Uma Srikumaran

Patterns of Pediatric Supracondylar Humerus Fractures

Purpose: The Wilkins-modified Gartland classification of pediatric supracondylar humerus fractures does not consider coronal or sagittal obliquity. The purposes of our study were (1) to identify and describe fracture characteristics with unique properties and (2) to propose a fracture classification system that can be reproduced reliably. Methods: We retrospectively studied 203 consecutive displaced pediatric extension-type supracondylar humerus fractures treated operatively from January 1998 to January 2003. Fracture characteristics (eg, coronal and sagittal obliquity, postoperative alignment), type of surgical treatment, outcome, and complications were assessed and analyzed statistically with Student t test and a receiver operating characteristic curve. Significance was defined as P < 0.05. We incorporated significant cutoff values for fracture obliquity into our classification scheme and tested the classifications interobserver and intraobserver reliability. Results: We identified 4 coronal (typical transverse, medial oblique, lateral oblique, and high fractures) and 2 sagittal (low sagittal and high sagittal) subtypes with significantly different characteristics and outcome. Compared with fractures with coronal obliquity of less than 10 degrees, fractures with coronal obliquity of 10 degrees or greater were associated with significantly more comminution and rotational malunion. Compared with fractures with sagittal obliquity of less than 20 degrees, fractures with sagittal obliquity of 20 degrees or greater were associated with a significantly higher incidence of additional injuries and were more likely to result in extension malunion. Analysis of the interobserver and intraobserver reliability for our system identified correlation coefficients ranging from 0.772 to 0.907 and 0.860 to 0.899, respectively. Conclusions: Because pediatric extension-type supracondylar humerus fractures vary significantly in terms of characteristics, identification of sagittal oblique and coronal oblique angles may have an important role in surgical decision making and may impact outcomes. Level of Evidence: Level 3 (retrospective study).

Reliability and Validity of 3 Methods of Assessing Orthopedic Resident Skill in Shoulder Surgery.

OBJECTIVE Traditional measures for evaluating resident surgical technical skills (e.g., case logs) assess operative volume but not level of surgical proficiency. Our goal was to compare the reliability and validity of 3 tools for measuring surgical skill among orthopedic residents when performing 3 open surgical approaches to the shoulder. METHODS A total of 23 residents at different stages of their surgical training were tested for technical skill pertaining to 3 shoulder surgical approaches using the following measures: Objective Structured Assessment of Technical Skills (OSATS) checklists, the Global Rating Scale (GRS), and a final pass/fail assessment determined by 3 upper extremity surgeons. Adverse events were recorded. The Cronbach α coefficient was used to assess reliability of the OSATS checklists and GRS scores. Interrater reliability was calculated with intraclass correlation coefficients. Correlations among OSATS checklist scores, GRS scores, and pass/fail assessment were calculated with Spearman ρ. Validity of OSATS checklists was determined using analysis of variance with postgraduate year (PGY) as a between-subjects factor. Significance was set at p < 0.05 for all tests. RESULTS Criterion validity was shown between the OSATS checklists and GRS for the 3 open shoulder approaches. Checklist scores showed superior interrater reliability compared with GRS and subjective pass/fail measurements. GRS scores were positively correlated across training years. The incidence of adverse events was significantly higher among PGY-1 and PGY-2 residents compared with more experienced residents. CONCLUSION OSATS checklists are a valid and reliable assessment of technical skills across 3 surgical shoulder approaches. However, checklist scores do not measure quality of technique. Documenting adverse events is necessary to assess quality of technique and ultimate pass/fail status. Multiple methods of assessing surgical skill should be considered when evaluating orthopedic resident surgical performance.

Enhanced biomechanical stiffness with large pins in the operative treatment of pediatric supracondylar humerus fractures.

Background: Various pin configurations have been recommended for the treatment of supracondylar humerus fractures on the basis of the choice between stability versus the risk of iatrogenic nerve injury. However, little attention has been paid to pin size. The purpose of this study was to evaluate the stability of large (2.8 mm or 0.110 inch) and small (1.6 mm or 0.062 inch) pin constructs in 6 configurations. Methods: A transverse fracture pattern was created by sectioning synthetic humeri in the midolecranon fossa. The specimens were then reduced and pinned in one of 6 configurations: 2 small pins (Kirschner wires) placed crossed or lateral divergent, 2 large pins (Steinmann pins) placed crossed or lateral divergent, or 3 small pins placed crossed or lateral divergent. All specimens were then tested in sagittal extension bending. We investigated the effect of pin configuration and cycle on the sagittal stiffness using multiple linear regression. Results: The 2 small lateral divergent pin configuration was significantly less stable than small crossed pins and large pins in a crossed or a lateral configuration. The addition of a third (lateral) pin to the small crossed pin construct made it significantly less stable than 2 large crossed pins. Although the stability between the remaining configurations was not significantly different, the 2 large crossed pins required the greatest torque to rotate the fragment 20 degrees. There was a significant reduction in torque as a function of cycle, suggesting a loss of fixation during cycling (P<0.05). Conclusions: Large pins (2.8 mm) in any configuration and the placement of small pins (1.6 mm) in a crossed configuration provided more stable reduction in sagittal extension bending than did the conventional 2 small pins in a lateral divergent pin configuration. The most stable configurations involve crossing the medial and lateral pins. Clinical Relevance: There are more stable options than the traditional 2 small lateral pin configuration for fixation of unstable supracondylar fractures. The addition of a third pin is not always advantageous.

