Sanchez-Sotelo, Joaquin

Robotic-assisted reverse shoulder arthroplasty has recently entered early limited clinical use, with the goal of improving the execution of preoperative plans and reducing malposition outliers that increase complication rates and health-care costs. This Innovation article reviews the rationale for this technology, explores its potential impact, examines key implementation challenges, and highlights the future directions needed to determine its ultimate value.

Background: Tendon-bone healing after rotator cuff injury is, or remains, a clinical challenge. Purpose: To examine the role of intraoperative use of purified exosome products (PEPs) in the treatment of rotator cuff injuries and to assess the effect of PEP on supraspinatus tendon-bone healing after rotator cuff repair in a rat model. Study Design: Controlled laboratory study. Methods: This study used 120 Sprague-Dawley rats that underwent an acute supraspinatus tendon transection from the insertion, followed by repair using a single transosseous suture. They were divided into 3 groups: a control group that received only sutures, a TISSEEL group that used a commercially available fibrin sealant patch (TISSEEL) of approximately 0.5 cm 2 , and a PEP-TISSEEL group that used a similarly sized TISSEEL patch combined with PEP. Autopsies were performed at 1, 3, 6, and 8 weeks after surgery. Analyses were performed using molecular biological, biomechanical, and histological techniques. Results: At 6 weeks, the PEP-TISSEEL group achieved greater failure load (mean, 27.5 ± 5.3 N) than the control (mean, 16.4 ± 4.2 N; P = .012) and TISSEEL (mean, 23.4 ± 5.0 N; P = .041) groups, with superiority persisting at 12 weeks (27.2 ± 6.5 N vs 13.1 ± 2.6 N [ P = .002] for the control group and 21.1 ± 5.8 N [ P = .037] for the TISSEEL group). DigiGait showed earlier recovery of stride length and paw angle. Histology revealed organized collagen and reduced scarring, while molecular assays demonstrated early inflammatory modulation with subsequent upregulation of collagen type 1 or 3 and TGF-β, supporting accelerated tendon-bone healing. Conclusion: Intraoperative application of PEP-TISSEEL enhanced tendon-bone healing in a rat model by improving biomechanical strength, promoting enthesis-specific histological regeneration, and accelerating functional recovery as evidenced by gait analysis. Clinical Relevance: The intraoperative application of PEP combined with TISSEEL significantly enhances rotator cuff tendon healing by modulating early inflammation, promoting collagen synthesis, and improving biomechanical properties in a rat model. These findings suggest that PEP-based therapies could offer a promising adjunct in surgical repair, potentially reducing retear rates and improving functional outcomes in patients with rotator cuff injuries. Further clinical studies are warranted to translate these benefits into human applications.

Aims Total elbow arthroplasty (TEA) has shown favourable outcomes in the management of severely comminuted distal humeral fractures in low-demand elderly patients, leading to its increased use in recent years. Less is known about the outcomes of TEA when used for the failure of either internal fixation or conservative management, particularly whether not performing TEA acutely influences the options for further management if fixation fails. This systematic review aimed to assess the clinical and functional outcomes following TEA when used for the post-traumatic sequelae of a distal humeral fracture, and to compare these outcomes with those in patients with a distal humeral fracture who undergo TEA acutely. Methods MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and Scopus databases were searched from January 2000 to September 2024 for studies reporting complications, reoperations, the range of motion of the elbow, or functional outcomes following the use of TEA in the management of the post-traumatic sequelae of distal humeral fractures, including those due to failed fixation, nonunion, and post-traumatic arthritis. Demographic and clinical data were collected, descriptive statistics were summarized, and meta-analyses were undertaken to compare the outcomes between salvage and acute TEA. Results A total of 16 studies were included, with a total of 380 patients who underwent salvage TEA and 251 who underwent TEA as the initial management. Salvage TEA was associated with a significantly higher overall risk of complications (odds ratio (OR) 2.5 (95% CI 1.0 to 5.9)), though the rate of reoperations did not differ from those who underwent TEA acutely (OR 1.4 (95% CI 0.8 to 2.4)). Pooled analyses revealed a similar postoperative range of flexion (mean difference (MD) -2.4° (95% CI -9.1 to 4.3)) and extension of the elbow (MD 1.1° (95% CI -2.3 to 4.5)) and pronation (MD 0.0° (95% CI -1.1 to 1.1)) and supination (MD -0.0° (95% CI -1.0 to 0.9)) of the forearm. However, salvage TEA showed significantly inferior functional outcomes, as assessed by the Mayo Elbow Performance Score (MD 9.7 (95% CI -18.8 to -0.6)). Conclusion These findings indicate that salvage TEA represents a viable option for the management of post-traumatic sequelae following the teatment of a distal humeral fracture, although patients who underwent salvage TEA had a significantly increased rate of complications and significantly inferior functional outcomes compared with those who underwent TEA acutely. Cite this article: Bone Joint J 2026;108-B(1):21–29.

Aims Arthrofibrosis affects a notable percentage of patients after total knee arthroplasty (TKA). Elevated serum mast cell tryptase (SMCT) levels have been linked to fibrosis, suggesting that SMCT could serve as a biomarker for arthrofibrosis. As such, the aims of this study were to assess SMCT levels in TKA patients, and their possible association with arthrofibrosis and clinical outcomes in a prospective clinical trial. Methods We conducted a prospective study involving 219 patients undergoing primary TKA at a single academic medical centre between January 2018 and December 2022. SMCT levels were measured preoperatively, immediately postoperatively, and at six weeks, three months, and one year postoperatively. Secondary outcomes included revision rates, complications, and Knee Society Scores (KSSs). Allergic and inflammatory conditions were assessed for their influence on SMCT levels. Results At one year postoperatively, eight patients had developed arthrofibrosis (4%), and three (1.5%) had undergone manipulation under anaesthesia. The mean preoperative SMCT level was 5.6 µg/L (SD 3.4), which decreased significantly to 4.1 µg/L (SD 2.7) immediately postoperatively (p < 0.001). At six weeks the mean SMCT level was 6.4 µg/l (SD 4.1), and was 6.1 µg/l at both three months (SD 4.1) and one year (SD 4.0). Elevated preoperative SMCT levels were not significantly associated with the risk of arthrofibrosis development (OR 3; p = 0.370), nor were immediate postoperative levels (OR 2; p = 0.754) or those at six weeks (OR 1; p = 0.989). Of note, elevated SMCT levels at three months (OR 5; 95% CI 0.4 to 64; p = 0.191) and one year (OR 13; 95% CI 1 to 232; p = 0.077) trended toward an increased risk of arthrofibrosis development, without reaching significance. Conclusion In patients undergoing TKA, with the numbers included in this study, there was no significant difference in SMCT levels between patients who did and did not develop arthrofibrosis at any timepoint. However, there was a trend towards elevated SMCT levels at three months and one year in those who developed arthrofibrosis, which merits further study. Cite this article: Bone Joint Res 2025;14(11):1045–1052.

Arthrofibrosis is a common complication following total knee arthroplasty and is the result of a dysregulated immuno-inflammatory cascade, which culminates in excessive scar deposition by myofibroblasts within the knee joint. Pharmacotherapies for arthrofibrosis are limited, with treatment reliant on manipulation under anesthesia or lysis of adhesions with or without component revision. Bupivacaine (a local anesthetic) and meloxicam (a nonsteroidal anti-inflammatory drug) combination therapy may exert antifibrotic properties by limiting inflammatory cell recruitment and the subsequent release of profibrotic cytokines. The purpose of this study was to evaluate the effects of this combination therapy in a rabbit model of arthrofibrosis by evaluating live and postsacrifice knee biomechanics and gene expression of posterior knee capsule tissue. Forty New Zealand white rabbits were equally divided into two experimental groups and prospectively studied to assess knee passive extension angles (PEA), terminal posterior capsular stiffness, and the inflammatory milieu of the posterior knee joint capsule. Experimental limbs with and without combination therapy showed similar live PEAs and terminal posterior capsular stiffness, with no significant differences between the groups. Gene expression analysis, however, revealed significant reduction in inflammatory genes but not profibrotic genes. In summary, bupivacaine and meloxicam combination therapy did not exert antifibrotic effects in a rabbit model of arthrofibrosis but significantly reduced the expression of inflammatory markers in the local environment of the posterior capsule.

AimsTo characterize the effects of varying experimental parameters of transforming growth factor-beta 1 (TGF-β1) in primary knee fibroblasts as an in vitro model of arthrofibrosis.MethodsPrimary knee fibroblasts were isolated from one patient undergoing primary total knee arthroplasty (TKA) and one patient undergoing revision TKA for arthrofibrosis, respectively. Fibroblasts were stimulated with varying concentrations and durations of the pro-fibrotic cytokine TGF-β1. Picrosirius red staining (PSR) was conducted to assess collagen deposition, and real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting were performed to determine cellular gene expression levels. A collagen gel contraction assay was used to assess TGF-β1-induced fibroblast contraction.ResultsIn our experiments, TGF-β1-mediated collagen deposition was consistent across a vast concentration range (0.5 to 40 ng/ml). While α-smooth muscle actin (ACTA2) protein levels and SMAD2 phosphorylation were induced by low concentrations (1 ng/ml), robust ACTA2 transcription required higher concentrations (5 ng/ml) of TGF-β1. Evaluation of TGF-β1-mediated cell and cytoskeletal contractility shows that in the measured fibroblasts, this process occurs within three hours following TGF-β1 administration. Of note, TGF-β1-differentiated myofibroblasts exhibited greater contractile properties than naïve fibroblasts in the presence of TGF-β1.ConclusionTaken together, this study elucidates key TGF-β1 experimental parameters that will inform the development and interpretation of in vitro models of arthrofibrosis.Cite this article: Bone Joint Res 2025;14(6):527–538.

Experimental analyses of knee joint contractures have traditionally utilized a 6-month rabbit model as the gold standard. However, this model is time-intensive and costly. The purpose of this study was to develop an abbreviated rabbit model of knee contractures and compare it to the well-established longer model. Twenty female New Zealand White rabbits were divided into two equal groups and prospectively studied to assess knee passive extension angles (PEA), contracture angles (CA), and terminal posterior capsular stiffness. Experimental knees were immobilized for either 4 weeks ( n = 10) with an 8-week remobilization period in the abbreviated model (i.e., 3 months) or for 8 weeks ( n = 10) with a 16-week remobilization period in the standard model (i.e., 6 months). PEAs were assessed at remobilization and several time points using differing vertical forces. At sacrifice, terminal biomechanical data were collected to assess posterior capsular stiffness. Analysis of PEAs in live animals at each torque value and time point demonstrated increased PEAs and decreased CAs in the 3-month abbreviated model as compared to the 6-month standard model. At sacrifice, biomechanical analysis demonstrated that the posterior capsules of the 3-month experimental limbs were significantly more stiff than the contralateral limb (2.4 vs. 0.05 Ncm/°, p < 0.0001), but significantly less stiff compared to the 6-month experimental limbs (2.4 vs. 4.7 Ncm/°, p < 0.0001). Our study suggests that the 6-month standard rabbit knee model of arthrofibrosis should continue to be used in the laboratory assessment of arthrofibrosis. However, the abbreviated model may be beneficial under selected experimental conditions.

AimsTo evaluate the role of autophagy in primary knee fibroblasts undergoing myofibroblast differentiation as an in vitro model of arthrofibrosis, a complication after total knee arthroplasty characterized by aberrant intra-articular scar tissue formation and limited range of motion.MethodsWe conducted a therapeutic screen of autophagic-modulating therapies in primary human knee fibroblasts undergoing transforming growth factor-beta 1 (TGF-β1)-mediated myofibroblast differentiation. Autophagy was induced pharmacologically with rapamycin or by amino acid deprivation. Picrosirius red staining was performed to quantify collagen deposition. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were conducted to evaluate fibrotic gene expression levels.ResultsRapamycin, an mTOR complex 1 (mTORC1) inhibitor and autophagy inducer, reduced TGF-β1-mediated collagen deposition. Interestingly, we simultaneously report that myofibrogenic genes, including ACTA2, were highly upregulated following rapamycin-TGF-β1 treatment. When autophagy was induced through amino acid deprivation, we demonstrated suppressed extracellular matrix levels, fibrotic gene expression (e.g. ACTA2), and SMAD2 phosphorylation levels in TGF-β1-stimulated fibroblasts.ConclusionOur findings demonstrate that the induction of cellular autophagy suppresses TGF-β1-induced collagen deposition in primary human knee fibroblasts. Taken together, these data suggest that cellular autophagy may be prophylactic against the pathogenesis of arthrofibrosis.Cite this article: Bone Joint Res 2025;14(4):328–337.

