Hip Capsular Closure: A Biomechanical Analysis of Failure Torque

Background: Hip capsulotomy is routinely performed during arthroscopic surgery to achieve adequate exposure of the joint. Iatrogenic instability can result after hip arthroscopic surgery because of capsular insufficiency, which can be avoided with effective closure of the hip capsule. There is currently no consensus in the literature regarding the optimal quantity of sutures upon capsular closure to achieve maximal stability postoperatively. Purpose/Hypothesis: The purpose of this study was to determine the failure torques of 1-, 2-, and 3-suture constructs for hip capsular closure to resist external rotation and extension after standard anterosuperior interportal capsulotomy (12 to 3 o’clock). Additionally, the degree of external rotation at which the suture constructs failed was recorded. The null hypothesis of this study was that no significant differences with respect to the failure torque would be found between the 3 repair constructs. Study Design: Controlled laboratory study. Methods: Nine pairs (n = 18) of fresh-frozen human cadaveric hemipelvises underwent anterosuperior interportal capsulotomy, which were repaired with 1, 2, or 3 side-to-side sutures. Each hip was secured in a dynamic biaxial testing machine and underwent a cyclic external rotation preconditioning protocol, followed by external rotation to failure. Results: The failure torque of the 1-suture hip capsular closure construct was significantly less than that of the 3-suture construct. The median failure torque for the 1-suture construct was 67.4 N·m (range, 47.4-73.6 N·m). The median failure torque was 85.7 N·m (range, 56.9-99.1 N·m) for the 2-suture construct and 91.7 N·m (range, 74.7-99.0 N·m) for the 3-suture construct. All 3 repair constructs exhibited a median 36° (range, 22°-64°) of external rotation at the failure torque. Conclusion: The most important finding of this study was that the 2- and 3-suture constructs resulted in comparable biomechanical failure torques when external rotation forces were applied to conventional hip capsulotomy in a cadaveric model. The 3-suture construct was significantly stronger than the 1-suture construct; however, there was not a significant difference between the 2- and 3-suture constructs. Additionally, all constructs failed at approximately 36° of external rotation. Clinical Relevance: Re-establishing the native anatomy of the hip capsule after hip arthroscopic surgery has been reported to result in improved outcomes and reduce the risk of iatrogenic instability. Therefore, adequate capsular closure is important to restore proper hip biomechanics, and postoperative precautions limiting external rotation should be utilized to protect the repair.

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Hip Capsular Closure

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967117s00110 ◽

2017 ◽

Vol 5 (3_suppl3) ◽

pp. 2325967117S0011

Author(s):

Jorge Chahla ◽

Jacob D. Mikula ◽

Jason M. Schon ◽

Chase S. Dean ◽

Kimi Dahl ◽

...

Keyword(s):

Hip Arthroscopy ◽

External Rotation ◽

Testing Machine ◽

Early Postoperative Period ◽

Biaxial Testing ◽

Type 1 Error ◽

Significant Difference ◽

Fresh Frozen ◽

Hip Capsule ◽

The One

Objectives: Iatrogenic instability can result after hip arthroscopy due to capsular insufficiency, which can be avoided with an effective closure of the hip capsule. There is currently no consensus in the literature regarding the optimal quantity of sutures upon capsular closure to achieve maximal stability postoperatively. The objective of this study was to determine the strength of one-, two-, and three-suture constructs for hip capsular closure to resist external rotation and extension following a standard anterosuperior inter-portal capsulotomy (12 to 3 o’clock). Additionally, the degree of external rotation at which the suture constructs failed was recorded. Methods: Nine pairs ( n = 18) of fresh-frozen human cadaveric hemi-pelvises underwent anterosuperior inter-portal capsulotomies, which were repaired with one, two, or three side-to-side sutures. Each hip was secured in a dynamic, biaxial testing machine and underwent a cyclic external rotation preconditioning protocol followed by external rotation to failure ( Figure 1 ). The non-parametric version of the BIBD ANOVA analysis (Durbin test) was used to assess the primary hypothesis that different suture numbers are associated with different torque capacities. When the omnibus Durbin test was statistically significant, post-hoc comparisons were made using Conover’s method, and the Holm-Bonferroni method was used to control the type-1 error. Group medians and ranges were reported. Significance was set at p < 0.05. [Figure: see text] Results: The failure torque of a one-suture hip capsular closure construct was significantly less than the three-suture construct. The failure torque for the one-suture construct was 67.4 N-m (range: 47.4 - 73.6 N-m). For two sutures, the failure torque was 85.7 N-m (range: 56.9 - 99.1 N-m) and for three sutures the failure torque was 91.7 N-m (range: 74.7 - 99.0 N-m). Repair constructs exhibited 36º (range: 22° - 64°) of external rotation at failure torque. Conclusion: The most important finding of this study was that three sutures provided the strongest biomechanical construct, demonstrating a median maximum torque of nearly 91.7 N-m. A three-suture construct was significantly stronger than one suture; however, there was not a significant difference between two- and three-suture constructs. Additionally, constructs failed at approximately 35° of external rotation, providing an important guideline for appropriate rehabilitation to protect the capsular repair in the early postoperative period. Reestablishing the native anatomy of the hip capsule following hip arthroscopy has been reported to result in improved outcomes and reduce the risk of iatrogenic instability. Therefore, an adequate capsular closure is important to restore proper hip biomechanics, and postoperative precautions limiting external rotation should be utilized to protect the repair. [Figure: see text]

