Validating an Algorithm to Predict Adjacent Musculoskeletal Infections in Pediatric Patients With Septic Arthritis.

BACKGROUND: Septic arthritis is frequently associated with adjacent infections including osteomyelitis and subperiosteal and intramuscular abscesses. While often clinically indiscernible from isolated septic arthritis, the diagnosis of adjacent infections is important in determining the need for additional surgical intervention. MRI has been used as the diagnostic gold standard for assessing adjacent infection. Routine MRI, however, can be resource-intensive and delay surgical treatment. In this context, there is need for additional diagnostic tools to assist clinicians in determining when to obtain preoperative MRI in children with septic arthritis. In a previous investigation by Rosenfeld et al., an algorithm, based on presenting laboratory values and symptoms, was derived to predict adjacent infections in septic arthritis. The clinical applicability of the algorithm was limited, however, in that it was built from and applied on the same population. The current study was done to address this criticism by evaluating the predictive power of the algorithm on a new patient population. QUESTIONS/PURPOSES: (1) Can a previously created algorithm used for predicting adjacent infection in septic arthritis among pediatric patients be validated in a separate population? METHODS: Records for all pediatric patients (1-18 years old) surgically treated for suspected septic arthritis during a 3-year period were retrospectively reviewed (109 patients). Of these patients, only those with a diagnosis of septic arthritis confirmed by synovial fluid analysis were included in the study population. Patients without confirmation of septic arthritis via synovial fluid analysis, Gram stain, or culture were excluded (34 patients). Patients with absence of MRI, younger than 1 year, insufficient laboratory tests, or confounding concurrent illnesses also were excluded (18 patients), resulting in a total of 57 patients in the study population. Five variables which previously were shown to be associated with risk of adjacent infection were collected: patient age (older than 4 years), duration of symptoms (> 3 days), C-reactive protein (> 8.9 mg/L), platelet count (< 310 x 10 cells/µL), and absolute neutrophil count (> 7.2 x 10 cells/µL). Adjacent infections were determined exclusively by preoperative MRI, with all patients in this study undergoing preoperative MRI. MR images were read by pediatric musculoskeletal radiologists and reviewed by the senior author. According to the algorithm we considered the presence of three or more threshold-level variables as a "positive" result, meaning the patient was predicted to have an adjacent infection. Comparing against the gold standard of MRI, the algorithm's accuracy was evaluated in terms of sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS: In the new population, the sensitivity and specificity of the algorithm were 86% (95% CI, 0.70-0.95) and 85% (95% CI, 0.64-0.97), respectively. The positive predictive value was determined to be 91% (95% CI, 0.78-0.97), with a negative predictive value of 77% (95% CI, 0.61-0.89). All patients meeting four or more algorithm criteria were found to have septic arthritis with adjacent infection on MRI. CONCLUSIONS: Critical to the clinical applicability of the above-mentioned algorithm was its validation on a separate population different from the one from which it was built. In this study, the algorithm showed reproducible predictive power when tested on a new population. This model potentially can serve as a useful tool to guide patient risk stratification when determining the likelihood of adjacent infection and need of MRI. This better-informed clinical judgement regarding the need for MRI may yield improvements in patient outcomes, resource allocation, and cost. LEVEL OF EVIDENCE: Level II, diagnostic study.

Sagittal mechanical ratio: A novel technique to define sagittal alignment of the femur independent of distal anatomic landmarks.

BACKGROUND: Radiographic measurements to study sagittal alignment in the setting of knee are frequently difficult to evaluate due the presence of a prosthesis or implant that obscures traditional radiographic landmarks. In this paper we present a novel method of determining sagittal femoral alignment in the presence of obscuring implants. METHODS: 98 full-length femoral radiographs were reviewed and divided into two groups. In Group 1, the Distal Mechanical Point (DMP) was used to calculate the Distal Mechanical Ratio (DMR), defined as the ratio of the linear distance from the DMP to the anterior cortical axis divided by the distance from the anterior cortical axis to posterior condylar cortex. In group 2, the sagittal mechanical axis was measured using the true DMP (tDMP) and then separately measured using the DMR to find the calculated DMP (cDMP), and the angular variance between the calculated (cSMA) and true (tSMA) sagittal mechanical axis was calculated, as well as the linear distance between the tDMP and cDMP. Twenty additional patients with knee replacements were then selected and two observers used a cSMA to determine a femoral prosthesis flexion angle (FPFA), with intraobserver correlation calculated. RESULTS: The mean DMR was found to be 0.24, with high intraobserver correlation and normal distribution. Validation of the model demonstrated angular variance between tSMA and cSMA less than 1 degree and linear distance between tDMP and cDMP less than 1 mm. Calculation of cCMA in the presence of total knee arthroplasty revealed very strong intraobserver correlation of 0.89. CONCLUSION: The Distal Mechanical Ratio reliably predicted the true Sagittal Mechanical Axis within 1 degree and true Distal Mechanical Point within 1 mm, indicating that it may be a valuable tool for evaluating sagittal femoral alignment in cases where anatomic landmarks may be absent or obscured.

