Single Medial vs 2-Incision Approach for Double Hindfoot Arthrodesis: Is There a Difference in Joint Preparation?

BACKGROUND: Double hindfoot arthrodesis is a reliable treatment option in lower extremity deformity and arthritis. Single (medial) and 2-incision techniques have been described. The purpose of this study was to evaluate the extent of cartilage debrided in each approach and to evaluate the competency of the deltoid ligament. METHODS: Eight matched pairs of cadaveric specimens were acquired. One limb from each pair was randomly assigned to the single medial incision and the other to the 2-incision technique. Stress radiographs were obtained prior to dissection to evaluate for valgus tibiotalar tilt. The talonavicular and subtalar articular surfaces were denuded of cartilage and the joints disarticulated. The percentage of cartilage debrided was determined using ImageJ software. Postoperative tibiotalar tilt was measured with a technique and threshold previously described by our group. The intraclass correlation coefficient was calculated to determine inter- and intraobserver reliability. RESULTS: The single medial incision demonstrated significantly less cartilage denuded than the 2-incision technique at the talar head (61.1% ± 20.4% vs 88.1% ± 6.1%, P < .001), and the posterior facets of the talus (53.5% ± 7.6% vs 73.6% ± 7.0%, P < .001) and calcaneus (55.3% ± 16.5% vs 81.0% ± 7.4%, P = .001). Overall, 75% of specimens that underwent a single medial incision approach demonstrated increased valgus tibiotalar tilt postdissection, whereas none that underwent the 2-incision technique developed increased tibiotalar tilt (P < .01). The average tibiotalar tilt among these specimens was 4.6 ± 1.3 degrees (range 2.5-5.7 degrees). For all measurements, the intraclass correlation coefficient was greater than 0.8. CONCLUSION: The posterior facet of the subtalar joint and talar head are at risk of subtotal debridement, as well as increased tibiotalar tilt with the single medial incision technique. Adequate debridement may require greater soft tissue dissection, possibly at the expense of medial ankle stability. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Peritalar Kinematics With Combined Deltoid-Spring Ligament Reconstruction in Simulated Advanced Adult Acquired Flatfoot Deformity.

BACKGROUND: Adult acquired flatfoot deformity (AAFD) is a complex and progressive deformity involving the ligamentous structures of the medial peritalar joints. Recent anatomic studies demonstrated that the spring and deltoid ligaments form a greater medial ligament complex, the tibiocalcaneonavicular ligament (TCNL), which provides medial stability to the talonavicular, subtalar, and tibiotalar joints. The aim of this study was to assess the biomechanical effect of a spring ligament tear on the peritalar stability. The secondary aim was to assess the effect of TCNL reconstruction in restoration of peritalar stability in comparison with other medial stabilization procedures, anatomic spring or deltoid ligament reconstructions, in a cadaveric flatfoot model. METHODS: Ten fresh-frozen cadaveric foot specimens were used. Reflective markers were mounted on the tibia, talus, navicular, calcaneus, and first metatarsal. Peritalar joint kinematics were captured by a multiple-camera motion capture system. Mild, moderate, and severe flatfoot models were created by sequential sectioning of medial capsuloligament complex followed by cyclic axial loading. Spring only, deltoid only, and combined deltoid-spring ligament (TCNL) reconstructions were performed. The relative kinematic changes were compared using 2-way analysis of variance (ANOVA). RESULTS: Compared with the initial condition, we noted significantly increased valgus alignment of the subtalar joint of 5.1 ± 2.3 degrees (P = .031) and 5.8 ± 2.7 degrees (P < .01) with increased size of the spring ligament tear to create moderate to severe flatfoot, respectively. We noted an increased tibiotalar valgus angle of 5.1 ± 2.0 degrees (P = .03) in the severe model. Although all medial ligament reconstruction methods were able to correct forefoot abduction, the TCNL reconstruction was able to correct both the subtalar and tibiotalar valgus deformity (P = .04 and P = .02, respectively). CONCLUSION: The TCNL complex provided stability to the talonavicular, subtalar, and tibiotalar joints. The combined deltoid-spring ligament (TCNL) reconstructions restored peritalar kinematics better than isolated spring or deltoid ligament reconstruction in the severe AAFD model. CLINICAL RELEVANCE: The combined deltoid-spring ligament (TCNL) reconstruction maybe considered in advanced AAFD with medial peritalar instability: stage IIB with a large spring ligament tear or stage IV.

Role of Patient-Reported Outcome Measures on Predicting Outcome of Bunion Surgery.

BACKGROUND: Prior studies have suggested preoperative patient-reported outcome scores could predict patients who would achieve a clinically meaningful improvement with hallux valgus surgery. Our goal was to determine bunionectomy-specific thresholds using Patient-Reported Outcomes Measurement Information System (PROMIS) values to predict patients who would or would not benefit from bunion surgery. METHODS: PROMIS physical function (PF), pain interference (PI), and depression assessments were prospectively collected. Forty-two patients were included in the study. Using preoperative and final follow-up visit scores, minimally clinically important differences (MCID), receiver operating characteristic (ROC) curves, and area under the curve (AUC) analyses were performed to determine if preoperative PROMIS scores predicted achieving MCID with 95% specificity or failing to achieve an MCID with 95% sensitivity. RESULTS: PROMIS PF demonstrated a significant AUC and likelihood ratio. The preoperative threshold score for failing to achieve MCID for PF was 49.6 with 95% sensitivity. The likelihood ratio was 0.14 (confidence interval, 0.02-0.94). The posttest probability of failure to achieve an MCID for PF was 94.1%. PI and depression AUCs were not significant, and thus thresholds were not determined. CONCLUSION: We identified a PF threshold of 49.6, which was nearly 1 standard deviation higher than previously published. If a patient is hoping to improve PF, a patient with a preoperative t score >49.6 may not benefit from surgery. This study also suggests the need for additional research to delineate procedure-specific thresholds. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

Deltoid-Spring Ligament Reconstruction in Adult Acquired Flatfoot Deformity With Medial Peritalar Instability.

