Removal of Well-Fixed Tibial Cone in Revision Total Knee Arthroplasty-A Uniquely Challenging Yet Necessary Scenario.

The number of revision total knee arthroplasties (TKA) performed in the United States continues to increase. While advancements in implant design and surgical technique have led to improved outcomes compared with historical data, these cases remain technically demanding with high rates of aseptic failure and worse patient reported outcome scores compared with primary total knee arthroplasty. One particular problem commonly encountered in revision knee arthroplasty is bone loss, particularly in the epiphyseal region, which negatively impacts the structural integrity of the implants. Various modular metaphyseal sleeves and cones in conjunction with stemmed implants have been designed to enhance metaphyseal fixation, corroborated by multiple studies demonstrating excellent midterm results involving cones, and sleeves. Commercially available revision systems that incorporate metaphyseal cones are currently widely utilized in revision TKA. For tibial defects, both symmetric and asymmetric cone options are available. Excellent midterm results have been reported with use of this device in the setting of severe proximal tibial bone loss in revision TKA surgery. With the enhanced fixation provided by various sleeve and cone augments, implant removal in the setting of recurrent infection or implant failure can be extremely challenging. Consequently, in this work, we sought to describe an algorithmic approach for removing a tibial cone in conjunction with the overlying tibial baseplate. A review of the literature has also been conducted for complex surgical techniques regarding removal of well-fixed implants in revision total knee arthroplasty.

The effect of body mass index on 30-day complications after total hip arthroplasty.

BACKGROUND: Evaluating body mass index (BMI) as a continuous variable eliminates the potential pitfalls of only considering BMI as a binary or categorical variable, as most studies do when correlating BMI and total hip arthroplasty (THA) outcomes. Therefore, the objective of this study was to correlate the effect of continuous BMI on 30-day complications post-THA. Specifically, we correlated BMI to: (1) 30-day readmissions and reoperations; (2) medical complications; and (3) surgical complications in: (a) normal-weight; (b) over-weight; (c) obese; and (d) morbidly obese patients. METHODS: Using the NSQIP database, 93,598 primary THAs were identified. 30-day rates of readmissions, reoperations, and medical/surgical complications as well as patient BMI data were extrapolated. A comparative analysis using univariate, multivariate, and spline regression models adjusting for demographics and comorbidities were created to study the continuous effect of BMI on different outcomes. RESULTS: Readmission (p < 0.001), reoperation (p = 0.007), superficial infection (p = 0.003), prosthetic joint infection (p < 0.001), and sepsis (p = 0.026) had a J-shaped relationship with BMI, with the lowest rates seen in patients with BMI around 28 kg/m2. The risks of mortality (p = 0.007) and transfusion (p < 0.001) had a reverse J-shaped relationship, with the risk steadily decreasing for BMIs in the normal weight and overweight range, and then flattening afterwards. CONCLUSION: This data proposes a multifactorial effect of BMI on post-THA complications. Considering BMI as a continuous variable allows for a better assessment when considering the interplay between modifiable risk factors, such as smoking or alcohol use, as well as multiple comorbidities.

Catastrophic tibial baseplate failure of a modern cementless total knee arthroplasty implant.

Tibial baseplate fracture following primary total knee arthroplasty is a rare complication, particularly with modern implants and surgical techniques. This case details the first known report of mid-range follow-up catastrophic failure of a cementless modular, trabecular metal tibial baseplate. This failure highlights the importance of continued follow-up for novel implants, to include cementless knee arthroplasty designs, particularly if new symptoms arise or periarticular bone loss is identified on radiograph.

Bilateral Patellar Stress Fractures in a Skeletally Immature Athlete: A Case Report.

CASE: This report describes the divergent course and management of bilateral patellar stress fractures in a 17-year-old skeletally immature male athlete. Beginning as bilateral incomplete tension-sided patellar fractures, the right patella healed uneventfully, whereas the left progressed to a complete, mildly displaced transverse fracture that eventually healed with nonoperative treatment measures to include temporary bracing, physical therapy, and vitamin D supplementation. CONCLUSIONS: Patellar stress fractures are exceptionally rare, particularly bilateral injuries in the pediatric population. Diligent workup is necessary for appropriate diagnosis, whereas knowledge of the salient features of these injuries is useful in treatment.

Surgical Tips for Performing Open Fasciotomies for Chronic Exertional Compartment Syndrome of the Leg.

