Never Too Old for Arthroscopic Surgery: Woman with Low Virulence Pathogenic Shoulder Osteomyelitis - A Case Report

Summary

This study aims to demonstrate the arthroscopic management of post-operative shoulder osteomyelitis in an elderly patient, highlighting this minimally invasive approach, combined with targeted antibiotics, as an effective treatment strategy for such complex infections.

Abstract

The incidence of advanced osteomyelitis following arthroscopic shoulder surgery is rare, with few documented cases. As the need for shoulder interventions in elderly populations increases, managing these complex infections poses a significant surgical challenge. This report details the case of an 85-year-old woman who presented with fever and a fistulating portal site infection of the right shoulder. Diagnostic workup confirmed methicillin-resistant Staphylococcus aureus (MRSA). She was successfully treated with arthroscopic irrigation, debridement, and synovectomy, followed by a three-month course of oral antibiotics. At follow-up visits between three and six months, there was no clinical or laboratory evidence of recurrent infection. Osteomyelitis or septic arthritis of the shoulder, whether spontaneous or iatrogenic, is a severe complication risking joint destruction and permanent dysfunction. This case demonstrates that arthroscopic decompression combined with targeted systemic antibiotic therapy is an effective management strategy. Repeat lavage should be considered if symptoms persist, offering a viable approach to achieve infection control and preserve shoulder function in elderly patients.

Introduction

This is the first documented case of post-operative shoulder osteomyelitis caused by a low-virulence pathogen in an elderly patient, demonstrating the value of arthroscopic technique for this condition. Despite centenarians (individuals aged over 100) being ordinary, this population is still growing headlong. It is estimated that the proportion of the elderly in various regions will reach 28% in 2050, while the elderly population in China already accounts for 12.5%, and the number of people over the age of 80 has reached 19 million¹. In the wake of the number of centenarians expected to increase significantly in the next few years, the need for shoulder-related surgery in this population represents a major challenge for clinical surgeons².

Despite an increasing trend in the number of shoulder surgeries, shoulder infection is a rare and serious post-operative complication, with an incidence of about 1%³. Arthroscopic repairing surgeries of shoulder joint injuries, including proximal humerus fracture, rotator cuff tear, and superior labrum anterior and posterior (SLAP) injury, have become a more commonly used surgical approach compared with incision for shoulder joint surgery^4,5. In the aspect of wound infection, studies have shown that the deep infection rate after arthroscopic surgery is 0.44%, which is significantly lower than the deep infection rate of 2.45% after open surgery⁶. Although arthroscopic surgery can reduce the deep joint infection rate in shoulder joint trauma and tendonopathy, it is suggested that deep joint infection may still occur after arthroscopic surgery^7,8. The most common causative organisms of infection after arthroscopy or shoulder arthroplasty are Cutibacterium acnes(approximately 39%) and Coagulase-negative Staphylococcus (approximately 29%)^9,10. The inflammatory reaction of shoulder joint infection caused by pathogenic microorganisms with low toxicity, such as Cutibacterium acnes, is milder, but according to the traditional detection indicators, such as white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), C- reactive protein (CRP) and joint fluid aspiration has lower sensitivity^11,12.

Literature reported that the shoulder joint infections caused by Staphylococcus aureus and other highly virulent pathogenic microorganisms are often easy to diagnose and are usually treated with revision surgery, with a secondary arthroscopic revision surgery^13,14. However, shoulder joint infections caused by Cutibacterium acnes and Coagulase-negative Staphylococcus can be effectively eliminated by either primary or secondary surgical revision, and the selection of the optimal treatment is still controversial^15,16. The clinical manifestations of early and subacute shoulder joint infections become increasingly obvious, whereas the late stage often lacks specific manifestations, making the diagnosis of shoulder infection more difficult. The diagnosis and treatment of shoulder joint infection remain challenging¹⁷.

Simple proximal humerus fracture is relatively rare, and non-operative treatment is feasible for proximal humerus fracture shift ≤1 cm¹⁸. However, the current studies have shown that for patients with proximal humerus fracture combined with rotator cuff injury or shoulder dislocation, non-operative treatment usually needs a long rehabilitation period and poor functional recovery^19,20. Compared with traditional incision surgery, arthroscopic surgery not only combines diagnosis and treatment at the same time, but also has clear vision during the operation, and has been increasingly applied for the treatment of proximal humerus fractures. Arthroscopic surgery has the following advantages: (1) Comprehensive evaluation of shoulder joint injuries can be performed in the same period for the treatment of combined injuries, so as to avoid missed diagnosis and treatment as much as possible and to avoid more serious shoulder instability during the long run; (2) The visual field under the arthroscopy is clearer and more comprehensive, the fracture morphology can be grasped accurately; (3) It has significant advantages for the fixation of comminuted and avulsion fractures; indeed, due to the long learning curve and great technical difficulty of arthroscopy, with the prolongation of the operation time, the potential risk of surgery will be correspondingly increased^21,22. Consequently, the performer's experience and technical requirements are higher, which should also be paid attention to clinically.

