Pyrocarbon hemiprostheses show little glenoid erosion and good clinical function at 5.5 years of follow-up.

BACKGROUND: The success of traditional shoulder hemiarthroplasty (HA) with cobalt-chromium heads is limited by painful glenoid erosion with problematic bone loss. Hemiprostheses with pyrolytic carbon (PyC) heads have shown reduced glenoid erosion in experimental laboratory studies. Few in vivo data are available. METHODS: We performed a single-center consecutive cohort study of 31 of 34 patients (91%) who underwent PyC HA between September 2013 and June 2018. In 11 of these patients, concentric glenoid reaming was additionally performed. The mean follow-up period was 5.5 years (range, 3.5-7 years). Standardized radiographs were taken, and clinical function (Constant score) and pain (visual analog scale score) were recorded. Anteroposterior radiographs were analyzed according to an established method by 2 independent observers: A line parallel to the superior and inferior glenoid rim was translated to the most medial point of the glenoid surface. A further parallel line was placed on the spinoglenoid notch. The distance between these 2 lines was measured. Measurements were scaled using the known diameter of the implanted humeral head component. To assess eccentric erosion, anteroposterior and axial images were classified according to Favard and Walch, respectively. RESULTS: Mean medial glenoid erosion measured 1.4 mm at an average of 5.5 years of follow-up. In the first year, 0.8 mm of erosion was observed, significantly more than the average erosion per year of 0.3 mm (P < .001). Mean erosion per year was 0.4 mm in patients with glenoid reaming vs. 0.2 mm in those without reaming (P = .09). An evolution of glenoid morphology was observed in 6 patients, of whom 4 had a progression of the erosion grade. The prosthesis survival rate was 100%. The Constant score improved from 45.0 preoperatively to 78.0 at 2-3 years postoperatively and 78.8 at latest follow-up (5.5 years postoperatively) (P < .001). The pain score on a visual analog scale decreased from 6.7 (range, 3-9) preoperatively to 2.2 (range, 0-8) at latest follow-up (P < .001). There was a weak correlation (r = 0.37) between erosion and pain improvement (P = .039) and no correlation between erosion and change in Constant score (r = 0.06). CONCLUSION: PyC HA caused little glenoid erosion and a sustained improvement in clinical function in our cohort at mid-term follow-up. PyC demonstrates a biphasic development of glenoid erosion, with a reduced rate after the first year. PyC HA should therefore be considered as an alternative to cobalt-chromium HA and to anatomical total shoulder arthroplasty for patients with a high risk of glenoid component complications.

Dislocation Arthropathy of the Shoulder.

Glenohumeral osteoarthrosis (OA) may develop after primary, recurrent shoulder dislocation or instability surgery. The incidence is reported from 12 to 62%, depending on different risk factors. The risk of severe OA of the shoulder following dislocation is 10 to 20 times greater than the average population. Risk factors include the patient's age at the first episode of instability or instability surgery, bony lesions, and rotator cuff tears. For mild stages of OA, arthroscopic removal of intraarticular material, arthroscopic debridement, or arthroscopic arthrolysis of an internal rotation contracture might be sufficient. For severe stages, mobilization of the internal rotation contracture and arthroplasty is indicated. With an intact rotator cuff and without a bone graft, results for anatomical shoulder arthroplasty are comparable to those following primary OA. With a bone graft at the glenoidal side, the risk for implant loosening is ten times greater. For the functional outcome, the quality of the rotator cuff is more predictive than the type of the previous surgery or the preoperative external rotation contracture. Reverse shoulder arthroplasty could be justified due to the higher rate of complications and revisions of non-constrained anatomic shoulder arthroplasties reported. Satisfactory clinical and radiological results have been published with mid to long term data now available.

RSA, TSA and PyC hemi-prostheses: comparing indications and clinical outcomes using a second-generation modular short-stem shoulder prosthesis.

