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1.
Artículo en Inglés | MEDLINE | ID: mdl-38631457

RESUMEN

BACKGROUND: While forward elevation, abduction, and external rotation are often successfully restored, internal rotation (IR) is frequently not satisfactorily recovered following reverse shoulder arthroplasty (RSA), affecting patients' ability to perform certain daily activities. This study examined the prevalence of limited IR in patients receiving modern RSA and its impact on clinical outcomes and patient satisfaction with their RSA. METHODS: A cross-sectional study was conducted on patients who had undergone primary RSA using a modern RSA prosthesis with a minimum one-year follow-up. Patients returned for a research visit where they were examined for range of motion and surveyed for patient-reported outcome measures (PROMs) and subjective rating of the success level of their RSA. Postoperative range of motion data were compared with the preoperative data. The relationship of postoperative IR with PROMs and patients' subjective rating of RSA was analyzed. Logistic regression was performed to identify factors affecting patients' subjective rating of RSA. RESULTS: A total of 78 patients met the criteria and completed the study. A significant portion (59%) reported subjective IR limitations, and 41% showed objective IR limitations. Comparison of preoperative and postoperative IR showed that 24% had worsened IR, while 33% improved. Limited IR was associated with lower patients' subjective rating of RSA and negatively impacted PROMs, especially when the dominant side was operated on. Regression analysis showed that limited IR was the only independent determining factor that was significantly associated with lower subjective rating of RSA. DISCUSSION: Despite advancements in RSA design, limited IR remains a prevalent issue, significantly affecting patients' satisfaction and clinical outcomes. This study underscores the need for setting appropriate expectations regarding IR through patient education and focused efforts to improve IR limitations in RSA patients, particularly on the dominant side.

2.
J Shoulder Elbow Surg ; 33(1): 6-13, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37579940

RESUMEN

BACKGROUND: Cutibacterium acnes remains the most commonly detected organism in shoulder arthroplasty. C acnes infection is thought to occur during shoulder arthroplasty through contamination of the surgical field with C acnes from the incised dermis. The purpose of this study was to examine whether using electrocautery for making skin incisions would decrease C acnes culture rates at the incised dermis compared to using scalpels during shoulder arthroplasty. METHODS: Patients undergoing primary shoulder arthroplasty were randomized into 2 groups, electrocautery vs. scalpel incision group. All patients received a standard preoperative antiseptic preparation including chlorhexidine gluconate showers, intravenous antibiotic administration, and topical application of hydrogen peroxide, povidone iodine, isopropyl alcohol, and DuraPrep. Cultures were obtained from the incised dermal edge immediately after skin incision and later from surgeon's gloves and forceps immediately prior to humeral component implantation. The primary outcome was positive C acnes culture rates compared between the groups. RESULTS: A total of 64 patients (32 in each group) were enrolled. There were 24 males in each group. Regarding dermis cultures, 10 patients (31%) in the scalpel group were positive with 8 of them positive for C acnes, whereas no patients in the electrocautery group were positive (P < .001). Regarding glove cultures, the electrocautery group had 8 patients positive C acnes, while the scalpel group had 8 (P = .777). Regarding forceps cultures, the electrocautery group had 4 patients positive for C acnes, and the scalpel group had 6 (P = .491). All positive cultures were exclusively from male patients. There were no wound complications or infection in the electrocautery group while the scalpel group had 1 acute postoperative infection. CONCLUSIONS: Making skin incisions using electrocautery resulted in 0 C acnes culture at the incised dermis, suggesting its potential effect against C acnes. However, despite this initial antibacterial effect, C acnes still appeared on surgeon's gloves and forceps during surgery of male patients. All positive cultures were from male patients, suggesting that the source of C acnes was specifically related to the male body. While the study hypothesis was supported by the results, the present study also raises new questions and calls for further research.