Post-operative shoulder infection is still a major concern to be solved. It is still unclear whether it is necessary to use prophylactic antibiotics^17,23. However, intra-articular shoulder infection is difficult to treat due to the limited diffusion of antibiotics and the existence of drug-resistant bacteria, and it can easily lead to joint function loss after infection^24,25,26. Hence, a thorough investigation, review, and summary of existing literature will help to develop a systematic treatment plan for future management practice.

Herein, a case of an 85-year-old woman with low virulence pathogenic shoulder osteomyelitis is reported. The osteomyelitis was caused by Methicillin-resistant Staphylococcus aureus and showed typical signs of infection. Ultimately, an arthroscopic procedure was performed to debride the infectious lesion, highlighting the dominant positions for microtraumatic treatment of such lesions. This is also the first encounter for us with a case of elderly post-operative shoulder osteomyelitis with low virulence, representing a worthwhile application of the arthroscopic technique for the shoulder joint.

CASE PRESENTATION:

Diagnosis, assessment, and plan:
Chief complaints
An 85-year-old woman was referred to the outpatient department with symptoms of subcutaneous suppuration, recurrent pain, and limited movement of the right shoulder for 3 weeks.

History of present illness
The patient reported the symptom of pain and mass to have first appeared 3 weeks previously, and an ulceration occurred within 1 week (with treatment of wound dressing change, taking conventional anti-infective drug). The patient also described the pain as well as involving the anteromedial area of the right shoulder, in the wake of loss of motion of the shoulder joint. Additionally, the patient did not have fever, weight loss, or perspiration during sleep.

History of past illness
The patient had a history of hypertension, taking irbesartan and hydrochlorothiazide orally for several years. The patient underwent superior labrum anterior and posterior repairing surgery and internal fixation surgery of the right proximal humerus fracture in 2008. She underwent open reduction and internal fixation of the left proximal humeral fracture in 2020 (Figure 1).

Personal and family history
The patient had an unremarkable personal and familial medical history, including psycho-social history.

Physical examination
The basic information of the patient was as follows: 152 cm height, 32 kg weight, body temperature 36.1 °C, pulse 60/min, respiration 20/min, blood pressure 165/60 mmHg, BMI: 15.07. Diffuse swelling and ulceration were found on the anterolateral side of the right shoulder (1.5 cm × 1.5 cm). Purulent secretion was seen flowing out, with the area around the wound slightly red and swollen. No obvious tenderness, no abnormality in sensation or blood flow (Figure 2). Visible flexion was noted, with active flexion to 60°, and passive flexion to 10°. Pre-operative physical examination: Hug up (+), Bear up (+), Hug off (+), belly press (+), Napoleon sign (+), Jobe test (+), Whipple test (+), Speed test (-), bicep load (-), Neer sign (+), modified Neer sign (+).

Laboratory examinations
The main abnormal peri-operative laboratory tests are shown in Table 1, Table 2, and Table 3.

Initial diagnosis
Combined with medical history, clinical symptoms, physical and imaging examinations, and laboratory test results, a preliminary diagnosis was concluded: (1) Osteomyelitis of the right shoulder joint: low-toxic bacterial infection; (2) Internal fixation of the right shoulder greater tuberosity fracture; (3) Post-operative left proximal humerus fracture.

Protocol

This study was approved by the Human Ethics Committee of The First Affiliated Hospital, School of Medicine, Zhejiang University. The reagents and the equipment used are listed in the Table of Materials.

1. Pre-operative assessment and preparation

1. Diagnostic confirmation: The diagnosis of osteomyelitis was confirmed via the steps below:
   1. Pre-operative MRI findings consistent with joint abscess, bony destruction, and intraosseous signal changes (Figure 3).
   2. Diagnostic arthrocentesis yielded purulent fluid with a synovial fluid glucose level of 1.4 mmol/L.
2. Patient positioning: The anesthetized patient was positioned in an oblique lateral decubitus position.
3. Vital signs monitoring: Blood pressure was maintained at approximately 100/70 mmHg.
4. Surgical site preparation
   1. Anatomical landmarks were marked, including the acromion, coracoid process, and acromioclavicular joint (Figure 4).
   2. A standard surgical scrub and draping of the right shoulder were performed.
   3. Sequential wound soaking with 3% hydrogen peroxide followed by 10% povidone-iodine solution was applied.
   4. A sterile, waterproof surgical adhesive membrane was applied.

