Posteriorer Zugang zum Schultergelenk

Zusammenfassung : Operationsziel : Schonender Zugang zum posterioren Schultergelenkbereich. Indikationen : Posteriore Schulterstabilisation. Posteriorer Knochenaufbau/-spananlage des Glenoids. Korrekturosteotomie des Glenoids. Versorgung von Skapulahalsfrakturen. Versorgung von posterioren Glenoidrandfrakturen. Versorgung von Akromionfrakturen. Schulterarthrodese. Biopsien. Tumorentfernung. Relativ: Schulterendoprothese mit z.B. gleichzeitigem posterioren Glenoidaufbau. Relativ: Behandlung von Luxationsfrakturen des proximalen Humerus. Kontraindikationen : Allgemeine Kontraindikationen. Operationstechnik : In Seitenlagerung Aufsuchen der Landmarken: Spina scapulae und Akromion. Variabler Hautschnitt je nach zu versorgender Struktur: horizontal, über der Spina scapulae zentriert, bis schräg entlang der Margo lateralis scapulae, bis vertikal über dem Gelenk zentriert. Eigene Präferenz: Winkelhalbierende zwischen Spina scapulae und Margo lateralis scapulae. Von lateral (Subakromialraum) nach medial Ablösen des Musculus deltoideus mit einer kleinen Knochenschuppe von der Spina scapulae. Zum Glenoid: Eingehen zwischen Musculus infraspinatus (Nervus suprascapularis) und Musculus teres minor (Nervus axillaris). Zum Skapulahals (Achtung: Nervus axillaris identifizieren!): Eingehen zwischen Musculus teres minor (Nervus axillaris) und Musculus teres major (Nervus subscapularis) Falls eine Erweiterung des Zugangs erforderlich ist, ansatznahes Durchtrennen der Sehne des Musculus infraspinatus, welcher nach medial gehalten werden kann (cave: Nervus suprascapularis und Arteria circumflexa scapulae!). Weiterbehandlung : Entsprechend der zugrundeliegenden operierten Pathologie. Ergebnisse : Die Ergebnisse nach Operation über einen posterioren Zugang sind vor allem von der behandelten Pathologie abhängig. In der Klinik der Autoren wurden zwischen 1982 und 1995 24 Patienten (26 Schultern) mit posteriorer Instabilität durch einen offenen posteroinferioren Kaspelshift behandelt. Die durchschnittliche Nachuntersuchungszeit betrug 7,6 Jahre. Der alters- und geschlechtsadaptierte Constant- Murley-Score lag bei 91%. Subjektive Patientenbewertung: 24 Schultern gut bis sehr gut, zwei Schultern mäßig. Die Rezidivrate betrug 23% (alle Schultern waren voroperiert, oder es war ein erneutes, adäquates Trauma aufgetreten). Zugangskomplikationen (Schwäche oder Insuffizienz) wurden nicht beobachte

Elongation Patterns of Posterolateral Corner Reconstruction Techniques: Results Using 3-Dimensional Weightbearing Computed Tomography Simulation

Background The isometric characteristics of nonanatomic and anatomic posterolateral corner (PLC) reconstruction techniques under weightbearing conditions remain unclear. Purpose To (1) simulate graft elongation patterns during knee flexion for 3 different PLC reconstruction techniques (Larson, Arciero, and LaPrade) and (2) compute the most isometric insertion points of the fibular collateral ligament (FCL) graft strands for each technique and report quantitative radiographic landmarks. Study Design Descriptive laboratory study. Methods The authors performed a 3-dimensional simulation of 10 healthy knees from 0° to 120° of flexion using weightbearing computed tomography (CT) scans. The simulation was used to calculate ligament length changes during knee flexion for the PLC reconstruction techniques of Larson (nonanatomic single-bundle fibular sling reconstruction), Arciero (anatomic reconstruction with additional popliteofibular ligament graft strand), and LaPrade (anatomic reconstruction with popliteofibular ligament graft strand and popliteus tendon graft strand). The most isometric femoral insertion points for the FCL graft strands were computed within a 10-mm radius around the lateral epicondyle (LE), using an automatic string generation algorithm (0 indicating perfect isometry). Radiographic landmarks for the most isometric points were reported. Results Median graft lengthening during knee flexion was similar for the anterior graft strands of all 3 techniques. The posterior graft strands demonstrated significant differences, from lengthening for the Arciero (9.9 mm [range, 6.7 to 15.9 mm]) and LaPrade (10.2 mm [range, 4.1 to 19.7 mm]) techniques to shortening for the Larson technique (-17.1 mm [range, -9.3 to -22.3 mm]; P < .0010). The most isometric point for the FCL graft strands of all techniques was located at a median of 2.2 mm (range, -2.2 to 4.5 mm) posterior and 0.3 mm (range, -1.8 to 3.7 mm) distal to the LE. Conclusion Overconstraint can be avoided by tensioning the posterior graft strands in the Larson technique in extension, and in the Arciero and LaPrade techniques at a minimum of 60° of knee flexion. The most isometric point was located posterodistal to the LE. Clinical Relevance The described isometric behavior of nonanatomic and anatomic PLC reconstruction techniques can guide optimal surgical reconstruction and prevent graft lengthening and overconstraint of the lateral compartment in knee flexion. Repetitive graft lengthening has been found to be associated with graft failure, and overconstraint favors lateral compartment pressure and cartilage degeneration

