| The Surgical Technologist | APRIL 2022 354 JUNE 202 354 Kostretzis et al. Kinematic Alignment Total Knee Revision TABLE 4 | Indications for revision (there were revisions with more than one factor leading to revision indication). Indication N Aseptic component loosening Femoral component 7 Tibial component 6 Both components – Component malpositioning Femoral component Coronal Valgus: 3 Varus: 7 Axial Internal rotation: 4 External rotation: 1 Sagittal Flexion: 1 Tibial component Coronal Valgus: 2 Varus: 3 Axial Internal rotation: 2 External rotation: 10 Sagittal Flexion: 4 Anterior overstuffing Femoral component anteriorized 2 Patella under resection 2 Sizing error Femoral component Oversized: 3; undersized: 2 Tibial component Oversized: 1; undersized: 1 Joint line Distalized: 3 Proximalized: 1 Osteolysis Femoral side 2 Tibial side 2 Both sides 4 Pain as one of the main factors 23 Ligamentous instability 10 Polyethylene wear 2 Septic failure 3 Patellar instability 2 Stiffness 12 stem lengths are presented in Table 5. Thirty-nine (91%) cases required femoral side augments, one case required augments in both femoral and tibial components, and three cases required no augments. A PS tibial insert was used in 31 (72%) cases, while 12 (28%) cases required a more constrained TS insert. The patella was resurfaced during the primary surgery in 39 (91%) cases, kept as is in 20 (47%) cases, and revised in 19 (44%) cases. Four (9%) patella were not resurfaced in any surgery. Mean surgical time was 102 min (66–156, ±18). Mean intraoperative blood loss was 236 ml (50–600, ±121). After a mean post-revision follow-up of 4 years (0.9–7.7, ±2), no patient was lost to follow-up, and there was only one case of reoperation. This case is a female aged 67 years at the time of her index primary TKA in 2012. We performed a revision surgery in 2014 for instability. After the revision, she complained TABLE 5 | Stem length details. Stem length Femur N(%) Tibial N(%) No stem 3 (7%) 5 (11.6%) Stubby/bullet tip 0 12 (27.9%) 50mm 35 (81.4%) 25 (58.1%) 100mm 5 (11.6%) 1 (2.3%) TABLE 6 | Radiographic measurements (negative value represents varus and positive represents valgus). Radiographic measurements Pre-revision Post-revision P-value aHKA mean (min–max, ±SD) −1.8 (−19–7, ±4.4) −0.8 (−5–4, ±2.1) 0.172 mDFA mean (min–max, ±SD) 0.4 (−8–8, ±3.2) 1.7 (−2–5, ±1.6) 0.678 mPTA mean (min–max, ±SD) −2.2 (−11–2, ±2.4) −2.5 (−5–1, ±1.4) 0.518 aHKA, arithmetic mechanical hip-knee-ankle angle (mDFA+mPTA); mDFA, mechanical distal femoral angle; mPTA, mechanical proximal tibial angle; SD, standard deviation. of persisting femorotibial instability. In 2016, we performed a simple polyethylene exchange from a PS to a TS insert. At the final follow-up at 78 months, this patient had a WOMAC score of 61 and a ROM of 0–130◦. There was a total of four adverse events requiring conservative treatment. First, there were two postoperative periprosthetic fractures due to trauma (one undisplaced metaphyseal femoral fracture and one transverse patellar fracture) treated conservatively and healed uneventfully. One patient developed ipsilateral thromboembolic disease and was treated with anticoagulants. Finally, one patient developed a wound complication (localized superficial wound infection) and was treated with antibiotics alone. At the last follow-up, the mean WOMAC score was 34.4 (0– 80, ±21.7). There were 14 (32.6%) patients who complained of persisting knee pain despite knee revision. These patients had a mean WOMAC score of 36.5 (3–71, ±20.5). In most cases, the pain level was reported as improved compared to the pre-revision level and could not be attributed to any specific cause. Two of these patients experienced mild pain associated with unresolved relapsing knee effusion. In one patient, the pain was attributed to a painful neuroma of the infrapatellar branch of the saphenous nerve. Finally, in one patient, the pain was thought to be of neuropathic origin, and the patient was referred to the pain clinic for further treatment. There were no radiolucencies or osteolysis noted on radiographic evaluation. Pre- and post-revision radiographic measurements are provided inTable 6. Case Examples To illustrate the type of cases included in the present cohort, three cases examples are presented. Frontiers in Surgery | www.frontiersin.org 6 August 2021 | Volume 8 | Article 721379
RkJQdWJsaXNoZXIy MTExMDc1