New augmented reality remote for virtual guidance and education of fracture surgery: a retrospective, non-inferiority, multicenter cohort study.

BACKGROUND: The demand for telesurgery is rapidly increasing. Augmented reality (AR) remote surgery is a promising alternative, fulfilling a worldwide need in fracture surgery. However, previous AR endoscopic and Google Glass remotes remain unsuitable for fracture surgery, and the application of remote fracture surgery has not been reported. We aimed to evaluated the safety and clinical effectiveness of a new AR remote in fracture surgery. MATERIALS AND METHODS: This retrospective non-inferiority cohort study was conducted at three centres. Between January 1, 2018, and March 31, 2022, 800 patients who underwent fracture surgery were eligible for participation. The study enrolled 551 patients with fractures (132 patellae, 128 elbows, 126 tibial plateaus, and 165 ankles) divided into an AR group (specialists used AR to remotely guide junior doctors to perform surgeries) and a traditional non-remote group (specialists performed the surgery themselves). RESULTS: Among 364 patients (182 per group) matched by propensity score, seven (3.8%) in the AR group and four (3%) in the non-remote group developed complications. The 0.005 risk difference (95% confidence interval: -0.033 to 0.044) was below the pre-defined non-inferiority margin of a 10% absolute increase. A similar distribution in the individual components of all complications was found between the groups. Hierarchical analysis following propensity score matching revealed no statistical difference between the two groups regarding functional results at 1-year follow-up, operative time, amount of bleeding, number of fluoroscopies, and injury surgery interval. A Likert scale questionnaire showed positive results (median scores: 4-5) for safety, efficiency, and education. CONCLUSION: This study is the first to report that AR remote surgery can be as safe and effective as that performed by a specialist in person for fracture surgery, even without the physical presence of a specialist, and is associated with improving the skills and increasing the confidence of junior surgeons. This technique is promising for remote fracture surgery and other open surgeries, offering a new strategy to address inadequate medical care in remote areas.

Biomechanical consequences of proximal screw placement in minimally invasive surgery for hallux valgus correction.

Hallux valgus is one of the most common surgically corrected forefoot deformities. Studies evaluating clinical outcomes of minimally invasive chevron and akin (MICA) procedure have shown shorter operation time, faster recovery, and smaller scars compared to the open approach. Previous biomechanical cadaveric studies have largely focused on the open approach with minimal on MICA. To our knowledge, no studies have compared different proximal screw placements in MICA which can either be three-point fixation or intramedullary. This study aims to compare the biomechanical properties of fixation between these two techniques in MICA. Six matched pairs of human fresh frozen cadaveric feet were randomized to either three-point fixation or intramedullary groups. Both procedures were performed by a single fellowship-trained orthopaedic foot and ankle surgeon. Using a material testing machine, each specimen underwent 1000 cycles of plantar-to-dorsal uniaxial loads from 0 to 31 N in cantilever configuration while monitoring bending stiffness and distal fragment dorsal angulation. They were then subjected to load until failure at a compression rate of 10 mm/min. Specimens from both groups tolerated the walking fatigue test. Mean bending stiffness of three-point fixation was 84% higher than intramedullary constructs (P=0.002). Mean dorsal angulation of intramedullary was thrice that of three-point fixation constructs (P=0.008). Mean load to failure of three-point fixation was 30% higher than intramedullary constructs (P=0.001). Three-point fixation provide superior biomechanical stability compared to intramedullary proximal screw placement. The surgical technique using three-point proximal screw fixation can offer robust fixation and lead to better clinical outcomes. LEVEL OF CLINICAL EVIDENCE: 5.

Determining patient acceptable symptom states from patient reported outcome measures following reverse shoulder arthroplasty: Constant-murley, UCLA, Oxford Shoulder Scores.

