A systematic review of clinical outcomes of pedicled flap repairs of the knee extensor mechanism.

Background Rupture of the extensor mechanism of the knee has severe functional morbidity, and repair can be complicated by infection, allograft degeneration, and recurrent rupture. Techniques of autologous tissue repair utilizing pedicled flaps such as the gastrocnemius offer vascularized methods of reconstruction, with potentially diminished complication rates. The goal of this study was to evaluate the functional outcomes and complications associated with pedicled flap repair of the knee extensor mechanism. Methods A systematic review was conducted following PRISMA guidelines. Publications that focused on local myocutaneous flaps as a means for reconstruction were included. Causes for knee extensor mechanism deficit, flap characteristics, ambulation rate, changes in range of motion pre- and post-operation, and postoperative complications were analyzed. Technique reports including primary suture repairs, synthetic mesh, and allograft use were excluded. Results An initial 119 studies were identified, with final review of 22 observational studies encompassing 128 cases of pedicled flap reconstructions. The gastrocnemius (88.2%, n=113), quadriceps (6.3%, n=8), and a combination of the vastus and gastrocnemius flaps (5.5%, n=7), were the most frequently utilized flaps. Functional outcomes were favorable with 87.2% of patients achieving ambulation without external support. Variability in range of motion outcomes across different flap may be secondary to the patient characteristics as well as extent of initial injury. Conclusions Autologous pedicle flap reconstruction of the knee extensor mechanism emerges as a viable option for cases characterized by extensive defects and insufficient soft tissue coverage, which are not amenable to direct suture repairs or allografts. Postoperative assessments revealed that the majority of patients experienced improved ambulation status, with no instances of deterioration noted among the patients.

The Continued Impact of Godina's Principles: Outcomes of Flap Coverage as a Function of Time After Definitive Fixation of Open Lower Extremity Fractures.

BACKGROUND: Early soft tissue coverage of open lower extremity fractures within 72 hours of injury leads to improved outcomes. Little is known about outcomes when definitive fixation is completed first. The purpose of this study is to quantify postoperative outcomes when soft tissue reconstruction is delayed until after definitive open reduction and internal fixation (ORIF) is completed. METHODS: An insurance claims database was queried for all patients with open lower extremity fractures between 2010 and 2020 who underwent free or axial flap reconstruction after ORIF. This cohort was stratified into three groups: reconstruction performed 0 to 3, 3 to 7, and 7+ days after ORIF. The primary outcome was 90-day complication and reoperation rates. Bivariate and multivariable regression of all-cause complications and reoperations was evaluated for time to flap as a risk factor. RESULTS: A total of 863 patients with open lower extremity fractures underwent ORIF prior to flap soft tissue reconstruction. In total, 145 (16.8%), 162 (18.8%), and 556 (64.4%) patients underwent soft tissue reconstruction 0 to 3 days, 4 to 7 days, and 7+ days after ORIF, respectively. The 90-day complication rate of surgical site infections ( SSI; 16.6%, 16,7%, 28.8%; p = 0.001) and acute osteomyelitis (5.5%, 6.2%, 27.7%; p < 0.001) increased with delayed soft tissue reconstruction. Irrigation and debridement rates were directly related to time from ORIF to flap (33.8%, 51.9%, 61.9%; p < 0.001). Hardware removal rates were significantly higher with delayed treatment (10.3%, 9.3%, 39.3%; p < 0.001). The 0 to 3 day (odds ratio [OR] = 0.22; 95% confidence interval [CI]: 0.15, 0.32) and 4 to 7 day (OR = 0.26; 95% CI: 0.17, 0.40) groups showed protective factors against all-cause complications after bivariate and multivariate regression. CONCLUSION: Early soft tissue reconstruction of open lower extremity fractures performed within 7 days of ORIF reduces complication rates and reduces the variability of complication rates including SSIs, acute osteomyelitis, and hardware failure.

Coordinating brain-distributed network activities in memory resistant to extinction.

Certain memories resist extinction to continue invigorating maladaptive actions. The robustness of these memories could depend on their widely distributed implementation across populations of neurons in multiple brain regions. However, how dispersed neuronal activities are collectively organized to underpin a persistent memory-guided behavior remains unknown. To investigate this, we simultaneously monitored the prefrontal cortex, nucleus accumbens, amygdala, hippocampus, and ventral tegmental area (VTA) of the mouse brain from initial recall to post-extinction renewal of a memory involving cocaine experience. We uncover a higher-order pattern of short-lived beta-frequency (15-25 Hz) activities that are transiently coordinated across these networks during memory retrieval. The output of a divergent pathway from upstream VTA glutamatergic neurons, paced by a slower (4-Hz) oscillation, actuates this multi-network beta-band coactivation; its closed-loop phase-informed suppression prevents renewal of cocaine-biased behavior. Binding brain-distributed neural activities in this temporally structured manner may constitute an organizational principle of robust memory expression.

