The Dejour classification for trochlear dysplasia shows slight interobserver and substantial intraobserver reliability.

PURPOSE: Trochlear dysplasia is one of the main risk factors for recurrent patellar dislocation. The Dejour classification identifies four categories that can be used to classify trochlear dysplasia. The purpose of this study is to evaluate the inter- and intraobserver reliability of the Dejour classification for trochlear dysplasia. The hypothesis was that both intra- and interobserver reliability would be at least moderate. METHODS: This is a cross-sectional, reliability study. Twenty-eight examiners from the International Patellofemoral Study Group 2022 meeting evaluated lateral radiographs of the knee and axial magnetic resonance images from 15 cases of patellofemoral instability with trochlear dysplasia. They classified each case according to Dejour's classification for trochlear dysplasia (A-D). There were three rounds: one with only computed radiograph (CR), one with only magnetic resonance imaging (MRI) and one with both. Inter- and intraobserver reliability were calculated using κ coefficient (0-1). RESULTS: The mean age of patients was: 14.6 years; 60% were female and 53% had open physis. The interobserver reliability κ probabilities were 0.2 (CR), 0.13 (MRI) and 0.12 (CR and MRI). The intraobserver reliability κ probabilities were 0.45 (CR), 0.44 (MRI) and 0.65 (CR and MRI). CONCLUSION: The Dejour classification for trochlear dysplasia has slight interobserver reliability and substantial intraobserver reliability. LEVEL OF EVIDENCE: Level I.

Dorsal hippocampus to nucleus accumbens projections drive reinforcement via activation of accumbal dynorphin neurons.

The hippocampus is pivotal in integrating emotional processing, learning, memory, and reward-related behaviors. The dorsal hippocampus (dHPC) is particularly crucial for episodic, spatial, and associative memory, and has been shown to be necessary for context- and cue-associated reward behaviors. The nucleus accumbens (NAc), a central structure in the mesolimbic reward pathway, integrates the salience of aversive and rewarding stimuli. Despite extensive research on dHPC→NAc direct projections, their sufficiency in driving reinforcement and reward-related behavior remains to be determined. Our study establishes that activating excitatory neurons in the dHPC is sufficient to induce reinforcing behaviors through its direct projections to the dorso-medial subregion of the NAc shell (dmNAcSh). Notably, dynorphin-containing neurons specifically contribute to dHPC-driven reinforcing behavior, even though both dmNAcSh dynorphin- and enkephalin-containing neurons are activated with dHPC stimulation. Our findings unveil a pathway governing reinforcement, advancing our understanding of the hippocampal circuity's role in reward-seeking behaviors.

Correction to: Recognition of evolving medial patellofemoral anatomy provides insight for reconstruction.

Unfortunately, the middle name of author was incorrectly published as Jorge A. Chahla instead of Jorge Chahla in the original article.

Recognition of evolving medial patellofemoral anatomy provides insight for reconstruction.

PURPOSE: The scientific literature concerning the anatomy of medial soft-tissue stabilizers of the patella is growing exponentially. Much of the surgical literature has focused on the role of the medial patellofemoral ligament (MPFL) and techniques to reconstruct it, yet our understanding of its anatomy has evolved during the past several years. Given this, we report on the current understanding of medial patellofemoral anatomy and implications for reconstruction. METHODS: Current and historical studies of medial patellar anatomy were reviewed, which include the MPFL and medial quadriceps tendon femoral ligament (MQTFL), as well as that of the distal medial patellar restraints, the medial patellotibial ligament (MPTL) and medial patellomeniscal ligament (MPML). In addition to the reported findings, the authors' anatomic descriptions of each ligament during their dissections were identified and recorded. RESULTS: Despite the name of the MPFL, which implies that the ligament courses between the femur and patella, recent studies have highlighted the proximal MPFL fibers that attach to the quadriceps tendon, known as the MQTFL. The MPFL and MQTFL have also been referred to as the medial patellofemoral complex, reflecting the variability in anatomical attachment sites. The MPFL accounts for only half of the total restraint to lateral patellar displacement, and the remaining contributions to patellar stability are derived from the combination of the MPTL and MPML, which function primarily in greater degrees of knee flexion. CONCLUSION: The understanding of the complexity of the medial patellar stabilizers continues to evolve. Although MPFL reconstruction is gaining wide acceptance as a procedure to treat patellar instability, it is important to recognize the complex and changing understanding of the anatomy of the medial soft-tissue stabilizers and the implications for reconstruction. LEVEL OF EVIDENCE: V.

Patellar Instability Management: A Survey of the International Patellofemoral Study Group.

