Comparison of resident performance in interpreting mammography results using a probabilistic or a natural frequency presentation: a multi-institutional randomized experimental study.

BACKGROUND: Residents are being increasingly challenged on how best to integrate diagnostic information in making decisions about patient care. The aim of this study is to assess the ability of residents to accurately integrate statistical data from a screening mammography test in order to estimate breast cancer probability and to investigate whether a simple alteration of the representation mode of probabilities into natural frequencies facilitates these computations. METHODS: A multi-institutional randomized controlled study of residents was performed in eight major hospitals in the city of Athens. Residents were asked to estimate the positive predictive value of the screening mammography test given its sensitivity and 1-specificity as well as the prevalence of breast cancer in the relevant population. One version of the scenario was presented in the single-event probability format that is commonly used in the medical literature, while the other used the natural frequency representation. The two questionnaire versions were randomly assigned to the participants. RESULTS: Out of 200 residents, 153 completed and returned the questionnaire (response rate 76.5%). Although more than one-third of the residents reported excellent or close to excellent familiarity with sensitivity and positive predictive value, the majority of responses (79.1%) were incorrect. However, a significantly higher proportion of residents in the natural frequency group (n = 88) selected the correct response compared with residents (n = 65) in the single-event probability group (28.4% vs 10.8%; 95% confidence intervals of the difference between the two proportions = 5.6-29.7%; P < 0.01). DISCUSSION: Residents more often correctly understand test performance accuracy when test characteristics are presented to them as natural frequency representations than the more common approach of presenting single event probabilities. Educators and journal editors should be aware of this facilitative effect.

Complications Following Short Femoral Nail Fixation for Intertrochanteric Hip Fractures: A Retrospective Study.

The incidence of proximal femur fractures is increasing due to aging of the population. Intramedullary nails are the mainstay of treatment for intertrochanteric hip fractures mainly due to their better biomechanical properties compared to dynamic hip screw devices, shorter operative time, and less blood loss during surgery. However intramedullary nail fixation is not devoid of complications. The purpose of this study is to look at complications related to intramedullary nailing for intertrochanteric hip fractures in a major trauma center. A retrospective study was conducted including all patients having suffered an intertrochanteric femur fracture and treated with intramedullary nails from October 1, 2020, to October 1, 2022, in the Orthopaedic Surgery Clinic. The intramedullary hip systems used were the Stryker Gamma3 Nail and the VITUS PF Nail. All complications following the postoperative period were recorded in detail. Overall, 240 patients with a mean age of 82.3 years treated with hip intramedullary devices were identified. Superior cutout of the lag screw in two patients (females 90 and 87 years old) was identified 8 and 10 weeks following initial surgery. Avascular necrosis (AVN) of the femoral head was identified in one patient (male 81 years old) which occurred 12 weeks postoperatively. All three cases were revised by replacing the nail with cemented hemiarthroplasty. Periprosthetic fractures occurred in an 88-year-old male and a 73-year-old female following an injury distal to the stem and were managed by replacing the nail with a long stem device (Long Gamma3). One case of metalwork fracture was also recorded. There are many advantages in managing intertrochanteric hip fractures with intramedullary hip devices such as shorter theater time, less blood loss, and improved biomechanical properties. However, complications such as cutout of the lag screw, AVN, and periprosthetic fracture are serious and require complex revision surgery.

A pilot study investigating the use of at-home, web-based questionnaires compiling patient-reported outcome measures following total hip and knee replacement surgeries.

Patient-reported outcome measures (PROMs) are used routinely in NHS. Traditional pen-and-paper questionnaire collection can be time-consuming for both patients and clinic staff. The purpose of the current study was to determine whether a web-based PROMs system has the potential to provide satisfactory patient compliance and whether compiled data are equivalent to pen-and-paper PROMs data. A series of 82 patients who had joint replacement surgery was identified. Each patient was contacted by letter to register on the myClinicalOutcomes.co.uk website and to follow the instructions to render an Oxford score. A second request was sent to those failing to initially register. Telephone contact was then made with non-responders to identify the reason for failed registration. Successfully collated online Oxford scores were compared with previously recorded pen-and-paper scores for each patient from a prospectively updated database. Of the 82 patients identified, 61 (74%) received a letter or were otherwise contacted by telephone. Of these, 27 (44%) patients confirmed that they had access to the Internet. A total of 21 complete sets of data were collected. On review, the available secure online Oxford outcome scores demonstrated a mean of 30.1 (SD 11.4, range: 9-47). This mean score was comparable to the pen-and-paper database mean score of 29.1 (SD 11.8, range: 9-48) for the respective patients. Of the 27 respondents with Internet access, 21 (78%) produced complete scores that were available for real-time review. Available online scores were comparable to those collected via traditional means. With increased Internet availability and improved communication, remote web-based collection of patient reported outcomes may facilitate enhanced and efficient follow-up of patients.

