Lateral versus medial approach for total knee arthroplasty for valgus knee deformity shows comparable functional outcomes, hip-knee-ankle angle values, and complication rates: a meta-analysis of comparative studies.

INTRODUCTION: The aim of this meta-analysis of comparative studies was to update the current evidence on functional and radiographic outcomes and complications between medial and lateral approaches for total knee arthroplasty (TKA) for valgus knee deformity. MATERIALS AND METHODS: The PubMed, MEDLINE, Scopus, and the Cochrane Central databases were used to search keywords and a total of ten studies were included. The methodological quality of the included studies was assessed. Data extracted for quantitative analysis included the Knee Society score (KSS), range of motion (ROM), surgical time, hip-knee-ankle angle (HKA), and number and types of complications. Random- and fixed-effect models were used for the meta-analysis of pooled mean differences (MDs) and odds ratios (ORs). The Mantel-Haenszel method was adopted. RESULTS: A total of 1008 patients were identified, of whom 689 and 319 underwent TKA for valgus knee deformity with lateral and medial approach, respectively. The mean age was 70 ± 9.5 and 67.3 ± 9.6 years for the lateral and medial approaches, respectively. The mean follow-up was 37.8 ± 21.9 and 45.9 ± 26.7 months for the lateral and medial approach groups, respectively. Significantly higher functional outcomes were found for the medial approach, as measured by the postoperative KSS (MD = 1.8, 95% CI [0.48, 3.12], P = 0.007) and flexion ROM (MD = 3.12, 95% CI [0.45, 5.79], P = 0.02). However, both of these differences were lower than the minimal clinically important difference. Comparable surgical time and postoperative HKA angle values (MD = 0.22, 95% CI [- 0.30, 0.75], P = 0.40) between the two surgical approaches were found. The incidence of periprosthetic joint infections, fractures, transient peroneal nerve injuries, and deep vein thrombosis was comparable. CONCLUSION: This meta-analysis of comparative studies showed that when lateral and medial approaches are used for total knee arthroplasty for valgus knee deformity, comparable functional outcomes in terms of the KSS and ROM, surgical time, and postoperative hip-knee-ankle angle values can be expected. Similar rates of periprosthetic joint infection, fracture, and peroneal nerve injury were also found. LEVEL OF EVIDENCE: I. PROSPERO REGISTRATION NUMBER ID: CRD42023392807.

Delaying ACL reconstruction is associated with increased rates of medial meniscal tear.

PURPOSE: The aim of this study was to evaluate the relationship between the time from injury to ACL reconstruction (ACLR) and the rate as well as repairability of meniscal tears. Secondary aims were to evaluate the relationship between meniscal injury and Tegner Activity Scale, age, BMI, and gender. METHODS: Between 2012 and 2022, 1,840 consecutive ACLRs were performed. A total of 1,317 ACLRs were included with a mean patient age of 31.2 years ± 10.5 [16-60]. Meniscal tear was assessed during arthroscopy using the ISAKOS classification. Time from injury to ACLR, Tegner Activity Scale, age, BMI and gender were analysed in uni- and then in multivariate analyses. Patients were divided into four groups according to the time from injury to surgery: < 3 months (427; 32%), 3-6 months (388; 29%), 6-12 months (248; 19%) and > 12 months (254; 19%). RESULTS: Delaying ACLR > 12 months significantly increased the rate of medial meniscal (MM) injury (OR 1.14; p < 0.001). No correlation was found between a 3- or 6-month time from injury to surgery and MM tear. Performing ACLR > 3, 6, or 12 months after injury did not significantly increase the rate of lateral meniscal (LM) injury. Increasing Tegner activity scale was significantly associated with a lower rate of MM injury (OR 0.90; p = 0.020). An age > 30 years (OR 1.07; p = 0.025) and male gender (OR 1.13; p < 0.0001) was also associated with an increased rate of MM injury. Age > 30 years decreased the rate of MM repair (OR 0.85; p < 0.001). Male gender increased the rate of LM tear (OR 1.10; p = 0.001). CONCLUSION: Performing ACLR more than 12 months after injury was associated with increased rates of MM injury but not with lower rates of repairable lesions. An increased pre-injury Tegner activity score was associated with a decreased rate of MM tear. Age > 30 years was associated with an increased rate of MM tear with concomitant ACL injury and a decreased rate of repairability of MM tear. ACLR should be performed within 12 months from injury to prevent from the risk of MM injury. LEVEL OF EVIDENCE: Level III.

