Minimally Invasive Surgery vs Nonoperative Treatment for Displaced Intraarticular Calcaneal Fracture: A Prospective Propensity Score Matched Cohort Study With 2-Year Follow-up

BACKGROUND

Optimal management of displaced intraarticular calcaneal fractures remains controversial. The aim of this prospective cohort study was to compare the clinical and radiologic outcomes of minimally invasive surgery vs nonoperative treatment in displaced intraarticular calcaneal fracture up to 2 years.

METHODS

All displaced intraarticular calcaneal fractures between August 2014 and January 2019 that presented to a level 1 trauma center were considered for inclusion. The decision to treat was made by a multidisciplinary team consisting of fellowship-trained orthopaedic surgeons. Operative treatment protocol involved sinus tarsi approach or percutaneous reduction and internal fixation. Nonoperative protocol involved symptomatic management with no attempt at closed reduction. The Manchester-Oxford Foot Questionnaire (MOXFQ) and EuroQol-5 Dimensions-5 Level (EQ-5D-5L) patient-reported outcome measures were used to assess foot and ankle and general health related quality of life outcomes, respectively, at 2-year follow-up. Radiographic assessment was performed based on preinjury and 12-week postinjury radiographs.

RESULTS

A total of 101 patients were included for analysis between August 2014 and January 2019. We propensity score matched 46 patients in the surgical cohort to 46 patients in the nonsurgical cohort. At 24 months, there was no significant difference in the MOXFQ Index score (P > .05); however, the surgical cohort had a significantly higher EQ-5D-5L Index score (P < .05) and return to work (91% vs 72%, P < .05) and physical activity rate (46 vs 35%, P < .05) despite a higher proportion of more complex fractures in the surgical cohort. The wound complication rate following surgery was 16%. In addition, 14% of patients in the nonoperative cohort subsequently underwent arthrodesis compared with none of the patients in the surgical cohort.

CONCLUSION

In this study, we found that operative treatments were associated with low rates of surgical complication at 2 years and long-term pain improvement, facilitating earlier and better functional outcomes for complex injury patterns compared with nonoperative treatment for less severe fractures.

LEVEL OF EVIDENCE

Level III, retrospective cohort.

Sinus Tarsi Versus Extended Lateral Approach for Displaced Intra-Articular Calcaneal Fractures: A Single Surgeon's Experience

BACKGROUND

The aim of the study is to investigate the differences between the extensile lateral (EL) and sinus tarsi (ST) approaches for the treatment of displaced intra-articular calcaneus fractures as treated by a single surgeon.

METHODS

A retrospective cohort study performed at a Level 1 trauma center. One hundred twenty-nine consecutive intra-articular calcaneus fractures from 2011 to 2018 that were surgically treated by a single surgeon. Primary outcomes were time to surgery, operative time, postoperative restoration of the critical angle of Gissane, postoperative wound complications, and need for unplanned re-operation.

RESULTS

Patient characteristics, including demographics, mechanism of injury, and fracture patterns were similar between the EL and ST approach groups. There was a significant decrease in unplanned secondary procedures (P = .008), shorter time to definitive fixation (P = .00001), and shorter average operative time in the ST group (P = .00001). Postoperative measurement of the critical angle of Gissane between the two groups was significantly different, but minute with an average difference of approximately 3 degrees (P = .025). Measurements in both groups were within the expected range of normal.

CONCLUSIONS

For displaced intra-articular calcaneus fractures, a limited open ST approach is associated with a significant reduction in the time to definitive fixation and decreased operative time. The EL approach was associated with a small, but significant improvement in the restoration of the critical angle of Gissane compared with the ST approach. Therefore, an ST approach may allow for earlier surgical intervention and result in equivalent quality of reduction compared with an EL approach.

LEVEL OF EVIDENCE

Level III.