Primary Arthrodesis of Non-thumb Metacarpophalangeal Joints of the Hand: Clinical and Patient-Reported Outcomes.

BACKGROUND: Metacarpophalangeal (MCP) joint arthritis is common secondary to a variety of inflammatory, degenerative, and traumatic causes. Although MCP arthroplasty is more common for the second to fifth digits, primary arthrodesis can be used for high-demand patients with arthritis or unsalvageable fractures of the MCP joint. There has been limited recent studies on the outcomes of these patients. METHODS: A retrospective review of 38 fingers in 27 patients with primary arthrodesis from 1990 to 2020 was conducted. The major outcomes were complications, reoperations, radiographic union, and time to union. Patient-reported outcomes including the Michigan Hand Outcomes Questionnaire and a questionnaire specific to the operative MCP joint were collected. RESULTS: Rate of radiographic union was 84% including revisions. The average time to union was 3.6 months. Rates of complications, reoperation, and amputation were 26%, 16%, and 7%, respectively. Arthrodesis as part of emergent trauma reconstruction was significantly more likely to result in reoperation (50% vs 7%) and complication (63% vs 17%) than chronic arthritis. Patient-reported outcomes were fair to good with improvement in pain (79%), function (66%), and appearance (40%). Sixty-six percent (66%) of patients were satisfied with their surgery, and 73% would repeat the surgery. CONCLUSION: Arthrodesis for unsalvageable MCP fractures was associated with higher rates of reoperation and complication than inflammatory or degenerative arthritis. Excluding emergent trauma, MCP fusion was reliable with a reoperation rate of 7% and a modest complication rate of 17%. Patients rated reasonable levels of satisfaction and willingness to repeat the procedure despite complications.

Resilience correlates with patient-reported outcome measures at a minimum of 2 years after arthroscopic rotator cuff repair.

Aims: We aimed to evaluate the correlation between preoperative and postoperative resilience scores and postoperative outcomes at minimum 2-year follow-up after arthroscopic rotator cuff repair. Methods: We prospectively enrolled 98 patients who underwent rotator cuff repair. We assessed resilience using the Brief Resilience Scale. Postoperatively, we obtained patient-reported outcomes measures including American Society of Shoulder and Elbow Surgeons scores, Single Assessment Numeric Evaluation, and Patient-Reported Outcome Measurement Information System Global Health-10 at minimum 2-year follow-up. We used Spearman correlation coefficients (r) to assess the relationship between variables. Results: Ninety-one of 98 patients (93%) provided follow-up at an average of 32 months. Preoperative Brief Resilience Scale did not show a statistically significant correlation with American Society of Shoulder and Elbow Surgeons (r = 0.156; p = 0.142). However, preoperative Brief Resilience Scale showed statistically significant correlations with Patient-Reported Outcome Measurement Information System Global Health-10 (r = 0.290; p = 0.005) and Single Assessment Numeric Evaluation (r = 0.259; p = 0.014). Postoperative Brief Resilience Scale showed statistically significant correlations with American Society of Shoulder and Elbow Surgeons (r = 0.291; p = 0.005), Single Assessment Numeric Evaluation (r = 0.384; p < 0.001) and Patient-Reported Outcome Measurement Information System Global Health-10 (r = 0.515; p < 0.001). Discussion: Resilience may be a valuable predictor of patients at risk of having suboptimal outcomes after rotator cuff repair and a target to improve surgical outcomes through non-surgical means.

Impact of patient resilience on early recovery from rotator cuff repair.

Aims: We sought to evaluate early recovery from rotator cuff repair by assessing the correlation between patient resilience and postoperative shoulder pain and function, and physical and mental health. Methods: Patients scheduled to undergo arthroscopic rotator cuff repair were prospectively enrolled. Resilience was assessed using the Brief Resilience Scale (BRS), pain and function was measured by American Society of Shoulder and Elbow Surgeons (ASES) shoulder scores, and physical and mental health was measured by the Patient-Reported Outcome Measurement Information System Global Health-10 (PROMIS-10). All scores were obtained preoperatively and postoperatively at three- and six months. Spearman correlation coefficient (r) was used to assess the relationship between variables. Results: Ninety-eight patients ultimately underwent rotator cuff repair; 76 and 68 patients provided three- and six-month follow-up, respectively. There was no statistically significant correlation between preoperative BRS and three- and six-month ASES. However, there was a statistically significant correlation between preoperative BRS and three-month PROMIS-10 (r = 0.3763, p = 0.009) and concurrent BRS and PROMIS-10 at three months (r = 0.5657, p = 0.0025) and six months (r = 0.5308, p = 0.0025). Discussion: Resilience appears to be more predictive of global physical and mental health than shoulder pain and function in early recovery from rotator cuff repair.