Understanding the Glenoid Avulsion of the Glenohumeral Ligaments as a Cause of Shoulder Instability: Surgical and Postsurgical Management.

In adolescents and young adults, instability is a common shoulder pathology with a myriad of coexisting soft tissue and bony lesions. When evaluating a patient for the cause of instability, care must be given to assess for the infrequent lesions, including glenoid avulsion of the glenohumeral ligaments. This case example illustrates key points in the diagnosis, surgical, and postsurgical management of this less common cause of anterior shoulder instability.

Bilateral, Atraumatic Proximal Tibiofibular Joint Instability Treated With Suspensory Button Fixation.

Proximal tibiofibular joint (PTFJ) instability is a rare cause of lateral-sided knee pain. The authors present a case of bilateral, symptomatic PTFJ instability with peroneal nerve dysfunction in an active 16-year-old female athlete. This was addressed with peroneal nerve decompression and PTFJ stabilization using a suspensory button fixation system. This provides an alternative treatment from historical methods such as PTFJ fusion or re-approximation of the joint with tendon through bone tunnels. The surgical technique, as well as potential treatment challenges, is described in detail. The purpose of this report is to highlight PTFJ instability as a cause of lateral-sided knee pain to avoid misdiagnosis and delay in appropriate treatment. This patient had significant improvement in pain and decreased neurologic symptoms after the stabilization and nerve decompression. She was able to return to high-level activity. [Orthopedics. 2017; 40(6):e1107-e1111.].

Open Reduction Internal Fixation of Isolated Chondral Fragments Without Osseous Attachment in the Knee: A Case Series.

BACKGROUND: Isolated chondral fractures of the knee are a rare and challenging problem, typically occurring with an acute traumatic event such as dislocation of the patella or ligamentous injury. Historically, repair of unstable chondral fragments without osseous attachment has not been recommended due to concerns about the limited healing potential of cartilage. PURPOSE: To describe a technique for fixation of large isolated chondral fractures of the knee and present 3 cases where large chondral fragments without osseous attachment were fixed successfully with chondral darts and biologic adhesive. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The senior author reviewed his case logs for all patients on whom he performed open reduction and internal fixation on large isolated cartilage fragments without osseous attachment. Three were extracted from his review. The clinical and radiographic outcomes were retrospectively reviewed. RESULTS: Successful results and complete healing was obtained in all 3 patients. This procedure can be done in the setting of concurrent injury, such as anterior cruciate ligament tear, using single- or multistaged chondral repair and ligament reconstruction techniques. CONCLUSION: Isolated chondral fragment repair techniques provide the orthopaedic surgeon an additional option for treating these challenging injuries. Primary fixation can be accomplished for what have been historically considered "unsalvageable" fragments.

Muscle changes in aging: understanding sarcopenia.

UNLABELLED: Muscle physiology in the aging athlete is complex. Sarcopenia, the age-related decrease in lean muscle mass, can alter activity level and affect quality of life. This review addresses the microscopic and macroscopic changes in muscle with age, recognizes contributing factors including nutrition and changes in hormone levels, and identifies potential pharmacologic agents in clinical trial that may aid in the battle of this complex, costly, and disabling problem. LEVEL OF EVIDENCE: Level 5.

Glenoid avulsion of the glenohumeral ligaments as a cause of recurrent anterior shoulder instability.

Although the Bankart lesion is accepted as the primary pathology responsible for recurrent shoulder instability, recognition of other soft-tissue lesions has improved the surgical treatment for this common problem. Whereas humeral avulsion of the glenohumeral ligaments has been acknowledged as a cause of anterior shoulder instability, we have not found any reported cases of glenoid avulsion of the glenohumeral ligaments. We describe 3 cases of recurrent anterior shoulder instability due to glenoid avulsion of the glenohumeral ligaments. The avulsed ligaments were repaired to the labrum and glenoid, restoring the glenohumeral ligament-labral complex.

Current concepts in pediatric and adolescent arthroscopy.

Arthroscopy continues to grow as a treatment modality for pediatric and adolescent orthopaedic pathologies. In recent years arthroscopic procedures previously reserved for adult patients have become more frequently used in the treatment of younger individuals. Advancements in arthroscopic instrumentation including smaller arthroscopes and tools have made the constraint of smaller joint spaces in the pediatric and adolescent populations less of a limiting factor when addressing surgical options for care. This is valuable considering the consistent increase in pediatric sports- and activity-related injuries, of which many are treatable arthroscopically. Currently, arthroscopy is indicated for the treatment of various chronic and acute injuries of the shoulder, elbow, wrist, hip, knee, and ankle. This review aims to highlight the current literature regarding arthroscopy in this population while also offering treatment algorithms, rehabilitation guidelines, and surgical tips for various pathologies in pediatric and adolescent patients.

Catabolic responses of chondrocyte-seeded peptide hydrogel to dynamic compression.

This study investigated the role of matrix metalloproteases and aggrecanases during dynamic compression-induced aggrecan catabolism in chondrocyte-seeded self-assembling peptide hydrogel. One- to two-week-old bovine chondrocytes were encapsulated into peptide hydrogel and cultured for 14 days prior to the application of an alternate day loading protocol. Dynamic compression-induced aggrecan catabolism was explored by evaluating GAG loss to the culture medium, zymography for matrix metalloproteases (MMPs), gene expression of MMPs and ADAMTS proteases, and Western blot analysis for aggrecan fragments. The application of loading over 4 days increased GAG loss to the medium three- to four-fold relative to free-swelling controls. Zymogram analysis detected increased concentrations of latent MMP-9 and MMP-3 in the culture medium relative to free-swelling culture. Real-time PCR showed expression levels of MMPs and ADAMTS proteases in loaded samples that ranged from 2.5- to 95-fold higher than free-swelling culture. Aggrecan fragment analysis did not detect small (50-80 kDa) molecular weight fragments in free-swelling culture; however, dynamic compression samples contained 60-80 kDa fragments that were detected by both anti-G1 and NITEGE probes, demonstrating ADAMTS but not MMP degradation. These data suggest that partially mature cartilage tissue engineering constructs may be susceptible to catabolic degradation.

