Standardized analysis of syndesmosis stability in ankle trauma with an innovative syndesmosis-test-tool: a biomechanical study.

When treating ankle fractures, the question of syndesmosis complex involvement often arises. So far, there is no standardized method to reliably detect syndesmosis injuries in the surgical treatment of ankle fractures. For this reason, an intraoperative syndesmosis-test-tool (STT) was developed and compared to the recommended and established hook-test (HT). Tests were performed on cadaveric lower legs (n = 20) and the diastasis was visualized by 3D camera. Tests were performed at 50, 80, and 100 N in native conditions and four instability levels. Instability was induced from anterior to posterior and the reverse on the opposite side. The impact on diastasis regarding the direction, the force level, the instability level, and the device used was checked using a general linear model for repeated measurement. The direction of the induced instability showed no influence on the diastasis during the stability tests. The diastasis measured with the STT increased from 0.5 to 3.0 mm depending on the instability, while the range was lower with the HT (1.1 to 2.3 mm). The results showed that the differentiation between the instability levels was statistically significantly better for the developed STT. The last level of maximum instability was significantly better differentiable with the STT compared to the HT. An average visualizable diastasis of more than 2 mm could only be achieved at maximum instability. In conclusion, the newly developed STT was superior to the commonly used HT to detect instability.

Minimally invasive bilateral fixed angle locking fixation of the dorsal pelvic ring: clinical proof of concept and preliminary treatment results.

PURPOSE: Dorsal pelvic ring fractures may result from high energy trauma in younger patients or from osteoporosis as fragility fractures in elderly patients. To date, no strong consensus exists on the best surgical technique to treat posterior pelvic ring injuries. The aim of this study was to evaluate the surgical performance of a new implant for angle-stable fixation of the posterior pelvic ring and patient outcome. METHODS: In a prospective pilot study, 27 patients (age: 39-87 years) with posterior pelvic ring fractures classified according to the AO classification (n = 5) or to the fragility fractures of the pelvis (FFP) classification (n = 22) were treated using the new implant. During a follow-up period of 1 year, surgical parameters of the implantation technique, complication rate, morbidity, mortality, preservation of patient mobility, and social independence were evaluated. RESULTS: No implant misplacement or failure was observed. Two patients developed symptomatic spinal canal stenosis at L4/L5 following mobilization. MRI diagnosis proved the implant was not responsible for the symptoms. In one case, an additional plate stabilization of a pubic ramus fracture was necessary 6 months later. There was no inpatient mortality. One patient died due to her underlying oncological disease within the first 3 months. The main outcome parameters were pain, mobility, preservation of independent living and employment. CONCLUSION: Operative instrumentation of dorsal pelvic ring fractures should be stable enough to allow for immediate weight bearing. The new locking nail implant offers percutaneous reduction and fixation options and may decrease the generally observed rate of complications. TRAIL REGISTRATION: German Clinical Trials Register ID: DRKS00023797, date of registration: 07.12.2020.

Direct and indirect comparisons in network meta-analysis of SuperPATH, direct anterior and posterior approaches in total hip arthroplasty.

SuperPATH is a novel approach to the hip joint that needs to be compared to other known surgical approaches. To conduct a network meta-analysis (NMA) of randomized controlled trials (RCTs) comparing short-term outcomes of SuperPATH, direct anterior (DAA), and posterior/ posterolateral approaches (PA) in total hip joint arthroplasty (THA). We performed a systematic review on PubMed, CNKI, Embase, The Cochrane Library, Clinical trials, and Google Scholar up to November 30th, 2021. We assessed treatment effects between SuperPATH, DAA, and PA by performing a frequentist NMA, including a total of 20 RCTs involving 1501 patients. SuperPATH showed a longer operation time (MD = 16.99, 95% CI 4.92 to 29.07), a shorter incision length (MD = -4.71, 95% CI -6.21 to -3.22), a lower intraoperative blood loss (MD = -81.75, 95% CI -114.78 to -48.72), a higher HHS 3, 6 and 12 months postoperatively (MD = 2.59, 95% CI 0.59-4.6; MD = 2.14, 95% CI 0.5-3.77; MD = 0.6, 95% CI 0.03-1.17, respectively) than PA. DAA showed a higher intraoperative blood loss than PA and SuperPATH (MD = 91.87, 95% CI 27.99-155.74; MD = 173.62, 95% CI 101.71-245.53, respectively). No other relevant differences were found. In conclusion, the overall findings suggested that the short-term outcomes of THA through SuperPATH were statistically superior to PA. DAA and PA as well as SuperPATH and DAA showed indifferent results.

