Observations on the growth of loose bodies in joints

In Vitro Evaluation of Lateral Femur Condyle Free Chondral Fragment Swelling after Soaking in Normal Saline

OBJECTIVE

After traumatic knee injuries, chondral fragments can avulse off bone with the progeny fragment becoming a loose body. The loose fragment may be larger than expected when trying to surgically repair the fragment back to its original site. The purpose of this study was to determine whether a loose chondral fragment from the lateral femur condyle would increase in size and weight after soaking in normal saline (NS) for 14 days.

DESIGN

Twelve 6-mm OAT (osteoarticular transfer) plugs were harvested from 6 cadaver knees on the lateral femoral condyle to simulate a chondral fragment. The chondral fragments were then placed inside an airtight specimen container with NS (0.9% sodium chloride) and were measured over 14 days.

RESULTS

After 14 days, the chondral fragments showed no increase in diameter as they measured an average of 5.567 ± 0.448 mm on Day 1 and 5.702 ± 0.253 mm on Day 14 (P = 0.183). The chondral fragments showed an increase in mass from an average of 0.058 ± 0.012 g on Day 1 to 0.073 ± 0.012 g on Day 14 (P < 0.001) and an increase in thickness from an average of 2.038 ± 0.346 mm on Day 1 to 2.229 ± 0.297 mm on Day 14 (P = 0.033).

CONCLUSIONS

Chondral fragments in NS increase in mass and thickness over time, but do not change in diameter. When surgeons are evaluating loose chondral fragments for fixation, they should consider that these fragments may appear thicker than the recipient location.

Imaging evaluation of extraarticular posterior loose bodies in varus ankle osteoarthritis

Purpose: Multiple loose bodies (LBs) are often found in patients with varus ankle osteoarthritis (OA). This study aimed to investigate the characteristics of extra-articular posterior ankle LBs in patients with varus ankle OA. We also sought to determine whether there were variations in the characteristics of LBs according to the degree of ankle OA. Methods: We retrospectively reviewed 50 patients who had appeared posterior extraarticular LBs on preoperative ankle imaging among the patients who underwent operative treatment for varus ankle OA from March 2011 to February 2023. We categorized the entire patient cohort into four groups according to the degree of ankle arthritis (Takakura stage II, IIIA, IIIB, and IV). Size, number, and location of LBs were evaluated using preoperative computed tomography and magnetic resonance imaging. Results: 142 LBs were identified (mean size: 11.5 mm); 76.8% were located within the flexor hallucis longus (FHL) tendon sheath, 20.4% in the posterior recess, and 2.8% in the flexor digitorum longus tendon sheath. Average LB size was significantly larger in Takakura stage IIIB and IV patients (p < .05), and the LB number was significantly lower in stage II patients (p = .013). Conclusion: Extra-articular posterior LBs in varus ankle OA are predominantly located within the FHL tendon sheath and were larger in Takakura stages IIIB and IV patients.Level of Evidence: Level III. Retrospective comparative study.

Assessment and Management of Loose Bodies in the Knee Joint and Related Disease: A Narrative Review

BACKGROUND

Loose bodies are frequently encountered during clinical activity and are a common finding during knee arthroscopy. Usually, treatment consists of the removal of loose bodies, which can be challenging even for experienced surgeons. The excision alone is not always the complete treatment, because loose bodies are generally secondary to other diseases that can cause persistent symptoms with the risk of new loose body formation. The aim of this narrative review is to show the clinical, imaging, and arthroscopic evaluation of loose bodies in order to plan optimal treatment.

METHODS

A comprehensive search of PubMed was conducted to find the most recent and relevant studies investigating aetiopathogenesis, the assessment tools, and the therapeutic strategies for loose bodies in the knee and their related diseases.

