7. Hand and Wrist MCQs

DISCUSSION: The majority of mallet fractures can be treated nonsurgically with a distal interphalangeal joint extension splint. Excellent results can be obtained in most patients with splinting alone. The fragment size, amount of displacement, and degree of articular incongruity usually do not affect final outcome, as long as the joint is reduced. Surgical fixation takes on several forms but is fraught with complications including skin/wound problems, loss of fixation, nonunion, and stiffness of the distal interphalangeal joint. Volar subluxation of the distal phalanx remains the primary indication for surgical treatment. REFERENCES: Green DP, Butler TE Jr: Fractures and dislocations in the hand, in Rockwood CA, Green DP, Bucholz RW, Heckman JD (eds): Rockwood and Green’s Fractures in Adults, ed 4. Philadelphia, PA, Lippincott-Raven, 1996, pp 621-623. Light TR (ed): Hand Surgery Update 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 19-28.

DISCUSSION: The flexor sheaths are in continuity with the deep spaces of the hand. The flexor sheaths of the thumb and little finger communicate with the radial and ulnar bursae, respectively, and these two bursae commonly communicate. The central digits do not communicate as readily with deep spaces of the hand but if flexor tendon sheath infection of the index, long, and ring fingers is neglected, the potential exists for rupture into the deep midpalmar spaces. REFERENCES: Peimer CA (ed): Surgery of the Hand and Upper Extremity: Acute and Chronic Sepsis. New York, NY, McGraw Hill, 1996, pp 1735-1741. Trumble TE (ed): Hand Surgery Update 3: Hand, Elbow and Shoulder. Rosemont, IL, American Society for Surgery of the Hand, 2003, pp 445-446.

The radiograph reveals oblique fractures of the third and fourth metacarpals. The rotational component of the fracture displacement is well visualized on the clinical photograph, which shows scissoring of the middle finger over the ring finger. The fracture obliquity results in rotational deformity that cannot be adequately maintained and held by closed treatment. The treatment of choice is open reduction and internal fixation.

DISCUSSION: A rare complication of non-displaced or minimally displaced fractures of the distal radius treated with a cast is a delayed rupture of the extensor pollicis longus (EPL) tendon. The EPL is the primary extensor of the interphalangeal joint of the thumb and also assists with metacarpophalangeal extension. Extensor indicis proprius transfer to the EPL is the most widely used and reported treatment for this condition. Magnussen et al. reviewed results of EIP transfer following ruptures of the EPL, with 19/21 good results. None of the cases had any loss of independent index finger extension although index extensor strength reduced to half of that of the contralateral side. Hove et al. reported a similar satisfaction rate following treatment of 15 patients. In his series of 4,400 distal radius fractures treated over a 5 year period, the incidence of delayed tendon rupture following distal radius fracture was 0.3 percent.

The normal fascial components that become diseased and compose the spiral cord include the pretendinous band, spiral band, lateral digital sheet, and Grayson’s ligament. Cleland’s ligament lies dorsal and is not involved with spiral cord formation.

The patient has a perilunate dislocation. A volar dislocation of the lunate is often associated with median nerve dysfunction, which results in decreased sensation on the volar surface of the index finger.

DISCUSSION: The pisotriquetral joint is best seen on a lateral view in 30 degrees of supination. The carpal tunnel view provides visualization of the joint but to a lesser extent. The other views do not provide clear and accurate visualization.

DISCUSSION: The patient has a scaphoid fracture involving the proximal pole. Surgical treatment is recommended for such fractures because of the prolonged period of cast immobilization necessary and the increased risk of delayed union, nonunion, and/or osteonecrosis with nonsurgical management. A cannulated compression screw, inserted in the central scaphoid via a dorsal approach, is biomechanically advantageous and provides greater stability for fracture healing than Kirschner wires. Recently, good outcomes have been reported with arthroscopic-assisted percutaneous fixation of nondisplaced or minimally displaced scaphoid fractures.

DISCUSSION: The carpal tunnel canal has an hourglass shape in the coronal plane and is narrowest at the level of the hook of the hamate. REFERENCES: Cobb TK, Dalley BK, Posteraro RH, et al: Anatomy of the flexor retinaculum. J Hand Surg Am 1993;18:91-99. Trumble TE (ed): Hand Surgery Update 3: Hand, Elbow and Shoulder. Rosemont, IL, American Society of Surgery of the Hand, 2003, p 300.

After major limb replantation, the occurrence of ischemic rhabdomyonecrosis can result in lactic acidosis and myoglobinemia. These complications can be limited by rapid repair of the arterial supply, potentially using a shunt before skeletal stability. Repair of the venous system should be performed after repair of the artery. High volume fluid replacement will maintain a diuresis, thus limiting the complications from myoglobinemia.

