Arthroscopic removal of loose bodies using the accessory portals in the difficult locations of the knee: a case series and technical note

Functional Imaging of the Knee-A Comprehensive Review

Knee pain is a common presenting problem in the general population. Radiographs and magnetic resonance imaging (MRI) are the cornerstones of imaging in current clinical practice. With advancements in technology, there has been increasing utilization of other modalities to evaluate knee disorders. Dynamic assessment utilizing computed tomography and portable ultrasounds have demonstrated the capacity to accurately assess and reproducibly quantify kinematics of knee disorders. Cartilage physiology can be evaluated with MRI. Emerging research has even demonstrated novel musculoskeletal applications of positron emission tomography to evaluate anterior cruciate ligament graft metabolic activity following reconstruction. As technology continues to evolve and traditional ways are improved upon, future comparative studies will elucidate the distinct advantages of the various modalities. Although radiology is still primarily an anatomic specialty, there is immense potential for functional imaging to be the standard of care. This review focuses on the most common musculoskeletal applications of functional imaging as well as future utilization.

Loose Bodies Found in the Human Intra-Articular Space Showed Characteristics Similar to Endochondral Bone Formation

OBJECTIVE

Loose bodies are free-floating tissues of cartilage and bone that can cause pain, swelling, the inability to straighten the knee, or intermittent locking of the knee. Loose bodies can arise from degenerative joint disease, flake fractures, osteochondritis dissecans, or chondromatosis. We hypothesized that loose bodies can be classified in stages with tissue characteristics similar to endochondral ossification.

DESIGN

Loose bodies were harvested from patients undergoing joint replacement. Samples were processed for histology, gene expression analysis, and micro-computed tomography (µCT). Cartilage- and bone-related genes and proteins were selected for immunofluorescence stainings (collagen type I, II, and X, SOX9 [SRY-box transcription factor 9], and MMP13 [matrix metalloproteinase 13]) and gene expression analysis (FN [fibronectin], COL1A1, COL2A1, COL10A1, SOX9, MMP13, and aggrecan [ACAN]).

RESULTS

Loose bodies were grouped in 4 stages: fibrous, (mineralized) cartilaginous, cartilage and bone, and bone. Hyaline-like cartilage tissue with Benninghoff arcades was present in stages 2 and 3. A transition from cartilaginous to mineralized tissue and bone trabecula was defined by an increase in COL1A1 and COL10A1 (stage 3 vs. 4: p = 0.047) positive area. Stage 4 showed typical trabecular bone tissue. The relative volume of calcified tissue (mineralized cartilage and bone tissue) decreased with stages (stages 1-2 vs. 3: p = 0.002; stage 1-2 vs. 4: p = 0.012). COL2A1 expression and stained area decreased from stages 1-2 to 4 (p = 0.010 and p = 0.004). ACAN expression decreased from stage 1-2 to stage 3 (p = 0.049) and stage 4 (p = 0.002).

CONCLUSION

Loose bodies show tissue characteristics similar to endochondral ossification. They are probably a relevant substrate for regenerative therapeutic interventions in joint disease.

The use of posteromedial portal for arthroscopic treatment of synovial chondromatosis of the knee: a case report

BACKGROUND

The synovial chondromatosis is an uncommon proliferative metaplastic process of the synovial cells that can develop in any synovial joint. An isolated primary chondromatosis of the posterior compartment of the knee is uncommon and few cases are reported in literature. Our purpose is to describe a rare case of primary chondromatosis of the knee posterior compartment and report the arthroscopic loose bodies excision through a difficult posteromedial portal, avoiding the use of the accessory posterior portal, most commonly reported for approaching this disease.

CASE PRESENTATION

We report a rare case of a 35-year-old Caucasian male patient with diagnosis of chondromatosis of the posterior knee compartment. The radiographs showed multiple loose bodies of the posterior compartment. The MRI revealed minimal synovial hypertrophy areas, multiple osteophytes in the intercondylar notch, and loose bodies in the posteromedial compartment. The CT allowed us to assess the bony structures, the morphology of the intercondylar notch, and the presence osteophytes of the medial and lateral femoral condyles. The CT images were crucial to plan how to reach the posterior compartments of the knee through a trans-notch passage. The patient underwent arthroscopic surgery using anteromedial, anterolateral, and posteromedial portals. The tunneling through the intercondylar osteophytes was performed to allow the arthroscope to pass trans-notch. To avoid additional accessory posterior portals, we used a 70° arthroscope to better explore the posterior knee compartment. The cartilage-like bodies were removed and synovectomy of the inflamed areas was performed. The clinical and radiological follow-up was 12 months and the patient showed excellent clinical outcomes, returning to his activities of daily living and sport activity.

CONCLUSION

Our case report highlights the importance of the arthroscopic approach to treat synovial chondromatosis, despite the involvement of the posterior compartment of the knee. An optimal preoperative imaging allows to plan for the proper surgical procedure even in patients with severe osteoarthritis. Moreover, the adoption of an intercondylar notch tunneling and a 70° arthroscope can help surgeons to better explore the posterior knee compartment, avoiding an accessory posterior trans-septal portal. Therefore, a synovectomy of the inflamed foci may be useful to prevent recurrence.

Arthroscopic Treatment of Popliteus Tendinitis Using the Accessory Portal

Introduction

This study aimed to evaluate the effect of arthroscopic treatment of popliteus tendinitis via an auxiliary extreme lateral approach and to investigate the pathogenesis and treatment of popliteus tendinitis.

Materials and Methods

From 2016 to 2020, arthroscopic popliteus tendon ablation was performed in 15 patients (15 knees) with popliteus tendinitis via an auxiliary extreme lateral approach. Clinical outcomes were assessed using the Lysholm knee scoring scale, the Tegner score, the International Knee Documentation Committee (IKDC) score and the visual analogue scale (VAS) pain score at the 24-month follow-up after surgery.

Results

A total of 15 patients (mean age, 51.1 ± 7.1 years) were included. They had a mean body mass index of 23.8 ± 2.1 kg/m². The minimum follow-up period was 24 months. Comparing the postoperative state to the preoperative state, the mean postoperative Lysholm score, Tegner score, and IKDC score improved significantly from 70.0 ± 5.0, 3.0 ± 0.9, and 62.3 ± 5.5 to 89.3 ± 4.2, 4.6 ± 0.61, and 80.5 ± 4.4, respectively (p < 0.01). The preoperative VAS score for pain improved from 6.4 ± 0.5 to 0.9 ± 0.4 (p < 0.01). No patients were lost to follow-up.

Conclusions

Following arthroscopic-assisted treatment, all the patients with popliteus tendinitis achieved satisfactory clinical outcomes in terms of pain relief and improved function.

Level of Evidence

Level IV

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 a common finding during knee arthroscopy. Usually, treatment consists of the removal of the 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 the aetiopathogenesis, the assessment tools and the therapeutic strategies for knee loose bodies 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.

Ultrasound-Assisted Posterior Knee Arthroscopy: A Description of the Technique

Entering the posterior knee with arthroscopy can be difficult. Scar tissue, a tumor, and the obese patient can make instrument placement difficult and risk iatrogenic injury. Ultrasound can be used to visualize the posterior knee and provide direct guidance of instrumentation. We describe the technique and indications for using ultrasound during arthroscopy. Accurate and atraumatic insertion of instruments can be performed with no damage to total knee components or the knee joint. Ultrasound guidance should be considered during difficult posterior knee arthroscopy.