Limited evidence for the usage of renin-angiotensin-aldosterone pathway blockers to prevent arthrofibrosis after total knee arthroplasty. A systematic review of clinical evidence.

Purpose: Despite advances in surgical techniques and rehabilitation protocols, arthrofibrosis following total knee arthroplasty (TKA) still has poor outcomes. In the last decade, attention has been focused on the pathogenesis and cascade of events leading to the development of fibrosis. Currently, one of the most promising approaches consists in the indirect antagonisation of transforming growth factor beta 1 () through the downregulation of the renin-angiotensin-aldosterone system (RAAS).

A Preliminary Study of Post-Market Bridge-Enhanced ACL Restoration (BEAR) Suggests Non-Inferior Short-Term Outcomes and Low Complications.

Background: To improve outcomes following anterior cruciate ligament (ACL) reconstruction, bridge-enhanced ACL restoration (BEAR) was introduced. Bridge-enhanced ACL restoration uses a collagen-based implant saturated with infused autologous blood to bridge the torn proximal and distal ACL fibers.

Purpose: We sought to analyze the short-term complications, clinical outcomes, and patient-reported outcome measures (PROMs) in patients undergoing BEAR outside of the initial clinical trials.

Treatment of Patellar Chondral Lesions With Concomitant Matrix-Induced Autologous Chondrocyte Implantation, Medial Patellofemoral Ligament Reconstruction, and Tibial Tubercle Osteotomy.

The US Food and Drug Administration approved matrix-induced autologous chondrocyte implantation (MACI) for use in the United States in 2016, and it has proven to be an effective treatment for articular cartilage defects in the knee. Concomitant patellar stabilization and realignment procedures, such as tibial tubercle osteotomy (TTO) and medial patellofemoral ligament (MPFL) reconstruction, are often performed with MACI to prevent further damage to the knee and to sustain the integrity of the cartilage repair. This Technical Note aims to describe MACI in the patella with concomitant patellar stabilization and realignment and to provide a treatment algorithm for when various simultaneous procedures are indicated.

Load Distribution After Serial Resection of the Posterior Horn of the Lateral Meniscus and Subsequent Meniscal Allograft Transplant: A Biomechanical Study.

Background: Data are lacking as to when a meniscal allograft transplant (MAT) may be biomechanically superior to a partially resected lateral meniscus.

Hypothesis: Lateral MAT using a bone bridge technique would restore load distribution and contact pressures in the tibiofemoral joint to levels superior to those of a partial lateral meniscectomy.

Study Design: Controlled laboratory study.

Management of patellar and trochlear cartilage lesions with matrix-induced autologous chondrocyte implantation in conjunction with patellofemoral realignment procedures improves patient-reported outcomes and magnetic resonance image appearance.

Objectives: The aim of this study is to evaluate the relationship between the achievement of clinically significant improvement in patient-reported outcome measures (PROMs) and the postoperative magnetic resonance image (MRI) appearance of matrix-associated chondrocyte implantation (MACI), in conjunction with patellofemoral realignment procedures, for the treatment of grade-IV chondral defects about the patellofemoral joint.

Methods: A retrospective review of patients undergoing MACI for grade-IV chondral defects of the patella or trochlea by a single sports-medicine-fellowship-trained surgeon from 2017 to 2020 was performed. Concomitant realignment procedures, including tibial tubercle osteotomy and medial patellofemoral ligament reconstruction, were also performed as needed.

Editorial Commentary: Both Osteochondral Allograft Transplantation and Autologous Chondrocyte Implantation Are Valuable Treatment Options for Patellofemoral Joint Cartilage Defects.

The patellofemoral (PF) joint is a challenging location to repair cartilage. Although both osteochondral allograft transplantation (OCA) and autologous chondrocyte implantation (ACI) are established as standard therapies for cartilage repair, most treatment algorithms continue to favor ACI for the PF joint, which shows a high rate of success. Today, however, OCA is a treatment of choice to revise prior failed PF cartilage repair.

Defining the minimal clinically important difference for IKDC and KOOS scores for patients undergoing tibial tubercle osteotomy for patellofemoral pain or instability.

Purpose: The aim of the present study is to define the minimal clinically important difference (MCID) for International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) for patients undergoing tibial tubercle osteotomy (TTO) for either (1) patellofemoral pain or (2) patellar instability.

