The 100 Top-Cited Articles on Medial Patellofemoral Ligament: A Bibliometric Analysis and Review.

Background: The medial patellofemoral ligament (MPFL) has been investigated widely in the past 30 years, resulting in many research achievements in this field. Purpose: To perform a comprehensive bibliometric analysis to evaluate the 100 top-cited articles on the MPFL. Study Design: Cross-sectional study. Methods: We searched the Scopus database in December 2022 using the terms "medial patellofemoral ligament" OR "MPFL." The search was confined to English-language articles, including technical notes, systematic reviews on clinical outcomes and/or complications, clinical studies, studies regarding complications, and basic science articles (either cadaveric or biomechanical); we excluded letters, case reports, personal opinions, guidelines, editorials, and narrative or other types of reviews. Analysis of the 100 top-cited articles was performed according to total number of citations, average citations per year (ACY), study type, country of origin, journal of publication, affiliated institution, and most published authors. Results: The total number of citations was 16,358 (range of citations per article, 72-692). The majority of articles were published as clinical studies (54%), with cadaveric studies being the second most common (21%). Most studies originated in the United States (32%), with Japan (15%) and Germany (13%) following. The American Journal of Sports Medicine published the majority of the 100 top-cited articles (37/100; 6304 citations) as well as the 10 top-cited articles according to ACY (7/10; mean, 285.14 citations). The most prolific authors were Nomura (8 articles); Burks (6 articles); and Inoue, Sillanpää, and Dreyhaupt (5 articles each). Conclusion: By analyzing the characteristics of the 100 top-cited articles, this study demonstrated that the MPFL is a growing and popular area of research, with the focus varying through timeline trends. Questions regarding MPFL anatomy, isometry, and biomechanics might have been answered adequately, but research regarding optimal fixation technique under various circumstances is still ongoing.

Anatomy and terminology of groin pain: Current concepts.

Groin pain is a common symptom in athletes. The complex anatomy of the area and the various terms used to describe the etiology behind groin pain have led to a confusing nomenclature. To solve this problem, three consensus statements have been already published in the literature: the Manchester Position Statement in 2014, the Doha agreement in 2015, and the Italian Consensus in 2016. However, when revisiting recent literature, it is evident that the use of non-anatomic terms remains common, and the diagnoses sports hernia, sportsman's hernia, sportsman's groin, Gilmore's groin, athletic pubalgia, and core muscle injury are still used by many authors. Why are they still in use although rejected? Are they considered synonyms, or they are used to describe different pathology? This current concepts review article aims to clarify the confusing terminology by examining to which anatomical structures authors refer when using each term, revisit the complex anatomy of the area, including the adductors, the flat and vertical abdominal muscles, the inguinal canal, and the adjacent nerve branches, and propose an anatomical approach, which will provide the basis for improved communication between healthcare professionals and evidence-based treatment decisions.

Anterior and Posterior Cruciate Ligaments Mechanoreceptors: A Review of Basic Science.

Proprioception is a specialized sensory modality encompassing the movement of the joint and its position in space, and it involves the conversion of mechanical deformation of tissues into neural signals. Mechanoreceptors are specialized nerve structures able to transmit mechanical deformation through electrical signals to dorsal root ganglion sensory neurons and are abundant in the muscles, tendons and ligaments of the knee joint. They are believed to play an important role in knee proprioception and dynamic knee stability. Proprioception should always be taken into consideration for successful reconstruction of the cruciate-deficient knee and for pain and function management in the arthritic knee. Advances in histological methods of detection are numerous and continue to highlight the presence and role of mechanoreceptors after ligament reconstruction, depending on choice of graft. In this review, we present the current knowledge of anterior and posterior cruciate ligaments and grafts mechanoreceptors, and their role in proprioception of knee joint, focusing on each type of mechanoreceptors.

A Review of the Outcomes of the Implementation of Case-Based Anatomy Learning.

