Limb Rotation in Lower Extremity Fractures.

Fractures of the tibia and femur are common. Rotation of the limb can affect the outcome of the injury, both in the immediate term and the long term. Because plain radiographs are two dimensional, rotation is hard to assess radiographically. As a result, rotational malalignment is common. It is important to provide technical tips on the assessment of rotation preoperatively, intraoperatively, and postoperatively. The goal is to better assess rotation so that deformity can be minimized. This applies to fractures of the tibia and femur. Even after careful treatment, rotational deformities can occur. When they are symptomatic, correction should be considered. Techniques for correction of malrotation of both tibial and femoral fractures are presented.

Traumaplasty: When and How to Perform Acute Arthroplasty for Fractures Around the Hip in the Elderly Patient.

Acute fractures around the hip are prevalent injuries associated with potentially devastating outcomes. The growing utilization of arthroplasty for femoral neck fractures in the elderly is likely a result of improvements in reoperation rates and postoperative function. Compared to hemiarthroplasty, total hip arthroplasty is associated with a slight functional benefit that is unlikely noticeable for many patients, as well as minimal differences in complications and patient reported outcome measures. However, the evidence supporting cement use in femoral stem fixation is robust. Multiple high power randomized controlled trial-based studies indicate cement fixation brings more predictable outcomes and fewer reoperations. In the setting of acute acetabular fracture, total hip arthroplasty is a favorable approach for elderly patients and fracture patterns associated with increased risk of revision after open reduction and internal fixation. Variations in patient characteristics and fracture patterns demand careful consideration whenever selecting the optimal treatment. In fracture patient populations, comanagement is an important consideration when seeking to reduce complications and promote cost-effective quality care.

Go Big or Go Home: Obesity and Total Joint Arthroplasty.

Obesity is highly prevalent, and it is expected to grow considerably in the United States. The association between obesity and an increased risk of complications following total joint arthroplasty (TJA) is widely accepted. Many believe that patients with body mass index (BMI) >40 have complications rates that may outweigh the benefits of surgery and should consider delaying it. However, the current literature on obesity and outcomes following TJA is observational, very heterogeneous, and full of confounding variables. BMI in isolation has several flaws and recent literature suggests shifting from an exclusively BMI <40 cutoff to considering 5 to 10% preoperative weight loss. BMI cutoffs to TJA may also restrict access to care to our most vulnerable, marginalized populations. Moreover, only roughly 20% of patients instructed to lose weight for surgery are successful and the practice of demanding mandatory weight loss needs to be reconsidered until convincing evidence exists that supports risk reduction as a result of preoperative weight loss. Obese patients can benefit greatly from this life-changing procedure. When addressing the potential difficulties and by optimizing preoperative assessment and intraoperative management, the surgery can be conducted safely. A multidisciplinary patient-centered approach with patient engagement, shared decision-making, and informed consent is recommended.

Outcomes of Nonoperatively Treated Vancouver B1 Fractures: Is Failure Common?

BACKGROUND: Periprosthetic fractures (PPFx) are a severe complication of total hip and hemiarthroplasty. Surgical treatment is typically performed but can result in major morbidity. Nonoperative PPFx management may provide a successful treatment alternative in select patients. METHODS: Vancouver B1 PPFx patients treated over a 10-year period were identified. Patient demographic data were retrospectively recorded. Injury and postoperative radiographs were reviewed. There were 48 patients who met the study criteria. Patients were divided into operative and nonoperative comparative cohorts. Outcome comparisons between the 2 cohorts included 1-year mortality, unplanned surgery within 24 months of injury, fracture union rate, and return to preinjury ambulation status. RESULTS: There was no difference in 1-year mortality between the nonoperative and operative cohorts (17 versus 8%; P = .32). We found no significant difference in unplanned surgery between the nonoperative and operative groups (8.7 versus 12%; P = .71), fracture union (100 versus 96%, P = .34), or return to ambulation status (86 versus 91%; P = .86). Nonoperative fractures were minimally displaced and within the metaphyseal region of the proximal femur without stem subsidence. Nonoperative fractures with subsequent treatment failure had initial fracture extension closer to the tip of the stem compared to successfully treated nonoperative fractures (5.5 versus 10.2 centimeters; P = .02). CONCLUSION: Select nonoperatively treated patients had infrequent need for unplanned surgery, high union rate, and return to their preinjury ambulation status. Nonoperative management is not appropriate for all Vancouver B1 PPFx, but those patients who have minimally displaced meta-diaphyseal fractures and partial remaining distal fixation can be successfully treated.

