Long-term survival and radiological results of the Duracon™ total knee arthroplasty

Purpose: The aim of this study was to analyse the long-term (>tenyears) survival rate and radiological results of the Duracon TKA. Methods: Between 1992 and 1999 159 Duracon TKA were implanted at our institution. A Kaplan-Meier survival analysis for the endpoints exchange, addition or removal of any component for any reason, revision due to aseptic loosening and mechanical failure was performed. Radiological long-term (>tenyears) follow-up (FU) analysis was performed according to the Knee Society Radiographic Evaluation and Scoring System. Results: Mean age at surgery was 74.3years, 28% were male, and 89% had primary osteoarthritis as diagnosis. Mean FU for survival analysis was 10.9years (SD 4.2). A total of 58% of the patients died during follow-up. Three patients (2.1%) were lost to follow-up and five TKA (3.1%) were revised. After tenyears the mean survival was 97.7%, 99.4% and 98.3% for the aforementioned endpoints, respectively. Mean radiological FU was 11.8years (SD 2.3). We found no significant change in alignment of the components or axis over time. Progressive radiolucencies were found in nine TKA (17%), mainly around the tibial component (95%). Conclusion: The Duracon TKA showed excellent long-term survival comparable to data from national registers and to other successful designs. Radiological changes found on plain radiographs were scarce after almost 12years of radiological follow-up indicating good implant stability

New quantitative radiographic parameters for vertical and horizontal instability in acromioclavicular joint dislocations.

PURPOSE The aim of this study was to identify the most accurate and reliable quantitative radiographic parameters for assessing vertical and horizontal instability in different Rockwood grades of acromioclavicular joint (ACJ) separations. Furthermore, the effect of projectional variation on these parameters was investigated in obtaining lateral Alexander view radiographs. METHODS A Sawbone model of a scapula with clavicle was mounted on a holding device, and acromioclavicular dislocations as per the Rockwood classification system were simulated with the addition of horizontal posterior displacement. Projectional variations for each injury type were performed by tilting/rotating the Sawbone construct in the coronal, sagittal or axial plane. Radiographic imaging in the form of an anterior-posterior Zanca view and a lateral Alexander view were taken for each injury type and each projectional variation. Five newly defined radiographic parameters for assessing horizontal and vertical displacement as well as commonly used coracoclavicular distance view were measured. Reliability, validity and the effect of projectional variation were investigated for these radiographic measurements. RESULTS All radiographic parameters showed excellent intra- and interobserver reliability. The validity was excellent for the acromial centre line to dorsal clavicle (AC-DC) in vertical displacement and for the glenoid centre line to posterior clavicle (GC-PC) in horizontal displacement, whilst the remaining measurements showed moderate validity. For AC-DC and GC-PC, convergent validity expressed strong correlation to the effective distance and discriminant validity demonstrated its ability to differentiate between various grades of ACJ dislocations. The effect of projectional variation increased with the degree of deviation and was maximal (3 mm) for AC-DC in 20° anteverted malpositioning and for GC-PC in 20° retroverted malpositioning. CONCLUSIONS AC-DC and the GC-PC are two novel quantitative radiographic parameters of vertical and horizontal instability in ACJ dislocations that demonstrate excellent reliability and validity with reasonable inertness to malpositioning. The use of AC-DC for assessing vertical displacement and GC-PC for assessing horizontal displacement in a single Alexander view is recommended to guide the appropriate management of ACJ dislocations. A better appreciation of the degree of horizontal instability, especially in lower Rockwood grades (II, III) of ACJ dislocations, may improve management of these controversial injuries

Improved identification of unstable acromioclavicular joint injuries in a clinical population using the acromial center line to dorsal clavicle radiographic measurement.

BACKGROUND Accurate classification and subsequent management of acromioclavicular (AC) joint injuries remains a contentious topic. The updated Rockwood classification acknowledges "stable IIIA" and "unstable IIIB" injuries, a watershed accepted by ISAKOS and important in guiding clinical management. Traditionally, the coracoclavicular distance is used to classify these injuries, despite well-documented limitations. This study aimed to evaluate displacement in AC joint injuries by measuring both coracoclavicular (CC) distance and the newly proposed acromial center line to dorsal clavicle (AC-DC) distance, in a cohort of patients, and correlate the results between the 2 measurements and relationship to Rockwood grade. MATERIALS AND METHODS Ninety consecutive cases of AC joint injury were evaluated radiographically for Rockwood classification, CC distance on anteroposterior radiographs, and AC-DC distance on Alexander view radiographs. Inter- and intraobserver reliability for each measurement was calculated as well as correlation between the 2 measurement types and the degree to which each measurement accurately represented the Rockwood classification. RESULTS Although both CC and AC-DC measurements showed very high inter- and intraobserver reliability, the CC distance systematically underestimated the degree of AC joint displacement when compared with the AC-DC measurement as the severity of injury increased, particularly in the presence of posterior horizontal displacement such as that seen in Rockwood IV injuries. CONCLUSION The AC-DC measurement and use of the Alexander view provides the clinician with a more realistic appreciation of true AC joint displacement, especially in defining watershed cases (ie, IIIA/IIB/IV) and may better inform the decision-making process regarding management options and recommendations

The reliability and validity of radiographic measurements for determining the three-dimensional position of the talus in varus and valgus osteoarthritic ankles

