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Papers by Paul Borbas
Copyright © 2012 Paul Borbas et al. This is an open access article distributed under the Creative... more Copyright © 2012 Paul Borbas et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Adamantinoma is a low-grade, malignant biphasic bone tumour predominantly located in the tibia. In up to 50 % of all cases this is combined with one or more lesions in the ipsilateral fibula. Whether these lesions represent regional metastases or arise de novo is not yet exactly known. In order to address this question, we extracted DNA from the respective fresh frozen tumour tissues in a case of a young woman with a multifocal adamantinoma of both the tibia and ipsilateral fibula. Afterwards the X inactivation pattern was studied by means of methylation-sensitive polymerase chain reaction and primers that target the polymorphic CGG trinucleotide repeat of FMR1 gene and the polymorphic CAG repeat, on exon 1 of the human androgen recepto...
Journal of Shoulder and Elbow Surgery
Knee Surgery, Sports Traumatology, Arthroscopy
Purpose Upper third tears of the subscapularis tendon can be repaired successfully with a single ... more Purpose Upper third tears of the subscapularis tendon can be repaired successfully with a single anchor according to previous literature. The aim of the present study was to compare three single anchor repair techniques regarding fixation strength, footprint coverage and contact pressure in a biomechanical test setup on human cadaveric shoulders. Methods Eighteen human cadaveric shoulders were randomized in three groups with respect to the repair technique; group 1: knotted lasso-loop mattress, group 2: knotted mattress and group 3: knotless tape repair. Upper third tears of the subscapularis tendon (Lafosse type 2) were created and repairs were performed with additional contact pressure and area measurement using a pressure mapping system. Cyclic testing was performed by loading the subscapularis from 10 to 100 N for 300 cycles. A position-controlled ramp protocol up to 30 and 50 N was used to allow for pressure measurements. Finally, specimens were loaded to failure and failure modes were recorded. Results The three groups were not significantly different regarding age, gender, bone mineral density at the lesser tuberosity, subscapularis footprint size and defect area created at the upper subscapularis insertion. A significant difference was detected between group 1 (48.6 ± 13.8%) and group 2 (25.9 ± 5.7%) regarding pressurized footprint coverage (p = 0.028). Ultimate load to failure was 630.8 ± 145.3 N in group 1, 586.9 ± 220.7 N in group 2 and 678.2 ± 236.5 N in group 3, respectively. Cyclic displacement was similar in all three groups with an average displacement of 1.2 ± 0.6 mm. The highest stiffness was found in group 1 with 88 ± 30.3, which was not statistically significantly different to group 2 (65 ± 27 N/mm) and group 3 (83.9 ± 32.9 N/mm). The most common mode of failure was suture cut-through at the suture-tendon interface (44%). Failures in group 3 were less common associated with suture cut-through (33% vs. 50% in group 1 and 2), but no significant differences were found. Conclusions All three tested single anchor repair techniques of upper third subscapularis tears were able to provide sufficient biomechanical stability. Knotted lasso-loop mattress and knotless tape repair were superior regarding pressurized footprint coverage compared to a knotted horizontal mattress technique and are, therefore, preferable techniques for upper subscapularis repair.
Journal of Hand Surgery (European Volume)
We compared four methods of metacarpal shaft fixation: 2.2 mm intramedullary headless compression... more We compared four methods of metacarpal shaft fixation: 2.2 mm intramedullary headless compression screw; 3.0 mm intramedullary headless compression screw; intramedullary K-wire fixation; and dorsal plate fixation. Transverse mid-diaphyseal fractures were created in 64 metacarpal sawbones and were assigned into four groups. Peak load to failure and stiffness were measured in cantilever bending and torsion. We found that dorsal plating had the highest peak load to failure. However, initial bending stiffness of the 3.0 mm intramedullary headless compression screw was higher than that of the dorsal plates. In torsion testing, dorsal plating had the highest peak torque, but there was no significant difference in torsional stiffness between the plate and intramedullary headless compression screw constructs. We concluded that intramedullary headless compression screw fixation is biomechanically superior to K-wires in cantilever bending and torsion; however, it is less stable than dorsal pl...
BMC Musculoskeletal Disorders, 2021
Background Understanding muscle and tendon anatomy is of tremendous importance to achieve optimal... more Background Understanding muscle and tendon anatomy is of tremendous importance to achieve optimal surgical execution and results in tendon transfers around the shoulder. The aim of this study was to introduce and describe an additional distal muscle slip of the teres major (TM). Methods Sixteen fresh-frozen cadaver shoulders were dissected with the deltopectoral approach. The ventral latissimus dorsi (LD) tendon was harvested, and the shoulders were analyzed for the presence/absence of a distal teres major slip (dTMs) and its dimensions and relationship with the TM and LD tendons. Results The dTMs was identified in 12 shoulders (75%). It was always distal to the TM tendon and visible during the deltopectoral approach. There was a clear separation between the TM proximally and dTMs tendon distally. At the humeral insertion, both tendons had a common epimyseal sheet around the teres major and inserted continuously at the humerus. The mean width of the dTMs tendon at the insertion was ...