Common Practices in Intra-Articular Corticosteroid Injection for the Treatment of Knee Osteoarthritis: A Survey of the American Association of Hip and Knee Surgeons Membership.

BACKGROUND: Knee osteoarthritis nonoperative management options remain limited. Our aim is to define the current American Association of Hip and Knee Surgeons (AAHKS) members' practices and perceptions in terms of the frequency, formulation, use of concomitant aspiration, maximum lifetime number of injections, efficacy, interval between injection and surgery and complication rates. METHODS: A 22-question survey based on Likert scale response anchors was approved and distributed by the AAHKS Research Committee to its membership by email during the Spring 2019 meeting. Data were managed with REDCap software. RESULTS: Membership response totaled 537 of 2365 (22.7%) members. Highlights include every respondent using intra-articular corticosteroid injections (ICIs) in their practice, and most use a three-month minimum interval, although the preferred interval is longer. Near consensus was found waiting three months before surgery. There was a great variability in the number of injections allowed, and injections before surgery were very common. Nearly all responders use a local anesthetic mixture with the cortisone injection, but there was great variation in corticosteroid type: methylprednisolone (42%), triamcinolone (41%), betamethasone (13.3%), and dexamethasone (3.7%). CONCLUSION: The results of our survey indicate the majority of the AAHKS members who completed the survey use ICIs routinely for treatment of knee osteoarthritis. There was near consensus in ICIs, which is effective with decreasing efficacy over serial injections, and an absolute minimum interval between injections was believed by most to be three months with no clearly defined lifetime limit and strong consensus for a three-month preoperative interval. The formulation of steroid, local anesthetic, and skin preparation technique varied greatly.

A Poster Summarizing the American Academy of Orthopaedic Surgeons Knee Osteoarthritis Clinical Practice Guideline Is a Powerful Tool for Patient Education: A Randomized Controlled Trial.

BACKGROUND: In 2013, the American Academy of Orthopaedic Surgeons (AAOS) published an evidence-based clinical practice guideline (CPG) on conservative treatment options for patients with knee osteoarthritis (OA). The purpose of this study is to evaluate the effectiveness of a poster outlining the AAOS knee OA CPG on patient comprehension and satisfaction in the clinic. METHODS: This is a prospective 2-armed randomized controlled trial. Patients were eligible if they were of age 40-85 years, had degenerative knee OA, and did not consent for surgery. Patients were randomized to nonposter (standard care) and poster rooms. Knee OA treatment options were described to the patient verbally and posters were used as a teaching tool when present. The main outcomes were comprehension and satisfaction scores on a survey. RESULTS: Of the 105 patients enrolled, 51 (48.6%) were randomized to usual care (control) and 54 (51.4%) to the intervention (poster). Poster patients outperformed control patients with an average of 55.3% ± 16.7% (mean ± SD) compared to 39.5% ± 13.3% correct answers (P < .001). And 66.7% of poster patients and 29.4% of control patients achieved an adequately informed status of >50% correct answers (P < .001; 50.5% overall). With a maximum possible score of 10, visit satisfaction scores were 9.4 ± 1.0 in poster patients and 9.2 ± 1.7 in control patients (P = .50). CONCLUSION: Patients educated using an AAOS knee CPG poster showed significant improvements in knowledge and were more likely to achieve an adequately informed status. No difference existed in visit satisfaction. A poster offers a low-cost, effective educational tool. LEVEL OF EVIDENCE: Level 1.

MRI-only occult geriatric hip fractures: is displacement common with nonoperative treatment?

