MCQs – Upper Extremity/Elbow 1

MCQs-UE/elbow 1
– with respect to the anterior band of the medial collateral ligament – the origins of both the anterior and a posterior bands lies just posterior to the axis of rotation, and hence both are a bit tighter in flexion than in extension. Its lack of isometricity makes it sometimes necessary to release some of the MCL when doing an elbow release (unlike the lateral collateral – which is isometric).

– the posterior elbow capsule is also tight in flexion and thus has an important role as a static stabilizer too

– Baumann’s angle is about 72 degrees – the angle between the physeal line of the lateral condyle and the humeral shaft (does not equal the carrying angle)

– through and through gunshot wound to the forearm with nerve injury – expectant splinting of the wrist and hand; anticipate delayed exploration of the wound if the nerve doesn’t recover. Most nerve injuries in this setting are not transactions – they are concussive injuries from the zone of injury.

– high radial nerve palsy: PT to ECRB; FCU or FCR to EDC; palmaris longus to EPL (Riordan transfer) PL can also be hooked into APL – Brand)

– 18 months after nerve injury – plan tendon transfers! DO NOT do nerve repair.

– a 3 cm gap after injury – cable graft the nerve. DO NOT PULL ON IT TO GET IT APPOSED!

– EMG and NCS studies should be done at 3.5-4 months; some get a baseline at 2-4 weeks.

– remember to splint those with a radial nerve palsy!

– all the following could cause radial nerve entrapment: IM septum (or bands thereof), ganglia or synovial bands from radiocapitellar joint, leash of Henry, proximal arch of ECRB, arcade of Frohse. Anconeus is unlikely to cause entrapment.

– indications to explore radial nerve in humeral shaft fracture – open injury with nerve injury, secondary palsy after reduction, and Holstein-Lewis fracture with associated palsy. The only really well agreed upon one is open fracture with nerve injury. The other two are abit weak.

– for the distal 2/3 1/3 fracture (Holstein Lewis) – stick to your guns and put them in a cast!

– generally accepted rate of nerve growth is 1 mm per day – so about 30 mm per month (just over an inch per month). So for a laceration of the radial nerve 3 inches above the elbow – guess about 3 months for recovery of wrist extensors.

– for high radial nerve injury: order of re-innervation. Complicated question. The brachioradialis and ECRL obvious return first. The PIN goes through supinator and emerges (often giving off ECRB before going through supinator, or ECRB gets it from the superficial branch). As it emerges from the distal end of supinator, there are two main distributions of the PIN – one superficial to the EDC, EDMinimi, and ECU; and one that travels more deep to innervate APL, EPL, EPB, and finally most distally, Ext Indices Proprius. Notice that it looks like EPL might get innervated before EPB. Arguable. In any event, index finger extension will return before thumb retropulsion because EDC is reinnervated before EPL.

– so the order: EDC, EDMinimi, ECU (all the superficial ones); then APL, EPL, EPB, Eindicis (the deep ones)

– best treatment for humeral nonunion – ORIF

– when thinking about whether to amputate or reimplant traumatic amputations of the upper extremity (particularly hand) keep in mind that replanted digits distal to the insertion of flexor digital superficialis (into middle phalanx) do well, but replantation of single digits proximal to the FDS insertion do poorly and seldom restore hand function (because you’ll never get the PIP joint to flex!). Sharp lacerations, transcarpal, transmetacarpal, all thumb amputations should be re-implanted. Also consider replanting those with multiple digit amputations – may have to move the fingers around so that they are at the most functional place.
– “replantation of a single digit proximal to FDS seldom is indicated, particulary if it involves the index finger.” – for these, they might be better off with a ray amputation.

– distinguishing lateral

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