JSES International, 2021
Background Functional internal rotation (fIR) of the shoulder is frequently limited after reverse... more Background Functional internal rotation (fIR) of the shoulder is frequently limited after reverse shoulder arthroplasty (RTSA). The objective of this study was to study a cohort of satisfied patients after RTSA who had comparable active mobility except for fIR and to identify factors associated with selective loss of fIR. Methods A retrospective cohort study was conducted to compare 2 patient groups with either poor (≤ 2 points in the Constant-Murley score [CS]) or excellent (≥8 points in CS) fIR after RTSA at a minimum follow-up of 2 years. Influencing factors (demographic, surgical or implant related, radiographic parameters) and clinical outcome were analyzed. Results Fifty-two patients with a mean age of 72.8 (±9.3) and a mean follow-up of 41 months were included in the IR≤2 group and 63 patients with a mean age of 72.1 (±8.0) and a mean follow-up of 59 months in the IR≥8 group. All patients had undergone RTSA with the same implant type and only 2 different glenosphere sizes (36...
Archives of Orthopaedic and Trauma Surgery, 2021
Coronal plane fractures of the distal humerus are relatively rare and can be challenging to treat... more Coronal plane fractures of the distal humerus are relatively rare and can be challenging to treat due to their complexity and intra-articular nature. There is no gold standard for surgical management of these complex fractures. The purpose of this study was to compare the biomechanical stability and strength of two different internal fixation techniques for complex coronal plane fractures of the capitellum with posterior comminution. Fourteen fresh frozen, age- and gender-matched cadaveric elbows were 3D-navigated osteotomized simulating a Dubberley type IIB fracture. Specimens were randomized into one of two treatment groups and stabilized with an anterior antiglide plate with additional anteroposterior cannulated headless compression screws (group antiGP + HCS) or a posterolateral distal humerus locking plate with lateral extension (group PLP). Cyclic testing was performed with 75 N over 2000 cycles and ultimately until construct failure. Data were analyzed for displacement, const...
Arthroskopische Rotatorenmanschettenrekonstruktionen wurden initial mit einer einreihigen („singl... more Arthroskopische Rotatorenmanschettenrekonstruktionen wurden initial mit einer einreihigen („single row“) Technik beschrieben. Im Rahmen technischer Weiterentwicklungen der arthroskopischen Chirurgie wurden diverse Techniken zur zweireihigen („double row“), transossären und transossär-äquivalenten Sehnenfixation entwickelt, nicht zuletzt durch eine zunehmende Verbreitung knotenloser Anker. Die klinischen Ergebnisse zeigen keine relevanten Unterschiede zwischen den jeweiligen Techniken. Biomechanisch sind zweireihige Rekonstruktionen jedoch durch Vergrößerung der Kontaktfläche an der Insertionsstelle und der erreichten Stabilität überlegen, insbesondere mit medial geknoteten Fäden, welche in eine laterale Reihe als sog. Suture-Bridge abgespannt werden. Klassischerweise wurden Schraubanker aus Metall für eine arthroskopische Sehnenfixierung verwendet. Im Laufe der letzten Jahre wurde das Anker-Portfolio jedoch durch moderne bioresorbierbare und nichtresorbierbare (PEEK) Schraub- und Ei...