PURPOSE: Clinically-oriented anatomy education has been proposed as an effective strategy in anatomy curricula. We aimed to explore the level of extent the literature supports the fact that case-based learning (CBL) can play a significant role in anatomy education. MATERIALS AND METHODS: We searched PubMed, Scopus, Education Resources Information Center (ERIC), and Cochrane database to find articles with the purpose to explore the educational outcomes of case-based anatomy learning. We extracted from each paper authors, type of study (comparative or not), number of participants, level of outcome according to the Kirkpatrick hierarchy, outcomes of CBL concerning the acquisition of anatomical knowledge, and the participants' perceived enjoyment, motivation, and aid to anatomy learning. RESULTS: Nine articles were included. Three of them evaluated the acquisition of anatomical knowledge, while six papers evaluated the participants' perceptions. All studies showed positive outcomes regarding the students' anatomy examination performances, reported confidence, enjoyment, motivation, and ability of CBL to facilitate anatomy learning. CONCLUSION: Although the existing research has mainly evaluated students' perceptions, the outcomes of CBL in anatomy education encourage more extensive use of this method in anatomy curricula. Further research is expected to shed more light on the role that CBL can play in modern anatomy education and to clarify if it can replace or supplement didactic teaching.

Knee Capsule Anatomy: An MR Imaging and Cadaveric Study.

This research focuses on the anatomical insertion of the synovial capsule around the knee. The attachments of the capsule were measured in 50 knee MR imaging studies with large intraarticular effusion. Corresponding measurements were performed in 20 fresh frozen cadaveric specimens, for validation. Femoral and tibial capsular reflections were defined as the distances between the attachment sites of the capsule and the femoral or tibial joint line and they were recorded in three coronal planes (anterior/middle/posterior). On MR imaging, the lateral/medial femoral capsular reflection mean values were 6.5/4.57 cm, 2.74/1.74 cm and 1.52/1.99 cm in the anterior, middle and posterior plane, respectively. MR imaging-based measurements did not differ significantly compared to corresponding cadaveric measurements. The mean values of the lateral/medial tibial capsular reflection on MR imaging were 0.09/0.11 cm, 0.34/0.26 cm and 0.62/0.34 cm in the anterior, middle and posterior plane, respectively. On cadaveric dissection, the maximum mean value was 1.45 cm, measured on the lateral side of the anterior plane. Apart from the lateral aspect of the posterior plane, MR imaging measurements were significantly lower, compared to the corresponding cadaveric measurements. The greatest femoral and tibial capsular reflections were found on the anterior and lateral side of the anterior plane. MR imaging appears to underestimate the distal extent of the knee capsule. Anatomical details of the knee capsule should be considered for safe insertion of external fixator pins.

Surgical Implications of the Arterial Anatomy around the Knee: A Cadaveric Pictorial Essay.

We completed an anatomic cadaver study in order to examine the arterial supply around the knee and to create useful images regarding the arterial surgical anatomy around the knee. A total of four unmatched fresh-frozen cadaveric knees were utilized. There was no medical history of osteoporosis, bony or soft-tissue injury or surgery in any of the knees. The femoral arteries were cannulated with a large catheter at the proximal aspect of the cadavers, and liquid latex in different colours was injected. Τhe specimens were then placed into a bath of 8.0% sodium hypochlorite to complete debridement of the soft tissues to various degrees. The specimens were checked every 15 to 30 min until adequate debridement occurred, and photographs were taken during each stage of this process. Sodium hypochlorite, among others, chemically debrides the vessel walls leaving the casts of the vessel lumens filled with solid coloured latex in order to illustrate the vascular supply pattern to the structures of interest. Knowing the probability of where these arteries should be located adds to the knowledge that surgeons have at their disposal when performing procedures involving arthroscopy, arthroplasty and osteotomies, which can help decrease unnecessary damage to the arteries.

Surgical and Radiological Anatomy of the Medial Patellofemoral Ligament: A Magnetic Resonance Imaging and Cadaveric Study.

