The relationship of body mass index on patient reported outcomes after platelet-rich plasma versus microfragmented adipose tissue for knee osteoarthritis: A secondary analysis of a randomized controlled trial.

OBJECTIVE: Body mass index (BMI) is known to contribute to outcomes for patients with knee OA. Furthermore, BMI influences the protein expression of orthobiologic treatments like platelet-rich plasma (PRP) and microfragmented adipose tissue (MFAT). We performed a secondary analysis of the association of BMI with PROs for patients with knee OA who received either PRP or MFAT injections. METHODS: Seventy-one patients with knee OA were randomized to receive a single ultrasound-guided injection of PRP or MFAT. PRP was created from 180cc of anti-coagulated blood and processed using a double-spin, buffy-coat concentration system. MFAT was created using autologous lipoaspirate that was processed according to minimal manipulation guidelines. PROs, and osteoarthritis outcome scores (KOOS) were tracked for 12-months. RESULTS: Forty-nine patients (PRP=23, MFAT=26) completed 12-month follow-up. KOOS- Quality of life and activity of daily living subscores were inversely correlated (both p < 0.05) with BMI in the MFAT but not PRPgroup. KOOS-Pain and Sport subscores showed a trend towards inverse correlation with BMI in the MFAT group (p = 0.07 and p = 0.06, respectively), but not PRP.Conclusion: BMI was negatively associated with PROs in patients who received MFAT injections for knee OA, but not for patients receiving PRP.

Microfragmented Adipose Tissue Is Equivalent to Platelet-Rich Plasma for Knee Osteoarthritis at 12 Months Posttreatment: A Randomized Controlled Trial.

Background: Platelet-rich plasma (PRP) is an effective treatment for knee osteoarthritis (OA). Microfragmented adipose tissue (MFAT) is another orthobiologic that holds promise, but data supporting its use are limited. Previous studies showed that MFAT created using the Lipogems device was equivalent to PRP created via noncommercial laboratory-based processes. Purpose: To perform a comparison of commercially available MFAT and PRP systems for treatment of knee OA. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: A total of 71 patients with symptomatic knee OA (Kellgren-Lawrence grades 1-4) were randomized to receive a single injection of either leukocyte-rich PRP (Angel; Arthrex) or MFAT (Lipogems) under ultrasound guidance. Patient-reported outcomes (Knee injury and Osteoarthritis Outcome Score [KOOS], visual analog scale for pain with activities of daily living [VAS pain], and Tegner activity level) were recorded at baseline and at 1, 3, 6, and 12 months after injection. The primary outcome was the KOOS-Pain subscale score at 12 months after injection. Results: Overall, 49 patients completed their 12-month follow-up (PRP group, n = 23; MFAT group, n = 26). All demographic features were similar between groups, except that more men were randomized to the PRP group and more women to the MFAT group. At 12 months posttreatment, KOOS-Pain scores improved in both groups, with no significant group difference (PRP, 78 ± 17.9 vs MFAT, 77.8 ± 19.3; P = .69). Similarly, other KOOS subscales, VAS pain scores, and Tegner scores improved at 12 months, with no differences between treatment groups. Conclusion: Both PRP and MFAT injections for knee OA resulted in improved patient-reported outcomes at 12 months posttreatment, with no differences found between treatments. Registration: NCT04351087 (ClinicalTrials.gov identifier).

Tobramycin and Vancomycin in an In Vitro Model of Anterior Cruciate Ligament Allograft Decontamination.