Background: No biomechanical study has established the effect of different graft positions or bone block options on anterior glenohumeral joint stability. Purpose/Hypothesis: The purpose of this study was to compare graft choice (distal clavicular vs coracoid autograft for Latarjet) and position on stability of the bone block for anterior glenohumeral instability. It was hypothesized that both grafts would be comparable if flush with the glenoid but that the sling effect of the Latarjet procedure would lead to greater stability in case of graft medialization. Study Design: Controlled laboratory study. Methods: Eight cadaveric shoulders were included. Defects stabilized using a distal clavicular graft and a coracoid graft were consecutively positioned at 0, 4, and 8 mm medially. The starting position was determined by the humeral head’s being seated at its most medial position on the glenoid surface. Each experiment comprised maximal external rotation and glenohumeral abduction at 60° while applying a constant 50-N medial compressive force to the humerus under all conditions. The conjoint tendon was routed through a split in the subscapularis and loaded with a 5-N weight using a pulley system for all Latarjet trials to simulate the sling effect. Results: Regarding the clavicular graft, the stability ratio significantly decreased versus the intact condition at all medial offsets ( P = .007 for 0 mm, P < .001 for 4 mm, and P < .001 for 8 mm), and it was significantly lower in the 4-mm versus 0-mm position ( P = .008), significantly higher in the 4-mm versus 8-mm position ( P < .001), and significantly lower in the 8-mm versus 0-mm position ( P < .001). Regarding the coracoid graft, the stability ratio was comparable with intact for the 0-mm position ( P = .12), while it was significantly lower in the 4-mm and 8-mm positions ( P < .001 for both). The distal clavicular graft at 0-mm offset was comparable with the coracoid graft at 0-mm offset. Conclusion: In shoulders with anterior glenoid bone loss, the coracoid and distal clavicular autografts were biomechanically comparable when placed flush with the glenoid. The distal clavicle at 0-mm offset did not restore stability compared with the intact specimen, but the Latarjet at 0-mm offset was not significantly different from the intact condition. Clinical Relevance: The Latarjet procedure provides higher stability compared with distal clavicular autograft when medialized.

Background: Surgical repair of full thickness biceps tears has demonstrated adequate outcomes in short and mid-term studies. However, data on the long-term outcomes of full thickness distal biceps injuries and their treatment are currently lacking. Purpose/Hypothesis: The purpose of this study was to report on patient demographics, injury characteristics, and long-term outcomes for patients with full-thickness distal biceps tears. It was hypothesized that complete distal biceps tears managed operatively would demonstrate robust clinical success at long-term follow-up. Study Design: Case series; Level of evidence, 4. Methods: Patients with magnetic resonance imaging–confirmed, complete distal biceps tendon rupture sustained between 1996 and 2016 were identified. Patients were cross-referenced with a regional geographic database. Results: A total of 66 patients (3 female, 63 male) with a median age of 50.8 years (IQR, 41.5-60.4) and a median clinical follow-up of 14.7 years (IQR, 9.6-17.9 years) were included. Patients who sustained a full-thickness distal biceps tendon tear were likely to be in their early 50s, male, right-hand dominant, current/former smokers, and laborers with a history of traumatic injury during an intentional movement. Most of these patients had pain and supination weakness but no loss of range of motion. All included tears were treated operatively. At final follow-up, patients maintained a majority of near-normal range of motion (median total arc of flexion/extension 140° and supination/pronation 80°), excellent elbow flexion strength (91% of patients had full strength), and adequate elbow supination strength (76% of patients had full strength). The overall complication rate was 24%, with 16 out of 66 patients experiencing some type of complication between infection, rerupture, heterotopic ossification, reoperation, and nerve complications. Overall return to work was 98%, and 85% of those who returned to work did so without restrictions. Conclusion: Complete tears of the distal biceps were most common in patients 50 years of age, male sex, right-hand dominant, and current/former smokers. The most common profession was laborer, and injuries were primarily traumatic in nature during intentional activity. Patients managed operatively demonstrated high rates of success at long-term follow-up with respect to elbow function and clinical outcomes.