This child has Kohler's disease of the navicular. Weight-bearing cast immobilization (for 4-6weeks) is appropriate. Splinting for 2 weeks is insufficient.Idiopathic avascular necrosis (AVN) of the navicular arises because the intraosseous blood flow of the navicular is centripetal, leaving a central watershed area. The primary blood supply is via perforating branches of the dorsalis pedis. Patients present with midfoot pain between 2-9 years of age. Navicular sclerosis, fragmentation, and flattening are noted radiographically.Digiovanni et al. reviewed AVN in the foot. Nonsurgical management is routine. Cast immobilization will provide earlier resolution of symptoms. Weight-bearing will not affect outcome. The navicular will regain a normal appearance over time.Aiyer and Hennrikus reviewed pediatric foot pain. That state that up to 25% of Kohler's disease is bilateral. They agree that casting for 4-6weeks will mitigate symptoms and increase the rate of symptom resolution.Figures A through C are AP, oblique and lateral foot radiographs showing navicular flattening and sclerosis consistent with Kohler's disease.Incorrect Answers:(SBQ13PE.29) A 10-year-old girl presents to your office accompanied by her mother to discuss cosmetic concerns regarding her feet pictured in Figure A. They recently migrated to the U.S. and this is the first medical evaluation for this complaint. The father's feet apparently look similar. The remainder of the patient's physicalexamination is normal. The parents should be counseled that children with this condition have:Review TopicDelayed motor milestones, and cardiac and renal work up are necessaryNormal motor milestones, but cardiac and renal work up are necessaryDelayed motor milestones, but no further work up is necessaryNormal motor milestones, and no further work up is necessaryNo chance of passing on this trait to children, as it results from a spontaneous genetic mutationThis patient has post-axial polydactyly of the feet. Children with this condition exhibit normal motor milestones. If the remainder of the physical examination is normal, no further work up is necessary.Post-axial polydactyly is a common autosomal dominant trait. As such, there is usually a family history. In the absence of other physical exam abnormalities, this condition is not associated with systemic disorders. Normal motor development can be expected, though surgical treatment may be undertaken to facilitate cosmesis or shoe-wear.Phelps et al. reviewed supernumerary digits in 61 patients at an average of 15 year follow up. They found 94% good to excellent results. Poor results were associated with pre-axial duplications and persistent hallux varus.Figure A is a clinical photo showing bilateral post-axial polydactyly of the foot. Incorrect answers:cardiac or renal conditions without any manifestations. Answer 5. This is an autosomal dominant condition.

EXPLANATION: Isolated STT arthritis is common and can cause substantial patient disability and pain. After nonsurgical treatment has failed, surgical intervention is warranted. Surgical options include distal pole scaphoid excision, STT arthrodesis, or carpometacarpal (CMC) arthroplasty, if concomitant thumb CMC degenerative changes are present. Distal pole scaphoid excision is less commonly employed for the treatment of STT arthritis, because of the potential development of intercalated segmental instability. However, distal pole scaphoid excision is less technically demanding, engenders fewer surgical complications, and promotes a faster return to previous activity levels. In any patient with preoperative carpal malalignment, removing the distal pole of the scaphoid would exacerbate that deformity and could lead to symptoms from the DISI deformity. Thus, in this patient with mild DISI deformity seen on preoperative radiographs, STT arthrodesis is the most appropriate treatment option.

Excision of the fracture fragment typically leads to rapid return to function. Fixation techniques are difficult to perform because of the size of the bone; hardware prominence is common. Nerve deficits are not typically noted in this injury. The motor branch of the ulnar nerve in Guyon’s canal must be protected during the surgical approach.

The median nerve courses superficial to the ulnar artery, deep to the fibrous arch of the superficialis muscle, and deep to the superficial head of the pronator teres muscle. The median nerve lies within the interval between the flexor digitorum superficialis muscle and the flexor digitorum muscle as it progresses toward the wrist.

DISCUSSION: Owens and Thordardson cautioned surgeons not to release the conjoined tendon from the base of the proximal phalanx of the great toe because of an increased risk of iatrogenic hallux varus. Release of the transverse and oblique and transverse heads of the adductor hallucis is largely accomplished by releasing the soft tissue adjacent to the lateral sesamoid, without releasing tissue from the base of the proximal phalanx. The conjoined tendon is made up of the flexor hallucis brevis and the adductor hallucis. REFERENCES: Owens S, Thordardson DB: The adductor hallucis revisited. Foot Ankle Int 2001;22:186-191. Sarrafian SK: Anatomy of the Foot and Ankle. Philadelphia, PA, JB Lippincott, 1983, chapter 5.

Complications after carpal tunnel release are relatively uncommon. The clinical picture described above is most consistent with lumbrical muscle weakness secondary to neuropraxia of the proper palmar digital nerve to the index finger supplying motor innervation to that muscle. The recurrent motor branch of the median nerve innervates the thenar musculature and would not present as index finger weakness. A new onset of trigger finger may result from a loss of the pulley effect of the transverse carpal ligament, postoperative tendon inflammation, or previously unrecognized flexor tendon triggering. Flexor digitorum profundus to the index finger lies deep within the carpal tunnel, making its injury unlikely.

The median nerve passes through the pronator teres and deep to the flexor digitorum superficialis. The ulnar artery passes deep to both.

The lunotriquetral interosseous ligament stabilizes the lunotriquetral joint. The scapholunate interosseous ligament stabilizes the scapholunate joint. The ulnolunate ligament originates from the base of the ulnar styloid and inserts in the lunate. The ulnotriquetral ligament originates from the base of the ulnar styloid and inserts on the triquetrum. The ulnolunate and the ulnotriquetral ligaments are important stabilizers to the ulnar side of the wrist. The short radiolunate ligament originates on the volar ulnar margin of the distal radius and inserts in the ulnar margin of the lunate.

This patient sustained fractures of his radius and ulna; both were treated with plate and screw fixation. The plate used on the radius was straight, resulting in loss of the radial bow, which is critical for enabling the radius to curve around the ulna during pronation. This patient is unable to pronate beyond 20°. Schemitsch and Richards correlated a good functional outcome, defined as more than 80% of normal rotation of the forearm, with restoration of the normal amount and location of the radial bow. Additionally, they related the restoration of grip strength with appropriate restoration of the radial bow. Matthews and associates reported little significant loss of rotation with 10° of angulation; however, 20° of angulation resulted in a statistically and clinically significant loss of forearm rotation.

DISCUSSION: Branches of the medial antebrachial cutaneous nerve can often be identified during routine ulnar nerve surgery crossing the medial aspect of the elbow. It should be preserved to avoid development of painful paresthesias.