The Impact of COVID-19 Pandemic in Orthopaedic Surgery Hospital Admissions and Workload in a Major Trauma Center.

The coronavirus disease 2019 (COVID-19) pandemic has led to important restrictions in social life of civilians worldwide and there were lower admission rates mainly in surgical departments in many hospitals. This study presents how COVID-19 pandemic affected admissions at the orthopaedic and trauma surgery department of a major trauma center. A retrospective study was conducted that recorded all patients examined at the outpatient orthopaedic clinic and the emergency orthopaedic department, as well as patients admitted to the orthopaedic surgery clinic and patients that underwent operative procedures between March 23 and May 4, 2020 (first lockdown period) and between March 23 and May 4, 2019 (control period). In addition, all patients with hip fractures that required hospitalization and underwent hip surgery were identified during the same time periods. During lockdown period 1 compared with the lock-down period 2 were observed: 70% and 61% decrease in the number of patients examined at the outpatient clinic and the emergency orthopaedic department respectively. The number of patients admitted to the orthopaedic surgery clinic declined by 41%, whereas operative procedures decreased by 22%. Regarding hip fractures timing to surgery during the first period was significantly less compared with second lockdown period, however, hospitalization days remained almost unchanged over the two time lockdown periods. Restrictions during the first lockdown period due to COVID-19 pandemic caused an important decrease in the number of patients and theaters in all orthopaedic departments in one of the major trauma centers in Athens. However, the incidence of hip fractures in elderly was not significantly decreased. Further similar studies are needed to identify variations and patterns of these parameters in other trauma centers.

Dynamic condylar screw as a solution to operative dilemma in early sub-trochanteric fracture following cannulated screw fixation for slipped capital femoral epiphysis: a case report.

A 14-year-old boy presented with a 2-month history of left groin pain and a limp on the left side. Radiographs confirmed slipped capital femoral epiphysis (SCFE) of the left hip. The surgical procedure he received used a single, 8-mm, partially threaded, cannulated screw. Postoperatively he was advised to remain strictly non-weight bearing on the affected lower limb until physeal closure was achieved. Unfortunately, he fell down 4 weeks postoperatively and sustained a subtrochanteric fracture on the same hip, with the cannulated screw still in place. This injury was surgically treated using a dynamic condylar screw and a side plate.

Hip pain and pseudo-lengthening of the leg due to iliopsoas haematoma following implantation of an uncemented component in acetabular cotyloplasty technique.

We report early symptomatic (groin pain and apparent limb lengthening) findings in our 12 consecutive patients who underwent total hip replacements using a cementless acetabular cotyloplasty technique. This report is the first in the literature to mention such an early complication in a large number of patients and also to describe early detection and treatment in these cases. During the period of January 2007 to December 2010, 12 patients (seven female, five male) with dysplastic hip underwent total hip arthroplasty. The mean age of the patients was 57 years (range 52-61 years) and the mean follow-up time was 18 months (12-36 months). A cotyloplasty technique was performed and uncemented acetabular and femoral components were implanted in all these 12 patients. All patients were reviewed postoperatively for clinical and radiographic assessment at six weeks, three months, six months, and one year, and then annually thereafter. During the first one to two months (mean time 22 ± 16 days), all patients complained of a constant pain in the groin that started in the early postoperative period. A pseudo lengthening of the operated hip and pelvic tilt was found on clinical examination at the three-month follow-up. The True length did not reveal a significant leg length discrepancy. Hip pain, pseudo lengthening, and pelvic tilt resolved within 123 ± 17 days post-op. A cotyloplasty technique using an uncemented acetabular implant can cause an intrapelvic hematoma of the iliopsoas muscle giving rise to temporary groin pain, pseudo lengthening on the operated side, and gait disturbances to the patient in the early postoperative period. Symptoms resolved completely in all of our cases. Iliopsoas physiotherapy could be useful and should be encouraged during the symptomatic period. Patients have to be informed during consenting and reassured about this symptomatology. Awareness of this likely complication would help surgeons to detect the problem and initiate treatment early.

