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.

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.

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.

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.

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.

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.

Surgical Correction of Haglund's Triad Using a Central Tendon-Splitting Approach: A Retrospective Outcomes Study.

We evaluated the surgical outcomes of Haglund's triad using a central tendon-splitting approach, with Achilles tendon partial detachment and debridement, excision of the retrocalcaneal bursa, resection of Haglund's prominence, and reattachment of the Achilles tendon. The medical records of 22 patients (22 heels) who had undergone surgical correction of Haglund's triad from January 2010 to December 2015 were reviewed retrospectively. The visual analog scale pain score, American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale score, and 36-item Short-Form Health Survey physical and mental component scores were prospectively collected preoperatively, 6 months postoperatively, and at the last visit. The scores of a subjective question involving satisfaction were prospectively collected at the last visit. Possible risk factors were also evaluated. We reviewed the data from 12 females and 10 males, with the mean age of 59.2 ± 7.3 years and a mean follow-up duration of 15.1 ± 4.6 months. Significant improvement was found in the mean visual analog scale pain score, average American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scale score, and 36-item Short-Form Health Survey physical component scale score. The overall satisfaction rate was 77.3% (17 of 22). Postoperative complications included 2 cases of delayed wound healing and 1 case of sensation loss over the heel wound. No Achilles tendon rupture or wound infection developed. Gender and body mass index did not affect the surgical outcomes. The surgical technique we used for Haglund's triad provided effective pain relief, function improvement, and overall enhancement of patients' health condition. More research is required to further evaluate the outcomes of our surgical approach to treat Haglund's triad and the possible risk factors.

The accuracy of a hand-held navigation system in total knee arthroplasty.

INTRODUCTION: This study aims to evaluate the effectiveness of a new hand-held navigation system. The authors of this study hypothesize that this navigation system will improve overall lower limb alignment and implant placement without causing a delay in surgery. PATIENTS AND METHODS: Two hundred consecutive patients diagnosed with tricompartmental osteoarthritis and underwent total knee arthroplasty by a senior surgeon were included in this study. One hundred patients underwent TKA using the hand-held navigation system, while the other 100 patients underwent TKA using the conventional technique. The primary outcomes of this study were the overall alignment of the lower limb and the position of the components. This was determined radiologically using the: (1) Hip-Knee-Ankle angle (HKA) for lower limb alignment; (2) Coronal Femoral-Component angle (CFA); and (3) Coronal Tibia-Component angle (CTA) for component position. Normal alignment was taken as 180° ± 3° for the HKA and 90° ± 3° for both the CFA and CTA. RESULTS: For the CFA, the proportion of outliers was 7 and 17% in the hand-held navigation and conventional group, respectively (p = 0.030). For the HKA and CTA, there was no difference in the proportion of outliers between the two groups. The duration of surgery was 73 ± 9 min and 87 ± 15 min in the hand-held navigation and conventional group, respectively (p < 0.001). CONCLUSION: This hand-held navigation system is an effective intraoperative tool for reducing the proportion of outliers for femoral implant placement as well as the duration of surgery. The authors conclude that it can be considered for use to check femoral implant placement intra-operatively. LEVEL OF EVIDENCE: III.

Outcomes following total knee arthroplasty with CT-based patient-specific instrumentation.

PURPOSE: A 24-month prospective follow-up study was carried out to compare perioperative clinical outcomes, radiographic limb alignment, component positioning, as well as functional outcomes following total knee arthroplasty (TKA) between patient-specific instrumentation (PSI) and conventional instrumentation (CI). METHODS: Ninety consecutive patients, satisfying the inclusion and exclusion criteria, were scheduled to undergo TKA with either PSI or CI. A CT-based PSI was used in this study, and a senior surgeon performed all surgeries. Patients were clinically and functionally assessed preoperatively, 6 and 24 months post-operatively. Perioperative outcomes were also analysed, including operating time, haemoglobin loss, the need for blood transfusion, length of hospitalisation, and radiographic features. RESULTS: At 24-month follow-up, clinical and functional outcomes were comparable between the two groups. PSI performed no better than CI in restoring lower limb mechanical alignment or improving component positioning. There were no differences in operating time, haemoglobin loss, transfusion rate, or length of hospitalisation between PSI and CI. CONCLUSION: No significant clinical benefit could be demonstrated in using PSI over CI after 24 months, and routine use of PSI is not recommended in non-complicated TKA. LEVEL OF EVIDENCE: II.

Comparison of early outcome of Weil osteotomy and distal metatarsal mini-invasive osteotomy for lesser toe metatarsalgia.

