Summary

The effect of polyethylene wear and lift-off between the tibial and femoral components on the mechanical axis was assessed in primary TKA (Total Knee Arthroplasty) based on retrieval data and full leg radiographs.

Increased modularity of total hip arthroplasty components has occurred, with theoretical advantages and disadvantages. Recent literature indicates the potential for elevated revision rates of modular neck systems and the potential for metallosis and ALVAL (Aseptic Lymphocyte dominated Vasculitis Associated Lesion) formation at the modular neck/stem site. Retrieval analysis of one modular neck implant design including SEM (Scanning Electron Microscopy) assessment was done and correlated to FEA (Finite Element Analysis) as well as clinical features of patient demographics, implant and laboratory analysis. Correlation of the consistent corrosion locations to FEA indicates that the material and design features of this system may result in a biomechanical reason for failure. The stem aspect of the modular neck/stem junction may be at particular risk.

Introduction

Coronal plane alignment is one of the contributing factors to polyethylene wear in total knee arthroplasty (TKA). The goal of this study was to evaluate the wear and damage patterns of retrieved tibial polyethylene inserts in relationship to the overall mechanical alignment and to the position of the tibial component.

We sought to determine what dimensional changes occurred from wear testing of a total knee implant, as well as whether any changes developed within the polyethylene subsurface. Three fixed bearing implants underwent wear simulator testing to 6.1 million cycles. Gravimetric analysis and micro-CT scans were performed pre-test, mid-test, and post-test. Wear volume and surface deviations were greater during 0–3.2 million cycles (91±12 mm³) than from 3.2–6.1 million cycles (52±18 mm³). Deviations (wear and creep) occurred across all surfaces of the tibial inserts, including the articular surface, backside surface, sides, and locking mechanism. No subsurface changes were found. The micro-CT results were a useful adjunct to gravimetric analysis, better defining the dimensional changes that occurred with testing and ruling out subsurface fatigue.

Study design: Retrospective study of 34 patients with a massive rotator cuff tear, who were treated with an arthroscopic tuberoplasty, debridement of the degenerate cuff and biceps tenotomy.

Objectives: To evaluate the clinical outcome of a reversed decompression at the medium term follow up.

Summary of background data: Rotator cuff repair can become impossible for massive tears in the elderly. If conservative management fails, a reverse total shoulder arthroplasty (RSA) is commonly used. However, Fenlin described in 2002 a tuberoplasty for this pathology and reported good to excellent results. This procedure appears to be well tolerated as it is arthroscopic, not time consuming and not depending on intensive physiotherapy. In case of failure, a primary RSA is still possible.

Methods: 36 patients treated with a tuberoplasty between February 2002 and September 2006 were identified.

One patient deceased, one patient developed Alzheimer dementia, leaving 34 patients available for follow-up. They completed the SF-36 questionnaire and the Simple shoulder test. They were clinically reviewed and scored with the Constant-Murley score. All 34 had complete radiographic work-up (x-ray; ultrasound) preoperatively and at final follow up.

Results: Median age at operation was 71 years (range: 52,5 – 82,16). Mean follow-up was 3,1 years (SD: +/− 0,75).

Mean operating time was 35 minutes (SD: +/− 12.33). There were no surgical complications. Postoperatively, there was an uneventful recovery in all patients.

At final follow-up, two patients were revised to a RSA. One patient was revised after 9 months because of continuous pain and loss of function. The second patient developed a complete osteonecrosis and was revised after one year.

The 32 remaining patients had a preoperative Constant-Murley score adjusted for age and gender of 34,8. This improved to an average of 84 at final follow up.

The simple shoulder test improved from an average of 1,8 to 8,4.

The average decrease of subacromial space was 2,34 mm and the loss of glenohumeral joint space was 0,57. Finally, the preoperative grade of arthrosis was 0,46 compared to a postoperative average of 1,1.

At final follow-up, 85% (27/32) were either satisfied or very satisfied with the result. 12,5% (4/32) appreciated the result as only fair. 2,5% (1/32) was dissatisfied, but didn’t consider revision surgery.

