The use of the long head of triceps interposition muscle flap for treatment of massive rotator cuff tears

Massive rotator cuff tears present a difficult problem for orthopedic surgeons. To address this problem, a long head of triceps muscle interposition flap was proposed. Ten patients underwent repair of massive rotator cuff tears using the triceps muscle flap. The patients' strength and range of motion were tested preoperatively, and a University of California, Los Angeles, shoulder score was assigned. Similar testing was performed 1 year later. Postoperatively, the patients showed significant improvement in the overall shoulder score and in the pain and function components of the score. There was no significant improvement in shoulder range of motion, except for shoulder flexion. An important finding was that there was no loss of strength in elbow extension following the loss of the long head of triceps muscle. It was concluded that the long head of triceps interposition flap is useful in the reconstruction of the massive rotator cuff tear.     

肩袖间隙影像解剖及常见病变的研究进展

肩袖间隙在解剖学上是肩关节的一个复合区域,在维持肩关节稳定性和保护肱二头肌长头肌腱功能起重要作用。对肩袖间隙解剖结构及功能的深入认识有助于肩袖间隙损伤性病变、挛缩性病变等的及时诊断和合理治疗。影像学检查尤其是磁共振逐步成为肩袖间隙疾病最主要的检查方法,包括常规扫描、直接及间接性磁共振肩关节造影、增强扫描等。本文将就肩袖间隙的影像解剖及常见病变的相关研究进行综述。     

Albendazole chemotherapy for treatment of diarrhoea in patients with AIDS in Zambia: a randomised double blind controlled trial.

OBJECTIVE--To determine the value of short course, high dose albendazole chemotherapy in the treatment of persistent diarrhoea related to HIV in unselected patients in urban Zambia. DESIGN--A randomised double blind placebo controlled trial of albendazole 800 mg twice daily for two weeks. Patients were monitored intensively for one month and followed for up to six months. SETTING--Home care. AIDS services in Lusaka and Ndola. PATIENTS--174 HIV seropositive patients with persistent diarrhoea (defined as loose but not bloody stools three or more times a day for three weeks or longer). No investigations were undertaken except HIV testing after counselling. MAIN OUTCOME MEASURES--Proportion of time periods during which diarrhoea was experienced after completion of treatment; proportion of patients with full remission after completion of treatment; mortality. RESULTS--The patients taking albendazole had diarrhoea on 29% fewer days than those taking placebo (P < 0.0001) in the two weeks after treatment. The benefit of albendazole was maintained over six months. In patients with a Karnofsky score of 50 to 70 (needing help with activities of daily living and unable to work, but not needing admission to hospital) diarrhoea was reduced by 50%. Remission was obtained in 26% of all patients who received albendazole (P = 0.004 against 9% receiving placebo), and this difference was maintained over six months (log rank test, P = 0.003). Albendazole had no effect on mortality. Minimal adverse effects were noted. CONCLUSIONS--For HIV infected Zambians with diarrhoea of more than three weeks'' duration albendazole offers substantial relief from symptoms and may be used empirically, without prior investigation.     

Short course chemotherapy for tuberculous lymphadenitis in children.

