specificity and accuracy of MRI for diagnosing PTT was 87.3%, 53.3% and 81.3%;and that for FTT was 100%, 98.7% and 98.8% respectively. Likewise on the basis of size, shape and muscles involved, the consistency between MRI and surgery was poor for size and shape and moderate for muscles involved;and the difference in diagnosing RCT by MRI and surgery was significant for shape (P = 0.002) only, but not significant for size (P = 0.16) and for muscles involved (P = 0.206) respectively. The agreement between MRI and surgery in diagnosing calcific tendinitis and shoulder joint hematoma with Kappa coefficient is (0.577) and (0.556) respectively. Conclusion: MRI has better accuracy for detecting FTT and has high sensitivity and positive predictive value in diagnosing both PTT and FTT. Combining more others variables in addition to RCT, MRI offers a great value in diagnosing RCT.

Accuracy of the rotator cuff reparability score

BACKGROUND The reparability of large or massive rotator cuff tears is difficult to determine preoperatively.We previously identified age≥65 years,acromiohumeral interval≤6 mm,and anteroposterior tear size≥22 mm as risk factors for rotator cuff repair failure.We therefore developed a rotator cuff reparability score where each of the above risk factors is assigned a score of one point.AIM To determine the accuracy of a rotator cuff reparability score.METHODS This was a retrospective cohort study of recruited patients with large or massive rotator cuff tears treated at our institution between January 2013 and December 2019.Exclusion criteria were revision surgery and patients with contraindications for surgery.All patients underwent arthroscopic rotator cuff repair and were categorized into either complete or partial rotator cuff repair.Rotator cuff reparability scores were calculated for each patient.The sensitivity,specificity,positive and negative predictive value,and positive and negative likelihood ratio were assessed.A receiver operating characteristic curve was plotted to determine the optimal cut-off rotator cuff reparability score.RESULTS Eighty patients(mean age,61 years;range,25–84 years;41 females and 39 males)were recruited.Intra-and inter-observer reliabilities were good to excellent.The number of patients with 0,1,2,and 3 risk factors for rotator cuff repair failure were 24,33,17,and 6,respectively.Complete repair was performed in all patients without risk factors.Two of the 33 patients with one risk factor and seven of the 17 patients with two risk factors underwent partial repair.One of the six patients with three risk factors underwent complete repair.The area under the curve was 0.894.The optimal cut-off score was two points with a sensitivity of 85.71%and a specificity of 83.33%.CONCLUSION A rotator cuff reparability score of two was determined to be the optimal cut-off score for predicting the reparability of large or massive rotator cuff tears.

Factors affecting healing after arthroscopic rotator cuff repair

Rotator cuff repair has been shown to have good longterm results. Unfortunately, a significant proportion of repairs still fail to heal. Many factors, both patient and surgeon related, can influence healing after repair. Older age, larger tear size, worse muscle quality, greater muscle-tendon unit retraction, smoking, osteoporosis, diabetes and hypercholesterolemia have all shown to negatively influence tendon healing. Surgeon related factors that can influence healing include repair construct-single vs double row, rehabilitation, and biologics including platelet rich plasma and mesenchymalstem cells. Double-row repairs are biomechanically stronger and have better healing rates compared with single-row repairs although clinical outcomes are equivalent between both constructs. Slower, less aggressive rehabilitation programs have demonstrated improved healing with no negative effect on final range of motion and are therefore recommended after repair of most full thickness tears. Additionally no definitive evidence supports the use of platelet rich plasma or mesenchymal stem cells regarding improvement of healing rates and clinical outcomes. Further research is needed to identify effective biologically directed augmentations that will improve healing rates and clinical outcomes after rotator cuff repair.

Calcific tendinitis of the rotator cuff

Calcific tendinitis within the rotator cuff tendon is a common shoulder disorder that should be differentiated from dystrophic calcification as the pathogenesis and natural history of both is totally different. Calcific tendinitis usually occurs in the fifth and sixth decades of life among sedentary workers. It is classified into formative and resorptive phases. The chronic formative phase results from transient hypoxia that is commonlyassociated with repeated microtrauma causing calcium deposition into the matrix vesicles within the chondrocytes forming bone foci that later coalesce. This phase may extend from 1 to 6 years, and is usually asymptomatic. The resorptive phase extends from 3 wk up to 6 mo with vascularization at the periphery of the calcium deposits causing macrophage and mononuclear giant cell infiltration, together with fibroblast formation leading to an aggressive inflammatory reaction with inflammatory cell accumulation, excessive edema and rise of the intra-tendineous pressure. This results in a severely painful shoulder. Radiological investigations confirm the diagnosis and suggest the phase of the condition and are used to follow its progression. Although routine conventional X-ray allows detection of the deposits, magnetic resonance imaging studies allow better evaluation of any coexisting pathology. Various methods of treatment have been suggested. The appropriate method should be individualized for each patient. Conservative treatment includes pain killers and physiotherapy, or "minimally invasive" techniques as needling or puncture and aspiration. It is almost always successful since the natural history of the condition ends with resorption of the deposits and complete relief of pain. Due to the intolerable pain of the acute and severely painful resorptive stage, the patient often demands any sort of operative intervention. In such case arthroscopic removal is the best option as complete removal of the deposits is unnecessary.

