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1.
Clin Biomech (Bristol, Avon) ; 74: 111-117, 2020 04.
Article in English | MEDLINE | ID: mdl-32171152

ABSTRACT

BACKGROUND: Medial patellofemoral ligament reconstruction and tibial tuberosity anteromedialization are common treatment options for recurrent lateral patellar instability, although ligament reconstruction is not commonly applied to knees with lateral malalignment. METHODS: Multibody dynamic simulation was used to assess knee function following tibial tuberosity anteromedialization and medial patellofemoral ligament reconstruction for knees with lateral malalignment. Dual limb squatting was simulated with six models representing knees being treated for patellar instability with an elevated tibial tuberosity to trochlear groove distance. The patellar tendon attachment on the tibia was shifted medially (10 mm) and anteriorly (5 mm) to represent tibial tuberosity anteromedialization. A hamstrings tendon graft was represented for medial patellofemoral ligament reconstruction. Patellar tracking was quantified based on bisect offset index. The patellofemoral contact pressure distribution was quantified using discrete element analysis. Data were analyzed with repeated measures comparisons with post-hoc tests. FINDINGS: Both procedures significantly reduced bisect offset index, primarily at low flexion angles. The decrease was larger for tibial tuberosity anteromedialization, peaking at 0.18. Tibial tuberosity anteromedialization shifted contact pressures medially, significantly increasing the maximum medial contact pressure at multiple flexion angles, with the maximum pressure increasing up to 1 MPa. INTERPRETATION: The results indicate tibial tuberosity anteromedialization decreases lateral patellar maltracking more effectively than medial patellofemoral ligament reconstruction, but shifts contact pressure medially. Tibial tuberosity anteromedialization is likely to reduce the risk of post-operative instability compared to medial patellofemoral ligament reconstruction. The medial shift in the pressure distribution should be considered for knees with medial cartilage lesions, however.


Subject(s)
Bone Neoplasms/complications , Computer Simulation , Joint Instability/surgery , Ligaments, Articular/surgery , Patellofemoral Joint/surgery , Plastic Surgery Procedures , Tibia/surgery , Biomechanical Phenomena , Female , Humans , Joint Instability/complications , Joint Instability/physiopathology , Ligaments, Articular/physiopathology , Male , Patellofemoral Joint/physiopathology
2.
Knee ; 26(6): 1234-1242, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31786000

ABSTRACT

BACKGROUND: The study focuses on the influence of trochlear dysplasia on patellar tracking related to patellar instability. METHODS: Knee extension against gravity and dual-limb squatting were simulated with seven models representing knees being treated for recurrent instability. Trochlear depth was altered to represent lateral trochlear inclination (LTI) values of 6°, 12° and 24°. Repeated measures analyses compared patellar lateral shift (bisect offset index) across different LTI values. Peak bisect offset index during extension and squatting was correlated with patella alta (Caton-Deschamps index) and maximum lateral position of the tibial tuberosity. RESULTS: Bisect offset index varied significantly (p < 0.05) between different LTI values at multiple flexion angles throughout simulated knee extension and squatting. Average bisect offset values were 1.02, 0.95, and 0.86 for LTI = 6°, 12°, and 24°, respectively, at 0° of flexion for knee extension. The strongest correlation occurred between peak bisect offset index and lateral position of the tibial tuberosity for knee squatting with LTI = 6° (r2 = 0.81, p = 0.006). The strength of the correlation decreased as LTI increased. Caton-Deschamps was only significantly correlated with patellar tracking for LTI = 24° during knee squatting. CONCLUSIONS: A shallow trochlear groove increases lateral patellar maltracking. A lateral tibial tuberosity in combination with trochlear dysplasia increases lateral patellar tracking and the risk of patellar instability. Patella alta has relatively little influence on patellar tracking in combination with trochlear dysplasia due to the limited articular constraint provided by the trochlear groove.