OBJECTIVE--To assess the efficacy of a short course chemotherapy regimen for treating tuberculosis of the lymph nodes in children. DESIGN--Open, collaborative, outpatient clinical trial. SETTING--Outpatient department of the Tuberculosis Research Centre, paediatric surgery departments of the Institute of Child Health and Hospital for Children and the Government Stanley Hospital, Madras, South India. PATIENTS--Children aged 1-12 years with extensive, multiple site, superficial tuberculous lymphadenitis confirmed by biopsy (histopathology or culture). INTERVENTIONS--Patients were treated with a fully supervised intermittent chemotherapy regimen consisting of streptomycin, rifampicin, isoniazid, and pyrazinamide three times a week for two months followed by streptomycin and isoniazid twice a week for four months on an outpatient basis. Surgery was limited to biopsy of nodes for diagnosis and assessment. MAIN OUTCOME MEASURES--Response to chemotherapy was assessed by regression of lymph nodes and healing of sinuses and abscesses during treatment and follow up. Compliance with treatment and frequency of adverse reactions were also estimated. RESULTS--197 Patients were admitted to the study and 168 into the analysis. The regimen was well tolerated and compliance was good with 101 (60%) patients receiving the prescribed chemotherapy within 15 days of the stipulated period of six months. Those whose chemotherapy extended beyond that period received the same total number of doses. Clinical response was favourable in most patients at the end of treatment. Sinuses and abscesses healed rapidly. Residual lymphadenopathy (exceeding 10 mm diameter) was present in 50 (30%) patients at the end of treatment; these nodes were biopsied. Fresh nodes, increase in size of nodes, and sinuses and abscesses occurred both during treatment and follow up. After 36 months of follow up after treatment only 5 (3%) patients required retreatment for tuberculosis. CONCLUSION--Tuberculous lymphadenitis in children can be successfully treated with a short course chemotherapy regimen of six months.     

Effectiveness of massage therapy for subacute low-back pain: a randomized controlled trial

BACKGROUND: The effectiveness of massage therapy for low-back pain has not been documented. This randomized controlled trial compared comprehensive massage therapy (soft-tissue manipulation, remedial exercise and posture education), 2 components of massage therapy and placebo in the treatment of subacute (between 1 week and 8 months) low-back pain. METHODS: Subjects with subacute low-back pain were randomly assigned to 1 of 4 groups: comprehensive massage therapy (n = 25), soft-tissue manipulation only (n = 25), remedial exercise with posture education only (n = 22) or a placebo of sham laser therapy (n = 26). Each subject received 6 treatments within approximately 1 month. Outcome measures obtained at baseline, after treatment and at 1-month follow-up consisted of the Roland Disability Questionnaire (RDQ), the McGill Pain Questionnaire (PPI and PRI), the State Anxiety Index and the Modified Schober test (lumbar range of motion). RESULTS: Of the 107 subjects who passed screening, 98 (92%) completed post-treatment tests and 91 (85%) completed follow-up tests. Statistically significant differences were noted after treatment and at follow-up. The comprehensive massage therapy group had improved function (mean RDQ score 1.54 v. 2.86-6.5, p < 0.001), less intense pain (mean PPI score 0.42 v. 1.18-1.75, p < 0.001) and a decrease in the quality of pain (mean PRI score 2.29 v. 4.55-7.71, p = 0.006) compared with the other 3 groups. Clinical significance was evident for the comprehensive massage therapy group and the soft-tissue manipulation group on the measure of function. At 1-month follow-up 63% of subjects in the comprehensive massage therapy group reported no pain as compared with 27% of the soft-tissue manipulation group, 14% of the remedial exercise group and 0% of the sham laser therapy group. INTERPRETATION: Patients with subacute low-back pain were shown to benefit from massage therapy, as regulated by the College of Massage Therapists of Ontario and delivered by experienced massage therapists.     

桡骨远端骨折治疗的选择

目的：探讨不同类型的桡骨远端骨折的有效治疗方法。方法：分析106例桡骨远端骨折,分别采用闭合手法复位,切开复位或有限切开复位内固定方法,分别对骨折复位比较及功能评分。结果：完整随访106例桡骨远端骨折病例,随访时间3～21个月。对保守治疗组与手术治疗组进行骨折复位测定及改良Garland和Werley评分,A,B型骨折无显著性差异;C型骨折中,手术组明显优于保守治疗组。结论：对于C型骨折,建议行切开复位内固定治疗;对于A,B型需根据实际情况选择治疗方式。     

Randomised controlled trial of graded exercise in patients with the chronic fatigue syndrome.