Journal of Orthopaedic Trauma
OBJECTIVES To assess both clinical and radiological long-term outcomes after hook plate osteosynt... more OBJECTIVES To assess both clinical and radiological long-term outcomes after hook plate osteosynthesis for Neer type II lateral clavicle fractures. DESIGN Retrospective Case Series SETTING:: Level 1 Trauma CenterPATIENTS/PARTICIPANTS: Patients who underwent open reduction internal fixation (ORIF) with a hook plate for displaced fractures of the lateral third of the clavicle (Neer type II) at a single trauma hospital were identified. INTERVENTION Lateral Clavicle ORIF with a hook plate MAIN OUTCOME MEASUREMENTS:: At the first of two long-term follow-up appointments, bilateral MRI scans and strength measurements were performed, Constant-Murley score (CS), subjective shoulder value (SSV) and Oxford Shoulder Score (OSS) of both shoulders were obtained. At the second follow-up, Specific AC score (SACS), SSV and OSS were obtained. RESULTS Twenty-one patients (mean age 29.5 years, ±9.7) could be included who were available for at least one of two follow-ups after 7.4 years (±2.3) and 13.9 years (±2.2). Bony union was achieved in all patients (100%) at an average of 3.4 months (±1.4). The hook plate was removed at an average of 5.5 months (±3.3) after initial surgery in all patients. No significant side-to-side differences were found in OSS, CS, SSV and SACS as well as for strength testing and MRI scans. CONCLUSIONS Long-term outcome after hook plate fixation of Neer type II lateral clavicle fractures demonstrated good clinical results and shoulder strength without higher radiographic rates of acromioclavicular joint osteoarthritis, subacromial impingement or rotator cuff lesions. That may be related to a standardized early plate removal after bony fracture union. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Arthroscopy, Sports Medicine, and Rehabilitation
Purpose To assess the mechanical properties, tendon resistance to suture cutout, and knot size of... more Purpose To assess the mechanical properties, tendon resistance to suture cutout, and knot size of a broad variety of high-strength sutures and tapes available for arthroscopic rotator cuff repair. Methods Nine different types of high-strength sutures and tapes for arthroscopic rotator cuff repair were studied: 6 were tapes (FiberTape, Hi-Fi Tape, Permatape, SutureTape, UltraTape, and XBraid TT), and 3 were sutures (Dynacord, FiberWire, and Ultrabraid). First, mechanical tensile testing of suture loops (n = 6) was performed. Second, the suture material was passed through an intact human cadaveric rotator cuff tendon (supraspinatus or infraspinatus), and cyclic as well as load-to-failure testing was performed, 8 times for each suture or tape. Statistical analysis of groups (tapes vs sutures) and between each suture and each tape was performed. Results Material testing revealed significant differences with superior mechanical properties of tapes compared with sutures regarding load for 3 mm of displacement (201 N vs 84 N, P < .0001), displacement at 200 N (3.6 mm vs 6.6 mm, P < .0001), stiffness (46 N/mm vs 25 N/mm, P < .0001), and ultimate load to failure (509 N vs 288 N, P < .0001). FiberTape showed the highest ultimate load to failure (805.5 ± 36.1 N), the highest load necessary for 3 mm of displacement (376.2 ± 19.1 N), and the lowest displacement at a 200-N load (2 ± 0.1 mm). Permatape had the highest stiffness (58.5 ± 5.3 N/mm). FiberTape had the highest knot height (9.5 ± 1.3 mm) and knot width (3.8 ± 0.7 mm) of a suture loop with 7 square knots. The typical failure mode in the cadaveric study part was tendon cut through. Conclusions Biomechanical in vitro testing showed that high-strength suture tapes compared with regular high-strength sutures have significantly better mechanical properties in both dry-laboratory testing and human cadaveric rotator cuff tendon pullout testing. FiberTape outperformed the other tapes and the sutures used in this analysis. Nonetheless, differences in tendon testing appeared to be less substantial than in dry-laboratory testing, and FiberTape had the highest knot height and width. Clinical Relevance FiberTape revealed the most favorable biomechanical performance in dry-laboratory and rotator cuff tendon testing. It may provide the best repair strength in vivo; however, it also has the largest knot size.
