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9. Shoulder and Elbow MCQs

Practice Set 47 of 197

This practice set contains high-yield board review questions covering key concepts in 9. Shoulder and Elbow. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 921

Topic: 9. Shoulder and Elbow

A 74-year-old man has had worsening left shoulder pain for the past 3 years. Extensive nonsurgical management has provided only minimal relief. Examination reveals limitations in motion due to pain but good rotator cuff strength. Radiographs are shown in Figures 53a and 53b. What surgical procedure is most appropriate?

. Arthroscopic removal of osteophytes and soft-tissue release
. Soft-tissue interpositional arthroplasty
. Reverse total shoulder arthroplasty
. Hemiarthroplasty
. Total shoulder arthroplasty

Correct Answer & Explanation

. Arthroscopic removal of osteophytes and soft-tissue release

Explanation

DISCUSSION: The patient has end-stage shoulder arthritis with posterior glenoid erosion and large humeral osteophyte formation.  Since the rotator cuff is likely intact, the reverse total shoulder arthroplasty is unnecessary.  All the remaining procedures may provide symptomatic relief in appropriate patients; however, for most patients, total shoulder arthroplasty has been associated with the most predictive pain relief and functional improvements.REFERENCES: Bryant D, Litchfield R, Sandow M, et al: A comparison of pain, strength, range of motion, and functional outcomes after hemiarthroplasty and total shoulder arthroplasty in patients with osteoarthritis of the shoulder: A systemic review and meta-analysis.  J Bone Joint Surg Am 2005;87:1947-1956.Edwards TB, Kadakia NR, Boulahia A, et al: A comparison of hemiarthroplasty and total shoulder arthroplasty in the treatment of primary glenohumeral osteoarthritis: Results of a multicenter study.  J Shoulder Elbow Surg 2003;12:207-213.Gartsman GM, Roddey TS, Hammerman SM: Shoulder arthroplasty with or without resurfacing of the glenoid in patients who have osteoarthritis.  J Bone Joint Surg Am 2000;82:26-34.

Question 922

Topic: 9. Shoulder and Elbow

Figures 23a and 23b show the AP and lateral radiographs of the elbow of a 30-year-old professional pitcher. The pathology shown in these studies is most consistent with which of the following conditions?

. Insertional triceps tendinitis
. Valgus extension overload
. Medial epicondylitis
. Stress fracture of the olecranon
. Chronic olecranon bursitis

Correct Answer & Explanation

. Insertional triceps tendinitis

Explanation

DISCUSSION: The radiographs show the osteophytic build-up of the posteromedial corner of the elbow that occurs with valgus extension overload in the pitching elbow.  This is the result of excessive valgus forces during the acceleration and deceleration phases of throwing.  These forces, coupled with medial elbow stresses, cause a wedging of the olecranon into the medial wall of the olecranon fossa.  Valgus instability of the elbow may further stimulate osteophyte formation.  Repetitive impact of a spur within the olecranon fossa may cause fragmentation and eventual formation of loose bodies.REFERENCES: Azar FM, Wilk KE: Nonoperative treatment of the elbow in throwers.  Oper Tech Sports Med 1996;4:91-99.Field LD, Savoie FJ: Common elbow injuries in sport.  Sports Med 1988;26:193-205.Wilson FD, Andrews JR, Blackburn TA, et al: Valgus extension overload in the pitching elbow.  Am J Sports Med 1983;11:83-88.

Question 923

Topic: 9. Shoulder and Elbow

A 19-year-old wrestler has numbness along the radial aspect of the forearm after undergoing an open Bankart repair through an anterior deltopectoral approach. Motor weakness would be expected along with what other finding?

. Diminished elbow flexion and supination strength
. Reduced grip strength
. Weakness in shoulder abduction
. Weakness in flexion of the distal interphalangeal joint in the index finger
. Weakness of the abductor digiti minimi

Correct Answer & Explanation

. Diminished elbow flexion and supination strength

Explanation

DISCUSSION: The musculocutaneous nerve may be injured by retracting the conjoined tendon medially.  This nerve enters the coracobrachialis 5 cm distal to its origin.  Its sensory distribution is the radial forearm, and its motor supply is to the biceps and brachialis.REFERENCES: Bach BR, O’Brien SJ, Warren RF, et al: An unusual neurologic complication of the Bristow procedure.  J Bone Joint Surg Am 1988;70:458-460.McIlveen SJ, Duralde XA: Isolated nerve injuries about the shoulder, in Bigliani LU (ed): Complications of Shoulder Surgery.  Baltimore, MD, Williams and Wilkins, 1993, pp 214-239.