Gibson approach and surgical hip dislocation according to Ganz in the treatment of femoral head fractures.

BACKGROUND: The purpose of the study is to evaluate clinical and radiological outcomes in those patients with femoral head fracture, treated with open reduction and internal fixation through Gibson approach and Ganz flip trochanter osteotomy. The treatment of Pipkin fractures is very challenging, especially for small trauma centers, because of the unusual fracture patterns and high-level surgical skills required. CASE PRESENTATION: Between 2017 and 2020, nine cases of Pipkin fractures came to the Emergency Department at the Trauma Center of our Hospital in Rome. Inclusion criteria were the diagnosis of femoral head fracture, the open reduction and internal fixation as surgical choice and at least 24 months follow-up. Patients older than 65 years and those treated through total hip replacement or combined hip procedure (CHP) were excluded. Thus, five patients were included in our case series. The clinical outcome was evaluated according to Western Ontario and McMaster Universities Arthritis Index, Vail Hip score, modified Harris Hip score and Merle D'Aubignè Postel score. Radiographic assessment was scored according to Epstein-Thompson classification and heterotopic ossification was assessed through Brooker classification. The mean follow-up was 24 months (range 12-24). Average modified Harris Hip score was 92.1 points (range 75.9-100), and the average Vail score was 81.8 (range 55-95). WOMAC score was assessed in three different subscales, pain (A), stiffness (B) and physical condition (C), with the following results: 1.4 A (range 0-7), 1.2 B (range 0-6) and 6.4 C (range 0-22). Merle d'Aubignè Postel score resulted excellent for four patients and good for one patient. According to Epstein-Thompson score of the radiological outcome, four patients showed a good result and one a fair result. No mechanical or infective complications occurred in the five patients. CONCLUSIONS: Gibson's approach and surgical hip dislocation through Ganz trochanteric flip osteotomy allow a good exposure of the femoral head and acetabulum, giving us the possibility to perform an anatomical reduction of the fracture. In our case series, satisfactory clinical and radiological short-term results were obtained without significant complications.

Anterior intrapelvic approach and suprapectineal quadrilateral surface plate for acetabular fractures with anterior involvement: a retrospective study of 34 patients.

BACKGROUND: The purpose of the study is to evaluate the use of the suprapectineal quadrilateral surface (QLS) plates associated with the anterior intrapelvic approach (AIP) to the acetabulum in the surgical treatment of acetabular fractures with anterior involvement. METHODS: We did a retrospective study of patients surgically treated with QLS plates and AIP for acetabular fractures with the involvement of the anterior column, between February 2018 and February 2020, in our Hospital. The following data were recorded: mechanism of injury, the pattern of fracture, presence of other associated injuries, the time before performing the surgery, surgical approach, position on operating table, time of surgery, intraoperative bleeding, hospitalization time, intraoperative and postoperative complications. Follow-ups were performed at 1, 3, 6, 12 months, then annually. The clinical-functional outcome was assessed with the Merle d'Aubigne Postel score (MAP) modified by Matta; while the radiological outcome with the Matta Radiological Scoring System (MRSS). A Chi-square test was utilized to examine associations between parametric variables. RESULTS: We included 34 patients, mean age 62.1, with an average follow-up of 20.7 months. The most frequent traumatic mechanism was road trauma. There were 15 isolated anterior columns and 19 associated patterns. There were 5 cases of associated visceral injuries, and 10 cases of other associated skeletal fractures. All patients were in the supine position. The surgical approach used was the AIP in all cases, with the addition of the first window of the ilioinguinal approach in 16 cases and of the Kocher-Langenbeck approach in 2 cases. The average time before performing the surgery was 8.5 days. The mean time of the surgery and the mean length of stay after surgery were 227.9 min and 8.2 days, respectively. There weren't cases of intra-operative complications, while there were postoperative complications in 5 patients. The MRSS was judged anatomical in 26 cases, imperfect in 7 cases and poor in 1 case. The average MAP value was 15.2. We observed a significant relationship between the radiological outcome and the clinical outcome (p < 0.05). CONCLUSIONS: The QLS plates in association with the AIP approach represent an effective treatment strategy for the treatment of acetabular fractures with anterior involvement.

