1. Flexor Pollicis Longus Tendoscopy
Tun Hing Lui, M.B.B.S.(HK), F.R.C.S.(Edin), F.H.K.A.M., F.H.K.C.O.S. 
Arthroscopy Techniques 
Volume 6, Issue 1, Pages e249-e254 (February 2017)
DOI: /j.eats
Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

2. Fig 1
Flexor pollicis longus (FPL) tendoscopy of the left hand. The patient is in supine position. The surface anatomy of the FPL tendon at the thumb, the flexor retinaculum of the wrist, and the flexor carpi radialis (FCR) tendon just proximal to the flexor retinaculum (FR) are marked. The phalangeal portal (PP) is located close to the phalangeal insertion of the FPL tendon and just proximal to the volar interphalangeal crease of the thumb. The wrist portal (WP) is located at the ulnar side of the FCR tendon and 1 cm proximal to the proximal edge of the flexor retinaculum.
Arthroscopy Techniques 2017 6, e249-e254DOI: ( /j.eats )
Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

3. Fig 2
Flexor pollicis longus (FPL) tendoscopy of the left hand. The patient is in supine position. (A) A 2.7-mm Wissinger rod (WR) is inserted into the FPL tendon sheath via the phalangeal portal (PP). An arthroscopic cannula (AC) is inserted along the rod. (B) The rod is removed and the arthroscope (Arth) is inserted into the cannula.
Arthroscopy Techniques 2017 6, e249-e254DOI: ( /j.eats )
Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

4. Fig 3
Flexor pollicis longus (FPL) tendoscopy of the left hand. The patient is in supine position. FPL tendoscopy via the phalangeal portal. (A) The first structure in view is the thenar muscles (TMs). (B) When the arthroscope is retrieved backward, it will go back to the tendon sheath and the FPL tendon can be examined. (C) It is difficult if not impossible to advance the arthroscope proximally along the tendon sheath because of the turn of the FPL tendon at the proximal palm. (Or, orifice of the tendon sheath to the thenar muscles.)
Arthroscopy Techniques 2017 6, e249-e254DOI: ( /j.eats )
Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

5. Fig 4
Flexor pollicis longus (FPL) tendoscopy of the left hand. The patient is in supine position. (A) A 1-cm longitudinal skin incision is made at the wrist portal. The subcutaneous tissue is bluntly dissected down to the deep fascia. The deep fascia is incised open to expose the flexor carpi radialis (FCR) tendon. (B) The FCR tendon is retracted radially to expose the FPL tendon and the radial bursa (RB), which are deep and ulnar to the FCR tendon. (C) A 2.7-mm Wissinger rod (WR) is inserted into the radial bursa at the wrist portal and is advanced distally. An arthroscopic cannula (AC) is inserted along the rod. (D) The rod is removed and the arthroscope (Arth) is inserted into the cannula. (FR, flexor retinaculum; WP, wrist portal.)
Arthroscopy Techniques 2017 6, e249-e254DOI: ( /j.eats )
Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

6. Fig 5
Flexor pollicis longus tendoscopy of the left hand. The patient is in supine position. FPL tendoscopy via the wrist portal. (A) The first structure in view is the thenar space (TS). (B) While the arthroscope is retrieved backward, it will go back to the tendon sheath and the FPL tendon can be examined. (AdP, adductor pollicis muscle; O, orifice to the thenar space.)
Arthroscopy Techniques 2017 6, e249-e254DOI: ( /j.eats )
Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

7. Fig 6
Flexor pollicis longus (FPL) tendoscopy of the left hand. The patient is in supine position. The phalangeal and wrist portals are not coaxial portals even as the thumb is adducted (A) and flexed (B) to align it with the radius. The arthroscope will go to the thenar space via the wrist portal while the arthroscopic shaver will enter the thenar muscles via the phalangeal portal. (C) fluoroscopy confirms that the arthroscope and the shaver are not in line.
Arthroscopy Techniques 2017 6, e249-e254DOI: ( /j.eats )
Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

8. Fig 7
Flexor pollicis longus tendoscopy of the left hand. The patient is in supine position. The thenar portal (TP) and flinger web portal (FWP) can be created by Wissinger rod technique through the phalangeal portal and wrist portal, respectively.
Arthroscopy Techniques 2017 6, e249-e254DOI: ( /j.eats )
Copyright © 2016 Arthroscopy Association of North America Terms and Conditions