Sunday, April 19, 2009

Truth in Diagnosis. A simple guide to important statistics.

Truth in Diagnosis: An evidence based perspective

Essentials made simple.


It is becoming increasingly important for therapists to understand the tests they are using on a daily basis. Terms like sensitivity , specificity and likelyhood ratio are essential terms to understand. Below is, hopefully, a simple guide ot their use and importance.

1. 2x2 contingency tables



1. Sensitivity and Specificity

Sensitivity= True positive rate ( A/ A+C )

Specificity= True false rate ( D/ B+D )


2. SnOUT and SpIN

When sensitivity is high you can use the test to rule things out. When specificity is high you can use the test to rule things in.

Another way of remembering is Sn N OUT (Sensitivity high and test Negative rule OUT), Sp P IN (Specificty high and test Positive Rule IN)


3. Positive and negative predictive values (PPV & NPV )

The positive predictive value is the proportion of subjects with a positive test result who actually have the condition.
( A/ A+B )

The negative predictive value is the proportion of subjects with a negative result who do not have the condition. ( D/ C+D)


“Despite their apparent usefulness, predictive values can be deceptive because they are highly dependent on the prevalence of a condition of interest in the sample. “ ( Fritz 2001)


4. Likelihood ratio

+ Likelihood ratio= Sensitivity / 1- specificity

- Likelihood ratio= (1-sensitivity)/ specificity

Likelihood ration is independent of the prevalence in a population.


+LHR
1-2: minimal changes in odds

2-5: small shifts in probability
5-10: moderate shifts in probability
10+: large shifts in probability



-LHR

0.5-1: minimal changes in probability
0.2-0.5: small shifts in probability
0.1-0.2: moderate shifts in probability

<0.1: color="#000000">5. Pre and post test odds.

Pre test odds is the prevalence in your practice.

Post test odds= Pretest odds x likelihood ration

Or we can use a “Nomogram” to determine the effect of a test on the pretest odds, if we know the likelihood ratio of our test.


Nomogram for calculating post test odds.


Practical example

Clinical Diagnosis of an Anterior Cruciate Ligament Rupture: A Meta-analysis.Anne Benjaminse, PT1 ,Gokeler, PT2 Cees P. van der Schans, PT, PhD3 ,J Orthop Sports Phys Ther • Volume 36 • Number 5 • May 2006



Sn Sp +LR -LR

Anterior drawer test, without anesthesia, whole group.

Pooled 55 92 7.3 0.5

Lachman test, without anesthesia, whole group.

Pooled 85 94 10.2 0.2

Pivot shift, without anesthesia, whole group.

Pooled 24 98 8.5 0.9

Anterior drawer test, with anesthesia, whole group.

Pooled 77 87 5.9 0.4

Lachman test, with anesthesia, whole group.

Pooled 97 93 12.9 0.1

Pivot shift, with anesthesia, whole group.

Pooled 74 99 20.9 0.3


Remember Sensitivity (Sn) and Specificity (Sp) only describe how abnormality, in this case a rupture of the ACL, predicts a test result.(Deeks 2004)

However, for clinical practice it is essential to know how a test result predicts abnormality.

Likelihood ratios provide this information.

According to a prospective investigation from Noyes et al (1980)
44.0% of patients with acute knee injuries (defined as individuals who suffered a traumatic knee injury associated with a rapid onset of swelling [ie, a hemarthrosis] with or without the sensation of a pop) have a completely torn ACL.

In other words, the pretest probability of having an ACL rupture in these patients is 44.0%.

From above, in acute cases the LR+ of the Lachman test is 9.4 (95% CI, 0.4-210.0). From this value the posttest probability
can be calculated, which is 88.1%. See nomograph below.


It can be seen that using Lachman’s test in an acute knee with sweeling can take your pre test odds of 44% and increase them to
88.1%.

If you do the pivot shift test under anesthetic the LR is 20.9, pre test odds are again 44% but post test odds increase to 95%.

From this example you can see the usefulness of knowing the pre test odds and likely hood ratio for your tests in musculoskeletal medicine.


Using the nomogram you can apply the information above. Line A is the pre and post test odds for Lachman's test with out anesthetic.



