Clinical presentation of group B Streptococcus-infected diabetic foot ulcers

OBJECTIVE

Group B Streptococcus (GBS) is a common pathogen in diabetic foot ulcers (DFUs), where it has been found to result in higher rates of soft tissue infection and amputation despite appropriate treatment. In this study, we aim to investigate clinical characteristics and prognosis of GBS DFU infections, especially those with tenosynovial involvement. We hypothesise that GBS-infected DFUs with tenosynovial involvement leads to an increased number of recurrent infections and unexpected returns to the operating room.

METHOD

Data were retrospectively collected from GBS-infected DFU patients surgically treated by an orthopaedic foot and ankle surgeon over a four-year period. Demographics, comorbidities, initial laboratory values and culture results from infected bone samples were recorded. Clinical outcome was assessed by recurrent infection and unplanned reoperation(s) within 3 months following the initial surgery.

RESULTS

In total, 72 patients were treated for GBS-infected DFUs. Intra-operative culture of infected bone identified GBS in 16 patients (22.2%). Significantly more black patients (p=0.017) were afflicted by GBS DFUs. Patients with GBS DFUs had higher initial haemoglobin A1C levels (p=0.019), and those with tenosynovial involvement were likely to require reoperation (p=0.036) and had a greater total number of surgeries (p=0.015) than those without.

CONCLUSION

GBS-infected DFUs are more common in black patients and those with elevated haemoglobin A1Cs. GBS infections with tenosynovial involvement are particularly destructive and require aggressive treatment by surgeons.

Clinical Improvement Following Operative Management of Ankle Fractures Among Patients With and Without Moderate to High Depressive Symptoms: An Analysis Using PROMIS

Background

Understanding the recovery trajectory following operative management of ankle fractures can help surgeons guide patient expectations. Further, it is beneficial to consider the impact of mental health on the recovery trajectory. Our study aimed to address the paucity of literature focused on understanding the recovery trajectory following surgery for ankle fractures, including in patients with depressive symptoms.

Methods

From February 2015 to March 2020, patients with isolated ankle fractures were asked to complete Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF), Pain Interference (PI), and Depression questionnaires as part of routine care at presentation and follow-up time points. Linear mixed effects regression models were used to evaluate the patient recovery pattern, comparing the preoperative time point to <3 months, 3-6 months, and >6 months across all patients. Additional models that included the presence of depression symptoms as a covariate were then used.

Results

A total of 153 patients met inclusion criteria. By 3-6 months, PROMIS PF (β: 9.95, 95% CI: 7.97-11.94, P < .001), PI (β: -10.30, 95% CI: -11.87 to -8.72, P < .001), and Depression (β: -5.60, 95% CI: -7.01 to -4.20, P < .001) improved relative to the preoperative time point. This level of recovery was sustained thereafter. When incorporating depressive symptoms into our model as a covariate, the moderate to high depressive symptoms were associated with significantly and clinically important worse PROMIS PF (β: -4.00, 95% CI: -7.00 to -1.00, P = .01) and PI (β: 3.16, 95% CI: -0.55 to 5.76, P = .02) scores.

Conclusion

Following ankle fracture surgery, all patients tend to clinically improve by 3-6 months postoperatively and then continue to appreciate this clinical improvement. Although patients with moderate to high depressive symptoms also clinically improve following the same trajectory, they tend to do so to a lesser level than those who have low depressive symptoms.

Level of Evidence

Level III, case-control study.

Noninvasive Measurement of Normal Foot and Ankle Joint Reaction Force

Category:

Basic Sciences/Biologics

Introduction/Purpose:

Various biomechanical studies have examined pressure changes across the foot and ankle joints. However, most of these studies disrupted the capsuloligamentous complex surrounding the joint to insert pressure sensors, compromising the integrity of the natural joint structure and the accuracy of biomechanical assessments. This is the first noninvasive study to report measurement of natural joint reaction forces (JRF) across the foot and ankle while preserving all soft tissue structures. Since articular surfaces experience equal and opposing compression forces, we aimed to evaluate the distraction force needed to overcome these compression forces.

Methods:

Ten fresh-frozen cadavers of the lower extremity were obtained that were disarticulated at the knee joint. Steinmann pins were percutaneously placed across the distal tibia, and the center of the talus, navicular, cuboid, and calcaneus while preserving all surrounding soft tissues. A custom fixation device was utilized in conjunction with a tensile testing machine to allow distraction in line with the axis of the tibiotalar, subtalar, talonavicular (TN), and calcaneocuboid (CC) joints. Displacement was measured as distance between Steinmann pins on either side of the joint examined. Under progressive axial distraction, displacement and force were measured. Best-fit polynomials were calculated to fit the force-displacement curves. The inflection point, representing the joint reaction force (JRF) where distraction forces across the joint equal the compression forces, was calculated for each curve.

Results:

All force-displacement curves demonstrated an inflection point. Prior to the inflection point, relatively large increases in distraction force resulted in minimal displacement. Once the inflection point was reached, relatively small increases in distraction force resulted in large increases in displacement. Each cadaver was measured three times with high reproducibility. The mean JRF were tibiotalar 33.8 N [standard deviation (SD) 10], subtalar 18.2 N (SD 12), TN 13.3 N (SD 4), and CC 14.7 N (5.8).