BACKGROUND: Approximately 100,000 anterior cruciate ligament (ACL) reconstructions (ACLRs) occur annually in the United States, and postoperative surgical-site infection is a relatively rare but devastating complication, often leading to graft failure or septic arthritis of the knee, necessitating repeat surgery. Wrapping allografts in vancomycin-soaked gauze has been adopted as a common sterilization technique in the operating room to reduce surgical-site infection; however, identifying effective alternatives to vancomycin has not been extensively pursued. HYPOTHESIS: Tobramycin would be as effective as vancomycin in reducing the concentrations of Staphylococcus epidermidis bacteria on tendon allografts. STUDY DESIGN: Controlled laboratory study. METHODS: S. epidermidis strain ATCC 12228 was inoculated onto the human cadaveric gracilis tendon. The tendons were wrapped in sterile gauze saturated with tobramycin or vancomycin at various experimental concentrations. Bacteria remaining on the tendon were dislodged, serially diluted, and plated for colony counting. Statistical analysis was performed utilizing 2-way analysis of variance testing. Results were considered statistically significant when P < .05. RESULTS: Vancomycin (P = .0001) and tobramycin (P < .0001) reduced bacterial concentration. Tobramycin was found to produce a statistically significant reduction in bacterial concentration at concentrations as low as 0.1 mg/mL (P < .0001 and P = .01 at 10 and 20 minutes), while vancomycin produced a statistically significant reduction at a concentration as low as 2.5 mg/mL (P < .0001 at both 10 and 20 minutes). CONCLUSION: This study demonstrates that tobramycin is as effective as vancomycin in bacterial concentration reduction but can achieve this reduction level at lower doses. Further studies clarifying the biomechanical and cytotoxic effects of tobramycin on tendon tissue are indicated to solidify its use as a clinical alternative to vancomycin in ACLR. CLINICAL RELEVANCE: These results will begin establishing tobramycin as an alternative to vancomycin in ACL graft decontamination. Because of relatively frequent shortages of vancomycin, establishing tobramycin as an alternative agent is a useful option for the orthopaedic surgeon.

An All-Suture-Based Technique for Meniscal Repair Is Cost-Effective in Comparison to Partial Meniscectomy for Horizontal Cleavage Tears.

Purpose: To determine the cost-effectiveness of meniscal repair (MR) using an all-suture-based technique when compared to partial meniscectomy (PM) for horizontal cleavage tears (HCTs) from a payor's perspective in the United States. Methods: A state-transition model and cost-utility analysis were developed from a US payor's perspective to project treatment costs and quality-adjusted life-years (QALYs) in a cohort of 35-year-old patients without osteoarthritis at baseline and presenting with either a lateral or medial HCT. Two outpatient costing perspectives were used, namely ambulatory surgical centers (ASCs) and hospitals. The state-transition model had 7 health states with transition probabilities, costs, and utilities obtained from the existing literature. Cost-effectiveness was assessed using a willingness-to-pay threshold of $100,000/QALY, and sensitivity analysis considered the effects of parameter uncertainty on model results. MR failure rates were focused on an all-suture-based technique; however, in a separate scenario, this study considered effectiveness data from various MR techniques and devices. Results: MR dominated PM over a lifetime horizon, increasing QALYs by 0.43 per patient and decreasing the cost by $12,227 per patient within a hospital setting (and by $12,570 within an ASC). MR with an all-suture-based technique continued to be the dominant treatment when age at primary treatment was varied between 30 and 60 years. Sensitivity analysis showed that MR was not cost-effective in year 1, was cost-effective from year 2, and was cost-saving from year 6 onward from both ASC and hospital perspectives. Probabilistic sensitivity analysis found that MR was cost-effective over a lifetime horizon in 99% of 10,000 iterations on base-case analysis. Conclusions: Using a lifetime horizon, this study found that from a payor's perspective, MR is a cost-saving intervention when compared with PM in patients with an HCT. Level of Evidence: Level III, economic analysis.

Editorial Commentary: Low-Grade Infections May Contribute to Anterior Cruciate Ligament Reconstruction Graft Failure.

The etiology of anterior cruciate ligament (ACL) reconstruction failure is often multifactorial, and the role of subclinical bacterial colonization in ACL reconstruction failure has not been fully elucidated. Although the presence of bacterial metabolism in and of itself does not indicate true clinical infection, low-grade infections may contribute to ACL reconstruction graft failure. Bacterial biofilms on soft tissue grafts are shown to change the crimp patterns of collagen and lower graft load to failure. In addition, bacterial DNA has been reported in 80-87% of failed ACL grafts during revision surgery compared to only 20% of primary ACL grafts. Also, higher bacterial DNA concentration is associated with tibial tunnel widening. Further study is needed to establish if any causal relationship between bacterial colonization and ACL graft failure exists. But it does seem that the circumstantial evidence is pointing to such a relationship.

Intercondylar Notch Pathology.