Chronic exertional compartment syndrome (CECS) of the leg is a debilitating condition that has previously been characterized in athletes and military personnel. The results of surgical management in these patient populations have previously been published with inconsistencies in surgical methods and patient outcomes noted. While endoscopic and minimally invasive techniques have been described, a detailed description of a "standard" open, 2-incision lateral and single-incision medial technique for the treatment of CECS has not been previously published. The purpose of this technique article is to highlight several tips and considerations related to this procedure in the hopes of standardizing treatment and potentially improving patient outcomes. Level of Evidence: Level V, expert opinion.

Femoral Neck Stress Injuries: Analysis of 156 Cases in a U.S. Military Population and Proposal of a New MRI Classification System.

OBJECTIVE: The objective of this study is to formulate a new MRI classification system for fatigue-type femoral neck stress injuries (FNSIs) that is based on patient management and return-to-duty (RTD) time. MATERIALS AND METHODS: A retrospective review of 156 consecutive FNSIs in 127 U.S. Army soldiers over a 24-month period was performed. The width of marrow edema for low-grade FNSIs and the measurement of macroscopic fracture as a percentage of femoral neck width for high-grade FNSIs were recorded. RTD time was available for 90 soldiers. Nonparametric testing, univariate linear regression, and survival analysis on RTD time were used in conjunction with patient management criteria to develop a new FNSI MRI classification system. RESULTS: The FNSI incidence was 0.09%, and all FNSIs were compressive-sided injuries. RTD time was significantly longer for high-grade FNSIs versus low-grade FNSIs (p < 0.001). Our FNSI MRI classification system showed a significant difference in RTD time between grades 1 and 2 (p = 0.001-0.029), 1 and 3 (p < 0.001), and 1 and 4 (p = 0.001-0.01). There was no significant RTD time difference between the remaining grades. The rates of completing basic training (BT) and requiring medical discharge were significantly associated with the FNSI MRI grades (p = 0.038 and p = 0.001, respectively). CONCLUSION: The proposed FNSI MRI classification system provides a robust framework for patient management optimization by permitting differentiation between operative and nonoperative candidates, by allowing accurate prediction of RTD time, and by estimating the risk of not completing BT and requiring medical discharge from the military.

Biomechanical Evaluation of Unicortical Stress Risers of the Proximal Humerus Associated With Pectoralis Major Repair.

Proximal humerus fracture after pectoralis major tendon repair has been recently reported. Although this complication is rare, it may be possible to decrease such risk using newer techniques for myotenodesis. This study was designed to evaluate various unicortical stress risers created at the proximal humeral metadiaphysis during myotenodesis for repair of pectoralis major ruptures. A simulated pectoralis major myotenodesis was performed using fourth-generation Sawbones (N=30). Using previously described anatomic landmarks for the tendinous insertion, 3 repair techniques were compared: bone trough, tenodesis screws, and suture anchors (N=10 each). Combined compression and torsional load was sequentially increased until failure. Linear and rotational displacement data were collected. The average number of cycles before reaching terminal failure was 383 for the bone trough group, 658 for the tenodesis group, and 832 for the suture anchor group. Both the tenodesis and the suture anchor groups were significantly more resistant to fracture than the bone trough group (P<.001). The suture anchor group was significantly more resistant to fracture than the tenodesis group (P<.001). All test constructs failed in rotational stability, producing spiral fractures, which incorporated the unicortical defects in all cases. When tested under physiologic parameters of axial compression and torsion, failure occurred from rotational force, producing spiral fractures, which incorporated the unicortical stress risers in all cases. The intramedullary suture anchor configuration proved to be the most stable construct under combined axial and torsional loading. Using a bone trough technique for proximal humerus myotenodesis may increase postoperative fracture risk. [Orthopedics. 2017; 40(5):e801-e805.].

Biomechanical analysis of intramedullary vs. superior plate fixation of transverse midshaft clavicle fractures.

