The Effect of Power Grip on Ulnar Variance A Computed Tomography Study of the Wrist and Elbow.

Although an increase in ulnar variance with power grip is well documented in the medical literature, there is a paucity of information concerning its mechanism. This concept was examined in five healthy individuals using computed tomography of their wrists and elbows. Images were obtained of both joints in the resting position and with maximum power grip. Ulnar variance at the wrist increased an average of 0.64 mm (range: 0.3 to 1.2 mm). While the ulnohumeral joint remained unchanged, the radiocapitellar distance shortened an average of 0.62 mm (range: 0.3 to 1.0 mm; p = 0.03), which correlated directly with the change at the wrist. Our study showed that the increase in ulnar variance with grip was due to proximal shift of the radius and not to any distal migration of the ulna, which may have clinical implications in reconstruction or arthroplasty of the elbow.

Collateral Ligament Ruptures of the Thumb Metacarpophalangeal Joint A Review of 500 Surgical Cases.

A retrospective review was conducted of 500 consecutive patients who underwent surgery for complete collateral ligament ruptures of their thumb metacarpophalangeal (MP) joints comprising 362 ulnar collateral and 138 radial collateral ligaments. Complete rupture was confirmed in all cases at surgery. When surgery was carried out within 3 weeks of the injury, reinsertion of the ligament was pos- sible in 98% of cases. When surgery was performed after 3 weeks, reinsertion of the ligament was possible in 45% of ulnar and 68% of radial injuries. Reconstruction utilizing a free tendon graft was required for the other cases. All patients who had surgery within 3 weeks of their injuries regained stable, pain free thumbs. Surgery was less suc- cessful in patients who had surgery after 3 weeks and the failure rate was 5%. Surgery within 3 weeks of the injury permitted re-insertion of the ligament in almost all cases. We propose that avulsions treated within that period be referred to as "acute" injuries and those treated later as "chronic." Treatment of acute injuries is preferred because they rarely require reconstruction, and the results were better than when surgery was performed for chronic injuries. Repair of thumb MP collateral ligaments is predictably possible within 3 weeks of injury but less likely if surgery is delayed after that time period.

Late Repair of Flexor Tendon Lacerations Within the Digital Sheaths.

PURPOSE: 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 35° 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 36.5° with 73% of patients regaining good to excellent TAM. In Zone II injuries involving both flexor tendons, final average DIP flexion was 37° with only 45% of patients regaining good to excellent TAM. All patients with FPL lacerations regained at least 30° (average: 46°) of active interphalangeal joint flexion. CONCLUSION: 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.

Topographic Localization of the Extensor Retinaculum A Cadaveric Study.

PURPOSE: The extensor retinaculum of the wrist, a thickening of the deep forearm fascia, is often used as do- nor graft material for annular pulley reconstructions and bone-retinaculum-bone grafts for ligament reconstructions. The purpose of our study was to identify the relationships between the radial and ulnar styloids, readily recogniz- able topographic landmarks of the wrist, and the anatomic boundaries of the retinaculum. METHODS: The extensor retinacula of 12 preserved, right cadaver wrists (3 male and 9 female) were studied by gross dissection using 3.5-power loupe magnification. The proxi- mal and distal extents of the retinaculum were identified and marked with needles, and their distances from the radial and ulnar styloids measured to determine the lengths of the retinaculum on both sides. RESULTS: The extensor retinaculum on the radial side extended 23.9 ± 2.9 mm proximal to the radial styloid and 5.8 ± 2.6 mm distal to the styloid for a total length of 29.7 ± 3.8 mm. On the ulnar side, the retinaculum extended 2.4 ± 1.4 mm proximal to the ulnar styloid and 17.9 ± 2.6 mm distal to the styloid for a total length of 20.3 ± 2.9 mm. CONCLUSIONS: The extensor retinaculum has a consis- tent relationship with the readily recognized topographic landmarks of the radial and ulnar styloids. The use of the extensor retinaculum as donor material for pulley and liga- ment reconstruction make these findings useful for surgical planning.

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.

Correlation of malrotation deformity in distal radius fractures with radiographic analysis: cadaveric study.