The intercondylar notch of the knee is a relatively small area. However, numerous rare pathologies can arise in this region. A majority of the existing literature has focused on the cruciate ligament injuries, yet there are several other entities that can cause knee pain from within the intercondylar notch. This review focuses on identifying the various diagnostic and treatment options for rare benign and malignant lesions including ganglion cyst formation, mucoid degeneration, benign proliferative conditions, and intra-articular tumors. These entities are most often diagnosed with advanced imaging studies and treated arthroscopically. While rare, these pathologies are important to identify in patients with ongoing vague knee pain.

Increased Body Mass Index is Associated with Worse Mid- To Long-Term Patient Outcomes after Surgical Repair of Multiligamentous Knee Injuries.

We evaluated the relationship between elevated body mass index (BMI) and mid- to long-term outcomes after surgical treatment of multiligamentous knee injury (MLKI). Records identified patients treated surgically for MLKI at a single institution. Inclusion criteria: minimum 2 years since surgery, complete demographics, surgical data, sustained injuries to two or more ligaments in one or both knees, and available for follow-up. Patients were contacted to complete patient-reported outcomes assessments and were classified according to mechanism of injury. Multivariate logistic regression analysis was used to predict the impact of BMI on outcome scores. A total of 77 patients (72.7% male) were included with a mean age at the time of injury of 29.4 ± 11.0 years and a mean BMI of 30.5 ± 9.4 kg/m2. The mean length of follow-up was 7.4 years. For each 10 kg/m2 increase in BMI, there is a 0.9-point decrease in Tegner activity scale (p = 0.001), a 5-point decrease in Knee Injury and Osteoarthritis Outcome Score (KOOS)-pain (p = 0.007), a 5-point decrease in KOOS-ADL (p = 0.003), a 10-point decrease in KOOS-QOL (p = 0.002), and an 11-point decrease in KOOS-Sport (p = 0.002). There were no significant correlations with BMI and Pain Catastrophizing Scale or Patient Health Questionnaire scores. Increasing BMI has a negative linear relationship with mid- to long-term clinical outcomes including pain, ability to perform activities of daily living, quality of life, and ability to perform more demanding physical activity after MLKI. BMI does not appear to have a significant relationship with knee swelling and mechanical symptoms or patients' mental health.

Anterolateral Radial Meniscus Tear Repair using Traction Suture and Super-Hashtag Technique.

Radial meniscus tears occur commonly as traumatic tears in younger patients, as well as in association with concomitant degenerative changes. Traditional management of these tears has centered around partial meniscectomy; however, there has been a more recent trend toward preserving the meniscus and attempting repair. Because of the gapping and displacement that frequently occurs with these tears, repair is often challenging and is done under high amounts of tension. The following article describes a technique using a traction suture to aid in maintaining reduction throughout repair. This is followed by the use of a combination of techniques to form a "super-hashtag" configuration of both vertical and horizontal mattress sutures, leading to a secure repair under little tension.

Horizontal Cleavage Tear Meniscal Repair Using All-Inside Circumferential Compression Sutures.

Horizontal cleavage meniscus tears occur more frequently in older patient populations with degenerative changes within the meniscus. Traditionally, they have been managed with nonsurgical interventions or with partial meniscectomy. As increasing evidence demonstrates the link between partial meniscectomy and progressive osteoarthritis with these types of tears, as well as worse long-term outcomes and reduced cost savings, surgical repair of horizontal cleavage meniscal tears has increased in appropriate patients. This technique article highlights the evaluation, indications, and preferred repair technique for horizontal cleavage tears in appropriately selected patients.

Incidence, Common Pathogens, and Risk Factors for Infection after Primary Anterior Cruciate Ligament Reconstruction: A Systematic Review.

