Surgical restabilization reduces the progression of post-traumatic osteoarthritis initiated by ACL rupture in mice.

Objective: People who sustain joint injuries such as anterior cruciate ligament (ACL) rupture often develop post-traumatic osteoarthritis (PTOA). In human patients, ACL injuries are often treated with ACL reconstruction. However, it is still unclear how effective joint restabilization is for reducing the progression of PTOA.

Improving Technical Outcome in Osteochondral Allograft Transplantation of the Femoral Trochlea: The Role of Contoured Guides, Experience Level, Graft Size, and Graft Position.

Background: The use of coring instrumentation for osteochondral allograft (OCA) transplantation of the femoral trochlea is challenging due to the complex topography of this anatomical area.

Purpose: We sought to determine the effect of flat guides versus guides contoured to the surface of the trochlea on graft step-off in trochlear OCAs performed on a foam bone model. We also determined the effect of surgeon experience level and graft size on step-off.

Chondrocalcinosis and Osteoarthritis: A Literature Review.

Objective: The objective of this study was to review the literature on associations between chondrocalcinosis (CC) and osteoarthritis (OA) and to examine the role of colchicine, previously established as effective for calcium pyrophosphate deposition disease, in the treatment of OA.

Methods: A literature search for mechanistic and clinical studies published between 1990 and 2021 listed in PubMed was performed and studies were included if they examined the associations between OA and CC or colchicine using relevant search terms.

Results: Published evidence suggests significant radiographic and mechanistic associations between knee OA and knee CC, but there are only a limited number of studies demonstrating associations between OA and CC in the hips, hands, and ankles.

A Fresh Glimpse into Cartilage Immune Privilege.

The increasing prevalence of degenerative cartilage disorders in young patients is a growing public concern worldwide. Cartilage's poor innate regenerative capacity has inspired the exploration and development of cartilage replacement treatments such as tissue-engineered cartilages and osteochondral implants as potential solutions to cartilage loss. The clinical application of tissue-engineered implants is hindered by the lack of long-term follow-up demonstrating efficacy, biocompatibility, and bio-integration.

The immediate meniscal allograft transplantation achieved better chondroprotection and less meniscus degeneration than the conventional delayed transplantation in the long-term.

Purpose: The purpose of this study was to compare the long-term clinical and radiological outcomes between the immediate and delayed meniscus allograft transplantation (MAT).

Methods: Nine menisci were transplanted immediately after total meniscectomy (immediate group, IM), and 10 menisci were delayed transplanted in patients with the median of 35 months (range 9-92 months) after total meniscectomy (delayed group, DE). Patient's subjective clinical outcomes including VAS, IKDC, Lysholm and Tegner scores as well as muscle strength measures were compared.

Next Steps: Advocating for Women in Orthopaedic Surgery.

Orthopaedic surgery is the least diverse of all medical specialties, by both sex and race. Diversity among orthopaedic trainees is the lowest in medicine, and growth in percentage representation is the lowest of all surgical subspecialties. Women comprise only 6% of orthopaedic surgeons and 16% of orthopaedic surgery trainees.

Prognostic Factors to Determine Survivorship of Meniscal Allograft Transplant: A Systematic Review.

Background: There is much room for improvement and optimization of meniscal allograft survivorship.

Purpose: To understand prognostic factors for survivorship using evidence-based selection criteria in order to identify patients who would best benefit from meniscal allograft transplant (MAT).

Study Design: Systematic review; Level of evidence, 4.

Consensus on Rehabilitation Guidelines among Orthopedic Surgeons in the United States following Use of Third-Generation Articular Cartilage Repair (MACI) for Treatment of Knee Cartilage Lesions.

Objective: The aim of this study was to evaluate levels of consensus in rehabilitation practices following MACI (autologous cultured chondrocytes on porcine collagen membrane) treatment based on the experience of an expert panel of U.S. orthopedic surgeons.

Surgical and tissue engineering strategies for articular cartilage and meniscus repair.

Injuries to articular cartilage and menisci can lead to cartilage degeneration that ultimately results in arthritis. Different forms of arthritis affect ~50 million people in the USA alone, and it is therefore crucial to identify methods that will halt or slow the progression to arthritis, starting with the initiating events of cartilage and meniscus defects. The surgical approaches in current use have a limited capacity for tissue regeneration and yield only short-term relief of symptoms.

The medial epicondyle of the distal femur is the optimal location for MRI measurement of semitendinosus and gracilis tendon cross-sectional area.

Purpose: Graft diameter ≥ 8 mm reduces the risk of failure after anterior cruciate ligament reconstruction (ALCR) with hamstring tendon autograft. Pre-operative measurement of gracilis (GT) and semitendinosus (ST) cross-sectional area using MRI has been utilized but the optimal location for measurement is unknown. The main purpose of this study was to examine the cross-sectional areas of GT + ST at different locations and develop a model to predict whether a doubled hamstring graft of GT + ST will be of sufficient cross-sectional area for ACLR.

Effects of Micronized Cartilage Matrix on Cartilage Repair in Osteochondral Lesions of the Talus.

Background: The repair of osteochondral lesions remains a challenge due to its poor vascularity and limited healing potential. Micronized cartilage matrix (MCM) is dehydrated, decellularized, micronized allogeneic cartilage matrix that contains the components of native articular tissue and is hypothesized to serve as a scaffold for the formation of hyaline-like tissue. Our objective was to demonstrate that the use of MCM combined with mesenchymal stem cells (MSCs) can lead to the formation of hyaline-like cartilage tissue in a single-stage treatment model.

