We sought to document the incidences of deep vein thrombosis (DVT) before and after total knee arthroplasty (TKA). In addition, we aimed to explor whether routine preoperative DVT evaluation was useful to establish DVT treatment strategies after TKA. Finally, we wanted to evaluate whether the incidences of DVT differed between patients undergoing unilateral and staged bilateral TKA within the same hospitalization period. The retrospective study included 153 consecutive patients (253 knees) with osteoarthritis who underwent primary TKA. After surgery, mechanical compression devices (only) were used for DVT prophylaxis. DVT status before and after TKA was determined via 128-row, multidetector, computed tomography/indirect venography. Overall, the preoperative DVT incidence was 2.6% per patient and 1.6% per knee. All preoperative DVTs were distal in nature and asymptomatic. After TKA, newly developed thrombi were evident in various calf veins, without propagation of any pre-existing thrombi. Postoperatively, the overall incidences of DVT were 69.9% per patient and 58.5% per knee. The DVT incidences were 66% per patient and 69.8% per knee in the unilateral TKA group. In contrast, the incidences were 72% per patient and 55.5% per knee in the staged bilateral TKA group. There was one case of symptomatic distal (unilateral TKA; 0.65% per patient and 0.4% per knee) and proximal DVT (bilateral TKA; 0.65% per patient and 0.4% per knee), respectively. The incidence of symptomatic DVT was low in Asian patients treated with mechanical compression devices alone, although substantial portion of patients had DVT after surgery. Routine preoperative DVT evaluation is probably not necessary; preoperative DVT was rare and of limited clinical relevance. Furthermore, staged bilateral TKA during a single period of hospitalization does not increase the incidence of DVT.

Lee JH, et al. Clin Orthop Surg. 2020 Jun;12(2):245-251. https://doi.org/10.4055/cios19123

Background: The os subfibulare is usually asymptomatic and found incidentally on radiographs. However, sometimes it may cause subfibular pain and may be associated with chronic lateral ankle instability (CLAI). We hypothesized that os subfibulare could interrupt the talofibular space causing impingement, resulting in chronic pain and functional instability around the lateral malleolus. The purposes of this study were to analyze morphologic characteristics of os subfibulare, and to evaluate the clinical significance of the os subfibulare in patients with CLAI. Methods: Between November 2011 and April 2015, 70 patients who had both computed tomography (CT) and magnetic resonance imaging (MRI) among 252 patients who visited our hospital with the symptom of lateral ankle instability were included in this study. The location of the ossicle was classified into 3 zones in reference to the attachment site of the lateral ankle ligaments. The impingement was classified into 2 groups according to the presence of talofibular encroachment. Digital radiographs were used to measure the ossicle width and shape determined by the length and width on an magnetic resonance (MR) image. Results: The most common shape of ossicles was oval, and the most common location of ossicles was at the anterior talofibular ligament (ATFL) attachment site. Sixty-one percent of patients showed talofibular impingement on coronal MR images. In 48 cases, the dimension of fibula plus os subfibulare was larger than that of the contralateral normal fibula. The larger size and talofibular impingement of the ossicle were associated with greater need for operative treatment in patients with ankle instability. Conclusion: The morphologic analysis of the os subfibulare revealed that there might be impingement of the talofibular space by the ossicle in some patients. We suggest that morphologic characteristics of the os subfibulare should be considered when selecting treatment options in patients with CLAI and os subfibulare. Level of Evidence: Level III, retrospective comparative series.

Patellar fractures are characterized by injuries to the extensor and typically require surgical fixation. Among the methods used for fixation, the most common is the modified AO tension-band wiring technique. However, using this technique, implant migration occurs due to the lack of connections between the K-wires and the tension-band wire, which causes irritation and reduces fracture stability. Recently, new methods for tension-band wiring have been developed in which tension bands lock the K-wires through an attached “ring” to prevent migration. The purpose of this study was to compare the clinical outcomes when either the conventional or novel technique was used for tension-band wiring. This was a retrospective study involving 48 patients who underwent tension-band wiring to correct a patellar fracture. Patients in group 1 (n = 23) were treated between December 2010 and February 2012 using conventional tension-band wiring, while patients in group 2 (n = 25) were treated between March 2012 and May 2014 using the novel ring pin method. Different surgeons performed the operations in the two groups, while all other conditions were consistent. The surgical outcomes were assessed according to the level of implant migration, irritation, and implant removal procedures. All patients in group 2 achieved a union of the patella, while two patients in group 1 did not. These two patients underwent partial patellectomy within 1 year of the initial surgery. Implant migration and removal were significantly more common among patients in group 1 (p = 0.0038 and 0.011, respectively), with the implant removal period being significantly shorter as well (p = 0.005). The novel ring pin method was superior to the conventional method in terms of preventing implant migration, removal, or other secondary operations for the correction of complications.