BACKGROUND: Although patellofemoral instability is among the most prevalent knee disorders, the management of patients with this condition is complex and remains variable, given the lack of long-term, high-level clinical outcome studies to compare various operative and nonoperative modalities. PURPOSE: To discover a consensus within treatment controversies in patellofemoral instability among experienced knee surgeons with a specific interest in the patellofemoral joint. STUDY DESIGN: Expert opinion; Level of evidence, 5. METHODS: A 3-step modified Delphi technique was used to establish a consensus. A 34-question, case-based online survey regarding patellofemoral instability was distributed to all active members of the International Patellofemoral Study Group. Consensus statements were generated if at least 66% of the respondents agreed and then redistributed to the same panel. Modifications to the consensus statements were made based on the iterative feedback process until no discordance was encountered in the third stage. RESULTS: Eight consensus statements were achieved. Nonoperative management is the current standard of care for a first-time dislocation in the absence of an osteochondral fragment or loose body requiring excision (100% agreement). In patients with a first-time dislocation with an operative osteochondral fracture requiring excision or repair, patellar instability should be addressed concurrently (89% agreement). Recurrent instability should be treated surgically, with most surgeons favoring medial reconstruction (77%-86% agreement). While there is general agreement that bony procedures should be performed to correct underlying bony deformities, there is no consensus regarding the most appropriate type of procedure performed. Lateral release should not be performed in isolation for the treatment of patellar instability (89% agreement). CONCLUSION: Despite the consensus generated in this study, our current understanding remains limited by a lack of high-level evidence as well as the numerous complex variables influencing treatment decision making. High-quality, multicenter randomized controlled trials, particularly those directly comparing specific surgical treatment methods while controlling for underlying risk factors, are needed to address these areas of uncertainty.

Patellofemoral Pain: An Enigma Explained by Homeostasis and Common Sense.

We present a rational, scientific, low-risk approach to patellofemoral pain (anterior knee pain) based on an understanding of tissue homeostasis. Loss of tissue homeostasis from overload and/or injury produces pain. Bone overload and synovial inflammation are common sources of such pain. Chondromalacia and malalignment are findings that almost always do not need to be "corrected" to relieve pain. Patience and persistence in nonoperative care results in consistent success. Surgery should be rare and done only after extensive nonoperative management and in the setting of clearly defined pathology. Rational surgical treatment is explained in the context of restoring tissue homeostasis to relieve pain.

The intra- and inter-observer reliability of the physical examination methods used to assess patients with patellofemoral joint instability.

BACKGROUND: An accurate physical examination of patients with patellar instability is an important aspect of the diagnosis and treatment. While previous studies have assessed the diagnostic accuracy of such physical examination tests, little has been undertaken to assess the inter- and intra-tester reliability of such techniques. The purpose of this study was to determine the inter- and intra-tester reliability of the physical examination tests used for patients with patellar instability. METHODS: Five patients (10 knees) with bilateral recurrent patellar instability were assessed by five members of the International Patellofemoral Study Group. Each surgeon assessed each patient twice using 18 reported physical examination tests. The inter- and intra-observer reliability was assessed using weighted Kappa statistics with 95% confidence intervals. RESULTS: The findings of the study suggested that there were very poor inter-observer reliability for the majority of the physical tests, with only the assessments of patellofemoral crepitus, foot arch position and the J-sign presenting with fair to moderate agreement respectively. The intra-observer reliability indicated largely moderate to substantial agreement between the first and second tests performed by each assessor, with the greatest agreement seen for the assessment of tibial torsion, popliteal angle and the Bassett's sign. CONCLUSIONS: For the common physical examination tests used in the management of patients with patellar instability inter-observer reliability is poor, while intra-observer reliability is moderate. Standardization of physical exam assessments and further study of these results among different clinicians and more divergent patient groups is indicated.

The female knee: anatomic variations and the female-specific total knee design.

UNLABELLED: The concept and need for a gender-specific or female-specific total knee prosthesis have generated interest and discussion in the orthopaedic community and the general public. This concept relies on the assumption of a need for such a design and the opinion that there are major anatomic differences between male and female knees. Most of the information regarding this subject has been disseminated through print and Internet advertisements, and through direct-to-patient television and magazine promotions. These sources and a recent article in a peer-reviewed journal, which support the need for a female-specific implant design, have proposed three gender-based anatomic differences: (1) an increased Q angle, (2) less prominence of the anterior medial and anterior lateral femoral condyles, and (3) reduced medial-lateral to anterior-posterior femoral condylar aspect ratio. We examined the peer-reviewed literature to determine whether women have had worse results than men after traditional TKAs. We found women have equal or better results than men. In addition, we reviewed the evidence presented to support these three anatomic differences. We conclude the first two proposed differences do not exist, and the third is so small that it likely has no clinical effect. LEVEL OF EVIDENCE: Level IV, systematic review. See the Guidelines for Authors for a complete description of levels of evidence.

Anterior knee pain: diagnosis and treatment.

Anterior knee pain is a frequent clinical problem. It provides a common challenge to diagnose and manage. Basic science studies have provided insight into the origin of anterior knee pain and refined understanding of the anatomy. Clinical evaluation has progressively focused on the contribution of the entire lower extremity to patellofemoral function. Nonsurgical management has been refined by the concept of the "envelope of function" and by increased understanding of the neuromuscular control of the knee. Indications for lateral release have been clarified and narrowed. Although anteromedial transfer of the tibial tuberosity is helpful in certain circumstances, reports of postoperative fracture have led to less aggressive rehabilitation protocols. Chondral resurfacing of the patellofemoral joint and patellofemoral arthroplasty are evolving. Emphasis should remain on nonsurgical management, which is sufficient in most patients.