Asunto(s)
Antiinfecciosos Locales , Artroplastía de Reemplazo de Hombro , Articulación del Hombro , Humanos , Masculino , Artroplastía de Reemplazo de Hombro/efectos adversos , Articulación del Hombro/cirugía , Articulación del Hombro/microbiología , Piel/microbiología , Estudios Prospectivos , Propionibacterium acnes , Antibacterianos/uso terapéutico
3.
Instr Course Lect ; 73: 625-637, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38090929

RESUMEN

Elbow stiffness is a common consequence of trauma and can significantly limit the functionality of the affected arm. Intervention may be necessary for those with a motion arc less than 100°, but the decision to intervene should be based on individual patient needs. Restoration of joint motion in a stiff elbow can be challenging, time consuming, and costly. Nonsurgical treatment is the primary management option, and surgical intervention is considered for refractory stiffness. However, recurrent stiffness is a common issue following surgical elbow contracture release. An overview of relevant elbow anatomy, principles and technical pearls of arthroscopic and open contracture release, and postoperative rehabilitation methods to reduce the risk of recurrent stiffness is provided. It is important to tailor the treatment plan to each patient's unique needs and functional expectations.


Asunto(s)
Contractura , Articulación del Codo , Humanos , Brazo , Artroscopía , Contractura/etiología , Contractura/cirugía , Codo , Articulación del Codo/cirugía , Rango del Movimiento Articular
4.
Arthrosc Tech ; 12(11): e1955-e1961, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-38094971

RESUMEN

Glenoid bone loss in patients with recurrent anterior shoulder instability poses a unique challenge to treating surgeons. Various bone block procedures have been used to reconstruct the glenoid, including autologous coracoid transfer, iliac crest autograft, distal clavicle autograft, and distal tibia allograft. Distal tibia allograft has been increasingly used because of its advantages over autologous graft sources. Having started out as an open procedure, glenoid reconstruction with distal tibia allograft has now found its way to evolving into an arthroscopic procedure. Various techniques have been devised for arthroscopic distal tibia allograft fixation, including screw, suture anchor, and suture button. This technical note describes an arthroscopic distal tibia allograft fixation technique, using a transglenoid parallel drill guide and 2 cerclage tape sutures that are fastened using a tensioner. This technique provides strong graft fixation while avoiding the potential complications and technical challenges of metal screw fixation.

6.
Instr Course Lect ; 72: 211-221, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36534858

RESUMEN

Proximal humerus fractures are common injuries that account for 10% of all fractures in the elderly. Several options are available for the management of proximal humerus fractures. Optimal treatment is based on the fracture pattern and the patient characteristics. Most of these fractures are minimally displaced and managed nonsurgically. Approximately 15% of proximal humerus fractures are comminuted, head-split, fracture-dislocation, or severely displaced, which make the best treatment option more challenging. Hemiarthroplasty is still a viable option in selected patients of these groups; however, advancements in locking plate designs and introduction of reverse total shoulder arthroplasty have led to better clinical outcome in meticulously selected patients. Nonetheless, the debate continues regarding the best management. It is important to discuss the best treatment options based on current literature.


Asunto(s)
Artroplastía de Reemplazo de Hombro , Fracturas Conminutas , Fracturas del Húmero , Fracturas del Hombro , Humanos , Anciano , Artroplastia , Fracturas del Hombro/cirugía , Fracturas Conminutas/cirugía , Fracturas del Húmero/cirugía , Resultado del Tratamiento , Húmero/lesiones , Húmero/cirugía , Fijación Interna de Fracturas
8.
J Bone Joint Surg Am ; 104(19): 1730-1737, 2022 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-35778995

RESUMEN

BACKGROUND: While providing effective analgesia following shoulder arthroplasty, an interscalene block has known complications. Local infiltration analgesia (LIA) using ropivacaine has been successfully employed in other joint arthroplasties, but its efficacy in shoulder arthroplasty has not been studied extensively. The purpose of this study was to compare pain and opioid consumption between LIA and an interscalene block following shoulder arthroplasty. METHODS: Patients undergoing primary shoulder arthroplasty were prospectively randomized into 2 groups: the block group received an interscalene block using liposomal bupivacaine, and the injection group received an LIA injection intraoperatively. The LIA injection included ropivacaine, epinephrine, ketorolac, and normal saline solution. Postoperative visual analog scale pain scores, opioid consumption in morphine milligram equivalents, and complications were compared between the groups. The mean pain scores during the first 24 hours postoperatively were used to test noninferiority of LIA compared with an interscalene block. RESULTS: The study included 74 patients (52 men and 22 women with a mean age of 69 years; 37 were in the injection group and 37 in the block group). There was no significant difference between the groups with respect to pain scores at any postoperative time points (p > 0.05), except for the 8-hour time point, when the injection group had a significantly higher pain score than the block group (p = 0.01). There was no significant difference in opioid consumption between the groups at any time points postoperatively (p > 0.05). The amount of intraoperative opioid consumption was significantly higher in the injection group (p < 0.001). In noninferiority testing for the mean pain scores during the first 24 hours, the injection group was found to be noninferior to the block group. One patient in the block group developed transient phrenic nerve palsy. One patient in the injection group developed dislocation after reverse arthroplasty related to noncompliance. The mean procedure hospital charge was $1,718 for an interscalene block and $157 for LIA. CONCLUSIONS: LIA and an interscalene block provided similar analgesia during the first 24 hours after primary shoulder arthroplasty. LIA was associated with worse pain at 8 hours postoperatively and more intraoperative opioid consumption but was also substantially less costly. LEVEL OF EVIDENCE: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.