We sought to assess the current literature to present a comprehensive summary of the incidence, common pathogens, and risk factors for infection after anterior cruciate ligament (ACL) reconstruction. PubMed, CINAHL, EMBASE, and Scopus databases were searched for relevant studies reporting on infection after ACL reconstruction. Two reviewers independently screened the extracted studies for adherence to inclusion and exclusion criteria. Studies were selected if they reported on the incidence of infection, pathogens cultured from infected knees, or risk factors for infection after primary ACL reconstruction. Exclusion criteria consisted of studies with fewer than 100 patients or studies that included revision ACL reconstruction. Fifty studies met the inclusion and exclusion criteria, reporting on a total of 316,214 ACL reconstructions. Included studies evaluated between 123 and 104,255 patients. The overall incidence of infection was 0.60% (0.15-2.44%). The most common pathogens were Staphylococcus aureus, S. epidermidis, and coagulase-negative Staphylococci. Five studies reported that the use of hamstring autograft was a statistically significant risk factor for infection after ACL reconstruction, thus making hamstring autograft the most commonly reported risk factor. Other reported risk factors included male sex, use of immuno-suppressive medications or intraarticular steroid injections, prior knee surgery, and diabetes. Systematic review of the literature revealed that infection after ACL reconstruction remains an infrequent event with an incidence of 0.60% (0.15-2.44%). Furthermore, the most common pathogens are from the Staphylococcus genus of bacteria, comprising 84% of all culture-positive infections. Multiple risk factors have been reported for ACL reconstruction; however, statistical significance varied across studies. Together, these findings may help guide physicians in the prevention and treatment of infection after ACL reconstruction.

Predictors of Return to Activity at 2 Years After Anterior Cruciate Ligament Reconstruction Among Patients With High Preinjury Marx Activity Scores: A MOON Prospective Cohort Study.

BACKGROUND: Predictors of return to activity after anterior cruciate ligament reconstruction (ACLR) among patients with relatively high preinjury activity levels remain poorly understood. PURPOSE/HYPOTHESIS: The purpose of this study was to identify predictors of return to preinjury levels of activity after ACLR, defined as achieving a Marx activity score within 2 points of the preinjury value, among patients with Marx activity scores of 12 to 16 who had been prospectively enrolled in the Multicenter Orthopaedic Outcomes Network (MOON) cohort. We hypothesized that age, sex, preinjury activity level, meniscal injuries and/or procedures, and concurrent articular cartilage injuries would predict return to preinjury activity levels at 2 years after ACLR. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: All unilateral ACLR procedures from 2002 to 2008 performed in patients enrolled in the MOON, with preinjury Marx activity scores ranging from 12 to 16, were evaluated with a specific focus on return to preinjury activity levels at 2 years postoperatively. Return to activity was defined as a Marx activity score within 2 points of the preinjury value. The proportion of patients able to return to preinjury activity levels was calculated, and multivariable modeling was performed to identify risk factors for patients' inability to return to preinjury activity levels. RESULTS: A total of 1188 patients were included in the final analysis. The median preinjury Marx activity score was 16 (interquartile range, 12-16). Overall, 466 patients (39.2%) were able to return to preinjury levels of activity, and 722 patients (60.8%) were not able to return to preinjury levels of activity. Female sex, smoking at the time of ACLR, fewer years of education, lower 36-Item Short Form Health Survey Mental Component Summary scores, and higher preinjury Marx activity scores were predictive of patients' inability to return to preinjury activity levels. Graft type, revision ACLR, the presence of medial and/or lateral meniscal injuries, a history of meniscal surgery, the presence of articular cartilage injuries, a history of articular cartilage treatment, and the presence of high-grade knee laxity were not predictive of a patient's ability to return to preinjury activity level. CONCLUSION: At 2 years after ACLR, most patients with high preinjury Marx activity scores did not return to their preinjury level of activity. The higher the preinjury Marx activity score that a patient reported at the time of enrollment, the less likely he/she was able to return to preinjury activity level. Smoking and lower mental health at the time of ACLR were the only modifiable risk factors in this cohort that predicted an inability to return to preinjury activity levels. Continued effort and investigation are required to maximize functional recovery after ACLR in patients with high preinjury levels of activity.

Horizontal Cleavage Meniscus Tears: Biomechanics, Indications, Techniques, and Outcomes.

¼ Accounting for up to 24% of all meniscus tears, horizontal cleavage tears (HCTs) are a common pathology orthopaedic practitioners should be comfortable managing.¼ Historically, HCTs were treated with partial meniscectomy; however, recent studies have demonstrated that these procedures have an adverse biomechanical effect, while HCT repairs restore the knee's natural biomechanics.¼ Indications for the surgical repair of HCTs remain disputed, but surgery is generally considered for young, active patients and older patients without significant concomitant osteoarthritis.¼ Early clinical findings surrounding HCT repair are promising. They suggest that this treatment adequately restores meniscus mechanics, leads to good knee functional outcomes, and results in a high likelihood of return to preinjury activity levels.

