Interobserver Reliability and Change in the Sagittal Tibial Tubercle-Trochlear Groove Distance with Increasing Knee Flexion Angles.

The tibial tubercle-trochlear groove (TT-TG) distance is currently utilized to evaluate knee alignment in patients with patellar instability. Sagittal plane pathology measured by the sagittal tibial tubercle-trochlear groove (sTT-TG) distance has been described in instability but may also be important to consider in patients with cartilage injury. This study aims to (1) describe interobserver reliability of the sTT-TG distance and (2) characterize the change in the sTT-TG distance with respect to changing knee flexion angles. In this cadaveric study, six nonpaired cadaveric knees underwent magnetic resonance imaging (MRI) studies at each of the following degrees of knee flexion: -5, 0, 5, 10, 15, and 20. The sTT-TG distance was measured on the axial T2 sequence. Four reviewers measured this distance for each cadaver at each flexion angle. Intraclass correlation coefficients were calculated to determine interobserver reliability and reproducibility of the sTT-TG measurement. Analysis of variance (ANOVA) tests and Friedman's tests with a Bonferroni's correction were performed for each cadaver to compare sTT-TG distances at each flexion angle. Significance was defined as p < 0.05. There was excellent interobserver reliability of the sTT-TG distance with all intraclass correlation coefficients >0.9. The tibial tubercle progressively becomes more posterior in relation to the trochlear groove (more negative sTT-TG distance) with increasing knee flexion. The sTT-TG distance is a measurement that is reliable between attending surgeons and across training levels. The sTT-TG distance is affected by small changes in knee flexion angle. Awareness of knee flexion angle on MRI is important when this measurement is utilized by surgeons.

Microdrilling Demonstrates Superior Patient-Reported Outcomes and Lower Revision Rates Than Traditional Microfracture: A Matched Cohort Analysis.

PURPOSE: The purpose of this study was to compare patient-reported outcomes and revision rates between the standard microfracture awl versus the microdrilling technique. METHODS: Microfracture patients were queried from a single-institution database between 2001 and 2016. Patient-reported outcome measure data were collected at preoperative and 6- and 12-month time points, inclusive of the International Knee Documentation Committee (IKDC) score, Short Form 12 (SF12) Physical Component Score (PCS) and Mental Component Score, and all Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales. A matching algorithm based on previous procedures, lesion size, and demographic factors created 2 technique-based cohorts. Outcomes including revision rates and both statistically and clinically significant differences (i.e., the minimally clinically important difference [MCID]) between awl and microdrill cohorts were compared using univariate statistics. RESULTS: A total of 68 patients (aged 32.0 ± 13.1 years, 48.5% female, body mass index 26.7 ± 5.3 kg/m2), with 34 patients in each group, were included after the match. At 6 months, the microdrilling group demonstrated significantly greater levels of improvement than the awl group on the IKDC, SF12 PCS, and KOOS Pain, Symptom, Sport, and Quality of Life (P < .04), although differences at 1 year were only maintained on the SF12 PCS instrument (P < .001). With respect to MCID achievement, the microdrilling group demonstrated greater achievement rates at 6 months on the IKDC, KOOS Pain, and KOOS Sport (P < .04). The awl group demonstrated a higher rate of revision surgery (P = .02) within 3 years of follow-up and a greater likelihood to require multiple subsequent procedures (41.1% vs 17.6%, P = .03). CONCLUSIONS: Microdrilling demonstrated superior outcomes relative to traditional microfracture awl techniques with respect to patient-reported outcomes at 6 months and revision rates within 3 years of follow-up. In addition, clinically meaningful differences were evident at 6 months in the microdrilling group. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Effects of implant rotational malposition on contact surface area after implantation of the augmented glenoid baseplate in the setting of glenoid bone loss.

AIM OF THE STUDY: Augmented glenoid baseplates are utilized in reverse total shoulder arthroplasty in the setting of glenoid bone loss. These implants permit lateralization of the joint line and correction of bony version abnormalities. To allow bone preservation in the setting of abnormal bony version or deficiency, the backside of the augmented glenoid baseplate is not perpendicular to the axis of the central post/screw. Thus, if the baseplate is implanted with any rotational malposition, this could affect the backside contact area available for ingrowth. The purpose of this study was to assess if rotational malpositioning of a full-wedge augmented baseplate alongside the axis of the central screw significantly affects the glenoid implant backside contact area. METHODS: Seven synthetic scapulas (Sawbones, Vashon, WA) were used to implant a 15° full-wedge glenoid baseplate (Wright Medical, Memphis, TN) according to the manufacturer's technique. The contact pressure between the baseplate and the glenoid surface at rotational positions 5°, 10°, and 15° clockwise (CW) and counterclockwise (CCW) from the central axis was measured with Extreme Low Fujifilm Prescale (Tekscan, Boston, MA). The data was analyzed digitally to obtain a percentage of contact surface area. To evaluate gross contact, a computed tomography (CT) scan was performed and manual measurements of contact between the glenoid and the baseplate were conducted using a standardized axial CT slice. RESULTS: The average contact area at zero degrees of malrotation was 37.26 ± 3.27%. Average contact areas for the simulated malposition cases were 13.99 ± 9.39% at 15° CCW, 24.89 ± 5.11% at 10° CW, and 19.32 ± 3.13% at 15° CW. Each of these results was significant (p < 0.003). On computed tomography, at 15° CCW, the contact area decreased by 39%; at 15° CW, the contact area decreased by 38%. DISCUSSION: The use of augmented glenoid baseplates presents a technical challenge. It is difficult to avoid implant malrotation along the axis of the central peg/screw, because the final rotation of the baseplate must be chosen while the implant is several centimeters away from the bone. This study found that 10° and 15° malrotation about the glenoid baseplate's central axis leads to significant decreases in the implant-bone contact area. CONCLUSIONS: When implanting an augmented baseplate for total shoulder arthroplasty, it is important to minimize baseplate malrotation to decrease the risk of baseplate loosening.