Elongation Patterns of the Superficial Medial Collateral Ligament and the Posterior Oblique Ligament: A 3-Dimensional, Weightbearing Computed Tomography Simulation

Background Although length change patterns of the medial knee structures have been reported, either the weightbearing state was not considered or quantitative radiographic landmarks that allow the identification of the insertion sites were not reported. Purpose To (1) analyze the length changes of the superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL) under weightbearing conditions and (2) to identify the femoral sMCL insertion site that demonstrates the smallest length changes during knee flexion and report quantitative radiographic landmarks. Study Design Descriptive laboratory study. Methods The authors performed a 3-dimensional (3D) analysis of 10 healthy knees from 0° to 120° of knee flexion using weightbearing computed tomography (CT) scans. Ligament length changes of the sMCL and POL during knee flexion were analyzed using an automatic string generation algorithm. The most isometric femoral insertion of the sMCL that demonstrated the smallest length changes throughout the full range of motion (ROM) was identified. Radiographic landmarks were reported on an isometric grid defined by a true lateral view of the 3D CT model and transferred to a digitally reconstructed radiograph. Results The sMCL demonstrated small ligament length changes, and the POL demonstrated substantial shortening during knee flexion (P = .005). Shortening of the POL started from 30° of flexion. The most isometric femoral sMCL insertion was located 0.6 ± 1.7 mm posterior and 0.8 ± 1.2 mm inferior to the center of the sMCL insertion and prevented ligament length changes >5% during knee flexion in all participants. The insertion was located 47.8% ± 2.7% from the anterior femoral cortex and 46.3% ± 1.9% from the joint line on a true lateral 3D CT view. Conclusion The POL demonstrated substantial shortening starting from 30° of knee flexion and requires tightening near full extension to avoid overconstraint. Femoral sMCL graft placement directly posteroinferior to the center of the anatomical insertion of the sMCL demonstrated the most isometric behavior during knee flexion. Clinical Relevance The described elongation patterns of the sMCL and POL aid in guiding surgical medial knee reconstruction and preventing graft lengthening and overconstraint of the medial compartment. Repetitive graft lengthening is associated with graft failure, and overconstraint leads to increased compartment pressure, cartilage degeneration, and restricted ROM

The Relationship between Frontal, Axial Leg Alignment, and Ankle Joint Line Orientation-a Radiographic Analysis of Healthy Subjects