Conclusion:

We present the first application of a reliable and noninvasive method of measuring JRF of the foot and ankle joints. In the medium or small joints, dissection of the capsule and surrounding ligaments can significantly alter joint stability and biomechanics. By preserving all the periarticular soft tissues, this experimental model will allow future investigation of biomechanical changes of pathologic states and efficacy of surgical intervention under conditions that most accurately reflect the in vivo state.

2016 J. Leonard Goldner Award - Can Initial PROMIS Scores Predict Outcome for Foot and Ankle Patients?

Category:

Other

Introduction/Purpose:

The use of patient reported outcomes continues to expand beyond the scope of clinical research to involve standard of care assessments across orthopaedic practices. It is currently unclear how to interpret and apply this information in the daily care of patients. We examined the relationship between patient reported outcomes (PROMIS Physical Function, Pain Interference and Depression scores) obtained at initial visit as a predictor of outcome at a minimum of 7 month follow up.

Methods:

Prospective collection of all consecutive patient visits to the University of Rochester Orthopaedic foot and ankle clinic was initiated on April 2015. Data through December 2015 was classified as new or follow up and operative or non-operative based on ICD-9 and CPT codes. 17,019 patient visits were collected on 7,265 patients, of which 4,213 were new patients. PROMIS physical function, pain interference, and depression scores were assessed at initial and follow up visits. Only patients with a minimum of 7 months (mean 8.2) follow up who completed all PROMIS domains were included, resulting in 262 patients (69 operative, 193 non-operative). PROMIS scores are normalized to a US population with an average score of 50 and a standard deviation of 10. Statistical analysis using student t-tests and linear regression were performed to determine if the initial PROMIS scores were predictive of patient reported outcomes at final follow up.

Results:

There were no differences between operative and non-operative treatment groups in initial PROMIS scores or change in scores at follow up (p>0.40). Patients with higher baseline pain were likely to experience less pain over time (r=0.63, p < 0.01). Similarly, patients with higher baseline depression were likely to experience decreased depression over time (r =0.52, p < 0.01). Patients with lower baseline physical function were likely to improve over time whereas patients with higher baseline physical function were likely to worsen over time (r=0.68, p< 0.01). Specifically, all patients with baseline physical function score less than 28 improved over time, while all patients with a score greater than 52 worsened (Figure 1).

Conclusion:

Physical function, pain, and depression trends did not vary between operative and non-operative patients at 8.2 month follow up. Patients with high initial pain and depression were likely to have improvements in pain and depression over time. Similarly, patients with low initial physical function were likely to have improved physical function. However, despite treatment, patients with above average initial physical function did not experience improvement in physical function, suggesting these patients are more challenging to treat. This information demonstrates that baseline patient reported outcomes are predictive of improvement in outcomes over time, and could assist in the treatment decision process.

Spring Ligament Tear Decreases the Ankle and Talonavicular Joint Reaction Forces

Category:

Other

Introduction/Purpose:

Spring ligament tear is often noted in advanced stages of the adult acquired flatfoot deformity (AAFD). Previous anatomic studies demonstrated that the spring and deltoid ligaments are not separate structure, but form a confluent ligament in which the tibiocalcaneonavicular ligament (TCNL) comprises the largest component. A biomechanical study which utilized stage IIB AAFD model demonstrated inferior result of the anatomic spring ligament reconstruction compared to the tibionavicular ligament reconstruction. Therefore, the TCNL reconstruction has been proposed for effective restoration of the ankle and talonavicular joints stability in AAFD with a large spring ligament tear. We aimed to investigate if spring ligament tear of greater than 1.5 cm decreases the ankle and talonavicular joint reaction forces (JRF), and if they could be restored by the TCNL reconstruction.

Methods:

Ten fresh-frozen human cadaveric lower legs were obtained and disarticulated at the knee joint. Steinmann pins were percutaneously placed across the distal tibia, center of the talus and navicular while preserving adjacent soft tissues. A distraction force was applied across the ankle and talonavicular joints to determine the baseline force displacement curve to generate a best- fit polynomial equation to determine normal JRF. A spring ligament injury model was created by releasing the medial capsuloligamentous complex of the talonavicular joint and extending the resection 1.5 cm proximally. The TCNL reconstruction was performed with a forked semitendinosus allograft. The folded portion of the graft was fixed to the medial malleolar inter- colliculus. One limb of the separated part of the allograft was fixed to the navicular tuberosity and the other limb was fixed to the calcaneus below the sustentaculum tali. The resultant JRFs across the tibiotalar and talonavicular joints were measured after each step.

