Essentials of Orthopedic Surgery, third edition / 14-Answers to Questions

7-8. Answer: d

The extensor hallucis longus is innervated by L5; weakness of this muscle would be evidence of an L5 radiculopathy.

7-9. Answer: c

Spondylolysis is believed to be a stress or fatigue fracture of the pars interarticularis occurring because of repetitive shear stresses from repetitive hyperextension in individuals with a hereditary predisposition. It occurs most commonly at L5, is more common in boys than in girls and in athletes, particularly gymnasts.

7-10. Answer: d

Urinary retention results from lower motor neuron bladder dysfunction seen in cauda equina compression (CEC) syndrome. Patients with CEC syndrome may also present with severe back pain, saddle anesthesia, pain down the back of lower extremities, or even foot drop, but the most typical and most important manifestation is bladder dysfunction.

Chapter 8

8-1. Answer: c

The scapula and posterior thorax articulate through a number of bursae, but there is no articular surface.

8-2. Answer: b

The anterior band of the inferior glenohumeral ligament complex is the main stabilizer of the humeral head when it is abducted and externally rotated.

8-3. Answer: a

Central erosion of the glenoid is more common in inflammatory arthropathy. In glenohumeral osteoarthritis, posterior glenoid wear is more common.

8-4. Answer: e

The spinal accessory nerve is the 11th cranial nerve and innervates the trapezius muscle.

8-5. Answer: c

The deltoid muscle is critical for elevation and abduction of the shoulder girdle, but it is not part of the rotator cuff.

8-6. Answer: a

Although all the above regions can produce referred pain into the shoulder, the cervical spine is the most common origin of shoulder pain that does

516 Answers to Questions

not emanate from the shoulder girdle. Most patients with cervical spine pathology presenting as shoulder pain localize the pain to the trapezial and posterior scapular regions.

8-7. Answer: d

Total shoulder arthroplasty and humeral head replacement are the most common surgical procedures used to treat end-stage osteoarthritis of the glenohumeral joint. Arthroscopic debridement of the glenohumeral joint is also a reasonable alternative in some patients with osteoarthritis of the glenohumeral joint. Glenohumeral fusion is an option for the treatment of osteoarthritis but is not generally recommended because of the severe restriction in motion that occurs.

8-8. Answer: e

The MRI scan is currently the gold standard for noninvasive evaluation of the rotator cuff tendons.

8-9. Answer: a

Adhesive capsulitis is initially treated with physical therapy for capsular stretching and NSAIDs. Corticosteroid injections into the glenohumeral joint are also helpful for pain relief. Arthroscopic adhesiolysis and manipulation under anesthesia are both options for patients who fail nonoperative treatment.

8-10. Answer: e

Most rotator cuff tears are degenerative in nature. The presence of rotator cuff tears has been documented by MRI scans in normal patients, and, in this asymptomatic population, the incidence of rotator cuff tears increases with the age of the patient.

Chapter 9

9-1. Answer: c

The thenar musculature is supplied by the recurrent motor branch of the median nerve, so it is never involved in isolated cubital tunnel syndrome. It is a late finding in carpal tunnel syndrome. The other signs are all common in cubital tunnel syndrome.

9-2. Answer: e

Treatment of lateral epicondylitis should focus on conservative management with rest, activity modification, modalities, bracing, physical therapy, and injections. When all else fails, arthroscopic and open surgical options are available.

9-3. Answer: d

The musculocutaneous nerve innervates the coracobrachialis, the biceps brachii, and the brachialis.

9-4. Answer: b

This term has been coined to describe the pathologic tissue in lateral epicondylitis based on its microscopic appearance. It has little, if any, inflammatory component.

9-5. Answer: d

For fractures around the elbow, it is critical to obtain good alignment and begin early motion. The only way to achieve this for the fracture described is through rigid internal fixation.

9-6. Answer: c

The brachioradialis is a powerful elbow flexor when the forearm is pronated.

9-7. Answer: a

The arcade of Frohse is a ligamentous band between the two heads of the supinator. It can compress the posterior interosseous branch of the radial nerve but not the ulnar nerve.