Routine Histopathologic Examination of Bone Obtained During Elective Primary Total Knee Arthroplasty May Not Be Necessary.

Background: Many institutions require the routine collection of pathology samples from every primary total knee arthroplasty (TKA) performed. These policies are controversial, and their cost-effectiveness is difficult to define. We sought to judge the cost-effectiveness of one such policy according to World Health Organization recommendations. Methods: We analyzed 3200 consecutive primary TKAs, comparing our presumed preoperative diagnoses against the diagnoses made by the pathologist. Diagnoses were categorized as concordant (matching), discrepant (not matching but without impact to patient management), or discordant (not matching and resulting in a direct change to patient management). An incremental cost-utility ratio analysis was performed to determine the cost-effectiveness of our institution's policy to routinely collect pathology samples from every primary TKA performed. Cost-effectiveness was defined by World Health Organization guidelines as a cost of less than $228,090 per quality-adjusted life year gained. Results: Twelve pathology samples were lost before reaching a pathologist. From the remaining 3188 samples, we identified 3158 concordant cases, 29 discrepant diagnoses, and 1 discordant diagnosis. It cost an estimated $10,522.60 to identify each discrepant diagnosis and an estimated $305,155.36 to diagnose one discordant case in our cohort. Our incremental cost-utility ratio analysis revealed that we spent $305,155.36 to gain 0 quality-adjusted life years for our patients. Conclusions: Routine histopathologic analysis of TKA samples was cost-ineffective in our patient cohort and may not be necessary during routine TKA.

Technical Strategies for Harvest of the Subtotal Pedicled Fillet of Thigh Flap for Reconstruction of External Hemipelvectomy and Hemicorporectomy Defects.

External hemipelvectomy and hemicorporectomy have been described in the literature for a variety of indications. A commonly used reconstructive technique is the pedicled anterior subtotal fillet of thigh flap. However, there are few descriptions regarding the technical pearls of harvest and inset of this flap. Here, we describe our step-by-step technique, as performed in three patients. The flap is pedicled on the common femoral artery and extends longitudinally to the knee to achieve the length required to extend past the midline and resurface sacral pressure ulcers, which are commonly found in patients who undergo this procedure for refractory pelvic osteomyelitis. Additionally, we describe a potential salvage option with late division of the popliteal artery to preserve the option for free tissue transfer of a subtotal fillet of lower leg flap.

A multimodal intraosseous infusion of morphine and ketorolac decreases early postoperative pain and opioid consumption following total knee arthroplasty.

BACKGROUND: Multimodal pain management regimens and intraosseous infusion of morphine are two novel techniques that show promise in decreasing postoperative pain and opioid consumption following total knee arthroplasty. However, no study has analyzed the intraosseous infusion of a multimodal pain management regimen in this patient population. The purpose of our investigation was to examine the intraosseous administration of a multimodal pain regimen comprised of morphine and ketorolac during total knee arthroplasty with regard to immediate and 2-week postoperative pain, opioid pain medication intake, and nausea levels. METHODS: In this prospective cohort study with comparisons to a historical control group, 24 patients were prospectively enrolled to receive an intraosseous infusion of morphine and ketorolac dosed according to age-based protocols while undergoing total knee arthroplasty. Immediate and 2-week postoperative Visual Analog Score (VAS) pain scores, opioid pain medication intake, and nausea levels were recorded and compared against a historical control group that received an intraosseous infusion of morphine alone. RESULTS: During the first four postoperative hours, patients who received the multimodal intraosseous infusion experienced lower VAS pain scores and required less breakthrough intravenous pain medication than those patients in our historical control group. Following this immediate postoperative period, there were no additional differences between groups in terms of pain levels or opioid consumption, and there were no differences in nausea levels between groups at any time. CONCLUSIONS: Our multimodal intraosseous infusion of morphine and ketorolac dosed according to age-based protocols improved immediate postoperative pain levels and reduced opioid consumption in the immediate postoperative period for patients undergoing total knee arthroplasty.