Direct anterior approach vs. SuperPATH vs. conventional approaches in total hip replacement: A network meta-analysis of randomized controlled trials.

BACKGROUND: Two minimally invasive approaches showed some advantages in outcomes compared to conventional approaches (CAs) - the direct anterior approach (DAA) and the supercapsular percutaneously assisted approach in THA (SuperPATH). To the best of our knowledge, these three approaches have never been ranked in a network meta-analysis (NMA) before. Therefore, we conducted a systematic review and NMA of randomized controlled trials comparing short-term outcomes of DAA, SuperPATH and CAs in total hip joint arthroplasty (THA), using CAs as common comparator. METHODS: A systematic literature search up to February 2021 was performed to identify randomized controlled trials (RCTs) comparing DAA with CAs and SuperPATH with CAs in THA. We measured surgical, functional and radiological outcomes. A NMA, using frequentist methods was performed to assess treatment effects between DAA, SuperPATH and CAs. Information was borrowed from the above-mentioned RCTs, using the CA group as a common comparator. RESULTS: A total of 24 RCTs involving 2,074 patients met the inclusion criteria, six trials with a level I evidence, 18 trials with level II evidence. SuperPATH reduced operation time (fixed effects model: MD=8.1, 95% CI: 5.7 to 10.4), incision length (fixed effects model: MD=2.7, 95%CI: 2.5 to 2.9; random effects model: MD=4.1, 95%CI: 0.6 to 7.6), intraoperative blood loss (fixed effects model: MD=157, 95%CI: 139.2 to 174.2; random effects model: MD=129, 95%CI: 11.5 to 245.7) and early pain intensity (VAS 1 day postoperatively with a fixed effects model: MD=0.8, 95%CI: 0.4 to 1.2) compared to DAA. The two approaches did not differ in functional outcome and in acetabular cup inclination positioning. CONCLUSIONS: Our overall findings suggest that short-term outcomes of THA through SuperPATH were superior to DAA and CAs and that short-term outcomes of THA through DAA were superior to CAs. LEVEL OF EVIDENCE: II; systematic review with level I studies and level II studies.

Comparison of short-term outcomes between direct anterior approach (DAA) and SuperPATH in total hip replacement: a systematic review and network meta-analysis of randomized controlled trials.

BACKGROUND: Two minimally invasive approaches showed some advantages in outcomes compared to conventional approaches (CAs)-the direct anterior approach (DAA) and the supercapsular percutaneously assisted approach in THA (SuperPATH). To the best of our knowledge, DAA and SuperPATH have never been compared, neither in clinical studies, nor in a meta-analysis. To conduct a systematic review and network meta-analysis of randomized controlled trials comparing short-term outcomes of DAA and SuperPATH in total hip joint arthroplasty (THA). METHODS: A systematic literature search up to May 2020 was performed to identify randomized controlled trials (RCTs) comparing SuperPATH with CAs and DAA with CAs in THA. We measured surgical, functional, and radiological outcomes. A network meta-analysis, using frequentist methods, was performed to assess treatment effects between DAA and SuperPATH. Information was borrowed from the above-mentioned RCTs, using the CA group as a common comparator. RESULTS: A total of 16 RCTs involving 1392 patients met the inclusion criteria, three trials with a level I evidence, 13 trials with a level II evidence. The overall network meta-analysis showed that SuperPATH reduced operation time (fixed effect model: MD = 12.8, 95% CI 9.9 to 15.7), incision length (fixed effect model: MD = 4.3, 95% CI 4.0 to 4.5; random effect model: MD = 4.3, 95% CI 0.2 to 8.4), intraoperative blood loss (fixed effect model: MD = 58.6, 95% CI 40.4 to 76.8), and early pain intensity (VAS 1 day postoperatively with a fixed effect model: MD = 0.8, 95% CI 0.4 to 1.2). The two approaches did not differ in acetabular cup positioning angles and in functional outcome. CONCLUSIONS: Our overall findings suggested that the short-term outcomes of THA through SuperPATH were superior to DAA. SuperPATH showed better results in decreasing operation time, incision length, intraoperative blood loss, and early pain intensity. DAA and SuperPATH were equal in functional outcome and acetabular cup positioning.