Subject(s)
Joint Instability/etiology , Patella/physiopathology , Patellar Dislocation/etiology , Range of Motion, Articular/physiology , Adolescent , Child , Female , Humans , Knee Joint , Male , Patient-Specific Modeling , Tibia , Young Adult
3.
Orthop Clin North Am ; 49(4): 465-476, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30224008

ABSTRACT

The entire operating room team is responsible for the safety of children in the operating room. As a leader in the operating room, the surgeon is impactful in ensuring that all team members are committed to providing this safe environment. This is achieved by the use of perioperative huddles or briefings, the use of appropriate surgical checklists, operating room standardization, surgeons proficient in the care they provide, and team members that embrace Just Culture.


Subject(s)
Checklist , Operating Rooms/organization & administration , Patient Care Team/standards , Child , Humans , Perioperative Period
4.
J Orthop Res ; 36(12): 3231-3238, 2018 12.
Article in English | MEDLINE | ID: mdl-30024053

ABSTRACT

The study utilizes dynamic simulation of knee function to determine how tibial tuberosity medialization and anteromedialization influence patellar tracking and contact pressures for knees with patellar instability. Dual limb squatting was simulated with six multibody dynamic simulation models representing knees being treated for patellar instability. Each knee exhibited lateral patellar maltracking in the pre-operative condition based on the bisect offset index. The patellar tendon attachment points on the tibia were medialized by 10 mm to represent tibial tuberosity medialization, with an additional 5 mm of anteriorization applied for anteromedialization. The patellofemoral contact pressure distribution was quantified using discrete element analysis. Data were analyzed with repeated measures analysis of variance with post-hoc tests and linear regressions. Tibial tuberosity medialization and anteromedialization significantly (p < 0.05) decreased the bisect offset index for nearly all flexion angles up to 80°, with the largest changes near full extension. Both procedures significantly decreased the maximum lateral pressure at 55°, but increased the maximum medial pressure from 30 to 80°. The pre-operative to post-operative increase in the maximum contact pressure was significantly correlated with the maximum pre-operative bisect offset index for tuberosity medialization (r2 = 0.84), but not for anteromedialization. Statement of Clinical Significance: The results indicate tibial tuberosity medialization decreases patellar lateral maltracking and lateral patellofemoral contact pressures, but increases medial contact pressures. When pre-operative patellar maltracking is relatively low, tibial tuberosity medialization is likely to increase maximum contact pressures. Tibial tuberosity anteromedialization lowers the risk of elevated post-operative contact pressures compared to medialization. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3231-3238, 2018.


Subject(s)
Computer Simulation , Joint Instability/surgery , Patella/surgery , Tibia/surgery , Adolescent , Adult , Biomechanical Phenomena , Female , Humans , Joint Instability/physiopathology , Male , Young Adult
5.
Knee ; 25(2): 262-270, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29544985

ABSTRACT

BACKGROUND: Continued patellar instability can occur following medial patellofemoral ligament (MPFL) reconstruction. Computational simulation of function was used to investigate the influence of the lateral position of the tibial tuberosity, trochlear dysplasia and patella alta on lateral patellar tracking following MPFL reconstruction. METHODS: Multibody dynamic simulation models were developed to represent nine knees being treated for recurrent patellar instability. Knee extension against gravity and dual limb squatting were simulated with and without simulated MPFL reconstruction. Graft resting lengths were set to allow 10mm and five millimeters of patellar lateral translation at 30° of knee flexion. The bisect offset index, lateral tibial tuberosity to posterior cruciate ligament tibial attachment (TT-PCL) distance, lateral trochlear inclination, and Caton-Deschamps index were quantified at every five degrees of knee flexion to characterize lateral tracking, lateral position of the tibial tuberosity, trochlear dysplasia, and patella alta, respectively. For the pre-operative and post-operative conditions and each type of motion, bisect offset index was correlated with the anatomical parameters using stepwise multivariate linear regression. RESULTS: For both motions, the pre-operative and post-operative bisect offset indices were significantly correlated with lateral trochlear inclination and lateral TT-PCL distance. For both motions, the adjusted r2 decreased with MPFL reconstruction, but was still approximately 0.5 for MPFL reconstruction allowing five millimeters of lateral translation. CONCLUSION: MPFL reconstruction decreases but does not eliminate lateral maltracking related to trochlear dysplasia and a lateralized tibial tuberosity. Patients with these pathologies are likely at the highest risk for instability related to maltracking following MPFL reconstruction.