Concepts in soft-tissue reconstruction of the contracted hand and upper extremity after burn injury.

Burns and their subsequent contracture result in devastating functional and aesthetic consequences which disproportionally affect the upper extremity. By focusing on reconstruction with analogous tissue and utilizing the reconstructive elevator, function can be restored concomitantly with form and aesthetic appearance. General concepts for soft-tissue reconstruction after burn contracture are presented for different sub-units and joints.

Stable, interactive modulation of neuronal oscillations produced through brain-machine equilibrium.

Closed-loop interaction has the potential to regulate ongoing brain activity by continuously binding an external stimulation to specific dynamics of a neural circuit. Achieving interactive modulation requires a stable brain-machine feedback loop. Here, we demonstrate that it is possible to maintain oscillatory brain activity in a desired state by delivering stimulation accurately aligned with the timing of each cycle. We develop a fast algorithm that responds on a cycle-by-cycle basis to stimulate basal ganglia nuclei at predetermined phases of successive cortical beta cycles in parkinsonian rats. Using this approach, an equilibrium emerges between the modified brain signal and feedback-dependent stimulation pattern, leading to sustained amplification or suppression of the oscillation depending on the phase targeted. Beta amplification slows movement speed by biasing the animal's mode of locomotion. Together, these findings show that highly responsive, phase-dependent stimulation can achieve a stable brain-machine interaction that leads to robust modulation of ongoing behavior.

Digital ischemia after lidocaine with epinephrine injection in a patient with primary Raynaud's phenomena.

Lidocaine with epinephrine is ubiquitous in hand procedures. Although existing literature supports the overall safety of this, significant physiologic changes accompanying epinephrine can disproportionately affect vascularly compromised patients, such as in Raynaud's phenomenon. The literature is reviewed and a case presented regarding the dangers of epinephrine injection in this population.

Time-Driven Activity-Based Costing in Preoperative Tasks for Total Hip and Knee Arthroplasty.

BACKGROUND: Substantial work in the preoperative phase of total hip arthroplasty (THA) and total knee arthroplasty (TKA) is unaccounted for in current Relative Value Scale Update Committee methodology. A Time-Driven Activity-Based Costing (TDABC) analysis allows for an accurate assessment of the preoperative costs associated with total joint replacement surgery. METHODS: The mean time that clinical staff members spent on preoperative tasks per patient was multiplied by the hourly salary. Clinical staff members included orthopedic surgeons, nurse practitioners or physician assistants, nurses, medical assistants, and surgical coordinators. Mean time spent on preoperative tasks was obtained from the most recent literature. Salaries were obtained from the nationwide database provided by Glassdoor Inc. RESULTS: Total time spent among clinical staff involved in preoperative tasks for each arthroplasty patient was 8.45 hours (2.96-13.94). Total TDABC was calculated to be $348.17 (132.46-562.64). Accounting for preoperative tasks, the TDABC for TKA/THA increases from $13321.5 to $13669.67. Preoperative tasks are composed of 2.6% of total TKA/THA TDABC. In 2020, an estimated $544,189,710 of preoperative TKA/THA work was completed. CONCLUSION: Surgeons, providers, and ancillary staff involved in THA/TKA spend a cumulative preoperative work time of approximately 8.5 hours per patient, which equates to $348.17 that is currently unaccounted for in Relative Value Scale Update Committee methodology.

Parkinson's disease uncovers an underlying sensitivity of subthalamic nucleus neurons to beta-frequency cortical input in vivo.

Abnormally sustained beta-frequency synchronisation between the motor cortex and subthalamic nucleus (STN) is associated with motor symptoms in Parkinson's disease (PD). It is currently unclear whether STN neurons have a preference for beta-frequency input (12-35 Hz), rather than cortical input at other frequencies, and how such a preference would arise following dopamine depletion. To address this question, we combined analysis of cortical and STN recordings from awake human PD patients undergoing deep brain stimulation surgery with recordings of identified STN neurons in anaesthetised rats. In these patients, we demonstrate that a subset of putative STN neurons is strongly and selectively sensitive to magnitude fluctuations of cortical beta oscillations over time, linearly increasing their phase-locking strength with respect to the full range of instantaneous amplitude in the beta-frequency range. In rats, we probed the frequency response of STN neurons in the cortico-basal-ganglia-network more precisely, by recording spikes evoked by short bursts of cortical stimulation with variable frequency (4-40 Hz) and constant amplitude. In both healthy and dopamine-depleted rats, only beta-frequency stimulation led to a progressive reduction in the variability of spike timing through the stimulation train. This suggests, that the interval of beta-frequency input provides an optimal window for eliciting the next spike with high fidelity. We hypothesize, that abnormal activation of the indirect pathway, via dopamine depletion and/or cortical stimulation, could trigger an underlying sensitivity of the STN microcircuit to beta-frequency input.

