Bastian Scheiderer

How to avoid unintended valgus alignment in distal femoral derotational osteotomy for treatment of femoral torsional malalignment - a concept study

BackgroundDefining the optimal cutting plane for derotational osteotomy at the distal femur for correction of torsion in cases of patellofemoral instability is still challenging. This preliminary study investigates changes of frontal alignment by a simplified trigonometrical model and demonstrates a surgical guidance technique with the use of femur cadavers. The hypothesis was that regardless of midshaft bowing, a cutting plane perpendicular to the virtual anatomic shaft axis avoids unintended valgus malalignment due to derotation.MethodsA novel mathematical model, called the Pillar-Crane-Model, was developed to forecast changes on frontal alignment of the femur when a perpendicular cutting plane to the virtual anatomical shaft was chosen. As proof of concept, eight different torsion angles were assessed on two human cadaver femora (left and right). A single cut distal femoral osteotomy perpendicular to the virtual anatomical shaft was performed. Frontal plane alignment (mLDFA, aLDFA, AMA) was radiographically analyzed before and after rotation by 0°, 10°, 20°, and 30°. Measurements were compared to the model.ResultsThe trigonometrical equation from the Pillar-Crane-Model provides mathematical proof that slight changes into varus occur, seen by an increase in AMA and mLDFA, when the cutting plane is perpendicular to the virtual anatomical shaft axis. A table with standardized values is provided. Exemplarily, the specimens showed a mean increase of AMA from 4.8° to 6.3° and mLDFA from 85.2° to 86.7 after derotation by 30°. Throughout the derotation procedure, aLDFA remained at 80.4° ± 0.4°SD.ConclusionsWith the use of this model for surgical guidance and anatomic reference, unintended valgus changes on frontal malalignment can be avoided. When the cutting plane is considered to be perpendicular to the virtual anatomical shaft from a frontal and lateral view, a slight increase of mLDFA results when a derotational osteotomy of the distal femur is performed.

Derotational Osteotomy of the Distal Femur for the Treatment of Patellofemoral Instability Simultaneously Leads to the Correction of Frontal Alignment: A Laboratory Cadaveric Study

Background: Derotational osteotomy of the distal femur allows the anatomic treatment of patellofemoral maltracking due to increased femoral antetorsion. However, such rotational osteotomy procedures have a high potential of intended/unintended changes of frontal alignment. Purpose/Hypothesis: The purpose of this study was to perform derotational osteotomy of the distal femur and to demonstrate the utility of a novel trigonometric approach to address 3-dimensional (3D) changes on 2-dimensional imaging (axial computed tomography [CT] and frontal-plane radiography). The hypothesis was that 1-step single-cut osteotomy can simultaneously correct torsion and frontal alignment based on preoperatively calculated cutting angles. Study Design: Controlled laboratory study. Methods: Eight human cadaveric whole legs (4 lower limb torsos) underwent derotational osteotomy of the distal femur of 20°. A straight leg axis, determined as a mechanical femorotibial angle (mFTA) of 0°, was chosen as a goal for postoperative frontal alignment. The inclination of the cutting angle from the lateral view was calculated individually for each cadaveric leg and was represented by a simple 3D-printed cutting guide for surgery. Specimens underwent CT for the measurement of torsion, while the frontal leg axis was determined on an upright radiograph preoperatively and postoperatively. Preoperative and postoperative angles were compared with the mathematical prediction model. Results: The preoperative mFTA ranged from –3.9° (valgus) to +3.4° (varus) (mean, –0.2° ± 2.6°). A postoperative mean mFTA of 0.37° ± 0.69° (95% CI, –0.22° to 0.95°) was achieved (P = .01). Derotation showed a mean of 19.1° ± 2.1° (95% CI, 17.3°-20.8°). The oblique cutting plane for the correction of valgus legs showed a mean of 5.9° ± 6.8° and, for the correction of varus legs, a mean of –10.0° ± 4.5° projected on the perpendicular plane to the virtual anatomic shaft axis from the sagittal view. Conclusion: Single-cut distal femoral osteotomy can be performed to simultaneously address rotational as well as frontal alignment using a preoperatively defined oblique cut, as determined by the presented reproducible calculation model. Clinical Relevance: This study adds important knowledge to the technique of derotational osteotomy. This approach provides an individual, oblique single cut for the correction of torsion and frontal axis within a clinically insignificant margin. Simplified tables for calculation and a surgical reference make this model reproducible and safe.