[Comparison between navigated and conventional percutaneous screw fixation of non-displaced scaphoid fractures]. / Vergleich der navigierten und konventionellen perkutanen Verschraubung undislozierter Kahnbeinfrakturen.

BACKGROUND: Incorrect screw placement and penetration in screw fixation of scaphoid fractures are found in 5 to 30 %. Therefore, optimizing of screw placement is desirable, especially because an exact central position of the screw in the proximal fragment leads to a significant higher stability as a more peripheral position. PATIENTS UND METHODS: 36 patients with an acute non-displaced scaphoid fracture were included in this randomized prospective study. 18 patients underwent navigated, the other 18 conventional percutaneous screw fixation of an acute non-displaced scaphoid fracture through a dorsal approach. Operation time and x-ray dose were measured. In both groups the position of the screw in the scaphoid was calculated on CT scans and compared with each other. Clinically, 17 patients with navigated and 11 with conventional percutaneous screw fixation with an average age of 52 resp. 43.2 years were available for follow-up examination including Krimmer- and DASH-score. RESULTS: All scaphoids healed within an adequate time. Two cases of navigated screw fixation have been converted to conventional percutaneous screw fixation. The average operation time in the navigated group was 83.2 minutes, in the conventional group 42.1 minutes. X-ray dose measured 106,5 ± 19,9cGy/cm2 in the navigated group and 45,6 ± 8,0cGy/cm2 in the conventional group. Screw penetration using an intraosseous compression screw (HSC) was observed in 5 conventionally fixed scaphoids, 4 distally (2,27 ± 1,47 mm), 1 proximally. In the navigated group there were 11 screw penetrations, 4 proximally (2,01 ± 0,81 mm) and distally (1,21 ± 0,64 mm), 3 distally (1,18 ± 0,44 mm), and 4 proximally (1,61 ± 0,57 mm). Axial screw position was more accurate in the conventional group. The 17 navigated patients averaged a Krimmer-Score of 83.6 and a DASH-score of 5,6 points at follow-up. The 11 conventional treated patients averaged a Krimmer-Score of 95 and a DASH-score of 8.0 points at follow-up. CONCLUSION: In this study navigated screw fixation of acute non-displaced scaphoid fractures was not superior to conventional percutaneous screw fixation, neither for screw position, screw penetration nor with respect to the clinical outcome.

Modified therapy concepts for fragility fractures of the pelvis after additional MRI.

BACKGROUND: Fractures of the pelvic ring in elderly patients have increased in frequency over time. These injuries are associated with a high morbidity and have a socio-economic impact. The diagnostic procedures and their influence of therapy decisions are still controversial. METHODS: In a retrospective study, we investigate the value of additional MRI examination on therapy decision of fragility fractures of the pelvis. The evaluation of all patients with pelvic fractures without adequate trauma and with performed CT and MRI was conducted at three large German hospitals. The imaging procedure took place within a maximum interval of 4 weeks. After evaluation of the imaging, the resulting therapeutic consequences either based on CT alone or on CT and MRI were reviewed by experienced pelvic surgeons. RESULTS: Of 754 patients with pelvic injuries, 67 (age 80 +/- 9.7 years, f: m 54:13) could be included. The detection of vertical fractures in CT (n = 40 unilateral, n = 11 bilateral) could be increased by the additional MRI (n = 44 unilateral, n = 23 bilateral). A horizontal fracture component was identified in CT in 9.0% (n = 6) vs. MRI in 25.4% (n = 17) of the cases. An anterior pelvic ring injury was detected in 71.6% (n = 44; 4x bilateral) in CT, in 80.6% in MRI (n = 50, 4 bilateral). Additive MRI imaging increased the decision rate for surgical therapy from 20.9% (n = 14) to 31.3% (n = 21). CONCLUSIONS: The results of this study further support the value of bone marrow edema detection by MRI diagnostics (or dual source CT which showed promising initial results) for the detection of pelvic ring fractures. For the first time, the study identifies an additional therapeutic consequence by an increased rate of surgical procedures.