OBJECTIVE: To test the efficacy of a graded aerobic exercise programme in the chronic fatigue syndrome. DESIGN: Randomised controlled trial with control treatment crossover after the first follow up examination. SETTING: Chronic fatigue clinic in a general hospital department of psychiatry. SUBJECTS: 66 patients with the chronic fatigue syndrome who had neither a psychiatric disorder nor appreciable sleep disturbance. INTERVENTIONS: Random allocation to 12 weeks of either graded aerobic exercise or flexibility exercises and relaxation therapy. Patients who completed the flexibility programme were invited to cross over to the exercise programme afterwards. MAIN OUTCOME MEASURE: The self rated clinical global impression change score, "very much better" or "much better" being considered as clinically important. RESULTS: Four patients receiving exercise and three receiving flexibility treatment dropped out before completion. 15 of 29 patients rated themselves as better after completing exercise treatment compared with eight of 30 patients who completed flexibility treatment. Analysis by intention to treat gave similar results (17/33 v 9/33 patients better). Fatigue, functional capacity, and fitness were significantly better after exercise than after flexibility treatment. 12 of 22 patients who crossed over to exercise after flexibility treatment rated themselves as better after completing exercise treatment 32 of 47 patients rated themselves as better three months after completing supervised exercise treatment 35 of 47 patients rated themselves as better one year after completing supervised exercise treatment. CONCLUSION: These findings support the use of appropriately prescribed graded aerobic exercise in the management of patients with the chronic fatigue syndrome.     

Effect of biceps-to-triceps transfer on rotator cuff stress during upper limb weight-bearing lift in tetraplegia: A modeling and simulation analysis

Rotator cuff stress during upper limb weight-bearing lifts presumably contribute to rotator cuff disease, which is the most common cause of shoulder pain in individuals with tetraplegia. Elbow extension strength appears to be a key determinant of rotator cuff stress during upper limb weight-bearing lifts since individuals with paraplegia who generate greater elbow extensor moments experience lower rotator cuff stress relative to individuals with tetraplegia. Biceps-to-triceps transfer surgery can increase elbow extension strength in individuals with tetraplegia. The purpose of this study was to determine whether active elbow extension via biceps transfer decreases rotator cuff stress during weight-bearing lifts in individuals with tetraplegia. A forward dynamics computational framework was used to estimate muscle stress during the lift; stress was computed as muscle force divided by the peak isometric muscle force. We hypothesized that rotator cuff stresses would be lower in simulated lifting with biceps transfer relative to simulated lifting without biceps transfer. We found that limited elbow extension strength in individuals with tetraplegia, regardless of whether elbow strength is enabled via biceps transfer or is residual after spinal cord injury, results in muscle stresses exceeding 85% of the peak isometric muscle stress in the supraspinatus, infraspinatus, and teres minor. The rotator cuff stresses we estimated suggest that performance of weight-bearing activities should be minimized or assisted in order to reduce the risk for shoulder pain. Our results also indicate that biceps transfer is unlikely to decrease rotator cuff stress during weight-bearing lifts in individuals with tetraplegia.     

Rotator cuff tears: what have we learned from animal models?

Rotator cuff tendon tears are among the most common soft tissue injuries that occur at the shoulder. Despite advancements in surgical repair techniques, rotator cuff repairs experience a high rate of failure. The common occurrence of tears and the frequency of re-tears require a further understanding of the mechanisms associated with injuries, healing, and regeneration of the rotator cuff. This paper reviews in vivo studies using the various animal shoulder models of the rat, rabbit, sheep, canine, and primate. These animal models have been used to study intrinsic and extrinsic factors leading to shoulder degeneration, various suture techniques, effects of post-surgical treatment, numerous biologic and synthetic scaffolds, and an assortment of biologic augmentations used to accelerate healing. These effects can be examined in a controlled manner using animal models without other confounding factors that sometimes limit clinical studies. The clinically impactful results will be explained to highlight the specific knowledge gained from using animal models in rotator cuff research.     

