Evolution of the Human Hand from Early Hominid to Today
The human body has evolved greatly over time and the hand has shown some of the most intricate changes. Most evolutionary experts attribute this to the greater use of tools facilitated by the early hominid's transition to a bipedal gait. Increased tool use drove these changes by providing a convincing reproductive advantage for early humans. In particular, hand adaptations resulted from two types of grips that were fundamental in our development: the precision grip and the power grip. To fully understand how these changes in development occurred, a review of evolutionary theory will be proffered and further discussion of the unique architecture of the hands of our closest living relatives compared with that of humans will follow. Finally, we will examine the two uniquely human grips, the anatomic adaptations that allowed for their development, and the reasoning behind how these grips provided a compelling reproductive advantage.
Late Repair of Flexor Tendon Lacerations Within the Digital Sheaths
PURPOSE/OBJECTIVE:This article presents the outcomes of repairs of flexor tendon lacerations within digital sheaths performed more than 2 weeks after injury. METHODS:A retrospective review of 46 patients; 37 with finger lacerations involving a total of 54 severed tendons in 42 fingers and nine with thumb lacerations of the flexor pollicis longus (FPL). In those patients with finger lacera- tions, 30 lacerations were isolated to the flexor digitorum profundus (FDP; 17 in Zone I and 13 in Zone II), and 12 involved both FDP and flexor digitorum superficialis (FDS) for a total of 24 tendon lacerations. RESULTS:The delay in surgery for finger lacerations ranged from 2 to 96 weeks (average: 8.5 weeks) and for thumb lacerations, 2 to 17 weeks (average: 5.5 weeks). In Zone I finger lacerations, postoperative flexion of the distal interphalangeal (DIP) joint averaged 35Â° with 82% of patients regaining total active motion (TAM) in the good to excellent range. In Zone II injuries isolated to the FDP tendon, postoperative DIP joint flexion averaged 36.5Â° with 73% of patients regaining good to excellent TAM. In Zone II injuries involving both flexor tendons, final average DIP flexion was 37Â° with only 45% of patients regaining good to excellent TAM. All patients with FPL lacerations regained at least 30Â° (average: 46Â°) of active interphalangeal joint flexion. CONCLUSION/CONCLUSIONS:When certain conditions exist that are deter- mined at surgery, delayed repairs of isolated FDP lacera- tions in fingers and FPL lacerations in thumbs can restore satisfactory mobility. Results are less favorable when both flexor tendons in the finger are lacerated and only the FDP repaired.
Adjunctive Procedures for Median Nerve Decompression in Carpal Tunnel Syndrome An Intraoperative Somatosensory Evoked Potential Study
The objective of this study was to determine the role of ad- junctive surgical procedures on the median nerve for carpal tunnel syndrome as measured by somatosensory evoked potentials (SEPs) on the nerve. Fifty-five median nerves in 47 patients were studied. In each patient, a base-line SEP was recorded in the operating room prior to incision and then intraoperatively following each of three sequential pro- cedures: division of the transverse carpal ligament, an epi- neurolysis of the nerve, and finally, either an epineurotomy or epineurectomy that we refer to as a "limited internal neu- rolysis" since it did not involve any intraneural dissection of fascicles. Comparison of the baseline mean SEP latency for the median nerve, referred to as N19 (negative polarity = 19 msec), showed a statistically significant improvement following each of the three procedures. The average reduc- tion of latency after ligament release alone was 1.52 msec, and the total improvement in latency from baseline through limited internal neurolysis was 4.72 msec. Our study showed that epineurolysis followed by a limited internal neurolysis using either an epineurotomy or epineurectomy produced a significant electrophysiologic improvement in the median nerve. There was no significant difference when comparing epineurotomy and epineurectomy.
Basal Joint Arthritis A Review of Pathology, History, and Treatment [Historical Article]
The basal joint is a collection of articulations at the base of thumb that serve an important function in the overall dexterity of the hand. The unique anatomy of the basal joint provided many evolutionary advantages to the human hand, but also made this joint susceptible to arthrosis and degenerative changes. Surgical treatment of basal joint arthritis has continued to evolve since it was first described in 1949, including excisional arthroplasty, tendon interposition, ligament reconstruction, implant arthroplasty, and arthroscopy. A review of the pathoanatomy, history, and surgical treatments are assessed including a critical review of the literature.
Bridging the Gap in Peripheral Nerve Repair
Peripheral nerve injuries following trauma present an ongoing challenge to the hand surgeon. This review presents an overview of the topic with a historical perspective. Nerve anatomy and nerve injury classifications are discussed followed by a description of the biology of nerve regeneration. Methods used to bridge gaps in peripheral nerve repair are discussed in detail with a critical appraisal of the most recent literature. Recommendations for surgical treatment are formulated based on evidence-based medicine.