INTRODUCTION: Although surgical fixation is routinely recommended for geriatric hip fractures, nonoperative treatment may be an option for certain stable fracture patterns. Occult hip fractures are nondisplaced fractures not evident on radiographs, but display intraosseous edema on MRI. Our aim is to report the rate of nonoperative treatment failure in patients with occult geriatric hip fractures. METHODS: All nonoperatively treated femoral neck or intertrochanteric femur fractures (AO/OTA 31A and 31B) from 2003 to 2018 were identified. Patients older than 65 years with negative radiographs but a hip fracture evident on MRI were included. Patients who died prior to fracture displacement or union were excluded. Charts and imaging were reviewed for demographic data, fracture type, clinical course, displacement, and whether corrective surgery was performed. RESULTS: Of 15 final study patients, there were 6 femoral neck and 9 intertrochanteric fractures. Two fractures displaced, both requiring surgery (2/15; 13.3%). Both displacements occurred in the femoral neck group (2/6; 33%) compared to none in the intertrochanteric cohort (0/9; 0%). This trend did not reach statistical significance (p = 0.14). CONCLUSION: Thirty-three percent (2/6, 33%) of femoral neck fractures displaced and required surgery. The remainder of the cohort (13/15, 87%) healed without complication, including all of the intertrochanteric fractures (9/9, 100%). Although this difference did not reach statistical significance, the results may better inform treatment discussions for geriatric patients with occult hip fractures diagnosed by MRI. LEVEL OF EVIDENCE: Level III.

The Effect of Dexamethasone on Postoperative Blood Glucose in Patients With Type 2 Diabetes Mellitus Undergoing Total Joint Arthroplasty.

BACKGROUND: Perioperative glucocorticoids are routinely administered to patients undergoing total joint arthroplasty (TJA) to decrease postoperative pain and nausea. However, there is concern regarding the effects of glucocorticoids on perioperative glucose control in diabetes. The goal of this study is to determine if administration of preoperative dexamethasone to diabetic patients is significantly associated with hyperglycemia and increased insulin requirements in the immediate postoperative period after TJA and to identify risk factors for postoperative hyperglycemia immediately after TJA. METHODS: A retrospective review of type 2 diabetic patients undergoing TJA from 2010 to 2015 (n = 285) was undertaken to evaluate the effect of dexamethasone on postoperative glucose control. Preoperative baseline characteristics were compared between patients who did and did not receive 8 mg of intravenous dexamethasone preoperatively. Postoperative glucose and insulin requirements were evaluated with respect to dexamethasone dosing. Statistical analysis was performed using logistic regression models. RESULTS: Dexamethasone administration did not correlate with the maximum postoperative blood glucose (P = .78). There was a significantly higher initial postoperative blood glucose after intravenous dexamethasone administration (P < .01). Dexamethasone administration was associated with increased aspart insulin requirements on postoperative day 0 (P = .04). However, preoperative hemoglobin A1c was most strongly associated with postoperative glucose control. CONCLUSION: Preoperative dexamethasone administration to diabetic patients was associated with an initial increase in blood glucose and increased insulin requirement on postoperative day 0. Yet the observed effect on glucose control in diabetic patients may not outweigh the known clinical benefits of perioperative glucocorticoids.

Comparison of Tip- Versus Hub-Oscillating Saw Blade Control in a Total Knee Arthroplasty Model.

BACKGROUND: Oscillating saws are commonly used for bone preparation in total knee arthroplasty but can cause injury to the posterior neurovascular bundle during tibial resection. Tip-oscillating saw blades are a recent innovation that could improve saw control due to decreased excursion; however, the tactile feedback to the surgeon is different. METHODS: To compare traditional hub and new tip-oscillating saw blades, 16 participants of varying levels of experience were video-recorded during composite tibial bone model resections to measure posterior saw blade plunge. Subjective perceptions of saw control and preference were also surveyed. RESULTS: Saw blade design and level of surgical experience did not produce a significant difference in posterior saw blade plunge (P > .05). Independent of saw blade design, subjects with no previous saw experience had significantly decreased posterior tibial plunge over subsequent resections. Tip-oscillating saw blades were perceived to be easier to use and control by less experienced participants (P = .0163). CONCLUSION: Tip-oscillating saw blades do not alter the risk of posterior tibial saw plunge compared with traditional saw blades.

Assessment of Early Gait Recovery After Anterior Approach Compared to Posterior Approach Total Hip Arthroplasty: A Smartphone Accelerometer-Based Study.