Bilateral lipoma arborescens -A proliferative case demonstrating progression in an adolescent male.

Case: We describe a case of extensive symptomatic bilateral lipoma arborescens of the knee in a 19-year-old man who suffered from recurrent knee effusions for many years. This patient had MRI evidence of progression of disease prior to arthroscopic intervention. He was treated with bilateral complete arthroscopic synovectomies, demonstrating no evidence of cartilage wear.

Editorial Commentary: PRP: Platelet-Rich Plasma or Promising but Rarely Proven?

Cost-utility analysis using a Markov decision model finds that platelet-rich plasma (PRP) is not cost-effective in rotator cuff repair because of no added outcomes benefit or improvement in retear rate according to best current evidence (Level I to III studies). To achieve the willingness-to-pay threshold, PRP would need to reduce rotator cuff retear rates. The authors have opened dialogue for us to determine what is the value and what should be the cost for PRP when it comes to rotator cuff repair.

The exercise-induced biochemical milieu enhances collagen content and tensile strength of engineered ligaments.

Exercise stimulates a dramatic change in the concentration of circulating hormones, such as growth hormone (GH), but the biological functions of this response are unclear. Pharmacological GH administration stimulates collagen synthesis; however, whether the post-exercise systemic milieu has a similar action is unknown. We aimed to determine whether the collagen content and tensile strength of tissue-engineered ligaments is enhanced by serum obtained post-exercise.

Estrogen inhibits lysyl oxidase and decreases mechanical function in engineered ligaments.

Women are more likely to suffer an anterior cruciate ligament (ACL) rupture than men, and the incidence of ACL rupture in women rises with increasing estrogen levels. We used an engineered ligament model to determine how an acute rise in estrogen decreases the mechanical properties of ligaments. Using fibroblasts isolated from human ACLs from male or female donors, we engineered ligaments and determined that ligaments made from female ACL cells had more collagen and were equal in strength to those made from male ACL cells.

Stimulation of the superficial zone protein and lubrication in the articular cartilage by human platelet-rich plasma.

Background: Platelet-rich plasma (PRP) contains high concentrations of autologous growth factors that originate from platelets. Intra-articular injections of PRP have the potential to ameliorate the symptoms of osteoarthritis in the knee. Superficial zone protein (SZP) is a boundary lubricant in articular cartilage and plays an important role in reducing friction and wear and therefore is critical in cartilage homeostasis.

Biological augmentation and tissue engineering approaches in meniscus surgery.

Purpose: The purpose of this review was to evaluate the role of biological augmentation and tissue engineering strategies in meniscus surgery. Although clinical (human), preclinical (animal), and in vitro tissue engineering studies are included here, we have placed additional focus on addressing preclinical and clinical studies reported during the 5-year period used in this review in a systematic fashion while also providing a summary review of some important in vitro tissue engineering findings in the field over the past decade.

Methods: A search was performed on PubMed for original works published from 2009 to March 31, 2014 using the term "meniscus" with all the following terms: "scaffolds," "constructs," "cells," "growth factors," "implant," "tissue engineering," and "regenerative medicine.

The effect of growth factors on both collagen synthesis and tensile strength of engineered human ligaments.

Growth factors play a central role in the development and remodelling of musculoskeletal tissues. To determine which growth factors optimized in vitro ligament formation and mechanics, a Box-Behnken designed array of varying concentrations of growth factors and ascorbic acid were applied to engineered ligaments and the collagen content and mechanics of the grafts were determined. Increasing the amount of transforming growth factor (TGF) β1 and insulin-like growth factor (IGF)-1 led to an additive effect on ligament collagen and maximal tensile load (MTL).

Clinical results of arthroscopic single-bundle transtibial posterior cruciate ligament reconstruction: a systematic review.

Background: Reconstruction of the posterior cruciate ligament has traditionally been performed using an arthroscopically assisted single-bundle transtibial technique. Unfortunately, clinical studies evaluating this procedure are rare. In addition, there are no pooled analyses evaluating the effectiveness of this procedure for isolated posterior cruciate ligament tears.

Gene expression of myogenic regulatory factors, nicotinic acetylcholine receptor subunits, and GAP-43 in skeletal muscle following denervation in a rat model.

Neuromuscular junction destabilization following nerve injury contributes to irreversible functional impairment. Myogenic Regulatory Factors (MRF's) including myoblast determination factor (MyoD), MRF-4, Myogenin, and myogenic factors-5 (myf-5), and Growth-associated protein 43 KDa (GAP43) regulate gene expression of nicotinic acetylcholine receptor (nAChR) subunits (alpha, beta, delta, gamma, and epsilon). We hypothesized that nerve injury induces altered gene expression of MRF's, nAChRs, and GAP-43 in the skeletal muscle which destabilize neuromuscular junctions.

Initial biomechanical properties of staple-anchor Achilles tendon allograft and interference screw bone-patellar tendon-bone autograft fixation for anterior cruciate ligament reconstruction in a cadaveric model.

Purpose: Anterior cruciate ligament (ACL) reconstruction is a common procedure that has a fairly high success rate. Despite such success, controversy exists with regard to fixation and graft type. The purpose of this study was to quantify the maximum load to failure for staple-anchor freeze-dried Achilles tendon allograft fixation compared with interference screw bone-pattelar tendon-bone autograft fixation at the time of insertion for ACL reconstruction.