Asunto(s)
Analgesia , Artroplastía de Reemplazo de Hombro , Bloqueo del Plexo Braquial , Anciano , Analgesia/métodos , Analgésicos Opioides/uso terapéutico , Anestésicos Locales/uso terapéutico , Artroplastia , Artroplastía de Reemplazo de Hombro/métodos , Bloqueo del Plexo Braquial/métodos , Bupivacaína , Epinefrina/uso terapéutico , Femenino , Humanos , Ketorolaco/uso terapéutico , Masculino , Derivados de la Morfina/uso terapéutico , Manejo del Dolor/métodos , Dimensión del Dolor , Dolor Postoperatorio/tratamiento farmacológico , Estudios Prospectivos , Ropivacaína , Solución Salina/uso terapéutico
9.
J Shoulder Elb Arthroplast ; 6: 24715492221075446, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35669620

RESUMEN

Background: Intraarticular corticosteroid injection is commonly used conservative treatment for glenohumeral osteoarthritis (OA). The purpose of this study was to investigate the clinical fate of symptomatic glenohumeral OA following intraarticular corticosteroid injection and to identify factors associated with undergoing shoulder arthroplasty. Methods: Glenohumeral OA patients who had undergone at least one glenohumeral corticosteroid injection from 2012 to 2017 were identified. Data for demographics, comorbidities, number of injections, severity of radiographic arthritis, and subsequent treatment were collected up to February 2020. Data were analyzed to compare between patients who had eventually undergone shoulder arthroplasty and those who had not. Results: A total of 311 shoulders (275 patients) were followed up for 3 to 8 years after the index injection. The mean age of patients was 64.7 years. There were 148 females, and 116 shoulders (37.3%) eventually underwent arthroplasty, 68 (21.9%) further injections only, 104 (33.4%) no further treatment, 14 (4.5%) a non-arthroplasty surgical procedure, and 9 (2.9%) were lost to follow up. Severity of radiographic arthritic changes, female sex, younger age, and nonsmoking status were found to be significantly associated with undergoing arthroplasty (p < 0.001, p = 0.014, p = 0.003, and p = 0.043, respectively). Conclusion: Approximately one third of glenohumeral OA patients who had received an intraarticular corticosteroid injection eventually elected to undergo shoulder arthroplasty within 3 to 8 years of the injection. High-grade arthritic changes in radiographs, female gender, and younger age were found to be independent factors associated with undergoing arthroplasty. This information may be useful in counseling patients about their future clinical course.Level of Evidence: Level III Retrospective comparative study.