Aims: To establish cut-off values for Patient-Acceptable Symptom States (PASS) in three Patient Reported Outcome Measures (PROMs), the Constant-Murley Score (CMS) and University of California Los Angeles (UCLA) Shoulder Score and Oxford Shoulder Score (OSS) at 3, 6, and 12-months following reverse shoulder arthroplasty (RSA). Methods: A retrospective study was conducted for individuals who were treated for massive rotator cuff tear, rotator cuff arthropathy or proximal humerus fractures with RSA from January 2011 and February 2020. This study included patients who have completed the patient reported outcome measures (PROMs) and satisfaction questions preoperatively, and at 3, 6 and 12-months after the procedure. Functional outcome were evaluated by CMS, UCLA shoulder score and OSS, with one anchoring question regarding satisfaction. PASS thresholds for each PROM were obtained with the Youden method, by using the receiver operating characteristic analysis, and secondary analysis was performed with the 80% specificity and 75th percentile method. Results: 129 patients were included. 74.2%, 83.9%, and 89.3% of patients were found to have a satisfactory symptom state at 3, 6 and 12-months postoperatively. At 3, 6 and 12-month intervals, the respective PASS thresholds were 42, 39 and 52 for CMS, 17, 21 and 26 for UCLA score and 28, 25 and 18 for OSS. Conclusions: PASS thresholds for RSA at 3, 6 and 12-months were found for CMS (42, 39, 52), UCLA (17, 21, 26) and OSS (28, 25, 18). These thresholds suggest increasing expectations with a trend towards higher functional requirements at each time point.

Functional outcome of direct anterior versus posterior approach in total hip arthroplasty: a propensity-matched Asian study.

INTRODUCTION: The direct anterior approach (DAA) to total hip arthroplasty (THA) is a surgical approach that minimises soft tissue trauma, resulting in faster rehabilitation when compared to a posterior approach (PA). This study aimed to evaluate the difference between the two groups in an Asian cohort using propensity score matching. METHODS: A retrospective review of prospectively collected registry data of 794 primary THAs was performed. The effects on patients with DAA THA versus patients with PA THA were investigated. Propensity scores were generated using logistic regression to adjust for confounding variables of age, gender, body mass index and diagnosis. Data analysis was performed, and statistical significance was defined as a P value < 0.05. RESULTS: The average length of stay (LOS) for the PA group and DAA group was 5.4 days and 2.9 days, respectively (P < 0.001). One (1.9%) patient from the PA group suffered a posterior dislocation 6 months after surgery and subsequently underwent revision surgery 2 years later. No dislocations were detected in the DAA group. The DAA group had better functional outcome, satisfaction and expectation scores at 6 months and 2 years. CONCLUSION: In this study, patients who underwent DAA THA had better functional outcome at 2 years and almost 2 days shorter overall LOS than those who underwent PA THA. Therefore, the DAA to THA is a novel technique that has shown improved functional outcomes, with fewer complications compared to PA THA.

The double-lasso loop technique of Biceps tenodesis has lower displacement after cyclic loading, compared to interference screw fixation: Biomechanical analysis in an ovine model.

Background: Biceps tenodesis is an effective treatment for symptomatic long head of biceps tendon pathology. Recently the arthroscopic "double lasso-loop" suture anchor (DLSA) technique was described, advantaged by reduced cost, complexity, and operative time. We aimed to compare the in vitro strength of DLSA with conventional interference screws (IS). Methods: A biomechanical analysis was conducted on 14 sheep shoulders (8 DLSA, 6 IS), consisting of a 500-cycle cyclic loading experiment of 5-70 N and ultimate failure load (UFL) test where each specimen was pulled until failure. Displacement (mm) was recorded every 100 cycles, while stiffness and UFL were observed. Results: Cyclic displacement was significantly lower with DLSA at 100 cycles, but not above. During the UFL test, IS was stiffer (27.68 ± 6.56 N/mm versus 14.10 ± 5.80 N/mm, p = .005) and had higher UFL (453.67 ± 148.55 N versus 234.22 ± 44.57 N, p = .001) than DLSA. All DLSA failures occurred with suture/anchor pull-out, while all IS constructs failed at the muscle/tendon. Discussion: Comparison of the novel DLSA technique with a traditional IS method found lower initial displacement. While our IS constructs could withstand higher UFL, peak load characteristics of DLSA were similar to previous ovine studies. Hence, the DLSA technique is a viable alternative to IS for biceps tenodesis with its purported non-biomechanical advantages.