Anchored Transosseous-Equivalent Versus Anchorless Transosseous Rotator Cuff Repair: A Biomechanical Analysis in a Cadaveric Model

Background: The original approach for the repair of torn rotator cuffs involved an open technique with sutures passing through the greater tuberosity and tendon. The development of suture anchors allowed for an all-arthroscopic approach with anchor configurations attempting to re-create a transosseous fixation pattern. Presently, an arthroscopic approach can be combined with a transosseous suture configuration without using anchors. Purpose: To evaluate cyclic loading, ultimate load to failure, and the failure mechanisms of transosseous-equivalent (TOE) repair with anchors and anchorless transosseous (AT) repair of rotator cuff tears. Study Design: Controlled laboratory study. Methods: Supraspinatus tears (25 mm) were created in 20 fresh-frozen, human cadaveric shoulders, which were randomized to TOE or AT repair (10 in each group, paired experimental design). Biomechanical testing was performed with an initial preload, cyclic loading, and load to failure. Optical markers were used to monitor gap formation in 3 planes, and the failure mode was recorded. Paired t tests were used to make comparisons of biomechanical parameters between the groups. Multinomial logistic regression was used to compare failure modes between the groups. Significance was set to .05. Results: The TOE group had a significantly higher mean (±SD) ultimate failure load (578.5 ± 123.8 N) than the AT group (468.7 ± 150.9 N) (P = .034). The TOE group also had a significantly less mean first-cycle excursion (2.97 ± 1.97 mm) than the AT group (4.70 ± 2.04 mm) (P = .046). There were no significant differences between the groups in cyclic elongation or linear stiffness during cyclic loading. Primary modes of failure were a type 2 tendon tear with medial tendon disruption in the TOE group (7/10) and a type 1 tendon tear with lateral tendon disruption in the AT group (6/10). Conclusion: TOE repair resulted in a significantly higher mean failure load compared with AT repair in a cadaveric model. The most common modes of failure were a type 2 tendon tear in the TOE group and a type 1 tendon tear in the AT group. Clinical Relevance: A higher mean failure load in TOE versus AT constructs may come at the cost of a less favorable failure mode adjacent to medial anchors at the musculotendinous junction, potentially making revision difficult.

Clinical Assessment of the Dynamic Labral Shear Test for Superior Labrum Anterior and Posterior Lesions

Background: Diagnosing superior labrum anterior and posterior (SLAP) lesions through physical examination remains challenging. The dynamic labral shear test (DLST) has been shown to have likelihood ratios (LRs) of 31.6 and 1.1 for diagnosing SLAP lesions. Purpose: To determine the clinical utility of the DLST for diagnosing SLAP lesions. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: This prospective, consecutive case series included 774 patients who underwent diagnostic arthroscopy and a preoperative DLST between 2007 and 2013. Patients were divided into 3 groups: 610 control patients with no SLAP lesion but with other abnormalities, 9 patients with isolated SLAP lesion (ISL), and 155 patients with concomitant SLAP lesion (CSL), who had a SLAP lesion and another shoulder abnormality. We determined sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), odds ratio (OR), and diagnostic accuracy (DA) of the DLST with and without other tests. Results: The DLST was positive for 242 of 610 controls (40%), 7 of 9 patients (78%) in the ISL group, and 88 of 155 patients (57%) in the CSL group. In the ISL group, the DLST had a sensitivity of 78%, specificity of 51%, PPV of 2%, NPV of 100%, OR of 3.58, and DA of 51%. In comparison, the ORs were 1.09 for the active compression test, 1.30 for the lift-off test, and 1.53 for the relocation test, which were not significantly different from each other. For diagnosing a SLAP lesion existing in a joint with other associated injury, the DLST had a sensitivity of 57%, specificity of 52%, PPV of 23%, NPV of 83%, OR of 1.4, and DA of 53%. Combining all 4 tests did not improve the OR for detecting ISLs or CSLs. Conclusion: The DLST is sensitive but not specific for detecting ISLs. With an OR of 3.58, the DLST is useful for diagnosing ISLs. However, in patients who have CSLs, the DLST is not as useful for diagnosing SLAP lesions.

Value and health care policy ramifications of rotator cuff repair

The societal burden of rotator cuff disease continues to increase with the aging of our population. Rotator cuff repairs have also become increasingly common over the last 2 decades. In our current cost conscious health care environment it is imperative to understand the value delivered to patients by various interventions. Value is most often equated with outcomes relative to the costs associated with care. To determine the value of different interventions, a thorough understanding of how to measure and interpret patient outcomes is crucial. In addition, calculating costs can be complex and physicians are often unaware of the costs related to their own decisions. Despite the complexities of measuring value, its benefits include heightened transparency in health care delivery, aligning stakeholders, and avoiding the trap of focussing solely on cost reductions, which may endanger effective treatment modalities.