10.
JSES Rev Rep Tech ; 2(2): 149-154, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-37587963

RESUMEN

Background: Lateral scapular radiographs have been routinely included in the initial radiographic examination of both traumatic and nontraumatic shoulder conditions. With the advance of modern imaging modalities, the clinical utility of the lateral scapular view has become questionable. The purpose of the study was to assess the utilization of the lateral scapular view among the members of the American Shoulder and Elbow Surgeons (ASES) and to determine the clinical utility of the lateral scapular view in the initial evaluation of nontraumatic shoulder conditions. Methods: The study consisted of two parts. The first part involved an online survey of ASES members, which asked them 3 questions regarding their preference for radiographic evaluation of new patients with nontraumatic shoulder pain. The second part involved a clinical vignette-based survey, where 4 shoulder surgeons at our institution were given 50 clinical vignettes and asked to independently answer 4 questions regarding the most probable diagnosis, abnormal radiographic findings, further imaging studies, and treatment plan for each case. The survey was repeated twice; the first was given without a lateral scapular view, and the second given 4 weeks later with a lateral scapular view included. We obtained diagnostic accuracy and percent agreement of each surgeon over two surveys and intraobserver and interobserver reliability on each variable. Results: Of a total of 235 ASES members who responded to the online survey, 193 (82.1%) indicated their routine use of a lateral scapular view. The most common reason for obtaining the view was better characterization of acromion morphology (75.4%). The clinical vignette-based survey showed substantial intrarater reliability (κ > 0.6) of the 4 surgeons between the two surveys for the most probable diagnosis, abnormal x-ray findings, and further imaging studies, while the intrarater reliability for treatment plan was moderate (κ = 0.548). The mean diagnostic accuracy of the 4 surgeons was almost equal (74% vs. 75%) between the surveys. Overall, each surgeon's percent agreement across the 2 surveys was over 70%. None of the 4 surgeons recommended a lateral scapular view for further imaging during the first survey; each wanted either advanced imaging (computed tomography, magnetic resonance imaging) or none. Discussion: The addition of a lateral scapular radiograph in the presence of other orthogonal views does not appear to improve surgeons' diagnostic accuracy or affect their decision-making on the treatment plan in nontraumatic shoulder conditions. The clinical utility of the lateral scapular view may need to be reassessed in this setting.

11.
Micromachines (Basel) ; 12(11)2021 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-34832841

RESUMEN

This work presents a polymer-based tactile capacitive sensor capable of measuring joint reaction forces of reverse total shoulder arthroplasty (RTSA). The capacitive sensor contains a polydimethylsiloxane (PDMS) dielectric layer with an array of electrodes. The sensor was designed in such a way that four components of glenohumeral contact forces can be quantified to help ensure proper soft tissue tensioning during the procedure. Fabricated using soft lithography, the sensor has a loading time of approximately 400 ms when a 14.13 kPa load is applied and has a sensitivity of 1.24 × 10-3 pF/kPa at a load of 1649 kPa. A replica RTSA prothesis was 3D printed, and the sensor was mounted inside the humeral cap. Four static right shoulder positions were tested, and the results provided an intuitive graphical description of the pressure distribution across four quadrants of the glenohumeral joint contact surface. It may help clinicians choose a right implant size and offset that best fit a patient's anatomy and reduce postoperative biomechanical complications such as dislocation and stress fracture of the scapula.

12.
Shoulder Elbow ; 13(3): 276-282, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34659467

RESUMEN

BACKGROUND: Arthritic glenoids are susceptible to vault perforation during total shoulder arthroplasty. We investigated the effects of glenoid perforation and subsequent cement extrusion on the suprascapular nerve and on the glenoid cement infiltration. METHODS: Total shoulder arthroplasty using three-pegged glenoid components were performed on 10 cadaveric shoulders assigned to two groups (perforation vs. control). In perforation group, the glenoids were reamed eccentrically and intentionally perforated medially through the central peg hole, whereas control group received perpendicular reaming with no perforation. Bone cement was applied to each peg. Spatial relationship between the extruded cement and the suprascapular nerve, and the amount of cement infiltration into the cancellous bone were evaluated. RESULTS: In perforation group, five specimens were perforated anteriorly, and two posteriorly. In the two posteriorly perforated specimens, the suprascapular nerve was in direct contact with extruded cement at the spinoglenoid notch. Perforation group showed significantly less cement infiltration into the cancellous bone than control group (p = 0.008). CONCLUSIONS: Glenoid perforation decreases the volume of cement infiltration into the cancellous bone potentially compromising glenoid component fixation. Glenoid perforation tends to occur anteriorly rather than posteriorly in arthritic glenoids; however, if perforation occurs posteriorly, the suprascapular nerve is at immediate risk from the extruded cement.Level of evidence: Basic science study.