BACKGROUND: The influence of total hip arthroplasty surgical approach on postoperative recovery is not well understood and often debated. This study compares anterior and posterior approach (PA) gait and patient-reported Hip Osteoarthritis Outcome scores (HOOS) in the early phases of recovery. METHODS: A prospective study evaluated 20 control subjects, 35 direct anterior approach (DAA), and 34 PA total hip arthroplasty patients. Subjects were assessed preoperatively and at 1 and 4 months postoperatively with HOOS and smartphone gait assessments of gait speed, step length, cadence, step symmetry, and horizontal and vertical center of mass displacements. RESULTS: The DAA and PA groups were not different in baseline HOOS or gait characteristics except for less horizontal center of mass displacement in the DAA group. At 1 month postoperatively, the DAA group had significantly faster gait speed at self-selected (P = .02) and fastest possible gait (P = .01) and longer step length at self-selected (P = .047) and fastest gait (P = .003) compared to the PA. At 4 months, there were no differences in DAA and PA gait measures. At 1 month postoperatively there were no significant differences in HOOS, but after 4 months HOOS were significantly higher in the DAA group. CONCLUSION: There were minimal differences between the two approaches in the recovery of gait mechanics with some gait parameters particularly gait speed and step length recovery favoring the DAA at 1 month postsurgery in this nonrandomized study.

The Current Treatment of Hip Fractures: Can a Consensus Be Reached?

There is a significant global burden of disease associated with the management of hip fractures. Despite numerous studies that are focused on the treatment of patients with proximal femur fractures, the management of these injuries remains controversial. Clinicians should become familiar with the current evidence regarding the management of these common injuries and understand the key issues and controversies because they will have important implications given the large-scale effect of hip fractures internationally.

The Intermalleolar Method for Intraoperative Rotational Assessment of the Tibia-A Prospective Clinical Validation Study.

OBJECTIVES: To determine the accuracy of the intermalleolar method, an intraoperative fluoroscopic method for assessing tibial rotation in patients undergoing intramedullary nail fixation for tibial shaft fractures, by comparing it with the gold standard computed tomography (CT). DESIGN: Prospective cohort study. SETTING: Academic Level 1 trauma center. PATIENT SELECTION CRITERIA: Consecutive patients, aged 18 years and older, with unilateral tibial shaft fractures who underwent intramedullary fixation from September 2021 to January 2023. OUTCOME MEASURES AND COMPARISONS: Intraoperatively, tibial rotation measurements were obtained using the intermalleolar method on both the uninjured and injured limbs. Postoperatively, patients underwent bilateral low-dose lower extremity rotational CT scans. CT measurements were made by 4 blinded observers. Mean absolute rotational differences and standard errors were calculated to compare the injured and uninjured limbs. Subgroup analysis was performed assessing accuracy relating to injured versus uninjured limbs, body mass index, OTA/AO fracture pattern, tibial and fibular fracture location, and distal articular fracture extension requiring fixation. RESULTS: Of the 20 tibia fractures, the mean patient age was 43.4 years. The intermalleolar method had a mean absolute rotational difference of 5.1 degrees (standard error 0.6, range 0-13.7) compared with CT. Sixty percent (24/40) of the measurements were within 5 degrees, 90% (36/40) of the measurements were within 10 degrees, and 100% (40/40) were within 15 degrees of the CT. No patients were revised for malrotation postoperatively. CONCLUSIONS: The intermalleolar method is accurate and consistently provides intraoperative tibial rotation measurements within 10 degrees of the mean CT measurement for adult patients undergoing intramedullary nail fixation for unilateral tibial shaft fractures. This method may be employed in the operating room to accurately quantify tibial rotation and assist with intraoperative rotational corrections. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Establishing a surgical partnership between Addis Ababa, Ethiopia, and Toronto, Canada.

BACKGROUND: Academic partnerships between high- and low/middle-income countries can improve the quality of surgical education and health care delivery in each setting. We report the perceived needs related to collaborative surgical education in a resource-limited setting. METHODS: We used qualitative methods to elicit the opinions of surgical faculty members and surgical residents and quantitative methods to outline surgical procedure type and volume. RESULTS: Ethiopian faculty members identified the management of trauma and emergency surgical care as a priority. They identified supervision in the operating room (OR), topic-specific lectures and supervising resident assessments in the clinic as appropriate roles for partners. Residents were in agreement with faculty members, highlighting a desire for supervision in the OR and topic-specific lectures. CONCLUSION: We present specific experiences and needs of a surgical teaching unit in a low-income country, paving the way to form a meaningful and responsive relationship between 2 surgical departments in 2 universities.