The purpose of this study was to compare the measurement of several anatomical features of the medial patellofemoral ligament (MPFL) between magnetic resonance imaging (MRI) and by direct fashion during dissection. We hypothesized that the measurements between these two techniques would agree. MRI of 30 fresh-frozen cadaveric knees was followed by dissection. MPFL patella and femoral attachment were evaluated; their shape, length, and width were measured; and measurements were compared. MRI was deemed unreliable for the determination of several of the aforementioned anatomical features. Important findings include: (a) observations on MPFL attachment at medial patella side and attachment to quadriceps were identical between dissection and MRI; (b) average width at patella insertion was significantly different between the two methods (p = 0.002); and (c) an attachment to the quadriceps tendon was present in 20/30 specimens and d. detailed measurements of a thin, non-linear, and three-dimensional structure, such as the MPFL, cannot be performed on MRI, due to technical difficulties. This anatomical radiological study highlights the shape, anatomical measurements (length and width), and attachment of the MPFL using a relatively large cadaveric sample and suggests that MRI is not reliable for detailed imaging of its three-dimensional anatomy.

Simultaneous bilateral posteromedial tibial epiphysis stress fractures in a healthy young man: A case report.

We present a compelling case of simultaneous, bilateral tibial stress fractures occurring in a unique epiphyseal and posterior location, with unclear aetiology. An overweight, Caucasian male in his late 20s developed synchronous bilateral medial knee pain following an intense 10-day training regimen. His radiographies were normal, but MRI revealed almost identical bilateral stress fracture lines in the posteromedial tibial epiphyses. Bone mineral densitometry and a full metabolic and hormonal panel were performed to further investigate potential underlying metabolic bone disease. He was found to have normal bone mineral densitometry and low Vitamin D serum values. Symptomatology greatly improved with activity modification. There were no further complaints and complications at 12 months' follow-up. Diagnosis can be challenging and the treating physician should be acquainted with the basic science of stress fractures and main discriminating clinical, biochemical and radiological characteristics from insufficiency fractures, to avoid pitfalls in treatment decision.

University Students Perception of Online Education: Is Engagement Enough?

BACKGROUND: Universities have halted non-essential services, with many restricting campus-based teaching, and continuing courses through online resources, including (controversially) lab-work. Such technologically enhanced approaches have been proven to have high levels of engagement among university students. OBJECTIVE: This study focuses on the perception of quality of online learning by first-year university students, between two semesters, amidst the COVID-19 pandemic. METHODS: A 24-item questionnaire was designed with Likert response scale. It consisted of general perception questions of academic life and questions specific to the quality of delivery of a specific class. Eighty one eligible students were asked to fill the same questionnaire for each semester. Students' responses and their grades from the final exams in each semester were compared. RESULTS: Out of 81 eligible students, 75.31% of students responded to the survey. They were less interested in their studies in the second "online" semester (p=0.05). Students expressed dissatisfaction with the quality of online classes (p=0.03). Academic life fulfillment was also affected (p=0.02). Students' perception of the amount of free time they had between semesters did not change significantly (p=0.16). Students appeared dissatisfied with their active participation during the online class (p=0.007), even though they felt less stressed attending lectures from home (p=0.041). However, they found that workload was bearable and similar between semesters (p=0.83). Students also had significantly more trouble concentrating during online lectures (p<0.001). Students' grades significantly improved by an average of 1.07 (out of 10) in the final exams at the end of the second semester (p<0.001). CONCLUSION: These unprecedented circumstances require innovation and cooperation on the part of university programs to maintain rigorous standards of higher education, taking into account students' evolving perception and needs.

A computed tomography cadaveric study of the radiological anatomy of the patella: the size of the patella correlates with bone bridge between tunnels and R angles are introduced for safe tunnel drilling during MPFL reconstruction.

