Medium-term clinical and radiographic outcomes of a cementless prosthesis with a 140° neck-shaft angle in reverse total shoulder arthroplasty.

BACKGROUND: The design of humeral implants has evolved from the initial Grammont design, notably regarding the neck-shaft angle (NSA) and through the use of cementless prostheses. Stress shielding was frequently reported with cementless implants, the 2 main risk factors being humeral stem misalignment and high filling ratios. Our hypothesis was that standard length cementless stems with an NSA of 140° would facilitate good alignment with moderate filling ratios, thereby limiting stress shielding and ensuring good clinical outcomes. METHODS: A single-center retrospective study was conducted of patients who underwent reverse total shoulder arthroplasty between January 2015 and August 2017, with at least 2 years' follow-up. Clinical evaluations included range of motion measurements and Constant and subjective shoulder values scores. Frontal alignment was assessed in terms of the angle (α) between axes of the stem and of the humerus. Filling ratios were measured in the metaphysis of the humerus, in the diaphysis, and at the distal end of the stem and considered excessive above 0.7. Stress shielding was evidenced radiographically by the observation of medial cortical narrowing, medial metaphysis thinning, lateral metaphysis thinning or under-the-baseplate osteolysis. RESULTS: Eighty-two shoulders were included and 70 had radiographic follow-up data available. The mean patient age was 78 years and 63/81 patients (78%) were female. The mean follow-up time was 39 ± 7 months. The mean α angle was 1.4° ± 0.9° and was less than 5° in all cases. The mean metaphyseal, diaphyseal, and distal filling ratios were 0.61 ± 0.06, 0.70 ± 0.08, and 0.64 ± 0.09, respectively. The mean Constant score improved from 28 ± 11 preoperatively to 64 ± 14 at last follow-up. The mean subjective shoulder values score at last follow-up was 81 ± 12. Seventy-nine percent of patients (55/70) had at least 1 form of stress-shielding related, which were not associated with clinical outcomes, apart from lateral metaphysis thinning, which was associated with lower active anterior elevation (mean, 106° ± 30° vs. 126° ± 28°; P = .01) and lower Constant scores (mean, 56 ± 17 vs. 65 ± 14; P = .06). CONCLUSION: The use of cementless reverse shoulder prostheses with a NSA of 140° was associated with good clinical outcomes at 2 years' follow-up. The prosthesis stem was correctly aligned with the humeral axis and the filling ratios were <0.7 in all cases. Stress-shielding was common but, apart from lateral metaphysis thinning, this had no impact on clinical outcomes.

Treatment and outcomes of chronic locked posterior shoulder dislocations: a retrospective case series.

BACKGROUND: Posterior shoulder dislocations are rare injuries that are often missed on initial presentation. Cases left untreated for more than three weeks are considered chronic, cannot be reduced closely (they become locked) and are usually associated with a significant reverse Hill-Sachs defect. The aim of this study was to evaluate the outcomes of chronic locked posterior shoulder dislocations treated with the McLaughlin procedure (classic or modified). METHODS: This retrospective study included 12 patients with chronic locked posterior shoulder dislocation operated on between 2000 and 2021 by two surgeons in two institutions. Patients received a thorough clinical examination and radiological assessment before and after surgery. Shoulders were repaired with the McLaughlin or modified McLaughlin procedure. Outcomes were assessed by comparing pre- and postoperative values of clinical variables. RESULTS: Most of the dislocations were of traumatic origin. The average delay between dislocation and surgical reduction was 13.5 ± 9.7 weeks. Postoperative clinical outcomes were favourable, with an average subjective shoulder value of 86.4 ± 11.1 and a normalized Constant -Murley score of 90 ± 8.3. None of the patients had a recurrence of shoulder dislocation, but one patient developed avascular necrosis of the humeral head and two patients developed glenohumeral osteoarthritis. CONCLUSIONS: In this group of patients with chronic locked posterior shoulder dislocation, the clinical outcomes of McLaughlin and modified McLaughlin procedures were satisfactory, even when surgery was significantly delayed.

Finite element analysis of the tibial component alignment in a transverse plane in total knee arthroplasty.

The research aims to analyze the tibial component rotation using the finite element method by resecting the tibia in a transverse plane at an angle between 1.5° (external rotation) and -1.5° (internal rotation). We used a three-dimensional scanner to obtain the tibia's geometrical model of a cadaveric specimen. We then exported the surfaces of the tibial geometrical model through the Computer-Aided Three-dimensional Interactive Application (CATIA), which is a Computer-Aided Design (CAD) program. The CAD program three-dimensionally shaped the tibial component, polyethylene, and cement. Our analysis determined that the maximum equivalent stress is obtained in the case of proximal tibial resection at -1.5° angle in a transverse plane (internal rotation) with a value of 12.75 MPa, which is also obtained for the polyethylene (7.693 MPa) and cement (6.6 MPa). The results have shown that detrimental effects begin to occur at -1.5°. We propose the use of this finite element method to simulate the positioning of the tibial component at different tibial resection angles to appreciate the optimal rotation.

Subcapularis tendon tear: A structure-based arthroscopic description.