OBJECTIVE Ankle joint line orientation (AJLO) is influenced by the subtalar foot and frontal leg alignment. However, the influence of axial leg alignment on AJLO remains unclear. The study aimed to analyze the influence of frontal, axial leg alignment on AJLO in healthy subjects. METHODS Thirty healthy subjects (60 legs) without prior surgery underwent standing biplanar long leg radiograph (LLR) between 2016 and 2020. AJLO was measured in standing long-leg radiographs relative to the ground. Meary's angle and calcaneal pitch were measured. Hip-knee-ankle angle (HKA), femoral antetorsion, and tibial torsion were assessed with SterEOS software (EOS Imaging, Paris, France). LLR was acquired with the feet directing straight anteriorly, which corresponds to a neutral foot progression angle (FPA). The influence of subtalar, frontal, and axial alignment on AJLO was analyzed in a multiple regression model. RESULTS An increase in knee valgus increased relative valgus AJLO by 0.5° (95% CI: 0.2° to 0.7°) per 1° (P < 0.001). A decrease in femoral antetorsion increased relative valgus AJLO by 0.2° (95% CI: 0.1° to 0.2°) per 1° (P < 0.001), whereas Meary's angle and calcaneal pitch did not influence AJLO. CONCLUSION A link between frontal, axial leg alignment, and AJLO could be demonstrated, indicating that a valgus leg alignment and relative femoral retrotorsion are associated with an increase of valgus AJLO in healthy subjects when placing their feet in a neutral position. Alteration of the frontal, or rotational profile after realignment surgery or by implant positioning might influence the AJLO, when the FPA is kept constant

The winking sign is an indicator for increased femorotibial rotation in patients with recurrent patellar instability

Purpose: Rotation of the tibia relative to the femur was recently identified as a contributing risk factor for patellar instability, and correlated with its severity. The hypothesis was that in patellofemoral dysplastic knees, an increase in femorotibial rotation can be reliably detected on anteroposterior (AP) radiographs by an overlap of the lateral femoral condyle over the lateral tibial eminence. Methods: Sixty patients (77 knees) received low-dose computed tomography (CT) of the lower extremity for assessment of torsional malalignment due to recurrent patellofemoral instability. Three-dimensional (3D) surface models were created to assess femorotibial rotation and its relationship to other morphologic risk factors of patellofemoral instability. On weight-bearing AP knee radiographs, a femoral condyle/lateral tibial eminence superimposition was defined as a positive winking sign. Using digitally reconstructed radiographs of the 3D models, susceptibility of the winking sign to vertical/horizontal AP knee radiograph malrotation was investigated. Results: A positive winking sign was present in 30/77 knees (39.0%) and indicated a 6.3 ± 1.4° increase in femorotibial rotation (p 15°) with 43% sensitivity and 90% specificity (AUC = 0.72; p = 0.002). A positive winking sign (with 2 mm overlap) disappeared in case of a 10° horizontally or 15° vertically malrotated radiograph, whereas a 4 mm overlap did not disappear at all, regardless of the quality of the radiograph. In absence of a winking sign, on the other hand, no superimposition resulted within 20° of vertical/horizontal image malrotation. Femorotibial rotation was positively correlated to TT-TG (R2 = 0.40, p = 0.001) and patellar tilt (R2 = 0.30, p = 0.001). Conclusions: The winking sign reliably indicates an increased femorotibial rotation on a weight-bearing AP knee radiograph and could prove useful for day-by-day clinical work. Future research needs to investigate whether femorotibial rotation is not only a prognostic factor but a potential surgical target in patients with patellofemoral disorders. Level of evidence: III. Keywords: Femorotibial rotation; Knee rotation; Patellar instability; Winking sig

Kniegelenknahe Osteotomien: operative Planung mithilfe von CT-3-D-Analyse, patientenspezifischen Schnitt- und Korrekturblöcken

OBJECTIVE The goal of osteotomy is either to restore pretraumatic anatomic conditions or to shift the load to less affected compartments. INDICATIONS Indications for computer-assisted 3D analysis and the use of patient-specific osteotomy and reduction guides include "simple" deformities and, in particular, multidimensional complex (especially posttraumatic) deformities. CONTRAINDICATIONS General contraindications for performing a computed tomography (CT) scan or for an open approach for performing the surgery. SURGICAL TECHNIQUE Based on CT examinations of the affected and, if necessary, the contralateral healthy extremity as a healthy template (including hip, knee, and ankle joints), 3D computer models are generated, which are used for 3D analysis of the deformity as well as for calculation of the correction parameters. For the exact and simplified intraoperative implementation of the preoperative plan, individualized guides for the osteotomy and the reduction are produced by 3D printing. POSTOPERATIVE MANAGEMENT Partial weight-bearing from the first postoperative day. Increasing load after the first x‑ray control 6 weeks postoperatively. No limitation of the range of motion. RESULTS There are several studies that have analyzed the accuracy of the implementation of the planned correction for corrective osteotomies around the knee joint with the use of patient-specific instruments with promising results