References:


Bogduk N. Truth in Musculoskeletal medicine Truth in Diagnosis- Validity. Australasian Musculoskeletal Medicine. May1999

Deeks JJ, Altman DG. Diagnostic tests 4: likelihood ratios. BMJ.;329:168-169. 2004


Fritz J , Wainner RS. Examining Diagnostic Tests:
An Evidence-Based Perspective. Physical Therapy . Volume 81 . Number 9 . September 2001

Noyes FR, Bassett RW, Grood ES, Butler DL.Arthroscopy in acute traumatic hemarthrosis of the knee. Incidence of anterior cruciate tears and other injuries. J Bone Joint Surg Am;62:687-695, 757. 1980


Friday, April 10, 2009

Danish Physiotherapy Conference (Fagfestival)

If you are interested in viewing my presentation on "Differentiating Neck from Shoulder Problems", at the Danish PT national Conference in Odense, Denmark, or you are interested in looking at David Butler's or Ann Cools presentation at the same conference click on this link: http://www.fysio.dk/sw110086.asp

Have a great Easter.

Wednesday, April 8, 2009

Some patient centred thoughts

" Offer patients solutions
to their probelms,
not more problems"

"Patients don't care how much you know,
until the know how much you care."


Patients have all the answers,
they just don't have all the solutions"

" Empowering patients is hard,
you have to give up something yourself."

" You should listen twice as much as you talk, that is why you have two ears and one tongue."

Saturday, April 4, 2009

Ethos, Pathos, Logos.

Ethos, Pathos, Logos are three very important words, in fact I propose they are the three words which will allow you to develop a "Patient Centred" approach to your clinical practice.

Ethos: Gain thrust. It forms the root word for "Ethics".

Pathos: First seek to understand. It forms the root for the word "Empathy".

Logos: Then to be understood. It forms the root for the word "Logic".

At your first meeting with a patient it is essential to gain their trust. Without trust even the best treatment may fail. Successful treatment requires synergy between patient and therapist.

First seek to understand, then to be understood. This is one of Stephen Coveys "Seven Habits"

I believe it is an essential tool in patient history taking, examination ans self treatment.

I have developed the "INTENT / RELEVANCE" cycle to assist therapists in developing the Pathos, logos in their patient interactions.

Intent is knowing why you are asking a question, relevance is the who, where, what, when and how of the patent's condition. In English relevance means pertaining to the matter at hand.

To use the Intent/relevance cycle you must first accept that when you ask a question with intent you will know why you are asking the question. Then you must stay silent and listen to the patient relevant answer, then you will form your next clinical question from the patient answer.

Too many therapists are forming their next question whilst the patient is trying to answer the last question.

Think; LISTEN and SILENT are made up of the same six letters for that very reason. To truly listen requires you to be silent and allow the patient to give your their relevant information.

Your next question comes from the patients last answer, hence Intent and Relevance form a circle and allow you to use pathos and logos in a cycle.

Remember His (her) Story is what you are trying to take not MY-story which spells mystery.

I would propose that the intent/relevance cycle also applies to your clinical testing. Choosing tests with intent will allow you to collect relevant meaningful data and set relevant clinical baselines for retesting.

I would also propose that the patients own baselines are the most accurate and relevant to the current condition and will be the best to measure treatment outcome.

So remember three simple words; Ethos, Pathos, Logos may improve your ability to practice as a patient centred therapist.

Saturday, March 28, 2009

David Squared


I think I'm going to have to get myself some glasses. Elton John may have some that might work.


One of these Davids is a famous Therapist, the other is me.
I have posted a short version of my Retlouping video on YouTube you can watch it by clicking on this link: http://www.youtube.com/watch?v=u3BwXOkbWCo



Friday, March 27, 2009

Greetings from the Danish Fagfestival 2009




Please enjoy the content of this page. The information on RETLOUPING is at the end of the page.

I hope you enjoyed the Fagfestival presentation.

Please feel free to e-mail me.

Kind regards,

David


Sunday, February 24, 2008

An Evidence Based Approach to Treating Tendon Problems A new model for clinical reasoning..

An evidence based approach to treating tendon problems.
Introducing a new clinical model for diagnosis and management of muscolskeletal problems.
By David Poulter PT


A Simple proposition: Pain does not equal inflammation.