PURPOSE: The radiographic parameters commonly used for evaluating distal radius fractures are radial length, palmar tilt, radial inclination, and articular congruity. Rotation of the distal fragment is not routinely evaluated after distal radius fractures. The purpose of this study was to define the appearance of distal fragment malrotation on conventional radiographs and to correlate varying degrees of malrotation with the corresponding radiographic findings. METHODS: Six distal radiuses from embalmed cadavers were cut and stabilized in 10 degrees, 20 degrees, and 30 degrees of pronated malrotation. Posteroanterior, lateral, and oblique (45 degrees pronated view) radiographs were taken and radiographic measurements were made of radial length, palmar tilt, radial inclination, and rotation. RESULTS: With malrotation, the visible cortical width of the distal fragment mismatched the visible cortical width of the proximal fragment. This was most evident on the oblique view (p < .05) and measured 2.2 mm for 10 degrees of rotation (standard deviation [SD] 0.6), 3.4 mm for 20 degrees of rotation (SD 0.8), and 5.3 mm for 30 degrees of rotation (SD 2.2). CONCLUSIONS: The radiographic parameter of rotation should be considered when evaluating distal radius fracture reduction. Malrotation is best seen on a 45 degrees oblique pronated radiographic view as a mismatch of the cortical width of the distal fragment compared with the cortical width of the proximal fragment. In the absence of radial shortening, a 5.3-mm mismatch is associated with 30 degrees of malrotation and is the upper limit of acceptability.

Cold exposure injuries to the extremities.

Cold exposure injuries comprise nonfreezing injuries that include chilblain (aka pernio) and trench, or immersion, foot, as well as freezing injuries that affect core body tissues resulting in hypothermia of peripheral tissues, causing frostnip or frostbite. Frostbite, the most serious peripheral injury, results in tissue necrosis from direct cellular damage and indirect damage secondary to vasospasm and arterial thromboses. The risk of frostbite is influenced by host factors, particularly alcohol use and smoking, and environmental factors, including ambient temperature, duration of exposure, altitude, and wind speed. Rewarming for frostbite should not begin until definitive medical care can be provided to avoid repeated freeze-thaw cycles, as these cause additional tissue necrosis. Rewarming should be rapid and for an affected limb should be performed by submersion in warm water at 104 degrees to 107.6 degrees F (40 degrees to 42 degrees C) for 15 to 30 minutes. Débridement of necrotic tissues is generally delayed until there is a clear demarcation from viable tissues, a process that usually takes from 1 to 3 months from the time of initial exposure. Immediate escharotomy and/or fasciotomy is necessary when circulation is compromised. In addition to the acute injury, frostbite is associated with late sequelae that include altered vasomotor function, neuropathies, joint articular cartilage changes, and, in children, growth defects caused by epiphyseal plate damage.

A new technique for reconstruction of the ulnar collateral ligament of the thumb.

BACKGROUND: Several previous studies have described reconstructive methods for the treatment of an injury to the ulnar collateral ligament of the thumb. However, there are few biomechanical studies to date to analyze the strength of the surgical reconstruction. PURPOSE: To evaluate 2 reconstruction techniques with use of a cadaveric model: (1) reconstruction with the use of a free tendon graft placed in a figure-of-8 fashion through drill holes in the metacarpal and proximal phalanx of the thumb, and (2) reconstruction with the use of the Bio-Tenodesis Screw System. STUDY DESIGN: Controlled laboratory study. METHODS: Eight matched pairs of cadaveric specimens underwent removal of the proper and accessory ulnar collateral ligaments. One of the 2 reconstruction methods was performed, and specimens were mounted on a materials-testing machine. The specimens were subjected to valgus stress to failure at 30 degrees of flexion. Failure was defined as valgus laxity of 30 degrees at the metacarpophalangeal joint. RESULTS: The peak load to failure was 23.5 +/- 11.4 N for the figure-of-8 reconstruction and 24.3 +/- 12.3 N for the reconstruction using the Bio-Tenodesis Screw System. Comparing the 2 groups, there was no statistically significant difference in peak loads to failure (P = .88). CONCLUSION: There was no statistically significant difference between the peak loads to failure of the 2 reconstructions. CLINICAL RELEVANCE: The Bio-Tenodesis Screw System may provide another viable option for surgical reconstruction of the ulnar collateral ligament of the thumb.

Failed surgery for ulnar nerve compression at the elbow.

Surgical procedures for the treatment of ulnar nerve compression at the elbow are well described. Studies have reported clinical outcomes after decompression of the nerve without transposition and decompression with transposition. Numerous preoperative, intraoperative, and postoperative factors contribute to failure of the surgical procedures. Although the techniques available for revision decompression of the ulnar nerve at the elbow are similar to those used in the primary setting, the results after repeat surgical intervention are less predictable.

Malignant tumors of the hand and wrist.

Malignant tumors in the hand and wrist compose a wide variety of lesions involving skin, soft tissues, and bone. Although these lesions are found elsewhere in the body, many have unique characteristics at this anatomic location. Skin tumors predominate; the most common are squamous cell carcinomas, followed in frequency by basal cell carcinomas and malignant melanomas. Other soft-tissue malignancies are less common but may present more difficult diagnostic problems. They often appear as painless masses that sometimes have been present for months or even years and deceptively appear to be benign. A missed or delayed diagnosis of these tumors can have devastating consequences. Bone malignancies involve both primary lesions, of which chondrosarcomas are the most common, and metastatic lesions. Regardless of cell type, treatment of malignant tumors in the hand and wrist requires special considerations because of the important function of these structures. Orthopaedic surgeons should be familiar with the spectrum of these tumors, the work-up necessary to arrive at a precise diagnosis, and the treatment that will achieve the most favorable outcome.

