American Knee Society Research Articles

Septic Revision Total Knee Arthroplasty: Treatment of Metaphyseal Bone Defects Using Metaphyseal Sleeves

BackgroundBone loss is a severe problem in septic revision total knee arthroplasty (RTKA). The use of porous coated metaphyseal sleeves is a promising treatment option for metaphyseal bone defects. The currently published midterm results remain limited and no study has been focused exclusively on septic cases. Our aim was to determine the implant survivorship (with special focus on osseointegration) and the clinical and radiological midterm outcome of metaphyseal sleeve fixation in septic RTKA surgery (minimum follow-up of 2 years). MethodsWe performed a clinical and radiographic examination of 56 patients with a history of prosthetic joint infection who underwent 2-stage RTKA with the use of porous coated metaphyseal sleeves. These examinations included evaluation of the American Knee Society Score, the Western Ontario and McMaster Universities Osteoarthritis Index, the Short Form (SF-36) Health survey as well as radiographic measurement to determine whether successful osseointegration had been achieved. ResultsNine patients (16%) had to be re-revised at the time of follow-up (mean, 5.3 years; range, 2-11.2), all due to reinfection. We did not encounter any cases of aseptic loosening. The mean range of motion (92°, SD ± 21°), subjective satisfaction score (7, SD ± 2), American Knee Society Score (76, SD ± 19), Western Ontario and McMaster Universities Osteoarthritis Index (70, SD ± 20), SF-36 mental component summary (55, SD ± 14), and SF-36 physical component summary (35, SD ± 9) have shown satisfying results. ConclusionMetaphyseal sleeves have shown very promising midterm results regarding clinical scores, osseointegration, and aseptic loosening. Our results are the first analyzing exclusively septic indications and indicate that they are a reliable fixation option in all bone defect types in septic RTKA patients.

Revision total knee arthroplasty: hybrid vs standard cemented fixation

IntroductionModular systems with stems are necessary for the stability of revision total knee arthroplasty (rTKA), but controversy remains as to the best fixation method: cemented or hybrid (noncemented stem). The aim of this study was to assess the clinical, X-ray, life-quality and survival results obtained with each fixation method.Materials and methodsDuring the period 2000–2013, rTKA was performed on 67 patients (29 cemented arthroplasty and 38 hybrid fixation). The average follow-up was 7 years (range 2–15). All patients were evaluated clinically and radiographically using the American Knee Society Score (AKSS), the Western Ontario and McMaster Universities Arthritis Index (WOMAC), and the Short Form Health Survey (SF-36). A survival study was performed via Kaplan–Meier analysis.ResultsThere were no differences between the cemented and hybrid fixation groups in the preoperative and postoperative AKSS clinical evaluation indices and the SF-36 health index. However, the WOMAC assessment scale did reveal statistically significant differences between the groups, with a global classification of 64.9 points weighted at 100 (SD 16.8) for cemented fixation versus 78.9 (SD 9.0) for hybrid fixation (p = 0.001). The corresponding values for stiffness were 61.6 (SD 12.9) and 80.5 (SD 14.7) (p = 0.001), and those for function were 61.3 (SD 19.4) and 78.1 (SD 10.5) (p = 0.001). No significant differences between the groups were recorded with respect to the pain score (p = 0.4) or the results of the Kaplan–Meier survival analysis.ConclusionAlthough the results were similar for the two groups, hybrid fixation tended to produce better results than cemented fixation. In view of the risk of further loosening, we prefer the more conservative approach, i.e. hybrid fixation.Level evidenceLevel III.

Does pre-operative anxiety and/or depression affect patient outcome after primary knee replacement arthroplasty?

BackgroundChronic pain is associated with psychological distress, most commonly manifested as anxiety and/or depression. MethodsIn order to investigate the effect of such distress on outcome from knee arthroplasty, we prospectively investigated the anxiety and depression levels of 104 patients undergoing a total of 107 primary knee arthroplasty procedures and the outcomes they achieved pre-operatively and at six weeks, one year and seven years post-operatively. The Hospital Anxiety and Depression Scale was used to record psychological status. Oxford Knee Score and American Knee Society Score were used to record functional outcomes. ResultsForty-four percent (47/107) of the patients had an abnormal pre-operative anxiety and/or depression score. Mean anxiety and depression scores improved at six weeks and one year of follow-up, but then deteriorated slightly at seven years, albeit not back to baseline. Knee scores showed similar patterns over time. Regardless of pre-operative psychological status, mean AKSS Knee scores improved at six weeks and further improved at one year post-op. They then showed slight deterioration at seven years, but remained significantly better than pre-op. ConclusionsPsychological distress is common in our patients pre-operatively. Improvements in knee pain and function as a result of surgery correlate well with lower levels of psychological distress post-operatively. Knee replacement surgery positively influences all of the outcome measures studied rather than recovery being negatively influenced by pre-operative states. Knee replacement arthroplasty is not contra-indicated by pre-operative psychological distress. Successful knee replacement improves knee pain and function, as well as symptoms of anxiety and depression. These improvements persist for many years after the surgery.