14.
JBJS Rev ; 9(4)2021 04 22.
Artículo en Inglés | MEDLINE | ID: mdl-33886524

RESUMEN

¼: Radial head arthroplasty is a viable surgical option when a radial head fracture cannot be reconstructed. Radial head arthroplasty provides a load-bearing articular structure against the capitellum in unstable fractured elbows. ¼: Studies have emphasized the importance of choosing the correct implant size to replicate the native radial head anatomy, citing various consequences of improperly sized radial head prostheses. Overstuffing of the radiocapitellar joint, or lengthening of the radius, has been extensively studied because of its detrimental effects on elbow biomechanics, but other types of improper sizing also have negative consequences. ¼: In the setting of severe fracture-dislocation or revision surgery, anatomic landmarks that are useful for prosthesis sizing often are missing. Various methods have been described to provide guidance for the accurate sizing of a prosthetic radial head; a retrieved radial head, the proximal edge of the lesser sigmoid notch, the radiocapitellar synovial fold, and the ulnohumeral joint space all represent useful references. ¼: Intraoperative radiographic examination is an important step while assessing implant size, including the height of the prosthetic radial head. ¼: Since no single method is perfect on its own, the surgeon should combine as many reference measures as possible, both before and during the procedure, for accurate prosthesis sizing in order to achieve successful outcomes.


Asunto(s)
Articulación del Codo , Prótesis de Codo , Fracturas del Radio , Artroplastia , Articulación del Codo/diagnóstico por imagen , Articulación del Codo/cirugía , Humanos , Radio (Anatomía)/diagnóstico por imagen , Radio (Anatomía)/cirugía , Fracturas del Radio/diagnóstico por imagen , Fracturas del Radio/cirugía
15.
JSES Int ; 4(2): 231-237, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32490407

RESUMEN

BACKGROUND: Primary repair of a severely retracted distal biceps tendon can pose a technical challenge. We sought to describe the method and clinical outcomes of a surgical technique used as an adjunct to the conventional anterior single-incision repair for severely retracted biceps tendons. This technique involves a second anterior incision proximally to retrieve a severely retracted tendon followed by passing the tendon through a soft-tissue tunnel. METHODS: We identified 30 consecutive patients who had undergone a primary distal biceps tendon repair by an anterior-approach cortical-button technique. A phone survey was conducted for patient-reported outcomes. Patients returned for bilateral forearm supination strength testing in 2 positions (45º of pronation and 45º of supination). Outcomes were compared between patients who required a second incision and high elbow flexion (>60º) because of severe tendon retraction and those who did not require such interventions. RESULTS: No significant differences in elbow range of motion, supination strength, or patient-reported outcomes were found between the 2 groups of patients (P > .05). Regarding supination strength, the operated side was significantly weaker than the uninjured side in both pronated and supinated positions (P < .05). Both the operated and uninjured sides showed significantly higher torque in a pronated position than in a supinated position (P < .05). CONCLUSIONS: Severely retracted distal biceps tendons can be successfully repaired using a second incision and high elbow flexion without negative effects on the outcomes. Supination strength was decreased following an anterior-approach cortical-button technique, but patient-reported outcomes were not affected negatively.

16.
J Shoulder Elbow Surg ; 27(7): 1297-1305, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29331571

RESUMEN

BACKGROUND: Conventional computed tomography (CT) is not accurate for glenoid version measurement. This study sought to examine the feasibility of an interdepartmental protocol implemented between orthopedic surgery and radiology departments for acquisition of anatomic axial CT images and to validate the glenoid version measured through such a protocol. MATERIALS AND METHODS: Data of 30 conventional CT scans of 10 normal and 20 osteoarthritic glenoids were transferred to clinical 3-dimensional imaging software by a radiology technician trained for the study. The technician independently reoriented the scapulae to generate anatomic CT images. A separate team of orthopedic researchers used laboratory-based 3-dimensional reconstruction software (Mimics; Materialise, Leuven, Belgium) to generate anatomic axial images. Three independent examiners measured glenoid version on the conventional CT, reoriented anatomic CT, and Mimics images at the superior, middle, and inferior levels. Data were analyzed using the Mimics data as the "gold standard." RESULTS: Reoriented anatomic CT images generated by the technician resulted in almost identical version measurements to the Mimics images in both normal and arthritic glenoids. The conventional CT images had poor agreement with the Mimics images in normal glenoids but had good agreement in arthritic glenoids. Both normal and arthritic glenoids had increased retroversion superiorly (P < .05), and this phenomenon was significantly exaggerated on the conventional CT images (P < .05). CONCLUSIONS: This study demonstrated that an interdepartmental protocol can produce reoriented anatomic axial CT images on which true glenoid version can be accurately measured. Such an institutional protocol would help surgeons accurately evaluate glenoid version preoperatively with reduced workload and expense.


