Cartilage decisively shapes the glenoid concavity and contributes significantly to shoulder stability.

PURPOSE: Glenohumeral joint injuries frequently result in shoulder instability. However, the biomechanical effect of cartilage loss on shoulder stability remains unknown. The aim of the current study was to investigate biomechanically the effect of two severity stages of cartilage loss in different dislocation directions on shoulder stability. METHODS: Joint dislocation was provoked in 11 human cadaveric glenoids for 7 different directions between 3 o'clock (anterior) and 9 o'clock (posterior). Shoulder stability ratio (SSR) and concavity gradient were assessed in three states: intact, 3 mm and 6 mm simulated cartilage loss. The influence of cartilage loss on SSR and concavity gradient was statistically evaluated. RESULTS: Both SSR and concavity gradient decreased significantly between intact state and 6 mm cartilage loss in every dislocation direction (p ≤ 0.038), except concavity gradient in 4 o'clock direction. Thereby, anterior-inferior dislocation directions were associated with the highest decrease in both SSR and concavity gradient of up to 59.0% and 49.4%, respectively, being significantly bigger for SSR compared with all other dislocation directions (p ≤ 0.040). Correlations between concavity gradient and SSR for pooled dislocation directions were significant in each separate specimen's state (p < 0.001). CONCLUSION: From a biomechanical perspective, articular cartilage of the glenoid contributes significantly to the concavity gradient, correlating strongly with the associated loss in glenohumeral joint stability. The biggest effect of cartilage loss is observed in the most frequently occurring anterior-inferior dislocation directions, suggesting that surgical interventions to restore cartilage's surface and concavity should be considered for recurrent shoulder dislocations in presence of cartilage loss.

[Seasonal distribution of clinical case codes (DOC study)]. / Saisonale Verteilung klinischer Kennzahlen (DOC-Study).

OBJECTIVES: The German diagnosis-related groups remuneration system (G-DRG) was implemented in 2004 and patient-related diagnoses and procedures lead to allocation to specific DRGs. This system includes several codes, such as case mix (CM), case mix index (CMI) and number of cases. Seasonal distribution of these codes as well as distribution of diagnoses and DRGs may lead to logistical consequences for clinical management. METHODS: From 2004 to 2013 all the main diagnoses and DRGs for inpatients were recorded. Monthly and seasonal distributions were analyzed using ANOVA. RESULTS: The average monthly number of cases was 265 ± 25 cases, the average CM was 388.50 ± 51.75 and the average CMI was 1.46 ± 0.15 with no significant seasonal differences (p > 0.1). Concussion was the most frequently occurring main diagnosis (3739 cases) followed by fractures of the humeral head (699). Significant distribution differences could be shown for humeral head fractures in monthly (p = 0.018) and seasonal comparisons (p = 0.006) with a maximum in winter. Radius (p = 0.01) and ankle fractures (p ≤ 0.001) also occurred most frequently in winter. Non-bony lesions of the shoulder were significantly less in spring (p = 0.04). The DRGs showed no evidence of a monthly or seasonal clustering (p > 0.1). CONCLUSION: The significant clustering of injuries in specific months and seasons should lead to logistic consequences (e.g. operating room slots, availability of nursing and anesthesia staff). For a needs assessment the analysis of main diagnoses is more appropriate than DRGs.

[Multiplanar reconstruction with mobile 3D image intensifier. Surgical treatment of proximal humerus fractures]. / Multiplanare Rekonstruktion mit mobilem 3D-Bildwandler. Operative Versorgung proximaler Humerusfrakturen.

PURPOSE: The aim of this study was to analyze the applicability and advantages of the intraoperative use of a mobile 3D C-arm with multiplanar imaging for surgery of acute proximal humerus fractures. MATERIALS AND METHODS: In this study 20 patients (11 female, 9 male, median age 70 years, range 35-91 years) with dislocated proximal humerus fractures (6 with 2 segments, 10 with 3 segments and 4 with 4 segments) were included. Preoperatively 3D scanning was performed and a reevaluation of the fracture in comparison to the plain radiographs was performed. After operative treatment another scan was performed to evaluate technical complications. RESULTS: In comparison to the multiplanar reconstructions fracture morphology could not be correctly detected in 5 out of the 20 cases with plain radiographs. The preoperative image quality of the multiplanar reconstructions showed a significantly better assessment in comparison to the image quality with osteosynthesis (p < 0.05). The screws had to be replaced in 5 of the 20 patients. CONCLUSION: Intraoperative 3D imaging with mobile image intensifier enables an accurate analysis of fracture morphology. Furthermore a quasi real time preoperative planning, evaluation of reduction and implant position with immediate operative relevance can be realized.

[Seasonal distribution of diagnoses and DRG in trauma surgery]. / Saisonale Verteilung von Diagnosen und DRG in der Unfallchirurgie.