Archives of Orthopaedic and Trauma Surgery
The aim of the present biomechanical study was to evaluate the stability of a novel simple and co... more The aim of the present biomechanical study was to evaluate the stability of a novel simple and cost-effective mini-open double cow-hitch suture button technique of acromioclavicular (AC) joint stabilization in comparison to a well-established double tight-rope technique. A total of 12 fresh-frozen cadaveric shoulders were randomized into two treatment groups. In either a coracoclavicular stabilization with a standard double tight-rope technique (Group 1; n = 6, age 78 years ± 10) or a double cow-hitch with two No. 5 FiberWire strains looped in a bicortical button placed at the bottom of the coracoid process (Group 2; n = 6, age 80 years ± 13). Both techniques were equally augmented with an AC joint cerclage using a FiberTape. All shoulders were tested in a servo-hydraulic material testing machine for elongation/cyclic displacement (in mm) after cyclic loading (70 N cyclical load, 1500 cycles), stiffness (N/mm) and ultimate load to failure (N). The mechanism of failure was recorded. All tests were performed in a previously published testing setup. After 1500 cycles, group 2 showed a cyclic displacement of 1.67 mm (SD 0.85), compared to 1.04 mm (SD 0.23) cyclic displacement in group 1 (p = 0.11). The cyclic displacement after AC reconstruction in group 1 was 0.36 mm lower than in the native state with intact ligaments (p = 0.19), whereas the cyclic elongation in group 2 was 0.05 mm higher compared to the native situation (p = 0.87). Stiffness after reconstruction was significantly higher in group 1 compared to the native specimen (p = 0.001), in group 2 it was similar as before the reconstruction (p = 0.64). Ultimate load to failure and stiffness were higher in group 1 with 424 N (SD 237) and 68.6 N/mm (SD 8.2), compared to 377 N (SD 152) and 68 N/mm (SD 13.3) in group 2, without reaching statistical significance (p = 0.69 and 0.89). The most common failure modes were clavicular fractures at the tight rope drill holes (n = 2) and clavicular fractures medially at the fixation site (n = 2) in group 1, and coracoid button break-through (n = 3) and clavicular fractures medially at the fixation site (n = 2) in group 2. Stabilization of the AC joint with a novel mini-open double cow-hitch suture button technique resulted in a similar low elongation, high stiffness and ultimate load to failure compared to a double tight-rope technique. This cost-effective technique for AC joint stabilization could demonstrate a sufficient biomechanical stability with especially high stiffness and load-to-failure. Biomechanical study
Journal of Clinical Medicine
Reverse total shoulder arthroplasty (RTSA) is increasingly used for the treatment of complex prox... more Reverse total shoulder arthroplasty (RTSA) is increasingly used for the treatment of complex proximal humerus fractures and fracture sequelae. In 2021, half a dozen models of fracture stems are commercially available, reflecting its growing utility for fracture management. Prosthesis designs, bone grafting and tuberosity fixation techniques have evolved to allow better and more reliable fixation of tuberosities and bony ingrowth. Patients with anatomical tuberosity healing not only have an increased range of active anterior elevation and external rotation, but also experience fewer complications and longer prosthesis survival. This review provides an overview of recent evidence on basic and fracture-specific RTSA design features as well as tuberosity fixation techniques that can influence tuberosity healing.
Journal of Orthopaedic Research
We compared the construct stability of traditional knotted techniques with modern knotless anchor... more We compared the construct stability of traditional knotted techniques with modern knotless anchor systems used in arthroscopically assisted latissimus dorsi transfers (aLDTs) for irreparable posterosuperior rotator cuff tears. Eighteen cadaveric shoulders were age‐ and gender‐matched to the following three groups: knotted group (two knotted anchors); knotless group (two knotless anchors); and triple anchor group (two knotless anchors; one all‐suture anchor at the apex of the humeral head). All tendons were cyclically loaded in line of the aLDT over 400 cycles followed by a load to failure test. Outcome measures were the ultimate load to failure, elongation, construct stiffness, and failure modes. The triple anchor group revealed the highest ultimate load to failure (431 ± 78 N) compared with the knotted (326 ± 52 N; p = .022) and knotless (353 ± 105 N; p = .129) groups. Total elongation and construct stiffness were not significantly different comparing all three groups. The failure modes were: anchor pull‐out in all specimen of the knotted group; three (50%) anchor pull‐out and three suture pull‐out in the knotless group (p = .046); four (67%) anchor pull‐out, one (17%) suture pull‐out and one tendon pull‐out in the triple anchor group. Biomechanical analyses of knotless fixation techniques for aLDTs show similar construct stability and elongation compared with the traditional, knotted techniques. Bone fixation seems to be improved with the knotless anchor systems. In our practice, we continue to use the knotless fixation technique for aLDT and in the situation of weak, osteoporotic bone, we add a third (all‐suture) anchor to improve construct stability.
Journal of Shoulder and Elbow Surgery
Journal of Shoulder and Elbow Surgery
Journal of Shoulder and Elbow Surgery
The Bone & Joint Journal
Aims Conservative treatment of moderately displaced proximal humeral head fractures yields good c... more Aims Conservative treatment of moderately displaced proximal humeral head fractures yields good clinical results, but secondary fragment displacement may occur. Identification of those fractures at risk of displacement may influence initial decision-making. Methods A total of 163 shoulders in 162 patients with conservatively treated isolated proximal humeral fractures were included. The fractures occurred between January 2015 and May 2018. The mean age of the patients was 69 years (26 to 100) and the mean follow-up was 144 days (42 to 779). The fractures were classified according to Neer. Scores for osteoporosis (Tingart, Deltoid Tuberosity Index (DTI)) and osteoarthritis (OA) of the glenohumeral joint were assessed. Translation of the head on follow-up radiographs of more than 10 mm was defined as displacement. Eccentric head index (EHI) describes the offset of the humeral head centre in relation to the diaphyseal axis. The ratio was estimated on anteroposterior (AP) and Neer views...