PURPOSE: To measure the safe range of angles during tunnel drilling and map ideal patella tunnel placement with the use of preoperative computed tomography (CT) scan and compare results after medial patellofemoral ligament (MPFL) reconstruction using a hardware-free patellar fixation technique with two semi-patellar tunnels between a) a free-hand technique, and b) its modification with the use of an anterior cruciate ligament (ACL) tibia aiming device. METHODS: CT scan was performed on 30 fresh-frozen cadaveric knees a) prior to any intervention and b) after MPFL reconstruction. For MPFL reconstruction, specimens were randomly allocated to 1) Group A, which consisted of knees operated with free-hand, hardware-free patellar fixation technique with two semi-patellar tunnels and 2) Group B, which consisted of knees operated on with a technique modification with the ACL tibia device. PATELLAR MEASUREMENTS: L1 was the maximal patellar length. L2 was the minimum possible distance of placement for the upper tunnel from the proximal pole of the patella. The maximum bone bridge between tunnels was calculated as half of L1 minus the L2 distance (L1/2-L2). We also measured R1 and R2 angles at the proximal and distal tunnel that represent safe angles at the entry point during tunnel drilling (without breaching the anterior cortex or articular cartilage). RESULTS: Preoperatively, mean L1 was 3.45 cm (range 3.05-4.52). Mean L2 was 0.62 cm (range 0.49-0.89). The mean maximum possible bone bridge between tunnels (L1/2-L2) was 1.1 cm (range 0.77-1.58). R1 was 6.050 (range 4.78-7.44), R2 was 6.640 (range 4.57-9.03), and their difference reached statistical significance (p = 0.03). Postoperatively, in group A, in 4 out of 15 patellas, multiple attempts were made during tunnel drilling in order to avoid anterior cortex or cartilage breaching. In group B, all tunnels were correctly drilled with the first attempt. Bone bridge between tunnels was significantly shorter postoperatively (0.93 cm, p < 0.01). CONCLUSION: Small-size patellae correlate with short maximum bone bridge between tunnels, which makes anatomic, double-bundle, hardware-free patella fixation, with two semi-patellar tunnels MPFL reconstruction challenging. Furthermore, R angles create a narrow window to avoid intraoperative breaching, rendering the use of the ACL tibia device an extremely useful instrument. LEVEL OF EVIDENCE: II.

Primary Paraspinal Hydatid Cyst in a Patient Presenting with Low Back Pain: A Case Report.

CASE: A 54-year-old man presented with low back pain and low-grade fever. Palpation revealed a focal mass of the lumbar region. Radiographs were normal, but magnetic resonance imaging demonstrated a multicystic mass at the level of L2-L4. The initial diagnosis of a hydatid cyst was confirmed after surgical excision. CONCLUSION: Although primary paraspinal hydatidosis is rare, physicians should be aware of it when dealing with patients suffering from low back pain combined with red-flag symptoms. Especially in rural regions or areas where populations live in close proximity to host animals, primary paraspinal hydatidosis should be included in the differential diagnosis.

Musculoskeletal anatomy: evaluation and comparison of common teaching and learning modalities.

Anatomy teaching has traditionally been based on dissection. However, alternative teaching modalities constantly emerge, the use of which along with a decrease in teaching hours has brought the anatomy knowledge of students and young doctors into question. In this way, the goal of the present study is to a. compare the efficacy of the most common teaching modalities and b. investigate students' perceptions on each modality. In total, 313 medical students were taught gross anatomy of the upper limb, using four different learning modalities: dissection (n = 80), prosections (n = 77), plastic models (n = 84) and 3D anatomy software (n = 72). Students' knowledge was examined by 100 multiple-choice and tag questions followed by an evaluation questionnaire. Regarding performance, the dissection and the 3D group outperformed the prosection and the plastic models group in total and multiple-choice questions. The performance of the 3D group in tag questions was also statistically significantly higher compared to the other three groups. In the evaluation questionnaire, dissection outperformed the rest three modalities in questions assessing students' satisfaction, but also fear or stress before the laboratory. Moreover, dissection and 3D software were considered more useful when preparing for clinical activities. In conclusion, dissection remains first in students' preferences and achieves higher knowledge acquisition. Contemporary, 3D anatomy software are considered equally important when preparing for clinical activities and mainly favor spatial knowledge acquisition. Prosections could be a valuable alternative when dissection is unavailable due to limited time or shortage of cadavers. Plastic models are less effective in knowledge acquisition but could be valuable when preparing for cadaveric laboratories. In conclusion, the targeted use of each learning modality is essential for a modern medical curriculum.