Functional outcomes of traumatic and non-traumatic rotator cuff tears after arthroscopic repair

AIM To compare the functional outcomes of traumatic and non-traumatic rotator cuff tears after arthroscopic repair. METHODS Eighty-seven patients with rotator cuff tears following arthroscopic treatment were divided into traumatic and non-traumatic tear groups. Postoperative muscle strength and outcomes using the modified University of California, Los Angeles score were evaluated. Sex, age, affected limb and dominant limb were correlated between groups. Muscle strength of the repaired and unaffected shoulders was compared. Rotator cuff injury size was measured. RESULTS Of the 87 patients who underwent rotator cuff repairs, 35 had traumatic tears and 52 had non-traumatic tears. In patients with non-traumatic tears, the average age was 59 years, 74.5% were female, 96.1% were righthand dominant and 92.3% had their dominant shoulder affected. Patients with traumatic tears were 59.5 yearsold on average, 51.4% were female, 91.4% were righthand dominant and 88.5% had their dominant shoulder affected. No difference existed in the mean modified University of California, Los Angeles score between patients with traumatic tears(33.7) compared with those with non-traumatic tears(32.8). No strength differences were observed between groups: The strength difference between the non-affected and affected sides was 1.21 kg in the non-traumatic group and 1.39 kg in the traumatic group(P = 0.576), while the strength ratio between the non-affected/affected sides was 0.805 in the nontraumatic group and 0.729 in the traumatic group(P = 0.224). CONCLUSION The functional results of traumatic rotator cuff repairs are similar to non-traumatic tears. Both outcomes are satisfactory.

Rotator cuff tears: An evidence based approach

Lesions of the rotator cuff(RC) are a common occurrence affecting millions of people across all parts of the globe. RC tears are also rampantly prevalent with an agedependent increase in numbers. Other associated factors include a history of trauma, limb dominance, contralateral shoulder, smoking-status, hypercholesterolemia, posture and occupational dispositions. The challenge lies in early diagnosis since a high proportion of patients are asymptomatic. Pain and decreasing shoulder power and function should alert the heedful practitioner in recognizing promptly the onset or aggravation of existing RC tears. Partial-thickness tears(PTT) can be bursalsided or articular-sided tears. Over the course of time, PTT enlarge and propagate into full-thickness tears(FTT) and develop distinct chronic pathological changes due to muscle retraction, fatty infiltration and muscle atrophy. These lead to a reduction in tendon elasticity and viability. Eventually, the glenohumeral joint experiences a series of degenerative alterations- cuff tear arthropathy. To avert this, a vigilant clinician must utilize and corroborate clinical skill and radiological findings to identify tear progression. Modern radio-diagnostic means of ultrasonography and magnetic resonance imaging provide excellent visualization of structural details and are crucial in determining further course of action for these patients. Physical therapy along with activity modifications, antiinflammatory and analgesic medications form the pillars of nonoperative treatment. Elderly patients with minimal functional demands can be managed conservatively and reassessed at frequent intervals. Regular monitoring helps in isolating patients who require surgical interventions. Early surgery should be considered in younger, active and symptomatic, healthy patients. In addition to being costeffective, this helps in providing a functional shoulder witha stable cuff. An easily reproducible technique of maximal strength and sturdiness should by chosen among the armamentarium of the shoulder surgeon. Grade 1 PTTs do well with debridement while more severe lesions mandate repair either by trans-tendon technique or repair following conversion into FTT. Early repair of repairable FTT can avoid appearance and progression of disability and weakness. The choice of surgery varies from surgeon-to-surgeon with arthroscopy taking the lead in the current scenario. The double-row repairs have an edge over the single-row technique in some patients especially those with massive tears. Stronger, costeffective and improved functional scores can be obtained by the former. Both early and delayed postoperative rehabilitation programmes have led to comparable outcomes. Guarded results may be anticipated in patients in extremes of age, presence of comorbidities and severe tear patters. Overall, satisfactory results are obtained with timely diagnosis and execution of the appropriate treatment modality.

Stem cell therapy in the management of shoulder rotator cuff disorders

Rotator cuff tears are frequent shoulder problems that are usually dealt with surgical repair. Despite improved surgical techniques, the tendon-to-bone healing rate is unsatisfactory due to difficulties in restoring the delicate transitional tissue between bone and tendon. It is essential to understand the molecular mechanisms that determine this failure. The study of the molecular environment during embryogenesis and during normal healing after injury is key in devising strategies to get a successful repair. Mesenchymal stem cells(MSC) can differentiate into different mesodermal tissues and have a strong paracrine, anti-inflammatory, immunoregulatory and angiogenic potential. Stem cell therapy is thus a potentially effective therapy to enhance rotator cuff healing. Promising results have been reported with the use of autologous MSC of different origins in animal studies: they have shown to have better healing properties, increasing the amount of fibrocartilage formation and improving the orientation of fibrocartilage fibers with less immunologic response and reduced lymphocyte infiltration. All these changes lead to an increase in biomechanical strength. However, animal research is still inconclusive and more experimental studies are needed before human application. Future directions include expanded stem cell therapy in combination with growth factors or different scaffolds as well as new stem cell types and gene therapy.