9-8. Answer: e

The above-mentioned muscles encompass the motor innervation of the anterior interosseous branch of the median nerve.

9-9. Answer: At this time, arthroscopic or endoscopic techniques are not indicated for median nerve release at the elbow. All the other procedures have been described by authors with reasonably good results when done arthroscopically.

9-10. Answer: e

MRI can be helpful for all the conditions listed.

Chapter 10

10-1. Answer: d

Aside from skin cancer, such as squamous cell carcinoma, malignancies in the hand are extremely rare. The most common ones are epithelioid sarcoma, synovial cell sarcoma, and malignant fibrous histiocytoma.

518 Answers to Questions

Isolated metastatic disease to the bones of the hand are particularly uncommon conditions.

10-2. Answer: e

Although most patients who develop carpal tunnel syndrome have no known underlying causative factor, several medical conditions can contribute to the onset of this disease. All of the diagnoses mentioned as well as other conditions such as amyloidosis or antiinflammatory arthropathies can contribute to compression of the median nerve at the wrist.

10-3. Answer: b

When a patient presents with a radial aplasia such as a radial clubhand or thumb deficiency, evaluation by the appropriate pediatric subspecialist should be performed for visceral anomalies: these includes vertebral anomalies, imperforate anus, tracheoesophageal problems, thrombocytopenia, and other potentially life-threatening problems. It is uncommon for the other anomalies mentioned to have significant visceral involvement.

10-4. Answer: a

Osteoarthritis of the hand and wrist is a very common condition that markedly diminishes a patient’s hand function. Commonly involved joints include the thumb CMC joint, the scaphotrapeziotrapezoid joint, the PIP joints, and the DIP joints. The MP joints of the index through small finger are most commonly spared until very late in the disease process.

10-5. Answer: d

Forced ulnar deviation of the thumb and wrist causing severe pain over the

first dorsal compartment is a positive Finkelstein’s test. It is indicative of de Quervain’s tenosynovitis. One of the chief conditions in the differential diagnosis is thumb CMC arthritis, which is further differentiated by a CMC grind test.

10-6. Answer: c

The small finger receives nearly all its sensory function from the ulnar nerve and, as such, carpal tunnel syndrome rarely causes isolated small finger numbness. Patients often have a sensation of global numbness and until specifically tested do not realize their small finger is spared.

10-7. Answer: d

Open hand wounds should almost never be explored on initial evaluation. They should be covered with a sterile dressing, and a careful documenta-

tion of nerve, tendon, and vascular function distal to the injury should be obtained before applying an anesthetic block. After this evaluation, definitive management can be performed either in the emergency room, if appropriate, or in the operating room, if necessary.

10-8. Answer: e

Human bite wounds are fairly common injuries usually caused by the patient punching another person in the mouth. Many different bacteria can be involved. Staphylococus aureus is the most common infectious agent in this situation, but one must cover Eikenella corrodens as well, because it is a common bacterium in the human mouth.

10-9. Answer: e

Scaphoid fractures, although the most common fractures of the carpal bones, are often difficult to diagnose and treat because of the poor blood supply. Nonunion and osteonecrosis occur at relatively high rates. One should maintain a high index of suspicion when patients present with radial-sided wrist pain and anatomic snuff box tenderness, even if initial X-rays are negative.

10-10. Answer: c

Bone destruction is a very uncommon finding in suppurative flexor tenosynovitis. The remaining four options constitute Kanavel’s four signs, which are pathognomonic for the disease process.

10-11. Answer: d

Gamekeeper’s thumb is an ulnar collateral ligament rupture of the thumb MP joint. It can be associated with a Stener lesion, in which the ruptured ligament button-holes into the adductor aponeurosis and becomes incarcerated there.

Chapter 11

11-1. Answer: d

The artery of the ligamentum teres, a branch of the obturator artery, only supplies approximately 10% to 20% of the blood supply to the femoral head. The majority of the blood supply comes from the small retinacular vessels that run in the synovial space. They are supplied by the medial and lateral femoral circumflex vessels from the profunda femoris artery. The internal iliac artery and the superior gluteal artery do not contribute to the femoral head.

