Brian C. Werner, M. Tyrrell Burrus, Austin M. Looney , [...]
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Abstract
Background:
Total ankle arthroplasty (TAA) and ankle arthrodesis (AA) are two operative options for the management of end-stage ankle arthritis that has failed conservative interventions. Obesity is associated with a greater incidence of musculoskeletal disease, particularly osteoarthritis of the weight-bearing joints, including the ankle. The objective of the present study was to use a national database to examine the association between obesity and postoperative complications after TAA and AA.
Methods:
The PearlDiver database was queried for patients undergoing AA and TAA using International Classification of Diseases, 9th Revision (ICD-9) procedure codes. Patients were divided into obese (body mass index ≥30 kg/m2) and nonobese (body mass index <30 kg/m2) cohorts using ICD-9 codes for body mass index and obesity. Complications within 90 days postoperatively were assessed using ICD-9 and Current Procedural Terminology (CPT) codes.
Results:
23,029 patients were identified from 2005 to 2011, including 5361 with TAA and 17,668 with AA. Obese TAA patients had a significantly increased risk of 90-day major, minor, local, systemic, venous thromboembolic, infectious, and medical complications compared with nonobese patients. The incidence of revision TAA was also significantly higher in obese patients compared with nonobese patients. Findings were similar for AA, as all types of complications were significantly higher in obese patients compared with nonobese patients.
Conclusion:
Obesity was associated with significantly increased rates of all complications after both TAA and AA. The cause of this association was likely multifactorial, including increased rates of medical comorbidities, intraoperative factors, and larger soft tissue envelopes.
Level of Evidence:
Level III, comparative series.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 871-880
Constantine A. Demetracopoulos, Samuel B. Adams, Robin M. Queen , [...]
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Abstract
Background:
Little is known about the efficacy and durability of total ankle arthroplasty (TAA) in younger patients. The purpose of this study was to determine the effect of age on the clinical, radiographic, and patient-reported outcomes of patients with end-stage ankle arthritis treated with TAA using modern prostheses.
Methods:
Patients who underwent primary TAA from June 2007 to July 2011 were prospectively enrolled in the study. Three hundred and ninety-five consecutive patients were reviewed with a mean follow-up of 3.5 years (range, 2-5.4 years). Patients were divided into 3 groups based on age at the time of surgery (<55, 55-70, and >70 years). Patient-reported outcome scores, physical performance scores, and weight-bearing radiographs were used to assess patients preoperatively and at yearly postoperative office visits. Revision was defined as failure of either the tibial or talar components requiring removal of the metallic implants. A repeated-measures analysis of variance with post hoc testing and the Pearson chi-square test were used to assess differences between the 3 groups. Statistical significance was set at an alpha level of .05.
Results:
Patients under the age of 55 had a greater improvement in Short-Form 36 (SF-36) Vitality (P = .026) and American Orthopaedic Foot & Ankle Society (AOFAS) Function scores (P < .001) compared with patients over the age of 70 at most recent follow-up. There were no differences in the Visual Analog Scale (VAS) pain score or the physical performance outcomes between the age groups. The incidence of wound complications, need for reoperation, and revision were not different between groups.
Conclusions:
Outcomes of TAA in younger patients were similar to outcomes in older patients at early follow-up. This study establishes a cohort of patients that will be followed to determine the effect of age on the long-term outcomes of TAA with an emphasis on the need for reoperation and revision.
Level of Evidence:
Level II, prospective comparative study.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 881-890
John S. Lewis, Cynthia L. Green, Samuel B. Adams , [...]
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Abstract
Background:
This series reviews the clinical and radiographic outcomes of patients who underwent total ankle replacement (TAR) using first- and second-generations of a modern fixed-bearing prosthesis utilizing a modular intramedullary stem.
Methods:
A consecutive series of first- and second-generation primary TARs with modular intramedullary stems were identified. Clinical outcome data were collected prospectively—including visual analog scale for pain, American Orthopaedic Foot & Ankle Society hindfoot-ankle, Short Musculoskeletal Function Assessment, and Short Form–36 scores. Preoperative coronal plane deformity and correction of deformity after TAR were assessed. Complications, subsequent procedures, and failure rates were compared. A total of 193 first- and 56 second-generation patients were identified with a mean follow-up of 3.7 and 2.1 years, respectively.