Subject(s)
Computer Simulation , Joint Instability/physiopathology , Ligaments, Articular/surgery , Patellofemoral Joint/surgery , Postoperative Complications/physiopathology , Adolescent , Child , Female , Humans , Imaging, Three-Dimensional , Joint Instability/diagnostic imaging , Ligaments, Articular/diagnostic imaging , Ligaments, Articular/physiopathology , Magnetic Resonance Imaging , Patellofemoral Joint/diagnostic imaging , Patellofemoral Joint/physiopathology , Recurrence , Young Adult
6.
J Knee Surg ; 31(6): 557-561, 2018 Jul.
Article in English | MEDLINE | ID: mdl-28743141

ABSTRACT

Tibial rotations with respect to the femur influence measurements used to assess the lateral position of the tibial tuberosity. This study utilized computational modeling to quantify how the tibial tuberosity to trochlear groove (TT-TG) and tibial tuberosity to posterior cruciate ligament attachment (TT-PCL) distances vary with tibial internal/external and varus/valgus rotations. Computational models were developed from magnetic resonance imaging data to represent eight knees with patellar instability. TT-TG and TT-PCL distances were quantified from the computational models for a neutral orientation and with the tibia rotated internally and externally and into varus and valgus in 1-degree increments to 5 degrees. Regression analyses related tibial rotations to TT-TG and TT-PCL distances. TT-TG distance increased with tibial external rotation, and both TT-TG and TT-PCL distances increased with valgus orientation (r2 > 0.94 for all regressions). The average increase in TT-TG distance for each 1 degree of tibial external rotation was 0.55 mm (range: 0.50-0.62 mm), compared with 0.00 mm (range: -0.05 to 0.04 mm) for TT-PCL distance. The average increase in TT-TG distance for each 1 degree of valgus was 1.01 mm (range: 0.91-1.14 mm), compared with 0.46 mm (range: 0.32-0.60 mm) for TT-PCL distance. TT-TG distance varies more with tibial rotations than TT-PCL distance due to both points being on the tibia and a smaller proximal-distal distance between the points for TT-PCL distance.


Subject(s)
Computer Simulation , Femur/diagnostic imaging , Joint Instability/diagnostic imaging , Patellofemoral Joint/diagnostic imaging , Posterior Cruciate Ligament/diagnostic imaging , Tibia/diagnostic imaging , Adult , Algorithms , Female , Humans , Knee Joint/diagnostic imaging , Magnetic Resonance Imaging , Male , Rotation
7.
Knee Surg Sports Traumatol Arthrosc ; 26(10): 2883-2890, 2018 Oct.
Article in English | MEDLINE | ID: mdl-29128875

ABSTRACT

PURPOSE: Graft tensioning during medial patellofemoral ligament (MPFL) reconstruction typically allows for lateral patellar translation within the trochlear groove. Computational simulation was performed to relate the allowed patellar translation to patellofemoral kinematics and contact pressures. METHODS: Multibody dynamic simulation models were developed to represent nine knees with patellar instability. Dual limb squatting was simulated representing the pre-operative condition and simulated MPFL reconstruction. The graft was tensioned to allow 10, 5, and 0 mm of patellar lateral translation at 30° of knee flexion. The patellofemoral contact pressure distribution was quantified using discrete element analysis. RESULTS: For the 5 and 10 mm conditions, patellar lateral shift decreased significantly at 0° and 20°. The 0 mm condition significantly decreased lateral shift for nearly all flexion angles. All graft conditions significantly decreased lateral tilt at 0°, with additional significant decreases for the 5 and 0 mm conditions. The 0 mm condition significantly increased the maximum medial pressure at multiple flexion angles, increasing by 57% at 30°, but did not alter the maximum lateral pressure. CONCLUSIONS: Allowing 5 to 10 mm of patellar lateral translation limits lateral maltracking, thereby decreasing the risk of post-operative recurrent instability. Allowing no patellar translation during graft tensioning reduces maltracking further, but can overconstrain the patella, increasing the pressure applied to medial patellar cartilage already fibrillated or eroded from an instability episode.


