Editorial: Sparse-data Bias-What the Savvy Reader Needs to Know

Does the Extent of Tear Influence Pseudoparesis in Patients With Isolated Subscapularis Tears?

BACKGROUND

Surgeons tend to associate pseudoparesis with massive rotator cuff tears. However, little is known about the degree to which isolated subscapularis tears might be associated with pseudoparesis of the shoulder.

QUESTION/PURPOSE

Is the extent of subscapularis tears associated with pseudoparesis?

METHODS

A retrospective analysis identified all patients with subscapularis tears from 2010 to 2021 in the longitudinally maintained shoulder arthroscopy archive of one university hospital's shoulder section of the orthopaedic department. After exclusion, 106 of 152 patients with isolated subscapularis tears who underwent arthroscopic surgery were included in the study. Sixty percent of the patients were women, and the mean ± SD age was 52 ± 11 years. Patients who were scheduled for arthroscopic surgery were divided into two groups according to the presence or absence of pseudoparesis preoperatively. Pseudoparesis was considered to be active forward elevation > 45º but < 90º, which is a simple and reproducible measurement that can be taken using a goniometer, and demonstrated complete passive forward elevation. Pseudoparesis was present in 41% (43 of 106) of patients with an isolated subscapularis tear. Data on tear severity (according to Lafosse type, noted during arthroscopy), integrity of the subscapularis tendon (noted during arthroscopy), fatty degeneration (using the Goutallier grading system on MRI), arthroscopic findings of biceps disorder, superior labrum anterior to posterior (SLAP) lesions, and pain severity (measured by VAS score) were recorded. We used logistic regression analysis to examine the relationship between pseudoparesis and disruption of the tendinous part of the subscapularis.

RESULTS

After accounting for potentially confounding factors such as biceps disorders and muscle atrophy, we found that pseudoparesis was associated with decreased tear severity according to the Lafosse classification (adjusted OR 0.2 [95% CI 0.1 to 0.7]; p = 0.01) and with disruption of the tendinous portion of the subscapularis (adjusted OR 21 [4 to 128]; p = 0.001). Patients with less severe tears (Lafosse type I) have lower odds of experiencing pseudoparesis compared with those with more severe tears (Lafosse types II, III, and IV), and patients with disruption of the tendinous portion of the subscapularis have substantially higher odds of pseudoparesis compared with those with an intact tendinous portion. No association was found between pseudoparesis and subscapularis fatty degeneration, biceps disorder, or SLAP lesions.

CONCLUSION

This study provides initial evidence suggesting that isolated subscapularis tears are associated with pseudoparesis. The main finding of this study is that isolated subscapularis tears that involve the tendon extending to the inferior part of the subscapularis have higher odds of being found with pseudoparesis. These findings highlight the importance of maintaining the integrity of the superior tendinous part of the subscapularis for active forward elevation > 90°.

LEVEL OF EVIDENCE

Level III, therapeutic study.

What Are the Long-term Outcomes of Locking Plates for Nonosteoporotic Three-part and Four-part Proximal Humeral Fractures With a Minimum 10-year Follow-up Period?

BACKGROUND

Proximal humeral fractures (PHFs) often occur in elderly individuals who experience low-energy falls. Open reduction and internal fixation (ORIF) of the proximal humerus is typically performed in young, active patients because of their good bone quality and high functional demands. Although good short-term results have been reported after ORIF in young patients, few studies have specifically evaluated long-term outcomes.

QUESTIONS/PURPOSES

(1) What are the long-term clinical outcomes scores and (2) radiologic outcomes of nonosteoporotic three-part and four-part PHFs treated with locking plates? (3) What complications occurred after treatment, and what factors are associated with poor postoperative functional outcomes scores and avascular necrosis (AVN) of the humeral head after ORIF?

METHODS

Between June 2005 and December 2012, we surgically treated 774 patients for displaced two-, three-, and four-part PHFs. Approximately 75% (581 of 774) underwent ORIF, 10% (77 of 774) underwent hemiarthroplasty, 7% (54 of 774) underwent intramedullary nailing, 5% (39 of 774) underwent reverse shoulder arthroplasty, and the remaining 3% (23 of 774) underwent other surgical treatments. We considered those who had ORIF as potentially eligible. Based on that criterion, 75% (581) were eligible. However, only patients with nonosteoporotic three- and four-part PHFs (cortical thickness of the proximal humeral diaphysis greater than 6 mm on a preoperative AP radiograph of the affected shoulder) and a minimum of 10 years of follow-up were included. Sixty-four percent (498 of 774) of the patients were excluded because of simple or osteoporotic fractures, 1% (7 of 774) were excluded because of ipsilateral limb multiple fractures, 0.3% (2 of 774) were excluded because of pathologic PHFs, and another 2% (13 of 774) were lost before the minimum study follow-up of 10 years, leaving 8% (61 of 774) for analysis here. The mean age at surgery was 45 ± 12 years, with a mean follow-up of 13 years. Fifty-seven percent (35 of 61) of the patients were men. Patient-reported outcomes were evaluated using the University of California Loas Angeles (UCLA) score (range 0 to 35; higher scores represent better shoulder function) and Constant score (range 0 to 100; higher scores represent better shoulder function) at least 10 years postoperatively. Postoperative radiographs were reviewed to assess the cortical bone thickness of the proximal humerus, neck-shaft angle, head-to-tuberosity distance, and radiologically confirmable complications. Logistic regression analysis was performed to evaluate factors associated with poor postoperative functional scores (UCLA score ≤ 27 or Constant score ≤ 70) and AVN of the humeral head; the association between AVN and postoperative functional outcomes was also assessed.