Question 924

Topic: Elbow & Forearm

A patient with a displaced and comminuted fracture of the radial head and neck also has pain and swelling about the ipsilateral distal radioulnar joint. Which treatment option may exacerbate the wrist disorder?

. Cross-pinning of the radius and ulna
. Open reduction and internal fixation (ORIF) of the radial head and neck fracture
. Metallic radial head implant arthroplasty
. Radial head excisionhis scenario describes a forearm-axial instability pattern, which must be recognized before pursuing treatment. Fracture or dislocation of the lateral elbow compartment (radial head/capitellum) associated with ipsilateral distal radioulnar joint derangement is a form of radioulnar dissociation commonly known as Essex-Lopresti fracture dislocation. Radial head excision sets off a chain of events, and delayed diagnosis can result in considerable morbidity following these injuries. Excision of the radial head allows proximal migration of the radius, causing potential problems at both the elbow and wrist. After such proximal migration has occurred, there is no reliable method of forearm reconstruction.There are a number of treatments for this condition. Salvage of the radial head by open reduction and internal fixation is preferable if possible. However, in cases of marked comminution, radial metallic head implant arthroplasty is an acceptable substitute. The need for soft-tissue repair or pin stabilization of the distal radioulnar joint has not been defined, although some form of forearm immobilization is necessary to allow healing of the injured interosseous membrane.

Correct Answer & Explanation

. Cross-pinning of the radius and ulna

Explanation

A 50-year-old woman has had acute weakness in her dominant hand for 6 weeks. Before noticing the onset of weakness, she experienced several weeks of vague discomfort in her shoulder and forearm, generalized fatigue, and a low-grade fever. There is no history of trauma. An examination reveals weakness of thumb and index finger distal interphalangeal (DIP) joint flexion. Electrodiagnostic testing shows fibrillations and positive sharp waves in the flexor pollicis longus and index flexor digitorum profundus muscles. The next appropriate step isA. observation.B. corticosteroid injection.C. immediate surgical decompression.D. tendon transfers.

Question 925

Topic: 9. Shoulder and Elbow

A patient presenting with scapulothoracic dissocation and ipsilateral extremity neurologic injury is most likely to have which of the following outcomes?

. Glenohumeral arthritis
. Return of 3/5 motor strength in distal extremity
. Full return of extremity sensory function only
. Flail extremity
. Death

Correct Answer & Explanation

. Glenohumeral arthritis

Explanation

DISCUSSION: Scapulothoracic dissociation is a high-energy injury resulting from massive traction injury to the shoulder girdle with disruption of the scapulothoracic articulation. The most common long term result from this injury is complete loss of motor and sensory function of the extremity (flail limb), with death in the acute or semi-acute period also common.The referenced study by Althausen et al found that outcomes from this injury were: a flail extremity in 52%, early amputation in 21%, and death in 10%.The other referenced study by Ebraheim et al found that 12/15 patients had a complete brachial plexus injury and that none recovered any function (the other 3 patients died in the acute period).

Question 926

Topic: 9. Shoulder and Elbow

Figures 1 and 2 are the MRI scans of a 57-year-old man who dislocated his left shoulder after a fall while playing tennis. On examination, he had full passive shoulder range of motion, but he was unable to actively elevate his injured shoulder. Sensation was intact to light touch over the lateral shoulder. What is the most likely etiology of his shoulder weakness?