CONTEXTE: Les partenariats universitaires entre pays riches et pays à revenus faibles ou moyens peuvent améliorer l'enseignement de la chirurgie et la prestation des soins de santé dans chaque contexte. Nous faisons état des besoins perçus en matière de collaboration pour la formation en chirurgie dans un milieu aux ressources limitées. MÉTHODES: Nous avons utilisé des méthodes qualitatives pour sonder l'opinion des professeurs et des résidents en chirurgie, ainsi que des méthodes quantitatives pour faire le point sur les types d'opérations et leur volume. RÉSULTANTS: Les professeurs éthiopiens ont établi comme priorités la traumatologie et les soins chirurgicaux d'urgence. Ils ont évoqué la supervision au bloc opératoire, les conférences sur des thèmes précis et la supervision de l'évaluation clinique des résidents comme rôles appropriés pour les partenaires. Les résidents ont été du même avis que les professeurs et ont confirmé leur souhait d'être supervisés au bloc opératoire et d'entendre des conférences sur des thèmes précis. CONCLUSIONS: Nous présentons les expériences et les besoins particuliers d'une unité d'enseignement de la chirurgie dans un pays à faible revenu, et nous pavons ainsi la voie pour l'établissement d'un lien de collaboration important et pertinent entre les départements de chirurgie de 2 universités.

The crippling effects of a cyberattack at an academic level 1 trauma center: An orthopedic perspective.

INTRODUCTION: Malicious cyberattacks are increasing in frequency and severity with healthcare institutions spending an average of over 10 million dollars to resolve the consequences of healthcare data breaches. This cost does not include the effect of a downtime event should a healthcare system electronic medical record (EMR) lose functionality. An Academic Level 1 trauma center suffered a cyberattack resulting in a total EMR downtime of 25 days. Orthopedic operative time was used as a surrogate for OR functionality during the event and a framework with specific examples is presented to promote rapid adaptation during downtime events. METHODS: Operative time losses were identified by calculating a running average of weekday total in room operative time during a total downtime event secondary to a cyberattack. This data was compared to week-of-the-year matched data from the year prior and the year after the attack. A framework for creating adaptations to a total downtime event was created by repeatedly interviewing different provider groups and identifying how they adjusted care to the challenges faced. RESULTS: Total weekday in room operative time during the attack decreased by 53.4% ± 12.2% and 53.2% ± 14.9% when comparing the matched period one year prior and one year after, respectively. Immediate challenges to patient care were identified by small groups of highly motivated individuals, with self-assigned agile teams formed. These teams sequenced system processes, identified failure points, and created real-time solutions. A frequently updated EMR backup mirror and hospital disaster insurance were crucial for mitigating the impact of the cyberattack. CONCLUSIONS: Cyberattacks are expensive and their downstream effects, including downtime events, can be crippling. Agile team formation, process sequencing, and understanding EMR backup times are tactics used to combat the challenges of a prolonged total downtime event. LEVEL OF EVIDENCE: Level III retrospective cohort.

Selecting a Press-fit Stem for Total Hip Arthroplasty: The Rationale and Evolution of the Modern Femoral Prosthesis.

Noncemented press-fit femoral stems predominate in total hip arthroplasty for all age groups with generally excellent long-term survivorship. The 2021 American Joint Replacement Registry reports that 96% of all elective primary total hip arthroplasties used noncemented femoral implant fixation. 1 Today, there are many styles of press-fit stems, each with supposed benefits, based on a range of design philosophies. Design aspects to consider when selecting a stem are numerous, including stem geometry, stem length, collared or collarless, material properties, and surface structure. Although most stem designs demonstrate excellent results, the differences in stem designs are intimately linked to additional factors such as ease of use/implantation, percentage of surface osseointegration, overall bone removal versus bone stock preservation, subsequent femoral stress shielding, and consideration of complexity of later revision. A surgeon with a broad understanding and appreciation of femoral stem designs should be prepared to select between the multitude of options to best serve individual patients.

Intraoperative Comparative Femoral Rotation Imaging: Do not Overlook Parallax.