Copyright © 2012 Paul Borbas et al. This is an open access article distributed under the Creative... more Copyright © 2012 Paul Borbas et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Adamantinoma is a low-grade, malignant biphasic bone tumour predominantly located in the tibia. In up to 50 % of all cases this is combined with one or more lesions in the ipsilateral fibula. Whether these lesions represent regional metastases or arise de novo is not yet exactly known. In order to address this question, we extracted DNA from the respective fresh frozen tumour tissues in a case of a young woman with a multifocal adamantinoma of both the tibia and ipsilateral fibula. Afterwards the X inactivation pattern was studied by means of methylation-sensitive polymerase chain reaction and primers that target the polymorphic CGG trinucleotide repeat of FMR1 gene and the polymorphic CAG repeat, on exon 1 of the human androgen recepto...
Journal of Shoulder and Elbow Surgery
Knee Surgery, Sports Traumatology, Arthroscopy
Purpose Upper third tears of the subscapularis tendon can be repaired successfully with a single ... more Purpose Upper third tears of the subscapularis tendon can be repaired successfully with a single anchor according to previous literature. The aim of the present study was to compare three single anchor repair techniques regarding fixation strength, footprint coverage and contact pressure in a biomechanical test setup on human cadaveric shoulders. Methods Eighteen human cadaveric shoulders were randomized in three groups with respect to the repair technique; group 1: knotted lasso-loop mattress, group 2: knotted mattress and group 3: knotless tape repair. Upper third tears of the subscapularis tendon (Lafosse type 2) were created and repairs were performed with additional contact pressure and area measurement using a pressure mapping system. Cyclic testing was performed by loading the subscapularis from 10 to 100 N for 300 cycles. A position-controlled ramp protocol up to 30 and 50 N was used to allow for pressure measurements. Finally, specimens were loaded to failure and failure modes were recorded. Results The three groups were not significantly different regarding age, gender, bone mineral density at the lesser tuberosity, subscapularis footprint size and defect area created at the upper subscapularis insertion. A significant difference was detected between group 1 (48.6 ± 13.8%) and group 2 (25.9 ± 5.7%) regarding pressurized footprint coverage (p = 0.028). Ultimate load to failure was 630.8 ± 145.3 N in group 1, 586.9 ± 220.7 N in group 2 and 678.2 ± 236.5 N in group 3, respectively. Cyclic displacement was similar in all three groups with an average displacement of 1.2 ± 0.6 mm. The highest stiffness was found in group 1 with 88 ± 30.3, which was not statistically significantly different to group 2 (65 ± 27 N/mm) and group 3 (83.9 ± 32.9 N/mm). The most common mode of failure was suture cut-through at the suture-tendon interface (44%). Failures in group 3 were less common associated with suture cut-through (33% vs. 50% in group 1 and 2), but no significant differences were found. Conclusions All three tested single anchor repair techniques of upper third subscapularis tears were able to provide sufficient biomechanical stability. Knotted lasso-loop mattress and knotless tape repair were superior regarding pressurized footprint coverage compared to a knotted horizontal mattress technique and are, therefore, preferable techniques for upper subscapularis repair.
Journal of Hand Surgery (European Volume)
We compared four methods of metacarpal shaft fixation: 2.2 mm intramedullary headless compression... more We compared four methods of metacarpal shaft fixation: 2.2 mm intramedullary headless compression screw; 3.0 mm intramedullary headless compression screw; intramedullary K-wire fixation; and dorsal plate fixation. Transverse mid-diaphyseal fractures were created in 64 metacarpal sawbones and were assigned into four groups. Peak load to failure and stiffness were measured in cantilever bending and torsion. We found that dorsal plating had the highest peak load to failure. However, initial bending stiffness of the 3.0 mm intramedullary headless compression screw was higher than that of the dorsal plates. In torsion testing, dorsal plating had the highest peak torque, but there was no significant difference in torsional stiffness between the plate and intramedullary headless compression screw constructs. We concluded that intramedullary headless compression screw fixation is biomechanically superior to K-wires in cantilever bending and torsion; however, it is less stable than dorsal pl...
BMC Musculoskeletal Disorders, 2021
Background Understanding muscle and tendon anatomy is of tremendous importance to achieve optimal... more Background Understanding muscle and tendon anatomy is of tremendous importance to achieve optimal surgical execution and results in tendon transfers around the shoulder. The aim of this study was to introduce and describe an additional distal muscle slip of the teres major (TM). Methods Sixteen fresh-frozen cadaver shoulders were dissected with the deltopectoral approach. The ventral latissimus dorsi (LD) tendon was harvested, and the shoulders were analyzed for the presence/absence of a distal teres major slip (dTMs) and its dimensions and relationship with the TM and LD tendons. Results The dTMs was identified in 12 shoulders (75%). It was always distal to the TM tendon and visible during the deltopectoral approach. There was a clear separation between the TM proximally and dTMs tendon distally. At the humeral insertion, both tendons had a common epimyseal sheet around the teres major and inserted continuously at the humerus. The mean width of the dTMs tendon at the insertion was ...