A retrospective magnetic resonance imaging analysis of bone and soft tissue changes associated with the spectrum of tarsal coalitions

We aimed to investigate the bone and soft tissue changes accompanying tarsal coalition (TC) and aimed to evaluate their association with the location and type of coalition. Ankle magnetic resonance imagings of 65 patients with TC were included. The relationship between the location and type of coalition and bone marrow edema, subchondral cysts, sinus tarsi syndrome, tarsal tunnel syndrome, posterior impingement syndrome, accessory bone, tibiotalar effusion, talar osteochondritis dissecans, ganglion cysts, and calcaneal spur were evaluated. Twenty-nine patients without coalition were selected as the control group, and the distribution of these variables between the two groups was analyzed. There were 33 females and 32 males in the coalition group (mean age: 42.0 ± 15.63 years), and 22 females and seven males in the control group (mean age: 44.79 ± 12.33 years). Coalition was most common in the talocalcaneal joint (n = 33, 50.8%), and the most common coalition type was non-osseous (n = 57, 87.6%). We find no significant difference between the pathologies defined in terms of coalition location and type. Sinus tarsi syndrome, tarsal tunnel syndrome, subchondral cysts, and tibiotalar effusion were found to be more common in the coalition group (p = 0.028, p = 0.010, p = 0.023, and p = 0.006, respectively). The presence of coalition increased the probability of developing tarsal tunnel syndrome 9.91 times (95% CI: [1.25-78.59]; p = 0.029), and sinus tarsi syndrome 3.66 times (95% CI: [1.14-11.78]; p = 0.029). Tarsal coalition may predispose bone and soft tissue changes. In this study, sinus tarsi syndrome, tarsal tunnel syndrome, subchondral cysts and tibiotalar effusion were found to be more common in the coalition group.

Radiographic Cutoff Values for Predicting Lateral Bony Impingement in Progressive Collapsing Foot Deformity

BACKGROUND

Lateral bony impingement is a major cause of lateral foot pain in progressive collapsing foot deformity (PCFD). Weightbearing computed tomography (WBCT) provides better sensitivity than standard radiographs for detecting impingement. However, many orthopaedic centers have not yet acquired WBCT imaging. This study aimed to (1) investigate the correlation of common radiographic parameters measured on standard weightbearing radiographs with talocalcaneal and calcaneofibular distance assessed with WBCT and (2) establish radiographic cutoff values to detect bony impingement as identified on WBCT.

METHODS

Ninety-one patients treated for PCFD with standard preoperative radiographs and WBCT were identified. Patients with asymmetric ankle arthritis (talar tilt >2 degrees) were excluded. The talocalcaneal distance at the sinus tarsi and calcaneofibular distance were measured in multiplanar reconstructed WBCT images. Impingement was defined as direct abutment between bones. The relationships between WBCT measurements and 4 common parameters (talonavicular coverage angle [TNC], talo-first metatarsal angle, calcaneal pitch, and hindfoot moment arm [HMA]) in standard radiographs were assessed with Pearson correlations. Receiver operating characteristic curve analysis evaluated the ability of radiographic cutoffs to detect sinus tarsi or calcaneofibular bony impingement, and the area under curve (AUC), sensitivity, specificity, negative and positive predictive value (PPV) were calculated.

RESULTS

Talocalcaneal distance narrowing at the sinus tarsi strongly correlated with TNC (r = 0.64, P < .001), and the calcaneofibular distance narrowing correlated with the HMA moderately yet best among the parameters (r = 0.55, P < .001). TNC (AUC = 0.837, 95% CI 0.745-0.906) and HMA (AUC=0.959, 95% CI 0.895-0.989) provided the best predictive ability for sinus tarsi and calcaneofibular bony impingement, respectively. A TNC threshold of 41.2 degrees had a 100% PPV for predicting sinus tarsi impingement, whereas an HMA threshold of 38.1 mm had a 100% PPV for calcaneofibular impingement.

CONCLUSION

This study provides evidence that TNC and HMA measurements made on standing radiographs could be used to indicate potential lateral bony impingement in PCFD. Narrowing of talocalcaneal distance best correlated with abduction deformity of the foot, and the narrowing of calcaneofibular distance was best correlated with valgus hindfoot deformity.

LEVEL OF EVIDENCE

Level III, case control study.