Posterior Meniscal Root Repair With Transtibial Double Tunnel Pullout Technique and Anchor Fixation.

Meniscus root tears are tears that occur within 1 cm of the meniscus root attachment to the tibia. If not repaired, root tears will lead to altered knee biomechanics and accelerated degenerative changes in the knee. In this surgical technique, we demonstrate repair of a meniscus root tear with an all-inside suture repair of the posterior meniscus that is then passed through 2 transtibial tunnels and then fixed with an anchor. After surgery, patients are non-weightbearing for 4 weeks and can return to activity by 6 months.

Patella alta and increased TT-TG distance do not adversely affect patient-reported outcomes following isolated MPFL reconstruction: A systematic review.

OBJECTIVES: To analyze the effect of patellofemoral anatomical variations (patella alta, increased tibial tubercle-trochlear groove [TT-TG] distance, and trochlear dysplasia) on clinical outcomes after isolated medial patellofemoral ligament (MPFL) reconstruction. METHODS: A comprehensive search from PubMed, Embase, and the Cochrane Library databases was conducted to identify studies that compared outcomes based on the presence or absence of patella alta, elevated tibial tubercle-trochlear groove (TT-TG) distance, and/or trochlear dysplasia. Exclusion criteria included reviews and meta-analyses, studies that included patients who underwent associated bony procedures, and those reporting outcomes after isolated MPFL reconstruction with no comparison between varying anatomical groups. RESULTS: After application of selection criteria, 19 studies were included. Patella alta was not predictive of failure or poorer outcomes among 13 studies; however, 2 studies demonstrated poorer patient-reported outcome scores and/or higher failure rates with increasing patellar height. Increasing TT-TG distance demonstrated a statistically significant correlation with poorer outcomes in only one study, whereas 12 other studies showed no association. Trochlear dysplasia resulted in worse outcomes and greater failure rates in 6 studies, while 10 studies showed no statistically significant correlation between trochlear dysplasia and postoperative outcomes. CONCLUSION: Patella alta and increased TT-TG distance did not adversely affect outcomes following isolated MPFL reconstruction in the preponderance of reviewed studies. Data are mixed regarding the impact of trochlear dysplasia on the outcomes of isolated MPFL reconstruction. LEVEL OF EVIDENCE: IV.

Influence of Staphylococcus epidermidis on Collagen Crimp Patterns of Soft Tissue Allograft.

BACKGROUND: Postoperative infections, commonly from Staphylococcus epidermidis, may result in anterior cruciate ligament graft failure and necessitate revision surgery. In biomechanical studies, S. epidermidis has been shown to establish biofilms on tendons and reduce graft strength. PURPOSE/HYPOTHESIS: The goal of this study was to determine the effect of bacterial bioburden on the collagen structure of tendon. It was hypothesized that an increase in S. epidermidis biofilm would compromise tendon crimp, a pattern necessary for mechanical integrity, of soft tissue allografts. STUDY DESIGN: Controlled laboratory study. METHODS: Cultures of S. epidermidis were used to inoculate tibialis anterior cadaveric tendons. Conditions assessed included 5 × 105 colony-forming units or concentrated spent media from culture (no living bacteria). Incubation times of 30 minutes, 3 hours, 6 hours, and 24 hours were utilized. Second-harmonic generation imaging allowed for visualization of collagen autofluorescence. Crimp lengths were determined using ImageJ and compared based on incubation time. RESULTS: Incubation time positively correlated with increasing S. epidermidis bioburden. Both fine and coarse crimp patterns lengthened with increasing incubation time. Significant coarse crimp changes were observed after only 30-minute incubations (P < .029), whereas significant fine crimp lengthening occurred after 6 hours (P < .0001). No changes in crimp length were identified after incubation in media lacking living bacteria. CONCLUSION: The results of this study demonstrate that exposure to S. epidermidis negatively affects collagen crimp structure. Structural alterations at the collagen fiber level occur within 30 minutes of exposure to media containing S. epidermidis. CLINICAL RELEVANCE: Our study highlights the need for antimicrobial precautions to prevent graft colonization and maximize graft mechanical strength.