INTRODUCTION: Subscapularis (SSC) tendons differ from supraspinatus tendons, although both have similar histologic structure comprising two layers with distinct collagen fiber organization. HYPOTHESIS: The partial/full-thickness tear classification for the supraspinatus based on tendon structure can be applied to the subscapularis tendon on objective criteria. MATERIAL AND METHODS: The present study used 100 films of arthroscopic rotator cuff repair involving SSC lesion. Lesions were reported on 3 objective criteria: horizontal superior tendon edge visibility, lesser tuberosity bone exposure, and lateral tendon edge visibility. Combining the three distinguishes deep, superficial or interstitial partial tear versus full-thickness tear. Degree of retraction was also noted. RESULTS: Forty-six of the 73 partial lesions involved the deep articular layer, which was often retracted, but conserving the horizontal superior tendon edge and thus misleadingly suggesting SSC integrity; 23 were interstitial, without detachment from the lesser tuberosity; 4 involved only the superficial layer. Full-thickness tears were always retracted, with loss of horizontal superior tendon edge, visibility of the lateral tendon edge and presence of comma sign. Inter- and intra-observer reproducibility was satisfactory. DISCUSSION - CONCLUSION: Like in superior cuff tear, a structure-based classification can be made of SSC lesions on objective criteria. LEVEL OF EVIDENCE: IV.

Reverse versus anatomical shoulder arthroplasty in patients with intact rotator cuff.

PURPOSE: The study objective was to compare the clinical results of reverse total shoulder arthroplasty (rTSA) and anatomical total shoulder arthroplasty (aTSA) in patients with osteoarthritis and intact rotator cuff. We hypothesised that the clinical results using rTSA would be comparable with those obtained with aTSA in this group of patients. METHODS: The study included 51 patients with shoulder osteoarthritis and intact rotator cuff who underwent rTSA or aTSA. The range of motion, Constant-Murley score and strength in external rotation were recorded pre-operatively and at the two year follow-up. Subjective post-operative results were measured using the subjective shoulder value (SSV) score and a satisfaction questionnaire. RESULTS: The post-operative improvement was significant in both groups, subjectively and concerning all parameters of the Constant-Murley score. Post-operatively, no significant difference was noted between the two groups for active anterior elevation (AAE), active external rotation (ER), internal rotation (IR) or Constant-Murley score (67 ± 12 in the rTSA group vs 71 ± 11 in the aTSA group). An exception was the Constant-Murley range of motion sub-score, which was better in the aTSA group (p = 0.028). No significant complications necessitating revision surgery were encountered. DISCUSSION: Our findings are consistent with previous studies showing good results of rTSA with shoulder osteoarthritis and intact rotator cuff with a good restoration of the IR, similar to that obtained with aTSA. CONCLUSION: The rTSA is a valid option for shoulder osteoarthritis and intact rotator cuff in older adult patients.

The Invisible MGHL Test: Diagnostic Value and Benefits for the Repair of Retracted Subscapularis Tears.

BACKGROUND: Some full-thickness subscapularis tendon tears and partial tears of the deep layer are difficult to characterize, leading to misdiagnosis. PURPOSE: To evaluate the association between displacement of the middle glenohumeral ligament (MGHL) and retracted tears of the subscapularis tendon as a possible test to improve diagnosis. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Videos (N = 100) recorded during arthroscopic rotator cuff repair involving a torn subscapularis tendon were analyzed retrospectively to assess the association between the MGHL test (nonvisibility of the MGHL) and other objective anatomic criteria. The invisible MGHL test was defined as positive if the MGHL was initially nonvisible in the beach-chair position and appeared only when the subscapularis tendon was pulled back into position by using a 30° arthroscope from the standard posterior portal. The parameters considered during the initial exploration were (1) visibility of the horizontal part of the subscapularis tendon; (2) visibility of the MGHL in its usual position, crossing the superior border of the subscapularis tendon; (3) exposure of the lateral border of the subscapularis tendon (full-thickness retracted tear); and (4) complete or partial exposure of the lesser tuberosity of the humerus. Tendon retraction was evaluated in 3 stages according to the Patte classification. RESULTS: The invisible MGHL test result was positive in 45% of cases. It was positive in 6% of cases (2 of 31) when there was no subscapularis tendon retraction and in 62% of cases (43 of 69) when there was partial or complete retraction (P < .001). The invisible MGHL test was significantly associated with the width of the tear (P < .001) and exposure of the lateral border of the subscapularis tendon (full-thickness retracted tear, P = .0002). After repair, the MGHL was visible in its anatomic position in 96% of cases. CONCLUSION: A positive invisible MGHL test is an alternative indication of subscapularis tendon retraction, and the relocation of the MGHL can also be used after repair to assess the proper anatomic repositioning of the subscapularis tendon.

The Middle Glenohumeral Ligament Test for the Diagnosis of Subscapularis Lesions.