There is a lot of evidence to suggest that 90% of what we thought was tendonitis is in fact tendonosis. The troubling aspect of this evidence is that 90% of patients presenting with tendon problems are receiving the wrong treatment. (12,16) Tendonosis is being treated as though it is an acute inflammatory condition. Current evidence suggests that most tendon problems lack an inflammatory mediator (prostaglandin E2). There is some discussion as to whether tendonitis is a precursor to tendonosis, but the current evidence leans towards the hypothesis that it is not.(2,16,17)

The literature also suggests that we have been treating everything as though it was inflamed. Recent studies have demonstrated that NSAIDS used in the early treatment of tendon problems are ineffective and may retard the healing process. There is evidence that used later in the condition they may be of some benefit.(9,10)

Simply put tendosis is a painful condition brought on by overloading connective tissue, which cannot keep pace with remodeling. There is no evidence of inflammatory cells in tissue samples; hence the condition does not follow a normal healing cycle. There is strong evidence of organized cell death “apoptosis” and increased tenocite activity, with disorganized collagen alignment. There is also strong evidence of neovascularization around the affected tendon.(2,3,7)

The literature suggests that neovascularization (new immature blood vessels) may be the cause of some of the pain, there has been work done by Alfredson and his group on sclerosing the vessels, which leads to athletes becoming pain free. These neovessels are also enriched with new nerves, which may also contribute to the pain.(4)

There is also strong evidence that the neurotransmitters Glutamate and Substance P have been found in high concentrations, in people with tendonosis, and a lack of prostaglandin E2. The relationship to pain production is still not clearly understood.(2,3,8,9)

Alfredson’s group in Sweden has done a lot of work on using eccentric loading to treat tendonosis, with good outcomes.(1,14,18) Purdham has also done work at the Australian Institute of Sport using incline eccentric squats for knee tendonosis with good results.(26) There is also strong evidence that eccentric programs have good effect on treating hip adductor problems, lateral elbow problems and shoulder tendonopahy.(14,19,12,26,27,28,29)

Current research also demonstrates good outcome from using Nitric oxide (glycerin trinitrate patches) in the treatment of tendonosis of the elbow, shoulder and Achilles.(20,23,24,25)

The Active/ Inactive model

I have propsoed a simple model known as the Active / Incative model for clinical reasoning. The model is based on the symptomatic and mechanical responses of patients to loading.

Definitions:

Mechanical Loading Strategy = Repeated movements, static
positions, functional tasks, manual techniques.

Active Condition = During the application of certain mechanical loading strategies there will be a change in the symptomatic presentation and / or the mechanical presentation, this change will remain on cessation of the loading strategy.

Inactive Condition = During the application of certain
mechanical loading strategies there may be a change in the symptomatic presentation and / or the mechanical presentation, but the change will never remain on cessation of the loading strategy.

The active/Inactive model is represented below in figure 1.



Figure 1. Poulter (c) 2008

The Active/Inactive model can be used to classify common musculoskeletal problems. This allows for simple treatment strategies to be carried out.

It can be seen that in the Active/Inactive model "Tendonosis" is classified as an Inactive pathalogical condition, which comes about as a result of Wolff's law. Wolff's law simply put states "Form follows Function". Tendonosis put in simple terms is the tissues failure to remodel succesfully to an external load being applied. The collagen disaray, cell apoptosis and glutimate presence are all refelctions of Wolff's law and the tissues failed adaptation to loading. (11, 12, 15)

We often give the beneficial effects of Wolff's law the label "Remodelled", the adverse effects are often given the label "Degenerated".

Good news: Even though Tendonosis is labelled as a degenerative condition it can be remodelled using the correct eccentric loading strategies. (1,2,3,4,5,,6,12,13)

The active/inactive model can be used to classify all common muskuloskeletal conditions, based on their symptomatic and mechanical responses to loading.

On the left side of the model I propose three ways that tissue can be damaged to lead to an active condition.

1. Over stressing tissue. Tissues have a stress strain curve which represents their response to external loading. Most tissues go through and elastic, to palstic, then failure phase. Over stressing tissue can lead to permenant deformation of the tissue, without necessarily breaking the tissue. If the tissue has an innervation this may case pain and micro fracturing of the tissue.

If the tissue doesn't have an innervation then it may displace (nucleus palposus), tear (labrum of hip or shoulder), or over stretch (inner annulus of disc) and lead to pain by placing stress on an innervated structure.