A Systematic Review and Analysis of Palmer Type I Triangular Fibrocartilage Complex Injuries: Outcomes of Treatment.

Triangular fibrocartilage complex (TFCC) injuries can present incidentally as an asymptomatic lesion or can cause acute and chronic pain. This study compared different treatment approaches for symptomatic Palmer Type 1 TFCC injuries and rates of improvement using a systematic review of the literature. Two hundred thirty-one articles were identified, 43 met criteria and were included. Two of these articles indicated conservative therapy may be adequate. Patients who underwent debridement for any Type 1 Palmer class returned to work at a rate of 92% ( n = 182), but only 44% ( n = 38) were free of pain. For 1B lesions that underwent repair, 68.3% ( n = 226) were able to return to work and 41% ( n = 52) had persistent pain. 1D lesions were treated with both repair and debridement with similar results. Data for Types 1A and 1C were limited as no authors solely addressed these lesions. For 1A lesions, those treated with traditional treatment of debridement still had high rates of being unable to return to work. The literature remains insufficient, making comparison between studies and techniques difficult. For asymptomatic injuries, there is no need for treatment. For patients with recalcitrant symptoms, surgery improves pain, grip strength, and increases return to work and activity. The level of evidence is IV.

Targeted Muscle Reinnervation: Outcomes in Treating Chronic Pain Secondary to Extremity Amputation and Phantom Limb Syndrome.

BACKGROUND: Secondary to vascular disease, oncological resection, or devastating trauma, lower extremity amputations are performed globally at a yearly rate exceeding 1 million patients. Three-quarters of these patients will develop chronic pain or phantom pain, which presents a functional limitation for prosthetic use and contributes to deconditioning and increased mortality. Targeted muscle reinnervation (TMR) presents a surgical solution to this problem as either a primary or secondary intervention. METHODS: A review of the existing literature was conducted using a combination of the terms "phantom pain" "chronic pain," "neuroma," and "targeted muscle reinnervation" in Medline and PubMed. RESULTS: Five articles were found which addressed TMR for pain syndromes, four of which involved lower extremity amputation. Four of the articles were retrospective reviews, and one was a randomized control trial. A total of 149 patients were included, of which 82 underwent lower extremity amputation. Ninety-two of the patients underwent prophylactic TMR, of which 57 were secondary procedures.In patients who underwent TMR at the time of amputation, all studies reported a minimal development of symptomatic neuromas (27%). For secondary TMR, near-complete resolution of previous pain was found (90%). Phantom pain was noted to be similar to other studies in the literature but noted to improve over time with both primary (average drop of 3.5 out of 10 points on the numerical rating scale) and secondary (diminishing from 72% of patients to 13% over 6 months) operations. CONCLUSION: Although much of the current literature is limited to retrospective studies with few patients, these data point toward near-complete resolution of neuroma pain after treatment as well as complete prevention of chronic pain if TMR is used as a prophylactic measure during the index amputation. THIS STUDY WAS A LEVEL OF EVIDENCE IV: .

MRI Evaluation of Posterior Capsular Dehiscence After Posterior Approach Total Hip Arthroplasty.

