Validation of varus stress radiographs for anterior cruciate ligament and posterolateral corner knee injuries: A biomechanical study.

PURPOSE: The purpose of this study was to determine the effect of isolated anterior cruciate ligament (ACL) insufficiency on the radiographic varus stress test, and to provide reference data for the increase in lateral compartment opening under varus stress for a combined ACL and PLC injury. METHODS: Ten cadaveric lower extremities were fixed to a jig in 20° of knee flexion. Twelve Newton-meter (Nm) and clinician-applied varus loads were tested, first with intact knee ligaments, followed by sequential sectioning of the ACL, fibular collateral ligament (FCL), popliteus tendon and the popliteofibular ligament (PFL). Lateral compartment opening was measured after each sequential sectioning. RESULTS: Maximum increase in lateral compartment opening for an isolated ACL deficient knee was 1.06mm with mean increase of 0.52mm (p=0.021) for the clinician-applied load. Mean increase in lateral compartment opening in an ACL and FCL deficient knee compared to the intact knee was 1.48mm (p<0.005) and 1.99mm (p<0.005) for the 12-Nm and clinician-applied loads, respectively, increasing to 1.94mm (p<0.005) and 2.68mm (p<0.005) with sectioning of the ACL and all PLC structures. CONCLUSIONS: Anterior cruciate ligament deficiency contributes to lateral compartment opening on varus stress radiographs though not sufficiently to confound previously established standards for lateral ligament knee injuries. We did not demonstrate the same magnitude of lateral compartment opening with sectioning of the PLC structures as previously reported, questioning the reproducibility of varus stress radiographic testing among institutions. Clinicians are cautioned against making surgical decisions based solely on current standards for radiographic stress examinations.

Incidence of knee sepsis after ACL reconstruction at one institution: the impact of a clinical pathway.

BACKGROUND: After experiencing an unusually high incidence of knee sepsis after anterior cruciate ligament (ACL) reconstruction, we sought to (1) describe how we resolved this problem through temporary discontinuation of the procedure, formation of a multidisciplinary ACL Task Force, systematic investigation of clinical data and institutional care practices, and development and implementation of an evidence-based ACL Clinical Pathway (the Pathway); and (2) report our findings and results. METHODS: From 1999 through 2008, thirty-seven cases of knee sepsis after ACL reconstruction were recorded at our institution. In 2008 (yearly incidence, 4.4%), ACL reconstructions were temporarily suspended and a Task Force was assembled to (1) identify infection risk factors or epidemiological links among cases, (2) inspect environment and processes for possible infection sources, and (3) update existing perioperative practices according to current evidence-based guidelines to reduce surgical site infection risk. These actions led to the development of the Pathway for patients and providers. The rates of knee sepsis before and after the Pathway was implemented were compared. RESULTS: There was no consistent risk factor or epidemiologic link among the cases of knee sepsis other than the time and place of the ACL reconstruction. Process review identified shortfalls in decontamination and sterilization of some surgical equipment. Perioperative care practices review revealed wide interprovider variation. Pathway implementation reduced the rate of knee sepsis after ACL reconstruction from 1.96% (twenty-four cases after 1226 ACL reconstructions performed from 2002 to 2008) to 0% (zero cases after 500 ACL reconstructions performed from 2008 to 2011); the difference was significant (p = 0.003). CONCLUSIONS: When a Task Force investigation suggested that knee sepsis after ACL reconstruction was a multifactorial problem, we implemented and standardized evidence-based perioperative care practices via the institution-wide Pathway, which significantly improved the quality and consistency of care for patients undergoing ACL reconstruction, as well evidenced by the elimination of knee sepsis.

Analysis and comparison of the biomechanical properties of univalved and bivalved cast models.

PURPOSE: Fiberglass casts are frequently valved to relieve the pressure associated with upper extremity swelling after a surgical procedure or when applied after reduction of a displaced fracture in a child. Although different opinions exist regarding the valving of casts, no research to date has explored the biomechanical effects of this commonly used technique. As cast integrity is essential for the maintenance of fracture reduction, it is important to understand whether casts are structurally compromised after valving. Understanding the effects of valving on cast integrity may help guide clinicians in the technique of valving while minimizing the potential for a loss of fracture reduction. METHODS: Thirty standardized cylindrical fiberglass cast models were created. Ten models were left intact, 10 were univalved, and 10 were bivalved. All the models were mechanically tested by a 3-point bending apparatus secured to a biaxial materials testing system. Load to failure and bending stiffness were recorded for each sample. Differences in load of failure and bending stiffness were compared among the groups. RESULTS: Unvalved cast models had the highest failure load and bending stiffness, whereas bivalved casts showed the lowest value for both failure load and bending stiffness. Univalved casts had a failure load measured to be between those of unvalved and bivalved cast models. Analysis of variance showed significance when failure load and bending stiffness data among all the groups were compared. A post hoc Bonferroni statistical analysis showed significance in bending stiffness between intact and bivalved models (P < 0.01), intact and univalved models (P < 0.01), but no significant difference in bending stiffness between univalved and bivalved models (P > 0.01). Differences in measured failure load values were found to be statistically significant among all cast models (P < 0.01). CONCLUSIONS: Valving significantly decreases the bending stiffness and load to failure of fiberglass casts. Univalved casts have a higher load to failure than bivalved casts. CLINICAL RELEVANCE: Valving adversely alters the structural integrity of fiberglass casts. This may impair a cast's ability to effectively immobilize an extremity or maintain a fracture reduction.