BACKGROUND: A spring ligament tear is commonly present in advanced stages of adult acquired flatfoot deformity (AAFD). Previous anatomic studies have demonstrated that the superficial deltoid ligament blends with the superomedial spring ligament, forming the tibiocalcaneonavicular ligament (TCNL). Adding allograft TCNL reconstruction to osseous correction has been suggested to augment medial peritalar stability in advanced AAFD with large spring ligament tears. We aimed to investigate the clinical and radiographic outcomes of TCNL reconstruction for flexible AAFD with medial peritalar instability. METHODS: Fourteen feet in 12 patients who underwent osseous and TCNL reconstructions for advanced AAFD (stage IIB with large spring ligament tears or stage IV) were recruited for the study. The mean postoperative follow-up was 24 (range, 12-33) months. Pre- and postoperative clinical outcomes were assessed by the Foot and Ankle Ability Measure (FAAM), SF-36, and Patient-Reported Outcomes Measurement Information System (PROMIS). Correction of forefoot abduction and the sagittal arch were measured from pre- and postoperative weightbearing radiographs. RESULTS: The FAAM Activities of Daily Living improved from 69.3 to 90.1 (P = .001). The SF-36 Physical Function (PF) and Pain subscales both improved significantly (39.4 to 87.8 and 44.6 to 93.1, respectively, P < .001 for each). The PROMIS PF improved from 38.2 to 46.8 (P = .002) and the PROMIS Pain Interference (PI) from 62.6 to 50.1 (P = .003). Radiographic measures showed an improved anterior-posterior (AP) talo-first metatarsal angle of 24.7 to 11.8 degrees (P < .001) and talonavicular coverage angle of 47.4 to 23.1 degrees (P < .01). An improved Meary's angle of 29.7 to 12.5 degrees (P < .001) and a calcaneal pitch angle of 11.7 to 16.9 degrees (P = .14) were noted in the lateral view. CONCLUSION: Considering the anatomic characteristics of the deltoid-spring ligament complex, TCNL reconstruction may play a significant role in maintaining peritalar stability when performed with osseous correction. Deltoid-spring ligament (TCNL) reconstruction is a viable surgical option for those with advanced stage AAFD with medial peritalar instability that leads to improved functional and radiographic outcomes. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Evidence of differential microbiomes in healing versus non-healing diabetic foot ulcers prior to and following foot salvage therapy.

Diabetic foot ulcers (DFU) contribute to 80% of lower extremity amputations. Although physicians currently rely on clinical signs along with non-specific biomarkers of infection, such as erythrocyte sedimentation rate and C-reactive protein, to diagnose and monitor DFU, there is no specific and sensitive measure available to monitor or prognosticate the success of foot salvage therapy (FST). To address this we performed a prospective, observational microbiome analysis to test the hypotheses that: (i) the initial microbiomes of healed versus non-healed DFU are distinct; (ii) the microbial load, diversity and presence of pathogenic organism of the DFU change in response to antibiotics treatment; and (iii) the changes in the DFU microbiome during treatment are prognostic of clinical outcome. To test this, microbiome analyses were performed on 23 DFU patients undergoing FST, in which wound samples were collected at zero, four, and eight weeks following wound debridement and antibiotics treatment. Bacterial abundance was determined using quantitative polymerase chain reaction (qPCR). Eleven patients healed their DFU, while FDT failed to heal DFU in the other 12 patients. Microbiome results demonstrated that healing DFUs had a larger abundance Actinomycetales and Staphylococcaceae (p < 0.05), while DFUs that did not heal had a higher abundance of Bacteroidales and Streptococcaceae (p < 0.05). FST marked increases Actinomycetales in DFU, and this increase is significantly greater in patients that healed (p < 0.05). Future studies to confirm the differential microbiomes, and that increasing Actinomycetales is prognostic of successful FST are warranted. Statement of Clinical Significance: Tracking changes in the prevalence of pathogens in diabetic foot ulcers may be a clinical tool for monitoring treatment response to foot salvage therapy and prognosticating the need for further surgical intervention. The initial wound sample microbiome may provide important prognostic information on the eventual clinical outcome of foot salvage therapy. It may serve as an important clinical tool for patient counseling and making surgical decision of pursuing foot salvage versus amputation. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1596-1603, 2019.

Chronic Osteomyelitis with Staphylococcus aureus Deformation in Submicron Canaliculi of Osteocytes: A Case Report.

CASE: A patient presenting with an infected diabetic foot ulcer and Staphylococcus aureus chronic osteomyelitis was studied to validate the clinical importance of bacterial colonization of osteocytic-canalicular networks, as we recently reported in a mouse model. We utilized transmission electron microscopy to describe the deformation of S. aureus, from round cocci to rod-shaped bacteria, in the submicron osteocytic-canalicular networks of amputated bone tissue. CONCLUSION: To our knowledge, this is the first evidence of S. aureus deformation and invasion of the osteocytic-canalicular system in human bone, which supports a new mechanism of persistence in the pathogenesis of chronic osteomyelitis.