Reconstruction of the medial patellofemoral ligament using two blind transverse semi-patella tunnels and an implant-free technique for patellar fixation: a technical note.

BACKGROUND: The double-bundle technique with two points of patellar fixation in the upper half of the patella replicating the broad attachment site of the native medial patellofemoral ligament (MPFL) is the most commonly performed procedure for MPFL reconstruction. Complete transverse patella tunnels pose a threat to the integrity of the patella. We present an implant-free, double-bundle technique for MPFL reconstruction with gracilis autograft, overcoming the problem of complete patella bone tunnels and over-drilling. METHODS: After standard gracilis graft harvesting, the anteromedial side of the patella is exposed. With the guidance of an anterior-cruciate-ligament (ACL) tibia-aiming device, two 2-mm parallel guide pins are inserted from medial to lateral at the upper half of the patella. The two guide pins are over-drilled with a cannulated 4.5-mm drill bit 2-cm deep, to create two transverse blind semi-patellar tunnels. For the femoral fixation, a 2.4-mm guide pin with an eyelet is drilled at the Schöttle point and over-reamed with a 6-mm cannulated reamer to a depth of 30 mm. The two free ends of the graft (with two running Krakow sutures placed) are pulled into the two patella tunnels and the graft sutures are tied together with tension for stable graft fixation at the lateral patella rim. With the help of a femoral suture loop (which is inserted in the femoral bone tunnel), the graft-loop is advanced into the femoral bone tunnel and the graft is finally fixed with a 7-mm interference screw at 30° of knee flexion. RESULTS: The utilization of blind transverse tunnels (not trans-patellar tunnels) offers the advantage of avoiding stress risers at the patella. Thanks to the ACL tibia aiming device, multiple drilling, and breaching of the anterior patellar cortex or articular surface of the patella is avoided. CONCLUSIONS: This implant-free, and consequently affordable technique, isolated or combined with bony procedures, minimizes possibilities for perioperative bony complications at the patella fixation site.

Questioning the therapeutic value of corticosteroid bursal injection after ultrasound-guided irrigation and lavage for the treatment of shoulder calcific tendinosis.

OBJECTIVES: The therapeutic value of corticosteroid bursal injection after ultrasound-guided irrigation and lavage for the treatment of shoulder calcific tendinosis has not been established yet in the long term. METHODS: 41 patients suffering from chronic symptomatic rotator cuff calcific tendinopathy were recruited for this study. Group A (20 patients) received a double needle ultrasound-guided irrigation and lavage of the calcification with xylocaine injection, while group B (21 patients) underwent a double needle ultrasound-guided irrigation and lavage of the calcification with a xylocaine and betamethazone bursal injection. RESULTS: After twelve months, we documented full -or almost full- decline (VAS: 0-20/100) of the symptoms in 70% of the group A patients and in 61.9% of the group B patients. There was no statistical difference (chi square, p < 0.05) in group success ratio. We also did not find any statistical difference as for the mean Q-DASH difference between the two groups (t-test). CONCLUSIONS: It was proven that the additional use of corticosteroid bursal injection did not provide with any additional short- to mid-term therapeutic benefit those patients with shoulder calcific tendinopathy who were treated with ultrasound-guided aspiration.

Iliac Crest Bone Grafting for the Management of Anterior Shoulder Instability in Patients with Glenoid Bone Loss: a Systematic Review of Contemporary Literature.