RESULTS

At the most-recent follow-up, these patients had a mean UCLA score of 31 ± 3 and a Constant score of 88 ± 10. The mean neck-shaft angle was 133° ± 10°, and 23% (14 of 61) of patients experienced AVN of the humeral head during follow-up. Twenty-nine complications in 30% (18 of 61) of patients were reported. After controlling for potentially confounding variables such as age and gender, we found that the presence of greater tuberosity malposition (odds ratio 18 [95% confidence interval 2 to 167]; p = 0.01) and immediate postoperative neck-shaft angle less than 130° (OR 19 [95% CI 3 to 127]; p = 0.002) were associated with poor postoperative functional scores. Four-part PHFs (OR 13 [95% CI 2 to 82]; p = 0.008) and metaphyseal extension less than 8 mm (OR 7 [95% CI 1 to 35]; p = 0.03) were associated with AVN of the humeral head. For patients who met the criteria for anatomic reduction (achievement of all of the following three criteria: neck-shaft angle ≥ 130°, head-shaft displacement < 5 mm, and head-to-tuberosity distance greater than or equal to 3 mm and less than or equal to 20 mm), there were no differences in postoperative functional scores between patients with AVN and those without.

CONCLUSION

ORIF of nonosteoporotic proximal humeral fractures with locking plates led to favorable functional and radiologic outcomes at a minimum of 10 years of follow-up. When encountering complex PHFs in patients with good bone quality, every effort must be made to achieve an anatomic reduction of the fracture as far as possible, which may not reduce the risk of AVN (this occurred in nearly one-fourth of patients). However, good outcomes can usually be expected, even in patients with AVN. Because this was a retrospective study with a high risk of bias owing to sparse data, the factors associated with poor postoperative functional outcomes must be further investigated in large prospective studies.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Lack of association between XRCC1 SNPs and acute radiation‑induced injury or prognosis in patients with nasopharyngeal carcinoma

The response to radiation therapy (RT) is closely associated with DNA damage repair. X-ray repair cross-complementing group-1 (XRCC1) is a key gene in the DNA damage repair pathway, and SNPs in this gene alter the expression and activity of its effector protein, which may in turn affect sensitivity to RT. Therefore, the course of tumor treatment and local control rate can be influenced. In the present study, a group of 158 patients with nasopharyngeal carcinoma (NPC) who received intensity-modulated RT at Fujian Cancer Hospital (Fuzhou, China) between July 2012 and October 2013 were included in retrospective chart review and followed up. Plasma was collected before treatment for genotype analysis of the three SNPs of XRCC1, namely Arg194Trp, Arg280His and Arg399Gln. Acute radiation-induced injuries sustained during treatment was graded according to the Radiation Therapy Oncology Group scoring criteria. Post-treatment follow-up was performed until August 2020. In the 158 cases of NPC, no statistically significant association was observed between the three SNPs of the XRCC1 gene and the severity of acute radiation-induced injury or prognosis. However, the AA genotype of XRCC1-Arg399Gln tended to be associated with worse progression-free survival (PFS) compared with the GA + GG genotype, although this was not significant (P=0.069). In addition, multivariate logistic analysis showed that nodal stage was significantly associated with the occurrence of acute severe radiation-induced oral mucositis (P=0.018), and there was also a trend towards an association between nodal stage and the incidence of acute severe radiation-induced pharyngitis; however, this was not statistically significant (P=0.061). Furthermore, multivariate Cox regression analysis showed that older age, distant metastasis and higher clinical stage were independent risk factors for PFS in patients with NPC. In conclusion, relying solely on the aforementioned SNPs of the XRCC1 gene may not provide a robust enough basis to predict the response to RT or prognosis in patients with NPC.

Orthopaedic knee scooter-related injury: prevalence and patient safety perception in a prospective cohort with exploratory risk factor analysis

BACKGROUND

There is a paucity of research investigating the harms associated with orthopaedic knee scooter (OKS) use and patient safety perceptions. This prospective study aimed to define the prevalence of OKS-related injuries, describe the patient perceptions of OKS safety, and identify potential risk factors.

METHODS

This study was conducted at a single foot and ankle fellowship-trained surgeon's community-based clinic from 6/2020 to 4/2021 and enrolled 134 patients. Our primary outcome was an OKS-related event (injury or fall) and informed an a priori power analysis. Point estimate of association magnitude was calculated as an odds ratio (OR) for statistically and clinically significant associations.