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Biomechanical Analysis of Crossed Pinning Construct on Supracondylar Fracture of Humerus in Children: Does Point of Crossing Matters?

IIUM Medical Journal Malaysia ◽

10.31436/imjm.v17i1.825 ◽

2018 ◽

Vol 17 (1) ◽

Author(s):

Mohd Aizat Azfar Bin Soldin ◽

Mohd Shukrimi bin Awang ◽

Ardilla Hanim Binti Razak

Keyword(s):

External Rotation ◽

Biomechanical Analysis ◽

Point Location ◽

Recommended Treatment ◽

Pin Fixation ◽

Supracondylar Humerus Fractures ◽

Significant Difference ◽

Humerus Fractures ◽

The Stability ◽

Crossing Point

Introduction: Percutaneous pin fixation either by crossed pinning construct (CPC) or lateral divergent pinning construct (LDPC) are the recommended treatment for displaced supracondylar humerus fractures (SCHF) in children. Several studies had compared the biomechanical stability between these two, however, a biomechanical analysis of varying crossing point location in CPC has not been performed previously. The aim of this study was to compare the stability of various crossing point location in CPC and LDPC. Materials and Methods: Thirty synthetic humeri were osteotomized at mid olecranon fossa, anatomically reduced and pinned using two 1.6 mm Kirschner wiresin five different constructs namely centre point, medial point, lateral point, superior point and LDPC. Six samples were prepared for each construct and were tested for extension, flexion, valgus, varus, internal rotation and external rotation forces by using Universal Tensile Machine and the data were analysed with R Statistic. Results: The centre point CPC was the stiffest while the LDPC and medial point CPC were the least stiff construct for linear and rotational force respectively. Lateral point CPC, and superior point CPC showed no statistically significant difference when compared to centre point CPC. Conclusion: The centre point CPC was the most stable construct while the LDPC and medial point CPC were the least stable. The stability of lateral point CPC and superior point CPC were statistically comparable to centre point CPC. Clinically, this will help the treating surgeon to reduce the numbers of attempt during K-wire insertion in order to get perfect centre point CPC.

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Biomechanical Analysis of Conventional Partially Threaded Screws Versus Headless Compression Screws in Proximal Fifth Metatarsal (Jones) Fracture Fixation

Foot & Ankle Specialist ◽

10.1177/1938640020931668 ◽

2020 ◽

pp. 193864002093166

Author(s):

Kenrick Lam ◽

Roger Bui ◽

Randal Morris ◽

Vinod Panchbhavi

Keyword(s):