Effect of different multiplanar reformation algorithms on image quality of intraoperative three-dimensional fluoroscopy.

Different multiplanar reformation (MPR-512 and -256) algorithms of intraoperative acquired 3-D-fluoroscopy data exist without recommendations for use in the literature. To compare algorithms, 3-D-fluoroscopic data sets of 46 radius fractures were blinded and processed using MPR-256 and -512 (Ziehm, Vision-Vario 3D). Each reformatted data set was analysed to evaluate image quality, fracture reduction quality and screw misplacements. Overall image quality was higher rated in the MPR-512 compared with the MPR-256 (3.2 vs. 2.2 points, scale 1-5 points), accompanied by a reduced number of scans that could not be analysed (10 vs. 19%). Interobserver evaluation of fracture reduction quality was fair to moderate (independent of the algorithm). In contrast, for screw misplacements MPR-depended ratings were found (MPR-256: fair to moderate; MPR-512: moderate to substantial). Optimization of post-processing algorithms, rather than modifications of image acquisition, may increase the image quality for assessing implant positioning, but limitations in evaluating fracture reduction quality still exist.

Recommendations for iliosacral screw placement in dysmorphic sacrum based on modified in-out-in corridors.

(1) Can iliosacral osseous corridor diameters in sacral dysmorphism be enlarged by in-out-in screw placement at the posterior iliosacral recessus? (2) Are lumbosacral transitional vertebra (LSTV) the anatomical cause for sacral dysmorphism? (3) Are there sex-specific differences in sacral dysmorphism? 594 multislice CT scans were screened for sacral dysmorphism and 55 data-sets selected. Each pelvis was segmented manually and cylindrical iliosacral corridors (on the level of S1 and S2 vertebra) were semi-automatically determined. Corridor trajectories, -diameters and -lengths were measured. LSTV (Castellvi-type IIIb and IV) were found in 3 of 55 pelves and these lumbosacral variations are therefore not the anatomical basis for sacral dysmorphism. The prevalence of transsacral osseous corridors with diameters of <7.5 mm in axial CT images correlates with qualitative and quantitative criteria of sacral dysmorphism. Enlarging the osseous corridor diameters by penetration of the posterior iliosacral recessus increase the safe corridor diameters (females versus males) by 26% versus 15% at the level of S1- and 50% versus 48% at the level of S2-vertebra. Sex-specific differences for both corridors (osseous and in-out-in) were only found for the osseous corridor diameters at the level of S1 vertebra, being smaller in females (females versus males: 13.3 ± 3.6 mm versus 15.5 ± 3.8 mm, p = 0.04). Dysmorphic sacra can be reliably detected on standard axial CT slice images. Modified in-out-in corridors on the level of S1-vertebra allow screw placement in all patients, but is still demanding compared to non-dysmorphic sacra, due to the oblique corridor axis. Recommendations for intraoperative orientation for oblique screw placement are defined. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Predictors for secondary hip osteoarthritis after acetabular fractures-a pelvic registry study.

PURPOSE: Secondary hip osteoarthritis after acetabular fractures requiring total arthroplasty (THA) poses a huge burden on the affected patients as well as health systems. The present study aimed to assess risk factors associated with THA after acetabular fractures based on the data from the German Pelvic Trauma Registry. METHODS: Retrospective analysis of 678 acetabular fracture cases without concomitant pelvic ring fracture treated and followed-up between January 2004 and May 2015 at six large trauma centres. Multivariate Cox regression analysis was performed assessing the association of patient/treatment characteristics with THA likelihood at an average follow-up of 2.7 years (range 0.4-9.5 years; SD 1.8 years). RESULTS: Overall, the rate of secondary osteoarthritis was 19.8%. The likelihood for THA increased with 6% per age year (95% CI 1.04-1.09) and with 21% per millimetre subluxation (95%CI 1.09-1.33). This likelihood was 3.54 (95% CI 1.77-7.08) and 3.68 times (95% CI 1.87-7.47) higher if the posterior wall was involved and a contusion and/or impaction of the femoral head was present. Other covariates (sex, ISS, trauma type, AO/OTA and Letournel classification, initial displacement, surgical approach, intra-articular fragments, contusion and/or impaction to the acetabulum, reduction, intervention type, duration of surgery, soft tissue damage, residual fracture step/gap, and prevention of heterotopic ossifications) were not significantly associated (p > 0.15). CONCLUSIONS: Twenty percent of patients with acetabular fractures require THA. The associated risk factors are patient age, femoral head lesion/subluxation, and involvement of the posterior wall. The identified risk factors support previous research and should be minded when treatment of acetabular fractures is planned.