PURPOSE: To compare the 6-month outcome of Weil osteotomy with distal metatarsal mini-invasive osteotomy (DMMO) in 33 patients with lesser toe metatarsalgia. METHODS: Records of 33 patients who underwent Weil osteotomy (n=20, 41 toes) or DMMO (n=13, 22 toes) for lesser toe metatarsalgia by a single surgeon were reviewed. 25 of them had a concurrent procedure on the 1st toe. Outcome at 6 months was assessed using the visual analogue score (VAS) for pain, American Orthopaedic Foot and Ankle Society (AOFAS) lesser toe metatarsophalangeal-interphalangeal (MTP-IP) score, and the RAND-36 score. RESULTS: The 2 groups were comparable in terms of age, gender, and preoperative MTP joint range of motion (ROM), VAS for pain, AOFAS lesser toe MTPIP score, and RAND-36 scores. At 6 months, the Weil osteotomy group had a higher RAND-36 (mental) score (92 vs. 78, p=0.026), and the DMMO group had a higher percentage of toes with greater MTP joint ROM (p=0.043). All patients achieved bone union within 6 months. Two patients in the DMMO group had prolonged oedema until 3 months post-surgery. CONCLUSION: DMMO is a safe and reliable alternative to Weil osteotomy for metatarsalgia and can preserve ROM of the MTP joints.

Preoperative haemoglobin cut-off values for the prediction of post-operative transfusion in total knee arthroplasty.

PURPOSE: The purpose of this study is to determine preoperative haemoglobin cut-off values that could accurately predict post-operative transfusion outcome in patients undergoing primary unilateral total knee arthroplasty (TKA). This will allow surgeons to provide selective preoperative type and screen to only patients at high risk of transfusion. METHODS: A total of 1457 patients diagnosed with osteoarthritis and underwent primary unilateral TKA between January 2012 and December 2014 were retrospectively reviewed. Logistic regression analyses were applied to identify factors that could predict transfusion outcome. RESULTS: A total of 37 patients (2.5 %) were transfused postoperatively. Univariate analysis revealed preoperative haemoglobin (p < 0.001), age (p < 0.001), preoperative haematocrit (p < 0.001), and preoperative creatinine (p < 0.001) to be significant predictors. In the multivariate analysis with patients dichotomised at 70 years of age, preoperative haemoglobin remained significant with adjusted odds ratio of 0.33. Receiver operating characteristic curve identified the preoperative haemoglobin cut-off values to be 12.4 g/dL (AUC = 0.86, sensitivity = 87.5 %, specificity = 77.2 %) and 12.1 g/dL (AUC = 0.85, sensitivity = 69.2 %, specificity = 87.1 %) for age above and below 70, respectively. CONCLUSIONS: The authors recommend preoperative haemoglobin cut-off values of 12.4 g/dL for age above 70 and 12.1 g/dL for age below 70 to be used to predict post-operative transfusion requirements in TKA. To maximise the utilisation of blood resources, the authors recommend that only patients with haemoglobin level below the cut-off should receive routine preoperative type and screen before TKA. LEVEL OF EVIDENCE: IV.

Intra-articular tranexamic acid wash during bilateral total knee arthroplasty.

PURPOSE: To compare the outcome after simultaneous bilateral total knee arthroplasty (TKA) with or without an intra-articular tranexamic acid (TXA) wash in terms of blood loss, haemoglobin change, and transfusion requirement. METHODS: 35 women and 10 men (mean age, 67.5 years) who underwent primary simultaneous bilateral TKA by a single senior surgeon were compared with 45 matched controls. In the TXA group, 1500 mg of TXA diluted in 100 ml of 0.9% sodium chloride was administered as a wash after cementing of implant and before closure of the retinaculum. At least 5 minutes of contact time was allowed before wound closure and tourniquet deflation. No drain was used. RESULTS: No patients had thromboembolic complication. Compared with controls, the TXA group had lower perioperative blood loss (920 vs. 657 ml, p=0.001), total blood loss (997 vs. 679 ml, p<0.001), blood transfusion rate (60% vs. 37.8%, p=0.035), percentage of patients requiring more than one blood unit (24.4% vs. 8.9%, p=0.048), and length of hospitalisation (6 vs. 4 days, p<0.001). Nonetheless, the 2 groups were comparable in blood units and volume transfused. CONCLUSION: An intra-articular TXA wash during simultaneous bilateral TXA reduced total blood loss and resulted in a difference of 22.2% in blood transfusion rate and a 2-day reduction in the length of hospital stay.

Drilling the near cortex with elongated figure-of-8 holes to reduce the stiffness of a locking compression plate construct.