Biomechanical Analysis ◽

Therapeutic Level ◽

Compression Screw ◽

Significant Difference ◽

Headless Compression Screws ◽

Fresh Frozen ◽

Cantilever Bending ◽

Fracture Stiffness ◽

Intramedullary Screw ◽

Cadaveric Model

Background. Intramedullary screw fixation of Jones fractures using partially threaded screws is a common method of fixation for these injuries, but refracture continues to be a problem. Various other fixation strategies, such as headless compression screws, plantar plating, and tension-band wiring. have been developed to mitigate these issues. Biomechanical studies with regard to these other fixation strategies are limited. Herein, we investigate the compression strength and angular stiffness of Jones fractures fixed with Herbert-style headless compression screws. Methods. Jones fractures were created in 10 fresh-frozen pairs of cadaveric fifth metatarsals. A bone from each pair was instrumented with either a conventional, partially threaded screw 5.0 or 6.5 mm in diameter, or a headless compression screw 5.0 or 7.0 mm in diameter. Sizes were determined via sequential tapping until a snug fit was obtained. Each metatarsal was stressed via cantilever bending over 1000 cycles. We monitored compression and displacement throughout. Results. Headless compression screws achieved a significantly higher amount of stiffness than conventional, partially threaded screws (P = 0.005). There was no statistically significant difference with respect to compression. Conclusion. In a cadaveric model, headless compression screws achieved a greater amount of fracture stiffness versus conventional, partially threaded screws. Levels of Evidence: Therapeutic, Level V: Biomechanical

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Arthroscopic treatment of refractory adhesive capsulitis of the shoulder

Revista do Colégio Brasileiro de Cirurgiões ◽

10.1590/s0100-69912014000100007 ◽

2014 ◽

Vol 41 (1) ◽

pp. 30-35 ◽

Cited By ~ 2

Author(s):

Marcos Rassi Fernandes

Keyword(s):

Conservative Treatment ◽

Range Of Motion ◽

External Rotation ◽

Constant Score ◽

Adhesive Capsulitis ◽

Arthroscopic Surgery ◽

Arthroscopic Treatment ◽

Left Shoulder ◽

Significant Difference

OBJECTIVE: to evaluate the results of arthroscopic treatment of refractory adhesive capsulitis of the shoulder associated as for improved range of motion after a minimum follow up of six years. METHODS: from August 2002 to December 2004, ten patients with adhesive capsulitis of the shoulder resistant to conservative treatment underwent arthroscopic surgery. One interscalene catheter was placed for postoperative analgesia before the procedure. All were in Phase II, with a minimum follow up of two years. The mean age was 52.9 years (39-66), predominantly female (90%), six on the left shoulder. The time between onset of symptoms and surgical treatment ranged from six to 20 months. Four adhesive capsulitis were found to be primary (40%) and six secondary (60%). RESULTS: the preoperative mean of active anterior elevation was 92°, of external rotation was 10.5° of the L5 level internal rotation; the postoperative ones were 149°, 40° and T12 level, respectively. Therefore, the average gain was 57° for the anterior elevation, 29.5° for external rotation in six spinous processes. There was a significant difference in movements' gains between the pre and post-operative periods (p<0.001). By the Constant Score (range of motion), there was an increase of 13.8 (average pre) to 32 points (average post). CONCLUSION: the arthroscopic treatment proved effective in refractory adhesive capsulitis of the shoulder resistant to conservative treatment, improving the range of joint movements of patients evaluated after a minimum follow up of six years.

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Biomechanical Evaluation of Suture Configurations in Lesser Toe Plantar Plate Repairs

Foot & Ankle International ◽

10.1177/1071100718758258 ◽

2018 ◽

Vol 39 (7) ◽

pp. 836-842 ◽

Cited By ~ 2

Author(s):

Fred T. Finney ◽

Simon Lee ◽

Jaron Scott ◽

Todd A. Irwin ◽

James R. Holmes ◽

...

Keyword(s):