Pain sensation in human osteoarthritic knee joints is strongly enhanced by diabetes mellitus.

The major burden of knee joint osteoarthritis (OA) is pain. Since in elder patients diabetes mellitus is an important comorbidity of OA, we explored whether the presence of diabetes mellitus has a significant influence on pain intensity at the end stage of knee OA, and we aimed to identify factors possibly related to changes of pain intensity in diabetic patients. In 23 diabetic and 47 nondiabetic patients with OA undergoing total knee arthroplasty, we assessed the pain intensity before the operation using the "Knee Injury and Osteoarthritis Outcome Score". Furthermore, synovial tissue, synovial fluid (SF), cartilage, and blood were obtained. We determined the synovitis score, the concentrations of prostaglandin E2 and interleukin-6 (IL-6) in the SF and serum, and of C-reactive protein and HbA1c and other metabolic parameters in the serum. We performed multivariate regression analyses to study the association of pain with several parameters. Diabetic patients had on average a higher Knee Injury and Osteoarthritis Outcome Score pain score than nondiabetic patients (P < 0.001). Knee joints from diabetic patients exhibited on average higher synovitis scores (P = 0.024) and higher concentrations of IL-6 in the SF (P = 0.003) than knee joints from nondiabetic patients. Multivariate regression analysis showed that patients with higher synovitis scores had more intense pain independent of all investigated confounders, and that the positive association between pain intensities and IL-6 levels was dependent on diabetes mellitus and/or synovitis. These data suggest that diabetes mellitus significantly increases pain intensity of knee OA, and that in diabetic patients higher pain intensities were determined by stronger synovitis.

The Anterior Intrapelvic Approach for Acetabular Fractures Using Approach-Specific Instruments and an Anatomical-Preshaped 3-Dimensional Suprapectineal Plate.

OBJECTIVES: Anatomical acetabular plates the anterior intrapelvic approach (AIP) were recently introduced to fix acetabular fractures through the intrapelvic approach. Therefore, we asked the following: (1) Does the preshaped 3-dimensional suprapectineal plate interfere with or even impair the fracture reduction quality? (2) How often does the AIP approach need to be extended by the first (lateral) window of the ilioinguinal approach? DESIGN: Observational case series. SETTING: Two Level 1 trauma centers. PATIENTS/PARTICIPANTS: Patients with unstable acetabular fractures in 2014. INTERVENTION: Fracture fixation with anatomical-preshaped, 3-dimensional suprapectineal plates through the AIP approach ± the first window of the ilioinguinal approach. OUTCOME MEASUREMENTS: Fracture reduction results were measured in computed tomography scans and graded according to the Matta quality of reduction. Intraoperative parameters and perioperative complications were recorded. Radiological results (according to Matta) and functional outcome (modified Merle d'Aubigné score) were evaluated at 1-year follow-up. RESULTS: Thirty patients (9 women + 21 men; mean age ± SE: 64 ± 8 years) were included. The intrapelvic approach was solely used in 19 cases, and in 11 cases, an additional extension with the first window of the ilioinguinal approach (preferential for 2-column fractures) was performed. The mean operating time was 202 ± 59 minutes; the fluoroscopic time was 66 ± 48 seconds. Fracture gaps and steps in preoperative versus postoperative computed tomography scans were 12.4 ± 9.8 versus 2.0 ± 1.5 and 6.0 ± 5.5 versus 1.3 ± 1.7 mm, respectively. At 13.4 ± 2.9 months follow-up, the Matta grading was excellent in 50%, good in 25%, fair in 11%, and poor in 14% of cases. The modified Merle d'Aubigné score was excellent in 17%, good in 37%, fair in 33%, and poor in 13% of cases. CONCLUSION: The AIP approach using approach-specific instruments and an anatomical-preshaped, 3-dimensional suprapectineal plate became the standard procedure in our departments. Radiological and functional early results justify joint preserving surgery in most cases. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Transsacral Osseous Corridor Anatomy Is More Amenable To Screw Insertion In Males: A Biomorphometric Analysis of 280 Pelves.