Variations of Ulnar Nerve in the Forearm and Hand: A Review of the Literature and Clinical Significance.

The ulnar nerve originates from the anterior division of the lower trunk of the brachial plexus which continues as the medial cord and gives off branches to the forearm and the hand with motor and sensory fibers. The objective of the current study is to assemble the recognized anatomical variations of the ulnar nerve (UN) and underline their clinical impact. A literature search was undertaken via PubMed database, using the term: "ulnar nerve AND variations." Classical anatomical textbooks were also used for the normal anatomy of the UN. A total of 23 articles met the inclusion criteria, 16 of which are included in this review. Fifty-four additional articles provided useful information according to the aim of this review. Of great interest is the communication between the UN and the radial nerve (RN) in the forearm, as well as the communication between the UN and the median nerve (MN) in both forearm and hand. Furthermore, variations of the UN were observed in the hand and the classification of the UN compression was also described according to the point of the neuropathy. These collecting data are categorized into five tables. Additional aberrations were also included in this review. According to literature, the UN is characterized by numerous variations of its course and branches. Therefore, good knowledge of the normal anatomy is essential. Moreover, the anomalies are of particular importance due to their significant clinical implications and should be taken into consideration by the surgeons during surgical procedures in this region.

Is CT-A Always Reliable in Detecting Active Bleeding in Closed Pelvic Fractures? Management of a Case with Multiple Closed Pelvic Fratures and Internal Iliac Artery Bleeding.

One of the most important complications of pelvic injuries is hemorrhage which can be attributed to the venus plexus of the pelvis, the damaged bone on the fracture site, or in 15% of cases to arterial cause. In the last case mortality could reach 70%. Clinical case presentation, a 77-year-old man, presented in the emergency department of our hospital hemodynamically unstable due to fall from height (3 meters) with comminuted bilateral fractures of the pubic rami, right sacral and iliac wing fracture, right acetabular fracture, fractures of transverse processes of the first, second, and fifth lumbar spine vertebrae and a periprothetic fracture of the right femur. Advanced trauma life support (ATLS) protocol was followed throughout. Computed tomography (CT) scans and CT angiography performed, showed the above mentioned pelvic fractures that did not require stabilization, without further injuries, and a well described retroperitoneal hematoma without any evidence of active bleeding. During the resuscitation process the patient developed cardiac arrest and cardiopulmonary resuscitation (CPR) protocol was followed. The patient was intubated and retained his cardiac rhythm. However, he remained unstable and an angiography was then performed that revealed internal iliac artery bleeding and embolism of the internal iliac artery was performed. The patient was stabilized and was transferred to the intensive care unit for further management. Arterial hemorrhage due to pelvic injury is less common, however presents with high rates of mortality. CT angiography may in some cases not reveal existing active bleeding, misleading the clinician. Therefore, in patients with high clinical suspicion of arterial pelvic hemorrhage who remain unstable during the initial resuscitation and do not present with other primary source of bleeding, an angiography and embolism should be performed as soon as possible.

Surgical Removal of Bone Bridge and Interposition of the Extensor Digitorum Brevis in the Treatment of Calcaneonavicular Coalition in Pediatric Patients: A Case Series, Short Review, and Commentary.

This study retrospectively presents a single-clinic case series of pediatric patients with calcaneonavicular coalition treated by surgical removal of the bone bridge and interposition of the extensor digitorum brevis. This technique is currently the most cited and utilized protocol in operative treatment. Clinical, functional, and radiological results are analyzed and compared with related research. This is a single-clinic retrospective study, conducted for a period of 15 years. One independent investigator reviewed medical records and conducted a de-identified preoperative, inpatient, and postoperative assessment focused on demographic data, history and clinical evaluation, imaging assessment, American Orthopedic Foot and Ankle Society (AOFAS) scoring, and complication analysis. Of 34 patients, 13 met the inclusion criteria. Mean patient age was 11.2 years; 10 were males and 3 were females. Pathology concerned the right lower limb in eight cases and the left in five. Mean time between diagnosis and surgical intervention was 4.3 months and mean postoperative follow-up was 27.2 months. Thorough overview of reported symptoms, identified signs, imaging evaluation, functional outcomes, and adverse effects was performed. Bone bridge removal and interposition of the extensor digitorum brevis is an effective method of treating the condition. Despite drawbacks, results are comparable or even, to some degree, superior to other techniques.