PURPOSE: To compare the stiffness of locking compression plate (LCP) constructs with or without drilling the near cortex with elongated figure-of-8 holes. METHODS: 24 synthetic bones were sawn to create a 10-mm gap and were fixed with a 9-hole 4.5-mm narrow LCP. In 12 bones, the near cortex of the adjacent holes to the LCP holes was drilled to create elongated figure-of-8 holes before screw insertion. The stiffness of LCP constructs under axial loading or 4-point bending was assessed by (1) dynamic quasi-physiological testing for fatigue strength, (2) quasi-static testing for stiffness, and (3) testing for absolute strength to failure. RESULTS: None of the 24 constructs had subcatastrophic or catastrophic failure after 10 000 cycles of fatigue loading (p=1.000). The axial stiffness reduced by 16% from 613±62 to 517±44 N/mm (p=0.012) in the case group, whereas the bending stiffness was 16±1 Nm2 in both groups (p=1.000). The maximum axial load to catastrophic failure was 1596±84 N for the control group and 1627±48 N for the case group (p=0.486), whereas the maximum bending moment to catastrophic failure was 79±12 and 80±10 Nm, respectively (p=0.919). CONCLUSION: Drilling the near cortex with elongated figure-of-8 holes reduces the axial stiffness of the LCP construct, without compromising its bending stiffness or strength.

Prevalence of Metatarsus Adductus in Symptomatic Hallux Valgus and Its Influence on Functional Outcome.

BACKGROUND: Metatarsus adductus (MA) increases the risk of developing symptomatic hallux valgus (HV). This study aimed to determine the prevalence of MA in patients with symptomatic HV and to evaluate how it affected the functional outcome after scarf osteotomy. METHODS: Between January 2007 and June 2012, a total of 206 patients who underwent scarf osteotomy for symptomatic HV at a tertiary hospital were included. The metatarsus adductus angle (MAA) was determined using the Modified Sgarlato method, and these patients were categorized into 2 groups: MA (MAA > 20 degrees); and Control (MAA ≤ 20 degrees). The patients were prospectively followed for 2 years. RESULTS: The prevalence of MA was 33% (68/206) with a mean MAA of 24 ± 4 degrees (range = 20-39). There was a 21 ± 12 degrees and 18 ± 9 degrees improvement in hallux valgus angle for the MA and Control groups, respectively (P = .061), whereas there was a 6 ± 4 degrees and 6 ± 3 degrees improvement in intermetartarsal angle for the MA and Control groups, respectively (P = .475). The visual analog scale, AOFAS Hallux Metatarsophalangeal-Interphalangeal Scale, and Physical and Mental Component Scores were comparable between the 2 groups both preoperatively and at 2 years' follow-up (all P > .05). Two patients in the control group required revision surgery for recurrence symptomatic HV. CONCLUSION: The authors conclude that MA did not predispose the patient to poorer functional outcome after scarf osteotomy with the advent of good operative techniques. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Effect of Obesity on Outcome of Hallux Valgus Surgery.

BACKGROUND: Obesity is a global epidemic, but its effect on foot and ankle surgeries is not well defined. This study aimed to investigate the influence of obesity on functional outcome scores, incidence of postoperative surgical site infection (SSI), and repeat surgery after hallux valgus (HV) corrective surgery. METHODS: Between January 2007 and December 2011, 452 patients who underwent HV corrective surgery at a tertiary hospital were evaluated. They were categorized into 2 groups based on their body mass index (BMI): (1) BMI less than 30 kg/m(2) (control); (2) BMI 30 kg/m(2) or more (obese). The patients were prospectively followed for 2 years. RESULTS: Patients in the obese group were significantly older by 4 years (95% CI, 1-7 years) (P = .043). The preoperative American Orthopaedic Foot & Ankle Society Hallux Metatarsophalangeal-Interphalangeal (AOFAS Hallux MTP-IP) Scale and Physical Component Score were 6 points (95% CI, 1-11 points) and 3 points (95% CI, 1-6 points) poorer, respectively, in the obese group (P = .014 and P = .032, respectively). However, the Visual Analog Scale, AOFAS Hallux MTP-IP Scale, Physical Component Score, and Mental Component Score were comparable between the 2 groups at 6 months and 2 years of follow-up (all P > .05). Eleven patients (3%) in the control group and 1 patient in the obese group (2%) developed postoperative SSI (P = .777). Nine patients (2%) in the control group and 7 patients in the obese group (14%) required repeat surgery for complications (P < .001). CONCLUSION: The authors conclude that while it is important to warn obese patients of the significantly higher risk of repeat surgery, these patients should not be excluded from undergoing HV surgery. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

Effects of anesthetic technique on blood loss and complications after simultaneous bilateral total knee arthroplasty.

