Humeral head size predicts baseplate lateralization in reverse shoulder arthroplasty: a comparative computer model study.

Background: In reverse shoulder arthroplasty (RSA), the ideal combination of baseplate lateralization (BL), glenosphere size (GS), and glenosphere overhang (GOH) with a commonly used 145° neck shaft angle (NSA) is unclear. This is the first study evaluating correlations of body height (BH), humeral head size (HS), glenoid height (GH), and association of gender with best glenoid configurations for range of motion (ROM) maintaining anatomic lateralization (aLAT) for optimized muscle length in 145° and less distalized 135° RSA. Methods: In this computer model study, 22 computed tomographies without joint narrowing were analyzed (11 male/female). A standardized semi-inlay 145° platform stem was combined with 20 glenoid configurations (baseplate [B] 25, 25 + 3/+6 lateralized [l], 29, 29 + 3/6l combined with glenosphere 36, 36 + 2 eccentric [e], 36 + 3l, 39, 39 + 3e, 39 + 3l , 42, 42 + 4e). Abduction-adduction, flexion-extension, external rotation-internal rotation, total ROM (TROM), and total notching relevant (TNR) ROM were computed, best TROM models respecting aLAT (-1 mm to +1 mm) and HS/GH recorded. Second, the 145° models (Ascend Flex stem; Stryker, Kalamazoo, MI, USA) were converted and compared to a 135° inlay RSA (New Perform stem; Stryker, Kalamazoo, MI, USA) maintaining GOH (6.5-7 mm) and aLAT. Results: Best 145° models had eccentric glenospheres (mean BL: 3.5 mm, GOH 8.8 mm, GS 38.1 mm, distalization 23 mm). The 135° models had concentric glenospheres, mean BL 3.8 mm, GOH 6.9 mm, GS 39.7 mm, and distalization 14.1 mm. HS showed the strongest positive correlation with BL in 145° and 135° models (0.65/0.79). Despite reduced GOH in smaller females with a 135° NSA, adduction, external rotation, extension, TNR ROM, and TROM were significantly increased (P = .02, P = .005, P = .005, P = .004, P = .003), abduction however reduced (P = .02). The same trends were seen for males. Conclusion: HS is a practical measure in surgery or preoperatively, and the strong positive correlation with BL is a useful planning aid. Despite reduction of GOH, conversion to a less distalized 135° NSAinlay design is powerful to maintain and even significantly increase all components of TNR ROM (extension/external rotation/adduction) in small females with the drawback of reduced abduction which may however be compensated by scapula motion. Lateralization with a less distalized 135° RSA optimizes muscle length, may facilitate subscapularis repair, and maintains highest rigid body motion.

Bone Cuts Accuracy of a System for Total Knee Arthroplasty including an Active Robotic Arm.

INTRODUCTION: This study aimed to assess the bone cuts accuracy of a system for total knee arthroplasty including an active robotic arm. A second objective was to compare the accuracy among orthopaedic surgeons of different levels of experience. METHODS: Three orthopaedic surgeons cut 10 sawbone knees each. Planned and actual bone cuts were compared using computed tomography. Difference with respect to the planning was expressed as three position and three orientation errors following the anatomical planes. Statistical tests were performed to detect bias and compare surgeons. RESULTS: None of the 30 knees presented an outlier error, meaning an error ≥3 mm or ≥3°. The root-mean-square values of the 12 error types were below 0.8 mm or 0.8°, except for the femoral proximal-distal errors (1.7 mm) and the tibial anterior-posterior errors (1.4 mm). Biases were observed, particularly in femoral proximal-distal and tibial anterior-posterior positions. Median differences between surgeons were all lower than 0.8 mm and 0.5°, with statistically significant differences among surgeons in the femoral proximal-distal errors and the tibial anterior-posterior errors. CONCLUSIONS: The system tested in this study achieved accurate bone cuts independently of the surgeon's level of experience. Biases were observed, suggesting that there might be options to improve the accuracy, particularly in proximal-distal position for the femur and in anterior-posterior position for the tibia.

Total knee arthroplasty improves the quality-adjusted life years in patients who exceeded their estimated life expectancy.

PURPOSE: Total knee arthroplasty (TKA) is the treatment of choice for end-stage osteoarthritis though its risk-benefit ratio in elderly patients remains debated. This study aimed to evaluate the functional outcome, rates of complication and mortality, and quality-adjusted life years (QALY) in patients who exceeded their estimated life expectancy. METHODS: Ninety-seven TKA implanted in 86 patients who exceeded their estimated life expectancy at the time of TKA were prospectively included in our institutional joint registry and retrospectively analyzed. At latest follow-up, the functional outcome with the Knee Society Score (KSS), rates of complication and mortality, and QALY with utility value of EuroQol-5D score were evaluated. RESULTS: At a mean follow-up of three ± one years, the pre- to post-operative KSS improved significantly (p < 0.01). The rates of surgical and major medical complications related to TKA were 3% and 10%, respectively. The re-operation rate with readmission was 3% while no TKA was revised. The 30-day and one year mortality was 1% and 3%, respectively. The pre- to one year post-operative QALY improved significantly (p < 0.01). The cumulative QALY five years after TKA was four years. Assuming that these patients did not undergo TKA, their cumulative QALY at five years would have been only two years. CONCLUSION: TKA is an effective procedure for the treatment of end-stage osteoarthritis in patients who exceeded their estimated life expectancy. TKA provided significant improvement in function and quality of life without adversely affecting overall morbidity and mortality. Therefore, TKA should not be contra-indicated in elderly patients based on their advanced age alone.

Total hip arthroplasty through the direct anterior approach with and without the use of a traction table: a matched-control, retrospective, single-surgeon study.

