Surgical Reconstruction of Type IV Hypoplasia of the Thumb (Floating Thumb) in Infants: A Retrospective Analysis of Functional Outcomes and Radiographic Alignment.

BACKGROUND Congenital hypoplasia of the thumb type IV, also known as floating thumb, is a condition in which 2 small phalanges are attached to the hand with a thin skin bridge. Surgical management options for this condition vary from amputation to flap reconstruction. MATERIAL AND METHODS This retrospective study analyzed 11 infants with congenital hypoplasia of the thumb type IV who underwent surgical reconstruction using a modified vascularized polydactylous hallux flap. The study included 6 male and 5 female infants, aged 6 to 24 months. Functional evaluations and radiographic studies were conducted postoperatively. RESULTS All 11 patients underwent the complete surgical protocol. Successful vascular and nerve anastomoses were performed during the initial procedure, ensuring sufficient blood supply and neural connectivity to the transferred toes. The second operation showed promising outcomes, including improvements in thumb opposition, grasp strength, and overall function. Postoperative assessments demonstrated satisfactory radiographic alignment and no major complications during the follow-up period. CONCLUSIONS The modified vascularized polydactylous hallux flap reconstruction is a viable surgical option for managing congenital hypoplasia of the thumb type IV in infants. This technique effectively restores thumb opposition, grasp strength, and overall hand function, with satisfactory radiographic alignment and minimal complications. The study findings support the efficacy and safety of this surgical approach in addressing this rare congenital anomaly.

Effective shape of ball-and-socket prosthesis in restoring range of thumb motion for total thumb carpometacarpal joint arthroplasty: three-dimensional motion analysis.

PURPOSE: Total joint arthroplasty (TJA) has often been used to treat thumb carpometacarpal (CMC) osteoarthritis (OA). However, guidelines for the CMC prosthesis shape remain unclear. This study aimed to identify the effective shape of a ball-and-socket prosthesis in restoring the range of thumb motion after TJA. METHODS: The participants were 10 healthy young adult men (22-32 years; 26.8 ± 3.57 [mean ± SD]). CT scans were performed in eight static limb positions during abduction and flexion. We defined three design variables (offset R, height H, and neck rotation angle Φ) as the variables that determine the basic shape of the ball-and-socket prosthesis. The ideal values of these design variables were examined based on the results of a 3D motion analysis, which evaluated the change in the posture of the first metacarpal (r, h, and φ corresponding to R, H, and Φ, respectively) relative to the center of rotation (COR) during abduction and flexion. We also simulated the effect of these design variables on the range of thumb motion after TJA using 3D CAD. RESULTS: We found that the values of r and h averaged over all limb positions were 6.92 ± 1.60 mm and 51.02 ± 1.67 mm, respectively, showing that these values remained constant regardless of limb position. In contrast, φ changed significantly. The simulation results indicated that Φ affected the range of thumb motion after TJA, and Φ = 0° relatively reproduced all limb positions compared to other values. CONCLUSION: Our results suggested that the desirable values of R and H were the average of r and h over several limb positions and that Φ = 0° was effective in restoring the range of thumb motion after TJA. Our results will provide surgeons with new guidelines for selecting a prosthesis.

MRI spectrum of injuries to the thumb metacarpophalangeal joint ulnar collateral ligament with a proposed expanded classification of injuries in American football players.

Injuries to the ulnar collateral ligament of the thumb metacarpophalangeal joint are of both historic and modern interest for athletes and non-athletes alike. The thumb metacarpophalangeal joint requires stability in both flexion and extension utilizing a combination of static and dynamic stabilizers. This article reviews the magnetic resonance imaging categorization of thumb ulnar collateral ligament injuries and proposes two additional injury patterns seen in high-level and professional athletes who play American football. In addition to the direct magnetic resonance imaging findings in collateral ligament tears, secondary findings of rotation and subluxation can be seen at the thumb metacarpophalangeal joint due to the altered physiologic forces on the joint. Internal brace augmentation via suture tape of a traditional ulnar collateral ligament repair is a novel surgical technique that provides protection during initial healing and the ensuing remodeling phase following repair or reconstruction, resulting in a faster return to play.

Isolated Palsy of the Anterior Interosseous Nerve to Flexor Pollicis Longus, Magnetic Resonance Imaging and Clinical Correlation: A Case Report.

CASE: Anterior interosseous nerve (AIN) palsy is an uncommon, though well-described, clinical entity. When isolated to the thumb, it can be confused with atraumatic rupture of the flexor pollicis longus (FPL) tendon. A 57-year-old man experienced atraumatic onset of difficulty flexing the distal interphalangeal thumb joint. Magnetic resonance imaging (MRI) demonstrated denervation edema of the FPL, suggesting atypical AIN palsy. Resolution of symptoms and MRI findings occurred concomitantly with nonoperative treatment. CONCLUSION: Atypical AIN palsy limited to the FPL is a rare clinical entity whose diagnosis can be supported with MRI. Here, we report a successful case of nonoperative management.

The Application of Sesamoid Position in Diagnosing Thumb Metacarpophalangeal Joint Dorsal Dislocation: A Retrospective Study.

