Arthroscopic Removal of a Polyethylene Glenoid Component in Total Shoulder Arthroplasty

Abstract

We present a technique for arthroscopic glenoid removal in a case of glenoid loosening after total shoulder arthroplasty (TSA). The presented technique is technically feasible and may be useful if 1-stage surgery with glenoid reimplantation is not indicated. To exclude low-grade infection, the presented technique allows for an intraoperative infection workup such as intraoperative cultures. However, glenoid loosening in TSA is a well-known problem and has been described before. The advantages of the presented technique include minimally invasive surgery, decreased pain, preservation of the subscapularis tendon, and assurance of exclusion of low-grade infection before reimplantation of a new glenoid implant. In this case a 73-year-old patient was treated with a TSA for severe osteoarthritis of the right shoulder in April 2014. Because of persistent anterior shoulder pain postoperatively, radiographic evaluation was performed and showed signs of glenoid loosening 6 months after surgery without any clinical signs of infection. To exclude low-grade infection, arthroscopy of the right shoulder was performed. Arthroscopy showed a totally loosened glenoid component leading to arthroscopic glenoid removal by use of a special forceps.

Total shoulder arthroplasty (TSA) is a common treatment option in patients with severe osteoarthritis of the glenohumeral joint to relieve pain and restore shoulder function.^1,2 Implantation of a glenoid component shows improved results in contrast to hemiarthroplasty.¹ However, glenoid loosening is a well-known problem and has been described before.^3-6 The reasons for glenoid loosening are diverse and include aseptic loosening, low-grade infection, and cuff insufficiency. To exclude low-grade infection, an uncompromising infection workup is necessary. Serum inflammatory markers are often unreliable because they have poor sensitivity in the shoulder. Therefore shoulder joint aspiration cultures, as well as intraoperative cultures, represent important diagnostic tools.⁷ Our technique allows arthroscopic removal of a loosened glenoid component with a concomitant intraoperative infection workup in terms of intraoperative cultures.

Our patient complained about anterior shoulder pain after TSA (Eclipse stemless humeral prosthesis with cemented, polyethylene keeled glenoid; Arthrex, Naples, FL) in April 2014. Radiographic evaluation showed a suspicious picture of the glenoid component with complete radiolucent lines between 1.3 and 2 mm in width (Fig 1). After arthroscopy, massive synovitis could be detected (Fig 2) and intraoperative cultures were taken. Arthroscopic glenoid removal was performed because of a completely loosened glenoid component. Later, microbiological analysis showed no bacterial growth and therefore confirmed the diagnosis of aseptic loosening of the glenoid component in TSA.

Fig 1.

(A) Anteroposterior and (B) axial radiographs of the right shoulder 6 months after stemless total shoulder arthroplasty (Eclipse stemless humeral prosthesis with cemented, polyethylene keeled glenoid). Both planes show radiographic lucent lines of 1.3 to 2 mm, indicating loosening of the glenoid component.

Fig 2.

Arthroscopic view from posterior indicating massive synovitis (a), as well as the anterior portal (b) from the posterior perspective. The humeral prosthesis is marked with an asterisk.

Surgical Technique

The patient is placed in the lateral position, and arthroscopy is performed with a 30° arthroscope (Karl Storz, Tuttlingen, Germany). Preoperatively, the anatomic landmarks are marked.

By use of a standard posterior portal, diagnostic arthroscopy is conducted, and under direct visualization, the anterior portal is established using a hollow needle. To exclude a low-grade infection, several intraoperative cultures are taken with an arthroscopic grasper (Aesculap, Tuttlingen, Germany) (Fig 3). Next, an examining hook (Karl Storz) is placed into the anterior portal to evaluate the prosthesis, as well as the glenoid component (Fig 4). With electrocautery (Erbotom ICC 350E; Erbe Elektromedizin, Tübingen, Germany) over the anterior and posterior portals, scar tissue at the level of the glenoid-bone interface is resected (360° release) (Fig 5). Under axial traction of the operated arm and by use of an arthroscopic rasp (Arthrex), the glenoid is lifted from its bony undersurface (Fig 6). If necessary, bone cement can be removed with a grasper (KingFisher; Arthrex) (Fig 7). Next, the glenoid component is further elevated with an arthroscopic rasp (30° curved arthroscopic rasp; Arthrex) until the keel of the glenoid is completely visible (Fig 8). By electrocautery, the rotator interval is extended inside out and the skin incision is lengthened to approximately 2 cm. The surgeon's finger is introduced through the extended anterior portal to check for the correct width. For extraction of the glenoid, a Bircher forceps (Bircher-Ganske Knochenhalte Zange; Zepf Medical Instruments, Tuttlingen, Germany) is passed through the anterior portal. It is important to grasp the glenoid at its cranial end and to fix it tightly between the branches of the forceps during extraction (Fig 9, Video 1). Then the glenoid can be extracted, and the anterior portal is closed in layers using subcutaneous and cutaneous sutures.

Fig 3.

Arthroscopic view displaying the arthroscopic grasper (c) taking an intraoperative culture. The humeral prosthesis is marked with an asterisk.

