How Effective Are Noninvasive Tests for Diagnosing Malignant Peripheral Nerve Sheath Tumors in Patients with Neurofibromatosis Type 1? Diagnosing MPNST in NF1 Patients.

BACKGROUND: Distinguishing between benign and malignant peripheral nerve sheath tumors (MPNSTs) in neurofibromatosis 1 (NF1) patients prior to excision can be challenging. How can MPNST be most accurately diagnosed using clinical symptoms, magnetic resonance imaging (MRI) findings (tumor size, depth, and necrosis), positron emission tomography (PET) measures (SUVpeak, SUVmax, SUVmax tumor/SUVmean liver, and qualitative scale), and combinations of the above? Methods. All NF1 patients who underwent PET imaging at our institution (January 1, 2007-December 31, 2016) were included. Medical records were reviewed for clinical findings; MR images and PET images were interpreted by two fellowship-trained musculoskeletal and nuclear medicine radiologists, respectively. Receiver operating characteristic (ROC) curves were created for each PET measurement; the area under the curve (AUC) and thresholds for diagnosing malignancy were calculated. Logistic regression determined significant predictors of malignancy. RESULTS: Our population of 41 patients contained 34 benign and 36 malignant tumors. Clinical findings did not reliably predict MPNST. Tumor depth below fascia was highly sensitive; larger tumors were more likely to be malignant but without a useful cutoff for diagnosis. Necrosis on MRI was highly accurate and was the only significant variable in the regression model. PET measures were highly accurate, with AUCs comparable and cutoff points consistent with prior studies. A diagnostic algorithm was created using MRI and PET findings. CONCLUSIONS: MRI and PET were more effective at diagnosing MPNST than clinical features. We created an algorithm for preoperative evaluation of peripheral nerve sheath tumors in NF1 patients, for which additional validation will be indicated.

Prospective outcomes of young and middle-aged adults with medial compartment osteoarthritis treated with a proximal tibial opening wedge osteotomy.

PURPOSE: The purpose of this study was to conduct a prospective outcome analysis of proximal tibial opening wedge osteotomies performed in young and middle-aged patients (aged <55 years) for the treatment of symptomatic medial compartment osteoarthritis of the knee. METHODS: A consecutive series of young and middle-aged adults who underwent proximal tibial opening wedge osteotomies for symptomatic medial compartment osteoarthritis and genu varus alignment were prospectively followed up. Patients were evaluated with preoperative and postoperative modified Cincinnati Knee Scores and International Knee Documentation Committee objective knee subscores for knee effusions and the single-leg hop. Calculations were made of the preoperative and postoperative long-leg radiographic mechanical weight-bearing axis, patellar height (Insall-Salvati index), and tibial slope. A separate cohort of asymptomatic patients was used to quantify tibial plateau anatomy to provide an objective description of the lower extremity mechanical axis. RESULTS: There were 47 patients, with a mean age of 40.5 years, with a minimum of 2 years' follow-up, who formed this patient cohort. Modified Cincinnati Knee Scores improved significantly from 42.9 preoperatively to 65.1 at a mean of 3.6 years of follow-up. Radiographic analysis of a separate cohort showed the medial tibial eminence to be located at the 41% point along the tibial plateau from medial (0%) to lateral (100%). There was a significant improvement in malalignment: the mean mechanical axis passed through the tibial plateau at 23% of the distance along the proximal tibia preoperatively versus 54% postoperatively. The Insall-Salvati index decreased from 1.03 to 0.95 (P < .05), and posterior tibial slope increased from 9.4° to 11.7° (P < .05). Of the osteotomies, 3 (6%) were considered failures, defined by revision of the osteotomy or conversion to total knee arthroplasty. CONCLUSIONS: Performing proximal tibial opening wedge osteotomies to treat symptomatic medial compartment osteoarthritis in carefully selected patients leads to a significant improvement in subjective and objective clinical outcome scores with correction of malalignment at a mean of 3.6 years postoperatively. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Isolated and combined grade-III posterior cruciate ligament tears treated with double-bundle reconstruction with use of endoscopically placed femoral tunnels and grafts: operative technique and clinical outcomes.