Causes and treatment outcomes of revision surgery after open reduction and internal fixation of tibial plateau fractures.

Treatment of a tibial plateau fracture (TPF) remains controversial and is generally challenging. Many authors report good results after conventional open reduction and internal fixation in TPF, but complications still occur. This study analyzed causes and outcomes of revision surgery for TPF. The usefulness of a flow chart for revision surgery in TPF was also evaluated. We reviewed all patients who underwent more than two operations for a TPF between 2008 and 2015. Finally, 24 cases were selected and retrospectively investigated. The medial tibial plateau angle and proximal posterior tibial angle were radiologically evaluated. The American Knee Society Score (AKSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), range of motion (ROM), and bone union time were investigated after surgery. Revision surgery for infection was performed in eight cases, for nonunion in six cases, for posttraumatic arthritis (with total knee arthroplasty) in six cases, and for other reasons in four cases. The mean clinical AKSS at final follow-up was 87.3 ± 5.3 (range, 75-95), the functional AKSS was 81.9 ± 5.5 (range, 70-90), the WOMAC score was 9.9 ± 3.1 (range, 5-16), the flexion ROM was 119.8 ± 16.5° (range, 100-150°), and the extension ROM was 2.5 ± 3.3° (range, 0-10°). Although complications cannot be avoided in some cases, good clinical outcomes are possible when patients are divided according to the presence or absence of infection, with selection of appropriate revision surgery as shown in the flow chart. If an infection is present, treatment should be based on the presence or absence of bone union. If there is no infection, treatment should be based on the presence or absence of nonunion, post-traumatic arthritis, malunion, or immediate post-operative malreduction.

Does the Surgeon-reported Outcome Correlate with Patient-reported Outcome after Total Knee Arthroplasty? A Cohort Study.

Background:Total knee arthroplasty (TKA) has been proved to be a successful and cost-effective treatment for improving pain and function in patients with knee arthritis. Total knee arthroplasty (TKA) is one of the most common orthopaedic surgeries performed worldwide and advancement in surgical techniques and prosthetic designs have improved the patient outcomes. However, concerns and priorities of patients and surgeons relating to joint replacement may differ.Materials and Methods:306 TKAs in 223 patients were evaluated for functional outcome using surgeon reported American Knee Society Knee Score (KS)/Functional Score (FS) and patient-reported Oxford Knee Score (OKS). We have also assessed the correlation between FS and OKS at midterm follow up.Results:The mean preoperative KS, FS, and OKS in 223 patients were 42.76, 42.4, and 38.84 and the midterm mean KS, FS, and OKS were 84.29, 73.40, and 30.26, respectively. There was a statistically significant improvement in the KS, FS, and OKS at midterm follow up in Category A (CAT A) (bilateral TKA or unilateral with asymptomatic contralateral knee), CAT B (unilateral TKA with symptomatic other knee) and CAT C (inflammatory arthritis). Overall, the correlation between the midterm FS and OKS was fair. However, in CAT A and CAT B, there was no significant correlation between FS and OKS, but CAT C had a strong correlation. There was a statistically significant improvement in the KS, FS, and OKS when midterm follow up scores were compared with preoperative scores. However, no significant correlation between the American knee society FS and OKS in osteoarthritic patients at midterm follow up signifies acceptable outcome may vary between patients and physicians.Conclusion:All patients should be counseled preoperatively to assess their expectations and sensitize them to information regarding the expected functional outcome following TKA in their cultural context.

Navigated versus conventional total knee arthroplasty: A prospective study at three years follow-up

ObjectiveComputer-assisted surgery application in total knee arthroplasty (TKA) has shown more accurate implant alignment compared with conventional instrumentation and is associated with more homogeneous alignment results. Although longer implant survival and superior clinical outcomes should be expected from navigated TKA, currently available evidence does not support this hypothesis. The aim of this study was to compare navigated TKA with conventional TKA regarding clinical and radiological outcomes after a 3-year follow-up under the hypothesis that navigated TKA would provide better outcomes than conventional TKA. Material and methodIn a prospective multicentre study, 119 patients underwent navigated TKA and 80 patients received conventional instrumentation. Patients were evaluated at the baseline and at postoperative months 3, 12, 24, and 36. Analysis included the American Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form-12 (SF12) Health Survey, and radiographic assessment. ResultsAll clinical scores improved significantly for all patients during the follow-up but were significantly better in the navigation group.The percentage of patients showing a mechanical axis between 3° of varus and 3° of valgus was significantly higher in the ATR group (93%) than in the conventional TKA group (71%) (p<.01). ConclusionsThe use of computer-assisted surgery in TKA provides more accurate mechanical alignment and superior short-term functional outcomes compared to conventional TKA.