Rotator cuff repair with an interposition polypropylene mesh: A biomechanical ovine study.

BACKGROUND: Chronic large to massive rotator cuff tears are difficult to treat and re-tears are common even after surgical repair. We propose using a synthetic polypropylene mesh to increase the tensile strength of rotator cuff repairs. We hypothesize that using a polypropylene mesh to bridge the repair of large rotator cuff tears will increase the ultimate failure load of the repair. AIM: To investigate the mechanical properties of rotator cuff tears repaired with a polypropylene interposition graft in an ovine ex-vivo model. METHODS: A 20 mm length of infraspinatus tendon was resected from fifteen fresh sheep shoulders to simulate a large tear. We used a polypropylene mesh as an interposition graft between the ends of the tendon for repair. In seven specimens, the mesh was secured to remnant tendon by continuous stitching while mattress stitches were used for eight specimens. Five specimens with an intact tendon were tested. The specimens underwent cyclic loading to determine the ultimate failure load and gap formation. RESULTS: The mean gap formation after 3000 cycles was 1.67 mm in the continuous group, and 4.16 mm in the mattress group (P = 0.001). The mean ultimate failure load was significantly higher at 549.2 N in the continuous group, 426.4 N in the mattress group and 370 N in the intact group (P = 0.003). CONCLUSION: The use of a polypropylene mesh is biomechanically suitable as an interposition graft for large irreparable rotator cuff tears.

Reduction of geometric misfit in straight antegrade humeral nailing by evaluating the effect of entry point angulation using a three-dimensional computational analysis.

BACKGROUND: Straight antegrade intramedullary nails are generally inserted utilising the apex as the surgical entry point in accordance with the mechanical axis of the bone. Our objective is to optimise the bone-nail fit in intramedullary nailing by subjecting the surgical entry point to varying angulations in both the mediolateral and anterior-posterior directions via a quantitative fit assessment in each configuration to identify the optimal angulation, defined as the angulation with the lowest occurrence of thin-out to improve nail fitting within the humerus. METHODS: Computed tomography (CT) scans from 10 cadaveric humeri models were used to generate three-dimensional bone models. The centreline profile of each humerus model was determined by dividing the humerus into multiple slices and identifying its respective centroid. The guidewire and nail models were then established and inserted into the humerus using the apex as the standard entry point. The bone-nail fit was measured utilising three fit quantification parameters: thin-out distance, nail protrusion volume into the cortical shell and deviation distance (top, middle, bottom) between the nail's longitudinal axis and medullary cavity centroid. FINDINGS: Results revealed a statistically significant association between angulation and occurrence of thin-out (p < .001) and showed that the optimally angulated entry point resulted in decreased cortical breach across the nail insertion depth compared to the standard entry point. INTERPRETATION: Our findings suggested that the current straight nail design may require further modifications to optimise the nail trajectory within the medullary canal by decreasing the bone-nail geometric mismatch to potentially maximise its working length.

Effect of implant length variations on stress shielding in proximal humeral replacement after tumor excision under torsion: Finite element study.

The proximal humerus is the most common site of occurrence of primary bone tumors in the upper limb. Endoprosthetic replacement is deemed as the preferred reconstructive option following primary resection of bone tumors. However, it has been also associated with complications such as stress shielding and aseptic loosening compromising prosthetic survival. Our objective was to conduct a finite element (FE) study to investigate the effect of varying endoprosthesis length on bone stresses as well as to quantify the extent of stress shielding across the bone length (BL) in a humerus-prosthesis assembly for proximal humeral replacement after tumor excision thereby allowing us to identify the optimal implant length with best biomechanical performance. FE models of the intact humerus and humerus-prosthesis assemblies were established where they were loaded at the elbow joint under torsion with the glenohumeral joint fixed to represent twisting. After dividing the bone into individual slices consisting of 5% BL, the maximum cortical and cancellous principal, von Mises and shear bone stresses were calculated. To measure the level of stress shielding, the percentage stress change from the intact state was evaluated across each slice. Similar stress patterns were observed between the intact state and shorter endoprosthesis compared to the longer endoprostheses. Our findings illustrated the possibility of stress shielding occurring under torsional forces with its effect increasing with implant lengthening. To conclude, we believe that using a shorter prosthesis may substantially diminish the risk of potential implant failure due to stress shielding.