BACKGROUND: A variety of techniques have been developed to improve clinical outcomes and objective knee stability following posterior cruciate ligament (PCL) reconstruction. Additional refinements in surgical and rehabilitation techniques are necessary for improvement of both subjective and objective outcomes. METHODS: All patients studied underwent endoscopic PCL reconstruction with a double-bundle allograft. All of the allografts were placed into the femoral tunnel through a lateral arthroscopic portal, secured by an all-inside method, and were passed distally through a transtibial tunnel. Modified Cincinnati subjective and International Knee Documentation Committee (IKDC) subjective and objective outcome scores and posterior stress radiographs of the knee were made preoperatively and at the time of final follow-up. RESULTS: There were a total of thirty-nine patients, including thirty-three male and six female patients, with an average age of thirty-three years. There were seven isolated PCL reconstructions and thirty-two combined reconstructions of the knee. Eight patients were not available for follow-up at a minimum of two years, leaving a cohort of thirty-one patients. Preoperative Cincinnati and IKDC subjective scores averaged 34.5 and 39.3, respectively. These scores improved significantly to 73.2 and 74.3, respectively, at an average of 2.5 years postoperatively. On posterior stress radiographs, the average posterior tibial translation of the knees was 15 mm preoperatively and improved significantly to 0.9 mm postoperatively. CONCLUSIONS: Patients undergoing double-bundle PCL reconstruction with use of endoscopic placement of femoral tunnels had significant improvements in subjective and objective outcome scores and with objective knee stability.

Fibular collateral ligament anatomical reconstructions: a prospective outcomes study.

BACKGROUND: After the development and biomechanical validation of an anatomical fibular collateral ligament reconstruction using a semitendinosus graft, this technique has subsequently been applied clinically. HYPOTHESIS: An anatomical reconstruction of a grade III fibular collateral ligament tear using a semitendinosus graft restores the knee to near-normal lateral compartment stability and results in improved patient outcomes. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A prospective study of 20 patients with an average age of 24 years (range, 16-45 years) who had an anatomical reconstruction of the fibular collateral ligament using a semitendinosus graft was performed. All patients were preoperatively and postoperatively evaluated with the modified Cincinnati and International Knee Documentation Committee (IKDC) subjective scoring systems, with the IKDC objective subscores for lateral and posterolateral knee stability and with varus stress radiographs. The patients were followed for an average of 2 years. RESULTS: Sixteen patients were available for follow-up. Six of the patients had an isolated fibular collateral ligament reconstruction. The average preoperative modified Cincinnati score was 28.2, and the average IKDC subjective score was 34.7. Postoperatively, there was a significant improvement of both the modified Cincinnati score (to 88.5) and the IKDC subjective outcome score (to 88.1). The Cincinnati component symptom and functional subscores were also evaluated. The average preoperative symptom subscore was 9.1 and the functional subscore was 19.1. Postoperatively, there was a significant improvement in both scores; symptom subscores improved to 43.0 and functional subscores improved to 45.5. Preoperative varus stress radiographs demonstrated an average differential of 3.9 mm (range, 2.5-6.2 mm) of lateral compartment gapping between the injured and noninjured knee. At an average of 2 years postoperatively, varus stress radiographs demonstrated an average side-to-side lateral compartment gap differential of -0.4 mm. CONCLUSION: An anatomical fibular collateral ligament reconstruction using a semitendinosus graft results in improved patient outcomes and near-normal lateral compartment stability in patients with grade III injuries of the fibular collateral ligament.

A prospective outcomes study of meniscal allograft transplantation.

BACKGROUND: Symptomatic early-onset chondromalacia often develops after a meniscectomy in the affected knee compartment. The role of meniscal transplantation in reducing pain and improving function in patients with prior ipsilateral meniscectomy is still being defined. HYPOTHESIS: Patients with symptomatic early-onset chondromalacia of the knee after ipsilateral meniscectomy will have improved clinical outcomes after meniscal transplantation. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: All patients who underwent meniscal allograft transplantation between July 2003 and December 2006 were prospectively followed. The indications for surgery were unicompartmental knee pain and postactivity effusions after total or near-total meniscectomy in patients with closed physes. High-field magnetic resonance imaging (1.5-T or 3-T magnets) was used to assess the articular cartilage of the affected compartment. The meniscal transplantations were performed with an arthroscopically assisted technique. Modified Cincinnati knee and International Knee Documentation Committee (IKDC) subjective and IKDC objective outcome scores were obtained on all patients preoperatively and postoperatively to evaluate patients' outcomes. RESULTS: Forty patients with an average age of 25 years and a body mass index of 25.4 were included. After an average final follow-up of 2.5 years, IKDC subjective scores increased significantly from 54.5 to 72.0 (P < .001). Modified Cincinnati knee scores increased from 55.2 to 75.3 (P < .001). The preoperative IKDC objective scores measuring effusion improved significantly from 6 A (normal), 29 B (nearly normal), and 5 C (abnormal), when compared with the postoperative scores of 33 A (normal) and 1 B (nearly normal) (P < .01). Five patients sustained tears of their meniscal transplants and underwent partial meniscectomies of the transplant graft. CONCLUSION: The results confirm that meniscal transplantation significantly reduces pain, decreases activity-related effusions, and improves function in patients with prior meniscectomy; however, the long-term chondroprotective effects remain unknown.