Fusobacterium Nucleatum Causing Necrotizing Fasciitis of the Neck, Thorax, and Upper Limb: A Lemierre's-Like Case Presentation.

Necrotizing fasciitis (NF) is a rare "flesh-eating" entity with a high mortality rate due to late diagnosis. More specifically, this disease is deemed to be a subset of the aggressive skin and soft tissue infections (SSTIs) resulting in necrosis of the muscle fascia and subcutaneous tissues. It is usually caused by Gram-positive cocci specifically strains of Staphylococcus aureus and Streptococci or the combination of Gram-negative and anaerobic bacteria. If septic thrombophlebitis complicates a parapharyngeal abscess the clinical condition is referred to as Lemierre's syndrome (LS), which is also a rare entity and can result in necrotizing fasciitis of the neck and is usually caused by Fusobacterium necrophorum or Fusobacterium nucleatum. In our study, a rare case of a 61-year-old male patient who presented with progressed necrotizing fasciitis of his neck, chest, as well as his upper arm and a history of a bacterial throat infection in our emergency department is discussed. Despite treatment involving iv antibiotics and urgent radical surgical debridement, the patient unfortunately succumbed to his disease due to sepsis and secondary multiorgan failure.

Primary Extranodal Skeletal-Muscle Non-Hodgkin B Cell Lymphoma: Clinical Presentation and Diagnostic Approach.

Primary extranodal non-Hodgkin lymphomas that involve skeletal muscles (PSML) are infrequent with non- specific features or symptoms. Therefore, their diagnosis can be immensely convoluted since they mimic other soft tissue tumors and diseases (34). In this study, the case of a 61-year-old male patient, who presented with a history of a 6-week left thigh oedema and concomitant pain in our Emergency Department, is discussed. The patient was initially reviewed in another institution; the results of imaging studies (ultrasound scan) were consistent with deep vein thrombosis (DVT).Despite treatment, the patient's pain and swelling was exacerbating, which forced him to visit our hospital. Magnetic resonance imaging (MRI) revealed a diffused mass in his right thigh, while fine needle aspiration cytology (FNAC) yielded a diagnosis of B-cell lymphoid hyperplasia. The patient was then referred to a tertiary cancer treatment center for further management.

The Facts and Myths for the Use of Lasers in Orthopedic Surgery.

For the past three decades, laser use has been investigated, mainly on implant applications, as well as hard and soft tissue processing on orthopedics. However, despite significant technological advances and achievements in Biophotonics, lasers have yet to emerge as a successful tool for hard-tissue manipulation (e.g., osseous tissue). Indeed, a careful search in relevant literature reveals a limited number of laser-based clinical applications in orthopedics, except for the low-level laser therapy applications. In this review article, we give a brief overview of the biophysical mechanisms of bone tissue and biocompatible implants laser surgery and, in parallel, we summarize some specific pre-clinical and clinical laser applications in orthopedics. Taking into consideration the complexity of laser-based applications in inhomogeneous musculoskeletal biostructures and/or implants, it is justified to state that applying laser radiation is still an open field of multidisciplinary research before performing interventions in clinical praxis. The evidence from this study indicates the need for more experimental and theoretical studies regarding light transport on soft and hard tissues, in order to further enhance safe and efficient laser applications in orthopedics. This undoubtedly implies the need for developing modern light delivery devices for laser surgery, by means of implementing robotic guidance, specialized for medical procedures on various anatomic structures. The aforementioned studies could eventually revolutionize the clinical applications of laser technology in orthopedics.

Distraction Osteogenesis Technique for the Management of a Gustillo Type I Tibial Shaft Fracture Initially Managed with an Intramedullary Nail Device.