Proximal Phalanx ◽

Peak Load ◽

Biomechanical Properties ◽

Biomechanical Analysis ◽

Plantar Plate ◽

Significant Difference ◽

Load To Failure ◽

Fresh Frozen ◽

Human Cadavers ◽

Number Of Cycles

Background: Lesser toe metatarsal-phalangeal (MTP) joint instability can be a major source of pain and dysfunction. Instability occurs when there is incompetence of the plantar plate and/or collateral ligaments. Newer operative treatments focus on performing anatomic repairs of the plantar plate. The goal of this study was to compare the biomechanical properties of 3 suture configurations that may be used for plantar plate repairs. Methods: Biomechanical analysis of 27 lesser toe plantar plates from fresh frozen human cadavers was completed. The plantar plate was detached from the proximal phalanx, and suture was placed in the distal plantar plate in a horizontal mattress, luggage-tag, or Mason-Allen suture configuration. Cyclic loading followed by load-to-failure testing was performed. Results: There was a significant difference in peak load-to-failure force between constructs (mattress: 115.53 ± 15.95 N; luggage-tag 102.42 ± 19.33 N; Mason-Allen: 89.96 ± 15.78 N; P = .015). Post hoc analysis demonstrated that the mattress configuration had significantly higher load-to-failure force compared with the Mason-Allen configuration ( P = .004). There were no significant differences between the mattress and the luggage-tag configurations or the luggage-tag and the Mason-Allen configurations. There were no differences in construct stiffness, axial displacement at the time of failure, or number of cycles required to produce 2 mm of displacement. Conclusion: The mattress configuration demonstrated better peak load-to-failure force compared with the Mason-Allen configuration but was not statistically different from the luggage-tag configuration. Although not significant, the mattress configuration trended toward higher load-to-failure force compared with the luggage-tag. Clinical Relevance: The horizontal mattress stitch may be the biomechanically superior configuration in plantar plate repairs.

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A Biomechanical Comparison of Locking and Nonlocking Plates for the Fixation of Calcaneal Fractures

Foot & Ankle International ◽

10.1177/107110070602700308 ◽

2006 ◽

Vol 27 (3) ◽

pp. 196-201 ◽

Cited By ~ 56

Author(s):

David J. Redfern ◽

Miguel L.R. Oliveira ◽

John T. Campbell ◽

Stephen M. Belkoff

Keyword(s):

Locking Plate ◽

Plate Fixation ◽

Testing Machine ◽

Three Dimensional ◽

Materials Testing ◽

Mineral Density ◽

Calcaneal Fractures ◽

Significant Difference ◽

Fresh Frozen ◽

Analysis System

Background: Locking plate systems have been developed in an attempt to increase the strength of fracture fixation and, in so doing, allow earlier mobilization and rehabilitation. The purpose of our study was to compare the mechanical integrity of the locking plate and traditional nonlocking plate fixation for calcaneal fractures in a cadaver model. Our hypothesis was that the locking plate construct provides stronger fixation than the nonlocking plate construct. Methods: We created a Sanders type-IIB fracture in 10 pairs of fresh-frozen cadaver feet (bone mineral density, 0.50 ± 0.14 g/cm2 age, 69 ± 16 years). One foot of each pair was fixed with a nonlocking calcaneal plate (Synthes, Paoli, PA), and the contralateral foot was fixed with the Locking Calcaneal Plate (Synthes, Paoli, PA). The specimens then were cyclically loaded through the tibia from 0 to 700 N at 1 Hz on a materials testing machine to simulate weightbearing. Fragment displacement was measured with a three-dimensional kinematic analysis system. Significance was set at p >0.05. Results: There was no significant difference between the two plating systems with respect to the mean (± SD) number of cycles to failure (locking plate, 3261 ± 2355; nonlocking plate, 2271 ± 2465). Conclusion: In a cadaver model of type-IIB calcaneal fractures, locking plate fixation did not provide a biomechanical advantage over traditional nonlocking plate fixation.

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Nerve graft versus nerve transfer for neonatal brachial plexus: shoulder outcomes

Journal of Neurosurgery Pediatrics ◽

10.3171/2020.6.peds2027 ◽

2021 ◽

Vol 27 (1) ◽

pp. 87-92

Author(s):

Brandon W. Smith ◽

Kate W. C. Chang ◽

Sravanthi Koduri ◽

Lynda J. S. Yang

Keyword(s):