The native coronal orientation of tibial plateaus may limit the indications to perform a kinematic aligned total knee arthroplasty.

PURPOSE: To investigate the coronal alignment of tibial plateaus in normal and osteoarthritic knees and to simulate the effects of a tibial cut performed in total knee arthroplasty (TKA) using a kinematic alignment technique with standard instrumentation. METHODS: The coronal alignment of tibial plateaus was measured in three groups including group 1 (reference group), 50 cadaveric tibiae showing no evidence of degenerative changes of tibial plateaus; group 2, 49 patients who underwent MR of the knee, showing no or mild degenerative changes of the knee joint and, group 3, 54 patients with knee osteoarthritis who underwent computer-assisted total knee arthroplasty. RESULTS: The coronal alignment of tibial plateaus averaged 2.4° with no significant differences between groups. The mean coronal orientation of tibial plateaus was 3° ± 2° in men and 1.6° ± 2° in women (p = 0.03). A coronal alignment of tibial plateaus of 3° or more was found in 69 cases (45%) and 5° or more in 23 (14.7%). The simulation of a tibial cut performed with an error of 3° in varus in 15% of the subjects showing a native coronal orientation of tibial plateaus of 3° or more, led to a final tibial cut greater 6° in 13.7% of cases. CONCLUSIONS: A coronal alignment of tibial plateaus of 3° or more in varus was found in near half of normal subjects and osteoarthritic patients. A preoperative measurement of the coronal alignment of tibial plateaus is advisable in any patients scheduled for kinematic aligned TKA. As errors in the alignment of the tibial component of 3° or more may occur using standard instrumentations, the results of this study raise questions on performing a kinematic aligned TKA with standard instrumentations. LEVEL OF EVIDENCE: IV.

Comparison between posterior sacral plate stabilization versus minimally invasive transiliac-transsacral lag-screw fixation in fractures of sacrum: a single-centre experience.

PURPOSE: The sacrum is a mechanical nucleus working as the base for the spinal column, as well as the keystone of the pelvic ring. Thus, injuries of the sacrum can lead to biomechanical instability and nerve conduction abnormality. METHODS: The common classification is the Denis classification, but these fractures are often part of a lesion of the posterior pelvic ring and therefore the Tile classification is very useful. The goals of operative intervention are to reduce fracture fragments, protect neurological structures, and provide adequate stability for early mobilization. RESULTS: The stabilization of these injuries can be difficult even in a patient with adequate bone stock and concomitant medical comorbidities. The posterior-ring tension-band metallic plate and sacroiliac joint screw are two commonly used methods for posterior internal fixation of the pelvis. CONCLUSIONS: In this study, we evaluate the differences, in the treatment of sacral fractures, between the two techniques, revising the literature and our experience.

Evaluation of the range of motion of scapulothoracic, acromioclavicular and sternoclavicular joints: State of the art.

The scapulothoracic, acromioclavicular and sternoclavicular joints play a fundamental role in the shoulder function. Shoulder complex kinematics have been studied with different methods using: goniometers, 2 static radiographs, 3D motion analyzers (invasive or noninvasive) and digital inclinometers. Goniometers have been used traditionally to assess scapular rotation in relation to the thorax. The intrinsic limit of multiple static two-dimensional shoulder radiographs is the attempt of describing in two what is occurring in three dimensions. Technology innovations have led to the development of the 3D shoulder complex kinematics analysis ETS (Electromagnetic tracking systems) using sensors (invasive bone-pin markers or noninvasive skin surface marker) stitched to the scapula/clavicula, thorax, and humerus. Despite being uncomfortable, invasive 3D motion cortical pins analyzers still represent the current gold standard for tracking shoulder complex kinematics. Therefore, access to three-dimensional biomechanical instrumentations for collecting kinematic data represents an active problem for many physicians. A precise, easy to use and low-cost non-invasive method able to draw and analyze the kinematics of the shoulder complex has not been developed yet. Further researches are necessary to design a new non-invasive method able to draw and analyze the kinematics of the scapula and the whole shoulder complex, precisely.

MENISCAL ALLOGRAFT TRANSPLANTATION COMBINED WITH ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION: A SYSTEMATIC REVIEW.