Asunto(s)
Artritis/diagnóstico , Cavidad Glenoidea/diagnóstico por imagen , Imagenología Tridimensional , Articulación del Hombro/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Anciano , Protocolos Clínicos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Estudios Retrospectivos , Programas Informáticos , Tomografía Computarizada por Rayos X/métodos
17.
J Shoulder Elbow Surg ; 26(12): 2177-2186, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28869071

RESUMEN

BACKGROUND: Rotator cuff muscle fatty degeneration after a chronic tendon tear is an irreversible pathologic change associated with poor clinical outcomes of tendon repair, and its exact pathogenesis remains unknown. We sought to investigate the role of transplanted bone marrow cells in the development of fatty degeneration, specifically in adipocyte accumulation, using a mouse model. METHODS: Fourteen mice were divided into 2 bone marrow chimeric animal groups: bone marrow transplantation (BMT) group and reverse BMT group. For the BMT group, C57BL/6J wild-type mice underwent whole body irradiation followed by BMT into the retro-orbital sinus from green fluorescent protein (GFP)-transgenic donor mice. For the reverse BMT group, GFP-transgenic mice received BMT from C57BL/6J wild-type donor mice after irradiation. The supraspinatus tendon, infraspinatus tendon, and suprascapular nerve were surgically transected 3 weeks after transplantation. The rotator cuff muscles were harvested 13 weeks after transplantation for histologic analysis and GFP immunohistochemistry. RESULTS: On histologic examination, both groups showed substantial fatty degeneration, fibrosis, and atrophy of the cuff muscles. The BMT group showed no noticeable GFP immunostaining, whereas the reverse BMT group showed significantly stronger GFP staining in most adipocytes (P < .001). However, both groups also showed that a small number of adipocytes originated from transplanted bone marrow cells. A small number of myocytes showed a large cytoplasmic lipid vacuole resembling adipocytes. CONCLUSIONS: This study's findings suggest that most adipocytes in fatty degeneration of the rotator cuff muscles originate from sources other than bone marrow-derived stem cells, and there may be more than 1 source for the adipocytes.


Asunto(s)
Adipocitos/metabolismo , Tejido Adiposo/patología , Células de la Médula Ósea/metabolismo , Trasplante de Médula Ósea , Lesiones del Manguito de los Rotadores/patología , Manguito de los Rotadores/patología , Adipocitos/patología , Animales , Atrofia/patología , Linaje de la Célula , Modelos Animales de Enfermedad , Fibrosis , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Inmunohistoquímica , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Fibras Musculares Esqueléticas/patología , Manguito de los Rotadores/metabolismo , Lesiones del Manguito de los Rotadores/metabolismo
18.
J Biomech ; 53: 78-83, 2017 02 28.
Artículo en Inglés | MEDLINE | ID: mdl-28159312

RESUMEN

A novel technique of "anterior offsetting" of the humeral head component to address posterior instability in total shoulder arthroplasty has been proposed, and its biomechanical benefits have been previously demonstrated experimentally. The present study sought to characterize the changes in joint mechanics associated with anterior offsetting with various amounts of glenoid retroversion using cadaver specimen-specific 3-dimensional finite element models. Specimen-specific computational finite element models were developed through importing digitized locations of six musculotendinous units of the rotator cuff and deltoid muscles based off three cadaveric shoulder specimens implanted with total shoulder arthroplasty in either anatomic or anterior humeral head offset. Additional glenoid retroversion angles (0°, 10°, 20°, and 30°) other than each specimen׳s actual retroversion were modeled. Contact area, contact force, peak pressure, center of pressure, and humeral head displacement were calculated at each offset and retroversion for statistical analysis. Anterior offsetting was associated with significant anterior shift of center of pressure and humeral head displacement upon muscle loading (p<0.05). Although statistically insignificant, anterior offsetting was associated with increased contact area and decreased peak pressure (p > 0.05). All study variables showed significant differences when compared between the 4 different glenoid retroversion angles (p < 0.05) except for total force (p < 0.05). The study finding suggests that the anterior offsetting technique may contribute to joint stability in posteriorly unstable shoulder arthroplasty and may reduce eccentric loading on glenoid components although the long term clinical results are yet to be investigated in future.