2. Inflammation. Inflammation can be casued by systemic auto immune disease such as Rheumatoid arthritis, Ankylosing Spondylitis, Psoriatic arthristis, Lupus, Reiters Disease, Stills Disease and other common arthitidese. It is well documented that these conditions go through active cycles and remissions.

3. Trauma. Simply put "tissue fracture". This leads to bleeding, clot formation and then the normal healing cycle. The first phase of trauma invovles inflammation caused by the tissue damage.

On the right hand side of the model there are three ways of returning to inactive.


1. Healing. There are recognised phase to the healing process. It is important to remember that each pahse is a predomination and that the other phses are taking place at a lower level all through the healing process.

Phases of Wound Healing
The entire wound healing process is a complex series of events that begins at the moment of injury and can continue for months to years. This overview will help in identifying the various stages of wound healing.

I. Inflammatory Phase
A) Immediate to 2-5 days
B) Hemostasis
Vasoconstriction
Platelet aggregation
Thromboplastin makes clot
C) Inflammation
Vasodilation
Phagocytosis

II. Proliferative Phase or Fibroplastic Phase.
A) 2 days to 3 weeks
B) Granulation
Fibroblasts lay bed of collagen
Fills defect and produces new capillaries
C) Contraction
Wound edges pull together to reduce defect
D) Epithelialization
Crosses moist surface
Cell travel about 3 cm from point of origin in all directions

III. Remodeling Phase
A) 3 weeks to 2 years
B) New collagen forms which increases tensile strength to wounds
C) Scar tissue is only 80 percent as strong as original tissue


2.Natural resolution: Natural resolution is different from healing becasue it does not go through a formal process of stages and does not take 6-12 weeks to show results functionally. Mytosis is a form of repair which can not be discribed in terms of healing, molecular reconstitution due to water reabsorption, hysteresis after tissue creep, realignment of tissue after stress are all examples of natrual resolution.

Non vascularized, non innervated tissues can not heal but they can under go remodeling and change their structure molecularly. They can also be affected by creep and hysteresis.

Resolution of pain and stiffness after a manipulation can not be described in terms of healing, but is a form of natural resolution.



3. Treatment: "Removal of the nasty things to provide an optimal environment for recovery."


Follows the D.Re.Ma.R concept of treatment. (Poulter 2008)


Diagnose, Reduce, Maintain, Restore Function


Classification using the active / inactive classification system



1. I.D.I.O.T.

Victims of creep also known as I.D.I.O.T. syndrome. Sustained loading with g
(gravity) over Time of normal tissue leads to
CREEP and the nociceptive system kicks in to warn of impending
damage to the tissue.

“I Do It Over Time”

This is superimposed on other problems.

This class is inactive non pathological


2. Mal-adaptation

This occurs as connective tissues (including scar) obey Wolff’s law. Generally this can be called other names such as degeneration, adaptive shortening, adhesions, “dysfunction”, instability from degenerative changes can also be included in this class.

The recent literature has also suggested that common tendon pathologies, and even muscular, capsular and ligamentous problems, are caused by an abortive remodeling process which cannot keep pace with the stress applied to them.
The pathology produces is Tendonosis.

Tendonosis is an inactive tendon pathology. ( Khan 2000, Cook 2000 )

Two ends of the spectrum of mal -adaptation are shortened scar or adhesion , restricting motion, or degenerative changes leading to abnormal excessive motion, often classed as instability, with tendonois changes in the middle.

Stable ………………Mal-adaptation………………unstable
(inactive pathological) (inactive pathological )
(Mechanical)


3. Re-arrangement


This class is defined by its active symptomatic and mechanical presentation. Hypothetically this is over stretching of the contents or supporting structures of a joint, leading to temporary or even permanent incongruity of the joint. It is often labeled as, subluxation, dislocation, instability, “derangement”, internal derangement.

Active pathological (mechanical primary, with possible secondary chemical)

4. Trauma

Simply put this involves tissue fracture, leading to a cascade of chemically mediated events, cardinal signs being, heat, redness, swelling and pain. (Calor, rubor, tumor, dalor). Trauma can range on a spectrum from mild to major, depending on the degree of damage and extent of the tissue damaged.

Active pathology (Mechanical leading to primary chemical, secondary mechanical from tissue swelling)




Mechanical Treatment Approach

I.D.I.O.T. (victim of creep): Avoidance of provocative postures and positions. Postural alteration, slouch overcorrect, regular interruption of sustained postures.