Differences in glutamate receptors and inflammatory cell numbers are associated with the resolution of pain in human rotator cuff tendinopathy

IntroductionThe relationship between peripheral tissue characteristics and pain symptoms in soft tissue inflammation is poorly understood. The primary aim of this study was to determine immunohistochemical differences in tissue obtained from patients with persistent pain and patients who had become pain-free after surgical treatment for rotator cuff tendinopathy. The secondary aim was to investigate whether there would be differences in glutaminergic and inflammatory gene expression between disease-derived and healthy control cells in vitro.MethodsSupraspinatus tendon biopsies were obtained from nine patients with tendon pain before shoulder surgery and from nine further patients whose pain had resolved completely following shoulder surgery. Histological markers relating to the basic tendon characteristics, inflammation and glutaminergic signalling were quantified by immunohistochemical analysis. Gene expression of glutaminergic and inflammatory markers was determined in tenocyte explants derived from painful rotator cuff tendon tears in a separate cohort of patients and compared to that of explants from healthy control tendons. Dual labelling was performed to identify cell types expressing nociceptive neuromodulators.ResultsTendon samples from patients with persistent pain demonstrated increased levels of metabotropic glutamate receptor 2 (mGluR2), kainate receptor 1 (KA1), protein gene product 9.5 (PGP9.5), CD206 (macrophage marker) and CD45 (pan-leucocyte marker) versus pain-free controls (p <0.05). NMDAR1 co-localised with CD206-positive cells, whereas PGP9.5 and glutamate were predominantly expressed by resident tendon cells. These results were validated by in vitro increases in the expression of mGluR2, N-methyl-D-aspartate receptor (NMDAR1), KA1, CD45, CD206 and tumour necrosis factor alpha (TNF-α) genes (p <0.05) in disease-derived versus control cells.ConclusionsWe conclude that differences in glutamate receptors and inflammatory cell numbers are associated with the resolution of shoulder pain in rotator cuff tendinopathy, and that disease-derived cells exhibit a distinctly different neuro-inflammatory gene expression profile to healthy control cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0691-5) contains supplementary material, which is available to authorized users.     

Using support vector machines to optimally classify rotator cuff strength data and quantify post-operative strength in rotator cuff tear patients

Shoulder strength data are important for post-operative assessment of shoulder function and have been used in diagnosis of rotator cuff pathology. Support vector machines (SVM) employ complex analysis techniques to solve classification and regression problems. A SVM, a machine learning technique, can be used for analysis and classification of shoulder strength data. The goals of this study were to determine the diagnostic competency of SVM based on shoulder strength data and to apply SVM analysis in efforts to derive a single representative shoulder strength score. Data were taken from fourteen isometric shoulder strength measurements of each shoulder (involved and uninvolved) in 45 rotator cuff tear patients. SVM diagnostic proficiency was found to be comparable to reported ultrasound values. Improvement of shoulder function was accurately represented by a single score in pairwise comparison of the pre-operative and the 12 month post-operative group (P < 0.004). Thus, the SVM-based score may be a promising metric for summarizing rotator cuff strength data.     

Brachial Artery Flow-mediated Dilation Following Exercise with Augmented Oscillatory and Retrograde Shear Rate