Patient-Reported Outcomes Measurement Information System (PROMIS) Instruments Correlate Better With Legacy Measures in Knee Cartilage Patients at Postoperative Than at Preoperative Assessment.

PURPOSE: To define the psychometric properties of the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF), Pain Interference (PI), and Depression computer adaptive tests (CATs) in patients undergoing knee cartilage surgical procedures. METHODS: The PROMIS PF, PI, and Depression CATs were administered preoperatively and at 6 months alongside legacy knee patient-reported outcome measures (PROMs) in patients undergoing knee cartilage surgical procedures. Statistical analysis consisted of the time to completion, psychometric analysis for correlative strengths, absolute and relative floor and ceiling effects, and Cohen effect size. RESULTS: Our study included 250 patients (57.2% male patients), averaging 1.87, 1.53, and 1.91 minutes for completion of the PF, PI, and Depression CATs, respectively. Preoperatively, the PROMIS PF and PI CATs showed wide ranges of correlation coefficients with respect to function (r = 0.14-0.72 and r = 0.29-0.77, respectively) and health-related quality-of-life PROMs (r = 0.64-0.70). At 6 months, the PROMIS PF CAT (r = 0.82-0.93) and PI CAT (r = 0.77-0.93) both exhibited excellent correlations with respect to legacy function and health-related quality-of-life PROMs except for the Marx Activity Rating Scale (r = 0.36-0.44). None of the PROMIS instruments exhibited any significant floor or ceiling effects. CONCLUSIONS: The PROMIS PF, PI, and Depression CATs performed better with respect to legacy PROMs in the postoperative period than the preoperative period. In addition, the PROMIS PF and PI measures performed best with respect to the International Knee Documentation Committee questionnaire, and no floor or ceiling effects were identified for the PROMIS instruments. The PROMIS instruments may be more suited to track outcomes postoperatively than to establish preoperative baselines in cartilage surgery patients. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Meniscal Allograft Transplants.

Meniscus allograft transplantation is an established surgical treatment indicated in symptomatic meniscus-deficient patients with minimal to no arthritis. Treatment decision making should be individualized after a thorough history and physical examination, with diagnostic imaging and arthroscopy to assess the status of the meniscus. The senior author prefers to use a bridge-in-slot technique, where osseous fixation of the allograft is completed through passage of a bone bridge to a tibial slot. Outcomes in meniscus allograft transplantation are favorable, with reported significant improvements in clinical outcome and low failures in short- and midterm follow-up studies.

Clinical Outcomes of Revision Osteochondral Allograft Transplantation.

PURPOSE: To assess the survivorship, clinical outcomes, and radiographic outcomes of patients who have undergone revision osteochondral allograft (OCA) to the knee in a retrospective case series. METHODS: Nine patients who underwent revision OCA by the senior author between January 2003 and December 2015 with a minimum follow up of 2 years were reviewed retrospectively. Patients completed patient-reported outcome surveys containing the visual analog scale, the International Knee Documentation Committee, the Knee injury and Osteoarthritis Outcome Score, Lysholm score, and the Short-Form 12. Radiographic analysis included anteroposterior view graded via the Kellgren and Lawrence scale. Complications and reoperations were analyzed, with failure defined as conversion to arthroplasty. (Institutional review board 15050301.) RESULTS: One of 10 consecutive patients was lost to follow up, for an overall follow-up rate of 90% (5 males, 4 females); mean follow up, 4.53 ± 3.17 years. The median patient age at the time of revision OCA was 33 years (interquartile range [IQR], 8.6), the median defect size was 4.0 cm2 (IQR, 0), and the median time from index OCA to revision OCA was 2.9 years (IQR, 1.9). Five patients (50%) underwent subsequent surgery at a median of 1.92 years (IQR, 7.25), with 1 progressing to arthroplasty at 23 months after revision OCA, for an overall failure rate of 11%. There were no significant differences in any of the patient-reported outcome assessments compared with prerevision OCA (postindex OCA) values at final follow up (P > .05 for all). Similarly, there were no significant differences in Kellgren and Lawrence score before and after surgery (P = .1). CONCLUSIONS: At a mean 4.5 years following revision OCA, there was an 89% graft survivorship rate in a series of 9 patients, with no statistical changes in the radiographic progression of arthritis. LEVEL OF EVIDENCE: Level IV, case series.