Fractures of the tibia shaft are the most common long bone fractures, especially in young male adults. Due to specific anatomical features, these fractures are more common than any other long-bone fracture. This is one of the main reasons they are associated with twice the incidences of deep infection compared with any other bone and can be combined with the presence of segmental bone defect. Many reconstruction techniques have been used to manage such cases, including Ilizarov technique, Masquelet technique, vascularized fibula transfer, and the monolateral external fixator. We present a case of a 21-year-old male patient who was admitted to our hospital for a Gustillo type I tibial shaft fracture which was initially treated by an intramedullary nail device. Two months postsurgery the patient presented with clinical signs of infection in the area of the fracture site, confirmed by an osteolytic lesion revealed radiographically. A surgical operation was performed that included a tibial osteotomy proximal to the defected bone, bone excision, and application of a LRS external fixation device. Antibiotic therapy was administrated based grown cultures, and regular follow-up X-ray revaluation was performed. After six months, the bone was radiologically united, the frame was removed, and the leg was protected in a walking boot while the patient used only partial weight bearing. The treatment of segmental bone defects associated with infection and soft tissue loss presents a great challenge, and the choice of the appropriate method requires further study.

Anatomical Variations of the Left Subclavian Artery and Their Significance in Clinical Practice.

We study variations of the aortic arch (AA) and its first branches, the brachiocephalic, common carotid, and subclavian arteries. Specifically, we describe anatomical variations of the left subclavian artery (LSA) and their significance in clinical practice. Such variations are commonly associated with congenital anomalies of the right-sided AA (RAA) and/or great vessels. A systematic search of the PubMed online database for studies of LSA variations and RAA, published between 2000 and 2020, produced a total of 73 articles for our study (n = 258 cases). Three of the most common variants were aberrant LSA (32.9%), RAA with mirror-image branching (49.6%), and isolated LSA (17.4%). Although RAA and LSA variations are rare, they may give rise to symptoms during the first stages of life or adulthood and may require surgical repair. Patients can remain asymptomatic, but incidental findings on imaging studies may lead to surgical interventions in areas of the neck or thorax. In such cases, planning the surgical procedure can be challenging, and possible implications must be considered.

Three-Dimensional (3D) Printing in Orthopedics Education.

Three-dimensional (3D) printing is a newly established concept in orthopedics compared with other industries. Surgical applications of 3D printing and tissue engineering have been investigated since the early 2000s, almost two decades after Charles Hull had patented the first device currently in use for additive manufacturing, also known as rapid prototyping or more commonly 3D printing, and whose initial formal appellation was stereolithography (SLA). Despite technological progress, substantial principles have largely remained unaltered. Training directly on patients and on cadavers is considered the "gold standard" for learning and developing suitable surgical qualifications. However, restrictions concerning patient safety, ethical dilemmas, lack of availability, etc., have to be taken into account. Thus, 3D representations can be utilized as an educational tool both for patients to improve their understanding of their condition and also medical students, residents, and surgeons to comprehend complex anatomical structures and practice their surgical maneuvers to be prepared and more confident in theater.

Bilateral Floating Knee Injury-Management of a Complex Injury.

Floating knee is a flail knee joint resulting from fractures of the shafts or adjacent metaphyses of the femur and ipsilateral tibia. Floating knee injuries may include a combination of diaphyseal, metaphyseal, and intra-articular fractures. Floating knee injuries are a group of complex injuries that require a careful assessment. This injury is generally caused by high-energy trauma with often extensive trauma to the soft tissues. There may also be life-threatening injuries to the head, chest, or abdomen and a high incidence of fat embolism. This complex injury has increased in proportion to population growth, number of motor vehicles on the road, and high-speed traffic. Although the precise incidence of a floating knee is not known, it is a relatively uncommon injury. Bilateral floating knee injuries are extremely rare, and there is only one case report in the literature with bilateral floating knee injuries. We present a case report of a 64-year-old lady who suffered a blunt abdominal injury (hemicolectomy and splenectomy) and bilateral floating knees during road traffic accident. We also offer guidance for the treatment of this complex injury, based on literature review.

Lower Limb Stump Fistula Treated with Laser Ablation. A Possible Alternative Minimal Invasive Technique.

Stump-wound infections are a common cause of complications after amputation. Wound infections, usually after major lower-limb amputation, vascular disease, or trauma, may lead to fistula formation. The main therapeutic options for these infections include antibiotic administration alone or antibiotic treatment in combination with surgery. Fistula management may require multiple surgical interventions that increase morbidity and cost and require long-term treatment prohibiting early mobilization of patients. We present a novel technique based on diode laser energy to destroy the fistula tract. This method has been applied on two patients with excellent results. It is easy to perform, safe, repetitive, well tolerated, and it can be performed under local anesthesia. This technique seems to offer excellent results.