RESULTS

There were 118 (88%) patients eligible for analysis; fourteen enrolled patients did not use OKS, and two withdrew. The prevalence of patient falls was 37% (44/118), and the prevalence of patient injury was 15% (18/118). Four percent of patients would not recommend OKS and 8% would not use an OKS again. Sedentary lifestyle increased risk (OR = 4.67, 1.52-14.35 95 CI) for OKS-related injury.

CONCLUSIONS

Despite a high prevalence of patient falls (37%), there is a low prevalence of injury (15%) and a favorable perception of OKS safety. Sedentary lifestyles may be a risk factor for OKS-related injury and should be considered in the development of a risk model.

Are Observational Studies on Distal Radius Fracture Treatment Robust? An E-value Approach to Analysis

BACKGROUND

Reported complication frequencies after distal radius fracture (DRF) treatment vary widely in the literature and are based mostly on observational evidence. Whether that evidence is sufficiently robust to use in practice is controversial. The E-value is an innovative sensitivity analysis that quantitates the robustness of observational evidence against unmeasured confounders, whereby a greater E-value usually implies more robust evidence and vice versa; with DRF complications, this approach can help guide readers to a more confident interpretation of the available evidence.

QUESTIONS/PURPOSES

In this study, we sought (1) to compare the complication frequencies among different DRF treatment modalities, and (2) to evaluate the robustness of these observational studies using the E-value as an index for unmeasured confounding.

METHODS

We searched PubMed, Embase, and SCOPUS for observational studies on the management of DRFs that were published from January 2001 to July 2021 with the last database search performed on July 31, 2021. All articles that compared different DRF treatment modalities with reported complication frequencies were included to accurately capture the quality of the observational studies in research about DRF. Risk ratios (RRs) of the overall complication and major complication risks were calculated for each subgroup comparison: volar plating versus dorsal plating, casting, external fixation, and percutaneous K-wire fixation. The RRs and their corresponding lower limits of the 95% confidence intervals (CIs) were used to derive the E-values. E-values can have a minimum possible value of 1, which signifies that the treatment-outcome association is not strong and can readily be overturned by unmeasured confounders. By contrast, a large E-value means that the observed treatment-outcome association is robust against unmeasured confounders. We averaged RRs and E-values for the effect estimates and lower limits of CIs across studies in each treatment comparison group. We identified 36 comparative observational studies that met the inclusion criteria. Seven studies compared volar with dorsal plating techniques. Volar plating was also compared with casting (eight studies), external fixation (15 studies), and percutaneous K-wire fixation (six studies).

RESULTS

Total and major complication risks did not differ among different DRF treatments. The mean RRs for total and major complications were 1.2 (95% CI 0.4 to 3.9; p = 0.74) and 1.8 (95% CI 0.4 to 11.4; p = 0.52) for the volar versus dorsal plating group; 1.2 (95% CI 0.3 to 11.2; p = 0.87) and 1.5 (95% CI 0.3 to 14.9; p = 0.74) for the volar plating versus casting group; 0.6 (95% CI 0.2 to 2.2; p = 0.33) and 0.8 (95% CI 0.2 to 6.7; p = 0.86) for the volar plating versus external fixation group; and 0.6 (95% CI 0.2 to 2.6; p = 0.47) and 0.7 (95% CI 0.2 to 4.0; p = 0.67) for the volar plating versus K-wire fixation group. The mean E-values for total and major complication frequencies for the between-group comparison ranged from 3.1 to 5.8; these were relatively large in the context of a known complication risk factor, such as high-energy impact (RR 3.2), suggesting a reasonable level of robustness against unmeasured confounding. However, the E-values for lower limits of CIs remained close to 1, which indicates the observed complication frequencies in these studies were likely to have been influenced by unmeasured confounders.

CONCLUSION

Complication frequencies did not differ among different DRF treatment modalities, but the observed complication frequencies from most comparative observational studies were less robust against potential unmeasured confounders. The E-value method, or another type of sensitivity analysis, should be implemented in observational hand surgery research at the individual-study level to facilitate assessment of robustness against potential unmeasured confounders.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Outcome and Predictors of Septic Failure Following Total Joint Arthroplasty for Prior Septic Arthritis of Hip and Knee Joint

BACKGROUND

Arthroplasty patients with prior septic arthritis are at a high risk of developing periprosthetic joint infection (PJI). The aims of this study are to investigate the outcome and predictors of septic failure following total joint arthroplasty (TJA) for prior septic arthritis. In addition, the optimal timing of TJA is also discussed.

METHODS

A retrospective review of 105 TJA patients with prior septic arthritis between January 2000 and December 2019 was performed. Patient-specific and surgery-related factors, organism profiles, and other relevant variables were recorded.