Introduction: To evaluate the clinical and functional outcomes of meniscal allograft transplantation (MAT) with anterior cruciate ligament reconstruction (ACLR) in a single surgical stage through a systematic review of the currently available evidence. Methods: A systematic search of the PubMed and Google Scholar databases, with no publication date limit, until December 2022 was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Follow-up studies and case series published in English involving patients undergoing a combination of ACLR and MAT were included. The quality of these studies was assessed using the Methodological Index for Non-Randomized Studies (MINORS) checklist. A systematic review of the International Knee Documentation Committee (IKDC), Lysholm and Tegner activity scores was conducted. Results: Seven studies involving 154 patients were included. The mean follow-up was 5,3 years. The mean age at the time of the surgery was of 35.3 years. All studies used the Lysholm Knee score, IKDC score or Tegner activity score to measure clinical outcomes post-operatively and the mean improvements were 26.7, 24.7, and 1.8 respectively. The rate to return to sport was 75.5 %. No intra-operative complications were reported. The post-operative complication rate was 11.6%. Conclusions: MAT combined with ACLR procedure showed good clinical results up to an average of 5 years of follow-up. More studies need to be conducted that can better understand the long-term effects of this combined procedure.

Spring Plates as a Valid Additional Fixation in Comminuted Posterior Wall Acetabular Fractures: A Retrospective Multicenter Study.

BACKGROUND: The posterior wall fracture is the most frequent pattern of acetabular fractures. Many techniques of fixation have been described in the literature and involve plates, screws, or a combination of both. This study aims to investigate the clinical and radiological outcomes of spring plates in the treatment of comminuted posterior wall acetabular fractures. (2) Methods: A retrospective multicenter (four level I trauma centers) observational study was performed. Patients with a comminuted posterior wall acetabular fracture treated with a spring plate (DePuy Synthes, West Chester, PA) were included. Diagnosis was made according to the Judet and Letournel classification. Diagnosis was confirmed with plain radiographs in an antero-posterior view and Judet views, iliac and obturator oblique views, and thin-slice CT with multiplanar reconstructions. (3) Results: Forty-six patients (34 males and 12 females) with a mean age of 51.7 years (range 19-73) were included. The most common mechanism of injury was motor vehicle accident (34 cases). In all cases, spring plates were placed under an overlapping reconstruction plate. The mean follow-up was 33.4 months (range 24-48). The mean period without weight-bearing was 4.9 weeks (range 4-7), and full weight-bearing was allowed at an average of 8.2 weeks (range 7-11) after surgery. (4) Conclusions: According to the present data, spring plates can be considered a viable additional fixation of the posterior wall acetabular fractures.

Return to sport following distal femur osteotomy: a systematic review.

Introduction: Distal femur osteotomies (DFOs) are well-accepted procedures in treating unicompartmental knee osteoarthritis associated with valgus malalignment. This study aims to investigate the Return to sport (RTS) after DFO. Materials and methods: We conducted a systematic review of the literature according to the PRISMA guidelines, including all articles published in English, with no time limit, excluding double-level knee osteotomies. Results: Five articles were included for an overall cohort of 76 patients. The mean follow-up was 45.53 months. The mean age of the patients at the time of surgery was 33.87 years, and the mean malalignment was 5.59° in valgus. In 70 cases, patients received a lateral DFO, while in 6 cases, a medial closing-wedge DFO. An RTS of 86.1% was observed after DFO and a mean time to RTS of 12.3 months. 76.8% of patients recovered to a level equal to or higher than that practiced before the onset of symptoms. No statistically significant differences were observed in the RTS rate between those who performed lateral or medial DFO. Conclusions: RTS after DFO is ubiquitous and occurs around one year after surgery. In most cases, patients report improved performance compared to what they experienced before the onset of symptoms. Unfortunately, while athletes often have RTS at a similar or better level, other patients often see a return to lower impact sports.

Is Cemented Dual-Mobility Cup a Reliable Option in Primary and Revision Total Hip Arthroplasty: A Systematic Review.