RESULTS

When dealing with a loose body, the first issue is the evaluation of the intra-articular fragment (location, size, number, symptoms) and its aetiopathogenesis by identifying the underlying pathology (e.g., osteochondritis dissecans, osteoarthritis, chondral defect, tumour-like lesions, rheumatoid arthritis, etc.). In the case of symptomatic intra-articular loose bodies, treatment consists of fragment removal and the management of related diseases (e.g.., lifestyle modification, physiotherapy, pharmacological, and surgical treatment).

CONCLUSION

Loose bodies are not separate entities and in addition to their pathological aspect, must be evaluated within the context of the underlying disease. Correct assessment and comprehensive management allow for relief of symptomatology and prevention of loose body formation by removal and treatment of the associated diseases.

Histologic evaluation of osteochondral loose bodies and repaired tissues after fixation

PURPOSE

The purpose of this study was to evaluate histologic changes in osteochondral loose bodies in the rabbit knee joint and histologic changes in repaired tissue after fixation of osteochondral loose bodies following isolation periods of varying length.

METHODS

We harvested osteochondral fragments from the patellar groove in rabbit knee joints and left them in the lateral gutters of the joints for periods of varying duration to create osteochondral loose bodies. We then evaluated histologic and immunohistochemical changes within these loose bodies. Next, we fixed osteochondral loose bodies that had been isolated for various periods within the joints to the osteochondral defect in the patellar groove. Twelve weeks after fixation, repaired tissues were evaluated histologically and immunohistochemically, and results were analyzed according to the varying isolation periods of fragments.

RESULTS

Extracellular matrix and type II collagen expression of osteochondral loose bodies deteriorated with increased duration of fragment isolation periods. A significantly negative correlation was noted between length of isolation periods and histologic grading scores. After osteochondral loose bodies had been fixed, repaired tissues deteriorated significantly in accordance with duration of fragment isolation periods. However, in some cases, even when osteochondral fragments had been isolated for 12 weeks, repaired tissues showed dense extracellular matrix stained by safranin O and abundant type II collagen expression, which indicated regeneration of the cartilage layer.

CONCLUSIONS

Osteochondral loose bodies and repaired tissues deteriorated after they were fixed to osteochondral defects. Although a direct correlation was noted between isolation periods of fragments and time to their deterioration, some osteochondral loose bodies showed regeneration of cartilage after fixation.

CLINICAL RELEVANCE

Clinically, reduction of osteochondral loose bodies should be performed as early as possible, if these can be found. However, even if the fragment seems to be old, fragment fixation is worthy of consideration.

The development of posttraumatic arthritis after articular fracture

Posttraumatic arthritis (PTA) is one of the most frequent causes of disability after trauma involving weight-bearing joints and is estimated to be responsible for approximately 10% of the 21 million Americans who have osteoarthritis. Despite a number of similarities in the pathology and end-stage disease of PTA with primary osteoarthritis, the mechanisms involved in the onset and progression of joint degeneration after articular fracture are poorly understood. The largest area of study regarding articular fractures and the development of arthritic changes has focused on the role of adequate surgical reduction of the articular surfaces. However, it is now apparent that a number of complex and interacting biomechanical, biochemical, and, possibly, genetic factors contribute to the development of osteoarthritic changes in the joint after joint trauma, ranging from the cell and molecular level to the joint and systemic level. In this paper, we discuss the potential roles of the initial impact and fracture as well as the subsequent alterations in joint loading, biomechanical and metabolic properties of the cartilage, local and systemic inflammatory cytokines, and viability of chondrocytes in the progression of PTA. An improved understanding of the mechanisms involved in the development of PTA will hopefully lead to the improvement of surgical and nonsurgical therapies for this disease.

MR Arthrography of the Knee: How, Why, When

MR arthrography combines the techniques of arthrography with MR imaging to benefit from the added imaging information afforded by intra-articular distention. This article reviews technical considerations for MR arthrography, potential complications, indications, pitfalls in imaging diagnosis, and commonly encountered pathology. It is an elegant study that can offer precise diagnostic information in the appropriate clinical setting.