INTRODUCTION: The goal of this study was to provide an insight into the clinical results after modular short-stem shoulder arthroplasty for various indications. MATERIALS AND METHODS: A consecutive cohort study of 76 patients followed up for 23-55 (mean 31.4) months. 23 anatomical (TSA), 32 reverse (RSA) and 21 hemi-prostheses with a pyrocarbon head (PyC), using a modular short stem with proximal porous coating were implanted. Range of motion, pain and Constant score (CS) were recorded. Comparisons of pre- vs postoperative outcomes, between prosthesis types and indications, were made. RESULTS: All prosthesis types brought about a significant improvement (p < 0.05) in all measured outcomes. TSA had a significantly higher increase in the CS than PyC and RSA (p = 0.002 and 0.003, respectively). TSA produced superior gains in all ROM compared with RSA (p < 0.02). RSA brought about significantly smaller improvements in internal rotation than TSA and PyC (p = 0.0001 and 0.008, respectively). TSA had greater pain relief than PyC (p = 0.02). TSA with Walch A glenoids seemed to improve more than type B in the CS. PyC patients with Walch B glenoids improved more than Walch A (p = 0.03). When implanted due to Osteoarthritis (OA), PyC had a comparable final outcome to TSA (p = 0.95), although the preoperatively worse TSA patients had a greater improvement in the CS (p = 0.026). The outcome of RSA did not differ between indications, but Walch A glenoids tended to improve more. CONCLUSIONS: Using a second-generation short-stem shoulder prostheses, TSA achieves the best clinical improvements overall, especially for OA with a Walch A glenoid. Despite refixation of the subscapularis tendon in all cases, RSA has inferior internal rotation than TSA and PyC, suggesting a mechanical limitation. OA, a Walch B glenoid and arthritis caused by instability seem to be ideal indications when considering PyC.

Cementless curved short stem shoulder prostheses with a proximal porous coating: ingrowth properties at 2-5 years of radiological follow-up with clinical correlation.

BACKGROUND: Little is known about the way the newest generation of stems integrate into the proximal humerus and their effect on the surrounding bone. Factors that may influence ingrowth have not been investigated. METHODS: A consecutive cohort study was conducted that examined 74 anatomical, reverse, or pyrocarbon hemiprostheses, using a curved modular short stem with a proximal porous coating 2-5 years postoperatively (mean 35 months). X-rays were reviewed by 2 examiners independently. Bone loss was scored with 1 point per zone with partial and 2 points per zone with complete resorption (10 zones). The Constant score was used for clinical correlation. Multiple linear regression was employed to investigate correlations between variables. RESULTS: No subsidence or shift of the stems occurred. Two of 74 patients showed 1 zone of periprosthetic lucency of 1 mm. The filling ratio averaged 0.54 (range: 0.36-0.75). Thirty patients (40.5%) displayed bone resorption, first seen at 16.6 months (range: 3-40 months), commonly in zones 1 and 5. A total of 22 patients had ≥1 zone with partial resorption, and 8 (10.8%) developed full thickness resorption after 32 (range: 10-49) months.One new finding was that female sex and older age accounted for 51% of the variation of the filling ratio. A high filling ratio, especially when >0.55, correlated with bone resorption (P < .001). Age, sex, and prosthesis type did not directly predict bone resorption. Bony sclerosis correlated with a high filling ratio (P = .019) and thereby indirectly with resorption. A direct correlation between sclerosis and resorption was narrowly insignificant (P = .058) once correcting for the filling ratio. Reverse shoulder prosthesis had a higher filling ratio than total shoulder prosthesis patients (P < .001), resulting indirectly in more bone resorption. The preoperative diagnosis did not significantly correlate with the filling ratio (P = .59) or the resorption score (P = .69). A varus or valgus alignment did not predict resorption (P = .21) or the formation of sclerotic lines (P = .93). Bone loss did not correlate with clinical results. CONCLUSIONS: These short stems are firmly anchored 2-5 years postoperatively. However, significant bone loss, linked to a high filling ratio (>0.55), is observed proximally around these stems. The development of sclerotic lines around the stem indicates oversizing. Other factors were not found to have a significant effect on stem ingrowth. The implantation of stems with a large filling ratio is more common in older females and in patients receiving reverse shoulder prosthesis. Autologous impaction bone grafting could downsize the required stem. If adequate hold is not afforded by a suitably small stem, cementation is advisable.

Impingement Syndrome of the Shoulder.

BACKGROUND: Shoulder pain is the third most common musculoskeletal complaint in orthopedic practice. It is usually due to a defect of the rotator cuff and/or an impingement syndrome. METHODS: This review is based on pertinent literature retrieved by a selective search of the Medline database. RESULTS: Patients with shoulder impingement syndrome suffer from painful entrapment of soft tissue whenever they elevate the arm. The pathological mechanism is a structural narrowing in the subacromial space. A multiplicity of potential etiologies makes the diagnosis more difficult; it is established by the history and physical examination and can be confirmed with x-ray, ultra - sonography, and magnetic resonance imaging. The initial treatment is conservative, e.g., with nonsteroidal antiinflammatory drugs, infiltrations, and patient exercises. Conservative treatment yields satisfactory results within 2 years in 60% of cases. If symptoms persist, decompressive surgery is performed as long as the continuity of the rotator cuff is preserved and there is a pathological abnormality of the bursa. The correct etiologic diagnosis and choice of treatment are essential for a good outcome. The formal evidence level regarding the best treatment strategy is low, and it has not yet been determined whether surgical or conservative treatment is better. CONCLUSION: Randomized controlled therapeutic trials are needed so that a standardized treatment regimen can be established.