Background: Instability is a common complication following total hip arthroplasty (THA). The dual mobility cup (DMC) allows a reduction in the dislocation rate. The goal of this systematic review was to clarify the different uses and outcomes according to the indications of the cemented DMC (C-DMC). Methods: A systematic review was performed using the keywords "Cemented Dual Mobility Cup" or "Cemented Tripolar Cup" without a publication year limit. Of the 465 studies identified, only 56 were eligible for the study. Results: The overall number of C-DMC was 3452 in 3426 patients. The mean follow-up was 45.9 months (range 12-98.4). In most of the cases (74.5%) C-DMC was used in a revision setting. In 57.5% DMC was cemented directly into the bone, in 39.6% into an acetabular reinforcement and in 3.2% into a pre-existing cup. The overall dislocation rate was 2.9%. The most frequent postoperative complications were periprosthetic infections (2%); aseptic loosening (1.1%) and mechanical failure (0.5%). The overall revision rate was 4.4%. The average survival rate of C-DMC at the last follow-up was 93.5%. Conclusions: C-DMC represents an effective treatment option to limit the risk of dislocations and complications for both primary and revision surgery. C-DMC has good clinical outcomes and a low complication rate.

Age over 50 does not predict results in anterior cruciate ligament reconstruction.

Introduction: Grown in the worldwide population of over 50 of age individuals who remain in good health and continue to engage in sports has led to an increase of anterior cruciate ligament (ACL) tears in this aged population. ACL reconstruction was reserved for young and active athletes, but seems to produce good outcomes also in over 50s. Purpose: To compare the patient-reported functional scores, arthrometric outcomes, and complications of primary ACL reconstruction between older (>50 years) and younger (<50 years) patients. Methods: A systematic review was performed on Pubmed, Scopus, Google Scholar and Cochrane library regarding studies that compared the clinical outcomes of ACLR between patients aged > 50 years and those aged < 50 years. The outcomes evaluated were knee functional outcomes, antero-posterior laxity and complications rate. Results: This study included 5 retrospective cohort studies with a total of 645 patients (357 in the older 50 group and 288 in the younger group). All included studies reported significant improvements in clinical outcomes in both groups after ACL reconstruction. No significant differences were noted in terms of International Knee Documentation Committee (IKDC), Lysholm, Tegner scores and anteroposterior instability between the two groups (p = n.s.). Over 50 cohort seem to have an increased risk for complication rate when compared with the younger cohort (p= 0.0005). Conclusion: ACL reconstruction in patients older than 50 years is a safe procedure with good results that are comparable to those of younger patients. Study design: Systematic review and meta-analysis; Level of evidence, 3.

Chronic post-traumatic volar plate avulsions of the finger proximal interphalangeal joint: A literature review of different surgical techniques.

Avulsions of the volar plate of the finger proximal interphalangeal joint (PIPJ) following sprains are often undiagnosed in the acute setting. Therefore, the chronic outcomes of this injury are most frequently the object of study and treatment. Different techniques for volar plate chronic avulsion repair are described in the literature. The most used among these are mainly two: the direct suturing with or without the use of bone anchors and the tenodesis techniques with flexor digitalis superficialis (FDS). The aim of this systematic review is to determine outcomes and complications associated with these surgical treatments of post-traumatic volar plate avulsions without phalangeal fractures. An electronic literature research was carried out and pertinent articles were selected. Surgical techniques details, outcomes and complications for direct sutures and tenodesis technique are discussed. Outcomes (Range of motion and pain) seem to be comparable, whereas authors that use the direct suture technique describe more frequently PIPJ flexion contracture complication. From this review of the literature, authors believe that both techniques are available for the repair of chronic injuries of the volar plate of the PIPJ, although direct suturing can be considered as less reproducible.

Clinical Outcomes and Joint Stability after Lateralized Reverse Total Shoulder Arthroplasty with and without Subscapularis Repair: A Meta-Analysis.