RESULTS

At a mean follow-up of 10.3 years, the PJI rate was 16.2%. The adjusted Cox proportional hazards model showed that male gender (HR, 9.95; P < .01), end-stage renal disease (HR, 37.34; P < .01), debridement surgery ≥3 times (HR,4.75; P = .04) and polymicrobial infection in primary septic arthritis (HR, 10.02; P = .02) were independent risk factors for PJI. Neither the types of initial debridement, nor one-stage vs two-stage arthroplasty was related to the risk of PJI. While delaying the timing of TJA did not correlate with a reduction of PJI rate, there was a higher risk of PJI re-infection by the same microorganisms isolated in prior septic arthritis if TJA was performed within 6 months after septic arthritis.

CONCLUSIONS

Our study demonstrated that male gender, end-stage renal disease (ESRD), multiple debridement surgeries and polymicrobial septic arthritis predisposed septic failure of TJA following prior septic arthritis. Surgeons should counsel patients with the potential complications, and be cognizant about the risk factors pertaining to septic failure when considering TJA.

Factors Associated With Nonunion and Infection Following Ankle Arthrodesis Using a Large Claims Database: Who Has Elevated Risk?

Background:

Complications such as nonunion and infection following ankle arthrodesis can lead to increased patient morbidity and financial burden from repeat operations. Improved knowledge of risk factors can improve patient selection and inform post–ankle arthrodesis surveillance protocols.

Methods:

This is a large retrospective, database study with structured query of a national insurance claims database (PearlDiver Technologies) for patients treated with ankle arthrodesis from 2015 to 2019 as identified by International Classification of Diseases, Tenth Revision (ICD-10), codes. Patients with any operation 1 year prior to or following ankle arthrodesis were excluded from analysis to prevent attributing complications to another operation. Likelihoods of nonunion and infection within 1 year and 3 years following ankle arthrodesis were analyzed using Kaplan-Meier estimations. Patient characteristics associated with the identified complications following ankle arthrodesis were analyzed using multivariable logistic regression analyses.

Results:

Our query yielded 2463 patients in the 5-year period who underwent ankle arthrodesis. Nonunion occurred in 11% (95% CI 10-12) of patients within 1 year of ankle arthrodesis and 16% (95% CI 14-17) of patients within 3 years. Infection occurred in 3.9% (95% CI 3.1-4.7) of patients within 1 year of ankle arthrodesis and in 6.2% (95% CI 5.1-7.2) of patients within 3 years. Obese patients increased odds of nonunion on multivariable analysis (OR 1.6, 95% CI 1.3-2.0; P < .001). On multivariable analysis, diabetes (OR 1.7, 95% CI 1.2-2.6; P = .010) and each 1-unit increase in Elixhauser Comorbidity Index scores (OR 1.1, 95% CI 1.1-1.2; P < .001) contributed to increased odds of infection after ankle arthrodesis.

Conclusion:

Nonunion and infection following ankle arthrodesis have a 3-year probability of 16% and 6%, respectively. More than one-quarter of patients with nonunion following ankle arthrodesis experience a delay in diagnosis beyond 1 year. The risk of post–ankle arthrodesis nonunion is highest in patients with obesity; the risk of post–ankle arthrodesis infection is highest in patients with diabetes or an elevated Elixhauser Comorbidity Index score.

Level of Evidence:

Level III, prognostic study.

Patients Who Undergo Early Aseptic Revision TKA Within 90 Days of Surgery Have a High Risk of Re-revision and Infection at 2 Years: A Large-database Study

BACKGROUND

Early aseptic revision within 90 days after primary TKA is a devastating complication. The causes, complications, and rerevision risks of aseptic revision TKA performed during this period are poorly described.

QUESTIONS/PURPOSES

(1) What is the likelihood of re-revision within 2 years after early aseptic TKA revision within 90 days compared with that of a control group of patients undergoing primary TKA? (2) What are the indications for early aseptic TKA revision within 90 days? (3) What are the differences in revision risk between different indications for early aseptic revision TKA?

METHODS

Patients who underwent unilateral aseptic revision TKA within 90 days of the index procedure were identified in a national insurance claims database (PearlDiver Technologies) using administrative codes. The exclusion criteria comprised revision for infection, history of bilateral TKA, and age younger than 18 years. The PearlDiver database was selected for its large and geographically diverse patient base and the availability of outpatient follow-up data that are unavailable in other databases focused on inpatient care. A total of 481 patients met criteria for early aseptic revision TKA, with 14% (67) loss to follow-up at 2 years. This final cohort of 414 patients was compared with a control group of patients who underwent primary TKA without revision within 90 days. For the control group, 137,661 patients underwent primary TKA without early revision, with 13% (18,138) loss to follow-up at 2 years. Among these patients, 414 controls were matched using a one-to-one propensity score method; no differences in age, gender, and Charlson comorbidity index score were observed between the groups. Indications for initial revision and 2-year re-revision were recorded. The Kaplan-Meier method was used to assess survival between the early revision and control groups.