OBJECTIVE: To investigate the degree of error due to parallax during intraoperative rotational imaging involving the distal femur. METHODS: Twelve, fresh-frozen, lower-extremity cadaveric specimens were studied. The limbs were positioned supine and rotated until the posterior femoral condyles were superimposed using a C-arm. The C-arm was then repositioned to place the femoral condyles at the anterior and posterior margins of the image intensifier. The rotation necessary to resuperimpose the femoral condyles due to parallax was recorded. A second C-arm was then used from the contralateral side to simulate the rotational imaging technique to determine the magnitude and directionality of combined parallax. RESULTS: All 12 specimens demonstrated parallax, resulting in rotational discrepancies. Compared with central field of view alignment, the mean rotational discrepancy was 5.6 and 5.5 degrees for anterior and posterior positions, respectively. Contralateral imaging resulted in an additive effect with rotational differences of 9.0 and 12.6 degrees for bilateral anterior and posterior positions, respectively. CONCLUSIONS: Parallax causes rotational discrepancies with fluoroscopic imaging of the distal femur when the posterior femoral condyles are off-center in the imaging field of view. If femoral condyles are not centered when obtaining intraoperative rotational imaging of the uninjured and injured femurs, parallax can result in potentially clinically significant rotational deformity even if the femurs seem perfectly matched at the conclusion of surgery. We recommend perfectly centering of the posterior femoral condyles in the imaging field of view when obtaining lateral images of the distal femur to prevent this potentially overlooked contribution to malrotation.

A Novel Fluoroscopic Method for Assessing Rotational Malalignment of the Tibia.

OBJECTIVE: To evaluate the accuracy and reliability of a novel fluoroscopic technique for assessing tibial rotation and compare it with a previously described fluoroscopic method. METHODS: A multiplanar circular ring external fixator was secured to the tibial diaphysis of 5 cadaveric lower extremity specimens. Using deformity correction software, the frame and tibia were programed to randomly rotate 5, 10, 15, 20, 25, and 30 degrees of internal and external rotation. After each rotation, 2 blinded, independent observers measured the degree of tibial rotation using 2 different fluoroscopic methods: the previously described "mortise" method and the novel "intermalleolar" method. A total of 65 measurements were made by each observer. Accuracy and interobserver reliability were calculated. RESULTS: Both intermalleolar and mortise methods had a mean absolute rotational difference from the true torsion of 3 degrees (standard error 1; range, 0-10 degrees intermalleolar vs. 0-18 degrees mortise). We found that 98.5% (128/130) of measurements using the intermalleolar method were less than 10 degrees from the true rotation compared with 93.8% (122/130) using the mortise method. Both the intermalleolar and the mortise methods had excellent interobserver reliability (intraclass correlation coefficient 0.99 and 0.96, respectively). CONCLUSION: Measuring tibial rotation fluoroscopically using the intermalleolar method is both accurate and reliable. Compared with the previously described mortise method, it has similar accuracy and provides a value that approximates the true tibial rotation. Also, it can be used reliably and effectively intraoperatively to identify tibial malrotation and assist in intraoperative rotational corrections.

Important Factors for Retrograde Nailing Through Total Knee Arthroplasty: A Cadaveric Study.

OBJECTIVES: Evaluate how total knee arthroplasty (TKA) implant design, femoral component size, and preoperative knee range of motion affect retrograde femoral nailing. METHODS: Cadaveric specimens were prepared for TKA with a single radius (SR) or medial pivot (MP) design and tested with cruciate retaining (CR), cruciate substituting (CS), and posterior stabilizing (PS) 9-mm liners. Knee extension identified the minimum flexion required to pass an opening reamer without impinging on TKA components. The angle between the reamer path and the femoral shaft was calculated from lateral fluoroscopic images. RESULTS: In SR TKA, the average flexion required was 70, 71, and 82 degrees for CR, CS, and PS, respectively. The required flexion in PS was significantly greater (P = 0.03). In MP TKA, the average flexion required was 74, 84, and 123 degrees for CR, CS, and PS, respectively. The required flexion was significantly greater in CS and PS designs (P < 0.0001). Femoral component size did not affect the minimum flexion required. The entry reamer resulted in 9.2 (SR) and 12.5 (MP) degrees of apex anterior deviation. CONCLUSIONS: When performing retrograde nailing through either of these TKA designs with a 12-mm opening reamer, at least 70 degrees of knee flexion is required to avoid damage to the polyethylene liner or femoral component. PS implants require significantly more flexion with both TKA designs. Femoral component size did not affect the flexion requirement. Approximately a 10-degree deviation exists between the reamer path and femoral shaft.