Asunto(s)
Artroplastía de Reemplazo de Hombro , Análisis de Elementos Finitos , Cabeza Humeral/cirugía , Fenómenos Mecánicos , Adulto , Fenómenos Biomecánicos , Cadáver , Músculo Deltoides/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Presión , Manguito de los Rotadores/fisiología , Escápula/fisiología , Articulación del Hombro/fisiología , Articulación del Hombro/cirugía
19.
J Shoulder Elbow Surg ; 26(3): 409-415, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27745810

RESUMEN

BACKGROUND: Double-strand lateral ulnar collateral ligament (LUCL) reconstruction is an effective treatment for posterolateral rotatory instability (PLRI) of the elbow, but anatomic landmarks for ulnar tunnel placement are often difficult to identify intraoperatively, which potentially can result in a nonanatomic LUCL reconstruction. This study investigated the effect of ulnar tunnel location on joint stability in double-strand LUCL reconstruction. METHODS: PLRI was artificially created in 7 cadaveric elbows, and double-strand LUCL reconstruction was performed. Five different ulnar tunnels were made along the length of the ulna. In each specimen, each possible pair of 2 tunnels (10 total) were used for graft passage. Varus and posterolateral joint gapping was measured after joint loading using a 3-dimensional digitizer system and X-ray image intensifier. RESULTS: No significant gapping was observed at the posterolateral ulnohumeral joint regardless of the location of the ulnar tunnels (P > .05). In contrast, the lateral radiocapitellar joint showed statistically significant varus gapping when both ulnar tunnels were placed proximal to the radial head-neck junction (P < .05). DISCUSSION: This findings of study suggest that the location of the ulnar tunnels may not be as critical as that of the humeral tunnel during double-strand LUCL reconstruction and that posterolateral rotatory elbow stability can be achieved reasonably well as long as at least 1 of the 2 ulnar tunnels is located at or distal to the radial head-neck junction level.


Asunto(s)
Puntos Anatómicos de Referencia , Ligamento Colateral Cubital/cirugía , Lesiones de Codo , Inestabilidad de la Articulación/cirugía , Adulto , Cadáver , Ligamento Colateral Cubital/lesiones , Articulación del Codo/fisiología , Articulación del Codo/cirugía , Femenino , Humanos , Inestabilidad de la Articulación/etiología , Inestabilidad de la Articulación/fisiopatología , Masculino , Persona de Mediana Edad
20.
J Shoulder Elbow Surg ; 25(11): 1874-1881, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27364146

RESUMEN

BACKGROUND: Selecting a properly sized radial head prosthesis is imperative during radial head replacement. Although there has been much emphasis on avoiding overlengthening of the radius, little has been studied about how to avoid shortening. The purpose of this study was to characterize how a radial head replacement appears on intraoperative fluoroscopy depending on the height of the prosthetic radial head. METHODS: Articular cartilage thickness of the radial head was measured in 9 cadaveric elbows. Radial head replacement was performed in each specimen with 4 different prosthetic head heights: 4 mm and 2 mm shortening, anatomic, and 2 mm overlengthening. Anteroposterior fluoroscopic images were obtained for each head height, and the prosthetic radial head height was measured at 3 forearm positions (supination, neutral, and pronation) using the subchondral bone of the lateral edge of the coronoid at the reference point. RESULTS: The mean cartilage thickness of the radial head was 1.3 ± 0.4 mm. The prosthetic radial head appeared 2.2 ± 0.4 mm more proximal than the subchondral bone of the coronoid lateral edge in anteroposterior radiographs when the articular surface of the prosthesis was completely even with the coronoid articular surface. Unlike the native radial head, a prosthetic radial head showed a significant change of height with different forearm rotation (P < .001). DISCUSSION: This study found that a perfectly anatomic radial head replacement appears overlengthened by approximately 2 mm in intraoperative radiographs. This finding can be useful in guiding the appropriate height of a prosthetic radial head.


Asunto(s)
Artroplastia de Reemplazo de Codo , Prótesis de Codo , Ajuste de Prótesis , Radio (Anatomía)/diagnóstico por imagen , Adulto , Cadáver , Cartílago Articular/anatomía & histología , Cartílago Articular/diagnóstico por imagen , Articulación del Codo/cirugía , Femenino , Fluoroscopía , Humanos , Cuidados Intraoperatorios , Masculino , Persona de Mediana Edad , Radio (Anatomía)/cirugía , Fracturas del Radio/cirugía
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