RESULTS

Two-year survivorship free from additional revision surgery was lower in the early aseptic revision cohort compared with the control (78% [95% confidence interval 77% to 79%] versus 98% [95% CI 96% to 99%]; p < 0.001). Among early revisions, 10% (43 of 414) of the patients underwent re-revision for periprosthetic infection with an antibiotic spacer within 2 years. The reasons for early aseptic revision TKA were instability/dislocation (37% [153 of 414]), periprosthetic fracture (23% [96 of 414]), aseptic loosening (23% [95 of 414]), pain (11% [45 of 414]), and arthrofibrosis (6% [25 of 414]). Early revision for pain was associated with higher odds of re-revision than early revisions performed for other all other reasons (44% [20 of 45] versus 29% [100 of 344]; odds ratio 2.0 [95% CI 1.0 to 3.7]; p = 0.04).

CONCLUSION

Acute early aseptic revision TKA carries a high risk of re-revision at 2 years and a high risk of subsequent periprosthetic joint infection. Patients who undergo an early revision should be carefully counseled regarding the very high risk of repeat revision and discouraged from having early revision unless the indications are absolutely clear and compelling. Early aseptic revision for pain alone carries an unacceptably high risk of repeat revision and should not be performed. Adjunctive measures for infection prophylaxis should be strongly considered. Specific interventions to reduce surgical complications in this subset of patients have not been adequately studied; additional investigation of strategies to minimize the risk of reoperation or infection is warranted.

LEVEL OF EVIDENCE

Level III, therapeutic study.

High rate of second ACL injury following ACL reconstruction in male professional footballers: an updated longitudinal analysis from 118 players in the UEFA Elite Club Injury Study

Background

Studies on subsequent anterior cruciate ligament (ACL) ruptures and career length in male professional football players after ACL reconstruction (ACLR) are scarce.

Aim

To investigate the second ACL injury rate, potential predictors of second ACL injury and the career length after ACLR.

Study design

Prospective cohort study.

Setting

Men’s professional football.

Methods

118 players with index ACL injury were tracked longitudinally for subsequent ACL injury and career length over 16.9 years. Multivariable Cox regression analysis with HR was carried out to study potential predictors for subsequent ACL injury.

Results

Median follow-up was 4.3 (IQR 4.6) years after ACLR. The second ACL injury rate after return to training (RTT) was 17.8% (n=21), with 9.3% (n=11) to the ipsilateral and 8.5% (n=10) to the contralateral knee. Significant predictors for second ACL injury were a non-contact index ACL injury (HR 7.16, 95% CI 1.63 to 31.22) and an isolated index ACL injury (HR 2.73, 95% CI 1.06 to 7.07). In total, 11 of 26 players (42%) with a non-contact isolated index ACL injury suffered a second ACL injury. RTT time was not an independent predictor of second ACL injury, even though there was a tendency for a risk reduction with longer time to RTT. Median career length after ACLR was 4.1 (IQR 4.0) years and 60% of players were still playing at preinjury level 5 years after ACLR.

Conclusions

Almost one out of five top-level professional male football players sustained a second ACL injury following ACLR and return to football, with a considerably increased risk for players with a non-contact or isolated index injury.

Can a Novel Scoring System Improve on the Mirels Score in Predicting the Fracture Risk in Patients with Multiple Myeloma?

BACKGROUND

Stratification of the fracture risk is an important treatment component for patients with multiple myeloma, which is associated with up to an 80% risk of pathologic fracture. The Mirels score, which is commonly used to estimate the fracture risk for patients with osseous lesions, was evaluated in a cohort in which fewer than 15% of lesions were caused by multiple myeloma. The behavior of multiple myeloma lesions often differs from that of lesions caused by metastatic disease, and accurate risk stratification is critical for effective care. To our knowledge, the Mirels score has not been validated specifically for multiple myeloma.

QUESTIONS/PURPOSES

Our purpose was: (1) To develop a novel scoring system for the prediction of pathologic fracture in patients with long-bone lesions from multiple myeloma; and (2) to compare the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristic (ROC) area under curve (AUC) between the novel scoring system and the Mirels system.

METHODS

Between 2003 and 2017, 763 patients at one center with the diagnosis of multiple myeloma were reviewed, of whom 174 presented with long-bone disease involvement. Of those, 5% (nine of 174) were missing data or radiographs at a minimum of 1 year and had not reached an endpoint (fracture or surgery) before that time and were therefore excluded. Many patients have more than one lesion; consequently, we used the largest lesion in each patient, resulting in 163 lesions in as many patients. Ten percent (16 of 163) of these patients eventually developed a fracture and 4% (six of 163) underwent prophylactic stabilization (excluded from analysis because of outcome uncertainty). During the study period, prophylactic stabilization was performed at the discretion of the orthopaedic oncologist. Fifty-one percent (83 of 163) of patients were female, and the mean (± SD) age was 60 ± 10 years at radiographic lesion identification. All lesions were characterized before determining whether the patient underwent pathologic fracture. We identified variables associated with pathologic fracture on univariate analysis. Variables independently significant on logistic regression analysis were used to generate scoring algorithms at varying weights and scoring cutoffs for comparison via ROC curves. We then selected a novel score based on ROC performance, and compared the sensitivity, specificity, PPV, and NPV of that scoring system to that of Mirels score. ROC AUCs were compared after bootstrapping 100,000 iterations. Alpha was set at 0.05.