Relooking at double-bundle versus single-bundle anterior cruciate ligament reconstruction: A biomechanical model to evaluate which can confer better rotatory stability.

BACKGROUND: To treat anterior cruciate ligament (ACL) injuries, double-bundle ACL reconstruction has been proposed as a more anatomical approach relative to single-bundle reconstruction. However, controversy remains over which technique is superior in addressing knee instability, particularly rotational laxity. We hypothesize that double-bundle reconstruction better restores rotational knee laxity, while both methods are similar in restoring anterior knee laxity, to intact knee levels. METHODS: A controlled laboratory study. Eight cadaveric knees were tested accordingly: (1) static anterior laxity testing under 150 N-anterior tibial loading at 20°, 60° and 90° knee flexion using a material testing machine, followed by (2) dynamic simulated pivot-shift with knee-specific loading involving iliotibial band forces, valgus and internal rotation torques, while the knee was brought from extension to 90° flexion on a 6°-of-freedom custom-designed rig. Tibiofemoral kinematics were recorded using an electromagnetic tracking system for the ACL-intact, ACL-deficient, single-bundle and double-bundle ACL-reconstructed knee conditions. FINDINGS: Double-bundle reconstruction reduced internal rotation under pivot-shift to levels not significantly different from ACL-intact conditions (P > .173), unlike single-bundle that remained significantly higher at 10-40° flexion (P < .05). For anterior laxity, there was no significant difference between double-bundle, single-bundle, and ACL-intact conditions under static testing (P > .175) or pivot-shift (P = .219). The maximum extent of knee envelope laxity was significantly reduced for double-bundle relative to single-bundle, particularly for the rotatory component (P = .012). INTERPRETATION: Double-bundle was biomechanically superior to single-bundle in addressing envelope of rotation, while both techniques restored anterior knee laxity to ACL-intact levels.

Selective bundle versus complete anterior-cruciate ligament reconstruction: A systematic review and meta-analysis.

Purpose: Selective bundle reconstruction (SLB) refers to preservation of the intact bundle and reconstruction of the ruptured bundle in a partial tear while complete ACL reconstruction involves the removal of all remnant tissue and reconstruction of one or both bundles. As the evidence for SLB versus complete ACL reconstruction remains unclear, this study aimed to compare the two techniques. This study's hypothesis was that SLB reconstruction allows better function and stability compared to complete ACL reconstruction. Methods: A systematic search of PubMed, EMBASE, Scopus and Cochrane Library was conducted, identifying studies that compared SLB ('selective' group) versus complete ('complete' group) ACL reconstruction. Meta-analysis was conducted for post-operative functional scores, stability outcomes and complications as well as pre-operative to post-operative change. Results: Eleven studies were included in the meta-analysis, with 1107 patients and a pooled mean follow-up of 29.5 months. Post-operatively, the Selective group had significantly reduced anterior laxity, shown by a lower mean arthrometry side-to-side difference (p<0.01). Analysis of change results showed that the Selective group had a lower mean improvement in arthrometry side-to-side difference as well (p<0.01). No significant difference was shown for all other post-operative outcomes. Conclusion: This study provides valuable insight to the management of partial tears. It has demonstrated that the preservation of the intact bundle offers stability and function that is as good as complete reconstruction and that SLB is a potentially viable option in the management of partial tears. Level of evidence: Meta-analysis; Level of evidence, 4.

Bony Anatomy around the Watershed Line of the Distal Radius.