. Axillary nerve injury
. Cervical radiculopathy involving the C6 nerve root
. Massive rotator cuff tear with loss of the transverse force couple
. Long head of the biceps tendon rupture with loss of superior stabilizing effect

Correct Answer & Explanation

. Axillary nerve injury

Explanation

This patient has a massive rotator cuff tear resulting in disruption of the transverse force couple between the subscapularis anteriorly and the infraspinatus and teres minor posteriorly. These muscles provide dynamic shoulder stability throughout active elevation, and loss of the force couple produces a pathologic increase in translation of the humeral head and decreased active abduction. Active shoulder elevation <90 degrees in the presence of full passive motion is termed pseudoparalysis. The most common neurologic deficit after shoulder dislocation is isolated injury to the axillary nerve. This patient's sensory examination suggests that the axillary nerve is intact. Cervical radiculopathy is less common after shoulder dislocation but has been reported. Conflicting evidence exists regarding the contribution of the long head of the biceps tendon to glenohumeral stability. One study reported minimal electromyographic activity in the biceps during ten basic shoulder motions.

Question 927

Topic: 9. Shoulder and Elbow

A 55-year-old man who underwent total shoulder arthroplasty 10 years ago recently reports an increase in shoulder pain. Laboratory studies consisting of a white blood cell count, erythrocyte sedimentation rate, and C-reactive protein are all negative, as is joint aspiration. Radiographs are shown in Figures 95a and 95b. If all intraoperative frozen sections are negative, what is the appropriate treatment during revision surgery to provide pain relief and improved function? Review Topic

. Placement of antibiotic spacer
. Removal of the glenoid, and possible bone grafting
. Conversion to reverse shoulder arthroplasty
. Referral to pain management
. Shoulder arthrodesis

Correct Answer & Explanation

. Placement of antibiotic spacer

Explanation

The radiographs reveal a loose glenoid in the setting of no infection. Glenoid removal may give this patient the best chance of improved function and pain relief if sufficient bone stock remains. Bone grafting of defects may allow future glenoid implantation. Conversion to reverse shoulder arthroplasty would be a salvage procedure in this younger patient. Shoulder arthrodesis would be difficult and unpredictable after shoulder arthroplasty.

Question 928

Topic: 9. Shoulder and Elbow

An 19-year-old male presents to the emergency room following an motor vehicle accident as an unrestrained driver. Examination reveals unilateral jugular vein engorgement. Chest and special view radiographs are seen in Figures A and B respectively. Following CT scan of the chest, the next step in management is Review Topic

. Nonsurgical management and follow-up CT scan in 6 weeks
. Closed reduction in the emergency room under sedation
. Closed reduction in the operating room under general anesthesia with thoracic surgery on standby, followed by figure-of-8 clavicle strap immobilization for 4 weeks
. Closed reduction in the operating room under general anesthesia with thoracic surgery on standby, followed by compression plating
. Open reduction in the operating room under general anesthesia, followed by transarticular pinning with K-wires

Correct Answer & Explanation

. Nonsurgical management and follow-up CT scan in 6 weeks

Explanation

This patient has a right posterior sternoclavicular (SC) dislocation. Management involves closed reduction and bracing. Closed reduction should be performed with a thoracic surgeon available in the event of mediastinal involvement.The SC joint can dislocate anteriorly or posteriorly. Posterior dislocations are first treated with closed reduction. If closed reduction fails, open reduction is indicated. Early complications of posterior SC dislocation include pneumothorax, laceration/erosion/occlusion of great vessels, esophageal rupture and brachial plexus compression. Late complications include tracheoesophageal fistula, stridor and dysphagia.Groh et al. reviewed traumatic SC injuries. Reduction maneuvers in posterior SC dislocation include: (1) traction on the arm and slowly bringing it into extension, (2) traction with the arm in adduction and posterior pressure applied to the shoulder, and(3) pulling anteriorly on a towel clip encircling the medial clavicle. Chronic instability after posterior SC dislocations can be managed with figure-of-8 semitendinosus graft or medial clavicle resection and reattachment of the clavicle to the first rib with dacron tape.Glass et al. performed a systematic review on SC dislocations. They found mediastinal compression occurred 30% of the time with posterior dislocations.Figures A and B are radiographs demonstrating asymmetry of the SC joints, characteristic of a right posterior SC dislocation (Figure B is not a serendipity view). Illustration A demonstrates how in POSTERIOR dislocation, the clavicle appears INFERIOR, and in ANTERIOR dislocation, the clavicle appears SUPERIOR on a serendipity view radiograph respectively. Illustration B shows the imaging technique for a serendipity view radiograph. Illustration C is a reconstructed CT image of the patient showing left posterior SC dislocation.Incorrect Answers:

Question 929

Topic: 9. Shoulder and Elbow

Which of the following positions of immobilization has been shown to best approximate the anterior labrum against the glenoid rim following anterior dislocation of the shoulder?