Results:
Clinical outcome data reflected significant improvements at 1 year postoperatively, and improvements were maintained at 2-year follow-up for each group. Improvement in visual analog scale scores were significantly better in the second-generation group at 1 year postoperatively, but this was not maintained at 2 years. Mean coronal tibiotalar angles for ankles with preoperative varus or valgus deformities were significantly improved. Correction was maintained until final follow-up, with no significant differences in deformity improvement between groups. The rate of reoperation at 2 years postoperatively on the affected foot or ankle subsequent to the index ankle replacement for patients in the first-generation group (18.5%) was higher compared to the second-generation group (15.9%), but the time until reoperation was not statistically significant (P = .376). The implant failure rate was higher in the first-generation group (6.0%) compared to the second-generation group (2.6%) at 2 years postoperatively, but the time until failure was not significantly different (P = .295).
Conclusion:
Patients who underwent TAR with a first- or second-generation fixed-bearing prosthesis with an intramedullary tibial component demonstrated significant improvements in all measures of pain and function with sustained improvements in coronal plane alignment. The second-generation prosthesis demonstrated slightly better improvements at 1 year and was associated with lower reoperation and implant failure rates.
Level of Evidence:
Level II, comparative series.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 891-900
Gökay Görmeli, Mustafa Karakaplan, Cemile Ayşe Görmeli , [...]
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Abstract
Background:
Osteochondral ankle injuries commonly affect the dome of the talus, and these injuries are a common cause of athletic disability. Various treatment options are available for these injuries including intra-articular hyaluronic acid (HA) and platelet-rich plasma (PRP) injections. The purpose of this study was to compare the effects of HA and PRP as adjunct therapies after arthroscopic microfracture in osteochondral lesions (OCLs) of the talus.
Methods:
In this prospective, randomized blinded study, 40 patients with talar OCLs in their ankle joints were treated with arthroscopic debridement and a microfracture technique. Thirteen randomly selected patients received PRP, 14 patients received HA, and the remaining 13 patients received saline as a control group. The participants were assessed using the American Orthopaedic Foot & Ankle Society (AOFAS) and visual analog pain scale (VAS) scores after a 15.3-month (range, 11-25 months) follow-up.
Results:
Postoperatively, all the groups exhibited significantly increased AOFAS scores and decreased VAS scores compared with their preoperative results (P < .005). The AOFAS scores were significantly increased in the PRP group versus the HA and control groups (P < .005), although the increased AOFAS scores in the HA group versus the control group were also significant (P < .005). Similar to the AOFAS scores, the decrease in the VAS scores was significantly lower in the PRP group versus the HA and control groups (P < .005). In addition, the HA group had significantly lower VAS scores than the control group (P < .005).
Conclusion:
Both PRP and HA injections improved the clinical outcomes of patients who underwent operation for talar OCLs in the midterm period and can be used as adjunct therapies for these patients. Because a single dose of PRP provided better results, we recommend PRP as the primary adjunct treatment option in the talar OCL postoperative period.
Level of Evidence:
Level I, prospective randomized study.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 901-907
Gowreeson Thevendran, Calvin Wang, Stephen J. Pinney , [...]
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Abstract
Background:
Nonunion risk factor identification and modification are subjective. We describe and validate a predictive nonunion risk factor model to identify foot and ankle operative patients at risk for nonunion.
Materials and Methods:
One hundred international experts in foot and ankle surgery were surveyed. Nineteen nonunion risk factors were stratified into 3 categories: more significant than, as significant as, and less significant than smoking 1 pack per day. A nonunion risk assessment model was developed by assigning a weighted score to each risk factor, based on its mean score from the survey. A total nonunion risk (TNR) score was calculated for individual patients. It was retrospectively validated in 2 patient cohorts from a single center’s prospectively collected end-stage ankle arthritis patient database: 22 cases of ankle and/or hindfoot fusion nonunion and 40 sex- and procedure-matched controls with bony fusion. Analyses included descriptive statistics, logistic regression, and univariate and multivariate linear regression models.