Brachial Plexus ◽

Clinical Data ◽

External Rotation ◽

Nerve Transfer ◽

Shoulder Function ◽

Nerve Transfers ◽

Shoulder Flexion ◽

Significant Difference ◽

Transfer Strategies ◽

Shoulder External Rotation

OBJECTIVEThe decision-making in neonatal brachial plexus palsy (NBPP) treatment continues to have many areas in need of clarification. Graft repair was the gold standard until the introduction of nerve transfer strategies. Currently, there is conflicting evidence regarding outcomes in patients with nerve grafts versus nerve transfers in relation to shoulder function. The objective of this study was to further define the outcomes for reconstruction strategies in NBPP with a specific focus on the shoulder.METHODSA cohort of patients with NBPP and surgical repairs from a single center were reviewed. Demographic and standard clinical data, including imaging and electrodiagnostics, were gathered from a clinical database. Clinical data from physical therapy evaluations, including active and passive range of motion, were examined. Statistical analysis was performed on the available data.RESULTSForty-five patients met the inclusion criteria for this study, 19 with graft repair and 26 with nerve transfers. There were no significant differences in demographics between the two groups. Understandably, there were no patients in the nerve grafting group with preganglionic lesions, resulting in a difference in lesion type between the cohorts. There were no differences in preoperative shoulder function between the cohorts. Both groups reached statistically significant improvements in shoulder flexion and shoulder abduction. The nerve transfer group experienced a significant improvement in shoulder external rotation, from −78° to −28° (p = 0.0001), whereas a significant difference was not reached in the graft group. When compared between groups, there appeared to be a trend favoring nerve transfer in shoulder external rotation, with the graft patients improving by 17° and the transfer patients improving by 49° (p = 0.07).CONCLUSIONSIn NBPP, patients with shoulder weakness experience statistically significant improvements in shoulder flexion and abduction after graft repair or nerve transfer, and patients with nerve transfers additionally experience significant improvement in external rotation. With regard to shoulder external rotation, there appear to be some data supporting the use of nerve transfers.

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The Influence of Force Direction on the Fracture Pattern and Fracture Resistance of Canine Teeth in Dogs

Journal of Veterinary Dentistry ◽

10.1177/0898756417705229 ◽

2017 ◽

Vol 34 (1) ◽

pp. 8-17 ◽

Cited By ~ 2

Author(s):

Stephanie Goldschmidt ◽

Catherine Zimmerman ◽

Caitlyn Collins ◽

Scott Hetzel ◽

Heidi-Lynn Ploeg ◽

...

Keyword(s):

Fracture Resistance ◽

Ex Vivo ◽

Testing Machine ◽

Fracture Pattern ◽

Hard Tissue ◽

Canine Tooth ◽

Cross Sectional ◽

Significant Difference ◽

Force Direction ◽

Testing Group

Biomechanical studies of the elongated canine tooth of animals are few, and thus our understanding of mechanical and physical properties of animal teeth is limited. The objective of the present study was to evaluate the influence of force direction on fracture resistance and fracture pattern of canine teeth in an ex vivo dog cadaver model. Forty-five extracted canine teeth from laboratory beagle dogs were standardized by hard tissue volume and randomly distributed among 3 force direction groups. The teeth were secured within a universal testing machine and a load was applied at different directions based on testing group. The maximum force to fracture and the fracture pattern classification were recorded for each tooth. After correcting for hard tissue cross-sectional area in a multivariate analysis, no significant difference in the amount of force required for fracture was apparent between the different force direction groups. However, the influence of force direction on fracture pattern was significant. The results of this study may allow the clinician to educate clients on possible causal force directions in clinically fractured teeth and, thus, help prevent any contributing behavior in the future.

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Influence of Femoral Version on the Outcomes of Hip Arthroscopic Surgery for Femoroacetabular Impingement or Labral Tears: A Systematic Review and Meta-analysis

Orthopaedic Journal of Sports Medicine ◽

10.1177/23259671211009192 ◽

2021 ◽

Vol 9 (6) ◽

pp. 232596712110091

Author(s):

Chenghui Wang ◽

Yaying Sun ◽

Zheci Ding ◽

Jinrong Lin ◽

Zhiwen Luo ◽

...

Keyword(s):