Intra-articular lateral femoral condyle fracture following an ACL revision reconstruction.

Lateral femoral condyle fractures following an ACL reconstruction are rare. To our knowledge, this is the first case report of a lateral femoral condyle fracture following a revision ACL reconstruction. The patient's fracture was intra-articular, had a significant amount of soft tissue damage, and was further complicated by a large defect involving the bone tunnel from the ACL revision reconstruction. The patient was treated with an open reduction and internal fixation and recovered well.

An in vitro analysis of an anatomical medial knee reconstruction.

BACKGROUND: An anatomical medial knee reconstruction has not been described in the literature. HYPOTHESIS: Knee stability and ligamentous load distribution would be restored to the native state with an anatomical medial knee reconstruction. STUDY DESIGN: Controlled laboratory study. METHODS: Ten nonpaired cadaveric knees were tested in the intact, superficial medial collateral ligament and posterior oblique ligament-sectioned, and anatomically reconstructed states. Each knee was tested at 0 degrees , 20 degrees , 30 degrees , 60 degrees , and 90 degrees of knee flexion with a 10-N.m valgus load, 5-N.m external and internal rotation torques, and 88-N anterior and posterior drawer loads. A 6 degrees of freedom electromagnetic motion tracking system measured angulation and displacement changes of the tibia with respect to the femur. Buckle transducers measured the loads on the intact and reconstructed proximal and distal divisions of the superficial medial collateral ligament and the posterior oblique ligament. RESULTS: A significant increase was found in valgus angulation and external rotation after sectioning the medial knee structures at all tested knee flexion angles. This was restored after an anatomical medial knee reconstruction. The authors also found a significant increase in internal rotation at 0 degrees , 20 degrees , 30 degrees , and 60 degrees of knee flexion after sectioning the medial knee structures, which was restored after the reconstruction. A significant increase in anterior translation was observed after sectioning the medial knee structures at 20 degrees , 30 degrees , 60 degrees , and 90 degrees of knee flexion. This increase in anterior translation was restored following the reconstruction at 20 degrees and 30 degrees of knee flexion, but was not restored at 60 degrees and 90 degrees . A small, but significant, increase in posterior translation was found after sectioning the medial knee structures at 0 degrees and 30 degrees of knee flexion, but this was not restored after the reconstruction. Overall, there were no clinically important differences in observed load on the ligaments when comparing the intact with the reconstructed states for valgus, external and internal rotation, and anterior and posterior drawer loads. Conclusion An anatomical medial knee reconstruction restores near-normal stability to a knee with a complete superficial medial collateral ligament and posterior oblique ligament injury, while avoiding overconstraint of the reconstructed ligament grafts. CLINICAL SIGNIFICANCE: This anatomical medial knee reconstruction technique provides native stability and ligament load distribution in patients with chronic or severe acute medial knee injuries.

Medial knee injury: Part 2, load sharing between the posterior oblique ligament and superficial medial collateral ligament.

BACKGROUND: There is limited information regarding directly measured load responses of the posterior oblique and superficial medial collateral ligaments in isolated and multiple medial knee ligament injury states. HYPOTHESES: Tensile load responses from both the superficial medial collateral ligament and the posterior oblique ligament would be measurable and reproducible, and the native load-sharing relationships between these ligaments would be altered after sectioning of medial knee structures. STUDY DESIGN: Descriptive laboratory study. METHODS: Twenty-four nonpaired, fresh-frozen adult cadaveric knees were distributed into 3 sequential sectioning sequences. Buckle transducers were applied to the posterior oblique ligament and the proximal and distal divisions of the superficial medial collateral ligament; 10 N.m valgus moments and 5 N.m internal and external rotation torques were applied at 0 degrees , 20 degrees , 30 degrees , 60 degrees , and 90 degrees of knee flexion. RESULTS: With an applied valgus and external rotation moment, there was a significant load increase on the posterior oblique ligament compared with the intact state after sectioning all other medial knee structures. With an applied external rotation torque, there was a significant load decrease on the proximal division of the superficial medial collateral ligament from the intact state after sectioning all other medial knee structures. With an applied external rotation torque, the distal division of the superficial medial collateral ligament experienced a significant load increase from the intact state after sectioning the posterior oblique ligament and the meniscofemoral division of the deep medial collateral ligament. CONCLUSION: This study found alterations in the native load-sharing relationships of the medial knee structures after injury. Sectioning both the primary and secondary restraints to valgus and internal/external rotation of the knee alters the intricate load-sharing relationships that exist between the medial knee structures. CLINICAL SIGNIFICANCE: In cases in which surgical repair or reconstruction is indicated, consideration should be placed on repairing or reconstructing all injured medial knee structures to restore the native load-sharing relationships among these medial knee structures.