A biomechanical comparison of initial fixation strength of 3 different methods of anterior cruciate ligament soft tissue graft tibial fixation: resistance to monotonic and cyclic loading.

BACKGROUND: Tibial fixation of soft tissue grafts continues to be problematic in the early postoperative period after anterior cruciate ligament reconstruction. HYPOTHESIS: No differences exist for resistance to slippage of soft tissue grafts fixed with CentraLoc, Intrafix, or 35-mm bioabsorbable interference screws. STUDY DESIGN: Controlled laboratory study. METHODS: Bovine tibia and hoof extensor tendons were divided into 3 matched groups with 12 tibia and 12 extensor tendons in each group. Within each group, 6 specimens underwent monotonic loading to failure (1 mm/s), and 6 underwent cyclic loading (10,000 cycles, 125-325 N, 1 Hz). RESULTS: No statistically significant differences were noted in mean load to failure or stiffness. The mean load to failure (and stiffness) for the 3 types of fixation were as follows: bioabsorbable interference screw, 631.6 +/- 130.1 N (88.17 +/- 6.79 N/mm); Intrafix, 644.3 +/- 195.2 N (81.65 +/- 16.5 N/mm); and CentraLoc, 791.1 +/- 72.7 N (77.89 +/- 7.07 N/mm). The slippage rates under cyclic loading for the 3 types of fixation were bioabsorbable interference screw, 0.336 +/- 0.074 microm/cycle; Intrafix, 27.2 +/- 31.6 microm/cycle; and CentraLoc, 0.0355 +/- 0.0046 microm/cycle. In this model, CentraLoc proved statistically superior in resistance to cyclic loading compared with the bioabsorbable interference screw (P < .05) and Intrafix (P < .0001). The bioabsorbable interference screw proved statistically superior to Intrafix in resistance to cyclic loading (P < .05). CONCLUSIONS: In this bovine model, CentraLoc and bioabsorbable interference screws provided superior resistance to cyclic loading compared with Intrafix. CLINICAL RELEVANCE: CentraLoc and bioabsorbable interference screws showed superior resistance to cyclic loading, which may indicate an increased resistance to clinical failure.

The diagnosis of meniscus tears: the role of MRI and clinical examination.

Magnetic resonance imaging (MRI) and clinical examination are tools commonly used in the diagnosis of meniscus tears. It has been suggested routine MRI before therapeutic arthroscopy for clinically diagnosed meniscus tears will reduce the number and cost of unnecessary invasive procedures. We designed a systematic review of prospective cohort studies comparing MRI and clinical examination to arthroscopy to diagnosis meniscus tears. Thirty-two relevant studies were identified by a literature review. Careful evaluation by an experienced examiner identifies patients with surgically treatable meniscus lesions with equal or better reliability than MRI. MRI is superior when indications for arthroscopy are solely diagnostic. However, the methods by which such a clinician arrives at a conclusion have not been identified. To create an evidence-based algorithm for the diagnosis of a meniscus tear future investigations should prospectively assess the value of commonly used aspects of the patient history and meniscus tests. MRI is useful, but should be reserved for situations in which an experienced clinician requires further information before arriving at a diagnosis. Indications for arthroscopy should be therapeutic, not diagnostic in nature.

Mechanisms and kinetics of glycosaminoglycan release following in vitro cartilage injury.

OBJECTIVE: Acute joint injury leads to increased risk for osteoarthritis (OA). Although the mechanisms underlying this progression are unclear, early structural, metabolic, and compositional indicators of OA have been reproduced using in vitro models of cartilage injury. This study was undertaken to determine whether glycosaminoglycan (GAG) loss following in vitro cartilage injury is mediated by cellular biosynthesis, activation of enzymatic activity, or mechanical disruption of the cartilage extracellular matrix. METHODS: Immature bovine cartilage was cultured for up to 10 days. After 3 days, groups of samples were subjected to injurious mechanical compression (single uniaxial unconfined compression to 50% thickness, strain rate 100% per second). GAG release to the medium was measured, and levels were compared with those in location-matched, uninjured controls. The effects of medium supplementation with inhibitors of biosynthesis (cycloheximide), of matrix metalloproteinase (MMP) activity (CGS 27023A or GM 6001), and of aggrecanase activity (SB 703704) on GAG release after injury were assessed. RESULTS: GAG release from injured cartilage was highest during the first 4 hours after injury, but remained higher than that in controls during the first 24 hours postinjury, and was not affected by inhibitors of biosynthesis or degradative enzymes. GAG release during the period 24-72 hours postinjury was similar to that in uninjured controls, but the MMP inhibitor CGS 27023A reduced cumulative GAG loss from injured samples between 1 day and 7 days postinjury. Other inhibitors of enzymatic degradation or biosynthesis had no significant effect on GAG release. CONCLUSION: Injurious compression of articular cartilage induces an initially high rate of GAG release from the tissue, which could not be inhibited, consistent with mechanical damage. However, the finding that MMP inhibition reduced GAG loss in the days following injury suggests a potential therapeutic intervention.