ABSTRACT: BACKGROUND: Acute doses of elevated retrograde shear rate (SR) appear to be detrimental to endothelial function in resting humans. However, retrograde shear increases during moderate intensity exercise which also enhances post-exercise endothelial function. Since SR patterns differ with the modality of exercise, it is important to determine if augmented retrograde SR during exercise influences post-exercise endothelial function. This study tested the hypothesis that (1) increased doses of retrograde SR in the brachial artery during lower body supine cycle ergometer exercise would attenuate post-exercise flow-mediated dilation (FMD) in a dose-dependent manner, and (2) antioxidant vitamin C supplementation would prevent the attenuated post-exercise FMD response. METHODS: Twelve men participated in four randomized exercise sessions (90 W for 20 minutes) on separate days. During three of the sessions, one arm was subjected to increased oscillatory and retrograde SR using three different forearm cuff pressures (20, 40, 60 mmHg) (contralateral arm served as the control) and subjects ingested placebo capsules prior to exercise. A fourth session with 60 mmHg cuff pressure was performed with 1 g of vitamin C ingested prior to the session. RESULTS: Post-exercise FMD following the placebo conditions were lower in the cuffed arm versus the control arm (arm main effect: P < 0.05) and without differences between cuff pressures (20 mmHg: 5.7 [PLUS-MINUS SIGN] 2.2 %; 40 mmHg: 4.7 [PLUS-MINUS SIGN] 1.3 %; 60 mmHg: 5.4 [PLUS-MINUS SIGN] 2.4 %) (P > 0.05). Following vitamin C treatment, post-exercise FMD in the cuffed and control arm increased from baseline (P < 0.05) but were not different (control: 7.1 [PLUS-MINUS SIGN] 3.5 % vs. cuffed: 6.6 [PLUS-MINUS SIGN] 3.3 %) (P > 0.05). CONCLUSIONS: These results indicate that augmented oscillatory and retrograde SR in non-working limbs during lower body exercise attenuates post-exercise FMD without an evident dose--response in the range of cuff pressures evaluated. Vitamin C supplementation prevented the attenuation of FMD following exercise with augmented oscillatory and retrograde SR suggesting that oxidative stress contributes to the adverse effects of oscillatory and retrograde shear during exercise on FMD.     

Development of an Arthroscopic Joint Capsule Injury Model in the Canine Shoulder

Background

The natural history of rotator cuff tears can be unfavorable as patients develop fatty infiltration and muscle atrophy that is often associated with a loss of muscle strength and shoulder function. To facilitate study of possible biologic mechanisms involved in early degenerative changes to rotator cuff muscle and tendon tissues, the objective of this study was to develop a joint capsule injury model in the canine shoulder using arthroscopy.

Methods

Arthroscopic surgical methods for performing a posterior joint capsulectomy in the canine shoulder were first defined in cadavers. Subsequently, one canine subject underwent bilateral shoulder joint capsulectomy using arthroscopy, arthroscopic surveillance at 2, 4 and 8 weeks, and gross and histologic examination of the joint at 10 weeks.

Results

The canine subject was weight-bearing within eight hours after index and follow-up surgeries and had no significant soft tissue swelling of the shoulder girdle or gross lameness. Chronic synovitis and macroscopic and microscopic evidence of pathologic changes to the rotator cuff bony insertions, tendons, myotendinous junctions and muscles were observed.

Conclusions

This study demonstrates feasibility and proof-of-concept for a joint capsule injury model in the canine shoulder. Future work is needed to define the observed pathologic changes and their role in the progression of rotator cuff disease. Ultimately, better understanding of the biologic mechanisms of early progression of rotator cuff disease may lead to clinical interventions to halt or slow this process and avoid the more advanced and often irreversible conditions of large tendon tears with muscle fatty atrophy.     

Effect on intra-arterial blood pressure of slow release metoprolol combined with placebo or chlorthalidone.

Thirty patients with essential hypertension participated in a double blind crossover trial in which they were randomly allocated to treatment with either once daily slow release metoprolol (200 mg) with placebo or once daily slow release metoprolol (200 mg) with chlorthalidone (25 mg). Ambulatory intra-arterial blood pressure was recorded continuously for 24-48 hours before treatment and two months after each change in regimen. The response of blood pressure and pulse rate to a standard exercise protocol that included supine rest and tilt, isometric, and dynamic bicycle exercise was measured during the same recording periods. Both treatments appreciably reduced blood pressure and pulse rate; mean daytime intra-arterial blood pressure was reduced from 174/95 mm Hg to 158/85 mm Hg by metoprolol plus placebo and to 143/78 mm Hg by metoprolol plus chlorthalidone. This reduction with the combined treatment was significantly greater than with metoprolol and placebo (p systolic = 0.001, p diastolic = 0.004). Mean night time pressures were reduced from 148/78 mm Hg to 139/75 mm Hg by metoprolol plus placebo and to 116/61 mm Hg by metoprolol plus chlorthalidone. Again the reduction in blood pressure was significantly greater with combined treatment (p less than 0.001) than with metoprolol plus placebo. Once daily slow release metoprolol is effective in controlling blood pressure, but this effect is greatly enhanced by the addition of a diuretic.     