BACKGROUND: Hip surgeons performing total hip arthroplasty (THA) through the direct anterior approach (DAA) commonly use a traction table to facilitate exposure. Even though performing THA through DAA without a traction table could be technically more demanding, this technique offers the advantage of intraoperative leg length comparison. Therefore, this study aimed to compare clinical outcomes, complication rates, component positioning, and leg length discrepancy (LLD) after THA through the DAA performed with or without a traction table. METHODS: A single-surgeon continuous series of 75 patients who underwent DAA THA performed with a traction table was matched for gender, age, and BMI with 75 patients who underwent DAA THA performed without a traction table (male, 62; female, 88, with an average age of 68 years old). Clinical and radiological outcomes, intra- and postoperative complications, and LLD were retrospectively assessed. RESULTS: No statistically significant difference was detected in surgical time, hospital stay, Harris Hip Score (HHS), complication rates, and implant positioning between the two groups. Leg length restoration was significantly more accurate in the group performed without a traction table (2.4 ± 2 mm vs. 3.7 ± 3.1 mm; p value ≤ 0.05). No LLD > 10 mm was reported in the group performed without a traction table, whereas two cases (2.7%) were reported in those performed with a traction table. CONCLUSION: Performing THA through DAA without a traction table was associated with a significantly more accurate leg length restoration without a significant increase in the rates of intra- and postoperative complications.

Septic arthritis of the shoulder due to Ureaplasma urealyticum after emergency caesarean section: a case report.

BACKGROUND: Ureaplasma urealyticum is an intra-cellular bacterium frequently found colonizing the genital tract. Known complications include localized infections, which can result in premature deliveries. Septic arthritis due to U. urealyticum in healthy patients is exceptionally rare, although opportunistic septic arthritis in agammaglobulinemic patients have been reported. However, there are no reports of septic arthritis due to U. urealyticum following caesarean section or in the post-partum period. CASE PRESENTATION: A 38-year-old immunocompetent woman presented with severe right shoulder pain, 1 month following emergency caesarean section at 26 weeks of gestation for pre-eclampsia and spontaneous placental disruption with an uncomplicated post-operative recovery. Our suspicion of septic arthritis was confirmed with abundant pus following arthrotomy by a delto-pectoral approach. Awaiting culture results, empirical antibiotic treatment with intravenous amoxicilline and clavulanic acid was initiated. In spite of sterile cultures, clinical evolution was unfavorable with persistent pain, inflammation and purulent drainage, requiring two additional surgical débridement and lavage procedures. The 16S ribosomal RNA PCR of the purulent liquid was positive for U. urealyticum at 2.95 × 106 copies/ml, specific cultures inoculated a posteriori were positive for U. urealyticum. Levofloxacin and azithromycine antibiotherapy was initiated. Susceptibility testing showed an intermediate sensibility to ciprofloxacin and clarithromycin. The strain was susceptible to doxycycline. Following cessation of breastfeeding, we started antibiotic treatment with doxycycline for 4 weeks. The subsequent course was favorable with an excellent functional and biological outcome. CONCLUSIONS: We report the first case of septic arthritis due to U. urealyticum after caesarean section. We hypothesize that the breach of the genital mucosal barrier during the caesarean section led to hematogenous spread resulting in purulent septic arthritis. The initial beta-lactam based antibiotic treatment, initiated for a purulent arthritis, did not provide coverage for cell wall deficient organisms. Detection of 16S rRNA allowed for a correct microbiological diagnosis in a patient with an unexpected clinical course.

[Stress fractures]. / Les fractures de stress.

A stress fracture is a bony overuse lesion resulting from an imbalance between the osseous regeneration and resorption in favor of the second one. There are two different types, the fatigue fracture that affects mainly the young and active and appears after an abrupt increase of the constraints, and the insufficiency fracture that affects mainly the elderly suffering from a diminished bone density and appears typically during physiological constraints. A thorough screening of the patient's history is mandatory in diagnostics, and MRI is currently the imagery of choice. As the treatment is time consuming and depends on the risk of potential complications that may occur depending on the localization of the fracture, prevention is of key importance and requires a multidisciplinary approach.

Une fracture de stress constitue une lésion osseuse par usure qui résulte d'un déséquilibre entre la régénération et la résorption osseuse en favorisant celle-ci. Il existe deux types différents, la fracture de fatigue qui touche plutôt les sujets jeunes et actifs et qui apparaît lors d'une augmentation brutale des contraintes, et la fracture par insuffisance qui touche plutôt les personnes âgées atteintes d'une densité minérale osseuse diminuée et qui apparaît typiquement lors de contraintes physiologiques. L'anamnèse constitue l'un des points clés du diagnostic, et l'IRM est actuellement l'imagerie de choix. Comme le traitement est long et dépend du risque de complications potentielles pouvant survenir en raison de la localisation de la fracture, la prévention est d'une importance cardinale et nécessite une approche pluridisciplinaire.

Entrapment of the Sciatic Nerve Over the Femoral Neck Stem After Closed Reduction of a Dislocated Total Hip Arthroplasty.

Sciatic nerve injury is a rare but potentially extremely disabling complication of posterior dislocated total hip arthroplasty. Initial closed reduction is recommended followed by a careful neurovascular examination. This procedure and the following stability testing are usually safe and typically associated with a very low complication rate. We report the case of sciatic nerve entrapment around the neck of the femoral stem after closed reduction of a posteriorly dislocated total hip arthroplasty. Immediate postreduction palsy led to surgical exploration, identification, neurolysis of the sciatic nerve and safe reduction was performed. Patient outcome was marked by complete sensitive sciatic nerve recovery, but complete loss of motor sciatic nerve function. This case highlights the importance of careful postreduction neurovascular assessment and prompt surgical exploration when indicated.