RESULTS

After controlling for potential confounders, such as age, sex, and duration of myeloma diagnosis, we found the following factors were independently associated with the occurrence of pathologic fracture: larger lesion size (area, cm2) (log odds 0.17; p = 0.03), longer lesion latency (years from diagnosis to lesion identification) (log odds 0.25; p = 0.03), presence of pain (relative risk [RR] 2.9; p = 0.04), and metaphyseal location (RR 3.2, compared with epiphyseal or diaphyseal; p = 0.003). These variables were used to formulate a novel scoring system. Compared with the Mirels system, the novel system was more sensitive (69% [95% CI 61 to 76] versus 38% [95% CI 30 to 46]; p < 0.05) but not different in terms of specificity (87% [95% CI 80 to 91] versus 87% [95% CI 81 to 92]; p > 0.05), PPV (37% [95% CI 29 to 45] versus 25% [95% CI 19 to 33]; p > 0.05), NPV (96% [95% CI 91 to 99] versus 92% [95% CI 87 to 96]; p > 0.05), or AUC (0.85 [95% CI 0.74 to 0.92] versus 0.67 [95% CI 0.51 to 0.81]; p > 0.05).

CONCLUSION

The novel scoring system was found to be more sensitive than the Mirels system for predicting pathologic fracture in our retrospective cohort of patients with multiple myeloma-related bone disease. Specificity, PPV, NPV, and ROC AUC were not different with the numbers available. Thus, the novel scoring system may serve as a more effective screening tool to determine which patients with multiple myeloma would benefit from further radiologic or orthopaedic evaluation based on a skeletal survey.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Minimal Pain Decrease Between 2 and 4 Weeks After Nonoperative Management of a Displaced Midshaft Clavicle Fracture Is Associated with a High Risk of Symptomatic Nonunion

BACKGROUND

The main long-term benefit of operative treatment of displaced midshaft clavicular fractures is the reduction in nonunion risk, and as this risk is generally low, the ideal approach would be to operate only patients at high risk of nonunion. However, most current surgical decision models use baseline variables to estimate the nonunion risk, and the value of these models remains unclear. Pain in the early weeks after fracture could be potentially be an indirect measurement of fracture healing, and so it is a potential proxy variable that could lead to simpler prediction models.

QUESTIONS/PURPOSES

(1) Is pain a possible proxy variable for the development of symptomatic nonunion after nonoperative treatment of midshaft clavicular fractures? (2) How reliable is the model we created that uses pain as a proxy variable for symptomatic nonunion of nonoperatively treated clavicle fractures?

METHODS

In this secondary retrospective analysis of an earlier randomized trial, we studied prospectively collected data from 64 nonoperatively treated patients aged 18 years to 60 years. In the original randomized trial, we compared operative and nonoperative treatment of displaced midshaft clavicular fractures. In all, 150 patients were included in the study, of whom 71 received nonoperative treatment. Patients were predominantly males (75%, 48 of 64) with a mean age of 38 ± SD 12 years; most fractures were comminuted and shortened more than 1 cm. All 71 patients who were nonoperatively treated were potentially eligible for this secondary analysis; of those, 11% (8 of 71) were lost to follow-up, leaving 63 patients from the nonoperative treatment arm and one patient from the operative treatment arm (who declined surgical treatment after randomization but was followed in this group according to the intention-to-treat principle) for analysis here. Nonunion was defined as lack of callus formation, persistent fracture lines and/or sclerotic edges of the bones at the fracture site on plain radiographs at 6 months follow-up. Nonunions were regarded as symptomatic if pain, tenderness, and local crepitation were present at the fracture site. Seventeen percent (11 of 64) of patients had symptomatic nonunions. After investigating differences in early pain scores between the union and nonunion groups, we defined the VASratio as the VAS pain score at 4 weeks divided by the VAS pain score at 2 weeks. Week 2 VAS pain score was chosen as baseline after visual inspection of a linear mixed model that showed increased divergence in pain scores between union and nonunion group at 2 weeks after fracture. Week 4 was chosen as the cutoff because we wanted a reasonable time frame for the detection of pain reduction and did not want to delay surgical treatment more than necessary. Odds ratios for various risk factors were calculated using logistic regression analyses. We used a receiver operating characteristic curve analysis to identify cutoff values for the VASratio.

RESULTS

An increase in absolute pain score at 4 weeks after fracture (odds ratio 1.8 per 1 point increase [95% confidence interval 1.1 to 3.4]) was associated with an increased risk of nonunion 6 months after fracture. Likewise, we found that an increasing VASratio (OR 1.02 per 0.01 point increase [95% CI 1.002 to 1.06]) was also associated with nonunion. Receiver operating curve analysis found that the best cutoff value of VASratio was about 0.6. Patients with a VASratio above 0.6 had a relative risk of developing nonunion of 18 (95% CI 2 to 130) compared with patients with a VASratio below 0.6. Sparse-data bias could be present, as is evident from this wide confidence interval, though even at the low end of the confidence interval, the relative risk was 2, which may still improve surgical decision-making.