JSES International, 2021
Background Functional internal rotation (fIR) of the shoulder is frequently limited after reverse... more Background Functional internal rotation (fIR) of the shoulder is frequently limited after reverse shoulder arthroplasty (RTSA). The objective of this study was to study a cohort of satisfied patients after RTSA who had comparable active mobility except for fIR and to identify factors associated with selective loss of fIR. Methods A retrospective cohort study was conducted to compare 2 patient groups with either poor (≤ 2 points in the Constant-Murley score [CS]) or excellent (≥8 points in CS) fIR after RTSA at a minimum follow-up of 2 years. Influencing factors (demographic, surgical or implant related, radiographic parameters) and clinical outcome were analyzed. Results Fifty-two patients with a mean age of 72.8 (±9.3) and a mean follow-up of 41 months were included in the IR≤2 group and 63 patients with a mean age of 72.1 (±8.0) and a mean follow-up of 59 months in the IR≥8 group. All patients had undergone RTSA with the same implant type and only 2 different glenosphere sizes (36...
Archives of Orthopaedic and Trauma Surgery, 2021
Coronal plane fractures of the distal humerus are relatively rare and can be challenging to treat... more Coronal plane fractures of the distal humerus are relatively rare and can be challenging to treat due to their complexity and intra-articular nature. There is no gold standard for surgical management of these complex fractures. The purpose of this study was to compare the biomechanical stability and strength of two different internal fixation techniques for complex coronal plane fractures of the capitellum with posterior comminution. Fourteen fresh frozen, age- and gender-matched cadaveric elbows were 3D-navigated osteotomized simulating a Dubberley type IIB fracture. Specimens were randomized into one of two treatment groups and stabilized with an anterior antiglide plate with additional anteroposterior cannulated headless compression screws (group antiGP + HCS) or a posterolateral distal humerus locking plate with lateral extension (group PLP). Cyclic testing was performed with 75 N over 2000 cycles and ultimately until construct failure. Data were analyzed for displacement, const...
Arthroskopische Rotatorenmanschettenrekonstruktionen wurden initial mit einer einreihigen („singl... more Arthroskopische Rotatorenmanschettenrekonstruktionen wurden initial mit einer einreihigen („single row“) Technik beschrieben. Im Rahmen technischer Weiterentwicklungen der arthroskopischen Chirurgie wurden diverse Techniken zur zweireihigen („double row“), transossären und transossär-äquivalenten Sehnenfixation entwickelt, nicht zuletzt durch eine zunehmende Verbreitung knotenloser Anker. Die klinischen Ergebnisse zeigen keine relevanten Unterschiede zwischen den jeweiligen Techniken. Biomechanisch sind zweireihige Rekonstruktionen jedoch durch Vergrößerung der Kontaktfläche an der Insertionsstelle und der erreichten Stabilität überlegen, insbesondere mit medial geknoteten Fäden, welche in eine laterale Reihe als sog. Suture-Bridge abgespannt werden. Klassischerweise wurden Schraubanker aus Metall für eine arthroskopische Sehnenfixierung verwendet. Im Laufe der letzten Jahre wurde das Anker-Portfolio jedoch durch moderne bioresorbierbare und nichtresorbierbare (PEEK) Schraub- und Ei...