BACKGROUND: Recording DRGs and diagnoses allows their distribution to be shown over the course of the year. Thus, cumulative seasonal occurrence of diseases can be detected. PATIENTS AND METHODS: From 2004 to 2010 we recorded 22,293 main diagnoses and DRGs at the clinic for trauma surgery. Injuries with the same localization and treatment were pooled. RESULTS: The most frequent injuries were concussion, followed by spinal and lower leg fractures. They showed no seasonal accumulation. Proximal fractures of the humerus occurred approx. 25% more often in winter and ankle fractures about 33% more frequently. The diagnosis of osteoarthritis of the knee is twice as high in the winter as in the summer. CONCLUSION: It has to be verified if logistic conclusions of these results can lead to more efficiency in a hospital. The underlying analysis is applicable for every hospital and poses a valid controlling tool.

Intraoperative 3D imaging in intraarticular tibial plateau fractures - Does it help to improve the patients' outcomes?

BACKGROUND: In tibial plateau fractures (TPF) the restoration of an anatomical joint surface as well as an exact subchondral screw position for postoperative stability is crucial for the outcome. The aim of this study was to determine whether the additional use of an intraoperative 3D imaging intensifier (3D) might help to improve the outcome of complex TPF. METHODS: We performed a retrospective case-control study of a level 1 trauma center. Patients with AO/OTA 41 B3 and C-TPF operated on using a 3D imaging intensifier between November 2015 and December 2018 (3D group) were included. The outcomes of this patients were compared to patients operated without 3D imaging between January 2005 to December 2014 (2D group). The comparison of the groups was performed by matched pair analysis. The functional outcome of both groups was measured by KOOS and Lysholm Score after a follow-up period of at least 12 months. Operation time, infections and postoperative revisions were registered. RESULTS: In total, 18 patients were included in the 3D group (mean age: 51.0± 16.4 years; 12 females) and an equal number of matching partners from the 2D group (mean age: 50.3± 15.2 years; 11 females) were found (p=0.82; p=0.79). We found 9x B3, 2x C1, 1x C2, 6x C3 fractures according to AO/OTA for each group (p=1.00) with comparable ASA score (p=0.27). The mean operation time was 127.9± 45.9 min and 116.1± 45.7 min for the 3D and 2D group (p=0.28). The mean follow-up time was 20.9± 10.7 months for the 3D and 55.5± 34.7 months for the 2D group (p< 0.001). For the 3D group a mean Lysholm overall score of 67.4± 26.8 and KOOS overall score of 72.6± 23.5 could be assessed. In contrast, a mean Lysholm overall score of 62.0± 21.4 and KOOS overall score of 65.8± 21.6 could be measured in the 2D group (p=0.39; p=0.31). Thereby, functional outcome of the 3D group showed a significant higher KOOS Sport/Rec sub score of 54.7± 35.0 in comparison to the 2D group with 26.7± 31.6 (p= 0.01). Postoperative revisions had to be performed in 27.8% of cases in both groups (p=1.00). Due to the 3D imaging an intraoperative revision was performed in 33.3% (6/18). CONCLUSION: In our study we could show that re-reduction of the fracture or implant re-positioning were performed in relevant numbers based on the 3D imaging. This was associated with a midterm clinical benefit in regard to better KOOS Sport/Rec scores. TRIAL REGISTRATION: AZ 488 /20-ek.

[Lesser tuberosity avulsion in combination with multifragment fracture of the greater tuberosity. A rare entity at the proximal humerus]. / Kombinierte Tuberculum-minus-Avulsion mit Mehrfragmentfraktur des Tuberculum majus. Eine Rarität am proximalen Humerus.

Isolated fractures of the greater tuberosity represent 14-21% of all proximal humeral fractures. Lesser tuberosity fractures have mainly been mentioned in case reports. We report a rare case of a combination of a lesser tuberosity avulsion with a multifragment fracture of the greater tuberosity of the proximal humerus in a young man. The injury mechanism might be a complex interaction between abduction and external rotation with impaction and shearing against the glenoid and acromion.

Improved accuracy of K-wire positioning into the glenoid vault by intraoperative 3D image intensifier-based navigation for the glenoid component in shoulder arthroplasty.

INTRODUCTION: This article aimed to show that navigation, based on an intraoperative mobile 3D image intensifier, can improve the accuracy of central K-wire placement into the glenoid vault for glenoid component. HYPOTHESIS: The navigated k-wire placement is more accurate and shows a smaller deviation angle to the standard centerline compared to the classical "free hand technic". METHODS: In 34 fresh frozen sheep scapulae, 17 K-wire placements using the navigation (group 1) were compared with 17 using standard "face plane technique" (group 2). The relation to glenoid standard and alternative centerlines (CL) and the position within the glenoid vault were analyzed. RESULTS: In groups 1 and 2 the angle between the K-wire and standard CL was 2.2° and 4.7°, respectively (P=0.01). The angle between the K-wire and alternative CL was 14.4° for group 1 and 17.2° for group 2 (P=0.02). More navigated K-wire positions were identified within a 5mm corridor along the glenoid vault CL (52 vs. 39; P=0.004). DISCUSSION: Intraoperative 3D image intensifier-based navigation was more accurate and precise than standard K-wire placement. TYPE OF STUDY AND LEVEL OF PROOF: Basic science study, evidence level III.