INTRODUCTION: To our knowledge, no previous study has evaluated the use of MRI to diagnose posterior capsule dehiscence after posterior approach total hip arthroplasty (THA) with capsular repair and its association with postoperative posterior hip dislocation. METHODS: A retrospective chart review of patients who underwent posterior approach THA with capsulotomy repair was performed. Patients were identified who subsequently underwent MRI, and these studies were evaluated for signs of posterior capsular disruption. Each chart was then evaluated for episodes of postoperative hip dislocation. RESULTS: Six hundred seventy-five patients were included in the retrospective review. Thirty-two patients (17 women [aged 37 to 78 years] and 15 men [aged 34 to 80 years]) met the inclusion criteria. Fifteen patients of 32 (48.4%) developed posterior capsule dehiscence after repair (group 1). Seventeen patients of 32 (51.6%) did not have MRI evidence of posterior capsule dehiscence (group 2). In group 1, 2 patients of 15 (13.3%) experienced a posterior hip dislocation. No group 2 patients experienced a posterior hip dislocation. Overall, only 2 patients of 32 (6.3%) developed posterior hip dislocations. In group 1, 12 patients of 15 (80%) developed dehiscence at the lateral capsule margin at the greater trochanter suture repair site. The two patients in group 1 with posterior hip dislocations displayed MRI evidence of capsular dehiscence in this region. Two patients of 15 (13.3%) in group 1 demonstrated dehiscence at the central third of the posterior capsule, whereas 1 patient of 15 (6.6%) in group 1 demonstrated dehiscence at the medial/acetabular margin. No significant difference was found between the dislocation rates between groups 1 and 2 (P = 0.212). The distribution of capsular dehiscence (lateral, middle, and medial capsule) in group 1 was significant (P = 0.0006). DISCUSSION: MRI can effectively diagnose capsular dehiscence in patients who have undergone posterior THA. Most repaired capsules failed in the lateral repair region. MRI offers the potential to identify patients with a higher risk of implant dislocation. LEVEL OF EVIDENCE: Therapeutic level III.

Novelty and Dopaminergic Modulation of Memory Persistence: A Tale of Two Systems.

Adaptation to the ever-changing world is critical for survival, and our brains are particularly tuned to remember events that differ from previous experiences. Novel experiences induce dopamine release in the hippocampus, a process which promotes memory persistence. While axons from the ventral tegmental area (VTA) were generally thought to be the exclusive source of hippocampal dopamine, recent studies have demonstrated that noradrenergic neurons in the locus coeruleus (LC) corelease noradrenaline and dopamine in the hippocampus and that their dopamine release boosts memory retention as well. In this opinion article, we propose that the projections originating from the VTA and the LC belong to two distinct systems that enhance memory of novel events. Novel experiences that share some commonality with past ones ('common novelty') activate the VTA and promote semantic memory formation via systems memory consolidation. By contrast, experiences that bear only a minimal relationship to past experiences ('distinct novelty') activate the LC to trigger strong initial memory consolidation in the hippocampus, resulting in vivid and long-lasting episodic memories.

Phase-Dependent Suppression of Beta Oscillations in Parkinson's Disease Patients.

Synchronized oscillations within and between brain areas facilitate normal processing, but are often amplified in disease. A prominent example is the abnormally sustained beta-frequency (∼20 Hz) oscillations recorded from the cortex and subthalamic nucleus of Parkinson's disease patients. Computational modeling suggests that the amplitude of such oscillations could be modulated by applying stimulation at a specific phase. Such a strategy would allow selective targeting of the oscillation, with relatively little effect on other activity parameters. Here, activity was recorded from 10 awake, parkinsonian patients (6 male, 4 female human subjects) undergoing functional neurosurgery. We demonstrate that stimulation arriving on a particular patient-specific phase of the beta oscillation over consecutive cycles could suppress the amplitude of this pathophysiological activity by up to 40%, while amplification effects were relatively weak. Suppressive effects were accompanied by a reduction in the rhythmic output of subthalamic nucleus (STN) neurons and synchronization with the mesial cortex. While stimulation could alter the spiking pattern of STN neurons, there was no net effect on firing rate, suggesting that reduced beta synchrony was a result of alterations to the relative timing of spiking activity, rather than an overall change in excitability. Together, these results identify a novel intrinsic property of cortico-basal ganglia synchrony that suggests the phase of ongoing neural oscillations could be a viable and effective control signal for the treatment of Parkinson's disease. This work has potential implications for other brain diseases with exaggerated neuronal synchronization and for probing the function of rhythmic activity in the healthy brain.SIGNIFICANCE STATEMENT In Parkinson's disease (PD), movement impairment is correlated with exaggerated beta frequency oscillations in the cerebral cortex and subthalamic nucleus (STN). Using a novel method of stimulation in PD patients undergoing neurosurgery, we demonstrate that STN beta oscillations can be suppressed when consecutive electrical pulses arrive at a specific phase of the oscillation. This effect is likely because of interrupting the timing of neuronal activity rather than excitability, as stimulation altered the firing pattern of STN spiking without changing overall rate. These findings show the potential of oscillation phase as an input for "closed-loop" stimulation, which could provide a valuable neuromodulation strategy for the treatment of brain disorders and for elucidating the role of neuronal oscillations in the healthy brain.

Blood Loss Reduction with Tranexamic Acid and a Bipolar Sealer in Direct Anterior Total Hip Arthroplasty.