Plantar flexion influences radiographic measurements of the ankle mortise.

BACKGROUND: The treatment of ankle fractures often depends on the integrity of the deltoid ligament. Diagnosis of a deltoid ligament tear depends on the measurement of the medial clear space. We sought to evaluate the impact of ankle plantar flexion on the medial clear space. METHODS: Mortise radiographs were made for twenty-five healthy volunteers, with the ankle in four positions of plantar flexion (0 degrees, 15 degrees, 30 degrees, and 45 degrees). Four observers measured the medial clear space and the superior clear space on each radiograph. The mean medial clear space at 0 degrees was defined as the control, and the deviation of the medial clear space from the control value was calculated at 15 degrees, 30 degrees, and 45 degrees of plantar flexion. The ratio of the medial clear space to the superior clear space was determined on all radiographs, and ratios that were false-positive for a deltoid ligament injury were identified. RESULTS: Fourteen male and eleven female volunteers were evaluated. The average increase in the medial clear space when ankle plantar flexion was increased from 0 degrees to 45 degrees was 0.38 mm (95% confidence interval, 0.18 to 0.58 mm). This increase was significant (p = 0.005). The average increase in the medial clear space was 0.04 mm when ankle plantar flexion was increased from 0 degrees to 15 degrees and 0.22 mm when it was increased from 0 degrees to 30 degrees. Neither of these changes was significant (p = 0.99 and 0.20). The prevalence of false-positive findings of deltoid injury based on the ratio of the medial clear space to the superior clear space increased as ankle plantar flexion increased, but this increase did not reach significance in our study group (p = 0.18). CONCLUSIONS: Plantar flexion of the ankle produces changes in radiographic measurements of the medial clear space. The potential for false-positive findings of deltoid disruption increases with increasing ankle plantar flexion.

Displaced apophyseal olecranon fracture in a healthy child.

Olecranon apophyseal fractures in children are uncommon. The bulk of these injuries are nondisplaced and therefore can be treated nonoperatively. Few published reports of children with displaced fractures of the olecranon apophysis exist, and the large majority of reports describe children with osteogenesis imperfecta. We report our experience with the case of an 11-year-old, healthy, male patient without osteogenesis imperfecta who sustained a displaced olecranon apophyseal fracture during a fall.

Long-term evaluation of the Roux-Elmslie-Trillat procedure for patellar instability: a 26-year follow-up.

BACKGROUND: Few published articles exist reporting the long-term evaluation of the Roux-Elmslie-Trillat procedure. PURPOSE: To assess the long-term effect of the Roux-Elmslie-Trillat procedure in preventing recurrent subluxation and dislocation of the patella. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Eighteen patients who underwent the Roux-Elmslie-Trillat procedure for dislocation or subluxation of the patella were identified from a group previously evaluated at a mean follow-up of 3 years. The prevalence of recurrent subluxation or dislocation at a mean follow-up of 26 years was compared with the prevalence reported at the mean follow-up of 3 years. Although not the focus of this study, Cox functional scores were obtained from the smaller group and compared with the results at the 3-year follow-up. RESULTS: Seven percent (95% confidence interval, 0.00-0.32) of the patients had recurrent subluxation at 26 years compared with 7% (95% confidence interval, 0.03-0.13) of the study population reported at 3 years (P = 1.00). Fifty-four percent (95% confidence interval, 0.27-0.79) rated their affected knee as good or excellent at 26 years compared with 73% (95% confidence interval, 0.64-0.81) of the larger study population reported at 3 years (P = .14). CONCLUSION: The prevalence of recurrent subluxation and dislocation in patients with patellofemoral malalignment who underwent the Roux-Elmslie-Trillat procedure for dislocation or subluxation of the patella is similar at 3 and 26 years after the procedure. The long-term functional status of the affected knee in patients who underwent the Roux-Elmslie-Trillat procedure declined.