Distal Femoral Osteotomy and Lateral Meniscus Allograft Transplant.

Distal femoral varus-producing osteotomy can be performed in the setting of lateral meniscal transplant to correct valgus malalignment of the knee and thus offload the lateral compartment. Advantages of a lateral opening wedge over medial closing wedge osteotomy include a single bone cut, avoidance of vascular structures, and theoretically better control of the amount of correction. It is important to address all knee joint comorbidities, including meniscal deficiency, chondral and osteochondral defects, and ligamentous insufficiency. This article reviews indications, preoperative considerations, technique, postoperative rehabilitative protocol, and results in the literature associated with concurrent varus-producing distal femoral osteotomy and lateral meniscal transplant.

Orthobiologics for Focal Articular Cartilage Defects.

Focal chondral defects of the knee are extremely common and often result in pain, dysfunction, joint deterioration, and, ultimately, the development of osteoarthritis. Due to the limitations of conventional treatments for focal chondral defects of the knee, orthobiologics have recently become an area of interest. Orthobiologics used for cartilage defects include (but are not limited to) bone marrow aspirate concentrate, adipose-derived mesenchymal stem cells, platelet-rich plasma, and micronized allogeneic cartilage. Each of these products can be applied in the clinical setting, as an isolated surgical procedure, or as an augment to cartilage restoration surgery.

The Use of Platelet-Rich Plasma in Symptomatic Knee Osteoarthritis.

With average life expectancy and the rising prevalence of obesity, osteoarthritis (OA) is creating an increasingly large financial and physical burden on the U.S. population today. As the body ages and experiences trauma, articular cartilage surfaces in joints are gradually worn away, leading to OA. Traditionally, treatment options have included lifestyle modifications, pain management, and corticosteroid injections, with joint replacement reserved for those who have exhausted nonsurgical measures. More recently, hyaluronic acid, micronized dehydrated human amniotic/chorionic membrane tissue, and platelet-rich plasma (PRP) injections have started to gain traction. PRP has been shown to have both anti-inflammatory effects through growth factors such as transforming growth factor-ß and insulin-like growth factor 1, and stimulatory effects on mesenchymal stem cells and fibroblasts. Multiple studies have indicated that PRP is superior to hyaluronic acid and corticosteroids in terms of improving patient-reported pain and functionality scores. Unfortunately, there are many variations in PRP preparation, and lack of standardization in factors, such as speed and duration of centrifugation, leads to wide ranges of platelet and leukocyte concentrations. This review examines the current literature addressing the use of PRP in symptomatic knee OA and addresses suggestions for future studies in this area.

Editorial Commentary: Fresh-Frozen Meniscal Allografts-Cold Does Not Always Cause Shrinkage.

Meniscal allograft transplantation is an effective treatment for the symptomatic, young, active patient with meniscal deficiency. Modern graft-preservation techniques may reduce clinical sequelae of meniscal shrinkage after transplantation. We prefer fresh-frozen nonirradiated allografts because of easier processing, lower immunogenicity, and lower cost, and on the basis of a 2-decade clinical experience with fresh-frozen meniscal allograft transplantations, we are pleased with our survivorship results.

Preservation of Knee Articular Cartilage.

Hyaline articular cartilage is critical for the normal functioning of the knee joint. Untreated focal cartilage defects have the potential to rapidly progress to diffuse osteoarthritis. Over the last several decades, a variety of interventions aiming at preserving articular cartilage and preventing osteoarthritis have been investigated. Reparative cartilage procedures, such as microfracture, penetrate the subchondral bone plate in effort to fill focal cartilage defects with marrow elements and stimulate fibrocartilaginous repair. In contrast, restorative cartilage procedures aim to replace the defective articular surface with autologous or allogeneic hyaline cartilage. This review focuses on the preservation of articular cartilage, and discusses the current reparative and restorative surgical techniques available for treating focal cartilage defects.

Microwave-specific acceleration of a Friedel-Crafts reaction: evidence for selective heating in homogeneous solution.

Thermally promoted Friedel-Crafts benzylation of arene solvents has been examined under both conventional convective heating with an oil bath and heating using microwave (MW) energy. Bulk solution temperatures-as measured by internal and external temperature probes and as defined by solvent reflux-were comparable in both sets of experiments. MW-specific rate enhancements were documented under certain conditions and not others. The observed rate enhancements at a given temperature are proposed to arise from selective MW heating of polar solutes, perturbing thermal equilibrium between the solute and bulk solution. Central to MW-specific thermal phenomena is the difference between heat and temperature. Temperature is a measure of the ensemble average kinetic molecular energy of all solution components, but temperature does not provide information about solute-specific energy differences that may arise as a consequence of selective MW heating. Enhanced chemical reactivity of the MW-absorbing solute can be described as a MW-specific "extra-temperature thermal effect", because the measurable solution temperature only captures a portion of the solute kinetic molecular energy. Experimental factors that favor MW-specific rate enhancements are discussed with an eye toward future development of MW-actuated organic reactions, in which the observed thermal reactivity exceeds what is predicted from temperature-based Arrhenius calculations.