Erratum to: Anatomic stabilization of chronic lateral instability of the ankle: Gold technique

Erratum to:Oper Orthop Traumatol 2017https://doi.org/10.1007/s00064-017-0513-9 The article was wrongly published under the article type “Review”. Please note that the article is an “Original Paper”.The publisher apologizes to the authors and …

Hat Ihr Patient einen „Werferellenbogen“?

Ein 19-jähriger Verwaltungskaufmann stellt sich mit Schmerzen im medialen Ellenbogengelenk vor. Diese treten vor allem beim Sport (semi-professioneller Baseball-Pitcher) auf, gelegentlich mit Parästhesien der Fingerspitzen. Ein Trauma sei ihm nicht erinnerlich.

Single cut distal femoral osteotomy for correction of femoral torsion and valgus malformity in patellofemoral malalignment - proof of application of new trigonometrical calculations and 3D-printed cutting guides

BackgroundThe purpose of this study was to perform a derotational osteotomy at the distal femur, as is done in cases of patellofemoral instability, and demonstrate the predictability of three-dimensional (3D) changes on axes in a cadaveric model by the use of a new mathematical approach.MethodsTen human cadaveric femurs, with increased antetorsion, underwent a visually observed derotational osteotomy at the distal femur by 20°, as is commonly done in clinics. For surgery, a single cut osteotomy with a defined cutting angle was calculated and given using a simple 3D-printed cutting guide per specimen, based on a newly-created trigonometrical model. To simulate post-operative straight frontal alignment in a normal range, a goal for the mechanical lateral distal femur angle (mLDFA) was set to 87.0° for five specimens (87-goal group) and 90.0° for five specimens (90-goal group). Specimens underwent pre- and post-operative radiographic analysis with CT scan for torsion and frontal plane x-ray for alignment measurements of mLDFA and anatomical mechanical angle (AMA).ResultsPerformed derotation showed a mean of 19.69° ±1.08°SD (95% CI: 18.91° to 20.47°). Regarding frontal alignment, a mean mLDFA of 86.9° ±0.66°SD (87-goal-group) and 90.42° ±0.25° SD (90-goal group), was observed (p = 0.008). Overall, the mean difference between intended mLDFA-goal and post-operatively achieved mLDFA was 0.14° ±0.56° SD (95% CI: -0.26° to 0.54°).ConclusionA preoperative calculated angle for single cut derotational osteotomy at the distal femur leads to a clinically precise post-operative result on torsion and frontal alignment when using this approach.

Clinical Outcomes, Tendon Integrity, and Shoulder Strength After Revision Rotator Cuff Reconstruction: A Minimum 2 Years’ Follow-up

Background: The retear rate after primary rotator cuff (RC) reconstruction is high and commonly leads to poorer clinical outcomes and shoulder function. In the case of primary failure, revision RC reconstruction (RCR) has become increasingly important to re-create RC integrity and improve outcomes. To date, clinical and structural outcomes after RCR have not been sufficiently investigated and described at midterm follow-up. Hypothesis/Purpose: The purpose was to evaluate the clinical and radiological outcomes after revision RCR. It was hypothesized that revision RCR significantly improves clinical outcomes and that the outcomes positively correlate with tendon integrity on magnetic resonance imaging (MRI). Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent revision RCR between 2008 and 2014 were retrospectively evaluated with a minimum follow-up of 2 years. Outcomes were assessed by a clinical examination, a visual analog scale for pain (VAS), the Constant Score (CS), the American Shoulder and Elbow Surgeons (ASES) score, and the Disabilities of the Arm, Shoulder and Hand (DASH) score. Tendon integrity was determined using 3-T MRI and graded according to the Sugaya classification. Results: Thirty-one of 40 patients (77.5%) were available for the final assessment at a mean follow-up of 50.3 ± 20.4 months. Clinical outcome scores significantly improved from preoperatively to postoperatively for the CS (39.7 ± 16.7 to 65.1 ± 19.7; P < .001), ASES (44.2 ± 17.7 to 75.2 ± 24.8; P < .001), and DASH (68.6 ± 15.1 to 21.5 ± 19.1; P < .001). The VAS score decreased from 6.1 ± 1.8 preoperatively to 1.3 ± 1.8 at final follow-up (P < .001). MRI demonstrated a retear rate of 55.5%. No differences in CS, ASES, and DASH scores were detected between patients with an intact repair and failure. Abduction strength was not significantly different in patients with an intact repair and retears (55.5 N vs 44.0 N, respectively, P = .52). Conclusion: Revision RCR improves clinical outcomes and shoulder function at midterm follow-up. The clinical outcome scores were comparable in patients with an intact repair and those with failed RC healing. Therefore, tendon integrity was not correlated with better clinical outcomes after revision RCR at final follow-up.