An unusual rupture of the flexor carpi radialis tendon: a case report.

We present the unusual case of a flexor carpi radialis tendon that ruptured after extended strenuous physical activity by a patient with paralysis of the opposite limb secondary to poliomyelitis.

Tumorlike lesions and benign tumors of the hand and wrist.

A broad spectrum of tumorlike lesions and neoplasms can occur in the hand and wrist, although with somewhat less frequency than in other parts of the body. A thorough understanding of the differential diagnosis of these lesions and a comprehensive strategy for evaluation are central for effective care. Plain radiographs are diagnostic for most bony lesions, whereas magnetic resonance imaging may be necessary to help differentiate a benign soft-tissue lesion from the rare malignant neoplasm. In spite of the complex anatomy, adherence to proper oncologic principles most often will lead to a satisfactory outcome.

Medical history of carpal tunnel syndrome.

The anatomical configuration of the carpal tunnel is that of an inelastic channel. Consequently, any increase in its volume or alteration in shape will usually result in a significant increase in interstitial pressure. At a pressure threshold of 20 mm Hg to 30 mm Hg, epineurial blood flow is compromised. When that pressure is sustained, the symptoms and physical findings associated with CTS appear. Typically, patients present with intermittent pain and paresthesias in all or part of the median nerve distribution of their hand(s). As weeks and months pass, symptoms progressively increase in frequency and severity. Eventually, thenar muscle weakness develops that initially manifests itself as "fatigue," or "tiredness." The progressive increase in symptoms and physical findings, usually accompanied by a progressive deterioration in electrodiagnostic studies, facilitates the classification of the condition into early, intermediate, and advanced stages. The increase in interstitial pressure in the carpal tunnel is in the vast majority of cases idiopathic (spontaneous). It can also be caused by a myriad of other conditions that can be classified into three other categories: intrinsic factors that increase the volume of the tunnel (outside and inside the nerve), extrinsic factors that alter the contour of the tunnel, and repetitive/overuse conditions. In addition, there is another category of neuropathic factors that affect the nerve without increasing interstitial pressure. In rare situations CTS can present as an acute problem. Far less common than the chronic form of the condition, it can follow acute wrist trauma, rheumatologic disorders, hemorrhagic problems, vascular disorders affecting a patent median artery, and high pressure injection injuries. Prompt recognition is important, followed in most cases by urgent surgical decompression of the median nerve.

A meta-analysis of the literature on distal radius fractures: review of 615 articles.

A structured meta-analysis of the available literature was performed to evaluate the outcome of the treatment of displaced intra-articular fractures of the distal radius. A comprehensive search of Medline using the key words "radius" and "fracture" revealed over 4,000 articles. After limiting the search to clinical trials in English and excluding pediatric and geriatric age groups as well as biomechanical and animal studies, 615 abstracts were identified in the period from 1976 to May 1998. Thirty-one articles met the inclusion and exclusion criteria. These included two prospective randomized comparative trials, two non-randomized comparative trials, one half prospective case series and half historical control, and 27 papers on case series. Four papers dealt with external fixation versus closed reduction and cast treatment and one paper looked at open reduction internal fixation with or without additional external fixation. There was insufficient data to perform a scientific meta-analysis because of the poor quality of the studies and lack of a uniform method of outcome assessment. However, the data from the comparative trials showed that external fixation was favored over closed reduction and casting. Additionally, comparing the results of the case series showed that external fixation was superior to internal fixation.

Boxer's Knuckle.

Tear of the dorsal capsule of a finger metacarpophalangeal joint is an uncommon injury that should be differentiated from an injury to the sagittal fibers of the extensor hood. While the latter injury can often be treated nonoperatively, a dorsal capsular injury usually requires surgery, particularly in athletes who are disabled by the injury.

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.

Restoration of opposition.

Opposition is not grasp but a preposition for grasp that involves 3 components of thumb movements: abduction, flexion, and pronation. Thumb opposition is usually lost with paralysis of the thenar muscles innervated by the median nerve. Many opposition transfers have been described that differ in the donor tendon, route of transfer, and method of attachment to the thumb. No one transfer is applicable for every clinical condition, and each transfer has its advantages and disadvantages. Many factors must be evaluated to decide if surgery is likely to be beneficial and then decide on the optimum treatment.

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.