BACKGROUND: Percutaneous iliosacral screw placement is the standard procedure for fixation of posterior pelvic ring lesions, although a transsacral screw path is being used more frequently in recent years owing to increased fracture-fixation strength and better ability to fix central and bilateral sacral fractures. However, biomorphometric data for the osseous corridors are limited. Because placement of these screws in a safe and effective manner is crucial to using transsacral screws, we sought to address precise sacral anatomy in more detail to look for anatomic variation in the general population. QUESTIONS/PURPOSES: We asked: (1) What proportion of healthy pelvis specimens have no transsacral corridor at the level of the S1 vertebra owing to sacral dysmorphism? (2) If there is no safe diameter for screw placement in the transsacral S1 corridor, is an increased and thus safe diameter of the transsacral S2 corridor expected? (3) Are there sex-specific differences in sacral anatomy and are these correlated with known anthropometric parameters? METHODS: CT scans of pelves of 280 healthy patients acquired exclusively for medical indications such as polytrauma (20%), CT angiography (70%), and other reasons (10%), were segmented manually. Using an advanced CT-based image analysis system, the mean shape of all segmented pelves was generated and functioned as a template. On this template, the cylindric transsacral osseous corridor at the level of the S1 and S2 vertebrae was determined manually. Each pelvis then was registered to the template using a free-form registration algorithm to measure the maximum screw corridor diameters on each specimen semiautomatically. RESULTS: Thirty of 280 pelves (11%) had no transsacral S1 corridor owing to sacral dysmorphism. The average of maximum cylindrical diameters of the S1 corridor for the remaining 250 pelves was 12.8 mm (95% CI, 12.1-13.5 mm). A transverse corridor for S2 was found in 279 of 280 pelves, with an average of maximum cylindrical diameter of 11.6 mm (95% CI, 11.3-11.9 mm). Decreasing transsacral S1 corridor diameters are correlated with increasing transsacral S2 corridor diameters (R value for females, -0.260, p < 0.01; for males, -0.311, p < 0.001). Female specimens were more likely to have sacral dysmorphism (defined as a pelvis without a transsacral osseous corridor at the level of the S1 vertebra) than were male specimens (females, 16%; males, 7%; p < 0.003). Furthermore female pelves had smaller-corridor diameters than did male pelves (females versus males for S1: 11.7 mm [95% CI, 10.6-12.8 mm] versus 13.5 mm [95% CI, 12.6-14.4 mm], p < 0.01; and for S2: 10.6 mm [95% CI, 10.1-11.1 mm] versus 12.2 mm [95% CI, 11.8-12.6 mm ], p < 0.0001). CONCLUSIONS: Narrow corridors and highly individual, sex-dependent variance of morphologic features of the sacrum make transsacral implant placement technically demanding. Individual preoperative axial-slice CT scan analyses and orthogonal coronal and sagittal reformations are recommended to determine the prevalence of sufficient-sized osseous corridors on both levels for safe screw placements, especially in female patients, owing to their smaller corridor diameters and higher rate of sacral dysmorphism.

Tangential View and Intraoperative Three-Dimensional Fluoroscopy for the Detection of Screw-Misplacements in Volar Plating of Distal Radius Fractures.