Qualitative visual assessment of the J-sign demonstrates high inter-rater reliability.

OBJECTIVES: To assess the inter- and intra-rater reliability of the classification of the J-sign as "large" versus "small or none" as compared to another two-level system ("present" versus "absent") and a three-level system ("large," "small," or "none") and to identify anatomical and patient factors associated with the presence of a large J-sign. METHODS: Forty patients (40 knees) with recurrent patellar instability were prospectively enrolled and recorded on video actively extending their knee while seating. Four raters classified patellar tracking on two separate occasions using three systems: 1) two groups: J-sign versus no J-sign; 2) three groups: large J-sign, small J-sign, or no J-sign; and 3) two groups: large J-sign versus small or no J-sign. The intra- and inter-rater reliability of each system was assessed using kappa statistics. Anatomical (trochlear dysplasia, tibial tubercle-trochlear groove (TT-TG) distance, patellar height) and patient (Beighton score) factors as well as Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales were compared between patients with a large J-sign and patients with a small or no J-sign. RESULTS: Inter- and intra-rater reliability were found to be highest with the two-level classification system of a large J-sign versus a small or no J-sign (inter-rater kappa â€‹= â€‹0.76, intra-rater kappa â€‹= â€‹0.75). Patients with a large J-sign had more severe trochlear dysplasia as assessed with the sulcus angle (p â€‹= â€‹0.042) and were more likely to have a tight lateral retinaculum (p â€‹= â€‹0.032) and an elevated Beighton score (p â€‹= â€‹0.009). No significant differences in KOOS subscales were noted based on the presence of a large J-sign versus a small J-sign or no J-sign. CONCLUSION: Qualitative visual assessment of patellar tracking with the J-sign demonstrates substantial inter- and intra-rater reliability, particularly when utilizing a two-group classification system to identify knees with a large J-sign. Patients with a large J-sign demonstrate an increased incidence of a tight lateral retinaculum, generalized ligamentous laxity, and trochlear dysplasia. LEVEL OF EVIDENCE: Level III - cross-sectional study.

More Is Not Merrier: Increasing Numbers of All-Inside Implants Do Not Correlate with Higher Odds of Revision Surgery.

The purpose of this study was to evaluate the relationship between the number of all-inside meniscal repair implants placed and the risk of repair failure. We hypothesized that the use of higher numbers of all-inside meniscus repair implants would be associated with increased failure risk. A retrospective chart review identified 351 patients who underwent all-inside meniscus repair between 2006 and 2013 by a sports medicine fellowship-trained orthopaedic surgeon at a single institution. Patient demographics (age, body mass index [BMI], sex) and surgical data (number of implants used, concomitant anterior cruciate ligament reconstruction [cACLR], and tear type/size/location) were recorded. Patients who received repairs in both menisci or who had follow-up < 1-year postoperatively were excluded. Repair failure was identified through chart review or patient interviews defined as a revision surgery on the index knee such as partial meniscectomy, total knee arthroplasty, meniscus transplant, or repeat repair. Logistic regression modeling was utilized to evaluate the relationship between the number of implants used and repair failure. A total of 227 all-inside meniscus repairs were included with a mean follow-up of 5.0 ± 3.0 years following surgery. Repair failure was noted in 68 knees (30.3%)-in 28.1% of knees with fewer than four implants and in 35.8% of knees with four or more implants (p = 0.31). No significant increase in failure was observed with increasing number of all-inside medial (odds ratio [OR]: 1.15; 95% confidence interval [CI]: 0.79-1.7; p = 0.46) or lateral (OR: 0.86; 95% CI: 0.47-1.57; p = 0.63) implants after controlling for patient age, BMI, cACLR, tear type, or size. Tears of the lateral meniscus located in the red-white and white-white zones had lower odds of failure (OR: 0.14; 95% CI: 0.02-0.88; p = 0.036) than tears within the red-red zone, and patients with cACLR had lower odds of repair failure (OR: 0.40; 95% CI: 0.18-0.86, p = 0.024) than those without. The number of all-inside implants placed during meniscus tear repair did not affect the likelihood of repair failure leading to reoperation after controlling for BMI, age, tear type, size, location, and cACLR. LEVEL OF EVIDENCE: III.

