HAND AND WRIST DISEASES Carpal Tunnel Syndrome Carpal tunnel syndrome (CTS) is the most commonly diagnosed and treated entrapment neuropathy. The syndrome is characterized by pain, paresthesia, and weakness in the median nerve distribution of the hand. Surgical and nonsurgical treatments exist that can produce excellent outcomes for patients.
RELEVANT ANATOMY The carpal canal is a fibro-osseous tunnel at the wrist through which 9 flexor tendons and the median nerve pass. The carpal bones define the dorsal aspect of the carpal canal and are shaped in a concave arch. The palmar aspect of the carpal canal is defined by the flexor retinaculum, which bridges the 2 sides of the carpal arch. Intrinsic and extrinsic ligaments of the wrist and hand further stabilize the carpal bones. The carpal canal is narrowest at the level of the hook of the hamate, where the canal averages 20 mm in width.
CTS
Carpal tunnel syndrome
CTSElectrophysiologic diagnostic studies –:1-Nerve conduction:-Median motor and sensory latencies, as well as conduction velocities, are measured across the wrist. A sensory latency of greater than 3.5 milliseconds or a motor latency of greater than 4.5 milliseconds is considered an abnormal finding. 2- Electromyography :-This study must be performed with a clinical differential diagnosis in mind; the abductor pollicis brevis is the key muscle to evaluate. Positive findings in persons with CTS include sharp waves, fibrillation potentials, and increased insertional activity.When interpreting electrophysiologic studies, remembering that CTS is a clinical diagnosis is important. CTS is a constellation of signs and symptoms caused by the compression and slowing of the median nerve at the wrist. Electrodiagnostic studies should not be used independently in making a diagnosis.
NERVE CONDUCTION TEST
Carpal tunnel injection and surgical releaseDupuytren Contracture Dupuytren contracture, a disease of the palmar fascia, results in the thickening and shortening of fibrous bands in the hands and fingers. This disease entity belongs to the group of fibromatoses that include plantar fibromatosis (Ledderhose disease), penile fibromatosis (Peyronie disease), and fibromatosis of the dorsal proximal interphalangeal (PIP) joints (Garrod nodes or knuckle pads). Race, Sex, and Genetics:-The incidence of Dupuytren contracture is highest in Caucasians, historically those of Celtic descent. The disease affects men 7-15 times more often than it does women. Dupuytren disease has long been known to be transmitted in an autosomal dominant fashion with variable penetrance. Neumuller et al (1994) demonstrated an increased relative risk of 2.94 for individuals who express human leukocyte antigen (HLA)-DR3.
Dupuytren Contracture
Dupuytren disease is an autosomal dominant fibroproliferative disease with variable penetrance. Associated conditions:-The incidence of Dupuytren disease also increases with concurrent patient clinical conditions or factors such as diabetes, smoking, chronic alcoholism, seizures, and infection . HIV infection,repetitive manual trauma,Age and family history, younger individuals with a positive family history for the Dupuytren disease have been reported, although the disease most often affects people older than 50 years. (Rheumatoid arthritis is associated with a decreased incidence of Dupuytren contracture).Clinical The typical patient with Dupuytren disease is aged 50 years or older and presents with a palmar nodule and cord adherent to the skin, as well as with a flexion contracture ,Dupuytren disease must be distinguished from several other conditions that affect the hand, including trigger finger, stenosing tenosynovitis, a ganglion cyst, or a soft-tissue mass
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Medical therapy A few important guidelines assist in the management of hand infections. First, cellulitis must be treated with antibiotics. Most hand infections are caused by Staph aureus,and therefore, a first-generation cephalosporin (eg, cephalexin) is usually the first drug of choice. However, the potential exists for infections with different organisms. In fact, an increase in the incidence of community-acquired methicillin-resistant staphylococcal (MRSA) infections has been reported. Animal bites require bacterial coverage that is particular to the offending animal. Human bites require coverage for Eikenella corrodens; penicillin and a first-generation cephalosporin are appropriate choices in these cases. Cat bites require coverage for Pasteurella multocid; appropriate antibiotics include IV ampicillin/sulbactam or oral amoxicillin clavulanate. Usually, oral antibiotics are sufficient as initial treatment. Many medical professionals recommend an initial, limited wound irrigation in the emergency department or in the outpatient clinic. Consider IV antibiotics in patients in whom cellulitis fails to resolve with oral antibiotics. In all cases, the final antibiotic coverage should be guided by culture and sensitivity results. Patients with a history of immunocompromise (including those with diabetes) should initially be treated with IV antibiotics. Fungal infections can occur in or under the skin. Cutaneous fungal infections, or tinea, are treated with topical agents such as miconazole or clotrimazole. The most common subcutaneous infection is sporotrichosis; this condition can appear with an ulcerative lesion, along with lymphadenopathy. Gardeners are most commonly infected. Oral itraconazole for 3-6 months is the current recommended course of treatment. Fungal abscesses or disseminated fungal infections can occur and are usually found in immunocompromised patients. Surgical therapy As a rule, all abscess cavities must be drained. Antibiotics alone are not effective in treating pus. If the patient does not improve with antibiotics, suspect undrained pus or a foreign body. Immunocompromised patients should always receive IV antibiotics.
