The biggest challenge in diagnosing septic arthritis is to think of it. Once you think of it, there is a diagnostic process that you activate. The second biggest challenge is that that diagnostic process we learn in training is flawed. We have no alternatives right now, so I will share with you my thoughts on how we should use our judgment as clinicians.


Triggers to consider septic arthritis essentially are the same triggers as infection anywhere. Celsus’ cardinal signs of inflammation are dolor (pain), calor (warmth), rubor (redness), tumor (swelling). Some authors have written that fluor (flow) should be the 5th cardinal sign and in this case the effusion is one of the most important clinical signs.


The detection of effusion at the bedside has been covered elsewhere but includes inspection, palpation, and milking. Smaller volumes of fluid are harder to detect. Ultrasound can be utilized to improve our accuracy.


The clinician generates hypotheses at the bedside and then circles back to revisit risk factors. This is an underappreciated process that deserves more attention. The following risk factors have high specificity:



-joint surgery (mainly recent)

-joint prosthesis (at any time)


There are others but those are the main ones. You might think of it as “compromised immune system” and “compromised joint.” If it helps you in remembering this, recall that the synovium is a vascular tissue. It lacks a basement membrane (which tends to filter out bacteria in other tissues, like the cornea). The joint relies on the immune system to protect us from bacterial translocation. Recall also that bacteria love to find crevices to hide in. A disrupted joint, or a compromised immune system creates the setting for septic arthritis.


They don’t all have to have those high risk features though. Often the clinician is left with enough suspicion to pursue a risk stratification process before considering a tap. In low risk patients that process can involve inflammatory markers (traditionally WBC, CRP, ESR, with emerging roles for procalcitonin and perhaps other markers) to lower your suspicion back below the threshold of further testing. I recommend you use as many of these as you need to reassure you in a low risk patient that there is no infection. All of them have limitations but if the results are normal, you are greatly reassured.


For patients where doubt continues to exist, the diagnostic pathway for septic arthritis ends in arthrocentesis, though its results may be less clear than we realize. Common practice is to use synovial blood counts (often 50K) as disease-defining, which does not actually work very well. Synovial WBC cutoffs at all levels will both miss and overcall septic arthritis. Even if you use the cutoff as 25K, it still misses as many as 1/4 of all cases, one prospective study said it would miss more than 1/3 of all cases (Margaretten JAMA2007). Meanwhile there will continue to be patients with WBC above 50K who have other causes (gout for example).


The gram stain sensitivity is as low as 40% (Ross Infect Dis Clin North Am2017). If you have strong suspicion based on risk factors, drain the joint and have them follow up in 24 hours, giving antibiotics while awaiting culture results.



-Septic arthritis is considered when the patient has an inflamed joint (effusion, warmth, pain).

-Inflammatory markers, if all normal, can lower your concern enough in a low risk patient to rule out disease.

-Risk factors (compromise of joint, compromise of immune system) may be more important than the other tests.

-Synovial WBC has significant limitations in sensitivity and specificity, and is not a disease-defining reference standard.


Selected References:


Septic Arthritis of Native Joints.

Ross JJ.

Infect Dis Clin North Am. 2017 Jun;31(2):203-218. doi: 10.1016/j.idc.2017.01.001. Epub 2017 Mar 30.


Does this adult patient have septic arthritis?

Margaretten ME, Kohlwes J, Moore D, Bent S.

JAMA. 2007 Apr 4;297(13):1478-88. Review.

PMID: 17405973



A patient presents with a mid forearm fracture. Reduction is tough because it is 100% displaced. Unlike distal fractures, you can not grab the bone as it is surrounded by muscle. It is hard to pull enough traction to reapproximate. Now what?


Try angling more during your reduction, exaggerating the angulation. Now it is slack enough you can put the distal piece on the proximal piece. Use your other hand to guide it on manually. Once the two pieces touch each other, simply straighten the bone out.


You try this and are able to secure adequate reduction. The patient now has a better chance of receiving adequate reduction without surgery.



If you can not pull traction to reapproximate fractures, try angling the fracture to give it slack, then fit the fragments together before restoring alignment.


