Endoscopic Resection of Giant Cell Tumor of the Extensor Tendon of the Foot  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 2, Pages e303-e309 (April 2017) DOI: 10.1016/j.eats.2016.10.009 Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 1 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. Preoperative magnetic resonance imaging can be used to study the relation between the giant cell tumor (GCT) and the extensor digitorum longus tendon (ET). (A) Coronal view. (B) Transverse view. (C) Sagittal view. Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 2 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. (A) The proximal portal (PP) is located along the extensor digitorum longus tendon (EDL) and just proximal to the giant cell tumor (GCT). The distal portal (DP) is located at the first toe web just distal to the tumor (because the tumor is over the extensor digitorum longus tendon to the second toe in the illustrated case). (B) The working space for endoscopy is developed just superficial to the tumor. Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 3 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. The proximal portal is the viewing portal. The distal part of the dorsal surface of the giant cell tumor (GCT) is cleared by an arthroscopic shaver (S) through the distal portal. Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 4 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. The distal portal is the viewing portal. The proximal part of the giant cell tumor (GCT) is cut open by the SuperCut scissors to expose the extensor digitorum longus tendon (EDL) within the tumor. Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 5 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. The proximal portal is the viewing portal. The extensor digitorum longus tendon (EDL) is dissected from the distal part of the giant cell tumor (GCT) by a retrograde knife (RK). Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 6 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. The proximal portal is the viewing portal, and the distal portal is the working portal. The arthroscopic shaver is placed between the extensor digitorum longus tendon (EDL) and the lateral side of the giant cell tumor (GCT). The plantar surface of the lateral part of the tumor is dissected from the metatarsal (MT) with the arthroscopic shaver (S). Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 7 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. The distal portal is the viewing portal. The extensor digitorum longus tendon (EDL) is identified, and the proximal end of the giant cell tumor (GCT) is mobilized from the underlying metatarsal by the arthroscopic shaver (S) through the proximal portal. Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 8 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. The proximal portal is the viewing portal. The plantar surface of the medial part of the giant cell tumor (GCT) is dissected from the metatarsal (MT) with the shaver (S). Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 9 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. The proximal portal is the viewing portal. The extensor digitorum longus tendon (EDL) is identified and traced distally to the distal end of the giant cell tumor (GCT). The tendon is dissected from the tumor by means of SuperCut scissors (Sc). Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 10 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. The proximal portal is the viewing portal. The distal end of the giant cell tumor (GCT) is mobilized from the metatarsal by the arthroscopic shaver (S). (EDL, extensor digitorum longus tendon.) Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 11 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. The proximal portal is the viewing portal. The giant cell tumor (GCT) is stripped from the metatarsal by means of a small periosteal elevator (PE). Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 12 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. (A) The giant cell tumor (GCT) is removed through the proximal portal (PP). (B) The tumor is placed aside the proximal portal. The size of the proximal portal is approximately the same as the smallest dimension of the tumor. (DP, distal portal.) Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 13 Endoscopic resection of giant cell tumor of extensor tendon in a left foot. The patient is in the supine position. The proximal portal is the viewing portal. The operative field is examined for any residual tumor. The extensor digitorum longus (EDL) and extensor digitorum brevis (EDB) tendons are examined for any injury. Arthroscopy Techniques 2017 6, e303-e309DOI: (10.1016/j.eats.2016.10.009) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions