Contemporary outcomes of tibial tubercle osteotomy for revision total knee arthroplasty.

Aims: Tibial tubercle osteotomy (TTO) facilitates surgical exposure and protects the extensor mechanism during revision total knee arthroplasty (rTKA). The purpose of this study was to determine the rates of bony union, complications, and reoperations following TTO during rTKA, to assess the functional outcomes of rTKA with TTO at two years' minimum follow-up, and to identify the risk factors of failure. Methods: Between January 2010 and September 2020, 695 rTKAs were performed and data were entered into a prospective database. Inclusion criteria were rTKAs with concomitant TTO, without extensor mechanism allograft, and a minimum of two years' follow-up. A total of 135 rTKAs were included, with a mean age of 65 years (SD 9.0) and a mean BMI of 29.8 kg/m2 (SD 5.7). The most frequent indications for revision were infection (50%; 68/135), aseptic loosening (25%; 34/135), and stiffness (13%; 18/135). Patients had standardized follow-up at six weeks, three months, six months, and annually thereafter. Complications and revisions were evaluated at the last follow-up. Functional outcomes were assessed using the Knee Society Score (KSS) and range of motion. Results: The mean follow-up was 51 months (SD 26; 24 to 121). Bony union was confirmed in 95% of patients (128/135) at a mean of 3.4 months (SD 2.7). The complication rate was 15% (20/135), consisting of nine tibial tubercle fracture displacements (6.7%), seven nonunions (5%), two delayed unions, one tibial fracture, and one wound dehiscence. Seven patients (5%) required eight revision procedures (6%): three bone grafts, three osteosyntheses, one extensor mechanism allograft, and one wound revision. The functional scores and flexion were significantly improved after surgery: mean KSS knee, 48.8 (SD 17) vs 79.6 (SD 20; p < 0.001); mean KSS function, 37.6 (SD 21) vs 70.2 (SD 30; p < 0.001); mean flexion, 81.5° (SD 33°) vs 93° (SD 29°; p = 0.004). Overall, 98% of patients (n = 132) had no extension deficit. The use of hinge implants was a significant risk factor for tibial tubercle fracture (p = 0.011). Conclusion: TTO during rTKA was an efficient procedure to improve knee exposure with a high union rate, but had significant specific complications. Functional outcomes were improved at mid term.

Tibial Tubercle Osteotomy in Revision Total Knee Arthroplasty for Periprosthetic Infection: Indications and Outcomes.

BACKGROUND: Adequate exposure is essential in revision total knee arthroplasty (RTKA). Tibial tubercle osteotomy (TTO) enhances exposure, but its use is controversial in the setting of periprosthetic infection. The purposes of this study were to determine (1) the rates of complications and revisions due to TTO during RTKA in the setting of a periprosthetic infection, (2) the rate of septic failure, and (3) functional outcomes at a minimum 2-year follow-up. METHODS: A single-center retrospective study from 2010 to 2020 was performed. The cases of a total of 68 patients who received a TTO during RTKA in the setting of periprosthetic infection with a minimum follow-up of 2 years (mean, 53.3 months; range, 24 to 117 months) were analyzed. Complications and revisions due to TTO were reported. The functional outcomes were assessed using the Knee Society Score (KSS) and range of motion. RESULTS: Seven knees (10.3%) had complications secondary to the TTO (3 had fracture-displacement of the TTO; 2, nonunion; 1, delayed union; and 1, wound dehiscence). The mean time to union (and standard deviation) was 3.8 ± 3.2 months (range, 1.5 to 24 months). Two knees (2.9%) underwent a TTO-related revision (1 had wound debridement, and 1 had tibial tubercle osteosynthesis). Eighteen knees (26.5%) had recurrence of infection requiring revision: 17 were managed with debridement, antibiotics, and implant retention (DAIR), and 1 had 2-stage RTKA. Flexion improved after surgery (from a mean of 70° to a mean of 86°; p = 0.009), as did the KSS knee (46.6 to 79; p < 0.001) and function (35.3 to 71.5; p < 0.001) subscores. Overall, 42.6% of infected knees managed with RTKA with the TTO procedure were considered successful without any complication at the last follow-up. Only 2 knees (2.9%) required revision related to the TTO. CONCLUSIONS: TTO in RTKA involving periprosthetic infection is an effective surgical exposure aid and has excellent rates of union (97.1%) despite the presence of infection. However, the risk of failure because of persistent or recurrent infection remains high in the first 2 years following RTKA for infection. LEVEL OF EVIDENCE: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Tibial tubercule osteotomy during the revision of total knee arthroplasty: The technique of a referral center with 10 years of experience.

INTRODUCTION: The Tibial Tubercle Osteotomy (TTO) technique, by lifting the distal bony attachment of the extensor mechanism, allows efficient knee exposure while preserving soft tissues and tendinous attachments. The surgical technique seems essential to obtain satisfying outcomes with a low rate of specific complications. Several tip sand tricks can be used to improve this procedure during the revision of total knee arthroplasty (RTKA). TECHNIQUE: The osteotomy should be at least: 60 mm in length and 20 mm in width to allow fixation with 2 screws; and 10-15 mm thick to resist to screw compression. The proximal cut of the osteotomy must keep a proximal buttress spur of 10 mm to get primary stability and avoid the tubercle ascension. A smooth end of the TTO distally reduces the risk of a tibial shaft fracture. The strongest fixation is obtained using two bicortical 4.5 mm screws slightly ascendant. RESULTS: From January 2010 to September 2020, 135 patients received an RTKA with concomitant TTO and a mean follow-up of 51 ± 26 months [24-121]. The osteotomy was healed in 95% of patients (n = 128) with a mean delay of 3.4 ± 2.7 months [1.5-24]. However, there are some specific and significant complications related to the TTO. Twenty complications (15%) related to the TTO were recorded, with 8 (6%) requiring surgery. CONCLUSION: Tibial tubercle osteotomy in RTKA is an efficient procedure to improve knee exposure. To avoid tibial tubercle fracture or non-union, a rigorous surgical technique is primordial with a sufficient length and thickness of the tibial tubercle, a smooth end, a proximal step, a final good bone contact, and a strong fixation.

How often do we need offset stems for revision total knee arthroplasty? About a consecutive series of 789 knees.

INTRODUCTION: This study aimed to determine the incidence of offset stem usage in revision total knee arthroplasty (rTKA), and to assess the necessity for their use with the femoral and tibial components. METHODS: This retrospective radiological study included 862 patients who underwent rTKA between 2010 and 2022. Patients were divided into a non-stem group (group NS), offset stem group (group OS), and straight stem group (group SS). Two senior orthopedic surgeons evaluated all the post-operative radiographs of the group OS to assess the necessity of offset use. RESULTS: In total, 789 patients met all eligibility inclusion criteria and were reviewed (305 males (38.7%)) with a mean age of 72.7 ± 10.2 years old [39; 96]. Eighty-eight (11.1%) patients had undergone rTKA with offset stems (34 tibia, 31 femur, 24 both) and 609 (70.2%) with straight stems. The tibial and femoral stems were diaphyseal of over 75 mm in 83 revisions (94.3%) for group OS and 444 revisions (72.9%) for group SS (p < 0.001). Offset in the tibial component was located medially in 50% of rTKA, while the offset in the femoral component was placed anteriorly in 47.3% of the rTKA. Assessment by the two independent senior surgeons found stems were only necessary in 3.4% of cases. Offset stems were only required for the tibial implant. DISCUSSION: Offset stems were used in 11.1% of revision total knee replacements, however, they were deemed necessary in 3.4% and for the tibial component only.

Image-based robotic unicompartmental knee arthroplasty allowed to match the rotation of the tibial implant with the native kinematic knee alignment.

PURPOSE: Image-based robotic tools improve the accuracy of unicompartmental knee arthroplasty (UKA) positioning, but few studies have examined its effect on axial alignment. The aim of this study was to compare the characteristics of tibial and femoral implant positioning, mainly the tibial rotation, during medial or lateral UKA, performed with an image-based robotic assisted system. METHODS: A total of 71 UKA performed between September 2021 and June 2022 (53 medial and 18 lateral) were analyzed. All data regarding implant positioning (rotation, coronal and sagittal alignment) for tibial and femoral components were obtained using MAKO® software (Stryker®, Mahwah, USA) intra-operatively. RESULTS: The lateral UKA had a mean internal tibial rotation of 15.4 ± 3°, a mean external femoral rotation of 0.96 ± 2.4°, and a mean tibial slope of 4.7 ± 1.3°. The medial UKA had a mean internal tibial rotation of 0.18 ± 2.7°, a mean internal femoral rotation of 0.35 ± 2.2°, and a mean tibial slope of 5.4 ± 1.3°. The tibial rotations, femoral valgus, tibial varus and tibial size significantly differed between medial and lateral UKA (p < 0.05). There was no significant difference in femoral rotation, flexion, femoral size, slope, and polyethylene thickness between medial and lateral UKA. CONCLUSION: Medial and lateral UKA had significantly different implantation characteristics related to the biomechanics of the knee compartments. Image-based robotic UKA allowed precise femorotibial positioning per-operatively to match native kinematic alignment.

Dual mobility cups associated with proximal femoral replacement in nontumoral indications: Results and complications.

