Zachary A. Rockov

Clinical Vignette: A 29-year-old woman with no medical history presented after being a pedestrian struck by a motor vehicle. She sustained an APC2 pelvic ring injury, a closed olecranon fracture, and a closed proximal tibia fracture (Fig. 1). Clinical evaluation is notable for significant edema and early serous fracture blister formation overlying the proximal tibia fracture. The patient is neurovascularly intact. Imaging of the tibia demonstrates an extra-articular proximal tibia fracture. The patient underwent application of anterior pelvic external fixation and knee spanning external fixator within 24 hours of arrival.

OBJECTIVES: To evaluate the incidence of anterolateral tibial plafond involvement in pronation-abduction (PAB) ankle fractures and analyze the accuracy of radiographs in detecting anterolateral tibial plafond involvement, impaction, and predicting the need for direct visualization and an articular reduction. METHODS: Design: A multi-institutional retrospective chart review. Setting: Five Level 1 trauma centers in the United States. Patient Selection Criteria: Adult patients with PAB ankle fractures (OTA/AO 44B2.3, 44C2.2, 44C2.3) from 2020 to 2022 were reviewed by 7 fellowship-trained orthopaedic trauma surgeons. They were queried about the presence of anterolateral tibial plafond involvement and impaction, and whether they would need direct visualization and an articular reduction using both radiographs and CT. Outcome Measurements and Comparisons: The presence of anterolateral tibial plafond impaction was tabulated separately using radiographs and CT scans. The accuracy of radiographs and changes in surgical plan after CT review were calculated using CT as the gold standard. RESULTS: Sixty-one fractures in 61 patients were evaluated using CT and/or plain radiographs. Using plain radiographs, anterolateral tibial plafond involvement and impaction were identified in 61% and 36% of cases, respectively. In the 38 fractures with both plain radiographs and CT scans, anterolateral tibial plafond involvement was identified in 66% of radiographs and 74% of CT scans (P = 0.4). Plafond impaction was identified in 42% of plain radiographs and 37% of CT scans (P = 0.62). There was no difference in the rate of involvement between radiographs and CT scan. The diagnosis of anterolateral tibial plafond impaction using plain radiographs was correct in 74% of fractures when compared with using CT imaging, resulting in a sensitivity of 71%, a specificity of 75%, a positive predictive value (PPV) of 62%, and a negative predictive value (NPV) of 82%. Plain radiographs correctly predicted the need for direct visualization and an articular reduction in 74% of cases and had a PPV of 59% and an NPV of 86%. CONCLUSIONS: Anterolateral tibial plafond involvement and impaction were present on CT in 74% and 37% of pronation-abduction (PAB) ankle fractures, respectively. Plain radiographs had higher NPV for identifying impaction and the need for articular reduction than they did sensitivity, specificity, or PPV. CT is an important tool for preoperative planning that should be considered when planning for operative fixation of PAB ankle fractures. Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Category: Ankle; Trauma Introduction/Purpose: Recent studies have reported cadaveric and early clinical data regarding Weber B supination-external- rotation (SER)4a ankle fractures. SER4a ankle fractures have discordance of the medial clear space (MCS) between weight-bearing (WB) and gravity stress (GS) radiographs, showing instability on the GS view which normalizes with WB. Unfortunately, evaluation of the medial clear space only provides a two-dimensional evaluation of a three-dimensional structure. Prior cadaveric research has shown significant decreases in the tibiotalar joint contact area with only 1 mm of displacement of the talus. The purpose of this study is to utilize weight-bearing computed tomography (WBCT) to evaluate differences in the tibiotalar joint contact area and rotational alignment in patients with acute SER4a ankle fractures compared to their contralateral uninjured ankle. Methods: Adult patients presenting within ten days of injury with an isolated Weber B fibula fracture and a normal MCS ( < 5 mm) on injury radiographs were evaluated with weight-bearing and gravity stress radiographs. Patients determined to have isolated Weber B SER4a ankle fractures (GS positive but WB negative radiographs) and no history of injury to the contralateral ankle were included. The ability to place equal weight on both extremities was confirmed by standing on side-by-side scales. WBCT scans were obtained of both the healthy and injured ankles. The images were evaluated using Disior Bonelogic (Paragon28, Helsinki, Finland) software to calculate the tibiotalar joint contact area, axial tibiotalar rotation, and talocrural angle. An a priori power analysis was performed with six patients needed. Results: Five out of ten patients have been enrolled in the study to date (3 females, 2 males, average age 52.4). Preliminary data show an average 4.3% (standard deviation (SD) 4.9) increase in tibiotalar joint contact area between the injured and uninjured extremity. The average difference in axial tibiotalar angle is 3.6 (SD 6.9) degrees of internal rotation of the injured ankle. The talocrural in the injured and uninjured extremity have an average difference of 0.062 (SD 1.8) degrees. Conclusion: This study provides the first in vivo evaluation of the joint contact area changes seen in SER4 ankle fractures. Although limited in sample size, the results demonstrate that SER4a ankle fractures do not have decreased tibiotalar joint contact area relative to the healthy, uninjured side. The trend towards increased surface area in the injured ankles is hypothesized to be a result of the increased reliance on joint congruency with injury to the fibula and deltoid.

Purpose: Arthrofibrosis after primary total knee arthroplasty (TKA) is a significant contributor to patient dissatisfaction. While treatment algorithms involve early physical therapy and manipulation under anaesthesia (MUA), some patients ultimately require revision TKA. It is unclear whether revision TKA can consistently improve these patient's range of motion (ROM). The purpose of this study was to evaluate ROM when revision TKA was performed for arthrofibrosis.Methods: A retrospective study of 42 TKA’s diagnosed with arthrofibrosis from 2013 to 2019 at a single institution with a minimum 2‐year follow‐up was performed. The primary outcome was ROM (flexion, extension, and total arc of motion) before and after revision TKA, and secondary outcomes included patient reported outcomes information system (PROMIS) scores. Categorical data were compared using chi‐squared analysis, and paired samples t tests were performed to compare ROM at three different times: pre‐primary TKA, pre‐revision TKA, and post‐revision TKA. A multivariable linear regression analysis was performed to assess for effect modification on total ROM.Results: The patient's pre‐revision mean flexion was 85.6 degrees, and mean extension was 10.1 degrees. At the time of the revision, the mean age of the cohort was 64.7 years, the average body mass index (BMI) was 29.8, and 62% were female. At a mean follow‐up of 4.5 years, revision TKA significantly improved terminal flexion by 18.4 degrees (p < 0.001), terminal extension by 6.8 degrees (p = 0.007), and total arc of motion by 25.2 degrees (p < 0.001). The final ROM after revision TKA was not significantly different from the patient’s pre‐primary TKA ROM (p = 0.759). PROMIS physical function, depression, and pain interference scores were 39 (SD = 7.72), 49 (SD = 8.39), and 62 (SD = 7.25), respectively.Conclusion: Revision TKA for arthrofibrosis significantly improved ROM at a mean follow‐up of 4.5 years with over 25 degrees of improvement in the total arc of motion, resulting in final ROM similar to pre‐primary TKA ROM. PROMIS physical function and pain scores showed moderate dysfunction, while depression scores were within normal limits. While physical therapy and MUA remain the gold standard for the early treatment of stiffness after TKA, revision TKA can improve ROM.Level of evidence: IV.