The purpose of this study is to determine the effectiveness of tranexamic acid (TXA) alone and in conjunction with a bipolar sealer in reducing postoperative transfusions during direct anterior (DA) total hip arthroplasty (THA).In this retrospective review, we analyzed 173 consecutive patients who underwent primary unilateral DA THA performed by 2 surgeons during a 1-year period. Subjects were divided into 3 groups based on TXA use: 63 patients received TXA alone (TXA group), 49 patients received TXA in addition to a bipolar sealer (TXA + bipolar sealer group), and 61 patients received neither TXA nor a bipolar sealer (control group). Primary end points were the transfusion rate and estimated blood loss. Secondary end points were length of stay, postoperative drop in hemoglobin, and postoperative drain output. Two patients in the TXA group and 10 patients in the control group were transfused (P = .02). In the TXA + bipolar sealer group, 1 patient was transfused (P = .02). No significant difference in the rate of transfusion was found between the TXA group and the TXA + bipolar sealer group (P = .99). Estimated blood loss was 310.3 mL ± 182.5 mL in the TXA group (P = .004), 292.9 mL ± 130.8 mL in the TXA + bipolar sealer group (P = .003), and 404.9 mL ± 201.2 mL in the control group. The use of TXA, with and without the concomitant use of a bipolar sealer, decreases intraoperative blood loss and postoperative transfusion requirements. The addition of a bipolar sealer, however, does not appear to provide any additional decrease in blood loss.

Effectiveness of Novel Adjuncts in Pain Management Following Total Knee Arthroplasty: A Randomized Clinical Trial.

BACKGROUND: Total knee arthroplasty (TKA) can be associated with significant pain which can negatively impact outcomes. Multiple strategies have been employed to reduce pain. The aim of this study is to compare the effectiveness of 3 different pain management modalities after TKA that included (1) our standardized knee injection cocktail and oral acetaminophen, (2) liposomal bupivacaine periarticular injection and oral acetaminophen, and (3) our standardized knee injection cocktail and intravenous (IV) acetaminophen. METHODS: A prospective randomized clinical trial was conducted with 3 perioperative pain management regimes: oral acetaminophen and our standardized knee injection cocktail (standard group), oral acetaminophen and liposomal bupivacaine periarticular injection (LB group), and IV acetaminophen and our standardized knee injection cocktail (IVA group). Primary outcome measures included visual analog scale, total morphine equivalents, and the opioid-related symptoms distress scale at 24 and 48 hours postoperatively. RESULTS: There were no significant differences on visual analog scale/opioid-related symptoms distress scale scores 24 hours after surgery. The LB group required significantly more narcotics (total morphine equivalents) than the standard (P = .025) and IVA groups (P = .032). No significant differences were observed on any of the outcomes measured at 48 hours after surgery. CONCLUSION: Our data suggest that there is no added benefit in the routine use of IV acetaminophen or liposomal bupivacaine after TKA.

Anthropometric Measurements of Knee Joints in the Hispanic Population.

BACKGROUND: Total knee arthroplasty (TKA) systems provide a set of incrementally sized tibial and femoral components intended to accommodate most knee parameters. However, the most commonly used systems in the United States were developed using data from Caucasian patients which might not lead to the best fit in non-Caucasians. Therefore, we wanted to evaluate whether these TKA systems proportionally match femoral and tibial measurements in Hispanics. METHODS: All lower extremity magnetic resonance imaging performed at our institution between January 2007 and October 2015 were screened. A total of 500 nonarthritic knees from the same number of Hispanic patients were included in this retrospective descriptive radiographic study. Intraoperative osseous TKA resections were simulated on magnetic resonance imaging. Linear regression analyses were used to contrast the mediolateral (ML) width/anteroposterior (AP) length of simulated resected femoral condyle and tibia with the ML/AP dimensions of components offered by 4 current TKA systems. RESULTS: Simulated resected male femurs tended to be wider than most TKA system components for a given AP size, probably leading to component ML underhang. Altogether, systems studied accommodated most AP and ML measurements of female condyles. However, we identified subsets of Hispanic female patients with certain AP lengths and/or ML widths that particular knee systems could not accommodate. Resected male and female tibias tended to be slightly narrower than all TKA systems for a given AP size. CONCLUSION: The results of our study provide valuable data concerning the unique morphology of the Hispanic knee. These data can assist surgeons in the selection of the most suitable TKA systems for these patients.