Arthroscopy has improved the diagnosis of subscapularis tendon lesions, and the outcomes of arthroscopic repair are satisfactory. Nonetheless, the diagnosis of some partial- and full-thickness subscapularis tears remains challenging. The middle glenohumeral ligament inserts distally into the articular surface of the subscapularis tendon and can be displaced when the subscapularis tendon is torn with retraction. This article describes the middle glenohumeral ligament test, which allows retracted lesions of the subscapularis tendon to be detected even if the superior edge is visible and normally placed. In addition, it allows control of the subscapularis tendon repair.

Methods of intra- and post-operative determination of the position of the tibial component during total knee replacement.

AIM OF THE STUDY: To identify the most reliable anatomical landmarks and imaging techniques for assessing the rotation of the tibial component in total knee arthroplasty (TKA). METHODS: An extensive literature review (from January 2016 to March 2019) was performed. We included studies about primary TKA with details concerning the anatomical landmarks used for implanting the tibial component and also imaging studies assessing tibial component rotation. The final selection comprises only thirty-five articles consistent with the inclusion criteria. RESULTS: Extra-articular landmarks are not always reliable (even though the tibial tubercle is one of the most popular extra-articular landmarks used to assess the rotation of the tibial component), mainly because they vary and can lead to malrotation of the tibial component. Akagi's line (an intra-articular landmark) is considered to be the most reliable and easy to find during surgery and likewise is not affected by articular deformities. The anterior tibial cortex (intra-articular landmark) also proved to be accurate and reliable with the main advantage being that is palpable after tibial resection. Radiography provides a good and inexpensive option for imaging, but it is insufficient. Magnetic resonance imaging (MRI) is used in some cases but not routinely for assessing TKA components or their orientation. Computed tomography (CT), used together with a well-defined protocol (Berger's method being the preferred choice), remains the "gold standard" for evaluating the rotation of the tibial component after TKA. CONCLUSION: Currently, the most accurate and reliable anatomical landmarks are represented by Akagi's line and the anterior cortex of the tibia. Post-operatively, through CT and well-established protocols, the rotation of the tibial component can be accurately determined.

Relevance of Finite Element in Total Knee Arthroplasty - Literature Review.

Total knee arthroplasty (TKA) is a key surgical procedure for the treatment of severe knee osteoarthritis. Although TKA has very good clinical results, revision knee arthroplasty can sometimes be necessary due to prosthetic components malalignment which leads to early polyethylene wear, instability and aseptic loosening. Currently, the revision risk of TKA at ten years is 5%. The finite element method (FEM) is a numerical technique which allows the modelling of complex geometry and system of loads. This method is a necessity in the field of orthopedics to simulate or predict the conditions that could lead to complications or failure and react to increase the longevity of TKA. The aim of this literature review is to highlight the relevance of using FEM along with TKA. Specialty literature research shows that the use of finite element analysis is widely spread in total knee arthroplasty. It is used to compare insert materials in order to obtain the most effective method and thus decrease the wear rate. Using simulated angles, forces and stress, FEM tests different malalignment conditions in order to apply these results in the pre-operative planning and avoid a possible TKA failure. The finite element analysis has a great potential of further refining TKA alignment outcome and is very important for the analysis of knee biomechanics under different loads. FEM is used to reduce the incidence of TKA revision and to improve patients satisfaction after TKA.

Reverse total shoulder arthroplasty using helical blade to optimize glenoid fixation and bone preservation: preliminary results in thirty five patients with minimum two year follow-up.

PURPOSE: Glenoid loosening is a common cause of reverse total shoulder arthroplasty (RTSA) failure, and grafting of the glenoid is often required for revision due to bone loss due to the central peg in most glenoid baseplates. Helical blades have been used in the hip to optimize bone fixation in proximal femoral fracture. This study presents the initial results of specifically designed helical blade in the shoulder to optimize glenoid bone fixation and preservation as part of RTSA. METHODS: Thirty-five patients underwent RTSA with glenoid helical blade fixation. An uncemented glenoid baseplate was used with a central helical blade partially coated with hydroxyapatite and two or three screws. Outcome analysis was performed pre-operatively and at two years. RESULTS: All patients were satisfied with the results and significant improvement was observed in functional outcome scores between baseline and final follow-up. There was a single intra-operative undisplaced glenoid fracture which did not compromise the baseplate fixation. There was no radiographic evidence of loosening or radiolucencies around the helical blade. CONCLUSIONS: The helical blade provides a satisfactory primary fixation. Because of its length (21 mm), care should be taken in cases of pre-existing bone loss or sclerotic bone to avoid glenoid fracture or anterior cortical perforation. Helical blade has the potential to facilitate glenoid implant revision by preserving the glenoid bone stock.

Computer Assisted Total Knee Arthroplasty: Does it Make a Difference?

ABSTRACT: The longevity of total knee prostheses depends mostly on the correct alignment (frontal, sagittal and axial) of the prosthetic components, soft tissue balancing and restoring the mechanical axis of the lower limb.The use of computer-assisted navigation allows more accurate and reproducible restoration of mechanical axis and component positioning, better results in patients with extra-articular deformities and it has an important role in surgical training.Better alignment should lead to an improved functional outcome and an increased long-term survival of the prosthesis. Several studies have proven an improved function in the short and mid-term but we still lack long-term data regarding functional outcome and longevity of the prostheses.