Effects of total knee arthroplasty on skeletal muscle structure and function at the cellular, organellar, and molecular levels.

Total knee arthroplasty (TKA) is an important treatment option for knee osteoarthritis (OA) that improves self-reported pain and physical function, but objectively measured physical function typically remains reduced for years after surgery due, in part, to precipitous reductions in lower extremity neuromuscular function early after surgery. The present study examined intrinsic skeletal muscle adaptations during the first 5 weeks post-TKA to identify skeletal muscle attributes that may contribute to functional disability. Patients with advanced stage knee OA were evaluated prior to TKA and 5 weeks after surgery. Biopsies of the vastus lateralis were performed to assess muscle fiber size, contractility, and mitochondrial content, along with assessments of whole muscle size and function. TKA was accompanied by marked reductions in whole muscle size and strength. At the fiber (i.e., cellular) level, TKA caused profound muscle atrophy that was approximately twofold higher than that observed at the whole muscle level. TKA markedly reduced muscle fiber force production, contractile velocity, and power production, with force deficits persisting in myosin heavy chain (MHC) II fibers after expression relative to fiber size. Molecular level assessments suggest reduced strongly bound myosin-actin cross bridges and myofilament lattice stiffness as a mechanism underlying reduced force per unit fiber size. Finally, marked reductions in mitochondrial content were apparent and more prominent in the subsarcolemmal compartment. Our study represents the most comprehensive evaluation of skeletal muscle cellular adaptations to TKA and uncovers novel effects of TKA on muscle fiber size and intrinsic contractility early after surgery that may contribute to functional disability.NEW & NOTEWORTHY We report the first evaluation of the effects of total knee arthroplasty (TKA) on skeletal muscle at the cellular and subcellular levels. We found marked effects of TKA to cause skeletal muscle fiber atrophy and contractile dysfunction in older adults, as well as molecular mechanisms underlying impaired contractility. Our results reveal profound effects of TKA on muscle fiber size and intrinsic contractility early after surgery that may contribute to functional disability.

Reliability of a simple fluoroscopic image to assess leg length discrepancy during direct anterior approach total hip arthroplasty.

BACKGROUND: Direct anterior approach (DAA) total hip arthroplasty (THA) in a supine position provides a unique opportunity to assess leg length discrepancy (LLD) intra-operatively with fluoroscopy. Reported fluoroscopic techniques are useful but are generally complicated or costly. Despite the use of multiple techniques for leg length assessment, LLD continues to be a major post-operative source of patient dissatisfaction further emphasizing the importance of near-anatomic restoration. The utility of an alternative direct measurement of LLD on an intra-operative fluoroscopic pelvic image during DAA THA has not been reported. AIM: To determine the reliability of a novel simple intra-operative measurement of LLD using a parallel line technique on a single fluoroscopic digital image of the pelvis. METHODS: One hundred and seventy-one patients who underwent DAA THA were included for analysis. Intra-operative fluoroscopic and post-operative anterior-posterior radiographs were imported to TraumaCad and calibrated for LLD measurement. LLD was measured on each image using the right-left hip differences in lesser trochanter to pelvic reference line distances. Pelvic reference points included the teardrops and ischia. Fluoroscopic LLD was compared to the gold-standard measurement of LLD measured on a post-operative radiograph. RESULTS: Mean absolute difference in teardrop referenced LLD between fluoroscopic and post-operative radiographs was 2.17 mm and based on the ischia mean absolute difference was 2.63 mm. Linear regression of fluoroscopic and post-operative radiograph LLD based on teardrop and ischia LLD found r 2 values of 0.57 and 0.84, respectively. Mean absolute difference between fluoroscopic and post-operative x-ray LLD was within 5 mm in 95% of cases regardless of pelvic reference. CONCLUSION: This study demonstrates that a single fluoroscopic view obtained during DAA THA for leg length assessment is clinically useful.