Thumb Interphalangeal Joint Research Articles

Appficafion of combined wrap-around flap of the big toe and fibial flap of the second toe in treating degloving injuries of the thumb

Objective To report the operation methods and clinical effects of combined wrap-around flap of the big toe and tibial flap of the opposite second toe in treating degloving injuries of the thumb. Melhods Eight cases of thumb degloving injuries were treated with free wrap-around flap from the ipsilateral big toe and tibial lateral-flap from the opposite second toe. In 2 cases, the donor site of the big toe was covered by flap transfer from the side of the adjacent second toe, while the resulting second toe skin defect was covered by full thickness skin graft. In 6 cases full thickness skin graft was used to cover the big toe donor site defects. All donor site defects on the opposite second toe were covered with full thickness skin graft. Results All 8 combined flaps survived. The wound healed primarily. Skin grafts in the donor sites of the foot also survived. Postoperative follow-up ranged from 5 to 18 months, with an average of 8 months. The flap color was the same as normal finger flap without obvious atrophy and pigmentation. The appearance of the thumb was satisfying. Thumb nail grew well. Sensory recovery from S2 to S3 ＋ was achieved in the thumb pulp. Thumb interphalangeal joint tlexion and extension were good. The donor site skin graft had no scar contracture and no ulceration. There were no malformation of toe drop and no impairment of foot function. Conclusion Using combined wrap-around flap of the big toe and tibial flap of the opposite second toe in treating degloving injuries of the thumb could achieved good appearance and function without sacrificing distal segment of the big toe. Key words: Surgical flaps; Transplantation; Microsurgery; Degloving injuries

A Systematic Review of Outcomes of Revision Amputation Treatment for Fingertip Amputations

The purpose of this study was to conduct a systematic review of outcomes of fingertip revision amputation for fingertip amputation injuries in the English-language literature to provide best evidence of functional outcomes. A MEDLINE literature search was performed to identify studies that met the following criteria: (1) reported primary data; (2) included at least five cases of primary revision amputation treatment following digit amputation injury; (3) reported finger or thumb amputation at or distal to the distal interphalangeal (DIP) joint or interphalangeal (IP) joint, respectively; (4) presented at least one of the following outcomes: static two-point discrimination (2PD), cold intolerance, arc of motion (AOM) of metacarpophalangeal (MCP) joints, proximal interphalangeal joints (PIP), DIP joints, or return-to-work time. Thirty-eight studies met the inclusion criteria. Twenty-seven studies reported 2PD, 20 studies reported cold intolerance, eight studies reported AOM, and 18 studies reported return-to-work time after revision amputation of fingertip injuries. The mean 2PD was 5.6mm. On average, 24% of patients experienced cold intolerance. AOM at the PIP joint was reported in four studies and averaged 94°. DIP joint AOM was presented in four studies and averaged 66°. Thumb MCP and IP joint AOM was presented in three and four studies, respectively. Mean thumb MCP joint AOM was 54° and that of the IP joint was 71°. The mean return-to-work time was 47days. On average, fingertip revision amputation can achieve almost normal sensibility and satisfactory motion and patients can expect to return to work on average approximately 7weeks after surgery.

Prevalence of sesamoid bones in the interphalangeal joint of the thumb and fingers: A Radiographic Study