CONCLUSION

A pain score that exhibits no or minimal change from 2 to 4 weeks after nonoperative treatment of a displaced midshaft fracture of the clavicle is associated with a high risk that symptomatic nonunion will develop. Patients with no or minimal change in pain in the early weeks may be candidates for surgery to reduce the risk of symptomatic nonunion. As this was a retrospective study, with a risk of sparse-data bias, the predictive value of the VASratio needs to be further investigated in large prospective studies before clinical use.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Which Factors Are Associated with Local Control and Survival of Patients with Localized Pelvic Ewing's Sarcoma? A Retrospective Analysis of Data from the Euro-EWING99 Trial

BACKGROUND

Local treatment of pelvic Ewing's sarcoma may be challenging, and intergroup studies have focused on improving systemic treatments rather than prospectively evaluating aspects of local tumor control. The Euro-EWING99 trial provided a substantial number of patients with localized pelvic tumors treated with the same chemotherapy protocol. Because local control included surgical resection, radiation therapy, or a combination of both, we wanted to investigate local control and survival with respect to the local modality in this study cohort.

QUESTIONS/PURPOSES

(1) Do patients with localized sacral tumors have a lower risk of local recurrence and higher survival compared with patients with localized tumors of the innominate bones? (2) Is the local treatment modality associated with local control and survival in patients with sacral and nonsacral tumors? (3) Which local tumor- and treatment-related factors, such as response to neoadjuvant chemotherapy, institution where the biopsy was performed, and surgical complications, are associated with local recurrence and patient survival in nonsacral tumors? (4) Which factors, such as persistent extraosseous tumor growth after chemotherapy or extent of bony resection, are independently associated with overall survival in patients with bone tumors undergoing surgical treatment?

METHODS

Between 1998 and 2009, 1411 patients with previously untreated, histologically confirmed Ewing's sarcoma were registered in the German Society for Pediatric Oncology and Hematology Ewing's sarcoma database and treated in the Euro-EWING99 trial. In all, 24% (339 of 1411) of these patients presented with a pelvic primary sarcoma, 47% (159 of 339) of which had macroscopic metastases at diagnosis and were excluded from this analysis. The data from the remaining 180 patients were reviewed retrospectively, based on follow-up data as of July 2016. The median (range) follow-up was 54 months (5 to 191) for all patients and 84 months (11 to 191) for surviving patients. The study endpoints were overall survival, local recurrence and event-free survival probability, which were calculated with the Kaplan-Meier method and compared using the log-rank test. Hazard ratios (HRs) with their respective 95% CIs were estimated in a multivariate Cox regression model.

RESULTS

Sacral tumors were associated with a reduced probability of local recurrence (12% [95% CI 1 to 22] versus 28% [95% CI 20 to 36] at 5 years, p = 0.032), a higher event-free survival probability (66% [95% CI 51 to 81] versus 50% [95% CI 41 to 58] at 5 years, p = 0.026) and a higher overall survival probability (72% [95% CI 57 to 87] versus 56% [95% CI 47 to 64] at 5 years, p = 0.025) compared with nonsacral tumors. With the numbers available, we found no differences between patients with sacral tumors who underwent definitive radiotherapy and those who underwent combined surgery and radiotherapy in terms of local recurrence (17% [95% CI 0 to 34] versus 0% [95% CI 0 to 20] at 5 years, p = 0.125) and overall survival probability (73% [95% CI 52 to 94] versus 78% [95% CI 56 to 99] at 5 years, p = 0.764). In nonsacral tumors, combined local treatment was associated with a lower local recurrence probability (14% [95% CI 5 to 23] versus 33% [95% CI 19 to 47] at 5 years, p = 0.015) and a higher overall survival probability (72% [95% CI 61 to 83] versus 47% [95% CI 33 to 62] at 5 years, p = 0.024) compared with surgery alone. Even in a subgroup of patients with wide surgical margins and a good histologic response to induction treatment, the combined local treatment was associated with a higher overall survival probability (87% [95% CI 74 to 100] versus 51% [95% CI 33 to 69] at 5 years, p = 0.009), compared with surgery alone.A poor histologic response to induction chemotherapy in nonsacral tumors (39% [95% CI 19 to 59] versus 64% [95% CI 52 to 76] at 5 years, p = 0.014) and the development of surgical complications after tumor resection (35% [95% CI 11 to 59] versus 68% [95% CI 58 to 78] at 5 years, p = 0.004) were associated with a lower overall survival probability in nonsacral tumors, while a tumor biopsy performed at the same institution where the tumor resection was performed was associated with lower local recurrence probability (14% [95% CI 4 to 24] versus 32% [95% CI 16 to 48] at 5 years, p = 0.035), respectively.In patients with bone tumors who underwent surgical treatment, we found that after controlling for tumor localization in the pelvis, tumor volume, and surgical margin status, patients who did not undergo complete (defined as a Type I/II resection for iliac bone tumors, a Type II/III resection for pubic bone and ischium tumors and a Type I/II/III resection for tumors involving the acetabulum, according to the Enneking classification) removal of the affected bone (HR 5.04 [95% CI 2.07 to 12.24]; p < 0.001), patients with a poor histologic response to induction chemotherapy (HR 3.72 [95% CI 1.51 to 9.21]; p = 0.004), and patients who did not receive additional radiotherapy (HR 4.34 [95% CI 1.71 to 11.05]; p = 0.002) had a higher risk of death. The analysis suggested that the same might be the case in patients with a persistent extraosseous tumor extension after induction chemotherapy (HR 4.61 [95% CI 1.03 to 20.67]; p = 0.046), although the wide CIs pointing at a possible sparse-data bias precluded any definitive conclusions.