520 Answers to Questions

11-2. Answer: c

The primary internal rotator of the hip is the gluteus medius muscle. The anterior one-third of that muscle runs from the iliac wing to the anterior greater trochanter. The iliopsoas and piriformis are external rotators. The rectus femoris and iliopsoas are hip flexors. The gluteus maximus is a hip extensor.

11-3. Answer: b

Rheumatoid arthritis is an inflammatory arthritis. Inflammatory arthritis results from an autoimmune attack of the articular cartilage, which results in involvement in the entire joint. Therefore, there is no preserved cartilage to rotate into a weight-bearing area. Inflammatory arthritis is a contraindication to osteotomy. The other conditions listed are indications for osteotomy.

11-4. Answer: d

The rate of deep venous thrombosis (DVT) is between 10% and 20%. DVT is the most common complication after hip replacement. The rate of loosening is approximately 0.5% to 1% per year, of perioperative fracture is approximately 1%, and of infection is approximately 0.1% to 0.4%. The rate of dislocation after total hip replacement is between 1% and 5%.

11-5 Answer: e

All the listed factors alone or in combination can be responsible for the dislocation of a total hip replacement.

11-6. Answer: d

Patients at high risk for the formation of heterotopic ossification after total hip replacement can be treated with 700 to 800 cGy radiation therapy to reduce the risk of bone formation; this is usually administered as a single dose of therapy. The other treatment that has been shown to be successful is the use of NSAI medications.

11-7. Answer: b

A fracture of the femoral neck can result in disruption of the small retinacular vessels that lie in the synovial space; this will destroy the blood supply of the femoral head and result in avascular necrosis even if the fracture is repaired.

11-8. Answer: a

The anterior approach to the hip detaches a portion of the gluteus medius from the greater trochanter; this can result in a limp postoperatively if it

is not properly repaired. The tensor fascia lata is displaced anteriorly and does not attach to the trochanter. The quadratus femoris, piriformis, and gluteus maximus all are posterior.

11-9. Answer: c

Deep periprosthetic infection is a devastating complication that requires at least two surgeries and 6 to 8 weeks of intravenous antibiotics to treat.

It will occur more frequently in patients taking oral corticosteroids. Antibiotics alone either orally or intravenously cannot be used to treat periprosthetic sepsis.

11-10. Answer: d

A coxalgic gait pattern results from a decreased stance phase and an abductor lurch. An antalgic or painful gait pattern is any gait with a reduced stance phase. The stance phase is reduced to decrease the time standing on a painful lower extremity. An abductor lurch results from weakened hip abductors. To compensate for the weakened abductors, the patient shifts the upper body over the affected hip to reduce to stress on the hip abductors, resulting in a lurch. Combining the two patterns results in a coxalgic gait pattern.

Chapter 12

12-1. Answer: a

Posterior translation of the tibia relative to the femur is primarily restricted by the posterior cruciate ligament. The quadriceps and the extensor mechanism are secondary restraints to posterior translation. The anterior translation of the knee is resisted by the anterior cruciate ligament. Varus and valgus opening are resisted by the lateral and medial collateral ligaments, respectively.

12-2. Answer: a

In all modern knee replacements, the anterior cruciate ligament is removed. The function of the ligament is replaced by the design of the implants for the arthroplasty. The posterior cruciate ligament can either be retained or taken for the arthroplasty. The implant design varies depending upon what is done with the ligament. The medial, lateral, and patellar ligaments are necessary for the proper functioning of a total knee replacement.

12-3. Answer: d

The most common complication after total knee replacement is infection. The rate of deep venous thrombosis is approximately 10%. The second

522 Answers to Questions

most frequent complication after total knee replacement is stiffness, occurring in approximately 2% of cases. The other listed complications occur at a rate of less than 0.5%.

12-4. Answer: b

Osteotomy of the knee is indicated for patients with osteoarthritis of the knee isolated to one part of the knee, that is, either the medial, lateral, or patellofemoral compartment. Valgus osteoarthritis is best treated with a varus osteotomy to correct the valgus deformity; this can be done on either the tibia or femur. Osteotomy is contraindicated in rheumatoid arthritis and in tricompartmental osteoarthritis. Patellofemoral osteoarthritis cannot be treated with either a varus or valgus osteotomy.