Journal of Orthopaedic Trauma
OBJECTIVES To assess both clinical and radiological long-term outcomes after hook plate osteosynt... more OBJECTIVES To assess both clinical and radiological long-term outcomes after hook plate osteosynthesis for Neer type II lateral clavicle fractures. DESIGN Retrospective Case Series SETTING:: Level 1 Trauma CenterPATIENTS/PARTICIPANTS: Patients who underwent open reduction internal fixation (ORIF) with a hook plate for displaced fractures of the lateral third of the clavicle (Neer type II) at a single trauma hospital were identified. INTERVENTION Lateral Clavicle ORIF with a hook plate MAIN OUTCOME MEASUREMENTS:: At the first of two long-term follow-up appointments, bilateral MRI scans and strength measurements were performed, Constant-Murley score (CS), subjective shoulder value (SSV) and Oxford Shoulder Score (OSS) of both shoulders were obtained. At the second follow-up, Specific AC score (SACS), SSV and OSS were obtained. RESULTS Twenty-one patients (mean age 29.5 years, ±9.7) could be included who were available for at least one of two follow-ups after 7.4 years (±2.3) and 13.9 years (±2.2). Bony union was achieved in all patients (100%) at an average of 3.4 months (±1.4). The hook plate was removed at an average of 5.5 months (±3.3) after initial surgery in all patients. No significant side-to-side differences were found in OSS, CS, SSV and SACS as well as for strength testing and MRI scans. CONCLUSIONS Long-term outcome after hook plate fixation of Neer type II lateral clavicle fractures demonstrated good clinical results and shoulder strength without higher radiographic rates of acromioclavicular joint osteoarthritis, subacromial impingement or rotator cuff lesions. That may be related to a standardized early plate removal after bony fracture union. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Arthroscopy, Sports Medicine, and Rehabilitation
Purpose To assess the mechanical properties, tendon resistance to suture cutout, and knot size of... more Purpose To assess the mechanical properties, tendon resistance to suture cutout, and knot size of a broad variety of high-strength sutures and tapes available for arthroscopic rotator cuff repair. Methods Nine different types of high-strength sutures and tapes for arthroscopic rotator cuff repair were studied: 6 were tapes (FiberTape, Hi-Fi Tape, Permatape, SutureTape, UltraTape, and XBraid TT), and 3 were sutures (Dynacord, FiberWire, and Ultrabraid). First, mechanical tensile testing of suture loops (n = 6) was performed. Second, the suture material was passed through an intact human cadaveric rotator cuff tendon (supraspinatus or infraspinatus), and cyclic as well as load-to-failure testing was performed, 8 times for each suture or tape. Statistical analysis of groups (tapes vs sutures) and between each suture and each tape was performed. Results Material testing revealed significant differences with superior mechanical properties of tapes compared with sutures regarding load for 3 mm of displacement (201 N vs 84 N, P < .0001), displacement at 200 N (3.6 mm vs 6.6 mm, P < .0001), stiffness (46 N/mm vs 25 N/mm, P < .0001), and ultimate load to failure (509 N vs 288 N, P < .0001). FiberTape showed the highest ultimate load to failure (805.5 ± 36.1 N), the highest load necessary for 3 mm of displacement (376.2 ± 19.1 N), and the lowest displacement at a 200-N load (2 ± 0.1 mm). Permatape had the highest stiffness (58.5 ± 5.3 N/mm). FiberTape had the highest knot height (9.5 ± 1.3 mm) and knot width (3.8 ± 0.7 mm) of a suture loop with 7 square knots. The typical failure mode in the cadaveric study part was tendon cut through. Conclusions Biomechanical in vitro testing showed that high-strength suture tapes compared with regular high-strength sutures have significantly better mechanical properties in both dry-laboratory testing and human cadaveric rotator cuff tendon pullout testing. FiberTape outperformed the other tapes and the sutures used in this analysis. Nonetheless, differences in tendon testing appeared to be less substantial than in dry-laboratory testing, and FiberTape had the highest knot height and width. Clinical Relevance FiberTape revealed the most favorable biomechanical performance in dry-laboratory and rotator cuff tendon testing. It may provide the best repair strength in vivo; however, it also has the largest knot size.