INTRODUCTION: Subscapularis tendon repair in reverse total shoulder arthroplasty represents a potentially modifiable risk factor for dislocation, and its role continues to be debated. The purpose of the present meta-analysis was to compare the outcomes of the primary lateralized RSAs with and without subscapularis repair in terms of range of motion, clinical outcomes, dislocations, and complications rate. MATERIALS AND METHODS: A systematic literature search in MEDLINE (Pubmed), Embase, and the Cochrane Central Register of Controlled Trials database was carried up to December 2020. A data extraction form was developed to collect select data from the included studies. The methodological quality was assessed using a Methodological Index for Nonrandomized Studies (MINORS) score. Statistical analysis was performed with Review Manager (Version 5.4, The Cochrane Collaboration). RESULTS: A total of four comparative studies involving 978 patients were included. In the pooled analysis, the reinsertion of the subscapularis yielded better functional outcomes in terms of the constant (P < 0.00001) and ASES (P = 0.002) scores. The forward elevation, external rotation at 0°, internal rotation, and dislocation rates were comparable between the two groups (P = n.s.), while statistically increased abduction was observed in those patients who did not have their subscapularis repaired (P < 0.00001). CONCLUSION: The results of the present findings suggest that it seems reasonable to reinsert the subscapularis whenever it is present, in good tissue conditions, and with no evidence of fatty degeneration of its muscle belly. LEVEL OF EVIDENCE: Level III meta-analysis.

Navigated percutaneous screw fixation of the pelvis with O-arm 2: two years' experience.

Aim To evaluate the case series of the patients operated with percutaneous fixation by the navigation system based on 3D fluoroscopic images, to assess the precision of a surgical implant and functional outcome of patients. Methods A retrospective study of pelvic ring fractures in a 2-year period included those treated with the use of the O-Arm 2 in combination with the Stealth Station 8. Pelvic fractures were classified according to the Tile and the Young-Burgess classification. All patients were examined before surgery, with X-rays and CT scans, and three days after surgery with additional CT scan. The positioning of the screws was evaluated according to the Smith score, the outcome with the SF-36. Results Among 24 patients 18 were with B and six with C type fracture according to Tile, while eight were with APC, 10 LC, and six with VS type according to Young-Burgess classification. All patients were treated in the supine position, except two. A total of 41 iliosacral or transsacral screws and five anterior pelvic ring screws were implanted. The medium surgical time per screw was 41 minutes. There was a perfect correspondence of screw scores value from post-operative CT and intraoperative fluoroscopy. The mean screw score value was 0.92. There were no cases of poor positioning. The median follow-up was 17.5 months. The patients were satisfied with their health condition on SF-36. Conclusion The use of the O-arm guarantees great precision in the positioning of the screws and reduced surgical times with excellent clinical results in patients.

The stiff elbow: Current concepts.

Elbow stiffness is defined as any loss of movement that is greater than 30° in extension and less than 120° in flexion. Causes of elbow stiffness can be classified as traumatic or atraumatic and as congenital or acquired. Any alteration affecting the stability elements of the elbow can lead to a reduction in the arc of movement. The classification is based on the specific structures involved (Kay's classification), anatomical location (Morrey's classification), or on the degree of severity of rigidity (Vidal's classification). Diagnosis is the result of a combination of medical history, physical examination (evaluating both active and passive movements), and imaging. The loss of soft tissue elasticity could be the result of bleeding, edema, granulation tissue formation, and fibrosis. Preventive measures include immobilization in extension, use of post-surgical drain, elastic compression bandage and continuous passive motion. Conservative treatment is used when elbow stiffness has been present for less than six months and consists of the use of serial casts, static or dynamic splints, CPM, physical therapy, manipulations and functional re-education. If conservative treatment fails or is not indicated, surgery is performed. Extrinsic rigidity cases are usually managed with an open or arthroscopic release, while those that are due to intrinsic causes can be managed with arthroplasties. The elbow is a joint that is particularly prone to developing stiffness due to its anatomical and biomechanical complexity, therefore the treatment of this pathology represents a challenge for the physiotherapist and the surgeon alike.

Symptomatic vertebral hemangioma during pregnancy period: A case series and systematic literature review.

Vertebral Hemangioma (VH) is a benign tumor usually symptomless and discovered incidentally. Pregnancy, because of several hormonal and physiologic changes, is a recognized risk factor coinciding with the development of a rapid onset of neurological symptoms in patients affected by VH. In the Literature, sporadic cases of neurological symptoms have been described, which occurred during pregnancy, but only rarely the onset of symptoms was reported after pregnancy and childbirth. Usually surgical treatment is reserved for severe cases with rapid onset of neurological symptoms. However, the use of conservative treatments is still a topic of debate In the present study, we report a series of patients affected by VH become symptomatic during or after pregnancy along with a systematic review of the Literature.