The Use of Vacuum Closure-assisted Device in the Management of Compound Lower Limb Fractures with Massive Soft Tissue Damage.

The simultaneous exposure of tissue and bone poses specific management challenges. Patients with extended soft tissue damage and high-grade compound fractures present a demanding clinical challenge, requiring a complex approach and multiple orthopaedic, plastic, and vascular-reconstructive procedures. Management involves combinations of wound debridement and closure by secondary intention, use of vacuum-assisted closure (VAC) devices, and various reconstructive plastic surgery methods. We present three consecutive complicated cases, involving compound fractures of the lower limb with massive soft tissue damage (Gustilo-Anderson type IIIB) that were managed with debridement, application of external fixation and VAC device. The mean wound size was 24 cm in length and 12 cm in width. The aim of treatment was to cover the bone with soft tissue and achieve healing of the fracture without persistent infection. Wound healing was achieved in all three cases within 30-42 days (mean 34). In one case, the skin graft was applied on day 33. Utilizing this method as part of a multi-directional approach, the VAC system helps the patient recover faster. Moreover, it acts as a feasible and valuable method to treat compound fractures with massive soft-tissue defects. VAC can replace microsurgical soft-tissue transfer, reduce the risk of infection and allow salvaging the limb.

Spontaneous Knee Hemarthrosis Due to Hypofibrinogenemia Following Tigecycline Treatment for Periprosthetic Joint Infection.

Tigecycline, a recently approved antibiotic, has a broad spectrum of antimicrobial activity. Its unique structure and properties make tigecycline a valuable option for the treatment of infections caused by many multidrug-resistant organisms. We present a case of an 82-year-old patient who developed a significant decrease of fibrinogen levels after the addition of tigecycline to his antibiotic regimen. The patient was treated for a periprosthetic knee joint infection caused by a multidrug-resistant extended-spectrum beta-lactamase-producing Escherichia coli. The reduction of fibrinogen levels, in this case, prompted severe spontaneous hemarthrosis. Tigecycline treatment was discontinued and coagulation disorders were normalized within the next few days. After several days, the joint had to be surgically debrided. Hypofibrinogenemia is a very scarcely reported side effect of tigecycline that can cause spontaneous hemarthrosis.

Patella Height in Different Ethnic Populations: An Observational Multicenter Study.

Patella height appears to have a crucial role in knee biomechanics. Patellar malalignment and maltracking are therefore believed to be associated with development and progression of patellofemoral pain and disease. Published data are scant regarding the effect of everyday tasks on patella height and patellofemoral disease. We included 150 subjects in a retrospective observational study. Group A had 75 subjects (24 male and 51 female, with a mean age of 58.5 yr), whose daily activities included squatting (the traditional Muslim praying position called Sujud). Group B had 75 subjects (42 male and 33 female, with a mean age of 47.6 yr), who were non-Muslim. Patella height was measured using Insall-Salvati (IS) and Blackburne-Peel (BP) ratios. The mean IS ratio was 0.86 (confidence interval [CI]: 0.7-1.02) for group A and 1.1 (CI: 0.96-1.23) for group B. The mean BP ratio was 0.66 (CI: 0.49-0.83) for group A and 0.89 (CI: 0.73-1.04) for group B. We found 26 subjects (34.7%) in group B to have patella alta, when measured by either ratio, compared to one subject (1.3%) in group A (p < 0.01) with patella alta. We found 61 subjects (81.3%) in group A to have patella baja, when measured by either ratio, compared to 21 subjects (28%) in group A (p < 0.01) with patella baja. In group A, the IS ratio was reduced in 29 subjects (38.7%), the BP ratio was reduced in 59 subjects (78.7%), and both were reduced in 27 subjects (36%). A similar pattern was noted for group B. Our results show that a significant increase in patella baja was associated with repeated squatting/kneeling, compared to the predominance of patella alta in the control group. On the basis of these findings, we hypothesize that biomechanical stresses associated with repeated hyperflexion of the knee asymmetrically affect the more flexible quadriceps muscle fibers greater than patella tendon fibers. Thus, repeated hyperflexion in everyday tasks leads to elongation of quadriceps fibers and patella baja.