The prevalence of sesamoid bones in the hands has been reported in some previous articles. Most of them, however, have reported sesamoid bones of the metacarpophalangeal joint of the hand and of the interphalangeal (IP) joint of the thumb. The present study investigates the prevalence of sesamoid bones of the IP joint of the thumb and fingers. A retrospective review of radiologic views of the IP joints in the thumb or fingers was performed, including a total of 650 patients (1,096 thumbs or fingers). Sesamoid bones were found in the IP joint of the thumb at 67% (212 of 318), while the index, middle, ring, little fingers had sesamoid bones in the proximal interphlangeal (PIP) joint at 0% (0 of 172), 0.4% (1 of 244), 0.5% (1 of 183), and 1% (2 of 179), respectively. None of the four fingers had sesamoid bones in the distal IP joint. Previous articles have described the similar prevalence to the present study, of sesamoid bones of the IP joint of the thumb, while some others reported the different prevalence. About the PIP joint, no previous articles have found a sesamoid bone. Because the lateral X-ray view is more accurate and suitable to evaluate sesamoid bones, we used the lateral one for the present study. The knowledge that sesamoid bones occurs at these rates in the thumb IP joint and finger PIP joints is helpful to differentiate chip fractures from sesamoid bones near the IP joint, including the PIP joint.

Partially Ossified Iliac Crest Graft for the Reconstruction of the Pediatric Thumb Proximal Phalanx

We present a case of osteomyelitic destruction of the thumb proximal phalanx and interphalangeal (IP) joint in a 3-year-old girl. Such defects are seldom reported, and reconstruction proves to be challenging to obtain potential for digit growth and maintenance of joint function. The phalanx was successfully reconstructed with a free autogenous partially ossified anterior iliac osteochondral crest graft resulting in a functional thumb at 2.5 years post-surgery. We also explore other reports of pediatric phalanx reconstruction with iliac crest grafts and discuss the reconstructive outcomes.

Wrist, First Carpometacarpal Joint, and Thumb Interphalangeal Joint Arthrodesis in Patients With Brachial Plexus Injuries

Wrist arthrodesis, first carpometacarpal joint arthrodesis, and thumb interphalangeal joint arthrodesis can be used in conjunction with other reconstructive measures to improve function and grasp in patients with complete brachial plexus injuries. This study evaluates wrist arthrodesis, first carpometacarpal joint arthrodesis, and thumb interphalangeal joint arthrodesis as measured by fusion rate, complications, and clinical outcomes. A retrospective chart review was performed for 24 skeletally mature patients with brachial plexus injuries treated with wrist arthrodesis by a dorsal plating technique, first carpometacarpal joint arthrodesis by staples, and thumb interphalangeal joint arthrodesis by a tension band wiring technique. Nineteen patients were subjectively evaluated using prearthrodesis and postarthrodesis Disabilities of the Shoulder, Arm, and Hand scores, visual analog pain scores, and a visual analog scale assessing appearance, function, hygiene, ease of daily care, pain, and overall satisfaction. There was 100% union rate with 1 postarthrodesis complication. One patient required wrist fusion plate removal because of painful hardware. Subjective patient assessments showed a statistically significant (P < .001) improvement in Disabilities of the Shoulder, Arm, and Hand scores (from 51 to 28) and pain scores (from 5.3 to 3.2) before and after arthrodeses. The visual analog questionnaire results revealed improvements in appearance, function, daily cares, hygiene, pain, and satisfaction. Wrist arthrodesis, first carpometacarpal joint arthrodesis, and thumb interphalangeal joint arthrodesis had high union rates with minimal complications. Patients benefited from the improved function of their upper extremities and were satisfied with the surgery. The use of wrist, first carpometacarpal joint, and thumb interphalangeal joint arthrodeses in combination should be considered one of the reconstructive possibilities for patients with complete or nearly complete brachial plexus injuries.

Ideal Position for Thumb Interphalangeal Arthrodesis in the Era of Smartphones and Text Communication

The hypothesis of this study was that arthrodesis of the thumb interphalangeal joint at a degree of flexion greater than the recommended 0° to 15° in the era of widespread use of handheld devices would potentially be more beneficial for the use of these devices. For patients who rely heavily on a smart-phone or handheld device and require dominant thumb arthrodesis, thumb interphalangeal arthrodesis at an angle of 10° or 30° will neither improve nor impede their use of the device.