Subject(s)
Computer Simulation , Ligaments, Articular/surgery , Patella/physiology , Patellofemoral Joint/surgery , Plastic Surgery Procedures , Range of Motion, Articular , Adolescent , Biomechanical Phenomena , Child , Female , Humans , Joint Instability , Male , Models, Biological , Pressure , Transplants , Young Adult
8.
J Orthop Trauma ; 31(7): e200-e204, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28632657

ABSTRACT

OBJECTIVES: To determine the need for computerized tomography (CT) scans in the assessment of pediatric pelvic fractures. DESIGN: Retrospective Chart Review. SETTING: Level-1 Pediatric Trauma Center. PATIENTS/PARTICIPANTS: Thirty pediatric trauma patients with pelvic fractures who have obtained both a radiograph and CT scan. MAIN OUTCOME MEASUREMENTS: Fleiss Kappa coefficient to compare interreliability. RESULTS: The average age of the patients was 7 years (range 1-13 years). Seventeen were males and 13 were females. The Torode and Zieg classification included 3 type I, 6 type II, 13 type III, and 8 type IV. The Kappa value for interobserver agreement comparing radiographs was 0.453, and for CT was 0.42. Three patients (10%) were treated with a spica cast, and none required surgery for their pelvic fracture. Four patients (11%) demonstrated liver, spleen, or kidney injuries on CT. Out of those 4, 1 had indications for laparotomy and drain placement, 1 died secondary to shock, and 2 were treated conservatively. CONCLUSIONS: The results of this study demonstrated that plain radiographs alone can be used to classify and manage most pediatric fractures, confirming Silber previous findings. Furthermore, we recommend the specific instances of Schreck and Haasz et al in which CT scans should be used, sparing the general pediatric population unnecessary radiation. Such cases include patients with an abnormal abdominal or pelvic examination, complex fracture patterns, displacement greater than 1 cm, femur deformities, hematuria, Glasgow Coma Scale <13, hemodynamic instability, an aspartate aminotransferase > 200 U/L, an Hct < 30%, or an abnormal chest x-ray.


Subject(s)
Fractures, Bone/classification , Fractures, Bone/diagnostic imaging , Pelvic Bones/diagnostic imaging , Pelvic Bones/injuries , Tomography, X-Ray Computed , Adolescent , Child , Child, Preschool , Female , Fractures, Bone/surgery , Humans , Infant , Male , Observer Variation , Reproducibility of Results , Retrospective Studies
9.
J Pediatr Orthop ; 37(1): 59-66, 2017 Jan.
Article in English | MEDLINE | ID: mdl-26523700

ABSTRACT

BACKGROUND: The changing nature of the United States (US) health care system has prompted debate concerning the physician supply. The basic questions are: do we have an adequate number of surgeons to meet current demands and are we training the correct number of surgeons to meet future demands? The purpose of this analysis was to characterize the current pediatric orthopaedic workforce in terms of supply and demand, both present and future. METHODS: Databases were searched (POSNA, SF Match, KID, MGMA) to determine the current pediatric orthopaedic workforce and workforce distribution, as well as pediatric orthopaedic demand. RESULTS: The number of active Pediatric Orthopaedic Society of North America (POSNA) members increased over the past 20 years, from 410 in 1993 to 653 in 2014 (155% increase); however, the density of POSNA members is not equally distributed, but correlates to population density. The number of estimated pediatric discharges, orthopaedic and nonorthopaedic, has remained relatively stable from 6,348,537 in 1997 to 5,850,184 in 2012. Between 2003 and 2013, the number of pediatric orthopaedic fellows graduating from Accreditation Council for Graduate Medical Education and non-Accreditation Council for Graduate Medical Education programs increased from 39 to 50 (29%), with a peak of 67 fellows (71%) in 2009. DISCUSSION: Although predicting the exact need for pediatric orthopaedic surgeons (POS) is impossible because of the complex interplay among macroeconomic, governmental, insurance, and local factors, some trends were identified: the supply of POS has increased, which may offset the expected numbers of experienced surgeons who will be leaving the workforce in the next 10 to 15 years; macroeconomic factors influencing demand for physician services, driven by gross domestic product and population growth, are expected to be stable in the near future; expansion of the scope of practice for POS is expected to continue; and further similar assessments are warranted. LEVEL OF EVIDENCE: Level II-economic and decision analysis.