CONCLUSION

Patients with sacral Ewing's sarcoma appear to have a lower probability for local recurrence and a higher overall survival probability compared with patients with tumors of the innominate bones. Our results seem to support a recent recommendation of the Scandinavian Sarcoma Group to locally treat most sacral Ewing's sarcomas with definitive radiotherapy. Combined surgical resection and radiotherapy appear to be associated with a higher overall survival probability in nonsacral tumors compared with surgery alone, even in patients with a wide resection and a good histologic response to neoadjuvant chemotherapy. Complete removal of the involved bone, as defined above, in patients with nonsacral tumors may be associated with a decreased likelihood of local recurrence and improved overall survival. Persistent extraosseous tumor growth after induction treatment in patients with nonsacral bone tumors undergoing surgical treatment might be an important indicator of poorer overall survival probability, but the possibility of sparse-data bias in our cohort means that this factor should first be validated in future studies.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Patients with a History of Treated Septic Arthritis are at High Risk of Periprosthetic Joint Infection after Total Joint Arthroplasty

BACKGROUND

In patients undergoing total joint arthroplasty (TJA), increasing attention has been directed recently toward identifying specific patient-related risk factors that may predispose patients to periprosthetic joint infection (PJI). Currently, it is unclear whether having a history of a treated native septic arthritis is a risk factor for PJI after TJA in the same joint. Previous studies have reported contradictory evidence and results varied between a substantially higher rates of PJIs to very low or no reported PJIs.

QUESTIONS/PURPOSES

(1) What is the risk of PJI in patients who received TJA and had a history of treated same-joint native joint septic arthritis and (2) What are the associated risk factors for these patients developing PJI?

METHODS

This was a multicenter retrospective analysis of patients who received primary THA or TKA between January 2000 and December 2016 and who had a history of treated native joint septic arthritis in the same joint. Patients were included in the study only if they were considered to have resolved their joint infection based on a preoperative evaluation that included: (1) the absence of clinical symptoms and signs of active infection or local joint inflammation, (2) recent plain radiographs showing only advanced degenerative changes without evidence of active osteolysis or bone infection, (3) preoperative laboratory investigations for infection, including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and total leukocyte counts within normal ranges. Patients were reviewed for the occurrence of postoperative PJI. The final cohort included 62 patients who had a mean followup of 4.4 years (range, 3 months-17 years) from the time of TJA. A total of 21 patients (34%) had less than 2 years of followup, including six (10%) mortalities. In total, eight patients (13%) died during the study period, none of which were due to PJI. Patient characteristics, time interval from treatment of septic arthritis to TJA, and Charlson comorbidity index adjusted for age were collected. We used a Kaplan-Meier analysis to estimate the overall survivorship among all TJAs as well as those who underwent THA versus TKA, and we performed a statistical comparison using the Mantel-Cox log-rank test. We performed a Cox regression hazard ratio (HR) survival analysis to identify risk factors for PJI. The PJI odds ratios (OR) for patients who underwent TJA within 2 years of septic arthritis were calculated as an additional temporal analysis.

RESULTS

In patients with a history of treated same-joint native septic arthritis, the proportion of PJI was five of 62 patients (8%). The Kaplan-Meier analysis demonstrated an overall survivorship free from PJI of 92% at 14.5 ± 1.14 years (95% confidence interval [CI] = 12.3-16.8 years). All PJI cases occurred only in patients who underwent TKA, which when analyzed separately, yielded a survivorship of 85% at 10.5 ± 0.9 years (95% CI = 8.7-12.3 years) versus 100% in patients who underwent THA (p = 0.068). Mean time to PJI occurrence was 10 months (range, 2-20 months). After controlling for relevant confounding variables, such as age, sex, affected joint and comorbidities, we found smoking (HR, 8.06; 95% CI, 1.33-48.67; p = 0.023) to be associated with increased risk for PJI development.

CONCLUSION

Patients with history of native joint infections are at higher risk of PJI, especially smokers. Despite our limitations, this study suggests careful assessment of several other factors in these patients, including allowing a minimum interval of 2 years from the time of resolving native joint septic arthritis to TJA. Patients who are undergoing TKA seem to be more prone to the PJI risk and may benefit from more aggressive planning. In addition, medical optimization of comorbidities that may confer additional risk, such as diabetes, become exceptionally important in these patients.

LEVEL OF EVIDENCE

Level III, therapeutic study.