Patellofemoral pain: results of nonoperative treatment.

Nonoperative treatment of patellofemoral pain has a long-standing tradition of success. I will discuss the scientific background and practical application of such treatment. Evaluation and treatment should include lower extremity flexibility, muscular control, and careful evaluation of tender structures. Avoiding pain during rehabilitation is important and suggestions for this are included in this review. Emphasis on accurate diagnosis, careful clinical evaluation, activity modification, flexibility, and strengthening in creating an effective program are discussed and the literature is reviewed. Most patients should go thorough nonoperative treatment before elective surgery for patellofemoral pain is prescribed.

The impact of schools self-administering substance abuse surveys: an evaluation.

The literature suggests that administering drug surveys to public school students is best done by persons outside of the school system (or at least unfamiliar to the students). This is the approach used by the long-time Monitoring the Future project. Because of the increased costs that administration by outside research associates requires (both time and transportation), we decided to design an experiment that would compare it to administration by school personnel. Six school systems were split, and 3756 surveys were administered, about half by outside research associates and half by school personnel. The results indicate that there were minimal and non-significant differences between the two groups. On the basis of these results, we draw the conclusion that school personnel are able to administer survey instruments without affecting the quality of the results and, thus, that school districts may safely use such data in the evaluation of their drug education and drug prevention programs.

Lateral retinacular release: a survey of the International Patellofemoral Study Group.

PURPOSE: The purpose of this investigation was to determine current views regarding lateral release among experienced knee surgeons with a specific interest in the patellofemoral joint. TYPE OF STUDY: Scientific survey. METHODS: A questionnaire was developed and mailed to all members of an international group with a specific interest in disorders of the patellofemoral joint. Frequencies and percentages of responses were calculated for each question to determine surgeon consensus. We measured agreement among responses using the kappa statistic. This provided an indication of consistency for each question as well as correlation among the responses to different questions. RESULTS: The survey response rate was 60%. Isolated lateral release was estimated to account for only 1 to 5 surgical cases per respondent per year, or 2% of cases performed annually. In the setting of arthroscopy or exploration, 74% of respondents believed that lateral release calls for specific informed consent. Strong consensus was found that objective evidence is needed to justify lateral release, but agreement was poor as to what clinical evidence provides the most appropriate indication for the procedure. CONCLUSIONS: Even among experienced knee surgeons with a special interest in diseases of the patellofemoral articulation, isolated lateral release is rarely performed. Strong consensus was found that isolated lateral release should not be undertaken without prior planning in the form of objective clinical indications and preoperative informed consent. LEVEL OF EVIDENCE: Level V.

Patellofemoral malalignment: looking beyond the viewbox.

A clear understanding of the pathophysiology of anterior knee pain is inhibited by the use of imprecise, poorly defined, and often interchanged words, such as malalignment, patellar alignment, maltracking, subluxation, dislocation, and congruence. The literature is filled with articles regarding the diagnosis, "malalignment of the patella," most of which give no precise diagnosis. This article presents a definition of malalignment and a plea for rational descriptive and scientific analysis. Much of what is described is based on theory, not facts. These ideas are supported by clinical experience and logical analysis, but very little in the way of scientific data. Most of the data involve radiographic images, which present only one piece of the puzzle.

Neurovascular risk of bicortical tibial drilling for screw and spiked washer fixation of soft-tissue anterior cruciate ligament graft.

PURPOSE: As the use of soft-tissue anterior cruciate ligament (ACL) grafts, including hamstring grafts, has become more prominent and the benefits of aggressive rehabilitation have become clear, maximizing fixation with screw and spiked washers is important. Bicortical fixation may be superior. We were concerned about potential neurovascular risks and designed this study to define the posterior neurovasculature structures at risk when drilling for bicortical tibial screw fixation during ACL reconstruction. Type of Study: Consecutive sample. METHODS: We placed the tibial tunnel arthroscopically in 10 cadaveric knees using a standard tibial drill guide. Accurate tibial tunnel position was documented in each knee by lateral radiograph. A 4.5-mm bicortical drill hole was placed perpendicular to the tibial surface 1 cm distal to the tibial tunnel. The distances from the posterior tibial drill exit point to nearby neurovascular structures were measured with a caliper. RESULTS: The closest structure to the exit point was the bifurcation of the popliteal artery/vein (11.4 +/- 0.6 mm; range, 8.4 to 14.0 mm). The next closest was the anterior tibial vein (11.7 +/- 1.6 mm; range, 3.5 to 22.8 mm). The closest any individual hole came to a neurovascular structure was 3.5 mm from the anterior tibial vein. CONCLUSIONS: Bicortical drilling for fixation of soft tissue grafts appears reasonably safe. The structures at greatest risk for injury are the bifurcation of the popliteal artery/vein and the anterior tibial vein.