Results:
The mean TNR score was 6.6 ± 5.6 in controls and 13.5 ± 8.2 in the nonunion group (P < .001). Data showed excellent intraobserver and interobserver correlation coefficients. In a logistic regression model, the risk of nonunion exceeded 9% with a TNR score greater than or equal to 10. Multivariate linear regression analysis, adjusted for age and sex, suggested that lack of fusion site stability and obesity (body mass index greater than 30) were significantly predictive of nonunion.
Conclusion:
The nonunion risk assessment model provides a reliable, sensitive, and specific method for predicting nonunion based on objective patient assessment. Orthopaedic patients at risk for nonunion could benefit from targeted intervention.
Level of Evidence:
Level IV, retrospective observational study.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 908-918
Joint-preserving, realignment surgical procedures have gained increasing popularity as treatment of asymmetric early- and mid-stage ankle osteoarthritis. The aim of the present study was to quantify bilateral gait biomechanics in patients who underwent ankle realignment surgery by supramalleolar osteotomies.
Methods:
Eight patients, a minimum of 7 years after realignment surgery, and 8 healthy controls were included in this study. Three-dimensional instrumented gait analysis was used to assess spatiotemporal parameters, bilateral joint angles, and moments. Furthermore, a clinical evaluation on pain, ankle function, and quality of life was performed.
Results:
Compared with the healthy controls, the patients walked more slowly, had a smaller sagittal hindfoot range of motion on their affected leg, and had a lower peak ankle dorsiflexion moment (P < .05). There were no significant differences compared with controls for the ranges of motion in the foot segments of the nonaffected foot and for the knee and hip joint ranges of motion and peak moments of both legs. Additionally, patients and controls did not differ in the quality of life score. However, in the pain subscore, the patients reported significantly more pain than the healthy persons.
Conclusion:
Despite different gait biomechanics of the affected foot after ankle realignment surgery, the quality of life for patients was comparable to that of healthy controls. Therefore, supramalleolar osteotomies should be considered as a promising treatment option in patients with asymmetric non-end-stage ankle osteoarthritis.
Level of Evidence:
Level III, comparative study.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 919-927
Matthew S. Conti, Scott J. Ellis, Jeremy Y. Chan , [...]
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Abstract
Background:
While previous work has demonstrated a linear relationship between the amount of medializing calcaneal osteotomy (MCO) and the change in radiographic hindfoot alignment following reconstruction, an ideal postoperative hindfoot alignment has yet to be reported. The aim of this study was to identify an optimal postoperative hindfoot alignment by correlating radiographic alignment with patient outcomes.
Methods:
Fifty-five feet in 55 patients underwent flatfoot reconstruction for stage II adult-acquired flatfoot deformity (AAFD) by 2 fellowship-trained foot and ankle orthopedic surgeons. Hindfoot alignment was determined as previously described by Saltzman and el-Khoury.23 Changes in pre- and postoperative scores in each Foot and Ankle Outcome Score (FAOS) subscale were calculated for patients in postoperative hindfoot valgus (≥0 mm valgus, n = 18), mild varus (>0 to 5 mm varus, n = 17), and moderate varus (>5 mm varus, n = 20). Analysis of variance and post hoc Tukey’s tests were used to compare the change in FAOS results between these 3 groups.
Results:
At 22 months or more postoperatively, patients corrected to mild hindfoot varus showed a significantly greater improvement in the FAOS Pain subscale compared with patients in valgus (P = .04) and the Symptoms subscale compared with patients in moderate varus (P = .03). Although mild hindfoot varus did not differ significantly from moderate varus or valgus in the other subscales, mild hindfoot varus did not perform worse than these alignments in any FAOS subscale. No statistically significant correlations between intraoperative MCO slide distances and FAOS subscales were found.
Conclusions:
Our study indicates that correction of hindfoot alignment to between 0 and 5 mm of varus on the hindfoot alignment view (clinically a straight heel) following stage II flatfoot reconstruction was associated with the greatest improvement in clinical outcomes following hindfoot reconstruction in stage II AAFD.
