The incidence of loosening of a cemented glenoid component in total shoulder arthroplasty, detected by means of radiolucent lines or positional shift of the component on true antero-posterior radiographs, has been reported to be between 0% to 44%. These numbers depend on the criteria used for loosening and on the length of follow-up. Radiolucent lines are however difficult to detect and to interpret, because of the mobility of the shoulder girdle and the obliquity of the glenoid, which hinder standardisation of radiographs. After review of radiolucencies around cemented glenoid components with a mean follow-up of 5. 3 years in 48 patients we found progressive changes to be present predominantly at the inferior pole of the component. This may hold a clue for the mechanism behind loosening of this implant. Since loosening is generally defined as a complete radiolucent line around the glenoid component and is difficult to assess as a result of the oblique orientation of the glenoid, an underestimation of the loosening rate using radiological data was suspected. Therefore a pilot study using Roentgen Stereophotogrammatric Analysis (RSA) was performed. In five patients an additional analysis of glenoid component loosening using digital Roentgen Stereophotogrammetric Analysis (RSA) was performed. The relative motion of the glenoid component with respect to the scapula was assessed and the length of this translation vector was used to represent migration. Loosening was defined as a migration of the component, exceeding the pessimistic estimate of the accuracy of RSA 0. 3 mm for this study. After three years of follow-up, three out of five glenoid components had loosened (1. 2 – 5. 5 mm migration). In only one patient with a gross loosened glenoid, the radiological signs were consistent with the RSA findings. It was concluded that when traditional radiographs are used for assessment of early loosening, the loosening rate is underestimated. We recommend that RSA be used for this.
To investigate the responsiveness to change of four different elbow-scoring instruments, two Hospital for Special Surgery (HSS) elbow assessment scales, the Mayo Clinic elbow-performance index (Mayo) and the Elbow Functional Assessment (EFA) scale.
A group of 24 RA patients (median age 60 years) undergoing either elbow arthroplasty (22 elbows) or synovectomy with radial head excision (3 elbows), were evaluated both prior and after surgery (median: seven months postoperatively). Score changes, obtained by using the scales under study, were calculated. The patient’s opinion of global perceived effect of the intervention was used as a criterion to classify them as ‘improved’ or ‘non-changed’. Responsiveness was evaluated with use of three approaches: using paired t-statistics (pre- and post-surgery scores), effect size statistics (standardized response mean, effect size and responsiveness ratios) and Receiver Operator Characteristic (ROC) curves.
Each of the elbow rating measures under study proved to be responsive to change when evaluating RA patients undergoing elbow arthroplasty or synovectomy. The EFA scale demonstrated the highest power to detect a clinically meaningful difference and had the best discriminative ability to distinguish improved from non-changed patients, as was revealed by all responsiveness statistics applied.
The HSS, the Mayo and the EFA elbow-scoring scales can all be used as an evaluative instrument to assess the efficacy of surgical treatment of the rheumatoid elbow joint. However, using the EFA scale will require smaller sample sizes to achieve a fixed level of statistical power than the other scales under study.
Schoulder function in the rheumatoid patient is often restricted by pain and the decrease of range of motion, muscle strength and coordination. The aim of treatment in particular joint replacement is to improve one or more of these factors to enhance shoulder function. It is unknown how much range of motion of the shoulder and the glenohumeral joint is actually needed after shoulder replacement for a reasonable function.
The shoulder function of 114 rheumatoid patients (28 male and 86 female) with a shoulder replacement was pre- and post-operatively scored at regular intervals with the Constant scale and the HSS scoring system. These scoring systems measure the ROM and daily functioning. Activities of daily living used were: dress, comb hair, wash opposite axilla and use toilet and these items were scored numerically (5=normal, 0=impossible). These items were correlated with the active ROM of the shoulder and the passive ROM of the glenohumeral joint. The passive ROM of the glenohumeral joint included the ab/adduction movement in the frontal plane, the rotation in resting position and the exorotation in 90° anteflexion. 54 Patients had a hemi-arthroplasty and 60 patients had a total shoulder prosthesis. The average follow-up was 5 years.
The average active ROM measured at follow-up was: flexion 81°±36; abduction 70°±27; exorotation 21°±23. The average passive glenohumeral motion was: exorotation in 90° flexion 42°±33; ab/adduction 51°±21; rotation 61°±30. The average functional score of the activities of daily living measured were: comb hair 2. 8±1. 9; toilet use 3. 9±1. 6 and wash opposite axilla 4±1. 5. There was a significant relationship between flexion/rotation and the functional task comb hair. The other activities of daily living were not significantly related with ROM of the shoulder. The minimal range of motion for optimal functioning of the shoulder was calculated.
Exorotation of the 90° flexed shoulder appears to be the most important parameter for an optimal functioning after shoulder prosthesis.
The value of the preoperative radiograph of the rheumatoid shoulder is underestimated for defining the moment for arthroplasty. Larsen grades 4 and 5 are widely used as radiological criterium, but this grading system is not sufficient for staging important surgical aspects as proximal migration and medialisation of the humeral head. The purpose of this study is to analyse the proximal migration and medialisation in severely destructed shoulders (Larsen 4 and 5) and to correlate this with the clinical and per-operative findings to optimize the timing for shoulder arthroplasty.