. Abduction and external rotation
. Abduction and internal rotation
. Adduction and external rotation
. Adduction and internal rotation
. Extension

Correct Answer & Explanation

. Adduction and external rotation

Explanation

DISCUSSION: Following anterior dislocation of the shoulder, the affected arm is typically placed in a sling with the shoulder in adduction and internal rotation.  A recent study has shown that placement in this position actually results in laxity of the anterior supporting structures of the shoulder, allowing the postinjury hemarthrosis to push the labrum and capsular ligaments away from the anterior glenoid rim.  Thus, immobilization in this position may actually impede healing of these structures.  Alternatively, resting the arm in a position of adduction and external rotation allows the anterior supporting structures to abut against the anterior glenoid rim by forcing the hemarthrosis posteriorly.  Placing the arm in this position following anterior dislocation is believed to allow for better healing of the anterior labrum and ligaments.REFERENCE: Itoi E, Sashi R, Minagawa H, et al: Position of immobilization after dislocation of the glenohumeral joint: A study with use of magnetic resonance imaging.  J Bone Joint Surg Am 2002;84:873-874.

Question 930

Topic: Elbow & Forearm

At what age does the lateral epicondyle normally ossify in males?

. 2 to 4 years
. 5 to 6 years
. 7 to 8 years
. 9 to 11 years
. 12 to 14 years

Correct Answer & Explanation

. 2 to 4 years

Explanation

The lateral epicondylar epiphysis is the last to ossify in the elbow at age 12 to 14 years in males. The first secondary ossification center to ossify is the capitellum, which ossifies during the first 6 months of life. Next is the radial head, ossifying between age 3 and 6 years. The medial epicondyle appears between 5 and 7 years; the trochlea and olecranon at 8 and 10 years, respectively. In females, the appearance of ossification centers is about a year earlier than males.

Question 931

Topic: 9. Shoulder and Elbow

After the athlete undergoes the appropriate treatment of the postsurgical complication and recovers without further incident, which muscle most likely will be last to experience return of function?

. Extensor indicis proprius (EIP)
. Extensor digiti quinti (EDQ)
. Extensor digitorum communis (EDC)
. Extensor carpi ulnaris (ECU)

Correct Answer & Explanation

. Extensor indicis proprius (EIP)

Explanation

DISCUSSIONThis patient sustained an eccentric contracture (muscle lengthening while contracting) of his biceps muscle while trying to stop a defender from getting around him. This in turn caused failure of the distal biceps tendon, as evidenced by pain in the antecubital fossa, lack of elbow supination strength, and his positive biceps active test finding (supination/pronation of the forearm showing no motion of the biceps muscle belly). Eccentric contractors have the highestpotential for building strength but also are at highest risk for injury. Concentric (muscle shortening with contraction), isometric (no change in muscle length with contracture), and isokinetic (constant velocity of muscle contraction with a variable force) do not describe the mechanism detailed.The loss of distal biceps attachment will result in loss of elbow supination strength in flexion (the biceps is the only supinator to cross the elbow) while still retaining elbow flexion (albeit weakened) because of the other elbow flexors (brachioradialis and brachialis). Consequently, treatment should be anatomic repair of the distal biceps insertion, which can be performed with a 2-incision or 1-incision technique. Although all of the listed complications have been reported with these techniques, LABC neuropraxia is by far the most common. Radiographs show that this athlete’s injury was repaired using a 1-incision technique with a cortical fixation device and a radial bone tunnel. This technique has gained favor because of its decreased incidence of heterotopic ossification and radioulnar synostosis compared to the 2-incision technique. The most troubling complication for most surgeons is the development of a PIN palsy, which this patient clearly demonstrates in addition to the more common LABCN upon postsurgical examination. Because the LABC nerve injury is typically a neuropraxia from retraction, a period of observation is indicated. PIN injury can result from excessive traction during surgical exposure or from entrapment by the fixation button.Considering the anatomy of the PIN, successful recovery of the nerve typically progresses based on the distance from the origin of the nerve to the muscle indicated. The EIP is the most distal muscle innervated and can be expected to recover last. First to return would be the EDC followed by the ECU, EDQ, and, finally, the EIP.RESPONSES FOR QUESTIONS 26 THROUGH 27Anterior tibial arteryPosterior tibial arterySuperficial peroneal nerveDeep peroneal nerveMatch the neurovascular structure at risk (listed above) with the compartment undergoing fasciotomy (listed below).