Results:

The mean baseline JRFs of the ankle and talonavicular joints were 8.36 N +/- 1.8 N and 3.01 N +/- 0.9 N, respectively. The spring ligament tear resulted in 29% decrease in tibiotalar JRF (5.97 N +/- 1.1 N, p< 0.05) and 13% decrease in talonavicular JRF (2.63 N +/- 0.8 N, p>0.05). Although the tibionavicular ligament reconstruction partially restored JRFs of the tibiotalar (7.83 +/- 2.4 N, p> 0.05) and talonavicular joints (4.08 N +/- 1.8 N, p> 0.05), they were not statistically significant. Addition of the tibiocalcaneal ligament reconstruction resulted in significantly increased JRFs of the tibiotalar (9.17 +/- 3.93 N, p> 0.05) and talonavicular joints (4.35 +/- 2.04 N, p> 0.05) compared to the spring ligament injury model.

Conclusion:

This is the first biomechanical study to demonstrate that a large size (>1.5 cm) spring ligament tear results in decreased JRF of the ankle joint. The decreased ankle and talonavicular JRFs were effectively restored by the novel TCNL reconstruction. This technique utilizes a forked allograft with two limbs for the tibionavicular and tibiocalcaneal ligaments reconstructions. Advanced AAFD with a large size spring ligament tear may have medial ankle instability that should not be overlooked. The novel TCNL reconstruction should be considered to prevent progression of valgus deformity. The biomechanical and clinical efficacies of the TCNL reconstruction warrant further investigation.

A Novel Method for Measurement of Ankle Joint Reaction Force and Response to Syndesmotic Injury

Category:

Ankle.

Introduction/Purpose:

Increasing evidence has suggested that alterations in joint mechanics results in articular pathology. Previous studies demonstrated noninvasive measurements of joint reactive forces (JRF) can be performed reliably without destruction of the peri-articular soft tissue in medium and small size joints of the upper extremity. This study presents a novel, noninvasive measurement of the JRF to investigate the normal and the effects of a syndesmotic injury. The JRF of the tibiotalar joint was also evaluated following anatomic reduction with fixation and malreduction of the syndesmosis.

Methods:

Eight fresh-frozen human cadaveric lower extremity limbs were obtained disarticulated above the knee. A distraction force was applied across the tibio-talar joint to determine the baseline (normal) ankle force displacement curve. Next, a syndesmotic injury was created by releasing the interosseous syndesmotic ligaments, the transverse tibiofibular ligament and the anterior and posterior tibiofibular ligaments. Prior to sectioning, two drill holes were placed across the joint and tapped to ensure anatomic reduction. JRF were measured using a quadricortical technique with a single or double screw configuration. The syndesmosis was malreduced by anteriorly displacing the fibula 5 mm. After each step, the resultant JRFs were determined using a distraction force across the tibiotalar joint.

Results:

Force displacement curves obtained from multiple measurements from each specimen with a mean ankle JRF of 31.4 + 2.6 N. Syndesmotic injury resulted in a 35% decrease in tibiotalar JRF (20.3 + 3.0 N, p=0.002). Fixation of the injury using one syndesmotic screw resulted in significant increase in JRF compared to injury JRF (28.7 + 1.4 N, p=0.02). Syndesmotic fixation with 2 screws also demonstrated a trend towards restoration of tibiotalar JRF (28.3 + 2.2 N, p=0.06). There was no statistical difference between fixation of one versus two syndesmotic screws. The JRF for the malreduced syndesmosis was 31.5 + 1.8 N (p=0.03,) resulting in increased forces approaching the baseline JRF.

Conclusion:

This study demonstrates a non-destructive model by which to measure joint reactive forces (JRF) across the tibiotalar joint and that these forces are diminished as a result of a syndesmotic injury, suggesting joint instability. Surgical stabilization with either 1 or 2 screws creates JRF that are similar to the normal JRF. Even with a malreduced syndesmosis, there appeared to be a JRF similar to baseline tibiotalar joint forces. However malreduction of the syndesmosis may alter the joint dynamics of the ankle in ways that were not measured in this study.

Routine histopathologic evaluation in hallux valgus surgery

BACKGROUND

Anecdotal evidence suggests that specimens submitted for histopathologic assessment during hallux valgus surgery most commonly reveal degenerative changes. The purpose of this study was to evaluate the cost effectiveness of routine examination of tissue from hallux valgus procedures. We hypothesized that such examination rarely diagnoses a new condition and does not alter postoperative management.

MATERIALS AND METHODS

Specimens from 315 consecutive primary hallux valgus reconstructions performed between November 1995 and August 2002 were retrospectively analyzed. Patient charts were reviewed to determine the number of cases in which new diagnoses were made or treatment altered based upon histopathologic examination. Cost effectiveness was assessed by identifying the reimbursement for professional fees charged for these analyses. The total reimbursement per new diagnosis made and per alteration of treatment were calculated.

RESULTS

Degenerative changes were diagnosed in the majority of speciments (97.5%, 307 of 315). Other diagnoses included rheumatoid arthritis (1.3%, four of 315), gouty arthritis (1.0%, three of 315), and pseudogout (0.3%, one of 315). A new diagnosis was made only in the one patient (0.3%, one of 315) with pseudogout. Postoperative management was unchanged in every case.

CONCLUSION

Routine submission of specimens obtained during hallux valgus surgery is not cost effective. New diagnoses are very rare and postoperative management did not change.