BACKGROUND: A number of clinical trials have been published assessing the role of iliac crest bone grafting for the management of recurrent anterior instability with glenoid bone loss in contemporary practice. We therefore performed a systematic review of contemporary literature to examine the effect of iliac crest bone grafting on postoperative outcomes of these patients. Our hypothesis is that contemporary iliac crest bone block techniques are associated with low reoperation and complication rates combined with satisfactory functional results. METHODS: The US National Library of Medicine (PubMed/MEDLINE), the Cochrane Database of Systematic Reviews, and EMBASE were searched between January 2008 and December 2019 for relevant publications. RESULTS: Following the application of the inclusion-exclusion criteria, nine articles were found eligible for our analysis. In total, 261 patients (mean age range, 25.5-37.5 years; mean follow-up range, 20.6-42 months) were included in the studies of the current review. The mean modified Coleman score was 48.6 (range 37-65), indicating an overall low-to-moderate methodological quality. In the short term, the overall all-cause reoperation rate was 6.1%, while the rate of recurrent instability was 4.8%. The graft non-union rate was 2.2%, while the rate of osteolysis, graft fracture, and infection was 0.4%, 0.9%, and 1.7%, respectively. Finally, hardware-related complications, such as screw breakage or symptomatic mechanical irritation around the screw insertion, occurred in 3.9% of the patients. CONCLUSIONS: Iliac crest bone block techniques in contemporary practice are safe and effective in the short-term (< 4 years) follow-up for the management of anterior shoulder instability with substantial glenoid bone deficiency. However, further studies of higher quality and longer follow-up are required to establish the therapeutic value of these techniques as well as to clarify whether there are differences in the outcomes of arthroscopic and open iliac crest bone block procedures.

Lower incidence of post-operative septic arthritis following revision anterior cruciate ligament reconstruction with quadriceps tendon compared to hamstring tendons.

PURPOSE: To determine and compare the incidence of post-operative septic arthritis following revision anterior cruciate ligament reconstruction (R-ACLR) with autologous quadriceps tendon (with patellar bone block) compared to autologous hamstring tendons (semitendinosus and gracilis). METHODS: A total of 1638 isolated R-ACLR with either autologous hamstring tendons (n = 1004, 61.3%) or quadriceps tendon (n = 634; 38.7%) were performed between 2004 and 2017 and were retrospectively analysed with regard to the occurrence of post-operative septic arthritis. The technique of R-ACLR did not significantly change during the years of the study. All patients received pre-op i.v.antibiotics, but no presoaking of the grafts in vancomycin was performed in the years of the study. The individual decision of graft choice was based on graft availability, tunnel position and the presence of tunnel widening. Generally, hamstring tendons were preferred. There were no clinically relevant differences between the groups regarding gender or age. Routine follow-up examination was performed 6 weeks after the index operation (follow-up rate 96.5%), and patients unsuspicious for septic arthritis at that time were classified as non-infected. RESULTS: Fourteen patients with septic arthritis were identified, resulting in an overall incidence of 0.85%. There was one patient with septic arthritis in the quadriceps tendon group (incidence: 0.16%) and 13 patients in the hamstring tendons group (incidence: 1.29%), respectively. The difference was significant (p = 0.013). CONCLUSION: In this series, the incidence of post-operative septic arthritis after R-ACLR was lower when quadriceps tendon graft was used compared to hamstring tendon grafts. LEVEL OF EVIDENCE: III.

Correction to: Congenital orthopaedic limb deformities in Corpus Hippocraticum.

The word "limb" in the article title was misspelled with a "p" at the end. The correct title is: Congenital orthopaedic limb deformities in Corpus Hippocraticum which is also given above.

Congenital orthopaedic limp deformities in Corpus Hippocraticum.