BACKGROUND: Middle-third clavicle fractures represent 2% to 4% of all skeletal trauma in the United States. Treatment options include intramedullary (IM) as well as plate and screw (PS) constructs. The purpose of this study was to analyze the biomechanical stability of a specific IM system compared with nonlocking PS fixation under low-threshold physiologic load. METHODS: Twenty fourth-generation Sawbones (Pacific Research Laboratories, Vashon, WA, USA) with a simulated middle-third fracture pattern were repaired with either an IM device (n = 10) or superiorly positioned nonlocking PS construct (n = 10). Loads were modeled to simulate physiologic load. Combined axial compression and torsion forces were sequentially increased until failure. Data were analyzed on the basis of loss of rotational stability using 3 criteria: early (10°), clinical (30°), and terminal (120°). RESULTS: No significant difference was noted between constructs in early loss of rotational stability (P > .05). The PS group was significantly more rotationally stable than the IM group on the basis of clinical and terminal criteria (P < .05 for both). All test constructs failed in rotational stability. CONCLUSIONS: When tested under physiologic load, fixation failure occurred from loss of rotational stability. No statistical difference was seen between groups under early physiologic loads. However, during load to failure, the PS group was statistically more rotationally stable than the IM group. Given the clavicle's function as a bony strut for the upper extremity and the biomechanical results demonstrated, rotational stability should be carefully considered during surgical planning and postoperative advancement of activity in patients undergoing operative fixation of middle-third clavicle fractures. LEVEL OF EVIDENCE: Basic Science Study; Biomechanics.

Evolving Role of Ultrasound in Therapeutic Injections of the Upper Extremity.

Ultrasound machines are creating more refined pictures and becoming more user-friendly and readily accessible. As a result, ultrasound is being increasingly used for therapeutic purposes. One example involves the use of ultrasound guidance in musculoskeletal interventional procedures, such as joint injections, tendon sheath injections, and peripheral nerve blocks. Technical considerations and therapeutic results have been described for multiple locations about the upper extremities, with varying levels of success. The implementation of ultrasound-guided injections in the orthopedist's clinic has therapeutic, financial, and provider role implications. Given these potential benefits, orthopedic providers, both in practice and residency, would benefit from increased exposure and education in ultrasound use. Ultrasound provides the benefit of real-time, dynamic imaging without the radiation exposure of fluoroscopy, and ultrasound-guided injections can be performed in the office, as opposed to the operating room, which is frequently required when using fluoroscopy. A basic knowledge of the principles and terms used in ultrasound is required. With these simple principles, a practitioner can review techniques for specific areas of the musculoskeletal system and begin using ultrasound to guide injections. Many locations for diagnostic and/or therapeutic injections in the upper extremities have improved accuracy and benefit with the use of ultrasound vs blind techniques, although a few have not been shown to have a significant difference in the literature. The educational and professional implications can be significant, but these potential benefits need to be carefully weighed against costs by each orthopedic practice.

Injection-induced gluteus muscle contractures: diagnosis with the "reverse Ober test" and surgical management.

BACKGROUND: Adoption rates are increasing in the United States and other developed countries. A large proportion of adopted children have been found to have unsuspected medical diagnoses, including orthopedic problems. One condition, termed injection-induced gluteus maximus contracture, has been previously described in several case series and can be difficult to diagnose if unfamiliar with this condition. By reviewing the etiology and pathoanatomy of this problem, as well as the typical examination findings, including the near-pathognomonic-positive "reverse Ober test," treating providers will be better prepared to recognize and properly treat this condition. METHODS: This is a retrospective review of 4 patients treated at our institution for injection-induced gluteus maximus contracture. Patient history, physical examination findings, and treatment outcomes were recorded. All had undergone surgical treatment through a longitudinal incision along the posterior margin of the iliotibial band, with division of thickened, contracted gluteus tissue down to the ischial tuberosity. RESULTS: All 4 of the patients were adopted from orphanages in developing countries. Chief complaints of the patients varied, but physical examination findings were very consistent. Three of the 4 patients had undergone rotational osteotomies for presumed femoral retroversion before their diagnosis and treatment for injection-induced gluteus maximus contracture. All patients had concave, atrophic buttock contours and numerous punctate buttock scars. All walked with an out-toed gait and had marked apparent femoral retroversion. Each patient was found to have full hip adduction when the hip was extended but a hip abduction contracture when the hip was flexed. This finding of increasing abduction as an extended/adducted hip is flexed to 90 degrees is described as a positive "reverse Ober test." After surgical treatment, all hips could adduct to neutral from full extension to full flexion. CONCLUSIONS: Although common in some countries, such as Russia and China, injection-induced gluteus muscle contractures are seldom seen in the United States and other developed countries. Diagnosis of this condition can be difficult leading to inappropriate treatment. Knowledge of the clinical presentation typical of a gluteus contracture and of the pathognomonic finding of a "reverse Ober test" can facilitate an effective surgical procedure to correct the associated functional impairment. LEVEL OF EVIDENCE: Level IV: retrospective case series.