Arthroscopic treatment options for irreparable rotator cuff tears of the shoulder

The management of patients with irreparable rotator cuff tears remains a challenge for orthopaedic surgeons with the final treatment option in many algorithms being either a reverse shoulder arthroplasty or a tendon transfer. The long term results of these procedures are however still widely debated, especially in younger patients. A variety of arthroscopic treatment options have been proposed for patients with an irreparable rotator cuff tear without the presence of arthritis of the glenohumeral joint. These include a simple debridement with or without a biceps tenotomy, partial rotator cuff repair with or without an interval slide, tuberplasty, graft interposition of the rotator cuff, suprascapular nerve ablation, superior capsule reconstruction and insertion of a biodegradable spacer(Inspace) to depress the humeral head. These options should be considered as part of the treatment algorithm in patients with an irreparable rotator cuff and could be used as either as an interim procedure, delaying the need for more invasive surgery in the physiologically young and active, or as potential definitive procedures in the medically unfit.The aim of this review is to highlight and summarise arthroscopic procedures and the results thereof currently utilised in the management of these challenging patients.

Reporting rotator cuff tears on magnetic resonance arthrography using the Snyder's arthroscopic classification

AIM To determine diagnostic performance of magnetic resonance arthrography(MRA) in evaluating rotator cuff tears(RCTs) using Snyder's classification for reporting.METHODS One hundred and twenty-six patients(64 males, 62 females; median age 55 years) underwent shoulder MRA and arthroscopy, which represented our reference standard. Surgical arthroscopic reports were reviewed and the reported Snyder's classification was recorded. MRA examinations were evaluated by two independent radiologists(14 and 5 years' experience) using Snyder's classification system, blinded to arthroscopy. Agreement between arthroscopy and MRA on partial-and fullthickness tears was calculated, first regardless of their extent. Then, analysis took into account also the extent of the tear. Interobserver agreement was also calculated the quadratically-weighted Cohen kappa statistics.RESULTS On arthroscopy, 71/126 patients(56%) had a fullthickness RCT. The remaining 55/126 patients(44%) had a partial-thickness RCT. Regardless of tear extent, out of 71 patients with arthroscopically-confirmed fullthickness RCTs, 66(93%) were correctly scored by both readers. All 55 patients with arthroscopic diagnosis of partial-thickness RCT were correctly assigned as having a partial-thickness RCT at MRA by both readers. Interobserver reproducibility analysis showed total agreement between the two readers in distinguishing partial-thickness from full-thickness RCTs, regardless of tear extent(k = 1.000). With regard to tear extent, in patients in whom a complete tear was correctly diagnosed, correct tear extent was detected in 61/66 cases(92%); in the remaining 5/66 cases(8%), tear extent was underestimated. Agreement was k = 0.955. Interobserver agreement was total(k = 1.000).CONCLUSION MRA shows high diagnostic accuracy and reproducibility in evaluating RCTs using the Snyder's classification for reporting. Snyder's classification may be adopted for routine reporting of MRA.

Postoperative deep shoulder infections following rotator cuff repair

Rotator cuff repair(RCR) is one of the most commonly performed surgical procedures in orthopaedic surgery. The reported incidence of deep soft-tissue infections after RCR ranges between 0.3% and 1.9%. Deep shoulder infection after RCR appears uncommon, but the actual incidence may be higher as many cases may go unreported. Clinical presentation may include increasing shoulder pain and stiffness, high temperature, local erythema, swelling, warmth, and fibrinous exudate. Generalized fatigue and signs of sepsis may be present in severe cases. Varying clinical presentation coupled with a low index of suspicion may result in delayed diagnosis. Laboratory findings include high erythrocyte sedimentation rate and C-reactive protein level, and, rarely, abnormal peripheral blood leucocyte count. Aspiration of glenohumeral joint synovial fluid with analysis of cell count, gram staining and culture should be performed in all patients suspected with deep shoulder infection after RCR. The most commonly isolated pathogens are Propionibacterium acnes, Staphylococcus epidermidis, and Staphylococcus aureus. Management of a deep soft-tissue infection of the shoulder after RCR involves surgical debridement with lavage and long-term intravenous antibiotic treatment based on the pathogen identified. Although deep shoulder infection after RCR is usually successfully treated, complications of this condition can be devastating. Prolonged course of intravenous antibiotic treatment, extensive soft-tissue destruction and adhesions may result in substantially diminished functional outcomes.