The distance between the fibular collateral ligament tunnel and the common peroneal nerve allows a posterolateral corner reconstruction without neurolysis.

PURPOSE: The most popular knee posterolateral corner (PLC) reconstruction techniques describe that a common peroneal nerve (CPN) neurolysis must be done to safely address the posterolateral aspect of the knee. The purpose of this study was to measure the distance between the CPN and the fibular insertion of the FCL in different degrees of knee flexion in cadaveric specimens, to identify if tunnel drilling could be done anatomically and safely without a CPN neurolysis. METHODS: Ex vivo experimental analytical study. Ten fresh frozen human knees were dissected leaving FCL and CPN in situ. Shortest distance from the centre of the FCL distal tunnel and CPN was measured (antero-posterior and proximal-distal wire-nerve distances) at 90°, 60°, 30°, and 0° of knee flexion. Measurements between different flexion angles were compared and correlation between knee flexion angle and distance was identified. RESULTS: The mean distance between the FCL tunnel and the CPN at 90° were 21.15 ± 6.74 mm posteriorly (95% CI: 16.33-25.97) and 13.01 ± 3.55 mm distally (95% CI: 10.47-15.55). The minimum values were 9.8 mm posteriorly and 8.9 mm, respectively. These distances were smaller at 0° (p ≤ 0.017). At 90° of knee flexion, the mean distance from the fibular tip to the CPN distally was 23.46 ± 4.13 mm (20.51-26.41). CONCLUSION: Anatomic localization and orientation of fibular tunnels can be done safely while avoiding nerve neurolysis. Further studies should aim to in vivo measurements and results.

The AO classification system for tibial plateau fractures: An independent inter and intraobserver agreement study.

PURPOSE: Classifying tibial plateau fractures is paramount in determining treatment regimens and systemizing decision making. The original AO classification described by Müller in 1996 and the Schatzker classification of 1970 are the most cited classifications for tibial plateau fractures, demonstrating substantial to almost perfect agreement. The main problem with these classifications schemes is that they lack the detail required to convey the variety of fracture patterns encountered. In 2018, the AO foundation published a new classification system for proximal tibia fractures, highlighting a more complete and detailed number of categories and subcategories. We sought to independently determine inter and intraobserver agreement of the AO classification system, compared to the previous systems described by Müller and Schatzker. METHODS: One hundred seven consecutive tibial plateau fractures were screened, and a representative data set of 69 was created. Six independent evaluators (three knee surgeons, three senior orthopedic residents) classified the fractures using the original AO, the Schatzker and the new AO classifications. After six weeks, the 69 cases were randomized and reclassified by all evaluators. The Kappa coefficient (k) was calculated for inter- and intraobserver correlation and is expressed with 95% confidence intervals. RESULTS: interobserver agreement was moderate for all three classifications. k = 0.464 (0.383-0.560) for the original AO; k = 0.404 (0.337-0.489) for Schatzker; and k = 0.457 (0.371-0.545) for the base categories of the new AO classification. The inclusion of subcategories and letter modifiers to the new classification worsened agreement to k = 0.358 (0.302-0.423) and k = 0.174 (0.134-0.222), respectively. There were no significant differences between knee surgeons and residents for the new classification. Intra-observer correlation was also moderate for each of the scores: k = 0.630 (0.578-0.682) for the original AO; k = 0.623 (0.569-0.674) for Schatzker; and k = 0.621 (0.566-0.678) for the new AO base categories; without differences between knee surgeons or residents. CONCLUSIONS: This study demonstrated an adequate inter and intra-observer agreement for the new AO tibial plateau fractures classification system for its base categories, but not at the subcategory or letter modifier levels.

Tibial Cut Accuracy in Mechanically Aligned Total Knee Arthroplasty Using Extensor Hallucis Longus Tendon to Determine Extramedullary Tibial Guide Position.

This study aimed to determine the tibial cut (TC) accuracy using extensor hallucis longus (EHL) tendon as an anatomical landmark to position the total knee arthroplasty (TKA) extramedullary tibial guide (EMTG), and its impact on the TKA mechanical alignment (MA). We retrospectively studied 96 TKA, performed by a single surgeon, using a femoral tailored intramedullary guide technique. Seventeen were prior to the use of the EHL and 79 used the EHL tendon to position the EMTG. We analyzed preoperative and postoperative standing total lower extremity radiographs to determine the tibial component angle (TCA) and the correction in MA, comparing pre-EHL use and post-EHL technique incorporation. Mean TCA was 88.89 degrees and postoperative MA was neutral in 81% of patients. Pre- and postoperative MAs were not correlated. As a conclusion of this study, using the EHL provides a safe and easy way to determine the position of EMTG.

Prevalence of lumbar high-intensity zone: assessment using a screening tool independent of spinal symptoms.

High-intensity zone is an area of high-intensity signal within the posterior annulus fibrosus observed in magnetic resonance imaging; initially described in painful discs, recent studies have described similar prevalence in symptomatic and asymptomatic subjects. Since its' prevalence in the general population has not been established, we used a screening tool independent of spinal symptoms to determine high-intensity zone prevalence. We studied 217 patients evaluated with abdominal-pelvic magnetic resonance imaging; we looked for high-intensity zone, disc degeneration, spondylolysis, spondylolisthesis, Modic changes and scoliosis. We determined if these variables, age and sex affected the presence of high-intensity zone; through a logistic regression analysis we evaluated their independent effect. Patients' mean age was 56.3±17.4 years; 66.8% were females. Prevalence of high-intensity zone (11.06%) was larger in males (18.06%) than females (7.59%), p = 0.02. Patients with and without high-intensity zone did not differ in age or presence of scoliosis. High-intensity zone was more frequent in degenerated discs, but not in levels with spondylolisis, spondylolisthesis or Modic changes. Male sex (OR = 2.3, 1.04-5.38) and disc degeneration (OR = 6.76, 1.77-25.81) independently influenced the presence of high-intensity zone. The prevalence of high-intensity zone in this sample of the general population, including 217 subjects, was 11.06%. Similarly, a recent meta-analysis mentioned a 9.5% prevalence in asymptomatic subjects; on the other hand it stressed a 10.4% prevalence in symptomatic subjects. All these data do not plead for a strict correlation between high-intensity zone and low back pain complaints.