The V-Shaped Distal Triceps Tendon Repair: A Comparative Biomechanical Analysis:

Background: Restoring footprint anatomy, minimizing gap formation, and maximizing the strength of distal triceps tendon repairs are essential factors for a successful healing process and return to sport. Hypothesis: The novel V-shaped distal triceps tendon repair technique with unicortical button fixation closely restores footprint anatomy, provides minimal gap formation and high ultimate failure load, and minimizes iatrogenic fracture risk in acute/subacute distal triceps tendon tears. Study Design: Controlled laboratory study. Methods: Twenty-four cadaveric elbows (mean ± SD age, 66 ± 5 years) were randomly assigned to 1 of 3 repair groups: the transosseous cruciate repair technique (gold standard), the knotless suture-bridge repair technique, and the V-shaped distal triceps tendon repair technique. Anatomic measurements of the central triceps tendon footprint were obtained in all specimens with a 3-dimensional digitizer before and after the repair. Cyclic loading was performed for a total of 1500 cycles at a rate of 0.25 Hz, pulling in the direction of the triceps. Displacements were measured on the medial and lateral tendon sites with 2 differential variable reluctance transducers. Load to failure and construct failure mode were recorded. Results: The mean triceps bony insertion area was 399.05 ± 81.23 mm2. The transosseous cruciate repair technique restored 36.6% ± 16.8% of the native tendon insertion area, which was significantly different when compared with the knotless suture-bridge repair technique (85.2% ± 14.8%, P = .001) and the V-shaped distal triceps tendon repair technique (88.9% ± 14.8%, P = .002). Mean displacement showed no significant difference between the V-shaped distal triceps tendon repair technique (medial side, 0.75 ± 0.56 mm; lateral side, 0.99 ± 0.59 mm) and the knotless suture-bridge repair technique (1.61 ± 0.97 mm and 1.29 ± 0.8 mm) but significance between the V-shaped distal triceps tendon repair technique and the transosseous cruciate repair technique (4.91 ± 1.12 mm and 5.78 ± 0.9 mm, P < .001). Mean peak failure load of the V-shaped distal triceps tendon repair technique (732.1 ± 156.0 N) was significantly higher than that of the knotless suture-bridge repair technique (505.4 ± 173.9 N, P = .011) and the transosseous cruciate repair technique (281.1 ± 74.8 N, P < .001). Mechanism of failure differed among the 3 repairs, with the only olecranon fracture occurring in the knotless suture-bridge repair technique at the level of the lateral row suture anchors. Conclusion: At time zero, the V-shaped distal triceps tendon repair technique and the knotless suture-bridge repair technique both provided anatomic footprint coverage. Ultimate load to failure was highest for the V-shaped distal triceps tendon repair technique, while gap formation was different only in comparison with the transosseous cruciate repair technique. Clinical Relevance: The V-shaped distal triceps tendon repair technique provides an alternative procedure to other established repairs for acute/subacute distal triceps tendon ruptures. The reduced repair site motion of the V-shaped distal triceps tendon repair technique and the knotless suture-bridge repair technique at the time of surgery may allow a more aggressive rehabilitation program in the early postoperative period.

Relationship Between Deltoid and Rotator Cuff Muscles During Dynamic Shoulder Abduction: A Biomechanical Study of Rotator Cuff Tear Progression:

Background: Previous biomechanical studies regarding deltoid function during glenohumeral abduction have primarily used static testing protocols. Hypotheses: (1) Deltoid forces required for scapular plane abduction increase as simulated rotator cuff tears become larger, and (2) maximal abduction decreases despite increased deltoid forces. Study Design: Controlled laboratory study. Methods: Twelve fresh-frozen cadaveric shoulders with a mean age of 67 years (range, 64-74 years) were used. The supraspinatus and anterior, middle, and posterior deltoid tendons were attached to individual shoulder simulator actuators. Deltoid forces and maximum abduction were recorded for the following tear patterns: intact, isolated subscapularis (SSC), isolated supraspinatus (SSP), anterosuperior (SSP + SSC), posterosuperior (infraspinatus [ISP] + SSP), and massive (SSC + SSP + ISP). Optical triads tracked 3-dimensional motion during dynamic testing. Fluoroscopy and computed tomography were used to measure critical shoulder angle, acromial index, and superior humeral head migration with massive tears. Mean values for maximum glenohumeral abduction and deltoid forces were determined. Linear mixed-effects regression examined changes in motion and forces over time. Pearson product-moment correlation coefficients (r) among deltoid forces, critical shoulder angles, and acromial indices were calculated. Results: Shoulders with an intact cuff required 193.8 N (95% CI, 125.5 to 262.1) total deltoid force to achieve 79.8° (95% CI, 66.4° to 93.2°) of maximum glenohumeral abduction. Compared with native shoulders, abduction decreased after simulated SSP (–27.2%; 95% CI, –43.3% to –11.1%, P = .04), anterosuperior (–51.5%; 95% CI, –70.2% to –32.8%, P < .01), and massive (–48.4%; 95% CI, –65.2% to –31.5%, P < .01) cuff tears. Increased total deltoid forces were required for simulated anterosuperior (+108.1%; 95% CI, 68.7% to 147.5%, P < .01) and massive (+57.2%; 95% CI, 19.6% to 94.7%, P = .05) cuff tears. Anterior deltoid forces were significantly greater in anterosuperior (P < .01) and massive (P = .03) tears. Middle deltoid forces were greater with anterosuperior tears (P = .03). Posterior deltoid forces were greater with anterosuperior (P = .02) and posterosuperior (P = .04) tears. Anterior deltoid force was negatively correlated (r = −0.89, P = .01) with critical shoulder angle (34.3°; 95% CI, 32.0° to 36.6°). Deltoid forces had no statistical correlation with acromial index (0.55; 95% CI, 0.48 to 0.61). Superior migration was 8.3 mm (95% CI, 5.5 to 11.1 mm) during testing of massive rotator cuff tears. Conclusion: Shoulders with rotator cuff tears require considerable compensatory deltoid function to prevent abduction motion loss. Anterosuperior tears resulted in the largest motion loss despite the greatest increase in deltoid force. Clinical Relevance: Rotator cuff tears place more strain on the deltoid to prevent abduction motion loss. Fatigue or injury to the deltoid may result in a precipitous decline in abduction, regardless of tear size.

Superiore Kapselrekonstruktion@@@Superior capsule reconstruction: Grundlagen, Anatomie und Biomechanik@@@Principles, anatomy and biomechanics

ZusammenfassungDas bisherige Verständnis der Rekonstruktion der Rotatorenmanschette basiert auf der Wiederherstellung der tendoossären Einheit. In den vergangenen Jahren rückt jedoch die Bedeutung der superioren Kapsel in den therapeutischen Fokus. Diese wirkt als statischer Stabilisator einer superioren Translation des Humeruskopfes entgegen. Bei nichtrekonstruierbaren Verletzungen der superioren Rotatorenmanschette ist die darunterliegende Gelenkkapsel in der Regel mitbetroffen. Die superiore Kapselrekonstruktion scheint in diesen Fällen ein vielversprechendes Verfahren zur Wiederherstellung der glenohumeralen Biomechanik darzustellen und verbessert das klinische Outcome.AbstractHistorically, the concept of rotator cuff repair is the restoration of the tendon-bone unit; however, in recent years there has been growing interest in the role and therapeutic importance of the superior capsule. It functions as an important static stabilizer of the joint and resists superior translation of the humeral head. In case of irreparable lesions of the superior rotator cuff, the underlying joint capsule is consistently disrupted; therefore, reconstruction of the superior capsule seems to be a promising procedure for providing normal biomechanics of the glenohumeral joint and improving the clinical outcome.

Die geheilte Sehne

Ein 72-jähriger Patient stellte sichmit einer Fußheberschwäche links vor. Er gab an, diese v. a. bei längerem Gehen und Treppensteigen zu bemerken. Ein Stolpersturz vor 2 Monaten war eruierbar, welcher die Beschwerden ausgelöst habe. Schmerzen bestanden nicht. Nebenbefundlich befand sich der Patient zu diesem Zeitpunkt aufgrund eines Blasenkarzinoms in Behandlung, weshalb die Vorstellung verzögert erfolgte.