An Anatomic Study of the Sural Nerve Using 3-Tesla MRI: A Comparison to Cadaveric Data With Surgical Applications

BACKGROUND

The sural nerve (SN) is a sensory cutaneous nerve that is at risk of iatrogenic injury during surgery at the lateral ankle. Prior anatomic studies of the SN are limited primarily to cadaveric studies with small sample sizes. Our study analyzed a large cohort of magnetic resonance images (MRIs) of the ankle to obtain a more generalizable, in vivo sample of distal SN course.

METHODS

A total of 204 3-tesla MRI studies of the ankle were analyzed. Three reviewers measured the distance from the SN to various landmarks including the distal tip of the lateral malleolus (DTLM) and the lateral border of the Achilles tendon (LBA).

RESULTS

Mean vertical distance from SN to DTLM was 2.2 cm (range, 0.9-3.6 cm). Mean horizontal distance from SN to DTLM and to LBA at the level of DTLM was 1.7 cm (range, 0.8-3.0 cm) and 1.9 cm (range, 1.0-2.9 cm), respectively. Mean horizontal distance from SN to LBA at the level of superior Achilles tendon insertion onto the calcaneus (SAI) was 2.6 cm (range, 1.4-3.7 cm), and mean horizontal distance from SN to LBA at 5 cm above SAI was 0.9 cm (range, 0.4-1.8 cm).

CONCLUSION

The variation in SN course observed in our study allowed us to propose "safe zones" for several surgical approaches including the extensile lateral approach to the calcaneus (ELAC), the sinus tarsi approach (STA), the direct lateral approach to the lateral malleolus (DLA), and the posterolateral approach to the ankle (PLA), which we hope will minimize iatrogenic injury to the SN.

LEVEL OF EVIDENCE

Level IV, case series.

Accessory Talar Facet Impingement and Sinus Tarsi Pain Associated With Accessory Anterolateral Talar Facet

BACKGROUND

Sinus tarsi pain caused by accessory talar facet impingement (ATFI) owing to accessory anterolateral talar facet (AALTF) is not well documented. We evaluated prevalence of AALTF and differences of magnetic resonance imaging (MRI) findings between persons with and without sinus tarsi pain, and investigated the relevant association between MRI findings and sinus tarsi pain in persons with AALTF.

METHODS

We performed a case-control study on 120 ankles with sinus tarsi pain and 120 age- and gender-matched ankles without sinus tarsi pain. As MRI findings, bone marrow edema (BME), sinus tarsi fat obliteration (STFO), calcaneal cyst, talocalcaneal coalition, Gissane angle, talar inferolateral surface (TILS) angle, and calcaneal cortical thickness (CCT) were evaluated. The MRI findings were compared between persons with and without sinus tarsi pain, and between persons with and without AALTF. Among persons with AALTF, MRI findings were compared between those with and without sinus tarsi pain. Relevant association was evaluated between MRI findings and sinus tarsi pain in persons with AALTF.

RESULTS

Presence of AALTF, BME, and STFO were significantly higher in the group with sinus tarsi pain. The Gissane angle was significantly smaller, and the TILS angle and CCT were significantly larger in the group with sinus tarsi pain. The BME (OR 7.571, CI 1.453-39.446) and small Gissane angle (OR 0.891, CI 0.804-0.986) were significantly associated with sinus tarsi pain in persons with the AALTF.

CONCLUSION

The study provides evidence for ATFI related to impingement of an AALTF associated with talocalcaneal BME.

LEVEL OF EVIDENCE

Level III, case-control study.