From a large group of patients with a shoulder arthroplasty those were selected who had preoperatively an involvement of the shoulder graded as Larsen 4 or 5. 104 Rheumatoid patients were selected (29 male, 75 female). The average age was 60 years (range 25–83 yrs). All patients were preoperatively clinically scored with the HSS-score, a 100 points scoring system, which assesses pain, function, power and range of motion. The radiographs were scored for the following items: gleno-humeral joint space, bone loss of glenoid, destruction of the humeral head, proximal migration and involvement of the AC-joint. The most important peroperative items were the quality of the rotator cuff and the glenoid bone mass.
69 Shoulders were graded as Larsen 4 and 35 as Larsen 5. Medialisation by bone loss of the glenoid was moderate in 65% and severe in 13. 6% of the shoulders. Proximal migration was moderate in 22% and severe in 39% of the shoulders. There was no significant correlation between medialisation and proximal migration. The rotator cuff was torn in 44% of the shoulders. Although a torn cuff was significantly related with proximal migration there were many cases with maximal proximal migration with an intact cuff. The clinical scores were not significantly related with the radiographic deterioration of the shoulder.
Because of the discrepancy between clinical findings and radiographic destruction of the rheumatoid shoulder, the radiographic findings have to play a more important role in the indication of shoulder arthroplasty to achieve a better functional and long-term result.
In rheumatoid patients the use of a long intramedullary stem in ipsilateral shoulder and elbow replacement carries the risk of humeral fracture of the small area of unviolated bone between the implants. Healing may be compromised. Because of this a short stemmed humeral head prosthesis was designed which rests on the bone surface after resection of the humeral head instead to be fixed in the shaft of the humerus. Since 1994 this prosthesis, specially designed for the rheumatoid patients has been in use in our clinic. The design rationale and the clinical results will be presented.
Since 1994 the short stemmed shoulder prosthesis has been inserted by the author in 54 shoulders. 8 Patients had osteoarthritis, 42 patients rheumatoid arthritis, 3 patients osteonecrosis and 1 patient a post-traumatic osteoarthritis. The average age was 65 years (range 32–83). In 19 shoulders a total shoulder arthroplasty was performed and the 36 shoulders a hemiarthroplasty. 32 Patients had a follow-up of more than 1 year and the average follow-up in this group is 2. 5 years (range 1-5. 5). All patients were scored clinically with the HSS score and the Constant score and radiographically before the operation, 1 year after the operation and after that at regular intervals. At follow-up pain decreased in all patients but more than 50% of the shoulders still had some mild or moderate pain during daily activities. Pre-operatively active forward flexion averaged 61°, external rotation 10° and abduction 50°. Postoperatively the active forward flexion increased to 75°, the external rotation to 19° and the abduction to 67°. The gain in ROM is similar to a group of patients operated in the same time period with another shoulder prosthesis.
The short stem shoulder prosthesis is a good alternative for a shoulder prosthesis with a long intra medullary stem. The clinical results with regards to pain reflief and gain in ROM are similar. The long term fixation of short sem humeral prosthesis remains good, without signs of radiolucency or migration. The advantage of a short stem prosthesis are:
easy technique to reconstruct the anatomical position of the humeral head bone sparing no stress shielding of the shaft no surgical problems when a long stemmed elbow prosthesis is used possibility for revision
The radiographs of sixty-four patients with seventy humeral head replacements were reviewed for signs of stress shielding. Forty-nine were implanted for rheumatoid arthritis, twenty-one for osteoarthritis. The radiographic follow-up averaged 5. 3 years. Measurements of cortex thickness were performed in four regions along the stem of the implant and the differences between the post-operative radiograph and radiograph at follow-up were calculated. The size of the stem in relation to the diameter of the humerus was calculated using validated measures, resulting in the relative stem size. A reduction of 1.6 millimeters or more was considered to be a significant reduction, because this lay outside of the calculated 95% normal range for the group as a whole. In six patients (9%) a significant reduction, in cortical thickness was observed in the proximal lateral region of the humeral stem. Five of these had rheumatoid arthritis and one osteoarthritis. In the stress shielding group the relative stem size was found to be significantly higher (p=0. 013) than in the non-stress shielding group (0. 58 versus 0. 48). Osteoporosis, especially present in rheumatoid arthritis, could well be a risk factor. It was concluded that stress shielding is a long-term complication of shoulder arthroplasty and that the relative stem size is an important factor in its genesis. These resorptive processes may lead to a higher risk of failure of the implant and gives an increased risk for mid-stem fractures, due to cantilever loading. It is also desirable to preserve the proximal bone stock, considering the difficulties that arise when, for whatever reason, revision of the implant is necessary.
The incidence of loosening of a cemented glenoid componentin total shoulder arthroplasty, detected by means of radiolucent lines or positional shift of the component on true anteroposterior radiographs, has been reported to be between 0% and 44%. Radiolucent lines are, however, difficult to detect and to interpret because of the mobility of the shoulder girdle and the obliquity of the glenoid which hinder standardisation of radiographs. We examined radiolucencies around cemented glenoid components in 48 patients, with a mean follow-up of 5.3 years, and found progressive changes to be present predominantly at the inferior pole of the component. This may hold a clue for the mechanism of loosening of this implant. In five patients we performed an additional analysis of loosening of the glenoid component using digital roentgen stereophotogrammetric analysis (RSA). After three years, three of the five implants had loosened (migration 1.2 to 5.5 mm). In only one, with gross loosening, were the radiological signs consistent with the RSA findings. When traditional radiographs are used for assessment, the rate of early loosening is underestimated. We recommend that RSA be used for this.