OBJECTIVES: The position of sesamoid of thumb metacarpophalangeal (MCP) joint changed clearly when the joint was dislocated dorsally. However, the significance of sesamoid location in diagnosing joint dislocation was unclear. The present study aimed to explore the positional relationship between sesamoid bone and thumb metacarpophalangeal joint in normal and dorsal dislocation joints. METHODS: Between January 2018 and August 2023, we collected 60 isometric plain films from sixty outpatients and reviewed 56 anisometric plain films from twenty-eight emergency patients with dorsal dislocation of thumb MCP joint at Tianjin Hospital, then took measurements on the hand X-ray images. The sesamoid length on its longitudinal axis was defined as DP, the distance between the distal edge of sesamoid and thumb MCP joint was defined as DJ, and the ratio of DJ and DP was R. An independent-samples t-test and paired-samples t-test was utilized to analyze difference among data groups. RESULTS: The 60 isometric images were from 30 male and 30 female outpatients with normal bone structure in their hands, and the 56 anisometric images of the 28 emergency patients included both preoperative and postoperative materials. Among the outpatients, the actual distance between the distal edge of sesamoid and thumb MCP joint space (DJ) was 2.09 mm and 1.40 mm in males and females, respectively. The authentic average length of sesamoid (DP) was 4.46 mm in males and 4.22 mm in females. The average value of R (the ratio of DJ and DP) in males and females was 0.49 and 0.34, respectively. There were gender-related statistical differences in DJ (p < 0.01) and R (p=0.01), but no statistical difference in DP (p > 0.05). For the 28 emergency patients, the mean value of R was -0.47 before joint reduction and 0.58 after joint reduction, with statistical difference between them (p < 0.01). CONCLUSIONS: There was significant difference in the relative position between sesamoid and thumb MCP joint when joint dislocation and joint reduction. The distal edge of sesamoid beyond thumb MCP joint could be an evidence in diagnosing joint dorsal dislocation. The distal edge of sesamoid below thumb MCP joint could be an evidence of joint reduction.

Modified Bilhaut-Cloquet procedure for Wassel type III-IV polydactyly.

BACKGROUND: To investigate the functional and aesthetic results of a new modified Bilhaut-Cloquet procedure for the treatment of Wassel type III-IV thumb polydactyly. METHODS: Thirteen patients with Wassel type III-IV thumb polydactyly who visited the Department of Orthopedics of Hebei Provincial Children's Hospital from 2019 to 2022 were selected. The surgical procedure involved a modified Bilhaut-Cloquet surgery, where two-thirds of the distal part of the dominant finger was retained as the p body of the reconstructed thumb. The triangular bone block of the ablated distal thumb that did not contain the epiphysis and articular cartilage was sutured and fixed, and the neurovascular flap of the ablated distal thumb was used as an augmenting segment of the reconstructed thumb, with the nail bed and nail matrix exquisitely sutured. The evaluation performed according to the Japanese Society for Surgery of the Hand (JSSH) system. RESULTS: All 13 children showed bone healing, no wound infection, nonunion, or deformity healing. None of the children showed a significant reduction in the active and passive mobility of the thumb postoperatively compared with preoperatively. Postoperative evaluation was performed based on the JSSH score, with a mean of 17.15 points (14-19 points), with 11 children rated as excellent and two as good. No severe nail ridges, nail gaps, or nail split deformities of the thumb were observed postoperatively. Postoperative metacarpophalangeal and interphalangeal joint movements were not reduced compared with preoperative movements. All parents were satisfied with the appearance and function of the reconstructed thumb. CONCLUSION: The modified Bilhaut-Cloquet procedure designed in this study was satisfactory for Wassel type III-IV thumb polydactyly without affecting the stability of the interphalangeal joints and preserving joint mobility. The postoperative thumb has a comparable circumference and nail width and was cosmetically and functionally satisfactory, especially for the asymmetric two thumbs, which achieved favorable results.

Ultrasonographic characterization of the ulnar collateral ligament of normal thumbs in different age groups

OBJECTIVES: The aim of this study was to perform ultrasonographic characterization of the normal ulnar collateral ligament in different age groups and compare it in men and women and in dominant and nondominant hands. METHODS: Forty right-handed volunteers in the age groups 20-30, 31-40, 41-50, and 51-60 years without a history of trauma or surgical procedure in the studied joint were evaluated. The studied parameters were ligament length, greatest ligament thickness, ligament longitudinal section area in the longitudinal plane, distance from the aponeurosis of the adductor muscle to the metacarpal head surface and joint opening at rest and under abduction stress. RESULTS: The results indicated that the mean values of all parameters had minor variations with age, hand dominance, and gender and were slightly higher in men than in women and in the dominant hand than the nondominant hand. However, a statistically significant difference was observed between the joint opening at rest and under stress. In terms of age, there was a small but nonsignificant decrease in the values, likely because of the natural aging process. CONCLUSION: The low variability in the evaluated parameters indicates that large differences between sides or genders are not to be expected. A greater change is likely to indicate a pathological situation.