Level of Evidence:
Level III, comparative series.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 928-935
Pain relating to degenerative joint disease within the foot and ankle can be difficult to localize with clinical examination alone due to the complex anatomy of the joints. The aim of this study was to determine whether single-photon emission computed tomography combined with conventional computed tomography (SPECT-CT) could be used to localize the site of degenerative joint disease for intra-articular injection and thereby improve the clinical success of the procedure.
Methods:
A prospective study was performed involving 203 patients who had undergone triple-phase 99mTc-hydroxymethylene diphosphonate bone scans with SPECT-CT of the foot and ankle for degenerative joint disease. Fifty-two patients went on to have joint injections for degenerative joint disease, with clinical follow-up. Correlation with the clinical diagnosis and the outcome of intra-articular injections with 0.5% bupivacaine and 80 mg of Depo-Medrone was performed. A successful outcome was determined by an improvement in the visual analog pain score of at least 50%.
Results:
In 19 (37%) patients, the site of degenerative joint disease determined by SPECT-CT differed from the initial clinical assessment and resulted in a change in management. Overall, 46 (88%) patients showed an improvement in symptoms.
Conclusion:
The study demonstrated a high clinical success rate for SPECT-CT-guided joint injections. The technique was useful in localizing degenerative joint disease of the ankle, hindfoot, and midfoot as an adjunct to clinical examination.
Level of Evidence:
Level IV, case series.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 936-943
Pamela C. Luk, Jeffrey E. Johnson, Jeremy J. McCormick , [...]
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Abstract
Background:
We present a technique of first metatarsophalangeal joint arthrodesis utilizing an interposition allograft bone block with a bipolar reaming technique that creates congruent fusion surfaces on both ends of the graft-host bone interface. In addition, we examined the union rates, fusion position, patient satisfaction, and functional outcome of this technique.
Methods:
Fifteen patients underwent first metatarsophalangeal joint arthrodesis with an interposition allograft bone block between September 2004 and October 2013. Charts and radiographs were reviewed. Six measures were compared on preoperative and postoperative radiographs. Clinical outcomes were measured using a telephone questionnaire, pre- and postoperative visual analog scale pain scale, and Foot and Ankle Ability Measure. Average follow-up was 46 weeks (range, 19 to 97).
Results:
Thirteen of 15 (87%) patients achieved bony union at an average of 21 weeks. One patient underwent revision arthrodesis for their nonunion. Symptomatic hardware was removed in 3 cases. Improvement was noted in visual analog scale pain scores (6 to 2) and functional scores as measured by the Foot and Ankle Ability Measure. There were no postoperative wound complications or infections. Average length of the first ray on anteroposterior radiograph increased from 10.7 to 11.3 cm and from 10.0 to 10.7 cm on the lateral radiograph. Thirteen of 14 patients were very satisfied or satisfied. One patient expressed dissatisfaction with the procedure. One patient was not available for clinical follow-up.
Conclusion:
First metatarsophalangeal joint allograft bone block arthrodesis using the bipolar reaming technique achieved high bony union rates and satisfactory radiographic and clinical outcomes. This procedure was an effective salvage option for managing bone loss on 1 or both sides of the joint.
Level of Evidence:
Level IV, retrospective case series.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 944-952
We aimed to find a new radiographic measurement for evaluating first metatarsal pronation and sesamoid position in hallux valgus (HV) deformity.
Methods:
Data from a clinical study of 19 control patients (19 feet) with no HV deformity were compared with preoperative data of 138 patients (166 feet) with HV deformities. Using a weightbearing plain radiograph in anteroposterior (AP) view, the intermetatarsal angles (IMAs) and the hallux valgus angles (HVAs) of the control and study groups were measured. Using a semi-weightbearing coronal computed tomography (CT) axial view, the α angle was measured in the control and study groups. In addition, the tibial sesamoid grades in plain radiograph tangential view and the CT axial view were measured. The tibial sesamoid position in an AP view was checked preoperatively. Based on these measurements, 4 types of HV deformities were defined.
