Ming Han Lincoln Liow

Robot-Assisted Total Knee Arthroplasty Accurately Restores the Joint Line and Mechanical Axis. A Prospective Randomised Study

Robot-assisted Total Knee Arthroplasty (TKA) improves the accuracy and precision of component implantation and mechanical axis (MA) alignment. Joint-line restoration in robot-assisted TKA is not widely described and joint-line deviation of>5mm results in mid-flexion instability and poor outcomes. We prospectively randomised 60 patients into two groups: 31 patients (robot-assisted), 29 patients (conventional). No MA outliers (>±3° from neutral) or notching was noted in the robot-assisted group as compared with 19.4% (P=0.049) and 10.3% (P=0.238) respectively in the conventional group. The robot-assisted group had 3.23% joint-line outliers (>5mm) as compared to 20.6% in the conventional group (P=0.049). Robot-assisted TKA produces similar short-term clinical outcomes when compared to conventional methods with reduction of MA alignment and joint-line deviation outliers.

Accelerometer-Based Navigation Is as Accurate as Optical Computer Navigation in Restoring the Joint Line and Mechanical Axis After Total Knee Arthroplasty: A Prospective Matched Study.

The Zimmer iASSIST system is a novel accelerometer-based navigation system for TKA. 76 patients (76 knees) were prospectively matched for age, BMI, gender, diagnosis, and pre-operative scores, and underwent TKA using the iASSIST (n=38) or optical CAS (n=38). There were no significant differences in clinical outcomes or satisfaction rates at six months post-operatively (P>0.05). Mechanical axis was 1.8±1.3° in the iASSIST cohort versus 2.1±1.6° in the CAS cohort (P=0.543). There were no significant differences in number of outliers for mechanical axis (P=1.000), coronal femoral-component angle (P=0.693), coronal tibial-component angle (P=0.204) or joint line deviation (P=1.000). The duration of surgery was significantly longer in the CAS group (P<0.001), while the added cost of accelerometer-based navigation was approximately

Four-Year Follow Up Outcome Study of Patellofemoral Arthroplasty at a Single Institution

1000 per operation.

Critical Shoulder Angle and Acromial Index Do Not Influence 24-Month Functional Outcome After Arthroscopic Rotator Cuff Repair

Patellofemoral arthroplasty (PFA) is an option for younger patients with isolated patellofemoral arthritis. Older PFAs had high failure rates due to poor design. This retrospective study reports the outcomes of PFA at a single institution using a second-generation implant. Fifty-one patients (51 knees) with isolated patellofemoral arthritis underwent PFA. Mean follow-up was 4.1 years (range, 2.2-6.1). Mean Knee Society objective and function scores, Oxford Knee score, Melbourne Knee score and Physical Component Score improved significantly. 76% had their expectations fulfilled and 76% experienced good satisfaction. Mean Insall-Salvati and Caton-Deschamps ratios increased significantly. Two wound infections (3.92%) were encountered. Survivorship was 92.2% with four revisions, two due to progression of arthritis, one due to patella maltracking, and one due to anterior knee pain.