To assess the most accurate radiographic method to determine talar three-dimensional position in varus and valgus osteoarthritic ankles, we evaluated the reliability and validity of different radiographic measurements. Nine radiographic measurements were performed blindly on weight-bearing mortise, sagittal, and horizontal radiographs of 33 varus and 33 valgus feet (63 patients). Intra- and interobserver reliability was determined with the intraclass coefficient (ICC). Discriminant validity of measurements between varus and valgus feet was assessed with effect size (ES). Convergent validity (Pearson's r) was evaluated by correlating measurements to the dichotomized varus and valgus groups. Obtained measurements in both groups were finally compared with each other and with 30 control feet. Reliability was excellent (ICC > 0.80) in all but two measurements. Whereas frontal plane validity was excellent (ES and r > 0.80), horizontal and sagittal measurements showed poor to moderate validity (ES and r between 0.00 and 0.60). Four measurements were significantly different among all groups (p <0.05). Talar positional tendency was found towards dorsiflexion or endorotation in the varus group and towards plantarflexion or exorotation in the valgus group. The frontal tibiotalar surface angle, sagittal talocalcaneal inclination angle, and horizontal talometatarsal I angle showed the best reliability, validity, and difference among the groups. The frontal tibiotalar surface angle, sagittal talocalcaneal inclination angle, and horizontal talometatarsal I angle accurately determine talar three-dimensional radiographic position in weight-bearing varus and valgus osteoarthritic ankles. Careful radiographic evaluation is important, as these deformities affect talar position in all three plane

[Current aspects and new techniques in dislocation of the shoulder joint].

With 12% of all injuries concerning the shoulder, acromioclavicular (AC) joint dislocations are a common injury especially in young and active patients. The Rockwood classification is widely accepted, which differentiates between six types depending on the degree of injury and the vertical dislocation. Because the classification does not adequately address the horizontal instability, its benefits are questionable and there is currently no consensus. For this reason, the classification and the therapy of these injuries are increasingly becoming the subject of scientific investigations. Whereas conservative treatment for type I and II injuries and operative treatment for type IV-VI injuries are widely accepted, there is still no agreement in treating type III lesions. The goal of this review article is to present the current evidence for the diagnostics, different classifications and therapeutic possibilities

A biomechanical study comparing the mean load to failure of two different osteosynthesis techniques for step-cut olecranon osteotomy

Background Olecranon osteotomies are frequently used to expose distal humeral intraarticular fractures. The step-cut olecranon osteotomy (SCOOT) is an augmented version of the oblique olecranon osteotomy, which has recently been evaluated biomechanically with tension band wiring (TBW) fixation. However, complications with TBW are common. In this study, we, therefore, compared the mean load to failure of TBW with compression screws for SCOOT fixation. We hypothesized a higher load to failure for the compression screw group. Methods We performed a SCOOT on 36 Sawbones. Eighteen were fixed with TBW, and another 18 with two compression screws. The humeroulnar joint was simulated using an established test setup, which allows the application of triceps traction force through a tendon model to the ulna, while the humeroulnar joint is in a fixed position. Eight models of each fixation group were tested at 20°, and eight at 70° of flexion by isometrical loading until failure, which was defined as either a complete fracture or gap formation of more than 2 mm at the osteotomy site. Results At 20° of flexion, mean load to failure was similar between the TBW group (1360 ± 238 N) and the compression screw group (1401 ± 261 N) (P = .88). Also, at 70° of flexion, the mean load to failure was similar between the TBW group (1398 ± 215 N) and the compression screw group (1614 ± 427 N) (P = .28). Conclusions SCOOTs fixed with TBW and compression screws showed similar loads to failure. A SCOOT fixed with compression screws might be a valuable alternative for surgeons when treating intraarticular distal humeral fractures. However, future in vivo studies are necessary to confirm our results in a clinical setting

Classification and treatment of supramalleolar deformities

Supramalleolar osteotomies are increasingly popular for addressing asymmetric arthritis of the ankle joint. Still, recommendations for the indication and the use of additional procedures remain arbitrary. We preoperatively grouped different types of asymmetric arthritis into several classes and assessed the usefulness of an algorithm based on these classifications for determining the choice of supramalleolar operative procedure and the risk factors for treatment failure. Ninety-two patients (94 ankles) were followed prospectively and assessed clinically and radiographically 43 months after a supramalleolar osteotomy for asymmetric arthritis of the ankle joint. Significant improvement of the clinical scores was found. Postoperative reduction of radiological signs of arthritis was observed in mid-stage arthritis. Age and gender did not affect the outcome. Ten ankles failed to respond to the treatment and were converted to total ankle replacements or fused. Supramalleolar osteotomies can be effective for the treatment of early and midstage asymmetric arthritis of the ankle joint. However, certain subgroups have a tendency towards a worse outcome and may require additional surgery. Therefore preoperative distinction of different subgroups is helpful for determination of additional procedure

Measurement of the medial distal tibial angle.

The aim of this study was to describe the difference between the medial distal tibial angle (MDTA) when measured on whole lower limb radiographs and mortise radiographs of the ankle

Subscapularis in Reverse Total Shoulder Arthroplasty

The use of reverse total shoulder arthroplasty (RSA) is becoming increasingly popular, but many biomechanical aspects are poorly understood. Particularly, the role and function of the subscapularis following RSA are unclear. Several clinical and biomechanical studies have analyzed its role in range of motion and stability. There is some evidence that the subscapularis is beneficial for stability but may reduce range of motion. This review provides an overview of the current literature, which suggests that the subscapularis may have a more important role in RSA than originally thought