Range of Normal and Abnormal Syndesmotic Measurements Using Weightbearing CT.

BACKGROUND: Early recognition of syndesmotic instability is critical for optimizing clinical outcome. Injuries causing a more subtle instability, however, can be difficult to diagnose. The purpose of this study was to evaluate both distal tibiofibular articulations using weightbearing computed tomography (CT) in patients with known syndesmotic instability, thereafter comparing findings between the injured and uninjured sides. We also aimed to define the range of normal measurement variation among patients without syndesmotic injury. METHODS: Patients with unilateral syndesmotic instability requiring operative fixation (n = 12) underwent preoperative bilateral ankle weightbearing CT. A separate cohort of patients without ankle injury who also underwent bilateral ankle weightbearing CT were included as comparative controls (n = 24). For each weightbearing CT, a series of 7 axial plane tibiofibular joint measurements, including 1 angular measurement, were utilized to evaluate parameters of the syndesmotic anatomy at a level 1 cm above the tibial plafond. Values were recorded by 2 independent observers to assess for interobserver reliability. RESULTS: Among those with unilateral syndesmotic instability, values differed between the injured and uninjured sides in 4 of the 7 measurements performed including the syndesmotic area: direct anterior, middle, and posterior differences, and sagittal translation (P < .001, < .001, < .001, and < .001, respectively). In the control population without ankle injury, no differences were identified between any of the bilateral measurements (P value range, .172-.961). CONCLUSION: This study highlights the ability of weightbearing CT to effectively differentiate syndesmotic diastasis among patients with surgically confirmed syndesmotic instability from those without syndesmotic instability. It underscores the substantial utility and importance of using the contralateral, uninjured side as a valid internal control whenever the need for confirming potential syndesmotic instability arises. Prospective studies are necessary to fully understand the accuracy of weightbearing CT in diagnosing occult syndesmotic instability among patients for whom the diagnosis remains in question. LEVEL OF EVIDENCE: Level III, comparative diagnostic study.

Effect of Fixation Type and Bone Graft on Tarsometatarsal Fusion.

BACKGROUND:: End-stage tarsometatarsal (TMT) arthritis is commonly treated with arthrodesis of involved joints. Fixation hardware can consist of varying combinations of screws, plates, and staples with or without supplemental bone graft. There are limited data to demonstrate either superiority of a given fixation method or the impact of bone graft on fusion rates. The purpose of this study, therefore, was to determine whether nonunion rates after TMT arthrodesis were influenced by either the use of screw vs plate fixation or the addition of bone graft vs no bone graft. METHODS:: All patients older than 18 years undergoing arthrodesis for TMT arthritis between July 1991 and July 2016 were identified retrospectively. Exclusion criteria included less than 12 months follow-up, prior midfoot surgery, any added procedure beyond TMT arthrodesis using plates or screws, and acute foot trauma. All patients with radiographic or clinical nonunion, including those requiring revision surgery, were identified. Demographic data and associated risk factors were recorded via chart and radiographic image review. Eighty-eight patients (88 feet, mean follow-up: 75.1 ± 51.4; range, 12-179), with a total of 189 joints and who met enrollment criteria were treated by 9 different surgeons with arthrodesis. RESULTS:: The overall nonunion rate was 11.4%. Significant independent risk factors associated with nonunion were (1) arthrodesis using plate fixation with all screws through the plate (odds ratio [OR], 6.2; 95% confidence interval [CI], 1.8-21.3; P = .004), (2) smoking during the perioperative period (OR, 7.9; 95% CI, 2.1-30.2; P = .002), and (3) postoperative nonanatomic alignment (OR, 11.2; 95% CI, 2.1-60.8; P = .005). Bone graft utilization was found to significantly lower the rate of nonunion (OR, 0.2; 95% CI, 0.1-0.6; P = .006). CONCLUSION:: Isolated plate fixation, smoking, and postoperative nonanatomic alignment appear to significantly increase the rate of nonunion among patients undergoing TMT arthrodesis for midfoot arthritis. Concomitant use of autogenous bone graft significantly decreased this risk. LEVEL OF EVIDENCE:: Level III, retrospective comparative study.

Reoperation Rate Differences Between Open Reduction Internal Fixation and Primary Arthrodesis of Lisfranc Injuries.

BACKGROUND: Controversy persists as to whether Lisfranc injuries are best treated with open reduction internal fixation (ORIF) versus primary arthrodesis (PA). Reoperation rates certainly influence this debate, but prior studies are often confounded by inclusion of hardware removal as a complication rather than as a planned, staged procedure inherent to ORIF. The primary aim of this study was to evaluate whether reoperation rates, excluding planned hardware removal, differ between ORIF and PA. A secondary aim was to evaluate patient risk factors associated with reoperation after operative treatment of Lisfranc injuries. METHODS: Between July 1991 and July 2016, adult patients who sustained closed, isolated Lisfranc injuries with or without fractures and who underwent ORIF or PA with a minimum follow-up of 12 months were analyzed. Reoperation rates for reasons other than planned hardware removal were examined, as were patient risk factors predictive of reoperation. Two hundred seventeen patients met enrollment criteria (mean follow-up, 62.5 ± 43.1 months; range, 12-184), of which 163 (75.1%) underwent ORIF and 54 (24.9%) underwent PA. RESULTS: Overall and including planned procedures, patients treated with ORIF had a significantly higher rate of return to the operation room (75.5%) as compared to those in the PA group (31.5%, P < .001). When excluding planned hardware removal, however, there was no difference in reoperation rates between the 2 groups (29.5% in the ORIF group and 29.6% in the PA group, P = 1). Risk factors correlating with unplanned return to the operation room included deep infection ( P = .009-.001), delayed wound healing ( P = .008), and high-energy trauma ( P = .01). CONCLUSION: When excluding planned removal of hardware, patients with Lisfranc injuries treated with ORIF did not demonstrate a higher rate of reoperation compared with those undergoing PA. LEVEL OF EVIDENCE: Level III, retrospective comparative study.