Minimally invasive approach with external fixator for intra-articular calcaneal fractures in children

Calcaneal fractures are rare in pediatric population, with more displaced intra-articular fractures encountered due to the increasing number of high-energy trauma. Operative interventions are gaining popularity because of the unsatisfactory outcomes of traditional conservative methods. This study investigated the clinical outcomes of a minimally invasive technique using the sinus tarsi approach and external fixator in the treatment of intra-articular calcaneal fractures in pediatric patients.Patients who underwent open reduction between January 2010 and January 2018 at our institute were included in this study and reviewed retrospectively. Radiological and clinical parameters were all recorded and analyzed.Overall, 29 patients were included in the study, including 23 boys and 6 girls (10.2 ± 2.2 years old). The average follow-up was 29.5 months postoperatively (range, 26-72 months). Bohler angle was 15.2 ± 3.3° preoperatively, and 34.0 ± 3.8° postoperatively (P < .001); Gissane angle was 101.8 ± 6.2 degrees preoperatively, and 129.7 ± 6.2° postoperatively (P < .001). The average length of incision was 3.4 ± 0.7 cm. At the last follow-up, all patients showed satisfactory clinical outcomes and the score was 90.0 ± 2.3 according to American Orthopedic Foot and Ankle Society Scale.Minimally invasive approach with external fixator is an effective method for treating displaced intra-articular calcaneal fractures in pediatric patients, with a lower incidence of wound-related complications and good cosmetic outcomes.

Mini-plate fixation via sinus tarsi approach is superior to cannulated screw in intra-articular calcaneal fractures: A prospective randomized study

OBJECTIVE

Intra-articular displaced calcaneal fractures are common fractures and are often treated with surgical interventions. Sinüs tarsi approach provides secure access to lateral wall and joint facets. The aim of the study is to compare cannulated screw (CS) fixation and mini-plate (MP) fixation via sinus tarsi approach with Sanders types 2 and 3 fracture of calcaneus.

METHODS

Sixty patients with Sanders types 2 and 3 calcaneal fracture underwent surgical intervention were randomly allocated into two groups as group MP fixation and group CS fixation regarding osteosynthesis method for 5-year period. Open reduction via sinüs tarsi approach was performed in both groups. Demographic variables, time to surgery (TS), operation duration (OD), length of hospital stay (LOS), surgical complications, and reoperations were recorded. Pre- and postoperative Gissane and Böhler angles; calcaneal length, height, and width; ankle anterior-posterior (AP) and lateral X-rays; and computed tomography were also recorded for radiological evaluation and fracture characteristics. Maryland Foot Score (MFS) was used to evaluate functional outcomes.

RESULTS

Preoperative age, type of fracture, calcaneal length, height, and Gissane and Böhler angles, TS, LOS, and OD were not different between the groups. The postoperative calcaneal widening was significantly better restored in group MP compared with that of group CS. The incidence of reoperation and algoneurodystrophy was statistically higher in group CS than group MP. MFS in group MP was also higher than group CS at final visit.

CONCLUSION

MP fixation via sinus tarsi approach is superior to CS fixation in Sanders types 2 and 3 calcaneal fractures.

Radiographic and Postoperative Outcomes of Plate Versus Screw Constructs in Open Reduction and Internal Fixation of Calcaneus Fractures via the Sinus Tarsi

BACKGROUND

Intra-articular fractures of the calcaneus are a common injury to the hindfoot following high-energy trauma to the lower extremity. Treatment of these fractures has evolved. Due to the concern of wound complications associated with extensile open treatment, smaller incision techniques, such as the sinus tarsi approach, are increasing in popularity. A number of fixation strategies are utilized with this approach, and it is unknown which most accurately restores radiographic alignment. The purpose of this study was to compare the postoperative radiographic outcomes of a plate and screw construct versus a cannulated screw construct when using the sinus tarsi approach for open reduction and internal fixation (ORIF) of calcaneus fractures.

METHODS

After institutional review board approval, records for all patients treated surgically at our institution for calcaneus fractures from 2012 to 2017 were reviewed. Inclusion criteria were intra-articular calcaneus fractures, patients aged 18 years or older, and use of the sinus tarsi approach. Exclusion criteria were open fractures and fractures with less than 6 weeks of postoperative weightbearing, which were excluded for radiographic outcomes. A total of 51 fractures underwent ORIF using cannulated screws alone (group 1), and 23 fractures underwent ORIF using a sinus tarsi plate (group 2). Sixty-one fractures (41 vs 20, respectively) met criteria for radiographic comparison. The primary outcomes of interest included pre- and postoperative Bohler and Gissane angles, wound complications, unplanned return to the operating room (OR), and cost comparison.