Subject(s)
Orthopedic Surgeons/supply & distribution , Orthopedics , Pediatrics , Fellowships and Scholarships , Health Services Needs and Demand , Humans , North America , Nurse Practitioners/supply & distribution , Orthopedics/education , Pediatrics/education , Physician Assistants/supply & distribution , Societies, Medical , United States , Workforce
10.
Patient Saf Surg ; 9: 8, 2015.
Article in English | MEDLINE | ID: mdl-25705257

ABSTRACT

BACKGROUND: The goal of this project was to implement a daily pre-operative huddle (briefing) for orthopedic cases and evaluate the impact of the daily huddle on surgeons' perceptions of interruptions and operative delays. METHODS: Baseline measurements on interruptions, delays, and questions were obtained. Then the daily pre-operative huddle was introduced. Surgeons completed a surgical outcomes worksheet for each day's cases. Outcomes evaluated were primarily interruptions and delays starting cases before and following introduction of the huddle. RESULTS: 19 baseline observations and 19 huddle-implemented observations of surgeon's days were assessed. Overall, surgeon satisfaction increased and fewer delays occurred after introduction of huddles. Interruptions decreased in all categories including equipment, antibiotics, planned procedure and side. Time required for a huddle was less than one minute per case. CONCLUSIONS: In this pilot study, a daily pre-operative huddle improved the flow of a surgeon's day and satisfaction and indirectly provided indications of safety benefits by decreasing the number of interruptions and delays. Further studies in other surgical specialties should be conducted due to the promising results. Data was collected from three orthopedic surgeons in this phase; however, as a next step, data should be drawn from the rest of the orthopedic surgical team and other surgical subspecialties as well.

11.
J Bone Joint Surg Am ; 97(1): 71-9, 2015 Jan 07.
Article in English | MEDLINE | ID: mdl-25568397

ABSTRACT

BACKGROUND: The incidence of anterior cruciate ligament (ACL) injuries is two to eightfold greater in female compared with male athletes. Anatomic, hormonal, and neuromuscular factors have been associated with this disparity. This study compared gene expression and structural features in ruptured but otherwise normal ACL tissue from young female and male athletes. METHODS: A biopsy sample of ruptured ACL tissue (which would normally have been discarded) was obtained intraoperatively from seven female and seven male athletes (12.7 to 22.6 years old). Each sample was divided into portions for histological and gene expression analyses. Specimens for gene analysis were frozen and ground, and RNA was extracted and purified. Microarray analysis was performed on RNA isolated from four female and three male study participants (13.9 to 18.5 years old) who had a noncontact injury. Genes with an expression level that differed significantly between these female and male athletes were grouped into functionally associated networks with use of IPA software (Qiagen). Three genes of interest were chosen for further validation by RT-qPCR (reverse transcription-quantitative polymerase chain reaction) analysis of the samples from all fourteen patients. Several statistical methods were used to examine sex-related differences. RESULTS: Microarray analysis of the RNA isolated from the ruptured ACL tissue from the female and male athletes identified thirty-two genes with significant differential expression. Fourteen of these genes were not linked to the X or Y chromosome. IPA analysis grouped these genes into pathways involving development and function of skeletal muscle and growth, maintenance, and proliferation of cells. RT-qPCR confirmed significant differences in expression of three selected genes: ACAN (aggrecan) and FMOD (fibromodulin) were upregulated in female compared with male study participants, and WISP2 (WNT1 inducible signaling pathway protein 2) was downregulated. No morphological differences among the ruptured tissue from the various participants were apparent on histological examination. CONCLUSIONS: The genes identified in this study as differing distinctly according to sex produce major molecules in the ACL extracellular matrix. Significant upregulation of ACAN and FMOD (which regulate the matrix) and downregulation of WISP2 (which is involved in collagen turnover and production) may account for the weaker ACLs in female compared with male individuals.