Results:
The mean values of the α angle in the control and HV deformity groups (control group µ = 13.8 degrees, study group µ = 21.9 degrees) was significantly different. Among 166 HV feet, 145 feet (87.3%) had an α angle of more than 15.8 degrees, which is the upper value of the 95% confidence interval of the control group, indicating the existence of abnormal first metatarsal pronation in HV deformity. Four types of HV deformities were defined based on their α angles and tibial sesamoid grades in CT axial view (CT 4 position). Among 25.9% (43/166) of the study group, abnormal first metatarsal pronation with an absence of sesamoid deviation from its articular facet was observed. The prominent characteristic of this group was that they had high grades in the AP 7 position (≥5); however, in the CT 4 position, their grade was 0. This group was defined as the “pseudo-sesamoid subluxation” group.
Conclusions:
Patients with HV deformities had a more pronated first metatarsal than the control group, with a greater α angle. Pseudo-subluxation of the sesamoids existed in 25.9% of our study group. From our results, we suggest that the use of the CT axial view in assessments of HV deformity may benefit surgeons when they make operative choices to correct these deformities. With regard to the pseudo-sesamoid subluxation group, the use of the distal soft tissue procedure is not surgically recommended.
Level of Evidence:
Level III, retrospective comparative study.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 953-960
Christopher E. Gross, Jeannie Huh, Joni Gray , [...]
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Abstract
Background:
Lateral column lengthening (LCL) is commonly utilized in treating stage II posterior tibialis tendon dysfunction. This study aimed to analyze the outcomes of LCL with porous titanium wedges compared to historic controls of iliac crest autograft and allograft. We hypothesized that the use of a porous titanium wedge would have radiographic improvement and union rates similar to those with the use of autograft and allograft in LCL.
Methods:
Between May 2009 and May 2014, 28 feet in 26 patients were treated with LCL using a porous titanium wedge. Of the 26 patients, 9 were males (34.6%). The average age for males was 43 years (range, 17.9-58.7), 48.7 years (range, 21-72.3) for females. Mean follow-up was 14.6 months. Radiographs were examined for correction of the flatfoot deformity and forefoot abduction. All complications were noted.
Results:
Radiographically, the patients had a significant deformity correction in the anteroposterior talo-first metatarsal angle, talonavicular coverage angle, lateral talo-first metatarsal angle, and calcaneal pitch. All but 1 patient (96%) had bony incorporation of the porous titanium wedge. The average preoperative visual analog scale pain score was 5; all patients but 3 (12%) had improvements in their pain score, with a mean change of 3.4.
Conclusion:
LCL with porous titanium had low nonunion rates, improved radiographic correction, and pain relief.
Level of Evidence:
Level IV, case series.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 961-968
Alexis E. Dixon, Lydia C. Lee, Timothy P. Charlton , [...]
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Abstract
Background:
A previous study has shown an increased radiographic prevalence and severity of hallux valgus interphalangeus (HVIP) after surgical correction of hallux valgus (HV) due to correction of pronation deformity. The purpose of this study was to evaluate the change in pre- and postoperative HVIP deformity with correction of HV with multiple radiographic parameters.
Methods:
A retrospective chart review identified all bunion surgeries performed at a single center from July 1, 2009, to September 30, 2012. Exclusion criteria included prior bony surgery to the first ray, inadequate films, nonadult bunion, Akin osteotomy, or surgical treatment other than bunion correction. Pre- and postoperative films were reviewed for 2 HV angular measurements and 5 HVIP measurements, which were compared. The angles measured were hallux valgus angle (HVA), first intermetatarsal angle (IMA), hallux interphalangeus angle (HIA), distal metatarsal articular angle (DMAA), proximal phalangeal articular angle (PPAA), proximal to distal phalangeal articular angle (PDPAA), and total distal deformity (TDD). Prevalence of HVIP was analyzed in pre- and postoperative radiographs. A 1-sided Student t test was used to compare continuous data, and a chi-square test was used to compare categorical data. Ninety-two feet in 82 patients were eligible.
Results:
The average preoperative HV improved with surgery. Preoperative HVA improved from 27 to 11 degrees (P < .001). Preoperative IMA improved from 13.6 to 6.1 degrees (P < .001). HVIP worsened after surgery. Preoperative HIA increased from 7.2 to 13.2 degrees (P < .001). DMAA worsened from 7.3 to 9.2 degrees (P = .001). PPAA worsened from 3.2 to 6.2 degrees. PDPAA worsened from 6.7 to 8.2 degrees (P < .001). The TDD increased from 14.6 to 17.9 degrees (P < .001). The prevalence of HVIP pre- and postoperatively as defined by HIA increased from 26% to 79% (P < .001) and by PPAA from 12% to 46% (P < .001).