Methods: Patients undergoing TTO for either patellofemoral pain or patellar instability by one of two sports medicine fellowship-trained surgeons at a single institution between September 2014 and May 2023 were included in the study. IKDC and KOOS scores were collected preoperatively and minimum 1 year postoperatively.

Initial Outcomes of Single versus Multiple-Plug Osteochondral Allograft Transplantation for Osteochondral Defects of the Knee: A Matched Cohort Analysis.

Although several prior studies have described the outcomes of osteochondral allograft (OCA) transplantation for single osteochondral lesions, there is a paucity of comparative data on outcomes of single versus multiple OCA transplants. We aimed to describe the initial outcomes of single-plug versus multiple-plug knee OCA transplants at a minimum of 1 year of follow-up. We hypothesized that there would be no difference in patient-reported outcome measures (PROMs) between patients undergoing single-plug and multiple-plug OCA transplants at a minimum of 1 year of follow-up.

Risk Factors for Atraumatic Medial Patellar Facet Lesions.

Background: Medial patellar facet lesions have been well-described in the setting of patellar instability. However, relatively little is known about risk factors for atraumatic medial patellar facet lesions.

Purpose/hypothesis: To identify clinical and radiographic risk factors for medial patellar facet lesions in patients without a history of trauma or patellar instability.

Decreased Effective Patellar Tendon Length following Distalization Tibial Tubercle Osteotomy without Patellar Tendon Tenodesis.

Background: Distalization tibial tubercle osteotomy (TTO) is an effective treatment for improving patellar height in patients with patella alta associated with patellofemoral instability and cartilage lesions. The addition of a patellar tendon tenodesis has been suggested; nonetheless, concerns exist regarding possible increased patellofemoral cartilage stresses.

Purpose: To evaluate pre- and postoperative patellar tendon length and alignment parameters on magnetic resonance imaging (MRI), as well as patient-reported outcome measures (PROMs) after distalization TTO without patellar tendon tenodesis.

Impact of Wiberg Patellar Type on Outcomes and Survival Following Cell-Based Cartilage Repair for Patellar Chondral Lesions at Midterm Follow-up.

Background: Cell-based cartilage repair procedures of the patellofemoral joint have less reliable outcomes than those of the tibiofemoral joint. No previous studies have evaluated the influence of patellar shape on cell-based cartilage repair outcomes. Patellar dysplasia may predispose patients to worse outcomes after cell-based cartilage repair.

Increased Host Bone Marrow Edema on 6-Month Magnetic Resonance Imaging Is a Risk Factor for Osteochondral Allograft Failure.

Purpose: To evaluate the presence of host bone marrow edema (BME) surrounding osteochondral allograft (OCA) plugs on routine 6-month postoperative magnetic resonance imaging (MRI) and to determine whether such BME is correlated with subsequent failure.

Methods: The present study was approved under our institutional review board-approved database (#2020-2123). We included patients who underwent cartilage repair with OCA for focal chondral and osteochondral defects of the distal femur by 2 senior surgeons between January 2016 and May 2021 with minimum 2-year follow-up.

Medial Meniscus Posterior Root Tears Lead to Changes in Joint Contact Mechanics at Low Flexion Angles During Simulated Gait.

Background: Previous biomechanical studies evaluating medial meniscus posterior root tears (MMPRTs) are limited to low loads applied at specified loading angles, which cannot capture the effects of MMPRTs during the multidirectional forces and moments placed across the knee during physiological activities.

Purpose: To quantify the effects of MMPRTs on knee joint contact mechanics during simulated gait.

Study Design: Controlled laboratory study.

Measure Twice, Cut Once: The Future of Digitally Planned Knee Osteotomies.

It is important to highlight the use of patient-specific cutting guides for knee joint osteotomies. Rationale, pitfalls, and planning of conventional osteotomy techniques are examined. The benefits of using patient-specific guides focusing on the potential for improved accuracy, efficiency, and safety are reviewed.

A modified Delphi consensus statement on patellar instability: part I.

Aims: The aim of this study was to establish consensus statements on the diagnosis, nonoperative management, and indications, if any, for medial patellofemoral complex (MPFC) repair in patients with patellar instability, using the modified Delphi approach.

Methods: A total of 60 surgeons from 11 countries were invited to develop consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest within patellar instability.

A modified Delphi consensus statement on patellar instability: part II.