Subject(s)
Anterior Cruciate Ligament/physiopathology , Athletic Injuries/genetics , Knee Injuries/genetics , Adolescent , Anterior Cruciate Ligament/pathology , Anterior Cruciate Ligament/surgery , Anterior Cruciate Ligament Injuries , Anterior Cruciate Ligament Reconstruction , Arthroscopy , Biopsy , Child , Cross-Sectional Studies , Extracellular Matrix/genetics , Female , Gene Expression , Gene Expression Profiling , Humans , Male , Oligonucleotide Array Sequence Analysis , Rupture , Young Adult
12.
Knee Surg Sports Traumatol Arthrosc ; 22(10): 2334-41, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25063490

ABSTRACT

PURPOSE: The current study was performed to relate anatomical parameters to in vivo patellar tracking for pediatric patients with recurrent patellar instability. METHODS: Seven pediatric patients with recurrent patellar instability that failed conservative treatment were evaluated using computational reconstruction of in vivo patellofemoral function. Computational models were created from high-resolution MRI scans of the unloaded knee and lower-resolution scans during isometric knee extension at multiple flexion angles. Shape matching techniques were applied to replace the low-resolution models of the loaded knee with the high-resolution models. Patellar tracking was characterized by the bisect offset index (lateral shift) and lateral tilt. Anatomical parameters were characterized by the inclination of the lateral ridge of the trochlear groove, the tibial tuberosity-trochlear groove distance, the Insall-Salvati index and the Caton-Deschamps index. Stepwise multivariable linear regression analysis was used to relate patellar tracking to the anatomical parameters. RESULTS: The bisect offset index and lateral tilt were significantly correlated with the lateral trochlear inclination (p≤0.002) and TT-TG distance (p<0.05), but not the Insall-Salvati index or the Caton-Deschamps index. For both the bisect offset index and lateral tilt, the standardized beta coefficient, used to identify the best anatomical predictors of tracking, was larger for the lateral trochlear inclination than the TT-TG distance. CONCLUSION: For this population, the strongest predictor of lateral maltracking that could lead to patellar instability was lateral trochlear inclination. LEVEL OF EVIDENCE: Diagnostic study, Level II.


Subject(s)
Joint Instability/physiopathology , Patella/physiopathology , Patellofemoral Joint/physiopathology , Adolescent , Female , Humans , Image Processing, Computer-Assisted , Joint Instability/surgery , Knee Joint , Linear Models , Magnetic Resonance Imaging , Male , Models, Biological , Range of Motion, Articular , Regression Analysis , Tibia/surgery , Young Adult
13.
J Pediatr Orthop ; 33(2): 128-34, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23389565

ABSTRACT

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is usually treated with percutaneous in situ screw fixation to prevent further progression of deformity. The purpose of this investigation is to compare computer navigation (CN) techniques with traditional fluoroscopic (fluoro) techniques for in situ fixation of SCFE. METHODS: This study was an IRB-approved prospective study of 39 hip pinnings in 33 children. CN techniques were used in 22 cases and fluoro in 17. The CN and fluoro groups were statistically similar in terms of grade and acuity of the slip. Children were assigned to the groups based on the intraoperative imaging technique used by the attending on call, with 3 surgeons in each group taking equal amounts of call. The "approach-withdraw" technique was used in all cases. Postoperative limited-cut, reduced-dose computed tomography (CT) scans were obtained to evaluate screw placement. This included blinded analysis for screw penetration of the joint, screw tip-to-apex distance, the distance the screw passed to the center of the physis, and attainment of center-center position. The number of pin passes, intraoperative radiation exposure, and operating room (OR) time were also analyzed. Statistics used included ANOVA, the χ and median tests. RESULTS: Compared with the fluoro group, CN resulted in more accurate screw placement. There was 1 case of joint penetration in the fluoro group not appreciated intraoperatively but detected on postoperative CT. CN also resulted in statistically significant (P < 0.05) reduced screw tip-to-apex distance and distance to the center of the physis. There was no statistically significant difference between the 2 groups in attainment of the center-center position, number of pin passes, or intraoperative radiation exposure. OR time averaged 19 minutes longer in the CN group. There was no case of avascular necrosis or chondrolysis in either of the groups. CONCLUSIONS: Compared with traditional fluoro techniques, CN in situ fixation of SCFE results in more accurate screw placement, comparable number of pin passes and intraoperative radiation exposure, and increased OR time. The cost-benefit ratio of this technology requires careful consideration at each individual institution. LEVEL OF EVIDENCE: II.