A patient presents with a recurrent anterior shoulder dislocation. Milch fails but Spaso works. The next month she is back and the procedure feels different, with more resistance. This time Spaso fails and Milch works. Same shoulder, so what is different? Why did the efficacy reverse?


Milch’s 1938 article started with a question: why do some reductions seem impossible and then under general anesthesia they become very easy, almost going in spontaneously? It was the muscle and tendon opposition, he concluded, so his technique focused on putting the patient in the muscle neutral position overhead (hanging from a limb position). The various shoulder muscles would share equal stress and equal angles.


Milch’s idea has probably not yet been fully fulfilled – it was the idea that shoulder reduction is not about overcoming force but about untangling the humeral head from the adjacent muscles, tendons, and soft-tissues. That was the same idea that inspired Kocher.


We have all had the tough shoulder that would not go in with technique A, but after trying technique B, a second attempt with A yielded an effortless reduction. There seems to be an unlocking of the soft structures that occurs.


Now as to the unlocking. I suspect there is advantage in the difficult shoulder to running through a variety of techniques. Ideally we would know which soft structures are causing the locking, but the literature lacks consensus and I do not know to resolve that. So I run though a variety of techniques.


This is reductionistic but you can think of all techniques as the application of external rotation in different positions.


Kocher is external rotation in the adducted humerus, as are all the derivative techniques.


Milch is external rotation in the abducted elevated humerus (technically he advocated doing the external rotation on the way up).


Spaso is external rotation in the forward flexed shoulder.


Back to the bedside. Its your next shoulder attempt. The shoulder is locked in internal rotation. Your goal is to get it into external rotation. You try Kocher but there is too much resistance to external rotation. You laterally abduct to Milch and you came close but did not fully reduce the shoulder. Finally, you perform forward flexion (Spaso) which also does not work. You then go back to Kocher, which this time was successful.


Take Home Points:

-The obstruction to shoulder reduction is not bone position but soft structures

-The obstruction can apparently be unlocked through applying external rotation in various positions through the range of motion

-If your favorite technique does not work, range the shoulder, externally rotate, and try it again.

Check out for more on Milch. If the link does not work, here is the location.



The Kocher technique, one of the oldest and most popular techniques, was developed for the subcoracoid anterior dislocation. Review Neil Cunningham’s resources at for insight on this, as well as his translation of the original Kocher article.


The goal of Kocher’s method, which was worked out on cadavers in 1870, is to roll the greater trochanter of the humeral head on the glenoid rim. It might have been named the “shoulder rim roll.” Here are the steps:


1) Adduct the elbow all the way to get the greater trochanter right next to the glenoid rim.

2) Externally rotate to roll the greater trochanter on the glenoid rim.

3) Forward flex the shoulder (sagittal plane) to tip the humeral head back toward the socket.

4) Internally rotate to complete the reduction.


Kocher’s words:

“Pressing the arm bent at the elbow towards the body, turning outward until resistance is felt, lifting of the outwardly rotated upper arm in the sagittal plane as far as possible, and finally slowly turning it inward” (translation by Cunningham)



The subglenoid dislocation will not be resolved with the Kocher technique because the external rotation phase will not latch onto anything. Kocher himself in his article specified that this was for subcoracoid dislocations, and said “the more therefore the head has departed from the coracoid process toward the interior … the less can be expected from the method.”



-Make sure you fully adduct the elbow first.

-Avoid traction, which is what creates the need for sedation(Chitgopar Injury 2005).

-Avoid sedation. This is the best way to avoid too much force. Kocher’s method excluded the use of force. Perpendicular forces of opposing muscles can lead to fracture. If you get resistance, use another technique.



-Kocher’s shoulder reduction was originally intended for subcoracoid dislocations, not for subglenoid.

-Do not use force with Kocher’s method.


References: (see the lectures and translation of the original Kocher article)

Chitgopkar SD, Khan M. Painless reduction of anterior shoulder dislocation by Kocher’s method. Injury. 2005;36:1182-4.


We think of the foot as a simple thing but it actually comprises one fourth of all the bones of the body, with 26 overall. Although some stability comes from the arch structure (the Roman arches did not require mortar) most of the stability of the foot is ligamentous.