Measuring dynamic in-vivo glenohumeral joint kinematics: technique and preliminary results

Rotator cuff tears are a common injury that affect a significant percentage of the population over age 60. Although it is widely believed that the rotator cuff's primary function is to stabilize the humerus against the glenoid during shoulder motion, accurately measuring the three-dimensional (3D) motion of the shoulder's glenohumeral joint under in-vivo conditions has been a challenging endeavor. In particular, conventional motion measurement techniques have frequently been limited to static or two-dimensional (2D) analyses, and have suffered from limited or unknown in-vivo accuracy. We have recently developed and validated a new model-based tracking technique that is capable of accurately measuring the 3D position and orientation of the scapula and humerus from biplane X-ray images. Herein we demonstrate the in-vivo application of this technique for accurately measuring glenohumeral joint translations during shoulder motion in the repaired and contralateral shoulders of patients following rotator cuff repair. Five male subjects were tested at 3-4 months following arthroscopic rotator cuff repair. Superior-inferior humeral translation was measured during elevation, and anterior-posterior humeral translation was measured during external rotation in both the repaired and contralateral shoulders. The data failed to detect statistically significant differences between the repaired and contralateral shoulders in superior-inferior translation (p=0.74) or anterior-posterior translation (p=0.77). The measurement technique overcomes the limitations of conventional motion measurement techniques by providing accurate, 3D, in-vivo measures of glenohumeral joint motion during dynamic activities. On-going research is using this technique to assess the effects of conservative and surgical treatment of rotator cuff tears.     

Effect of rotator cuff exercise on humeral rotation torque in healthy individuals

Conservative management of rotator cuff pathology often involves certain therapeutic exercises. Although a major goal of these exercises is to increase strength of the rotator cuff, little empirical evidence supports this assertion. In this study, 34 nonpathologic young adults were pretested using a LIDO Multijoint II isokinetic device for average and peak torque generated during internal and external rotation. Subjects were arbitrarily assigned to a right-arm- or left-arm-trained group, exercised for 4 weeks, and then posttested for changes in humeral rotation torque. Moderate but significant increases in torque (8-10%) as well as in total work done were observed in both groups, only in the trained arm. Subjects who trained the nondominant (left) arm experienced gains similar to those who trained the right arm. Gains were significant in the case of both internal and external rotation (also average as well as peak torque), with men and women experiencing the same relative increases. These data, in addition to supporting the use of selected exercises to increase humeral rotation torque in a healthy population, offer a potential model for the rehabilitation of patients with rotator cuff injury.     

点压按摩第二掌骨全息穴点联合冲击波治疗慢性肩袖损伤的临床研究

摘要 目的：探究点压按摩第二掌骨全息穴点联合冲击波治疗慢性肩袖损伤患者的临床疗效。方法：选取2019年1月-2019年12月本院接诊的122例慢性肩袖损伤患者展开研究,使用随机数字表法将两组患者随机分为研究组和常规组,每组患者均61例。给予常规组患者体外冲击波治疗,在常规组治疗的基础上给予研究组患者第二掌骨全息穴点点压按摩治疗。观察两组患者的临床疗效、美国加州大学肩关节评分量表(UCLA)评分、视觉疼痛模拟评分（VAS）、肩关节活动度(ROM)以及并发症的发生率。结果：研究组患者的总有效率显著高于常规组（P＜0.05）;治疗后,两组患者的UCLA评分均得到显著改善,且研究组患者改善优于常规组（P＜0.05）;两组患者的VAS评分显著降低,且研究组患者VAS评分显著低于常规组（P＜0.05）;两组患者的前屈、外展、体侧外旋ROM均优于治疗前,研究组患者ROM显著优于常规组（P＜0.05）。治疗后随访1年,研究组患者并发症发生率显著低于常规组（P＜0.05）。结论：第二掌骨全息穴点点压按摩结合冲击波治疗慢性肩袖损伤患者,可以提升患者的临床疗效,改善患者的肩关节功能,减轻疼痛,降低患者的并发症,具有较高的临床意义,值得在临床推广使用。     