Subject(s)
Orthopedic Procedures/methods , Slipped Capital Femoral Epiphyses/surgery , Surgery, Computer-Assisted/methods , Analysis of Variance , Bone Screws , Child , Female , Fluoroscopy/methods , Follow-Up Studies , Humans , Male , Operative Time , Prospective Studies , Radiation Dosage
14.
Proc Inst Mech Eng H ; 226(10): 752-8, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23157076

ABSTRACT

The hamstrings are considered stabilizers of the anterior cruciate ligament-deficient knee; however, anterior cruciate ligament injury primarily influences tibiofemoral kinematics near full extension, where the hamstrings have the least influence on kinematics. Ten knees were tested at multiple flexion angles in vitro to directly compare the influence of anterior cruciate ligament injury and hamstrings activation on tibiofemoral kinematics. Tibiofemoral kinematics were measured for three testing conditions: (1) anterior cruciate ligament intact, with forces applied through the quadriceps muscles (596 N), (2) anterior cruciate ligament cut, with forces applied through the quadriceps, and (3) anterior cruciate ligament cut, with forces applied through the quadriceps and hamstrings (200 N). Based on repeated measures comparisons performed at each flexion angle, cutting the anterior cruciate ligament significantly (p < 0.05) increased tibial anterior translation, medial translation, and internal rotation at 0 degrees and 15 degrees of flexion by approximately 2.5 mm, 1 mm, and 2 degrees, respectively. Internal rotation also increased significantly at 30 degrees. With the anterior cruciate ligament cut, loading the hamstrings significantly decreased anterior translation, medial translation, and internal rotation at 45 degrees, by approximately 2 mm, 2 mm, and 4 degrees, respectively. Loading the hamstrings caused kinematic changes in the opposite direction of the anterior cruciate ligament injury, but the changes occurred at deeper flexion angles than those at which anterior cruciate ligament injury influenced tibiofemoral kinematics.


Subject(s)
Anterior Cruciate Ligament Injuries , Anterior Cruciate Ligament/physiopathology , Knee Injuries/physiopathology , Knee Joint/physiopathology , Muscle Contraction , Muscle, Skeletal/physiopathology , Postural Balance , Aged , Aged, 80 and over , Humans , Male , Middle Aged , Range of Motion, Articular
15.
J Pediatr Orthop ; 32(1): 15-20, 2012.
Article in English | MEDLINE | ID: mdl-22173382

ABSTRACT

BACKGROUND: Anterior cruciate ligament (ACL) injury alters tibiofemoral contact during function, with a posterior shift of the point of contact on the tibia. An all-epiphyseal approach to ACL reconstruction is performed in pediatric patients to improve tibiofemoral contact without disturbing the physis. The hypothesis of the study is that all-epiphyseal ACL reconstruction will shift contact anteriorly on the tibia, as compared with the ACL-deficient knee. METHODS: Ten cadaver knees were tested with the ACL cut and with an all-epiphyseal reconstruction. The knees were set at multiple flexion angles (0, 15, 30, and 45 degrees) and loaded with a quadriceps force of 596 N in combination with an anterior force of 100 N, with the quadriceps loaded in isolation, and with the quadriceps loaded in combination with a hamstrings force of 200 N. Sensors under the menisci characterized the center of force on the tibia. Paired t tests were used to identify significant (P<0.05) differences between the reconstructed and cut conditions for all loading conditions at all flexion angles. RESULTS: On the medial plateau, the average center of force was 2 to 5 mm more anterior for the reconstructed condition than for the ACL cut, with the difference significant for all test conditions. The largest differences between the ACL conditions occurred for the combination of quadriceps forces plus an anterior force. On the lateral plateau, the anterior shift in the center of force from the ACL cut to reconstructed condition was significant for all flexion angles except 0 degree for all loading conditions, with an average difference of approximately 2 mm for all significant differences. CONCLUSIONS: All-epiphyseal ACL reconstruction shifts contact anteriorly on the tibia compared with the injured knee. CLINICAL RELEVANCE: The anterior shift of contact on the femur related to all-epiphyseal ACL reconstruction reduces changes related to ACL injury, which could reduce the risk of cartilage damage and meniscal injuries without violating the growth plate in pediatric patients.