12-5. Answer: b

This patient is developing an early wound complication after total knee replacement. This is an urgent situation. If it is not rapidly addressed, the patient will quickly develop a deep wound infection, which can require multiple surgeries to correct and long courses of antibiotic. Infection is the most feared complication after a joint replacement arthroplasty.

12-6. Answer: e

If a knee replacement becomes loose before 5 years after implantation, it should be considered infected until proven otherwise. Stiffness and neurovascular injury will occur early after the surgery. Fracture can occur at any time after the surgery and is associated with osteoporosis. Osteoporosis is not associated with loosening after total knee replacement.

12-7. Answer: d

Resection is a salvage procedure used to treat a multiply operated knee that has failed. This procedure is also best reserved for minimally active sedentary patients. Patients with chronic instability and arthritis are best treated by reconstruction or replacement.

12-8. Answer: c

The patient with osteoarthritis may experience more pain after the procedure than they had before. The results of arthroscopy for osteoarthritis are not highly successful and do not have a good long-term success. The ability of arthroscopy to delay total knee arthroplasty is unproven, and it is not necessary to do it before total knee replacement.

12-9. Answer: e

All the measures are important in the nonoperative management of knee osteoarthritis. There is never a rush to surgery. All patients should be tried in a good conscientious course of conservative management before total knee replacement.

12-10. Answer: e

All the listed symptoms are commonly seen in patients with chondromalacia of the patella. Pain with prolonged sitting is also referred to as movie sign.

Chapter 13

13-1. Answer: b

The distal fibula lies laterally and slightly posterior to the tibia and is held there by the inferior tibiofibular ligaments. The lateral surface of the distal tibia has a sulcus to accommodate the adjacent fibula, forming the distal tibiofibular joint.

13-2. Answer: d

The talar dome is the superior portion of the talar body that articulates with the mortise of the tibia and fibula. The dome is wider anteriorly, which allows for stability in the mortise during dorsification.

13-3. Answer: e

The foot is composed of 7 tarsals, 5 metatarsals, and 14 phalanges. Three anatomic groupings are defined for descriptive purposes: the hindfoot, the midfoot, and the forefoot (see Figure 13-3). In the hindfoot lies the largest bone in the foot, the calcaneus.

13-4. Answer: c

Ligaments of the ankle syndesmosis include the anterior tibiofibular, posterior tibiofibular, and inerosseous ligaments.

13-5. Answer: e

The tibial and common peroneal nerves are terminal branches of the sciatic nerve, which arises from the lumbosacral plexus. The common peroneal nerve from L5 branches into the superficial peroneal nerve and deep peroneal nerve, which terminally supply sensation to the dorsal foot and first web space, respectively. The tibial nerve, a branch of S1, travels through the popliteal fossa into the deep posterior compartment. The sural

524 Answers to Questions

nerve is a sensory branch of the tibial nerve and provides sensation to the posterolateral hindfoot and lateral border of the foot.

13-6. Answer: e

Radiographic studies of the foot and ankle require weight-bearing X-rays when possible. Important views involve the anteroposterior (AP), lateral, and oblique views of the foot, and AP, lateral, and mortise views of the ankle.

13-7. Answer: c

Pilon fractures involve the intraarticular fractures of the tibial metaphysis, which extend to the weight-bearing portion of the tibia; a is a Lisfranc fracture-dislocation, and e is also known as a Jones fracture.

13-8. Answer: e

All the above answers define a hallux valgus, or bunion, deformity. Answers a, c, and d may be observed clinically. Answers a, b, and c may be seen radiographically.

13-9. Answer: b

Because the insole of a sneaker can be colonized with the Pseudomonas organism, care should be taken to treat the patient with an infection from a puncture wound for this organism.

13-10. Answer: c

Overuse of the posterior tibial tendon causes conditions that range from mild tendonitis to complete rupture and asymmetrical flatfoot deformity.

As the tendon continues to deteriorate and becomes incompetent, a progressive asymmetrical flatfoot deformity develops with lateral hindfoot impingement.