Mal-adaptation (with restrictive loss of function): “REMODEL.” Controlled return of stress / function using HURT not HARM principle. Understanding the patient is essential, it takes time to produce a restriction of function due to soft tissue changes and the patient is generally fearful and avoiding pain.

Note you cannot stretch mal-adapted tissue; it has to be remodeled over time. Patient generated forces are adequate to bring about remodeling over time if the appropriate functional stress is applied often enough.

Mal-adaptation (with instability): The treatment of mal-adaptation with excessive motion or instability is postural control and stability exercises (strengthening of postural control muscles). Neuromuscular re-education is often required to allow stability during function.

Mal-adaptation Tendonosis, ligosis, myosis, fasciosis.: The treatment of the “Osis”
is similar to remodeling the short contracted tissue form of mal-adapted tissue. The affected tissue needs loading in a gradual and repetitive fashion. “Eccentric loading”
allows us to apply load to the tenonosis to begin remodeling. In the case of myosis eccentric muscle work and often isometric muscle work allows remodeling to be achieved.
It is important to keep in mind the HURT not HARM system of applying load to the tissue.
Remodeling of and “osis” is a painful procedure and can take many months. Patient education and expectations should be addressed as part of the overall treatment strategy.

Rearrangement: The treatment of rearrangement follows the simple orthopedic principle of D.R.eM.aR.:
Diagnose, Reduce, Maintain & Restore Function. Patient self generated repeated movement to end range; static positions; patient forces and therapist forces are all used in the reductive stage. The P.O.O.M.M. Patient Centered Force Progression Model is followed.
(Over pressure can also be synergistic)Patient generated
Over pressure (Patient)
Over pressure (Therapist)
Mobilization
Manipulation.

Postures and positions are used in the maintenance stage.

Patient self generated repeated movements are used in the restoration of function stage.

Trauma (Tissue fracture): The treatment of trauma follows the D.R.eM.aR principle.
During the reduction phase the R.I.C.E. principle can be followed. (Rest, Ice, Compression, Elevation), in the first few days. Movement testing should begin as soon as possible, using the Hurt not Harm principle. A sign that movement is indicated is that the patients pain becomes intermittent.

Movement in the presence of healing is indicated as long as the symptomatic response to loading is monitored closely. Early controlled movement will give the message to the healing tissue to lay down in a functional orientation and prevent the development of mal-adaptation.


References:

1.Alfredson H et al: Heavy-Load Eccentric Calf Muscle Training For the Treatment of Chronic Achilles Tendinosis. THE AMERICAN JOURNAL OF SPORTS MEDICINE, Vol. 26, No. 3 1998

2.Alfredson H. In situ microdialysis in tendon tissue: high levels of glutamate,but not prostaglandin E2 in chronic achilles tendon pain. Knee Surg Sports Traumatol Arthrosc;7:378–81;1999.

3.Alfredson et al In vivo investigation of ECRB tendons with microdialysis technique—no signs of inflammation but high amounts of glutamate in tennis elbow. Acta Orthop Scand; 71 (5): 475–479;2000

4.Alfredson H, Ohberg L: Neovascularisation in chronic painful patellar tendinosis--promising results after sclerosing neovessels outside the tendon challenge the need for surgery. Knee Surg Sports Traumatol Arthrosc. 2005

5.Alfredson H, Ohberg L: Sclerosing injections to areas of neo-vascularisation reduce pain in chronic Achilles tendinopathy: a double-blind randomised controlled trial. Knee Surg Sports Traumatol Arthrosc. 2005


6.Alfredson H, Ljung BO, Thorsen K, Lorentzon R: In vivo investigation of ECRB tendons with microdialysis technique--no signs of inflammation but high amounts of glutamate in tennis elbow. Acta Orthop Scand. 2000

7.Alfredson H: Chronic tendon pain--implications for treatment: an update. Curr Drug Targets. 2004

8.Alfredson H, Lorentzon R: Chronic tendon pain: no signs of chemical inflammation but high concentrations of the neurotransmitter glutamate. Implications for treatment? Curr Drug Targets. 2002

9.Almekinders LC et al. An In Vitro Investigation Into the Effects of Repetitive Motion and Nonsteroidal Antiinflammatory Medication on Human Tendon Fibroblasts. The American Journal of Sports Medicine 23:119-123 (1995)

