A 42-year-old male presented to our outpatient clinic with a 2-year history of the right ankle stiffness, swelling, and intermittent catching and locking sensation. The patient's medical history and family history were unremarkable. There was no history of trauma. Before the onset of symptoms, he played football regularly.
On physical examination, there was a marked swelling of the right ankle. Passive and active dorsal and plantar flexion were reduced compared to the left ankle. Pain was elicited at extreme passive dorsiflexion and with direct palpation over the anterior ankle. The hyperplantarflexion test produced pain over the posterior aspect of the ankle and feeling of locking. The laxity observed with the anterior drawer maneuver was similar to that of the left ankle. Subtalar motion and midfoot motion were unrestricted and non-tender. Neurological and vascular examinations were normal.
Typical clinical findings on physical examination suggested anterior and posterior ankle impingement syndromes as most likely causes of patient's symptoms, indicating further radiological investigations. Standard anteroposterior (AP) and lateral (LL) radiographs (Fig. 1) showed diffuse swelling of the ankle and osteophytes of the anterior distal tibia and dorsal talar neck. Os trigonum and unexpected soft-tissue mass were detected in the posterior ankle recess, behind the posterior process of the talus. Magnetic resonance imaging (MRI) of the ankle was performed to evaluate the soft-tissue mass (Fig. 2). MRI demonstrated a nodular lobulated soft-tissue mass in the posterior ankle recess measuring 29 x 18 x 19 mm. T1- and T2-weighted images showed heterogeneous mass, with predominantly low-to-intermediate signal intensity. PD-weighted images revealed a high signal intensity halo surrounding the low intensity signal mass. Furthermore, an additional bone fragment, which was not visible on standard AP and LL radiographs was detected on MRI. It was impinged between distal portion of tibia and fibula. Multislice computed tomography of the ankle was also performed to define the morphology of the bony lesions and help more accurate planning of surgical procedure.
The patient's history, clinical, and radiological findings helped to confirm the diagnosis of anterior and posterior ankle impingement syndromes with the presence of a loose body, impinged between tibia and fibula. Because of typical MRI findings for LPVNS, an excisional biopsy of the soft-tissue mass in the posterior ankle recess was indicated to confirm the diagnosis. Due to concurrent presence of anterior and posterior ankle pathology, we decided to use combined two-portal endoscopic hindfoot approach and anterior ankle arthroscopy within the same operative session. The procedure was executed with the patient under spinal anesthesia and in the prone position. A tourniquet was placed around his upper leg but was not inflated. This was done due to good experience of senior authors, who have previously described that not inflating the tourniquet, while using an arthroscopic pump, provides good visualization and good postoperative results in anterior ankle arthroscopy. The hindfoot endoscopy was performed through the posteromedial and posterolateral portals as described by van Dijk et al., and by utilising a 4.0 mm 30  arthroscope. The portals were used interchangeably as viewing or working portals. At the level of subtalar joint, a well-encapsulated, pedunculated, and yellowish-brown nodule was observed. It was cut from the stalk with a radiofrequency wand and the mass was removed from the joint with a grasper (Fig. 3). The specimen was sent for histopathological analysis. Partial synovectomy was then performed at the base of the lesion with the help of a shaver and a radiofrequency wand to achieve complete macroscopic local clearance. Os trigonum and a loose body impinged in the interval between tibia and fibula were also extracted from the posterior ankle recess. After the completion of hindfoot endoscopy, the portals were sutured. The patient was then turned into a supine position, leaving all instruments on a sterile table. The foot and ankle were disinfected again, with new sterile draping applied. Once the patient was adjusted in the supine position, anterior ankle arthroscopy was performed using standard anteromedial and anterolateral portals utilizing a 2-portal dorsiflexion method. An arthroscopic shaver and a radiofrequency wand were used to debride hypertrophic synovium and fibrotic tissue in the anterior ankle recess, including the lateral and medial gutters. A combination of a shaver and a burr was then used to reshape the anterior distal tibia and dorsal talus to their native form. At the end of the procedure, a No. 12 closed suction drain was placed through the anterolateral portal into the joint and the portals were sutured.
The drain was removed on the 1st postoperative day, when patient started with active and passive range of motion (ROM) exercises. A posterior splint with the ankle in the neutral position was used overnight for 3 weeks after the surgery. Weight-bearing as tolerated, with the support of crutches, was allowed for the first 3 weeks after surgery. It was followed by gradual progression to full weight-bearing over the next 3 weeks. During this period, patient underwent a course of physiotherapy, consisting of a ROM and strengthening exercises.
Histopathological analysis confirmed that nodular mass found in the posterior recess of the ankle was indeed a LPVNS (Fig. 4). No recurrence was noted at the final follow-up, 2 years after the surgery. Patient was satisfied with the procedure. He continued playing football several times a week, without any restrictions.