Background An important surgical landmark in the distal radius is the watershed line. The watershed line is a landmark for the positioning of volar locking plates (VLP) in the distal radius. Inconsistencies remain in the literature as to the presence and dimensions of landmarks in this compact area. We studied the detailed anatomy and dimensions of the distal radius with reference to bony anatomy around the watershed line, with special attention to the area between the pronator quadratus (PQ) and radial styloid. Materials and Methods The distal radius regions of 31 cadavers (23 right sided and 8 left sided) were dissected and studied. The heights at the junction of the scaphoid and lunate fossa, at the radial styloid, at the midpoint in between, and the widths of the PQ line, scaphoid, and lunate fossa were measured. The angle subtended by the pronator fossa and the radial styloid was also recorded. Results The mean heights at the junction of the scaphoid and lunate fossa, radial styloid, and midpoint in between were 5.1, 15.7, and 8.2 mm, respectively. The widths of the PQ line, scaphoid, and lunate fossa were 27, 19.4, and 10.6 mm, respectively. The mean angulation between the pronator fossa and the radial styloid was 128.9 degrees. Conclusion The area between the PQ and watershed line comprises a narrow area of bone which tapers to a point at its medial extent largely below the lunate fossa, thus it can hardly contain any implant proximal to the lunate fossa. The anterior orientation of this area and the concave anatomy of the articular surface mean careful screw direction is imperative to avoid inadvertent joint penetration. An angulation exists between the pronator fossa and the radial styloid, below the scaphoid fossa.

Hematopoietic Wnts Modulate Endochondral Ossification During Fracture Healing.

Wnt signaling plays a critical role in bone formation, homeostasis, and injury repair. Multiple cell types in bone have been proposed to produce the Wnts required for these processes. The specific role of Wnts produced from cells of hematopoietic origin has not been previously characterized. Here, we examined if hematopoietic Wnts play a role in physiological musculoskeletal development and in fracture healing. Wnt secretion from hematopoietic cells was blocked by genetic knockout of the essential Wnt modifying enzyme PORCN, achieved by crossing Vav-Cre transgenic mice with Porcnflox mice. Knockout mice were compared with their wild-type littermates for musculoskeletal development including bone quantity and quality at maturation. Fracture healing including callus quality and quantity was assessed in a diaphyseal fracture model using quantitative micro computer-assisted tomographic scans, histological analysis, as well as biomechanical torsional and 4-point bending stress tests. The hematopoietic Porcn knockout mice had normal musculoskeletal development, with normal bone quantity and quality on micro-CT scans of the vertebrae. They also had normal gross skeletal dimensions and normal bone strength. Hematopoietic Wnt depletion in the healing fracture resulted in fewer osteoclasts in the fracture callus, with a resultant delay in callus remodeling. All calluses eventually progressed to full maturation. Hematopoietic Wnts, while not essential, modulate osteoclast numbers during fracture healing. These osteoclasts participate in callus maturation and remodeling. This demonstrates the importance of diverse Wnt sources in bone repair.

Studies of the criteria for determining optimal location of medial patellofemoral ligament attachment sites.

Identifying appropriate attachment sites is important in the planning of medial patellofemoral ligament (MPFL) reconstruction. Two criteria are advanced to describe normal MPFL function, namely isometric criterion and desired pattern criterion. Subsequently, computational methods have applied these criteria to determine optimal attachment sites. So far, there is no study that compares the outcomes of these two criteria. For five subjects' 3D models of the patella and femur, three patellar sites and many femoral sites were identified as pairs of candidate attachment sites. For each patellar site, the criteria were applied to identify the matching femoral sites that satisfy them. The matching femoral site with the smallest length change was identified as the optimal femoral site. The desired pattern criterion finds fewer matching sites compared to the isometric criterion. In contrast, the isometric criterion can always find matching sites. The optimal femoral sites obtained vary significantly across different subjects. For most subjects, the optimal sites obtained using the isometric criterion are closer to known anatomical sites than those obtained using the desired pattern criterion. This study reaffirms that MPFL reconstruction is subject specific. The isometric criterion may be more reliable than the desired pattern criterion for determining optimal attachment sites. Graphical Abstract. Highlight of the paper. The location of the patella site significantly affects the location of the optimal femoral site. The isometric criterion option 1, with length at 0° regarded as MPFL's natural length, may be more reliable than other criteria or options for the planning of MPFL surgery because the optimal sites that it finds are closest to known anatomical sites.ᅟ.