Systematic Review ◽

Patient Satisfaction ◽

Femoroacetabular Impingement ◽

Arthroscopic Surgery ◽

Harris Hip Score ◽

Cochrane Library ◽

Femoral Version ◽

Labral Tears ◽

Significant Difference ◽

Secondary Outcomes

Background: It remains controversial whether abnormal femoral version (FV) affects the outcomes of hip arthroscopic surgery for femoroacetabular impingement (FAI) or labral tears. Purpose: To review the outcomes of hip arthroscopic surgery for FAI or labral tears in patients with normal versus abnormal FV. Study Design: Systematic review; Level of evidence, 4. Methods: Embase, PubMed, and the Cochrane Library were searched in July 2020 for studies reporting the outcomes after primary hip arthroscopic surgery for FAI or labral tears in patients with femoral retroversion (<5°), femoral anteversion (>20°), or normal FV (5°-20°). The primary outcome was the modified Harris Hip Score (mHHS), and secondary outcomes were the visual analog scale (VAS) for pain, Hip Outcome Score–Sport-Specific Subscale (HOS-SSS), Non-Arthritic Hip Score (NAHS), failure rate, and patient satisfaction. The difference in preoperative and postoperative scores (Δ) was also calculated when applicable. Results: Included in this review were 5 studies with 822 patients who underwent hip arthroscopic surgery for FAI or labral tears; there were 166 patients with retroversion, 512 patients with normal version, and 144 patients with anteversion. Patients with retroversion and normal version had similar postoperative mHHS scores (mean difference [MD], 2.42 [95% confidence interval (CI), –3.42 to 8.26]; P = .42) and ΔmHHS scores (MD, –0.70 [96% CI, –8.56 to 7.15]; P = .86). Likewise, the patients with anteversion and normal version had similar postoperative mHHS scores (MD, –3.09 [95% CI, –7.66 to 1.48]; P = .18) and ΔmHHS scores (MD, –1.92 [95% CI, –6.18 to 2.34]; P = .38). Regarding secondary outcomes, patients with retroversion and anteversion had similar ΔNAHS scores, ΔHOS-SSS scores, ΔVAS scores, patient satisfaction, and failure rates to those with normal version, although a significant difference was found between the patients with retroversion and normal version regarding postoperative NAHS scores (MD, 5.96 [95% CI, 1.66-10.26]; P = .007) and postoperative HOS-SSS scores (MD, 7.32 [95% CI, 0.19-14.44]; P = .04). Conclusion: The results of this review indicated that abnormal FV did not significantly influence outcomes after hip arthroscopic surgery for FAI or labral tears.

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An MRI-Based Patient-Specific Computational Framework for the Calculation of Range of Motion of Total Hip Replacements

Applied Sciences ◽

10.3390/app11062852 ◽

2021 ◽

Vol 11 (6) ◽

pp. 2852

Author(s):

Maeruan Kebbach ◽

Christian Schulze ◽

Christian Meyenburg ◽

Daniel Kluess ◽

Mevluet Sungu ◽

...

Keyword(s):

Range Of Motion ◽

Internal Rotation ◽

Computer Aided Design ◽

External Rotation ◽

Patient Specific ◽

Computational Framework ◽

Total Hip ◽

Total Hip Replacements ◽

Significant Difference ◽

Hip Replacements

The calculation of range of motion (ROM) is a key factor during preoperative planning of total hip replacements (THR), to reduce the risk of impingement and dislocation of the artificial hip joint. To support the preoperative assessment of THR, a magnetic resonance imaging (MRI)-based computational framework was generated; this enabled the estimation of patient-specific ROM and type of impingement (bone-to-bone, implant-to-bone, and implant-to-implant) postoperatively, using a three-dimensional computer-aided design (CAD) to visualize typical clinical joint movements. Hence, patient-specific CAD models from 19 patients were generated from MRI scans and a conventional total hip system (Bicontact® hip stem and Plasmacup® SC acetabular cup with a ceramic-on-ceramic bearing) was implanted virtually. As a verification of the framework, the ROM was compared between preoperatively planned and the postoperatively reconstructed situations; this was derived based on postoperative radiographs (n = 6 patients) during different clinically relevant movements. The data analysis revealed there was no significant difference between preoperatively planned and postoperatively reconstructed ROM (∆ROM) of maximum flexion (∆ROM = 0°, p = 0.854) and internal rotation (∆ROM = 1.8°, p = 0.917). Contrarily, minor differences were observed for the ROM during maximum external rotation (∆ROM = 9°, p = 0.046). Impingement, of all three types, was in good agreement with the preoperatively planned and postoperatively reconstructed scenarios during all movements. The calculated ROM reached physiological levels during flexion and internal rotation movement; however, it exceeded physiological levels during external rotation. Patients, where implant-to-implant impingement was detected, reached higher ROMs than patients with bone-to-bone impingement. The proposed framework provides the capability to predict postoperative ROM of THRs.

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