Contribution of Flexor Pollicis Longus to Pinch Strength: An In Vivo Study

To estimate the contribution of the flexor pollicis longus (FPL) to key pinch strength. Secondary outcomes include tip pinch, 3-point chuck pinch, and grip strength. Eleven healthy volunteers consented to participate in the study. We recorded baseline measures for key, 3-point chuck, and tip pinch and for grip strength. In order to control for instability of the interphalangeal (IP) joint after FPL paralysis, pinch measurements were repeated after immobilizing the thumb IP joint. Measures were repeated after subjects underwent electromyography-guided lidocaine blockade of the FPL muscle. Nerve conduction studies and clinical examinations were used to confirm FPL blockade and to rule out median nerve blockade. Paired t-tests were used to compare pre- and postblock means for both unsplinted and splinted measures. The difference in means was used to estimate the contribution of FPL to pinch strength. All 3 types of pinch strength showed a significant decrease between pre- and postblock measurements. The relative contribution of FPL for each pinch type was 56%, 44%, and 43% for key, chuck, and tip pinch, respectively. Mean grip strength did not decrease significantly. Splinting of the IP joint had no significant effect on pinch measurements. FPL paralysis resulted in a statistically significant decrease in pinch strength. IP joint immobilization to simulate IP joint fusion did not affect results. Reconstruction after acute or chronic loss of FPL function should be considered when restoration of pinch strength is important.

The Crossover Composite Filet of Hand Flap and Heterotopic Thumb Replantation

Sir: The extremity filet flap offers ideal tissue with limited donor-site morbidity. After nonreplantable traumatic upper extremity amputation, preservation of length can be crucial for proper fitting of a prosthesis, and the filet flap has served in this capacity.1-3 In an effort to maintain a prehensile hand, heterotopic digital replantation is also often used. We present a unique scenario in which a crossover composite filet of hand flap was used for coverage of an extensive contralateral hand wound combined with a heterotopic thumb replantation. A 46-year-old woman presented following jumping in front of a subway train with traumatic amputation of her right upper extremity at the proximal humeral level, traumatic amputation of her left thumb, and severe degloving of her left hand (Fig. 1). Secondary to delayed presentation and extensive elbow injury, replantation of the right upper extremity was not attempted. Instead, an extended filet of hand flap was designed to include both the palmer and dorsal surfaces of the hand and the thumb (Fig. 2). The extensor pollicis longus and flexor pollicis longus were identified and harvested at their musculotendinous junction. The thumb was disarticulated at the basal joint. The thumb sensory nerves, radial sensory nerve, dorsal ulnar sensory nerve, radial artery, and multiple veins were included within the flap. All similar structures were prepared on the left hand.Fig. 1: Preoperative image of the left hand degloving injury and thumb avulsion injury.Fig. 2: Composite filet of hand and thumb flap. EPL, extensor pollicis longus; FPL, flexor pollicis longus; APL, abductor pollicis longus; EPB, extensor pollicis brevis.Secondary to ischemia time, the revascularization (one artery end-to-side, and two veins) was completed first. The recipient-site metacarpal stump was smoothed and a matching amount of metacarpal base was removed from the flap. Fixation was completed with Kirschner wires. The tendons and all nerves were repaired and the skin was closed over the defect. There was 100 percent flap survival. Three additional operations were required for further débridement and limited skin grafting of the native left hand. At 9 months, the patient had a viable left hand and thumb (Fig. 3). She has limited thumb sensation, but this may continue to improve. She has minimal thumb interphalangeal or metacarpophalangeal joint motion but has a functional post. She has range of motion in abduction and adduction of 45 and 15 degrees, respectively. She is able to use her left hand for normal daily activities, including writing.Fig. 3: Nine months after left thumb and hand reconstruction using the crossover composite filet of hand and thumb flap.The classic filet flap involves harvest of an axial pattern flap from a nonsalvageable extremity allowing wound coverage without increased donor-site morbidity.2 We present a variant of this typical flap with harvest of a crossover composite filet of hand and thumb flap. Crossover flaps have been used in both bilateral lower extremity4 and upper extremity amputations.5 In this case, an alternative option would have involved a temporizing procedure followed by multiple microvascular procedures. Our approach offered several advantages, including an immediate reconstruction allowing early rehabilitation and a superb reconstruction without donor-site morbidity. Other reconstructive options would have involved sacrificing another digit either on the hand or the foot. We were able to provide a reconstruction with very similar tissue, allowing preservation of function in an otherwise severely debilitating injury. DISCLOSURE The authors have no financial interest to declare in relation to the content of this article. Nicholas T. Haddock, M.D. Hospital of the University of Pennsylvania Philadelphia, Pa. David A. Ehrlich, M.D. Jamie P. Levine, M.D. Pierre B. Saadeh, M.D. New York University Langone Medical Center Institute of Reconstructive Plastic Surgery New York, N.Y.