No Difference in Outcome Between Articular-Sided and Bursal-Sided Tears: Comparative Study With Minimum 2-Year Follow-Up of Arthroscopic Repairs in 104 Patients in a Single-Surgeon Series.

PURPOSE: To evaluate and compare the functional outcomes after arthroscopic repair of bursal-sided versus articular-sided partial-thickness rotator cuff tears. METHODS: We conducted a retrospective analysis of patients who had undergone arthroscopic tear completion and subsequent repair of symptomatic partial-thickness rotator cuff tears in a single institution from 2010 to 2015. Range of motion (ROM) (forward flexion and abduction), the pain score as measured on the Numeric Pain Rating Scale, and outcome scores (Constant-Murley score, University of California, Los Angeles shoulder score, and Oxford Shoulder Score) were calculated preoperatively and at 1 year and 2 years postoperatively. The delta difference was calculated for each outcome parameter at the respective follow-up points as the difference from the preoperative baseline score. RESULTS: A total of 104 patients were included. All tears involved the supraspinatus tendon and did not exceed 2 cm. Of the patients, 65 had an articular-sided tear (AST) whereas 39 had a bursal-sided tear (BST). The mean age of the patients was 53.4 years in the AST group and 55.8 years in the BST group. The AST and BST groups did not differ preoperatively in terms of age, sex, and the measured outcome parameters. Postoperatively, the patients in both groups achieved statistically significant improvement in pain relief and functional outcomes at 2 years. No statistically significant difference was observed between the 2 groups in terms of the delta-difference outcomes in ROM in forward flexion (P = .781) or abduction (P = .348), pain score (P = .187), Constant-Murley score (P = .186), University of California, Los Angeles shoulder score (P = .911), and Oxford Shoulder Score (P = .186) at 2 years. CONCLUSIONS: Partial-thickness rotator cuff tears treated with arthroscopic tear completion and subsequent repair achieved good outcomes in terms of ROM, functional outcomes, and pain relief at 2 years. There was no difference in outcomes regardless of whether the location of the tear was articular sided or bursal sided. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Kinematic aligned femoral rotation leads to greater patella tilt but similar clinical outcomes when compared to traditional femoral component rotation in total knee arthroplasty. A propensity score matched study.

PURPOSE: External rotation of femoral component in total knee arthroplasty (TKA) with reference to the posterior condyles is recommended in mechanical alignment (MA) to ensure optimum patella tracking. In kinematic knee alignment (KA) technique, femoral component is more internally rotated as the femoral resection is based on flexion-extension axis. This study aims to investigate the clinical and radiological outcomes of the patellofemoral joint in patients who underwent TKA using KA versus mechanical alignment. METHODS: A review of prospectively collected registry data of 378 consecutive cruciate retaining primary TKAs (P.F.C.® Total Knee System, DePuy Synthes, Massachusetts, United States) was performed. Propensity scoring was performed matching patients who received KA TKA (n = 93) to MA TKA (n = 93). Oxford Knee Score (OKS), Knee Society Score (KSS), Short-Form 36 (SF-36), range of motion as well as radiographs assessing patella tilt were compared at 6 months and 2 years after surgery. All patients received the same implant and had their patella resurfaced. RESULTS: OKS, KSS, physical component of SF-36 and satisfaction rates were comparable at both 6 months and 2 years after surgery. There was moderate association between preoperative and postoperative patella tilt in KA TKA (Cramer's V = 0.260, p < 0.05). Postoperatively, KA group had a greater number of patients with lateral patella tilt compared to the mechanical group (12 [12.9%] vs 1 [1.1%], p < 0.001). Patella tilts, however, resolved two years after surgery. CONCLUSION: The relative internal rotation of the femoral component in KA TKA results in greater incidence of lateral patella tilt postoperatively. Nevertheless, patella tilt resolution was noted at 2 years. LEVEL OF EVIDENCE: Level III Evidence-Retrospective Cohort Study.