INTRODUCTION: Reconstruction of extensive proximal femoral bone loss is a major challenge during total hip arthroplasty (THA). Proximal femoral replacement (PFR), initially used for bone tumors, is an alternative to allograft-prosthetic composite reconstruction. However, PFRs present a high complication rate, particularly related to dislocation. Moreover, dual mobility cups (DMCs) are effective in preventing dislocation, and no study has yet assessed their association with PFRs. Therefore, the aim of this study was to assess the dislocation and complication rates in THA using PFRs with DMCs. HYPOTHESIS: The use of a DMC decreases the dislocation rate associated with PFRs in nontumoral indications. METHODS: From 2008 to 2017, 66 PFRs associated with a DMC (40 women, mean age=71 years [26-94]) were included in our total joint registry and retrospectively reviewed. The main indications were complex periprosthetic and pertrochanteric fractures (26 THAs, 40%), aseptic loosening (22 THAs, 33%) and periprosthetic joint infections (18 THAs, 27%). A single design of PFR implant was used (Global Modular Replacement System (GMRS), Stryker, Mahwah, NJ, USA) with an uncemented stem in 54 THAs (82%). RESULTS: Eighteen complications (27%) were reported at a mean follow-up of 4.6 years [2-10]: 5 dislocations (7.5%), 9 periprosthetic joint infections (13.6%), 2 aseptic loosening (3%) and 2 femur fractures (3%). Overall survivorship at 5 years was 72% (95% CI: 58-82). Survivorship free from dislocation was 94% (95% CI: 85-98) at 1 year. The mean Harris Hip Score was 70±16.4 [26-100] at latest follow-up. CONCLUSION: The use of DMCs limits the risk of PFR dislocation, in comparison to other series in the literature that used large femoral heads, without compromising implant survivorship. In addition, DMCs make it possible to overcome the potential risks of mechanical failure associated with constrained acetabular components. LEVEL OF EVIDENCE: IV; retrospective cohort.

Spinopelvic parameters in greater trochanteric pain syndrome: a retrospective case-control study.

PURPOSE: Greater trochanteric pain syndrome (GTPS) is a condition resulting in lateral hip pain, most commonly caused by tendinosis or tear of the gluteus medius and minimus tendons, and greater trochanteric bursitis. Our aim was to assess pelvic parameters and proximal femoral anatomy in patients suffering from surgical-stage GTPS compared with a control group. METHODS: This retrospective, case-control study assessed 43 patients suffering from GTPS, matched according to age, gender, body mass index and level of sport and physical activity to 43 control patients, between 2013 and 2018. Pelvic parameters, including pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS), and proximal femoral anatomy, including femoral offset (FO) and neck-shaft angle (NSA), were measured using the EOS Imaging™ system. RESULTS: GTPS patients had a significantly lower mean (± SD) SS than control patients (33.1 ± 10.4 vs. 39.6 ± 9.7°, respectively; p < 0.05). There was no significant difference in PT (21.3 ± 7.1 vs. 19.0 ± 7.2°), PI (53.5 ± 11.6 vs. 57.7 ± 10.5°), FO (40.4 ± 8 vs. 42.2 ± 6.8°) or NSA (125.1 ± 5.8 vs. 124.4 ± 4.7°). There was no difference in lower back pain symptoms in a subgroup analysis of GTPS patients. CONCLUSIONS: Sacral slope was lower in patients with surgical-stage GTPS than in asymptomatic hip patients, using the EOS Imaging™ system.

Recombinant BCG Expressing ESX-1 of Mycobacterium marinum Combines Low Virulence with Cytosolic Immune Signaling and Improved TB Protection.

Recent insights into the mechanisms by which Mycobacterium tuberculosis, the etiologic agent of human tuberculosis, is recognized by cytosolic nucleotide sensors have opened new avenues for rational vaccine design. The only licensed anti-tuberculosis vaccine, Mycobacterium bovis BCG, provides limited protection. A feature of BCG is the partial deletion of the ESX-1 type VII secretion system, which governs phagosomal rupture and cytosolic pattern recognition, key intracellular phenotypes linked to increased immune signaling. Here, by heterologously expressing the esx-1 region of Mycobacterium marinum in BCG, we engineered a low-virulence, ESX-1-proficient, recombinant BCG (BCG::ESX-1Mmar) that induces the cGas/STING/TBK1/IRF-3/type I interferon axis and enhances AIM2 and NLRP3 inflammasome activity, resulting in both higher proportions of CD8+ T cell effectors against mycobacterial antigens shared with BCG and polyfunctional CD4+ Th1 cells specific to ESX-1 antigens. Importantly, independent mouse vaccination models show that BCG::ESX-1Mmar confers superior protection relative to parental BCG against challenges with highly virulent M. tuberculosis.