Question 932

Topic: 9. Shoulder and Elbow

Figure 33 shows the CT scan of a 40-year-old man who injured his left shoulder while skiing. What structure is attached to the bony fragment?

. Superior glenohumeral ligament
. Anterior band of the inferior glenohumeral ligament
. Middle glenohumeral ligament
. Subscapularis tendon
. Long head of the biceps tendon

Correct Answer & Explanation

. Superior glenohumeral ligament

Explanation

DISCUSSION: The scan reveals a bony Bankart lesion.  The anterior band of the inferior glenohumeral ligament is the major restraint to anterior translation of the humeral head and is usually injured with anterior shoulder dislocations.  It inserts onto the glenoid labrum at the anteroinferior aspect of the glenoid rim.  The labrum most frequently avulses from the glenoid (Bankart lesion), but occasionally the bony attachment is avulsed.REFERENCES: O’Brien SJ, Neves MC, Arnoczky SP, et al: The anatomy and histology of the inferior glenohumeral ligament complex of the shoulder.  Am J Sports Med 1990;18:449-456.Warner JP: The gross anatomy of the joint surfaces, ligaments, labrum and capsule, in Matsen FA, Fu FF, Hawkins RJ (eds): The Shoulder: A Balance of Mobility and Stability.  Rosemont, IL, American Academy of Orthopaedic Surgeons, 1992, pp 7-28.

Question 933

Topic: 9. Shoulder and Elbow

A 55-year-old woman with a 15-year history of systemic lupus erythematosus has had left shoulder pain for the past 3 months. She reports that the pain has grown progressively worse over the past few months, and her shoulder function is severely limited. She is presently being treated with azathioprine and has used corticosteroids in the past. AP and axillary radiographs are shown in Figures 19a and 19b, and MRI scans are shown in Figures 19c and 19d. Which of the following forms of management will yield the most predictable pain relief and return of shoulder function?

. Stretching exercises with a physical therapist
. Arthroscopic debridement
. Core decompression of the humeral head
. Humeral hemiarthroplasty
. Resection of the proximal humerus

Correct Answer & Explanation

. Stretching exercises with a physical therapist

Explanation

DISCUSSION: Prosthetic shoulder arthroplasty has been shown to provide predictable results for treating stage III and stage IV osteonecrosis of the humeral head.  The decision to resurface the glenoid (total shoulder arthroplasty versus humeral hemiarthroplasty) usually is made based on the radiographic and intraoperative appearance of the glenoid.  Core decompression of the humeral head has been reported to be effective for earlier stages (pre collapse) but would not be appropriate for a patient with stage IV disease.REFERENCES: Hattrup SJ, Cofield RH: Osteonecrosis of the humeral head: Results of replacement.  J Shoulder Elbow Surg 2000;9:177-182.L’Insalata JC, Pagnani MJ, Warren RF, et al: Humeral head osteonecrosis: Clinical course and radiographic predictors of outcome.  J Shoulder Elbow Surg 1996;5:355-361.Cruess RL: Steroid-induced avascular necrosis of the head of the humerus: Natural history and management.  J Bone Joint Surg Br 1976;58:313-317.

Question 934

Topic: 9. Shoulder and Elbow

What is the most consistent finding regarding glenohumeral kinematics in patients with symptomatic tears of the rotator cuff?

