Mid-term results and survival rates following a single-design rotating hinge knee arthroplasty in non-tumor conditions in a Pakistani population

( Nouman Memon ),( Faizan Iqbal ),( Syed Shahid Noor ),( Kazim Rahim Najjad ),( Muhammad Farhan Sozera ),( Arsalan Abro ),( Noman Khan ) 대한슬관절학회 2021 대한슬관절학회지 Vol.33 No.-

Background: Information regarding the use of hinged implants in non-oncological conditions is limited in our region due to a lack of adequate data collection and follow-up. The purpose of this study is to evaluate mid-term results and risk factors affecting the survivorship of third-generation rotating hinge knee (RHK) patients in nononcological conditions. Methods: We retrospectively reviewed 41 single, third-generation, rotating hinge prostheses in three complex primary knee procedures and 38 revision knee surgeries in between 2007 to 2014. Implant survival was assessed using the Kaplan-Meier method. Factors influencing implant survival were identified using the log-rank test. During the study period, clinical results along with complications were assessed. Clinical outcomes were assessed by using the Knee Society Score (KSS). Results: RHK arthroplasty was used in 41 patients. Out of 41 patients, a RHK was used in three patients with a complex primary deformed knee whereas in 38 patients, a RHK was used in revision arthroplasty surgery. The cumulative implant survival rate with re-revision due to any cause was found to be 87.8% (95% CI 69.2-90.1) at 5-7 years. Prosthetic joint infection, peri-prosthetic fracture and extensor mechanism complications were the commonest mode of failure. The P value was found to be significant when comparing KSS pre-operatively and post-operatively. Conclusion: The cumulative implant survival rate was found to be 87.8%. Prosthetic joint infection was the commonest mode of failure in patients who underwent third-generation RHK surgery for variable indications. Being a patient with a high Charlson comorbidity index is the main risk factor associated with failure of the rotating hinge implant.

The Unusual Cause of Prosthetic Joint Infection: Outcomes of Nontuberculous Mycobacteria Treatment Following Primary Total Knee Arthroplasty

Faizan Iqbal,Syed Shahid Noor,Kazim Rahim Najjad,Sadia Ishaque,Nouman Memon,Sheh Zano 대한정형외과학회 2022 Clinics in Orthopedic Surgery Vol.14 No.4

Background: Nontuberculous mycobacterium (NTM) is a rare cause of prosthetic joint infection (PJI) following primary total knee arthroplasty (TKA). NTM causes a variety of infections, mainly divided into pulmonary and extrapulmonary infections. In Pakistan, there was a 7.7-fold increase in NTM infections from 21 cases in 2012 to 163 cases in 2018. An earlier study evaluating the distribution of NTM species across Pakistan suggested geographical variation across different regions, every area having its own distribution spectrum. There are no data available especially in developing countries such as Pakistan regarding PJI due to NTM following primary TKA. The purpose of our study was to determine treatment outcomes of two-stage revision surgery following NTM infection. Methods: This is a retrospective study. Patients who underwent TKA between June 2008 and December 2018 were included in the study. NTM was defined as the presence of traditional criteria for diagnosing PJI plus growth of NTM cultured from a joint aspirate or deep periprosthetic tissue specimen using Löwenstein-Jensen medium and Mycobacteria Growth Indicator Tube medium. All patients were female with a mean age of 62.8 ± 7.9 years. The mean body mass index was 25.6 ± 2.8 kg/m². Treatment outcomes were categorized into favorable and unfavorable. Results: We found rapid-growing mycobacterium in 6 patients whereas slow-growing mycobacterium was found in 2 patients only. Generally, clarithromycin was the standard antibiotic used in all cases of NTM infections. All patients underwent revision surgery. Conclusions: Meticulous surgical debridement and prolonged antibiotic treatment course were the only hope of cure to combat the unusual cause of PJI following primary TKA.

Economic Burden of Periprosthetic Joint Infection Following Primary Total Knee Replacement in a Developing Country

Faizan Iqbal,Bilal Shafiq,Syed Shahid Noor,Zulfiqar Ali,Nouman Memon,Naveed Memon 대한정형외과학회 2020 Clinics in Orthopedic Surgery Vol.12 No.4