Aims: The aim of this study was to establish consensus statements on medial patellofemoral ligament (MPFL) reconstruction, anteromedialization tibial tubercle osteotomy, trochleoplasty, and rehabilitation and return to sporting activity in patients with patellar instability, using the modified Delphi process.

Methods: This was the second part of a study dealing with these aspects of management in these patients. As in part I, a total of 60 surgeons from 11 countries contributed to the development of consensus statements based on their expertise in this area.

Multi-Surface Cartilage Defects about the Knee Treated with Cartilage Restoration Procedures Show Good Outcomes and Survivorship at Minimum 2-Year Follow-Up.

Objective: We aimed to evaluate the outcomes, survivorship, and complications following multi-surface cartilage procedures at minimum 2-year follow-up.

Design: Patients with either (1) single-surface osteochondral allograft transplantation (OCAT) with third-generation matrix-induced autologous cultured chondrocyte implantation (MACI) or particulated juvenile cartilage implantation (DeNovo), or (2) multiple-surface OCAT ± associated MACI/DeNovo procedures for grade IV chondral or osteochondral defects about the knee with minimum 2-year follow-up were analyzed. Patient-reported outcome measures (PROMs), including International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales, were obtained preoperatively and at minimum 2 years postoperatively.

Predilection of Patellofemoral Cartilage Lesions in Patients with Posterior Medial Meniscal Root Lesions.

Objective: The present study aims to compare the presence and severity of patellofemoral osteoarthritis between patients with root lesions and non-root lesions.

Design: A total of 102 patients were included in this study (51 root lesions and 51 non-root lesions). The root lesion cohort was matched to a non-root lesion cohort based on sex, body mass index, and age at the time of surgery.

Short-Term Outcomes of Concomitant Patellofemoral Arthroplasty and Medial Patellofemoral Ligament Reconstruction to Treat Concurrent Patellofemoral Arthritis and Patellar Instability.

The purpose of this study was to evaluate the efficacy of combined patellofemoral arthroplasty (PFA) and medial patellofemoral ligament (MPFL) reconstruction in patients with patellofemoral arthritis in the setting of concomitant patellar instability. Patients who underwent single-stage, combined PFA and MPFL reconstruction by a single surgeon at a tertiary-care orthopaedic center between 2016 and 2021 were identified. Postoperative radiographic and clinical outcomes at a minimum of 6 months were recorded using patient-reported outcome measures, including International Knee Documentation Committee (IKDC), Kujala, and VR-12.

Tibial Tubercle Osteotomy With Distalization for the Treatment of Patella Alta.

One of the most common osseous abnormalities associated with patellar instability and patellofemoral osteochondral disease is patella alta, characterized by an Insall-Salvati ratio ≥1.2 or a Caton-Deschamps Index ≥1.2.

Proximal bone block with distal screw trajectory improves mechanical stability during distalization tibial tubercle osteotomy.

Purpose: The purpose of this study was to quantify differences in mechanical stability of a wedge-shaped distalization tibial tubercle osteotomy (TTO) with a standard technique, versus a modified technique with use of a proximal bone block and distally angled screw trajectory.

Methods: Ten fresh-frozen cadaver lower extremity specimens (five matched pairs) were utilized. Within each specimen pair, one specimen was randomly assigned to undergo a standard distalization osteotomy fixed with two bicortical 4.

Patellofemoral arthroplasty conversion to total knee arthroplasty: An updated retrieval analysis and clinical outcomes.

Background: A prior retrieval analysis found high rates of infection after conversion of PFA to TKA, but was limited by a small sample size. The purpose of this study is to perform a retrieval analysis with clinical correlation on an expanded group of patients to better understand conversion of PFA to TKA.

Method: A retrospective review of an implant retrieval registry identified 62 conversions of PFA to TKA between 2004-2021.

Improved 2-Year Freedom from Arthroplasty in Patients with High-Risk SIFK Scores and Medial Knee Osteoarthritis Treated with an Implantable Shock Absorber versus Non-Operative Care.

Objective: Subchondral insufficiency fracture of the knee (SIFK) is associated with high rates of osteoarthritis (OA) and arthroplasty. The implantable shock absorber (ISA) is an extra-capsular implant that unloads the medial knee compartment. This study compared the 2-year freedom from arthroplasty rates in subjects with medial knee OA and SIFK when treated with an ISA versus a matched cohort of patients treated non-surgically.