2. Arthroscopic debridement and irrigation

NOTE: Figure 5 shows the intraoperative arthroscopic findings and debridement steps.

1. Portal establishment
   1. A standard posterior viewing portal was established using a #11 blade for the skin incision.
   2. A 4.0 mm 30-degree arthroscope was inserted into the glenohumeral joint and then into the subacromial space.
   3. An anterosuperior and an anteroinferior working portal were established under direct arthroscopic visualization using an outside-in technique with an 18-G spinal needle.
2. Diagnostic arthroscopy and initial debridement
   1. The glenohumeral joint and subacromial space were systematically inspected.
   2. Proliferative scar tissue was debrided from the subacromial bursa using a 4.5 mm full-radius resector.
   3. The sinus tract connecting the infected lesion to the proximal humerus was identified.
3. Intraosseous debridement and screw removal
   1. The sinus tract was excised entirely and sent for histopathological analysis.
   2. The bony defect (approximately 6 mm in diameter) located 1 cm distal to the midpoint of the greater tuberosity was identified.
   3. The humeral head and shaft were probed to assess the extent of intraosseous involvement.
   4. All visualized pseudomembranous and necrotic tissue was debrided from the medullary cavity.
   5. Using a 5.0 mm drill, two cortical access windows were created into the humeral medullary canal:
      1. The first window was created 6 cm distal to the greater tubercle along the humeral long axis.
      2. The second window was created 8 cm distal to the greater tubercle along the humeral long axis.
   6. Through these access windows, curved curettes and motorized shavers were used to debride the intramedullary canal.
   7. The loose metallic screw was identified and removed under direct visualization.
4. High-volume pulsed lavage
   1. The irrigation was performed using 9–12 L of normal saline (0.9% NaCl) solution.
   2. A pulsed lavage system set at a pressure of 10–12 psi was utilized for delivery.
   3. The irrigation was continued until the effluent was clear of all visible debris.

3. Wound closure and post-operative immobilization

1. Drain placement: A 3.2 mm closed suction drain (e.g., Jackson-Pratt drain) was inserted into the subacromial space via a separate stab incision.
2. Closure: All arthroscopic portal incisions were closed in a layered fashion using 3-0 Vicryl for subcutaneous tissue and 4-0 Monocryl for skin.
3. Immobilization: A standard shoulder immobilizer was applied with the shoulder in a neutral position.
4. Post-operative transfer: The recovered patient was transferred to the ward for monitoring.

Results

Post-operative findings
Pseudomembranous tissue was observed on the head and shaft of the humerus during the operation, and there was evidence of shoulder joint infection with an intra-humerus lesion. In combination with the patient's etiology results, sensitive antibiotics were used for anti-infection treatment, including vancomycin and synthetic antibiotics. Vancomycin (1000 mg, Q12h) and moxifloxacin (300 mg, QD-IVGT) were used for 3 days after surgery. Then vancomycin (500 mg, Q12h) and rifampici...

Discussion

Septic arthritis and osteomyelitis of the shoulder are rare but devastating complications following arthroscopic surgery, with reported incidences below 1%. Table 4 provides a literature review of documented or presumed cases of shoulder infection or osteomyelitis. The past reports of open proximal humerus fractures date back to 1907 by Keen²⁷. Open reduction and internal fixation of proximal humerus fracture remained the standard surgical treatment up to now, whe...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Arthroscopic equipment	Smith&Nephew Company, US	REF3894	A device that uses a small camera and light source to visualize the internal structures of a joint. It is typically used alongside a series of some instruments and tools to perform surgery or examinations.
Clinical bacterial culture identification reagent	BioMérieux Company, France	CN2050025	micrococcus identification kit
MRI equipment	GE Company, US	SIGNA Voyager 3.0T	By applying an external gradient magnetic field to detect the emitted electromagnetic waves, the positions and types of atomic nuclei within an object can be determined, based on which an internal structural image of the object can be created.
Vancocin (medicine)	Edding Group Company	H20140174	500mg/bottle
X ray equipment	GE Company, US	Discovery XR656 Plus	A commonly used medical imaging technique that generates images of internal structures of the body, particularly bones and certain organs, by using low doses of radiation.