The Variable Insertional Anatomy of the Abductor Pollicis Longus: Functional Relevance and Relationship to Adjacent Thumb Extensors

Background The abductor pollicis longus (APL) is classically described as inserting on the base of the first metacarpal. This study analyzed APL insertional anatomy and quantified the size of various elements of the extensor side of the thumb to determine associations with size and function. Methods Twenty-four formalin-preserved upper limbs were dissected. The insertional anatomy of the APL, extensor pollicis brevis, and extensor pollicis longus were characterized, and the capacity of APL tendon slips to perform palmar abduction of the first digit was quantified based on slip size and insertion. Results The mean number of APL tendon slips observed was 2.3. Abductor pollicis longus insertion sites included the base of the first metacarpal, trapezium, abductor pollicis brevis, and opponens pollicis. Only 4 specimens had a solitary metacarpal slip, while 83% of specimens had insertions onto at least 1 thenar muscle. A total of 62.5% of APL tendons exhibited some form of branching that we categorized into “Y” and “Z” patterns. In assessing palmar abduction capacity, we found that APL tendon slips inserting into the base of the first metacarpal were larger in cross-sectional area than nonmetacarpal slips and reproduced complete palmar abduction of the digit in the absence of nonmetacarpal slips. The abduction capacity of APL tendon slips was not correlated to the cross-sectional area. Conclusions There is significant variability in APL tendon slips, branching patterns, and insertional anatomy. These findings provide further understanding of the function of the APL and its surgical implications.

Suspension arthroplasty in the treatment of thumb carpometacarpal osteoarthritis

Literature presents several examples of surgical techniques for the treatment of carpometacarpal osteoarthritis. In our study we used a modified Ceruso’s suspended arthroplasty technique. In this study, 53 patients from 2011 to 2017 underwent arthroplasty with trapezius excision and suture suspension between abductor pollicis longus and flexor carpi radialis. The average age at surgery was 69, the participants were 43 women and 10 men. The average total operation time was 59 minutes. The modified CMC suspension arthroplasty technique provides excellent results compared with those in the literature.

Anatomical Variations of the Extrinsic Musculature of Thumb

Anatomical variations are commonly encountered during human cadaver dissections. Some of these variations are never discovered unless there is an underlying injury that requires attention. For conceivable clinical and rehabilitation treatments, anatomical modifications may have implications on function therefore it is imperative to report them. This case series depicts the anatomical inconsistency in the muscles and tendons of the extrinsic musculature of the thumb in three human specimens. During a cadaver dissection in physical therapy anatomy course, various anatomical variations were found in three human cadaveric specimens. Cadaver 1 exhibited a new muscle with a split tendon near the distal posterolateral radius. The author uncovered the supplementary muscle between the Extensor Pollicis Longus (EPL) and Extensor Pollicis Brevis muscles. Cadaver 2 had two other extrinsic tendons inserted at the thumb. The Extensor Digitorum provided an extra tendon to the pollicis; a similar insertion as the EPL was recognised. In cadaver 3 an extra muscle belly was observed within the tendon of the abductor pollicis longus. The other muscle variation was near the distolateral attachment at the base of the first metacarpal joint, between the abductor pollicis brevis and extensor carpi radialis muscles. Understanding the diverse anatomical arrangements could prove beneficial for surgeons and those involved in rehabilitating upper extremities. A detailed understanding of the forearm structural anatomy and anomalies is essential to comprehend the function and movements when lesions affect the normal biomechanics within teaching and clinical environments.

Simplified abductor pollicis longus suspension interposition arthroplasty for thumb carpometacarpal joint osteoarthritis

Purpose The primary treatment goals for advanced-stage thumb carpometacarpal (CMC) joint osteoarthritis are complete pain relief and restoration of thumb strength. The purpose of the present study was to introduce a variation of the abductor pollicis longus (APL) suspension arthroplasty using a single looping of a radial slip from the APL tendon around the flexor carpi radialis (FCR) tendon combined with RegJoint™ interposition and to determine its efficacy in the treatment of thumb CMC joint osteoarthritis. Methods Between 2015 and 2017, 21 patients were included. The average age was 60.8 years (range 48–79). The mean follow-up was 27.7 months (range 8–50). Evaluation included pain, radial and palmar abduction, tip pinch and grip strength, and Disabilities of the Arm, Shoulder, and Hand (DASH) score. Results Pain averaged 0.3 (range 0–4) at rest and 1.4 (range 0–4) on exertion. The radial and palmar abduction were 97% and 99% compared to the contralateral side. The tip pinch and grip strength were 4.1 kg (range 3–6.5) and 22 kg (range 13.3–40), respectively. The DASH score accounted for 18.5 (range 0.8–41.7). Conclusion The modified APL suspension interposition arthroplasty was an efficient and simplified option for the treatment of thumb CMC joint osteoarthritis, with results comparable or better than other published procedures. The APL suspension technique was easy to perform avoiding difficult bone tunneling and incision of the FCR tendon. The RegJoint™ interposition as spacer prevented impingement of the first metacarpal base on the second metacarpal base or the trapezoid bone.

Non-S uspensionplasty by Abductor Pollicis Longus Tendon for First Carpometacarpal Osteoarthritis of the Thumb

Many surgical procedures have been described for treating painful osteoarthritis at the carpometacarpal joint of the thumb. We describe the new nonsuspension abductor pollicis longus (APL) arthroplasty of base of the thumb after excision of trapezium. APL arthroplasty formed neojoint scapho-metacarpo-trapezoid joint. This technique is effective, technically straightforward, and appears to be robust.

Trapeziectomy and Abductor Pollicis Longus Suspensionplasty Combined with Extensor Pollicis Brevis Tenodesis for Management of Thumb Basal Joint Osteoarthritis and Metacarpophalangeal Hyperextension

Metacarpal joint hyperextension is common cause of postoperative dissatisfaction after trapeziectomy in the management of basal thumb osteoarthritis. The senior author uses this technique to address this biomechanical problem at the time of trapeziectomy.