It therefore should not be surprising that diagnosing foot injury and predicting complications is difficult. Ligaments are essentially invisible on xray. Weight-bearing radiographs, recommended by the American College of Radiology, are difficult to order on emergency department patients in acute pain and MRI is usually not available. Thus, some of these patients will not be diagnosable by us but we can protect these patients through clinical suspicion and follow-up.

After negative xrays. acute traumatic midfoot pain is usually a ligament injury of one sort or another. If stable, it will likely heal. If it is a third degree injury and unstable, it may require surgery.

The Lisfranc joint is eponymous for Jacques Lisfranc who treated a Napoleonic soldier who had fallen off his horse with his foot caught in the stirrup. Ultimately the patient developed gangrene and required amputation at what became known as the Lisfranc joint complex (tarsometatarsal joints).

Today we hear about injuries in the news if you watch football, especially in defensive linemen who pivot on the toes, stressing the tarsometatarsal joints. As they twist in this equinus position to get around the offensive tackle, the Lisfranc joint can rupture.

There are not sufficient studies on physical diagnosis of the Lisfranc joint but the review articles tend to recommend stressing the midfoot with lateral and medial stress, abduction and pronation, etc. If you have trouble remembering all the Latin words, just do what you do with stress testing of any orthopedic limb – check it in the x, y, and z axes.

Take Home Points:

Recognize midfoot pain as a potentially ligamentous injury

Palpate the tarsometarsal joints

Stress the tarsoemetarsal joints in the X, Y, and Z planes, if the patient allows


An elderly female presents after a fall. You were concerned about hip fracture but the x-rays were negative. You go back to examine her and she is able bear weight but she has a very slow and antalgic gait. You order a CT scan of the hip and this also comes back normal. You go back to examine her wondering whether you can use physical diagnosis to exclude a fracture.


X-rays are only 90% sensitive for fractures, and CT has well-known limitations, though its sensitivity is not as well-described (Cannon J JEM 2009).  MRI is currently considered the gold standard, but is less available in the ED for this condition.


Physical examination techniques for discovering an occult hip fracture include slow and gentle palpation to isolate the area of maximal tenderness. Internal and external rotation isolate hip joint movement. Ambulation is essentially a stress test of the hip, performed when the patient does well on the other tests. These tests have not been studied in an undifferentiated ED population with hip pain after a fall.

In any limb I suspect of having a fracture I try to hold the limb at non-painful areas above and below and then apply stresses in the X, Y, and Z planes (twisting, back and forth, and side to side). Exacerbation of pain suggests a fracture.


Being good at physical diagnosis doesn’t mean using it to get the answer. Sometimes it means knowing it isn’t capable of giving you the answer.

If an elderly patient has persistent hip pain after a fall and negative x-rays, it might be a fracture. Period. This does not mean they all need admission to the hospital, but whatever plan is arranged must take this fact into account.

Can the patient still bear weight? So could 7/26 patients found to have an occult hip fracture in a retrospective study (Hossain Injury 2007). Does the patient have no pain with passive rotation of the hip? This is true of 10/26 patients with occult hip fracture. Can the patient perform a straight leg raise? So could 13/26. How about axial loading? 7/26 had no pain with this.

The patient with hip pain who is unable to walk usually is admitted for MRI the next day. But even the patient who CAN walk might still have a fracture. If discharge is chosen, the patient should be informed of this possibility, given crutches, and told to follow-up within a few days with the primary physician for reevaluation. If the patient is better, no MRI is needed. If the patient is still having significant pain, MRI is indicated.

The patient was discharged home. The hospitalist felt that she did not require admission for MRI because she was able to walk and had negative xrays and CT. The MRI was not done. A week after discharge from the ED she took a normal step and her femoral neck gave way to a displaced fracture.

Take home points:

-Even if the patient with hip pain can walk, he or she may have a fracture. Close follow-up is needed for elderly patients with persistent hip pain after a fall. Non-weight bearing status should be considered in selected patients.


The neurological examination is relative to the pathology you are investigating. This should not be used in a cut and paste fashion but rather for reference.