Idiopathic Multicentric Osteolysis: Upper Extremity Manifestations and Surgical Considerations During Childhood

Idiopathic multicentric osteolysis (IMO) is an uncommon disease presenting during childhood with resorption of the carpus and tarsus with nephropathy. The few case reports and literature reviews do not focus on the upper extremity disease manifestations or surgical treatment options. We review our experience with the upper extremity in IMO. We evaluated 8 affected children, specifically assessing early disease manifestations, misdiagnoses, radiographic progression, and surgical treatments rendered. Wrist pain and swelling are typically the first manifestations of IMO. Characteristic upper extremity findings, once the disease has progressed, include metacarpophalangeal joint hyperextension, wrist ulnar deviation and flexion, and loss of elbow extension. Radiographically, there is osteolysis of the carpus and proximal metacarpals with resorption of the elbow joint in some patients. Surgical treatments, including soft tissue release with pinning or joint arthrodesis, may offer pain relief and improve alignment, but outcomes are inconsistent. Children with IMO are almost always misdiagnosed initially, and the correct diagnosis may be delayed by years. The hand surgeon is ideally suited to provide an accurate diagnosis of IMO, because wrist pain and swelling and thumb interphalangeal joint contracture are common early manifestations. Prognostic IV.

Bilateral Dupuytren's contractures of the thumb interphalangeal joints

Dupuytren's disease was first described by Baron Guillaume Dupuytren in 1831. He outlined the pathology of palmar fascia thickening and contracture resulting in flexion of one or more digits. Dupuytren's disease usually affects the little or ring fingers, with the thumb rarely affected. Furthermore, the thumb in isolation is only affected in 0.5% of cases, with contracture at the metacarpophalangeal joint. We present a unique and interesting case of Dupuytren's disease predominantly of the thumbs, with isolated contractures bilaterally at the interphalangeal joints, in a 59 year old lady with epilepsy who was otherwise fit and well. To our knowledge this disease pattern has never been reported in the literature. Furthermore a relevant literature review of Dupuytren's disease affecting the thumb, in particular the interphalangeal joint, is presented. Our interesting and unique case reinforces the notion that the disease pathogenesis is diverse and multifactorial, and provides a further interesting example for the literature.