THINK surgical TSolution-One® (Robodoc) total knee arthroplasty

Background: Recent studies have shown a correlation between scapular geometry and the development of atraumatic rotator cuff tears. However, a paucity of literature is available on the effects of critical shoulder angle (CSA) and acromial index (AI) on functional outcomes after arthroscopic rotator cuff repair. Hypothesis/Purpose: The purpose was to investigate the influence of CSA and AI on 24-month functional outcomes after arthroscopic rotator cuff repair. The hypothesis was that a larger CSA or AI would result in poorer postoperative outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: The study included 147 patients who underwent arthroscopic double-row rotator cuff repair for radiologically documented full-thickness supraspinatus tears. An independent reviewer measured the CSA and AI on preoperative radiographs. These patients were prospectively enrolled and were evaluated preoperatively as well as at 3, 6, 12, and 24 months postoperatively. Functional outcome was assessed with the Constant Shoulder Score (CSS), Oxford Shoulder Score (OSS), and University of California at Los Angeles (UCLA) Shoulder Rating Scale. The patients were first divided based on CSA: (1) ≤35° (control CSA) and (2) >35° (increased CSA); and then based on AI: (1) ≤0.7 and (2) >0.7. The Student unpaired t test, Pearson chi-square test, and Pearson correlation were performed to examine the influence of CSA and AI on postoperative functional outcome scores. Results: At 6 months of follow-up, the CSS, OSS, and UCLA Shoulder Rating Scale were 10 ± 1, 4 ± 2, and 3 ± 1 points poorer in the increased CSA group compared with the control CSA group (P = .005, P = .030, and P = .035, respectively). These scores were not significantly different between both AI groups. By 24 months of follow-up, all outcome scores were comparable between both CSA groups as well as between both AI groups. No significant correlation was found between either CSA or AI when compared with CSS, OSS, or UCLA Shoulder Rating Scale at 24 months of follow-up. Conclusion: CSA and AI do not appear to influence 24-month functional outcomes postoperatively and hence are not contraindications to arthroscopic rotator cuff repair.

The effect of gender in hallux valgus surgery. A propensity score matched study

THINK Surgical TSolution-One® is an active-autonomous, image-based, robotic milling system which enables the surgeon to attain a consistently accurate implant component positioning. The TSolution-One® system is capable of achieving this through an image-based preoperative planning system which allows the surgeon to create, view and analyse the surgical outcome in 3D. The accuracy and precision of component positioning have been attributed to the following factors: customized distal femoral resection, accurate determination of the femoral rotational alignment, minimization of errors and maintenance of bone temperature with robotic milling. Despite all these advantages, there is still a paucity of long-term, high-quality data that demonstrates the efficacy of robotic-assisted total knee arthroplasty (TKA). Questions regarding radiation risks, prolonged surgical duration and cost-effectiveness remain unanswered. This paper aims to describe: (1) TSolution-One® surgical technique; (2) limitations and complications; (3) clinical and radiological outcomes.

Outcome following total knee arthroplasty in obese versus non-obese Asian patients.

BACKGROUND Males and females who undergo hallux valgus (HV) surgery have different expectations. METHODS Data from 439 patients, with 26 males, were prospectively collected between 2007-2015. Propensity score matching (PSM) of one male to two females was performed using logistic regression of six variables to minimize selection bias. Hallux visual analogue scale (VAS) scores, AOFAS scores, SF-36, satisfaction and expectation scores were analysed at two years. RESULTS There were no significant differences in patient demographics after PSM. At two years, males and females attained similar VAS and AOFAS scores but males had significantly lower SF-36 general health score (males 68.7, females 79.3). 26.9% of males and 21.2% of females were not satisfied after surgery. Higher proportion of males did not have their expectations fulfilled (males 19.2%, females 5.8%) although this was not statistically significant. CONCLUSIONS Both genders attain similar outcome at two years. There is a trend towards lower expectation fulfilment in males after surgery.

Obesity and the absence of trochlear dysplasia increase the risk of revision in patellofemoral arthroplasty

Purpose. To compare the outcome following total knee arthroplasty (TKA) in obese and non-obese Asian patients. Methods. 27 obese patients were compared with 27 non-obese controls matched for age, gender, diagnosis (osteoarthritis), prosthesis, preoperative Knee Society knee and function scores, preoperative Oxford Knee Score, and follow-up duration. All TKAs were performed by a single surgeon. Patients were assessed at 6 months and 2 years for the range of motion, Knee Society knee and function scores, Oxford Knee Score, and Short Form-36 Health Survey (SF-36). Results. The obese and non-obese groups did not differ significantly in pre- and post-operative variables: range of motion, Knee Society knee and function scores, Oxford Knee Score, and SF-36 score. Using revision as an end-point, implant survival was 100%. There were no intra- or post-operative complications in either group. Conclusion. Obese and non-obese Asian patients achieved a comparable outcome following TKA.