RESULTS

There was no statistically significant difference between preoperative Bohler angles for group 1 (14.4 degrees) versus group 2 (12.2 degrees) (P = .44), nor was there a significant difference between postoperative Bohler angles for group 1 (30.1 degrees) versus group 2 (27.1 degrees) (P = .14). Similarly, preoperative Gissane angles for group 1 (130.5 degrees) and group 2 (133.4 degrees) (P = .54) and postoperative Gissane angles for group 1 (118.2 degrees) and group 2 (119.8 degrees) (P = .44) showed no statistically significant difference. There were a total of 3 wound complications in group 1 versus 2 wound complications in group 2 (P = .66). There was no statistically significant difference in operative duration (P = .97) or the number of unplanned returns to the OR between the 2 groups (P = .68). Based on the implants used at this institution, and depending on the number of screws used, the estimated cost range of a plate construct was $1070 to $1235, while the estimated cost range of a cannulated screw construct was $717 to $1264.

CONCLUSION

When comparing the cannulated screw and plate and screw fixation techniques, there was no difference in restoration of the Bohler and Gissane angles. Furthermore, the amount of angular correction achieved by initial reduction showed no statistically significant difference between groups, and the amount of reduction lost between initial and final postoperative radiographs showed no statistically significant difference between groups. With regard to the 2 techniques, there was no statistically significant difference in rates of postoperative complications and return to the OR. Our data suggest that fixation using cannulated screws alone versus sinus tarsi plate provides similar radiographic outcomes and risk of complications. The 2 techniques were also similar in terms of implant costs. Our results indicate that either technique effectively improved radiographic parameters.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Gouty Tophi in Sinus Tarsi of Bilateral Feet Mimicking Synovial Sarcoma:A Case Report

Chronic gout is defined as accumulation of monosodium urate crystals in joints, cartilage, tendons, bursae, bone, and soft tissue. The foot is the most common location for acute gout flares, with the first metatarsophalangeal joint being the most frequent site of tophus formation. However, few studies have reported gouty tophus formation in the subtalar joint. Gout has been termed the "great mimicker" because of its tendency to mimic other pathologic conditions, such as pigmented villonodular synovitis and synovial sarcoma. Herein, we present a rare case of chronic tophaceous gout in the sinus tarsi in both feet in a 23-year-old healthy male, with extensive bony erosions mimicking pigmented villonodular synovitis and synovial sarcoma. We discuss the clinical presentation, distinguishing radiologic characteristics, surgical procedures, and outcome regarding this unique presentation.

Endoscopic Approach for the Excision of Giant Cell Tumor of Tendon Sheath Involving the Hindfoot: A Case Report

Giant cell tumor of tendon sheath (GCT-TS) is an often benign neoplasm that is relatively uncommon in the foot and ankle when compared to the upper extremities. Magnetic resonance imaging aids in characterizing the lesion, but diagnosis is confirmed with biopsy. Surgical excision is the preferred treatment. There is a lack of studies examining the long-term outcomes of endoscopic excision of GCT-TS, especially lesions found in the foot and ankle. The present study describes a case of a 42-year-old male with GCT-TS of the hindfoot treated with an endoscopic excision through a sinus tarsi approach. The patient was asymptomatic with no local signs of recurrence at the 67-month follow-up visit.

Extended Sinus Tarsi Approach for Treatment of Displaced Intraarticular Calcaneal Fractures Compared to Extended Lateral Approach

BACKGROUND:

We compared the radiographic results and clinical outcomes of patients operated on via the extended sinus tarsi approach (ESTA) and the extended lateral approach (ELA) for treatment of displaced intraarticular calcaneal fractures.

METHODS:

We retrospectively studied the utility of the ELA (46 patients, 52 feet) and the ESTA (56 patients, 64 feet) in patients operated on between January 2009 and March 2015. We evaluated pre- and postoperative x-rays and computed tomography (CT) data. Pain, patient-reported functional outcomes, satisfaction, and postoperative complications were investigated at the 3-year follow-up.