Monozygotic twins discordant for pediatric trigger-locked thumbs

Pediatric trigger-locked thumb (PTLT) is a condition frequently encountered by hand surgeons. The term pediatric is more accurate than congenital because most cases do not present at birth. It is possible however that some children are born with the condition but it manifests after birth. The etiology, natural course, ideal treatment, and the age for surgical intervention were all debated in the literature. Children with PTLT typically present under the age of four with the interphalangeal (IP) joint of their thumb locked in flexion. The condition however is seldom preceded by catching, snapping, or triggering of the thumb, which may cause dysfunction and pain. A disparity in the size between the flexor tendon and the surrounding retinacular pulley system, most commonly at the level of the first annular (A1) and partly the oblique pulleys, results in difficulty of flexor pollicis longus tendon gliding hence the triggering/locking phenomenon. This abnormality typically presents at a mean age of two with the IP joint locked in flexion with a palpable nodule in the flexor pollicis longus tendon called Notta’s node. One study observed that in 8.5 % of the cases the condition was diagnosed in the first 2 months following birth, in 53.2 % of the cases between 2 months and 2 years, and in the remainder after 2 years of age [1]. There is some debate about the presentation and whether this condition is truly congenital and present at birth, the pathology is present at birth but manifests later in infancy and childhood, or truly acquired and develops after birth. For these reasons, the term pediatric trigger-locked thumb is more encompassing. The incidence of acquired or pediatric trigger thumb in children under 1 year of age is 33 per 10,000 live births. Bilateral involvement is reported between 25 and 50 % [1, 4]. The treatment of PTLT is releasing the stretched A1 and part of the constricting oblique pulley and restoring flexor tendon excursion and thumb IP joint extension. There has been limited number of literature publications on the etiology of PTLT. The few articles available in the literature on this topic suggest that genetic factors are important in its etiology [5–8, 10, 11]. There are three case reports of “congenital trigger thumb” in twins [3, 4, 8] that support the genetic factors in the etiology of the condition. These reports are based on the fact that the condition occurred in “identical” twins but without a proof of the monozygotic nature of the twins with DNA analysis. We report a case of monozygotic twins discordant for the condition: one with bilateral congenital trigger-locked thumbs and the other with no thumb abnormalities.

Target-focused Exercise Regime: A Motivational Strategy to Improve Patient's Adherence to Treatment of a Stiff Thumb Interphalangeal Joint

As hand therapists, we are often creative in altering and individualizing orthoses to meet specific patient needs. To assist patients in regaining desired thumb interphalangeal joint range of motion, these authors added a target component to a standard short opponens orthosis. This target component allowed patients to visualize the range of motion goal, thus subjectively resulting in better patient compliance and range of motion.—Victoria Priganc, PhD, OTR, CHT, CLT, Practice Forum Editor As hand therapists, we are often creative in altering and individualizing orthoses to meet specific patient needs. To assist patients in regaining desired thumb interphalangeal joint range of motion, these authors added a target component to a standard short opponens orthosis. This target component allowed patients to visualize the range of motion goal, thus subjectively resulting in better patient compliance and range of motion.—Victoria Priganc, PhD, OTR, CHT, CLT, Practice Forum Editor JHT Read for CreditQuiz: Article #234Record your answers on the Return Answer Form found on the tear-out coupon at the back of this issue or to complete online and use a credit card, go to JHTReadforCredit.com. There is only one best answer for each question.#1.The target component was placed towarda.radial deviationb.ulnar deviationc.flexiond.extension#2.The desired weekly progression was established as an increase of approximatelya.10°–15°b.15°–20°c.20°–25°d.5°–10°#3.The authors present their work as aa.single case studyb.random clinical trials designc.series of cases with definitive diagnosesd.clinic wide experiential report#4.Though the reader cannot be sure, one can presume that goals and gains were expressed as increases ina.composite flexionb.lag reductionc.AROMd.PROM#5.The authors took into account the severity of the stiffness by using the Modified Weeks Test before setting goalsa.Trueb.the descriptive paper does not sayWhen submitting to the HTCC for re-certification, please batch your JHT RFC certificates in groups of 3 or more to get full credit. Quiz: Article #234Record your answers on the Return Answer Form found on the tear-out coupon at the back of this issue or to complete online and use a credit card, go to JHTReadforCredit.com. There is only one best answer for each question.#1.The target component was placed towarda.radial deviationb.ulnar deviationc.flexiond.extension#2.The desired weekly progression was established as an increase of approximatelya.10°–15°b.15°–20°c.20°–25°d.5°–10°#3.The authors present their work as aa.single case studyb.random clinical trials designc.series of cases with definitive diagnosesd.clinic wide experiential report#4.Though the reader cannot be sure, one can presume that goals and gains were expressed as increases ina.composite flexionb.lag reductionc.AROMd.PROM#5.The authors took into account the severity of the stiffness by using the Modified Weeks Test before setting goalsa.Trueb.the descriptive paper does not sayWhen submitting to the HTCC for re-certification, please batch your JHT RFC certificates in groups of 3 or more to get full credit. Record your answers on the Return Answer Form found on the tear-out coupon at the back of this issue or to complete online and use a credit card, go to JHTReadforCredit.com. There is only one best answer for each question.#1.The target component was placed towarda.radial deviationb.ulnar deviationc.flexiond.extension#2.The desired weekly progression was established as an increase of approximatelya.10°–15°b.15°–20°c.20°–25°d.5°–10°#3.The authors present their work as aa.single case studyb.random clinical trials designc.series of cases with definitive diagnosesd.clinic wide experiential report#4.Though the reader cannot be sure, one can presume that goals and gains were expressed as increases ina.composite flexionb.lag reductionc.AROMd.PROM#5.The authors took into account the severity of the stiffness by using the Modified Weeks Test before setting goalsa.Trueb.the descriptive paper does not say When submitting to the HTCC for re-certification, please batch your JHT RFC certificates in groups of 3 or more to get full credit.