The Orthopaedic forum 2011 Austrian-Swiss-German traveling fellowship tour summary

From January 31st to March 11th 2011 four traveling fellows representing the German speaking associated orthopaedic societies visited different academic orthopaedic centers in the U.K., Canada and the USA

Restoration of the patient-specific anatomy of the distal fibula based on a novel three-dimensional contralateral registration method

PURPOSE: Posttraumatic fibular malunion alters ankle joint biomechanics and may lead to pain, stiffness, and premature osteoarthritis. The accurate restoration is key for success of reconstructive surgeries. The aim of this study was to analyze the accuracy of a novel three-dimensional (3D) registration algorithm using different segments of the contralateral anatomy to restore the distal fibula. METHODS: Triangular 3D surface models were reconstructed from computed tomographic data of 96 paired lower legs. Four segments were defined: 25% tibia, 50% tibia, 75% fibula, and 75% fibula and tibia. A surface registration algorithm was used to superimpose the mirrored contralateral model on the original model. The accuracy of distal fibula restoration was measured. RESULTS: The median rotation error, 3D distance (Euclidean distance), and 3D angle (Euler's angle) using the distal 25% tibia segment for the registration were 0.8° (- 1.7-4.8), 2.1 mm (1.4-2.9), and 2.9° (1.9-5.4), respectively. The restoration showed the highest errors using the 75% fibula segment (rotation error 3.2° (0.1-8.3); Euclidean distance 4.2 mm (3.1-5.8); Euler's angle 5.8° (3.4-9.2)). The translation error did not differ significantly between segments. CONCLUSION: 3D registration of the contralateral tibia and fibula reliably approximated the premorbid anatomy of the distal fibula. Registration of the 25% distal tibia, including distinct anatomical landmarks of the fibular notch and malleolar colliculi, restored the anatomy with increasing accuracy, minimizing both rotational and translational errors. This new method of evaluating malreductions could reduce morbidity in patients with ankle fractures. LEVEL OF EVIDENCE: IV

Tibial internal rotation in combined anterior cruciate ligament and high-grade anterolateral ligament injury and its influence on ACL length

BACKGROUND Assessment of combined anterolateral ligament (ALL) and anterior cruciate ligament (ACL) injury remains challenging but of high importance as the ALL is a contributing stabilizer of tibial internal rotation. The effect of preoperative static tibial internal rotation on ACL -length remains unknown. The aim of the study was analyze the effect of tibial internal rotation on ACL length in single-bundle ACL reconstructions and to quantify tibial internal rotation in combined ACL and ALL injuries. METHODS The effect of tibial internal rotation on ACL length was computed in a three-dimensional (3D) model of 10 healthy knees with 5° increments of tibial internal rotation from 0 to 30° resulting in 70 simulations. For each step ACL length was measured. ALL injury severity was graded by a blinded musculoskeletal radiologist in a retrospective analysis of 61 patients who underwent single-bundle ACL reconstruction. Preoperative tibial internal rotation was measured in magnetic resonance imaging (MRI) and its diagnostic performance was analyzed. RESULTS ACL length linearly increased 0.7 ± 0.1 mm (2.1 ± 0.5% of initial length) per 5° of tibial internal rotation from 0 to 30° in each patient. Seventeen patients (27.9%) had an intact ALL (grade 0), 10 (16.4%) a grade 1, 21 (34.4%) a grade 2 and 13 (21.3%) a grade 3 injury of the ALL. Patients with a combined ACL and ALL injury grade 3 had a median static tibial internal rotation of 8.8° (interquartile range (IQR): 8.3) compared to 5.6° (IQR: 6.6) in patients with an ALL injury (grade 0-2) (p = 0.03). A cut-off > 13.3° of tibial internal rotation predicted a high-grade ALL injury with a specificity of 92%, a sensitivity of 30%; area under the curve (AUC) 0.70 (95% CI: 0.54-0.85) (p = 0.03) and an accuracy of 79%. CONCLUSION ACL length linearly increases with tibial internal rotation from 0 to 30°. A combined ACL and high-grade ALL injury was associated with greater preoperative tibial internal rotation. This potentially contributes to unintentional graft laxity in ACL reconstructed patients, in particular with concomitant high-grade ALL tears. STUDY DESIGN Cohort study; Level of evidence, 3