Purine metabolism and clinical status of patients with rheumatoid arthritis treated with dipyridamole

The anti-inflammatory activities of methotrexate and sulphasalazine may be mediated by increases in endogenous adenosine levels. Since the vascular protective drug dipyridamole inhibits the uptake and metabolism of adenosine we have now tested this compound in patients with rheumatoid arthritis to assess its effects on their symptoms. Forty patients (aged 18-75 years) received dipyridamole 400 mg/day or placebo. The levels of adenosine and its major metabolites were determined by high performance liquid chromatography (HPLC) in blood samples taken at baseline and at monthly intervals during treatment for 6 months. After three months of treatment there was a significant reduction in the modified Health Assessment Questionnaire (mHAQ) score, but these effects were not maintained, and dipyridamole did not modify disease severity scores or the levels of adenosine and its metabolites. We conclude that the symptoms of rheumatoid arthritis were not modified by treatment with dipyridamole.     

How patients use domiciliary oxygen.

Forty-five patients in Southampton who received domiciliary oxygen were visited at home to find out how they used and coped with their oxygen. Generally, the organisation and administration of supplies presented no problems, nearly all the apparatus complied with the drug tariff, and most patients coped well with the equipment. Only two patients were taking oxygen for prescribed periods; the others were taking it when necessary for symptomatic relief. No patient received oxygen for over five hours daily. Most patients thought that they were helped by oxygen, but only four said that it allowed them to increase their level of activity, and the overall benefit seemed slight. This was partly because oxygen was usually limited to one room, so patients used oxygen after rather than during exercise. The amount of oxygen consumed differed widely, ranging from three and a half cylinders a week in three patients to less than one cylinder in six months in 17 patients. The average yearly cost of oxygen per patient ranged from 500 pounds in patients consuming one cylinder or more per week, to 15 pounds in those consuming less than one cylinder in six months. The main cost of domiciliary oxygen is determined by the number of cylinder refills, so patients who use it infrequently are a relatively small drain on resources.     

Predicting Rotator Cuff Tears Using Data Mining and Bayesian Likelihood Ratios

Objectives

Rotator cuff tear is a common cause of shoulder diseases. Correct diagnosis of rotator cuff tears can save patients from further invasive, costly and painful tests. This study used predictive data mining and Bayesian theory to improve the accuracy of diagnosing rotator cuff tears by clinical examination alone.

Methods

In this retrospective study, 169 patients who had a preliminary diagnosis of rotator cuff tear on the basis of clinical evaluation followed by confirmatory MRI between 2007 and 2011 were identified. MRI was used as a reference standard to classify rotator cuff tears. The predictor variable was the clinical assessment results, which consisted of 16 attributes. This study employed 2 data mining methods (ANN and the decision tree) and a statistical method (logistic regression) to classify the rotator cuff diagnosis into “tear” and “no tear” groups. Likelihood ratio and Bayesian theory were applied to estimate the probability of rotator cuff tears based on the results of the prediction models.

Results

Our proposed data mining procedures outperformed the classic statistical method. The correction rate, sensitivity, specificity and area under the ROC curve of predicting a rotator cuff tear were statistical better in the ANN and decision tree models compared to logistic regression. Based on likelihood ratios derived from our prediction models, Fagan''s nomogram could be constructed to assess the probability of a patient who has a rotator cuff tear using a pretest probability and a prediction result (tear or no tear).

Conclusions

Our predictive data mining models, combined with likelihood ratios and Bayesian theory, appear to be good tools to classify rotator cuff tears as well as determine the probability of the presence of the disease to enhance diagnostic decision making for rotator cuff tears.