Conclusion:
Initial assessment of preoperative radiographs underestimated HVIP. Postoperative correction of the deformity revealed HVIP that was not obvious preoperatively.
Level of Evidence:
Level III, retrospective comparative series.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 969-975
Foot ulcers carry considerable morbidity in patients with peripheral neuropathy and frequently lead to foot amputation. The purpose of this study was to present our experience treating recalcitrant ulcers underlying the hallux interphalangeal joint in patients with diabetes mellitus (DM)–related neuropathy with a first metatarsophalangeal (MTPJ1) resection arthroplasty.
Methods:
We retrospectively reviewed the computerized medical files of patients with diabetic neuropathy treated with a MTPJ1 resection arthroplasty. We performed 28 arthroplasties on 20 patients with a mean age of 59 years. The patients had a diagnosis of DM for a mean of 10.7 years. Of the ulcers, 26 were grade 1A ulcers, and 2 were grade 2A ulcers (University of Texas score); the ulcer’s mean age was 5.4 months. The mean dorsiflexion of the hallux before surgery was 46 degrees.
Results:
The primary ulcer recovered in a mean of 3.1 weeks. Major complications (wound dehiscence and infection) occurred in 6 of 28 operations. Patients returned to normal activity 4 weeks after all procedures except in the 6 patients with dehiscence. In a subgroup of patients with follow-up longer than a year, the ulcer recurred after 4 of 18 arthroplasties (22%) between 3 and 12 months due to postoperative hallux rigidus. In the remaining 14 of 18 arthroplasties (78%), there was no recurrence during a mean follow-up of 26 months.
Conclusion:
MTPJ1 resection arthroplasty may be considered in a patient with resistant plantar hallux ulcerations, even in the absence of hallux rigidus. As with all operations on neuropathic feet in patients with DM, the surgeon and the patient should be aware that there is a significant likelihood of complications, but most are treatable.
Level of Evidence:
Level IV, case series.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 976-983
Mohammad Reza Abbasian, Felix Paradies, Martin Weber , [...]
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Abstract
Background:
Open rather than closed reduction and internal fixation as well as primary definitive arthrodesis are well accepted for ligamentous and osseous Lisfranc injuries. For ligamentous injuries, a better outcome after primary definitive partial arthrodesis has been published.
Methods:
Of 135 Lisfranc injuries that were treated from 1998 to 2012 with open reduction, temporary internal fixation by screws and plates, and restricted weight bearing in a lower leg cast for 3 months followed by an arch support for another 4 to 6 weeks, 29 ligamentous Lisfranc injuries were available for follow-up. They were compared with 29 osseous Lisfranc injuries matched in age and gender.
Results:
Between the groups, there were no significant differences in average age (39.9 vs 38 years) or in average follow-up time (8.3 vs 9.1 years). Also, no significant differences were seen in the AOFAS midfoot score (84 vs 85.3 points), the FFI pain scale (9.9 vs 14.9 points), SF 36 physical component (56.2 vs 53.9 points), SF 36 mental component (57 vs 56.4 points), or VAS for pain (1.6 vs 1.5 points). The FFI function scale was significantly lower in the ligamentous group (11.6 vs 19.5 points). Radiographically, loss of reduction was recorded 3 times in the ligamentous injuries and 4 times in the osseous injuries. Arthritis was mild/moderate/severe in 5/3/0 ligamentous injuries and in 7/2/1 osseous injuries, requiring 1 definitive secondary Lisfranc arthrodesis in each group.
Conclusion:
With longer and conservative postoperative management, open reduction and temporary internal fixation in ligamentous and osseous Lisfranc injuries led to equal medium-term outcome. Inferior outcome in ligamentous injuries was not found.
Level of Evidence:
Level III, retrospective comparative cohort study.
Research article
Restricted accessResearch articleFirst published August, 2015pp. 984-987