Management of Pediatric Trigger Thumb and Trigger Finger

Pediatric trigger thumb and trigger finger represent distinct conditions and should not be treated like adult acquired trigger finger. Over the last two decades, our understanding of the natural history of pediatric trigger thumb and the etiology and surgical management of pediatric trigger finger has improved. Pediatric trigger thumb may spontaneously resolve, although resolution may take several years. Open surgical release of the A1 pulley of the thumb is an alternative option that nearly uniformly restores thumb interphalangeal joint motion. Surgical management of pediatric trigger finger with isolated release of the A1 pulley has been associated with high recurrence rates. Awareness of the anatomic factors that may contribute to triggering in the pediatric finger and willingness to explore and address other involved components of the flexor mechanism can prevent surgical failure.

Distribution of finger nodes and their association with underlying radiographic features of osteoarthritis

To determine the distribution of clinically palpable hand interphalangeal (IP) nodes at each finger and thumb joint in a population with nodes, the influence of left or right hand dominance and sex on the development of nodes, and the association between nodes and underlying radiographic features of osteoarthritis (OA). We performed a cross-sectional analysis of participants in the Genetics of Osteoarthritis and Lifestyle (GOAL) study who had ≥1 Heberden's nodes or Bouchard's nodes on clinical examination. Frequencies (%) of nodes were described for each IP joint in the hand. Associations between nodes and underlying radiographic OA were shown with odds ratios (ORs) and 95% confidence intervals. A logistic regression model was used to adjust for the following confounding factors: age, sex, body mass index, left or right hand dominance, hand trauma, occupation with heavy manual activity, and participation in sports. Of the 3,170 GOAL participants, 1,939 had ≥1 nodes (mean age 68 years, 54% women). The distal IP joints of the index finger were the most frequently affected, followed by the thumb IP joint. Nodes were more common in dominant hands and women. There was a significant association between nodes and underlying radiographic OA (OR range 2.26-21.23). This association was stronger for joint space narrowing than for osteophytes. A dose-response relationship was found between clinical severity of Heberden's nodes and underlying radiographic change. Our study supports the positive association between nodes and radiographic OA, especially narrowing, and the influence of sex and left or right hand dominance on development of nodes. In this age group, presence of nodes may be taken as an indication of underlying small joint OA.

Painful Clicking of the Thumb Interphalangeal Joint Caused by a Sesamoid Bone: A Report of Three Cases

Painful clicking of the interphalangeal joint of the thumb caused by a sesamoid bone is rare. We present 3 cases of painful thumb interphalangeal joint clicking with motion, all following hyperextension injuries. No other source of symptoms was determined, and in each instance the sesamoid was removed. All patients were clinically assessed at 2 years after surgery and were noted to have relief of pain and clicking with full recovery of strength and activities.