Hip flexion “pull your knee to your chest” (L2/3) 5/5

Hip adduction “pull your knees into each other” (L2/3) 5/5

Hip abduction “pull your knees apart” (L4/5/S1) 5/5

Hip extension “pull your thigh back” (L4/5) 5/5

Knee extension “hold your knee straight” (L3/4) 5/5

Knee flexion “pull your heel to your bottom” (L5/S1) 5/5

Ankle dorsiflexion “pull your foot up” (L4/5) 5/5

Ankle plantarflexion “step on the gas” (S1/S2) 5/5

Great toe dorsiflexion “pull your big toe up” (L5) 5/5

Great toe plantarflexion “squeeze your big tow down” (S1,S2) 5/5

Anal tone – (S2/3/4) 5/5



Light touch (pinprick vs ice vs proprioception vs vibration if evidence of pathology found)

L1 – inguinal ligament

L2 – medial thigh

L3 – distal thigh

L4 – medial leg and dorsal foot

L5 – 1st web space, lateral foot

S1 – plantar foot

S2 – popliteal fossa, posterior thigh

S3/4/5 – perianal area




Patellar – L3/4

Medial hamstring reflex L5

Ankle – S1


A 2 year old presents with leg pain and a limp after slipping on a “slip and slide” water toy slide. X-rays are negative. The child will step when asked but will not walk on his own. Is this an occult fracture?

This is a situation where the reference standard, radiography, has limitations in sensitivity. Studies show that using alternative tests reveal evidence of fracture, such as hematoma elevation on ultrasound (Lewis J Clin Ultrasound 2006) or MRI or delayed radiographs.

You go back and examine the leg, placing “bowing” stress on the leg. Sometimes it elicits pain and sometimes it does not. You press on different parts of the leg and it is difficult to localize but there does seem to be the most pain on the distal tibia.

You then twist the leg and foot spirally and the child shouts in pain. You make a clinical diagnosis of Toddler’s fracture. On follow-up, the mother reports that the child reverted to crawling for about 4 weeks before gingerly walking and then returning to normal use of the leg in about 6 weeks. Repeat xrays in the primary physician’s office remained negative. This was an occult tibial fracture.

Take Home Points

Negative x-rays do not rule out fracture

Twisting a long-bone can elicit pain from an occult fracture, especially one in a spiral pattern


A patient presents with a laceration to the flexor side of her left forefinger. The student tells you function was normal.

“How did you determine that?” you ask.

“Range of motion.”

You ask the patient to repeat the range of motion test, but this time you apply active resistance and simultaneously check the opposite side for comparison. There is significant weakness on the left compared to the right. You just discovered a partial tendon laceration and prevented an easy misdiagnosis.

Range of motion is not sufficient to rule out a partial tendon laceration. Strength testing picks up partial lacerations because some of the muscle fibers were connected to the part of the tendon that was lacerated. You can’t always visualize the laceration so this strength testing a useful part of the examination.

There are some interesting articles about this that indicate range of motion can not even be used to rule out a complete tendon laceration. A patient had complete transection of the FDS and FDP yet intact range of motion via the vincula (connections between tendons). Resisted range of motion made the diagnosis (Sasaki J Hand Surg Br 1987)

Take Home Points:

-For suspected tendon laceration, don’t just test range of motion, test resisted range of motion


A mother brings her 2 year old child in for a limp. The student believes the patient has ankle pain because she cried when she grabbed the ankle. After that she cried with everything. After calming the child down you watch her walk and it is abnormal but you wonder how to interpret this.


The last time I tried really hard to analyze gait and make recommendations, it was so complicated that no one could remember it. I now have a more simple approach. An abnormal gait is either neurologic or orthopedic. If there is pain, it tends to be orthopedic. No pain suggests neurologic.


Next, don’t just watch the gait. Imitate it. Follow the child. This allows your proprioceptive neurons to do the thinking for you.


When you do that on this child you see she is splinting her hip. You examine the calmed child and get good range of motion of the ankle and knee. Internal and external rotation of the hip seems to cause discomfort. Now your differential is transient synovitis vs septic arthritis and you proceed from there.


Take Home Points:

Painful gait abnormalities are usually orthopedic. Painless are usually neurologic.

Walk the walk: imitate the gait so you can feel what they are doing with their gait