BACKGROUND: Volar locking plate fixation has become the gold standard in the treatment of unstable distal radius fractures. Juxta-articular screws should be placed as close as possible to the subchondral zone, in an optimized length to buttress the articular surface and address the contralateral cortical bone. On the other hand, intra-articular screw misplacements will promote osteoarthritis, while the penetration of the contralateral bone surface may result in tendon irritations and ruptures. The intraoperative control of fracture reduction and implant positioning is limited in the common postero-anterior and true lateral two-dimensional (2D)-fluoroscopic views. Therefore, additional 2D-fluoroscopic views in different projections and intraoperative three-dimensional (3D) fluoroscopy were recently reported. Nevertheless, their utility has issued controversies. OBJECTIVES: The following questions should be answered in this study; 1) Are the additional tangential view and the intraoperative 3D fluoroscopy useful in the clinical routine to detect persistent fracture dislocations and screw misplacements, to prevent revision surgery? 2) Which is the most dangerous plate hole for screw misplacement? PATIENTS AND METHODS: A total of 48 patients (36 females and 13 males) with 49 unstable distal radius fractures (22 x 23 A; 2 x 23 B, and 25 x 23 C) were treated with a 2.4 mm variable angle LCP Two-Column volar distal radius plate (Synthes GmbH, Oberdorf, Switzerland) during a 10-month period. After final fixation, according to the manufactures' technique guide and control of implant placement in the two common perpendicular 2D-fluoroscopic images (postero-anterior and true lateral), an additional tangential view and intraoperative 3D fluoroscopic scan were performed to control the anatomic fracture reduction and screw placements. Intraoperative revision rates due to screw misplacements (intra-articular or overlength) were evaluated. Additionally, the number of surgeons, time and radiation-exposure, for each step of the operating procedure, were recorded. RESULTS: In the standard 2D-fluoroscopic views (postero-anterior and true lateral projection), 22 screw misplacements of 232 inserted screws were not detected. Based on the additional tangential view, 12 screws were exchanged, followed by further 10 screws after performing the 3D fluoroscopic scan. The most lateral screw position had the highest risk for screw misplacement (accounting for 45.5% of all exchanged screws). The mean number of images for the tangential view was 3 ± 2.5 images. The mean surgical time was extended by 10.02 ± 3.82 minutes for the 3D fluoroscopic scan. An additional radiation exposure of 4.4 ± 4.5seconds, with a dose area product of 39.2 ± 14.5 cGy/cm(2) were necessary for the tangential view and 54.4 ± 20.9 seconds with a dose area product of 2.1 ± 2.2 cGy/cm(2), for the 3D fluoroscopic scan. CONCLUSIONS: We recommend the additional 2D-fluoroscopic tangential view for detection of screw misplacements caused by overlength, with penetration on the dorsal cortical surface of the distal radius, predominantly observed for the most lateral screw position. The use of intraoperative 3D fluoroscopy did not become accepted in our clinical routine, due to the technical demanding and time consuming procedure, with a limited image quality so far.

Biomorphometric analysis of ilio-sacro-iliacal corridors for an intra-osseous implant to fix posterior pelvic ring fractures.

It is hypothesized that ilio-sacro-iliacal corridors for a new envisioned pelvic ring implant (trans-sacral nail with two iliacal bolts = ISI-nail: ilio-sacro-iliacal nail) exists on the level of S1- or S2-vertebra in each patient. The corridors of 84 healthy human pelves (42x ♂; 42x ♀, 18-85 years) were measured in high resolution CT scans using the Merlin Diagnostic Workcenter Software. Trans-sacral corridors (≥ 9 mm diameter) on the level of S1 and S2 were found in 62% and 54% of pelves with a mean length [mm ± SD] of 164 ± 12.9 and 142 ± 10.2. Corresponding iliac corridors were present in all specimens in caudally tilted axial planes of 37.8 ± 0.67° and 53.7 ± 0.94° in relation to the operating table plane and divergent angulations of 69.0 ± 0.49° and 70.1 ± 0.32° in relation to the sagittal midline plane. Sacral dysmorphism, with compensatory larger S2 corridors were prevalent in 24% of pelves; ilio-sacro-iliacal osseous corridors for the envisioned implant were found in 88% of pelves on the level of S1 or S2. In the remaining 12% with too narrow corridors for any trans-sacral implant (screws, bars, ISI nail) alternative fixation methods have to be considered. Expected advantages of the envisioned ISI nail compared to available fixation devices are discussed.

Sex-specific differences of the infraacetabular corridor: a biomorphometric CT-based analysis on a database of 523 pelves.