RESULTS:

Neither the postoperative nor 3-year follow-up Böhler angles, nor the calcaneal width, differed significantly between the 2 groups (both P > .05). However, the maximum step-off of the posterior facet on the 3-month CT follow-up of the ESTA group was significantly less than that of the ELA group ( P < .05). We found no significant between-group differences in terms of postoperative translation ( P = .232) or angulation ( P = .132) of the sustentacular fragment on the 3-month CT follow-up. At the 3-year follow-up, we found no significant between-group difference in the mean visual analog scale pain score at rest ( P = .641) or during weightbearing ( P = .525). We found no significant between-group difference in the Foot Function Index (FFI) ( P = .712) or self-reported satisfaction ( P = .823). The ELA group experienced significantly more wound complications ( P = .041) and nonunions ( P = .041) than the ESTA group. Four instances of superficial peroneal nerve injury were reported in the ESTA group ( P = .127).

CONCLUSION:

Compared with the ELA, the ESTA afforded comparable, favorable radiological results and clinical outcomes, associated with fewer wound complications and nonunions. We suggest that the ESTA is an effective operative option when treating displaced, intraarticular calcaneal fractures.

LEVEL OF EVIDENCE:

Level III, comparative study.

Assessment of Bony Subfibular Impingement in Flatfoot Patients Using Weight-Bearing CT Scans

BACKGROUND:

Lateral hindfoot pain in patients with flatfoot deformity is frequently attributed to subfibular impingement. It remains unclear whether this is primarily due to bony or soft-tissue impingement. No studies have used weight-bearing CT scans to evaluate subfibular impingement.

METHODS:

Patients with posterior tibial tendonitis were retrospectively searched and reviewed. Subjects had documented flatfoot deformity, posterior tibial tenderness, weight-bearing plain radiographs, and a weight-bearing CT scan. CT scans were evaluated for calcaneofibular impingement on the coronal view and talocalcaneal impingement on the sagittal view. The distance between these structures was measured, along with the sinus tarsi volume. In the second part of this study, 6 normal volunteers underwent weight-bearing CT scans on a platform that held both feet in 20 degrees of varus, followed by 20 degrees of valgus. The same measurements were performed.

RESULTS:

Thirty-five percent of flatfoot patients with posterior tibial tendonitis had bony impingement between the fibula and calcaneus on the coronal view. Thirty-eight percent had bony impingement between the talus and calcaneus on the sagittal view. Subjects with bony impingement based on CT scan had significantly higher talonavicular abduction angles on plain radiographs than those without impingement. Sinus tarsi volume decreased by more than half when the subtalar joint moved from varus to valgus in normal controls.

CONCLUSION:

Bony subfibular impingement in patients with flatfeet was less common than previously reported. Accurate diagnosis of bony impingement may be useful for surgical decision-making.

LEVEL OF EVIDENCE:

Level III, retrospective comparative study.

Comparison of Calcaneal Exposure Through the Extensile Lateral and Sinus Tarsi Approaches

The purpose of this study was to compare the exposure of the posterior facet with the extensile lateral (EL) approach compared with the sinus tarsi (ST) approach. We hypothesized that the ST approach will provide a similar exposure of the posterior calcaneal facet. A total of 8 sequential ST then EL approaches were performed on cadavers. Calcaneal landmarks were identified by visualization or palpation. Calibrated digital photographs of the posterior facet and lateral calcaneal body were obtained from standardized positions and used to calculate the exposed surface area. No significant difference was found in the average square area of the posterior facet exposed with the 2 approaches. Significantly more of the lateral calcaneal body was seen with the EL approach. Excluding the posterior facet superomedial quadrant, all the landmarks were visualized in 100% of approaches. The superomedial corner was visualized in significantly more of the cadavers with the EL approach and was palpable in 12.5% of the remaining cadavers in both approaches. Whereas the ST approach exposes less of the lateral wall of the calcaneus, it exposes similar amounts of the posterior facet when compared with the EL approach.

LEVELS OF EVIDENCE

Therapeutic, Level V.