Biomechanical comparison of vertical suture techniques for repairing radial meniscus tear.

PURPOSE: The aim of this study was to (1) develop suture techniques in repairing radial meniscal tear; (2) to compare the biomechanical properties of the proposed repair techniques with the conventional double horizontal technique. METHODS: Thirty-six fresh-frozen porcine medial menisci were randomly assigned into four groups and a complete tear was made at the midline of each meniscus. The menisci were subsequently repaired using four different repair techniques: double vertical (DV), double vertical cross (DVX), hybrid composing one vertical and one horizontal stitch, and conventional double horizontal (DH) suture technique with suturing parallel to the tibia plateau. The conventional double horizontal group was the control. The repaired menisci were subjected to cyclic loading followed by the load to failure testing. Gap formation and strength were measured, stiffness was calculated, and mode of failure was recorded. RESULTS: Group differences in gap formation were not statistically significant at 100 cycles (p = .42), 300 cycles (p = .68), and 500 cycles (p = .70). A trend was found toward higher load to failure in DVX (276.8 N, p < .001), DV (241.5 N, p < .001), and Hybrid (237.6 N, p < .001) compared with DH (148.5 N). Stiffness was also higher in DVX (60.7 N/mm, p < .001), DV (55.3 N/mm, p < .01), and Hybrid (52.1 N/mm, p < .01), than DH group (30.5 N/mm). Tissue failure was the only failure mode observed in all specimens. CONCLUSION: Our two proposed vertical suture techniques, as well as the double vertical technique, had superior biomechanical properties than the conventional technique as demonstrated by higher stiffness and higher strength.

Effects of continuing use of aspirin on blood loss in patients who underwent unilateral total knee arthroplasty.

PURPOSE: Concerning the ongoing debate on the effects of continuing aspirin therapy on blood loss in knee arthroplasty, we conducted a retrospective investigation to test the hypothesis that continuation of aspirin prior total knee arthroplasty (TKA) will not cause more blood loss. METHODS: From a database of patients who underwent unilateral TKA between 2011 and 2016, we identified two groups: the aspirin group (patients continued aspirin during perioperative period) and the nonaspirin group (patients had no current or recent history of aspirin usage). We extracted and compared patient demographic information, comorbidity index, baseline serum hemoglobin (Hb), and creatinine level between the two groups. We also compared our primary outcomes, including the total blood loss, transfusion requirement, and length of hospitalization between the two groups. A multivariate logistic regression for analyzing the risk factors of requiring transfusion was performed. RESULTS: We found that apart from preoperative serum creatinine level, there was no difference in the baseline Hb level, perioperative change in Hb, total blood loss, or length of hospitalization between the two groups. The percentage of transfusion utilization was also comparable between the two groups. Our regression analysis shows that the risk of requiring transfusion after TKA is not significantly associated with patients taking aspirin therapy before operation. CONCLUSION: Patients who underwent TKA with continuation of low-dose aspirin did not result in more blood loss. Current blood loss management has provided sufficient reduction of blood loss to accommodate aspirin therapy perioperatively. We suggest that it is safe to continue aspirin prior to TKA.

Gap formation after single lateral row versus dual-row suture bridge cuff repair: An ovine biomechanical model.