Conclusion: We conclude that a tuberoplasty with rotator cuff debridement and biceps tenotomy is a reliable treatment for massive rotator cuff tears in the elderly at medium follow up. In case of failure, revision to RSA is still a valuable option.

We report a long term experience on massive rotator cuff tears treated by the means of a nonresorbable transosseously fixed patch combined with a subacromial decompression

From December 1996 until August 2002, a total of 41 patients were treated with a synthetic interposition graft and subacromial decompression. All patients had a preoperative ultrasound evidence of a primary massive full-thickness tear that was thought to be irreparable by simple suture. All patients were evaluated pre- and postoperatively using the Constant and Murley score, DASH questionnaire, Simple Shoulder Test, VAS scale for pain, ultrasound and plain radiographs.

The patients consisted of 23 men and 18 women aged 51–80 years (mean 67 years). We had a lost of follow up of 6 patients. One patient had a total shoulder arthroplasty at 7.7 years and one patient had a redo with a new synthetic graft at 9.6 years. They were followed up for a mean of 7.2 years. Their mean preoperative Constant and Murley score improved from 25.7 preoperatively to 69.6. Similar improvements were seen with the DASH score (56.6 to 23.3), SST (1.2 to 7.9) and VAS scale (75.4 to 14.1)

Anatomically, the repair resulted in mean acromio-humeral interval of 6.6 mm. Ultrasound showed a further degeneration of the rotator cuff with tears posteriorly from the interposition graft. In 67.7% of all patients the graft was continuous present. Histology – obtained from one patient scheduled for a reversed shoulder arthroplasty- showed partial ingrowth of peri-tendinous tissue.

Despite ongoing degeneration of the cuff in nearly half our population, restoring a massive rotator cuff defect with a synthetic interposition graft and subacromial decompression can give significant and lasting pain relief with a significant improvement of ADL, range of motion and strength.

Role of ultrasonography in shoulder pathology: Consistency with clinical and operative findings K. W. Chan, G. G. McLeod Department of Trauma and Orthopaedic Surgery, Perth Royal Infirmary, Perth PH1 1NX, United Kingdom.

Shoulder disorders are common and main causes of shoulder pain with/without functional deficit include adhesive capsulitis (frozen shoulder), impingement syndrome and rotator cuff pathology. The sensitivity and specificity of ultrasonography have been reported as 80% and 100% respectively in the literature. We carried out a retrospective case note review of patients that underwent ultrasonography of shoulder, comparing the radiological findings with clinical diagnosis and operative findings. 58 patients, 36 male and 22 female attended the orthopaedic outpatient clinic with painful shoulder and underwent ultrasonography of shoulder during the period of study. Mean age of patients is 55 (range 28 to 78 years old). 33 patients had ultrasonography of right shoulder, 20 patients had ultrasonography of left shoulder while 5 patients had ultrasonography of both shoulders. 79% (50/63) of the ultrasonography findings were consistent with clinical diagnosis. 17 patients had normal findings on ultrasonography and were discharged fully. 25 patients with clinical and radiological diagnosis of biceps tendon tear, calcifying tendinosis and partial/full thickness rotator cuff tear were treated conservatively. 19% (4/21) of patients with diagnosis of calcifying tendinosis had decompression surgery. 38% (8/21) of patients with diagnosis of partial/full thickness rotator cuff tear had decompression surgery + rotator cuff repair. The degree of rotator cuff tear in operative findings for 6 out of 8 patients (75%) that underwent decompression surgery +/− rotator cuff repair were consistent with ultrasonography findings. 4 patients had inconclusive ultrasonography findings and had magnetic resonance imaging to further confirm the pathology. We conclude that ultrasonography should be used as the first line of investigation in aiding the clinical diagnosis and management of shoulder disorders as it is non-invasive and cost effective. The sensitivity of ultrasonography in detecting shoulder pathology is 75% from this study.