During the fifth century BC in ancient Greece during the eve of orthopaedics, the Hippocratic School of Medicine diagnosed a series of congenital limb deformities. Congenital dislocation of the arm, elbow, wrist, hip, knee, tarsotibial joint, apex leg, as well as talipes valgus (clubfoot), congenital clavicle fractures, and thumb malfunction were all discussed by Hippocrates and his followers. Ancient Greek medico-philosophers, fond of a "perfect" human body, proposed an immediate non-interventional approach, while archaic orthotics and specialized footwear were suggested. The Hippocratic methodology was once more re-emerged in the sixteenth century by Ambroise Paré and in the nineteenth century by Wilhelm Roser, becoming since then the main principle for the confrontation of congenital deformities. Various surgeons until nowadays are still being influenced by the Hippocratic doctrine.

A Narrative Review of Four Different New Techniques in Primary Anterior Cruciate Ligament Repair: "Back to the Future" or Another Trend?

Recently, four different operative techniques, referring to the primary anterior cruciate ligament (ACL) repair, were described. These are the dynamic intraligamentary stabilization (DIS) with Ligamys™, the Bridge-enhanced repair (BEAR), the use of internal brace, and the refixation with suture anchors. The purpose of this study was to assess the already-published, clinical, and pre-clinical results of those techniques. A literature review was conducted and implemented by three independent researchers. Inclusion criteria were clinical or cadaveric or animal studies about patients suffering from ACL rupture, who were treated with one of those four different arthroscopic techniques of primary ACL repair. There were 10 clinical trials dealing with the different techniques of primary ACL repair and 12 cadaveric or animal studies. The majority of the published clinical trials investigated the dynamic intraligamentary stabilization (DIS), while only four studies referred to the three other surgical techniques. Most of the clinical trials suggested that primary ACL repair should be done during the first 14-21 days after a proximal ACL rupture and not later. Further clinical evidence is needed for the techniques of bridge-enhanced ACL repair, internal brace, and suture anchors ACL refixation in order to support the animal and cadaveric biomechanical studies. Till now, the existing clinical trials were not enough to establish the use of those techniques in the ACL-ruptured patients. On the contrary, the Dynamic intraligamentary stabilization with Ligamys™ device demonstrated very promising results in different types of clinical studies.

Morel-Lavallée Lesions of the Knee: MRI Findings Compared With Cadaveric Study Findings.

OBJECTIVE: The purpose of this study is to describe the MRI findings and treatment decisions and outcome for Morel-Lavallée lesions (MLLs) of the knee and to investigate whether evidence exists to support an increased frequency of such lesions on the medial or lateral side by performing a cadaveric experiment. MATERIALS AND METHODS: In a 4-year period, 24 MRI studies of 24 consecutive patients (16 male patients and eight female patients) with knee MLLs were retrospectively reviewed. Patient demographic characteristics, treatment decisions and outcome, and associated injuries were recorded. The location of the MLL was categorized as medial, lateral, or global. Lesions were categorized according to an established MRI classification. During the cadaveric experiment, the compartmental pressures of the medial or lateral aspect of the knee were monitored in 20 cadaveric knees. The chi-square test, t test, and Pearson correlation were used for statistical analysis. RESULTS: MLLs were located medially in 16 patients, laterally in two patients, and globally in six patients. The medial location was significantly more common than a lateral or global location (p < 0.05). MLLs were classified as type I in 14 patients, type II in eight patients, and type III in two patients. MRI type was correlated with the chronicity of injury (r2 = 0.614; p = 0.0014). Fractures were the most common associated injuries, occurring in seven of 24 patients. In 17 patients, all of whom had conservatively treated type I or type II lesions, complete resolution of the MLL occurred. The maximum compartmental pressures were significantly higher on the lateral side than on the medial side (p < 0.0001). CONCLUSION: Knee MLLs have a predilection for the medial side, which may be attributed to the lower resistance in this location, and they have variable patterns on MRI, which correlate with chronicity. Conservative treatment of type I and II lesions seems effective.