BACKGROUND: The aim of this study is to compare two types of suture bridging constructs; a laterally based bridging single row (SR) construct and a classic dual row (DR) suture bridge construct. The hypothesis is that the DR construct will demonstrate superior biomechanical properties. METHODS: Six matched pairs of sheep infraspinatus tendon tears repaired with these two different types of suture bridging techniques were tested for gap formation, ultimate failure load and mode of failure. The specimens were pre-cycled for 10 cycles before they were subjected to a constant pre-load of 10N. The specimens were then subjected to cyclic loading at a speed of 8.33 mm/s. The test was stopped after every 500 cycles for a total of 3000 cycles. RESULTS: Mean gap formation after 3000 cycles was lower in the DR group (0.81 ± 0.2 mm versus 2.44 ± 0.27 mm; p = 0.002). Mean change in gap (with every 500 cycles) was also lesser for the DR group after 1500 cycles. DR repairs failed at a higher load (523.4 ± 80.4 N) compared to the SR repairs (452.3 ± 66.3 N) but this did not reach significance. All repairs failed with sutures pulling through the tendon during load to failure testing. CONCLUSIONS: Gap formation is significantly lower with a dual row suture bridge construct than a laterally based bridging single row construct. LEVEL OF EVIDENCE: Biomechanical study.

Functional outcome and quality of life in patients with hip fracture after total knee arthroplasty.

INTRODUCTION: Hip fractures are a cause of significant morbidity. While rare, ipsilateral hip fractures within 12 months after total knee arthroplasty (TKA) can negatively affect the functional outcome and the quality of life for patients who have had TKA. This aim of this study is to investigate (1) the incidence of hip fracture within 12 months after TKA and (2) the influence of hip fracture after TKA on functional outcome and quality of life in patients. METHODS: Between March 1999 and February 2012, 25 patients who sustained an ipsilateral hip fracture within 12 months after TKA were included in this study. A propensity score matching algorithm was used to select a 1:3 control group without hip fracture. All patients were assessed using the Oxford Knee Score (OKS), Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS), Physical Component Score (PCS) and Mental Component Score (MCS) of SF-36®. RESULTS: The incidence of hip fracture was 0.16% among male patients and 0.20% for female patients. At 24 months after TKA, the OKS was 36 ± 7 in the hip fracture group versus 41 ± 5 in the control group (p = 0.003). The KSFS was 50 ± 24 in the hip fracture group versus 68 ± 21 in the control group (p = 0.001), while the KSKS was 83 ± 12 and 87 ± 8, respectively (p = 0.166). The PCS was 37 ± 12 in the hip fracture group versus 47 ± 11 in the control group (p < 0.001), while the MCS was 55 ± 10 and 54 ± 11, respectively (p = 0.664). CONCLUSION: Although hip fracture during the rehabilitation period after TKA is uncommon, these patients have poorer functional outcome and quality of life. We recommend additional caution against hip fracture after TKA.

The Effect of Renal Transplantation in End-Stage Renal Failure Patients Undergoing Total Hip Replacement.

BACKGROUND: Patients with end-stage renal failure (ESRF) undergoing elective orthopedic surgery generally have higher postoperative morbidity and mortality compared to the general population. Studies on the outcome of ESRF patients undergoing total hip replacement (THR), especially those with a functioning renal transplant, are conflicting. We aim to evaluate the impact of renal transplantation on functional outcome and postoperative complications in patients with ESRF undergoing THR. MATERIALS AND METHODS: A total of 29 primary THRs were performed in 25 patients with ESRF between 1999 and 2013. There were 12 patients with 14 THRs who had a functioning renal transplant at the time of surgery (transplant group), and 13 patients with 15 THRs who were dialysis dependent with either no or failed prior transplant (nontransplant group). Functional outcome was evaluated with the Oxford Hip Score (OHS) and Western Ontario and McMaster Universities Osteoarthritis Index. Clinical records and followup radiographs were used to evaluate postoperative complications. RESULTS: There is lower mortality rate (P = 0.02) and lower overall complication rate in the transplant group compared to the nontransplant group (relative risk 0.60, 95% confidence interval 0.40-0.91, P = 0.008). The mean increase in OHS postoperatively was greater in the nontransplant group (nontransplant-24.7; transplant-18.7) and trended toward statistical significance (P = 0.06). CONCLUSION: ESRF patients who undergo THR experience improvements in functional outcome regardless of transplant status. There was no significant difference in postoperative functional outcomes between the two groups of patients, but patients with renal transplants are less likely to experience postoperative complications and have better survival.