10. Almekinders LC et al. Etiology, diagnosis, and treatment of tendonitis: an analysis of the literature. Med Sci Sports Exerc. ,Aug;30(8):1183-90,1998

11.Cook JL et al: Overuse Tendinosis, Not Tendinitis Part 2: Applying the New Approach to Patellar Tendinopathy. THE PHYSICIAN AND SPORTSMEDICINE - VOL 28 - NO. 6 - JUNE 2000

12.Cook JL, Khan KM, Purdam CR. Conservative treatment of patellar tendinopathy. Physical Therapy in Sport;2:54–65; 2001

13. Gotoh M, Hamada K, Yamakawa H, et al. Increased substance P in subacromial bursa and shoulder pain in rotator cuff diseases. J Orthop Res,16:618–21.1998

14. Holmich P et al. Effectiveness of active physical training as treatment for longstanding adductor-related groin pain in athletes: randomised trial. THE LANCET • Vol 353 • February 6, 1999

15. Khan KM, Cook JL, Bonar F, Harcourt P, Astrom M: Histopathology of common tendinopathies. Update and implications for clinical management. Sports Med. 1999

16.Kahn et al .Where is the pain coming from in tendinopathy? It may be biochemical, not only structural, in origin. Br. J. Sports Med.34;81-83;2000

17. Khan KM et al: Overuse Tendinosis, Not Tendinitis Part 1: A New Paradigm for a Difficult Clinical Problem. THE PHYSICIAN AND SPORTSMEDICINE - VOL 28 - NO. 5 - MAY 2000

18. Knobloch et al Eccentric Training Decreases Paratendon Capillary Blood Flow and Preserves Paratendon Oxygen Saturation in Chronic Achilles Tendinopathy. JOSPT. May 2007

19. Macintyre IG. Heavy Eccentric Loading for a Recalcitrant Case of Lateral Epicondylosis in a Hockey Player: A Case Report . Graduate Education and Research, Canadian Memorial Chiropractic College,2007

20. Murrell GA. Using nitric oxide to treat tendinopathy. Br. J. Sports Med.;41;227-231;2007

21. Ohberg L, Alfredson H. Effects on neovascularisation behind the good results with eccentric training in chronic mid-portion Achilles tendinosis? Knee Surg Sports Traumatol Arthrosc. 2004 Sep;12(5):465-70. Epub 2004

22. Ohberg L, Lorentzon R, Alfredson H. Eccentric training in patients with chronic Achilles tendinosis: normalised tendon structure and decreased thickness at follow up. Br J Sports Med;38(1):8-11, Feb 2004

23. Paoloni JA, Appleyard RC, Nelson J, et al. Topical nitric oxide application in the treatment of chronic extensor tendinosis at the elbow: a randomized, doubleblinded, placebo-controlled clinical trial. Am J Sports Med;31:915–20,2003

24. Paoloni J, Appleyard R, Murrell GAC. A randomized double-blind placebo
controlled clinical trial investigating the use of topical nitric oxide
application in the treatment of Achilles tendonitis. J Bone and Joint Surg
(Am);86-A:916–22,2004

25. Paoloni JA, Appleyard RC, Nelson J, et al. Topical glyceryl trinitrate application in the treatment of chronic supraspinatus tendinopathy: a randomized, doubleblinded, placebo-controlled clinical trial. Am J Sports Med ;33:806–13, 2005

25. Purdam CR et al: A pilot study of the eccentric decline squat in the management of painful chronic patellar tendinopathy. Br J Sports Med ;38:395–397; 2004

26. Scott A, Khan KM, Roberts CR, Cook JL, Duronio V. What do we mean by the term "inflammation"? A contemporary basic science update for sports medicine. Br J Sports Med. 2004

27. Tyler T et al The Effectiveness of a Preseason Exercise Program to Prevent Adductor Muscle Strains in Professional Ice Hockey Players. The American Journal of Sports Medicine 30:680-683 (2002)

28.Young et al Eccentric decline squat protocol offers superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players. Br J Sports Med;39(2):102-5; Feb 2005

29. Yuan et al. Apoptosis in rotator cuff tendonopathy. Journal of Orthopedic Research. Vol26, no 6 1372-1379; 2006