AIMS: Anesthetic technique affects perioperative outcomes, but less was known in simultaneous bilateral total knee arthroplasty (BTKA). A single center, retrospective analysis was carried out to prove the hypothesis that utilization of regional anesthesia would result in favorable perioperative outcomes. METHODS: Medical records of patients admitted for simultaneous BTKA between 2004 and 2013 were analyzed. Two groups, the general anesthesia (GA) and regional anesthesia (RA) group, were identified. Patient preoperative characteristics were compared. Perioperative outcomes measured included blood loss, transfusion requirement, length of hospitalization, operating time, and 30-day perioperative complications. RESULTS: A total of 513 patients were identified, 54.6% were performed under GA, and 45.4% under RA. Patient characteristics were similar between the two groups, except that patients operated under GA were younger than those under RA. RA was associated with significantly less perioperative blood loss (981 vs. 1075 mL, p = 0.017) and 30-day complications (6.4 vs. 13.2%, p = 0.016). Systemic and organ specific infections were particularly lower in the RA group (0.4 vs. 3.9%, p = 0.009). Transfusion requirement, length of hospitalization, and operating time were similar between the two groups. After correcting for covariates, RA offered a 92 mL (p = 0.023) reduction in blood loss and 49% less overall complications (p = 0.047), compared to GA. CONCLUSION: Patients who underwent simultaneous BTKA under RA had lesser blood loss and lower complication rate than GA. The impact of RA can be further exploited to improve perioperative outcomes of simultaneous BTKA in addition to various other interventions.

Radiological outcomes of pinless navigation in total knee arthroplasty: a randomized controlled trial.

PURPOSE: This study aimed to investigate the accuracy of pinless navigation (BrainLAB(®) VectorVision(®) Knee 2.5 Navigation System) as an intra-operative alignment guide in total knee arthroplasty (TKA). The authors hypothesized that pinless navigation would reduce the proportion of outliers in conventional TKA, without a significant increase in the duration of surgery. METHODS: Between 2011 and 2012, 100 patients scheduled for a unilateral primary TKA were randomized into two groups: pinless navigation and conventional surgery. All TKAs were performed with the surgical aim of achieving neutral coronal alignment with a 180° mechanical axis. The primary outcomes of this study were post-operative radiographic assessment of lower limb alignment using hip-knee-ankle angle (HKA) and components placement using coronal femoral-component angle (CFA) and coronal tibia-component angle (CTA). RESULTS: There was a smaller proportion of outliers for HKA, CFA and CTA at 10, 2 and 2 % respectively, in the pinless navigation group, compared to 32, 16 and 16 %, respectively, in the conventional group (p = 0.013, p = 0.032 and p = 0.032, respectively). The mean CFA was also more accurate at 90° in the pinless navigation group compared to 91° in the conventional group (p = 0.002). There was no difference in the duration of surgery between the two groups (n.s.). CONCLUSIONS: Pinless navigation improves lower limb alignment and components placement without a significant increase in the duration of surgery. The authors recommend the use of pinless navigation to verify the coronal alignments of conventional cutting blocks in TKA before the bone cuts are made. LEVEL OF EVIDENCE: I.

The radiological outcomes of patient-specific instrumentation versus conventional total knee arthroplasty.

PURPOSE: The aim of this study was to investigate the post-operative radiological outcomes of patient-specific instrumentation (PSI) surgery versus conventional total knee arthroplasty (TKA). METHODS: Sixty patients scheduled for a primary TKA were prospectively divided into PSI or conventional technique. Coronal and sagittal radiographic long limb films were taken post-operatively. The accepted values for normal alignment were 180° ± 3° for hip-knee-ankle angle; 90° ± 3° for coronal femoral component angle or coronal tibia component angle; 0° to 3° flexion for sagittal femoral component angle and 0° to 7° posterior slope for sagittal tibia component angle. RESULTS: For hip-knee-ankle angle, there were 21 % more outliers in the PSI group compared to the conventional group (p = 0.045). Most of these outliers had valgus deformity in the PSI group and varus deformity in the conventional group (p = 0.045). For implant placement, there was no difference in the proportion of outliers between the two groups. There was also no difference in the duration of surgery. CONCLUSIONS: This study showed that PSI surgery is associated with a larger proportion of outliers for lower limb alignment. PSI surgery as an alternative to conventional TKA is not advisable. LEVEL OF EVIDENCE: II.