Radiographic and CT Assessment of Reduction of Calcaneus Fractures Using a Limited Sinus Tarsi Incision

BACKGROUND

The lateral extensile incision for fixation of displaced intra-articular calcaneus fractures allows for fracture reduction but has been associated with high rates of soft tissue complications. This has prompted a search for less invasive methods of fracture fixation. The purpose of the present study was to determine the adequacy of reduction and rate of complications associated with operative fixation of calcaneal fractures using a limited sinus tarsi approach.

METHODS

A limited sinus tarsi incision with plate fixation was utilized for treatment of 39 displaced intra-articular calcaneal fractures in 35 consecutive patients as part of a single surgeon series. Imaging assessment of previously described fracture displacement measures was undertaken in preoperative and postoperative radiographs and CT. A retrospective chart review was conducted to identify postoperative complications.

RESULTS

Mean preoperative Bohler angle measurement was 7.7 (range, -26.0 to 30.0) degrees and the mean final postoperative standing Bohler angle was 25.5 (range, 12.3 to 37.7) degrees. Postoperative CT demonstrated that subtalar articular reduction was within 2 mm of anatomic in 91% of patients. There were 2 instances of superficial wound dehiscence (5.1%) and 1 deep infection (2.6%) that required debridement and complete hardware removal. Visual analog score (VAS) for pain averaged 3 of 10 in the 32 available patients at 1-year follow-up. Eight of these patients (25%) reported no pain (0/10) at final follow-up.

CONCLUSION

Operative fixation of displaced intra-articular calcaneal fractures utilizing the limited sinus tarsi approach resulted in acceptable fracture reduction and a low rate of complications.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Accessory Anterolateral Talar Facet in Populations With and Without Symptoms: Prevalence and Relevant Associated Ankle MRI Findings

OBJECTIVE

The purpose of this study was to determine the prevalence of and relevant findings associated with the accessory anterolateral talar facet, which may have a role in talocalcaneal impingement and sinus tarsi syndrome, on ankle MR images of persons with and those without symptoms.

SUBJECTS AND METHODS

In this case-control study, three observers independently reviewed 1.5-T or 3-T MR images of 110 ankles with symptoms in 100 consecutively registered patients (age range, 16-79 years; mean, 41.5 years) and limited 1.5-T MR images of 104 age-, sex-, and side-matched ankles in 104 volunteers without symptoms for the presence of an accessory anterolateral talar facet, calcaneal cortical thickness, subjacent talar or calcaneal cystic and bone marrow edema-like changes at the angle of Gissane, and sinus tarsi fat obliteration.

RESULTS

An accessory anterolateral talar facet was present in 36 (32.7%) ankles with symptoms versus 27 (26.0%) symptom-free ankles (p = 0.297). Interobserver agreement was almost perfect (κ = 0.851; 95% CI, 0.772-0.929) for the detection of accessory anterolateral talar facet and substantial for the detection of sinus tarsi fat obliteration (κ = 0.671; 95% CI, 0.427-0.915). The angle of Gissane was significantly smaller in persons with an accessory anterolateral talar facet, either with or without symptoms (p < 0.0001). Subjacent talar (p = 0.003) and calcaneal (p = 0.033) bone marrow edema-like change and sinus tarsi fat obliteration (p = 0.034) were significantly more frequent in persons with accessory anterolateral talar facet, but chronic reactive osseous changes at the angle of Gissane were not (p > 0.05).

CONCLUSION

The higher prevalence of the MRI finding of an accessory anterolateral talar facet in ankles with symptoms is not statistically significant. This facet may be associated with subjacent talar bone marrow edema-like change on MR images of individuals with and those without symptoms and with sinus tarsi fat obliteration in individuals with symptoms.