BACKGROUND: An infraacetabular screw path facilitates the closure of a periacetabular fixation frame to increase the plate fixation strength in acetabular fractures up to 50%. Knowledge of the variance in corridor sizes and axes has substantial surgical relevance for safe screw placement. QUESTIONS/PURPOSES: (1) What proportion of healthy pelvis specimens have an infraacetabular corridor that is 5 mm or larger in diameter? (2) Does a universal corridor axis and specific screw entry point exist? (3) Are there sex-specific differences in the infraacetabular corridor size or axis and are these correlated with anthropometric parameters like age, body weight and height, or the acetabular diameter? METHODS: A template pelvis with a mean shape from 523 segmented pelvis specimens was generated using a CT-based advanced image analyzing system. Each individual pelvis was registered to the template using a free-form registration algorithm. Feasible surface regions for the entry and exit points of the infraacetabular corridor were marked on the template and automatically mapped to the individual samples to perform a measurement of the maximum sizes and axes of the infraacetabular corridor on each specimen. A minimum corridor diameter of at least 5 mm was defined as a cutoff for placing a 3.5-mm cortical screw in clinical settings. RESULTS: In 484 of 523 pelves (93%), an infraacetabular corridor with a diameter of at least 5 mm was found. Using the mean axis angulations (54.8° [95% confidence interval {CI}, 0.6] from anterocranial to posterocaudal in relation to the anterior pelvic plane and 1.5° [95% CI, 0.4] from anteromedial to posterolateral in relation to the sagittal midline plane), a sufficient osseous corridor was present in 64% of pelves. Allowing adjustment of the three-dimensional axis by another 5° included an additional 25% of pelves. All corridor parameters were different between females and males (corridor diameter, 6.9 [95% CI, 0.2] versus 7.7 [95% CI, 0.2] mm; p<0.001; corridor length, 96.2 [95% CI, 0.7] versus 106.4 [95% CI, 0.6] mm; p<0.001; anterior pelvic plane angle, 54.0° [95% CI, 0.9] versus 55.3° [95% CI, 0.8]; p<0.01; sagittal midline plane angle, 4.3° [95% CI, 0.6] versus -0.3° [95% CI, 0.5]; p<0.001). CONCLUSION: This study provided reference values for placement of a 3.5-mm cortical screw in the infraacetabular osseous corridor in 90% of female and 94% of male pelves. Based on the sex-related differences in corridor axes, the mean screw trajectory is approximately parallel to the sagittal midline plane in males but has to be tilted from medial to lateral in females. Considering the narrow corridor diameters, we suggest an individual preoperative CT scan analysis for fine adjustments in each patient.

Is there a correlation between biophotonical, biochemical, histological, and visual changes in the cartilage of osteoarthritic knee-joints?

The aim of this study was to detect characteristic structural changes in the cartilage composition of osteoarthritis (OA), hereby improving the arthroscopic identification of cartilage pathology by the use of a non-destructive technique - NIRS (Near-Infrared Spectroscopy). 682 cartilage samples out of 25 knees with OA were classified visually, using the ICRS system, biophotonically, histologically (n = 66), using the Score of Mankin and the Score of Otte, and biochemically (n = 616), determining the content of glycosaminoglycan (GAG) and hydroxyproline (HP). Significant correlations were found between biophotonical, histological, biochemical and visual characteristics of cartilage lesions. NIRS values corresponded to the content of GAG, HP and to the Score of Mankin and Otte. The data show that changes in the composition and structure of articular cartilage influence the optical properties and can be measured objectively by NIRS. The ease of use during arthroscopy, the quick response and the non-destructive nature of NIRS make it a promising addition to the assessment of disease intervention in OA.

Percutaneous navigated screw fixation of glenoid fractures.

BACKGROUND: Open or percutaneous arthroscopic-based procedures are reported to fix unstable or displaced intra-articular glenoid fractures. Approach related morbidity has to be considered for open procedures, and arthroscopic-based procedures are demanding. Therefore an alternative percutaneous navigated approach is described. TECHNICAL PROCEDURE: In an experimental setting an operative workflow was simulated to evaluate the best position of the patient on the operation table, the operating room set up and the fixation technique for the dynamic reference base of the navigation system. Based on two clinical cases, screw fixation of glenoid fractures via a posterior percutaneous approach is described, using a 2D-fluoroscopic based navigation system. Compared to the common approaches, the advantages and disadvantages of this procedure are discussed. CONCLUSION: The described technique of percutaneous navigated screw fixation of glenoid fractures is an alternative minimal invasive procedure. A reduction of approach related morbidity and more rapid return to function could be expected. The intraoperative results and postoperative functional outcome of both cases are promising.