Ganglion Cyst Ganglion cysts are the most common soft-tissue tumors of the hand and wrist. They can occur in patients of any age, including children; approximately 15% of ganglion cysts occur in patients younger than 21 years. Seventy percent of ganglion cysts occur in patients between the second and fourth decades of life. Women are affected 3 times as often as men. No predilection exists for the right or left hand, and occupation does not appear to increase the risk of ganglion formation. Etiology Uncertainty exists regarding the origin of ganglion cysts. The most widely held physiologic explanation attributes cyst formation to mucoid degeneration of collagen and connective tissues. This theory implies that a ganglion represents a degenerative structure that houses . A more recent theory, postulated by Angelides, attributes cyst formation to trauma or tissue irritation.Modified synovial cells lining the synovial-capsular interface are stimulated to produce mucin. Mucin dissects along the attached joint ligament and capsule to form capsular ducts, which function as valvelike structures producing lakes. The ducts and lakes of mucin eventually coalesce to form a solitary ganglion cyst.
Ganglion cyst
RELEVANT ANATOMY A ganglion is a well-circumscribed mucin-filled cyst with a smooth translucent wall that is closely associated with a joint or tendon sheath. Ganglions are usually connected by a stalk to an underlying joint capsule or ligament. They commonly arise from the dorsum of the wrist, where they are specifically associated with the scapholunate ligament of the wrist. Volar wrist ganglions are less common, and many are associated with the scaphotrapezial joint of the wrist. The location of the radial artery is particularly important in the assessment of volar wrist ganglions because they are often intimately associated with this vessel. Care must be taken to preserve the radial artery during dissection of a volar wrist ganglion because injury to this vessel may potentially compromise circulation to the hand. Clinical Although ganglion cysts are generally asymptomatic, presenting symptoms may include limitation of motion, pain, paresthesias, and weakness. Ganglions are usually solitary, and they rarely exceed 2 cm in diameter. They can involve almost any joint of the hand and wrist. Dorsal wrist, volar wrist, volar retinacular, and distal interphalangeal ganglion cysts constitute the vast majority of ganglions of the hand and wrist. Dorsal wrist ganglia occurring over the scapholunate ligament of the wrist represent 60-70% of all ganglia. The volar wrist is the next most common site of occurrence; 20% of all ganglia occur in the volar wrist. The flexor tendon sheath of the fingers, particularly at the level of the A1 pulley, is involved in 10-12% of ganglia.Imaging Studies Standard plain radiographs are obtained to evaluate any potential underlying bone or joint abnormality that may explain the symptoms. The cyst itself is rarely visualized. For cases with atypical presentations, and especially occult ganglia, MRI studies have proven to be successful in confirming examination findings. Medical therapy The predominant current nonsurgical method of treatment involves aspiration alone,sometimes followed by steroid injection. This is especially successful for tendon sheath ganglions in the hand and digits. Caution should be exercised when performing multiple steroid injections to avoid the complications of skin and fat atrophy and thinning, as well as hypopigmentation. Surgical therapy INDICATIONS:- Indications for treatment include limitation of motion, pain, weakness, and paresthesias. Treatment is also indicated if malignancy is a concern or if the patient finds the lesion aesthetically displeasing..Surgical treatment involves total ganglionectomy with removal of a modest portion of the attached capsule.
Medical therapy Splinting of the thumb and wrist relieves symptoms, but most patients find the loss of the thumb for functional activities too restrictive and do not consistently wear the splints. Injection of corticosteroid into the sheath of the first dorsal compartment reduces tendon thickening and inflammation. A dose of 0.5 mL of 1% plain Xylocaine and 0.5 mL of a long-acting corticosteroid preparation can be injected either sequentially or simultaneously. One injection permanently relieves symptoms in roughly 50% of patients. A second injection given at least a month later permanently relieves symptoms in another 40-45% of patients. Surgical therapy If injection therapy fails, surgical release of the first dorsal compartment relieves the entrapment.