. No superior translation during abduction
. Retention of ball-and-socket kinematics with more than 30 degrees of abduction
. Loss of ball-and-socket kinematics with less than 30 degrees of abduction
. Superior translation of the humeral head with more than 30 degrees of abduction
. Superior translation of the humeral head with external rotation

Correct Answer & Explanation

. Superior translation of the humeral head with more than 30 degrees of abduction

Explanation

DISCUSSION: Normal glenohumeral kinematics are represented by ball-and-socket modeling when the rotator cuff is intact.  This is true for motion that involves more than 30 degrees of abduction.  In patients with shoulder pain and symptomatic rotator cuff tears, superior translation occurs with abduction beyond 30 degrees.  This is quite evident in massive tears but is seen consistently to a lesser degree with smaller tears.REFERENCES: Yamaguchi K, Sher JS, Anderson WK, et al: Glenohumeral motion in patients with rotator cuff tears: A comparison of asymptomatic and symptomatic shoulders.  J Shoulder Elbow Surg 2000;9:6-11.Poppen NK, Walker PS: Normal and abnormal motion of the shoulder.  J Bone Joint Surg Am 1976;58:195-201.

Question 935

Topic: 9. Shoulder and Elbow

The essential lesion in recurrent or posterior instability following simple dislocation of the elbow typically involves which of the following structures?

. Medial collateral ligament
. Lateral ulnar collateral ligament
. Coracohumeral ligament
. Anterior joint capsule
. Posterior joint capsule

Correct Answer & Explanation

. Lateral ulnar collateral ligament

Explanation

The lateral ulnar collateral ligament is the essential lesion in recurrent or persistent instability following simple dislocations of the elbow. Simple elbow dislocations are usually stable and may be managed by a short period of immobilization followed by early range of motion. Treatment of dislocations resulting in persistent instability frequently involves focusing on the lateral ulnar collateral ligament. The medial collateral ligament is repaired only if treatment of associated fractures and lateral collateral ligament injury does not restore stability.

Question 936

Topic: 9. Shoulder and Elbow

A right-handed 14-year-old pitcher has had a 3-month history of shoulder pain while pitching. Examination reveals full range of motion, a mildly positive impingement sign, pain with rotational movement, and no instability. Plain AP radiographs of both shoulders are shown in Figures 25a and 25b. Management should consist of

. referral to a pitching coach to improve throwing mechanics.
. a weight-training program that concentrates on rotator cuff strengthening.
. rest until symptoms have resolved, followed by a gradual return to pitching.
. a metabolic work-up.
. cessation of pitching until the physis is closed.

Correct Answer & Explanation

. rest until symptoms have resolved, followed by a gradual return to pitching.

Explanation

DISCUSSION: The patient has the classic signs of Little Leaguer’s shoulder, with findings that include pain localized to the proximal humerus during the act of throwing and radiographic evidence of widening of the proximal humeral physis.  Examination usually reveals tenderness to palpation over the proximal humerus, but the presence of any swelling, weakness, atrophy, or loss of motion is unlikely.  The treatment of choice is rest from throwing for at least 3 months, followed by a gradual return to pitching once the shoulder is asymptomatic.REFERENCES: Carson WG Jr, Gasser SI: Little Leaguer’s shoulder: A report of 23 cases.  Am J Sports Med 1998;26:575-580.Barnett LS:  Little League shoulder syndrome: Proximal humeral epiphyseolysis in adolescent baseball pitchers.  A case report.  J Bone Joint Surg Am 1985;67:495-496.

Question 937

Topic: 9. Shoulder and Elbow

A 74-year-old woman with rheumatoid arthritis reports shoulder pain that has failed to respond to nonsurgical management. AP and axillary radiographs are shown in Figures 23a and 23b. Examination reveals active forward elevation to 120 degrees and external rotation to 30 degrees. What treatment option results in the most predictable pain relief and function?

. Hemiarthroplasty
. Arthroscopic debridement
. Total shoulder arthroplasty with a cemented all-polyethelene glenoid component
. Reverse total shoulder arthroplasty
. Total shoulder arthroplasty with a metal-backed glenoid component

Correct Answer & Explanation

. Total shoulder arthroplasty with a cemented all-polyethelene glenoid component

Explanation

DISCUSSION: Most studies have shown that total shoulder arthroplasties yield better pain relief and improved forward elevation when compared to hemiarthroplasty in patients with rheumatoid arthritis.  Although rotator cuff tears are more common in this patient population, this patient has good forward elevation and no significant superior migration of the humeral head; therefore, a reverse arthroplasty is not indicated.  The arthritis is too advanced in this patient to consider arthroscopy, but in less advanced cases it can improve range of motion and decrease pain.  Metal-backed glenoid components have shown higher rates of loosening.REFERENCES: Collin DN, Harryman DT II, Wirth MA: Shoulder arthroplasty for the treatment of inflammatory arthritis.  J Bone Joint Surg Am 2004;86:2489-2496.Baumgarten KM, Lashgari CM, Yamaguchi K: Glenoid resurfacing in shoulder arthroplasty: Indications and contraindications.  Instr Course Lect 2004;53:3-11.Martin SD, Zurakowski D, Thornhill TS: Uncemented glenoid component in total shoulder arthroplasty: Survivorship and outcomes.  J Bone Joint Surg Am 2005;87:1284-1292.