Impact of Joint Position and Joint Morphology on Assessment of Thumb Metacarpophalangeal Joint Radial Collateral Ligament Integrity
PURPOSE: A 2-part biomechanical study was constructed to test the hypothesis that coronal morphology of the thumb metacarpophalangeal joint impacts the assessment of instability in the context of radial collateral ligament (RCL) injury. METHODS: Fourteen cadaveric thumbs were disarticulated at the carpometacarpal joint. Four observers measured the radius of curvature of the metacarpal (MC) heads. In a custom jig, a micrometer was used to measure the RCL length as each thumb was put through a flexion and/or extension arc under a 200 g ulnar deviation load. Strain was calculated at maximal hyperextension, 0 degrees , 15 degrees , 30 degrees , 45 degrees , and maximal flexion. Radial instability was measured with a goniometer under 45 N stress. The RCL was then divided and measurements were repeated. Analysis of variance and Pearson correlation metrics were used. RESULTS: The RCL strain notably increased from 0 degrees to 30 degrees and 45 degrees of flexion. With an intact RCL, the radial deviation was 15 degrees at 0 degrees of flexion, 18 degrees at 15 degrees , 17 degrees at 30 degrees , 16 degrees at 45 degrees , and 14 degrees at maximal flexion. With a divided RCL, instability was greatest at 30 degrees of flexion with 31 degrees of deviation. The mean radius of curvature of the MC head was 19 +/- 4 mm. Radial instability was inversely correlated with the radius of curvature to a considerable degree only in divided RCL specimens, and only at 0 degrees and 15 degrees of flexion. CONCLUSIONS: The RCL contributes most to the radial stability of the joint at flexion positions greater than 30 degrees . The results suggest that flatter MC heads contribute to stability when the RCL is ruptured and the joint is tested at 0 degrees to 15 degrees of metacarpophalangeal flexion. CLINICAL RELEVANCE: The thumb MC joint should be examined for RCL instability in at least 30 degrees of flexion.
Diagnosis and treatment of finger deformities following injuries to the extensor tendon mechanism
Injuries to the finger extensor apparatus are very common and may produce chronic deformity and loss of function. Diagnosis is contingent on an understanding of the complex anatomy of this region as well as the ability to perform a careful physical examination. Immobilization is usually the most effective treatment of acute problems. Surgery is often necessary for chronic conditions, but the results are much less predictably corrective.
Correction of the claw hand
Intrinsic paralysis can be the manifestation of a variety of pathologic entities (stroke, cerebral palsy, Charcot-Marie-Tooth, muscular dystrophy, leprosy, trauma, cervical disease, and compressive and metabolic neuropathies). Patients present with a spectrum of clinical findings dependent on the cause and severity of the disease. The 3 main problems caused by intrinsic weakness of the fingers are clawing with loss of synchronistic finger flexion, inability to abduct/adduct the digits, and weakness of grip. Clawing is defined as hyperextension of the metacarpophalangeal joints and flexion of the interphalangeal joints. This article describes the clinical evaluation and surgical treatment options for claw hand
Madelung's deformity: a review [Case Report]
Madelung's deformity is a rare condition of the wrist characterized by a shortened distal radius with volar-ulnar curvature and a dorsally prominent distal ulna. It occurs predominantly in adolescent females who present with pain, decreased wrist mobility, and deformity. Although its aetiology remains unclear, its treatment is becoming more refined. Several different surgical techniques have recently been described in the literature. This review addresses Madelung's deformity and suggests an algorithm for management based on current literature and the authors' own clinical experience
Intraosseous and extraosseous attachments of flexor tendon to bone: a biomechanical in vivo study in rabbits
There are 2 popular methods of repairing flexor tendons to the distal phalanx and attaching a free tendon graft to bone: intraosseous, by implanting the tendon into a bony tunnel, and extraosseous, by suturing the tendon to the cortical surface after elevating the periosteum. An in vivo study was designed to determine whether one method is stronger than the other. The profundus flexor of the third and fourth toes of the hind paw of adult rabbits was divided and reattached to the middle phalanx using either an intraosseous tunnel or an extraosseous suture. Half the rabbits were killed after 3 weeks, the other half after 8 weeks. Repairs were then tested to failure, using an Instron device, and compared with the same tendons in the nonoperated limbs. The repaired tendons demonstrated similar strength 3 weeks and 8 weeks after surgery but were significantly weaker than the nonoperated tendons. The importance of this study is that it gives equal credence to these usual methods of tendon attachment