[Clinical and radiological mid-term results after autologous osteochondral transplantation under consideration of quality of life]. / Mittelfristige klinische und radiologische Ergebnisse nach autologer osteochondraler Transplantation unter Berücksichtigung der Lebensqualität.

BACKGROUND: Treatment of full-thickness cartilage defects remains a challenge in musculoskeletal surgery. Autologous osteochondral transplantation represents a possible solution for the repair of affected areas. However, some problems like degenerative changes of the transplanted cylinders and the surrounding cartilage or lack of cylinder integration to the surrounding cartilage arise with this method. Thus mid-term results respecting the quality of life are useful for assessment of the method. PATIENTS/MATERIAL AND METHODS: We investigated 22 patients with a mean follow-up of 88 ± 14.5 months after autologous osteochondral transplantation due to a full-thickness cartilage defect of the medial femoral condyle. Beside clinical scores we assessed at follow-up the quality of life using the SF-36 health survey and the EQ-5D. Furthermore, radiological changes were detected and MRI was performed in 21 patients. A control group of 19 patients, treated with microfracture, was matched in terms of BMI, gender and age. Exclusion criteria for this group were tibial kissing lesion, ligament instability, arthrosis and malalignment. RESULTS: In a longitudinal comparison with results 13.5 months after operation, no difference in Lysholm score was found. In plain radiographs higher degrees of arthritic changes in the medial compartment compared to the unaffected knee were observed. MRI revealed a mean modified MOCART score of 41.2 ± 7.7 for the OAT group and of 39.4 ± 16.1 for the microfracture group, without being significant. For OAT patients all cylinders showed an osseous integration. However, cylinder oedema was found in 9 patients. Those patients had a higher intensity of pain on a visual analogue scale. Quality of life was better for OAT patients in the physical scale of SF-36, but not in the mental scale. CONCLUSION: Autologous osteochondral transplantation has an unaltered significance in treating full-thickness cartilage defects and leads to satisfying mid-term results. The development of early arthritic changes might not be preventable by this method. Oedema of the transplanted cylinders is attended by higher pain intensity and might be an indirect sign of cartilage degeneration.

[One- and two-stage procedure for revision after failure of anterior cruciate ligament reconstruction]. / Ein- und zweizeitiges Vorgehen bei Revisionschirurgie des vorderen Kreuzbandes.

AIM: Most surgeons favour a one-stage procedure for ACL revision surgery. Tunnel widening, limited range of motion or existent hardware can make a two-stage procedure necessary. Studies evaluating the results between both procedures are still lacking. Thus, we performed a prospective preliminary study comparing early results after one- and two-stage procedures for ACL revision reconstruction. METHOD: Between 1/2005 and 1/2006 21 patients were operated on for ACL revision. The follow-up period of the 4 women and 16 men was 12 months. One patient was excluded due to a juvenile osteoporosis. Median age was 34 years. All patients had a subjective instability, including 11 patients (55%) with a traumatic rerupture. The indication for a two-stage procedure depended on tunnel widening under consideration of tunnel placement, disturbing existing hardware and extension deficits. Eleven patients received a one-stage procedure while 9 patients were operated in a two-stage process. Seven received autogenous bone grafting. RESULTS: The preoperative tunnel diameter was for one-stage revisions (OS) femoral 7.9 +/- 1.8 mm and tibial 8.8 +/- 2.2 mm. For the two-stage (TS) procedure mean femoral tunnel was preoperatively 10.1 +/- 1.4 mm and tibial 12.1 +/- 1.4 mm. Femoral tunnel placement after revision (OS/TS) yielded a mean angle in anteroposterior view of 28.7 degrees /26.9 degrees and in the sagittal view most tunnels were placed in the dorsal quadrant. Tibial placement was in the sagittal view at 46.1%/46.9% in the anteroposterior direction and for mediolateral direction in the a. p. view at 44.2%/44.5%. Results for Lysholm score were 85.7/83.9 and for IKDC 73.6/76.4. The anterior tibial translation compared to the healthy side was 1.5 mm/1.8 mm. In one leg jumping patients obtained a distance of 83 %/86% of the healthy side and stated their pain on a VAS to be as low as 1.9/1.4 points. Both groups had similar ranges of motion as well. CONCLUSION: The success of ACL revision surgery crucially depends on preoperative planning and analysis. No functional or radiological differences could be observed between one- and two-stage procedures. Although the one-stage procedure might be favourable because of faster convalescence and shorter work incapacity, it should not be enforced at the price of an insufficient ACL.