LINBURG-COMSTOCK PHENOMENON FOLLOWING FOREARM LACERATION

A 20-year-old man presented with an inability to flex the interphalangeal joint of the right thumb without simultaneous flexion of the distal interphalangeal joint of the index finger following a penetrating injury to the right forearm. With a clinical suspicion of intertendinous adhesions between the flexor pollicis longus and the flexor digitorum profundus to the index finger, surgical exploration under wide-awake anesthesia was performed. Intraoperatively, the intertendinous adhesions were identified and divided completely. Postoperatively, the patient achieved good, independent flexion of the interphalangeal joint of the thumb. This case demonstrates a clinical picture similar to that of Linburg-Comstock syndrome, which occurred following a forearm penetrating injury. We call this the Linburg-Comstock (LC) phenomenon.

NAIL DYSTROPHY IN PSORIATIC ARTHRITIS PRESENTING AS NAIL ONYCHOMYCOSIS: A CASE REPORT

Dystrophic nail changes without a skin lesion is a rare form of psoriasis. We describe a patient that presented with a chronic nail onychomycosis and a destructive thumb interphalangeal joint which was initially considered as onychomycotic joint infection, and was later diagnosed as having dystrophic nail changes in psoriatic arthritis and coexistent onychomycosis. The nail changes were completely normalized after methotrexate treatment.

Motor somatotopy of extensor indicis proprius and extensor pollicis longus

After tendon transfer of extensor indicis proprius (EIP) to extensor pollicis longus (EPL), rehabilitation is initiated to enhance motor cortex reorganization. However, patients have been described showing thumb extension immediately after the tendon transfer. At cortical level, no evidence supports either of these assumptions. We noninvasively investigated motor cortical source locations of EIP and EPL muscles. Magnetoencephalography was used to identify motor somatotopic map in healthy right-handed participants, who performed voluntary extension at index metacarpophalangeal joint and thumb interphalangeal joint. Motor cortical representation of EIP was more medial than cortical representation of EPL, with mean Euclidean distance of 15.4±2.7 mm. Motor somatotopic map of EIP/EPL that was obtained by magnetoencephalography supports 'functional somatotopy' representation of the finger in primary motor cortex.

Rotation in the Interphalangeal Thumb Joint In Vivo

To investigate rotation at the thumb interphalangeal (IP) joint in vivo to optimize the position of fusion of this joint. Standardized photographs were taken of 176 thumbs end-on (88 asymptomatic volunteers) placed on a custom-made splint with the IP joint at 40 degrees . Three blinded investigators measured rotation at the IP joint from these photographs as the angle between a line aligning the eponychial folds and a line aligning the proximal phalanx condyles. Gender, age, hand dominance, and type of occupation of the asymptomatic vounteers were recorded. The variable pronation at the IP joint of the thumb (range, 0 degrees to 12 degrees) was significantly greater on the left than right (p=.001), although the actual difference was only 1 degrees . In subjects who performed fine dexterous work, thumb IP joint pronation was significantly less than in subjects who performed administrative or manual work (p=.009), but we found no statistical difference between manual and administrative groups. There was no correlation between thumb IP joint rotation and hand dominance (p=.2), age (p=.4) or gender (p=.5). There is functional pronation at the IP joint of the thumb. We propose that this should be taken into account when performing arthrodesis on the joint or designing a joint replacement. The degree of rotation may be associated with occupation.

Irreducible Dislocation of the Thumb Interphalangeal Joint With Digital Nerve Interposition: Case Report

Irreducible open dislocation of the thumb interphalangeal joint is a rare injury with several factors responsible for blocking reduction. We describe a case of a 32-year-old man who, on surgical exploration, was found to have an irreducible thumb dislocation due to flexor pollicis longus tendon, ruptured volar plate, and the digital nerve interposed in the interphalangeal joint.