Question 938

Topic: Elbow & Forearm

What is the best way to determine whether a radial head implant is too thick intraoperatively?

. Visually assess the radiocapitellar joint.
. Visually assess widening of the lateral ulnohumeral joint.
. Assess widening of the radiocapitellar joint on an AP radiograph.
. Assess the elbow for concentric reduction on a lateral radiograph.
. Assess widening of the medial ulnohumeral joint on an AP radiograph.

Correct Answer & Explanation

. Assess widening of the medial ulnohumeral joint on an AP radiograph.

Explanation

Widening of the medial ulnohumeral joint on an AP radiograph is only visible after overlengthening of the radial head by 6 mm or more. At least in this cadaver study, the most sensitive method was to visually assess the lateral aspect of the ulnohumeral joint with the radial head resected and then with the trial radial head in place. This method allows detection of any overlengthening.

Question 939

Topic: 9. Shoulder and Elbow

A 75-year-old man sustains an anterior dislocation of his reverse total shoulder arthroplasty. What activity places the arm in the position most commonly associated with reverse total shoulder dislocation?

. Scratching the opposite shoulder
. Pushing off ipsilateral chair armrest while standing up
. Tying shoelaces on the contralateral foot
. Reaching up to comb hair

Correct Answer & Explanation

. Pushing off ipsilateral chair armrest while standing up

Explanation

Proper soft-tissue tension is critical to prevent instability of a reverse total shoulder implanted with the deltopectoral approach; dislocation of the prosthesis is exceedingly rare if the superior approach is employed. The arm position implicated in reverse total shoulder instability is extension, adduction, and internal rotation,such as pushing out of a chair. The other positions described do not involve extension of the shoulder.

Question 940

Topic: 9. Shoulder and Elbow

A 17-year-old girl develops chronic posterolateral rotatory instability (PLRI) of the elbow following closed treatment of an elbow dislocation. Advanced imaging reveals incompetence of the lateral collateral ligament complex, and ligament reconstruction is planned. Examination under anesthesia is performed with the forearm in maximal supination and valgus force applied to the elbow, demonstrated in Video 1. As the elbow is brought through a range of motion assessment, the radial head is

. dislocating posteriorly in extension and reducing in flexion.
. dislocating posteriorly in flexion and reducing in extension.
. dislocating anteriorly in extension and reducing in flexion.
. dislocating anteriorly in flexion and reducing in extension.PLRI of the elbow is the most common form of chronic elbow instability. The mechanism occurs following a fall onto an outstretched hand, where a valgus force is applied to the elbow and the forearm rotates into progressive supination. This allows the radial head to translate posterior to the capitellum, with progressive injury from lateral to medial sides of the elbow. The pivot shift test is a useful examination maneuver to confirm the presence of PLRI. With the forearm in maximal supination and valgus stress applied to the elbow, the radial head is forced posterior to the capitellum as the elbow is brought into progressive extension, revealing a dimple on the lateral aspect of the elbow. This typically occurs at roughly 30° of flexion. As the elbow is flexed, the radial head reduces.

Correct Answer & Explanation

. dislocating posteriorly in extension and reducing in flexion.

Explanation

Figure 1 is the MRI of a 45-year-old woman with a medical history significant for rheumatoid arthritis who returns to your office with persistent right elbow pain. Her rheumatologist has maximized her disease-modifying anti-rheumatoid drug regimen. She complains of diffuse joint pain and swelling. On examination, she has a pronounced joint effusion, elbow flexion arc of 45°, and crepitus with forearm rotation. Her elbow radiograph reveals preservation of her joint space. What is the most appropriate surgical treatment at this time?

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