Archives of Orthopaedic and Trauma Surgery
The aim of the present biomechanical study was to evaluate the stability of a novel simple and co... more The aim of the present biomechanical study was to evaluate the stability of a novel simple and cost-effective mini-open double cow-hitch suture button technique of acromioclavicular (AC) joint stabilization in comparison to a well-established double tight-rope technique. A total of 12 fresh-frozen cadaveric shoulders were randomized into two treatment groups. In either a coracoclavicular stabilization with a standard double tight-rope technique (Group 1; n = 6, age 78 years ± 10) or a double cow-hitch with two No. 5 FiberWire strains looped in a bicortical button placed at the bottom of the coracoid process (Group 2; n = 6, age 80 years ± 13). Both techniques were equally augmented with an AC joint cerclage using a FiberTape. All shoulders were tested in a servo-hydraulic material testing machine for elongation/cyclic displacement (in mm) after cyclic loading (70 N cyclical load, 1500 cycles), stiffness (N/mm) and ultimate load to failure (N). The mechanism of failure was recorded. All tests were performed in a previously published testing setup. After 1500 cycles, group 2 showed a cyclic displacement of 1.67 mm (SD 0.85), compared to 1.04 mm (SD 0.23) cyclic displacement in group 1 (p = 0.11). The cyclic displacement after AC reconstruction in group 1 was 0.36 mm lower than in the native state with intact ligaments (p = 0.19), whereas the cyclic elongation in group 2 was 0.05 mm higher compared to the native situation (p = 0.87). Stiffness after reconstruction was significantly higher in group 1 compared to the native specimen (p = 0.001), in group 2 it was similar as before the reconstruction (p = 0.64). Ultimate load to failure and stiffness were higher in group 1 with 424 N (SD 237) and 68.6 N/mm (SD 8.2), compared to 377 N (SD 152) and 68 N/mm (SD 13.3) in group 2, without reaching statistical significance (p = 0.69 and 0.89). The most common failure modes were clavicular fractures at the tight rope drill holes (n = 2) and clavicular fractures medially at the fixation site (n = 2) in group 1, and coracoid button break-through (n = 3) and clavicular fractures medially at the fixation site (n = 2) in group 2. Stabilization of the AC joint with a novel mini-open double cow-hitch suture button technique resulted in a similar low elongation, high stiffness and ultimate load to failure compared to a double tight-rope technique. This cost-effective technique for AC joint stabilization could demonstrate a sufficient biomechanical stability with especially high stiffness and load-to-failure. Biomechanical study
Journal of Clinical Medicine
Reverse total shoulder arthroplasty (RTSA) is increasingly used for the treatment of complex prox... more Reverse total shoulder arthroplasty (RTSA) is increasingly used for the treatment of complex proximal humerus fractures and fracture sequelae. In 2021, half a dozen models of fracture stems are commercially available, reflecting its growing utility for fracture management. Prosthesis designs, bone grafting and tuberosity fixation techniques have evolved to allow better and more reliable fixation of tuberosities and bony ingrowth. Patients with anatomical tuberosity healing not only have an increased range of active anterior elevation and external rotation, but also experience fewer complications and longer prosthesis survival. This review provides an overview of recent evidence on basic and fracture-specific RTSA design features as well as tuberosity fixation techniques that can influence tuberosity healing.
Journal of Orthopaedic Research
We compared the construct stability of traditional knotted techniques with modern knotless anchor... more We compared the construct stability of traditional knotted techniques with modern knotless anchor systems used in arthroscopically assisted latissimus dorsi transfers (aLDTs) for irreparable posterosuperior rotator cuff tears. Eighteen cadaveric shoulders were age‐ and gender‐matched to the following three groups: knotted group (two knotted anchors); knotless group (two knotless anchors); and triple anchor group (two knotless anchors; one all‐suture anchor at the apex of the humeral head). All tendons were cyclically loaded in line of the aLDT over 400 cycles followed by a load to failure test. Outcome measures were the ultimate load to failure, elongation, construct stiffness, and failure modes. The triple anchor group revealed the highest ultimate load to failure (431 ± 78 N) compared with the knotted (326 ± 52 N; p = .022) and knotless (353 ± 105 N; p = .129) groups. Total elongation and construct stiffness were not significantly different comparing all three groups. The failure modes were: anchor pull‐out in all specimen of the knotted group; three (50%) anchor pull‐out and three suture pull‐out in the knotless group (p = .046); four (67%) anchor pull‐out, one (17%) suture pull‐out and one tendon pull‐out in the triple anchor group. Biomechanical analyses of knotless fixation techniques for aLDTs show similar construct stability and elongation compared with the traditional, knotted techniques. Bone fixation seems to be improved with the knotless anchor systems. In our practice, we continue to use the knotless fixation technique for aLDT and in the situation of weak, osteoporotic bone, we add a third (all‐suture) anchor to improve construct stability.
Journal of Shoulder and Elbow Surgery
Journal of Shoulder and Elbow Surgery
Journal of Shoulder and Elbow Surgery
The Bone & Joint Journal
Aims Conservative treatment of moderately displaced proximal humeral head fractures yields good c... more Aims Conservative treatment of moderately displaced proximal humeral head fractures yields good clinical results, but secondary fragment displacement may occur. Identification of those fractures at risk of displacement may influence initial decision-making. Methods A total of 163 shoulders in 162 patients with conservatively treated isolated proximal humeral fractures were included. The fractures occurred between January 2015 and May 2018. The mean age of the patients was 69 years (26 to 100) and the mean follow-up was 144 days (42 to 779). The fractures were classified according to Neer. Scores for osteoporosis (Tingart, Deltoid Tuberosity Index (DTI)) and osteoarthritis (OA) of the glenohumeral joint were assessed. Translation of the head on follow-up radiographs of more than 10 mm was defined as displacement. Eccentric head index (EHI) describes the offset of the humeral head centre in relation to the diaphyseal axis. The ratio was estimated on anteroposterior (AP) and Neer views...