Pullout strength of standard vs. cement-augmented rotator cuff repair anchors in cadaveric bone

Background: We evaluate a novel method of rotator cuff repair that uses arthroscopic equipment to inject bone cement into placed suture anchors. A cadaver model was used to assess the pullout strength of this technique versus anchors without augmentation. Methods: Six fresh‐frozen matched pairs of upper extremities were screened to exclude those with prior operative procedures, fractures, or neoplasms. One side from each pair was randomized to undergo standard anchor fixation with the contralateral side to undergo anchor fixation augmented with bone cement. After anchor fixation, specimens were mounted on a servohydraulic testing system and suture anchors were pulled at 90° to the insertion to simulate the anatomic pull of the rotator cuff. Sutures were pulled at 1 mm/s until failure. Findings: The mean pullout strength was 540 N (95% confidence interval, 389 to 690 N) for augmented anchors and 202 N (95% confidence interval, 100 to 305 N) for standard anchors. The difference in pullout strength was statistically significant (P < 0.05). Interpretation: This study shows superior pullout strength of a novel augmented rotator cuff anchor technique. The described technique, which is achieved by extruding polymethylmethacrylate cement through a cannulated in situ suture anchor with fenestrations, significantly increased the ultimate failure load in cadaveric human humeri. This novel augmented fixation technique was simple and can be implemented with existing instrumentation. In osteoporotic bone, it may substantially reduce the rate of anchor failure.

Biomechanical Strength of Rotator Cuff Repairs: A Systematic Review and Meta-regression Analysis of Cadaveric Studies:

Background: Biomechanical cadaveric studies of rotator cuff repair (RCR) have shown that transosseous equivalent and double-row anchored repairs are stronger than other repair constructs. Purpose: To identify technical and procedural parameters that most reliably predict biomechanical performance of RCR constructs. Study Design: Systematic review. Methods: The authors systematically searched the EMBASE and PubMed databases for biomechanical studies that measured RCR performance in cadaveric specimens. The authors performed a meta-regression on the pooled data set with study outcomes (gap formation, failure mode, and ultimate failure load) as dependent variables and procedural parameters (eg, construct type, number of suture limbs) as covariates. Stratification by covariates was performed. An alpha level of .05 was used. Results: Data from 40 eligible studies were included. Higher number of suture limbs correlated with higher ultimate failure load (β = 38 N per limb; 95% CI, 28 to 49 N) and less gap formation (β = −0.6 mm per limb; 95% CI, −1 to −0.2 mm). Other positive predictors of ultimate failure load were number of sutures, number of mattress stitches, and use of wide suture versus standard suture. When controlling for number of suture limbs, we found no significant differences among single-row anchored, double-row anchored, transosseous equivalent, and transosseous repairs. Higher number of suture limbs and transosseous equivalent repair both increased the probability of catastrophic construct failure. Conclusion: This study suggests that the number of sutures, suture limbs, and mattress stitches in a RCR construct are stronger predictors of overall strength than is construct type. There is a need to balance increased construct strength with higher risk of type 2 failure.

Pullout strength of cement-augmented and wide-suture transosseous fixation in the greater tuberosity

Background: Obtaining strong fixation in low‐density bone is increasingly critical in surgical repair of rotator cuff tears because of the aging population. To evaluate two new methods of improving pullout strength of transosseous rotator cuff repair in low‐density bone, we analyzed the effects of 1) using 2‐mm suture tape instead of no. 2 suture and 2) augmenting the lateral tunnel with cement. Methods: Eleven pairs of osteopenic or osteoporotic cadaveric humeri were identified by dual‐energy x‐ray absorptiometry. One bone tunnel and one suture were placed in the heads of 22 specimens. Five randomly selected pairs were repaired with no. 2 suture; the other six pairs were repaired with 2‐mm suture tape. One side of each pair received lateral tunnel cement augmentation. Specimens were tested to suture pullout. Data were fitted to multivariate models that accounted for bone mineral density and other specimen characteristics. Findings: Two specimens were excluded because of knot‐slipping during testing. Use of suture tape versus no. 2 suture conferred a 75‐N increase (95% CI: 37, 113) in pullout strength (P < 0.001). Cement augmentation conferred a 42‐N improvement (95% CI: 10, 75; P = 0.011). Other significant predictors of pullout strength were age, sex, and bone mineral density. Interpretation: We show two methods of improving the fixation strength of transosseous rotator cuff repairs in low‐density bone: using 2‐mm suture tape instead of no. 2 suture and augmenting the lateral tunnel with cement. These methods may improve the feasibility of transosseous repairs in an aging patient population. HighlightsTwo methods of improving transosseous rotator cuff repair strength were evaluated.Load‐to‐failure testing was performed on 22 cadaveric humeri with low bone density.Suture type and cement augmentation both significantly affected pullout strength.