Subject(s)
Anterior Cruciate Ligament Reconstruction/methods , Anterior Cruciate Ligament/surgery , Knee Joint/surgery , Aged , Aged, 80 and over , Anterior Cruciate Ligament Injuries , Cadaver , Epiphyses/surgery , Female , Femur/pathology , Humans , In Vitro Techniques , Knee Joint/pathology , Male , Middle Aged , Tibia/pathology
16.
J Child Orthop ; 3(1): 39-46, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19308611

ABSTRACT

PURPOSE: Residual midfoot and hindfoot deformities in rigidly deformed feet present a very complicated surgical dilemma. A plantigrade foot is desirous for proper lower extremity mechanics in a child with ambulatory potential. In this group of patients, soft tissue procedures are no longer an appropriate option, and well-recognized hindfoot procedures, such as talectomy, have many disadvantages. This study reviews the results obtained using multiplanar supramalleolar osteotomy as a salvage procedure to correct deformities of the complex rigid foot in children. METHODS: A retrospective review was conducted of 27 multiplanar supramalleolar osteotomies in 18 children. The underlying diagnosis of the patients included seven severely rigid idiopathic clubfeet, five arthrogryposis, two myelodysplasia, one Ellis-van Creveld, one Streeter's, one cerebral palsy, and one severe burn contracture. The average age at surgery was 5.6 years, and follow-up averaged 8 years. A successful outcome was deemed a plantigrade foot on physical exam with follow-up of at least 2 years and no subsequent tibial surgeries. All failures were included regardless of the length of follow-up. RESULTS: A plantigrade attitude of the hindfoot was obtainable at the time of surgery in all cases. Eighteen of the 27 feet had a successful outcome. Nine of 27 (33%) feet had recurrence of the foot deformity requiring additional surgery. Time to recurrence averaged 5.7 years (9 months-13 years). Complications from the surgery included four minor wound healing problems, two delayed unions, and one screw recession, all of which healed without consequences. There was no evidence of nonunion, growth plate closure, infection, or fracture above or through screw holes. CONCLUSION: The multiplanar supramalleolar osteotomy appears to be a reasonable salvage procedure for severely scarred and complex rigid foot deformities and can be reinstituted for failures due to remaining growth.

17.
J Pediatr Orthop ; 22(3): 285-9, 2002.
Article in English | MEDLINE | ID: mdl-11961440

ABSTRACT

The senior author (A.G.) has gained extensive experience using freeze-dried cancellous allograft chips to obtain solid posterior fusion in patients with adolescent idiopathic scoliosis. The purpose of this study is to determine whether this form of allograft bone will yield successful fusion rates and maintain a minimal loss of curve correction when combined with current segmental posterior spinal instrumentation systems. Radiographs of 55 patients were evaluated by two masked reviewers using a previously devised grading system. At an average follow-up of 39 months (minimum 24 months), the overall fusion rate was 92.7% and the loss of curve correction was 3.4 degrees. The results of this study show that freeze-dried allograft chips yield successful fusion rates and only minimal loss of curve when combined with current posterior spinal instrumentation systems in patients with pediatric idiopathic scoliosis.


Subject(s)
Bone Transplantation , Scoliosis/surgery , Spinal Fusion , Adolescent , Child , Female , Freeze Drying , Humans , Male , Radiography , Retrospective Studies , Scoliosis/diagnostic imaging , Transplantation, Homologous , Treatment Outcome
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