Fig 4.

Arthroscopic view showing the loosened polyethylene component (pound sign), bone cement, and examining hook (d) used to expose the glenoid component.

Fig 5.

Arthroscopic view showing the electrocautery device (e) used to release scar tissue at the level of the glenoid-bone interface. The glenoid component is marked with a pound sign, and the humeral prosthesis is marked with an asterisk.

Fig 6.

Arthroscopic view showing mobilization of the glenoid component. By use of a rasp (f), the glenoid (pound sign) is lifted from its bony undersurface.

Fig 7.

Arthroscopic view featuring extraction of bone cement with the arthroscopic grasper (c). The glenoid component is marked with a pound sign, and the humeral prosthesis is marked with an asterisk.

Fig 8.

Arthroscopic view displaying the mobilized polyethylene inlay exposing the keel of the glenoid component (pound signs).

Fig 9.

Postoperative photograph showing explanted polyethylene component (pound sign), bone cement (plus sign), and Bircher forceps (g).

Discussion

The described technique allows minimally invasive extraction of a loosened glenoid component after TSA. It is important to note that conventional Kocher clamps or arthroscopic graspers are not suitable for glenoid component extraction because explantation may result in glenoid loss. To avoid complications, the glenoid component has to be fixed in a very stable manner between the branches of the extracting instrument while passing the rotator interval (pearls and pitfalls are shown Table 1).

Table 1.

Pearls and Pitfalls of Presented Technique of Arthroscopic Glenoid Removal

Pearls

The anterior portal should be located within the rotator interval, and the width should average ≥2 cm.

Axial traction of the operated arm is essential to increase the intra-articular space during mobilization of the glenoid component.

A robust forceps is essential for extraction of the glenoid.

The glenoid must be fixed in a very stable manner within the branches of the extracting forceps.

Pitfalls

An insufficient anterior portal will make extraction of the glenoid impossible.

The cephalic vein should be protected; damage to the vein will lead to increased bleeding.

Kocher clamps or arthroscopic graspers are not suitable because strong fixation of the implant is not possible.

Arthroscopic glenoid removal is technically feasible and allows for a concomitant intraoperative infection workup, such as intraoperative cultures. Thereby, low grade infection can be excluded reliably, and any insufficiency of the subscapularis tendon that may result from open surgery can be avoided. Early arthroscopic removal of a loosened glenoid component may further avoid friction among cement, bone, and polyethylene, with concomitant debris and osteolysis.

In the presented case microbiologic analysis showed no bacterial growth. Thus aseptic loosening of the glenoid component was detected and confirmed by arthroscopy. The cause of glenoid loosening is multifactorial, including polyethylene wear or dissociation, such as rotator cuff tears, subscapularis insufficiency, and prosthesis instability.⁶ The diagnosis of glenoid component loosening is based on the presence of significant or progressive lucency surrounding the glenoid component with concomitant shoulder pain.⁸ Lucent lines of the glenoid component in the presence of TSA are commonly reported. However, no causal relation between radiographic lucency and clinical loosening could be detected.⁴ Clinical failure and revision TSA because of a loosened glenoid component are reported in 3% to 10% of cases that show radiographic lucent lines. Glenoid lucent lines can be classified, according to Deutsch et al.,⁹ into 6 grades. Definite glenoid loosening can be assumed when the following criteria are fulfilled:

• 1.Radiolucent lines that are 2 mm wide and complete
• 2.Progression of radiographic lucent lines on serial radiographs
• 3.Presence of cement fragmentation
• 4.Gross component migration⁹

In our patient, radiographic evaluation showed complete radiographic lucent lines between 1.3 and 2 mm in width (Fig 1), classified as grade 5 according Deutsch et al.⁹ A progression of radiographic lucent lines on serial radiographs, as well as anterior shoulder pain, was also present, so loosening of the glenoid component seemed to be likely preoperatively and could be confirmed during arthroscopy.

Bonnevialle et al.⁶ showed that revision of an anatomic TSA by reimplantation of a new glenoid implant did not inevitably solve the problem of glenoid loosening or failure. In their series of 42 patients with glenoid component loosening, 67% of the patients (28 of 42) had recurrent glenoid loosening or failure after reimplantation of a new glenoid implant.

During the preoperative differential diagnosis, diagnoses such as soft-tissue failure, prosthetic instability, low-grade infection, and bony insufficiency should be excluded before glenoid reimplantation is performed. Therefore arthroscopic glenoid removal may be a useful procedure if 2-stage surgery with secondary glenoid reimplantation is indicated.⁶

In cases of unclear glenoid loosening, we strongly recommend 2-step surgery with explantation of the loosened prosthetic component and intraoperative cultures first and reimplantation of a new prosthetic implant second. In such cases arthroscopic glenoid removal may provide considerable benefit to the patient. Thus open surgery for glenoid explantation with the potential risk of ongoing subscapularis insufficiency can be avoided.

Supplementary Data

Video 1

Arthroscopic glenoid removal after total shoulder arthroplasty in the right shoulder with the patient in the lateral position. A standard posterior portal and an enlarged anterior portal are used.