Treatment of Stage II Adult Acquired Flatfoot Deformity With Subtalar Arthroereises

The role of arthroereises in the treatment of adult acquired flatfoot deformity (AAFD) has been controversial. This study aims to evaluate the outcome of subtalar arthroereisis in treating stage II AAFD. A total of 24 feet with stage II AAFD were treated surgically between 2009 and 2011 using subtalar arthroereisis. The average follow-up was 29.7 months (range = 24 to 35 months). The average postoperative AOFAS (American Orthopaedic Foot and Ankle Society) Ankle-Hindfoot Scale score was 85.6 (compared with 51.7 preoperatively). Average preoperative talar-first metatarsal angle and talonavicular coverage angle were -13.9° and 38.3°, respectively. The average postoperative angles were 1.6° and 11.2°, respectively (P < .01). No deformity recurrences were found at the time of last follow-up, with the exception of 1 case. Subtalar arthroereisis appears to be a reasonable treatment option for stage IIA and IIC AAFD. It can be used alone to correct mild hindfoot valgus, and it can also be performed with a calcaneal osteotomy to gain more correction in severe stage II AAFD.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Retrospective Case Series.

Sonographically guided posterior subtalar joint injections via the sinus tarsi approach

OBJECTIVES

To determine the feasibility and accuracy of sonographically guided posterior subtalar joint (PSTJ) injections performed through the sinus tarsi.

METHODS

A single experienced operator completed 10 sonographically guided PSTJ injections via the sinus tarsi on 10 unembalmed cadaveric ankle-foot specimens. Injections were performed using a 17-5-MHz linear transducer, a 25-gauge, 50-mm needle, and an out-of-plane, anterior-to-posterior needle trajectory parallel to the calcaneal surface. Sonographic assessment for fluid in the posterior and lateral PSTJ recesses, sinus tarsi, and peroneal tendon sheath was performed before and after injections of 2 and 4 mL of tap water. Two additional specimens were injected with a contrast agent: 1 via the sonographically guided approach and another by a computed tomographically guided approach.

RESULTS

All 10 sonographically guided PSTJ tap water injections were accurate, distending both the posterior and lateral PSTJ recesses. In addition, all 10 specimens showed posterior recess distension by 2 mL, whereas only 2 specimens (20%) showed lateral recess distension at this volume. By 4 mL, both recesses were clearly distended in all specimens. Both contrast agent injections produced similar PSTJ computed tomographic arthrograms and patterns of recess distension similar to the sonographically guided tap water injections. No sonographically guided PSTJ injection placed fluid in the peroneal tendon sheath.

CONCLUSIONS

Sonographically guided PSTJ injections via the sinus tarsi can accurately and specifically deliver injectate into the PSTJ while monitoring injectate flow within the posterior recess. The sinus tarsi approach may be used as an alternative technique to perform sonographically guided PSTJ injections when clinically appropriate.

Distribution of sensory nerve endings around the human sinus tarsi: a cadaver study

The aim of this study was to analyse the pattern of sensory nerve endings and blood vessels around the sinus tarsi. The superficial and deep parts of the fat pads at the inferior extensor retinaculum (IER) as well as the subtalar joint capsule inside the sinus tarsi from 13 cadaver feet were dissected. The distribution of the sensory nerve endings and blood vessels were analysed in the resected specimens as the number per cm(2) after staining with haematoxylin-eosin, S100 protein, low-affinity neurotrophin receptor p75, and protein gene product 9.5 using the classification of Freeman and Wyke. Free nerve endings were the predominant sensory ending (P < 0.001). Ruffini and Golgi-like endings were rarely found and no Pacini corpuscles were seen. Significantly more free nerve endings (P < 0.001) and blood vessels (P = 0.01) were observed in the subtalar joint capsule than in the superficial part of the fat pad at the IER. The deep part of the fat pad at the IER had significantly more blood vessels than the superficial part of the fat pad at the IER (P = 0.012). Significantly more blood vessels than free nerve endings were seen in all three groups (P < 0.001). No significant differences in distribution were seen in terms of right or left side, except for free nerve endings in the superficial part of the fat pad at the IER (P = 0.003). A greater number of free nerve endings correlated with a greater number of blood vessels. The presence of sensory nerve endings between individual fat cells supports the hypothesis that the fat pad has a proprioceptive role monitoring changes and that it is a source of pain in sinus tarsi syndrome due to the abundance of free nerve endings.