Background: Periprosthetic joint infection is one of the devastating complications after primary total knee arthroplasty, which increases the financial burden on patients and affects their quality of life as well. The financial burden of periprosthetic joint infection after joint replacement in developed countries is well known. There is a need to evaluate the economic burden in developing countries such as Pakistan. Methods: This is a single-center, retrospective, case-control study conducted at the Department of Orthopedic Surgery, Liaquat National Hospital Karachi. Cases of primary total knee arthroplasty performed during this study were divided into 2 groups: uneventful primary total knee arthroplasty and periprosthetic joint infection treated with 2-stage revision. To calculate the final cost, we divided the total hospital cost into the hospital stay cost and operating room cost. Results: During study period, 32 patients were diagnosed with periprosthetic joint infection. The total cost of revision surgery for periprosthetic joint infection considering 2 hospitalizations was 1,780,222 ± 313,686 Pakistani rupee (PKR). The total cost of uneventful arthroplasty was 390,172 ± 51,460 PKR. We observed significant difference with respect to economic details between the 2 groups. Conclusions: Management of periprosthetic joint infection was 4.5 times more expensive than uneventful primary total knee arthroplasty. Measures should be undertaken to reduce the prevalence of periprosthetic joint infection, thereby reducing patients’ economic burden.

Experimental and Numerical Investigation of Stress Concentration at Rib-to-Crossbeam Joint

Heng Fang,Nouman Iqbal,Gilles Van Staen,Hans De Backer 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.1

In orthotropic steel decks (OSDs), the rib-to-crossbeam joint is the most vulnerable detail that has not been drawn enough attention. The failure mode of cracks initiate from the lower weld end on rib wall is governing its fatigue performance. However, relevant detail categories are still missing in prevailing codes. This paper mainly focuses on the stress concentrations at the rib-to-crossbeam joint induced by rib distortions. A series of static load tests were fi rst performed on a full-scale OSD specimen with diff erent weld length between the ribs and the crossbeam. Then, corresponding numerical simulations were fi nished. Several possibilities that may cause the diff erences between the measurements and the calculations are investigated. At last, fatigue assessments based on infl uence lines of structural hot spot stress (SHSS) are completed. Research results reveal that the measurement results of reference points for SHSS method would be very sensitive to the exact location of strain gauges. Due to the manual welding, the deviation of strain gauge positions induced by the irregular weld shape is thought to be the main reason that causes the diff erences between measurements and calculations. Raising the location of cope hole terminations would decrease distortional stresses. However, the infl uence of this parameter on fatigue lives is rather small. The fatigue lives of points along the lower weld toe are very close. Hence, the point at the middle plane of crossbeam could be used as the reference point for fatigue assessments. Meanwhile, the center between ribs could be used as the reference transverse load position for fatigue assessments of this joint.

Impact of Tibial Tubercle Osteotomy on Final Outcome in Revision Total Knee Arthroplasty: Our Experience and Technique in Pakistan

Abdul Rafay Qazi,Faizan Iqbal,Syed Shahid Noor,Nasir Ahmed,Akram Ali Uddin,Nouman Memon,Naveed Memon 대한정형외과학회 2021 Clinics in Orthopedic Surgery Vol.13 No.1

Background: Due to extensive fibrosis during revision surgery, adequate exposure is essential and it can be achieved with several extensile approach options, such as tibial tubercle osteotomy. Information regarding surgical exposure during revision arthroplasty is limited in developing countries, such as Pakistan, due to the lack of adequate data collection and follow-up. Therefore, the purpose of this study was to evaluate the impact of tibial tubercle osteotomy on final outcome of revision total knee arthroplasty (TKA). Methods: A total of 231 revision TKAs were performed between January 2008 and December 2017. Twenty-nine patients underwent tibial tubercle osteotomy for adequate exposure during revision surgery. Of these, 27 patients with complete follow-up were included in our study. Factors examined include age at the time of revision surgery, gender, comorbidities, arthroplasty site (right or left), body mass index (BMI), and primary indications for the tibial tubercle osteotomy during revision TKA. Functional outcome was measured by using Knee Society score (KSS) at 3 months and the final follow-up. All statistical analysis was done using SPSS version 20.0 with a p-value < 0.05 considered significant. Results: Out of 27 patients, 6 patients (22.2%) were men and 21 patients (77.7%) were women. Right knee revision arthroplasty was performed in 15 patients (55.5%), left knee revision arthroplasty was performed in 12 patients (44.4%), and bilateral revision surgery was performed in only 1 patient (3.7%). The mean BMI was 29.2 kg/m2. We used a constrained condylar knee in 20 patients (74%), a rotating hinge knee in 5 patients (18.5%), and mobile bearing tray plus metaphyseal sleeves in 2 patients (7.4%). The KSS was 52.21 ± 4.05 preoperatively, and 79.42 ± 2.2 and 80.12 ± 1.33 at 3 months and 12 months, respectively. Radiological union was achieved in all patients at 3 months. Of 27 patients, only 1 patient (3.7%) had proximal migration of the osteotomy site at 6 months: the patient was asymptomatic and union was also achieved and, therefore, no surgical intervention was performed. Conclusions: Tibial tubercle osteotomy during revision TKA can be a safe and reliable technique with superior outcomes and minimal complication rates.