Failure of osteochondral lesions using bioabsorbable fixation in the adolescent patient: a case report.

Injury to the chondral surface and subchondral bone can be due to osteochondritis dissecans or traumatic injury. These lesions can lead to pain, swelling, and mechanical symptoms causing functional impairments for patients. Treatment can include nonoperative management or surgical intervention including internal fixation. Internal fixation can be performed through multiple methods including the use of bioabsorbable screw fixation, though there is concern for potential early failure of this method. We present three cases of osteochondral lesions treated with internal fixation with bioabsorbable screws, which experienced early failure of the bioabsorbable screws, leading to failure of fixation and requiring revision surgery with advanced cartilage restoration procedures. All patients had resolution of their symptoms and improved function postoperatively. While the use of bioabsorbable screw fixation can potentially decrease cost and morbidity, their mechanical properties may increase the risk of failure before lesion healing. We advocate caution with the use of these screws for the treatment of unstable osteochondritis dissecans lesion and recommend careful patient selection and meticulous surgical technique to avoid failure of fixation of these lesions.

An implantable shock absorber yields an 85% survival-from-arthroplasty rate through 5 years in working-age patients with medial compartment knee osteoarthritis.

PURPOSE: To evaluate the 5-year rate of survival without undergoing arthroplasty or high tibial osteotomy (HTO) in subjects with mild-to-moderate medial compartment knee osteoarthritis (OA) who were treated with an implantable shock absorber (ISA) system. METHODS: Three prospective, sequential, multicenter, international, single-arm clinical trials were conducted comprising subjects who received an ISA for symptomatic medial knee OA after failing ≥ 6 months of conservative therapy. Study outcomes were analyzed cumulatively and by enrollment group when all subjects' follow-up data exceeded the 2-year threshold after ISA implantation. Primary outcome was survival rate without conversion to arthroplasty/HTO. Secondary outcomes were changes in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores after ISA implantation. RESULTS: All 171 enrolled subjects (age 51 ± 9 years, body-mass index 28.5 ± 3.5 kg/m2, 38% female; study knee Kellgren-Lawrence score 2.7 ± 0.9 points) were followed for a minimum of 2, and up to 5, years after device implantation. Overall, 90.6% (155/171) of subjects survived without requiring arthroplasty/HTO at last follow-up (mean 3.2 ± 1.6 years). The Kaplan-Meyer median 3- and 5-year survival-without-arthroplasty point estimates were 89.8% (95% CI 86.5‒95.7%) and 84.9% (95% CI 75.1‒91.1%), respectively. The median 3-year estimated survival rate for the most recent study (n = 81) was 97.3%. The mean WOMAC Pain score decreased 71% from baseline to last follow-up after ISA implantation, from 58 ± 13 to 16 ± 17 points (p < 0.0001). The Function score improved 69%, decreasing from 56 ± 18 to 17 ± 17 points (p < 0.0001). CONCLUSIONS: In younger patients with mild-to-moderate symptomatic medial compartment knee OA, implantation of the ISA device resulted in a 5-year survival rate of 85% from undergoing arthroplasty or HTO. The ISA system may be an effective treatment option for working-age patients with medial knee OA who are not candidates for or do not desire more invasive surgical approaches. LEVEL OF EVIDENCE: II.

Going beyond Binary: Rapid Identification of Protein-Protein Interaction Modulators Using a Multifragment Kinetic Target-Guided Synthesis Approach.

Kinetic target-guided synthesis (KTGS) is a powerful screening approach that enables identification of small molecule modulators for biomolecules. While many KTGS variants have emerged, a majority of the examples suffer from limited throughput and a poor signal/noise ratio, hampering reliable hit detection. Herein, we present our optimized multifragment KTGS screening strategy that tackles these limitations. This approach utilizes selected reaction monitoring liquid chromatography tandem mass spectrometry for hit detection, enabling the incubation of 190 fragment combinations per screening well. Consequentially, our fragment library was expanded from 81 possible combinations to 1710, representing the largest KTGS screening library assembled to date. The expanded library was screened against Mcl-1, leading to the discovery of 24 inhibitors. This work unveils the true potential of KTGS with respect to the rapid and reliable identification of hits, further highlighting its utility as a complement to the existing repertoire of screening methods used in drug discovery.