Early Results of Oxford Mobile Bearing Medial Unicompartmental Knee Replacement (UKR) with the Microplasty Instrumentation: An Indian Experience.

Oxford medial unicompartmental knee replacement (UKR) is indicated in patients with anteromedial osteoarthritis (AMOA) of the knee. Microplasty (MP) instrumentation was introduced in 2012 as an improvement over phase 3 instrumentation. Advantages of this instrumentation include conservative tibial cut, decreased tibial re-cut rate and improved component alignment. We report the results of UKR with the new instrumentation in a consecutive series with a minimum follow-up of 2 years. A prospective study of 115 cemented medial Oxford UKRs implanted in 89 patients was done. Post-operative alignment of the tibial and femoral components was analysed. Patient reported outcome measures were recorded using Oxford Knee Score (OKS) and the American Knee Society Score (KSS). Tegner Activity Scale (TAS) was used to record the activity level. 115 consecutive medial Oxford UKRs were studied. All patients were followed up annually in this prospective ethically approved study. The mean follow-up was 36 months and the minimum follow-up was 25 months. No patient died and none were lost to follow-up. At the final follow-up, the average OKS of the cohort was 39.5 (SD: 5.7). 91.2 % of the patients had good or excellent OKS with only 3.5 % reporting poor OKS. The overall limb alignment was 4.80 varus (0 - 140 varus). Tibia was recut in 5.2 % of cases. Median bearing size was 3 (range: 3 to 6). There was one case of bearing dislocation and one case of aseptic tibial loosening. This is the first study to report results of MP instrumentation at a minimum follow-up of 2 years. Our study indicates that the new instrumentation results in reliable and accurate implantation of femoral and tibial components in majority of the cases, with a decrease in number of alignment outliers, and also a reduced rate of bearing dislocation.

Effect of Increased Coronal Inclination of the Tibial Plateau After Opening-Wedge High Tibial Osteotomy

To assess whether the increased inclination of the tibial plateau on the coronal view after opening-wedge high tibial osteotomy affects radiographic coronal alignment, clinical outcomes, and cartilage findings. After adjustment for the preoperative medial proximal tibial angle (MPTA), patients who underwent opening-wedge high tibial osteotomy were retrospectively divided into those with postoperative MPTA values of 95° or less (normal group) and greater than 95° (increased group), with each group containing 43 knees. The 2 groups were compared regarding their arthroscopic cartilage findings at 1year postoperatively and radiographic coronal alignment and clinical outcomes at 2years postoperatively. Cartilage regeneration in the medial condyles and cartilage deterioration in the lateral condyles were evaluated at the time of second-look arthroscopy. Clinical outcomes were evaluated by the American Knee Society knee and function scores, Lysholm knee scoring scale, and Knee Injury and Osteoarthritis Outcome Score (KOOS). The postoperative anatomic femorotibial angle in the increased group was lower than that in the normal group (P < .001), and the amount of overcorrection in the increased group was higher than that in the normal group (P < .001). The postoperative joint line obliquity in the increased group was higher than that in the normal group (P < .001). Cartilage regeneration in the medial condyles and deterioration in the lateral condyles did not differ significantly on the femoral and tibial sides between the groups. The postoperative American Knee Society knee score and KOOS sports and recreational function subscale score in the normal group were higher than those in the increased group (both P < .001). There were no significant differences in the changes in the appearance of the articular surfaces between the 2 groups at 1year postoperatively. Patients with a postoperative MPTA greater than 95° had more valgus alignment and higher joint line obliquity and had a lower KOOS sports and recreational function subscale score than patients with a postoperative MPTA of 95° or less at 2years postoperatively. Level III, retrospective comparative study.

Metaphyseal sleeves as the primary implant for the management of bone defects in total knee arthroplasty after post-traumatic knee arthritis

BackgroundImplantation of a prosthesis after post-traumatic knee arthritis poses challenges derived from the bone defects and soft tissue damage. The objective of this study was to evaluate the clinical and radiological results of the use of metaphyseal sleeves in primary total knee arthroplasty surgery after post-traumatic arthritis. MethodsClinical and radiological results of 25 patients undergoing surgery for post-traumatic knee arthritis were prospectively evaluated. A semi-constrained, mobile platform prosthesis with metaphyseal sleeves was implanted. American Knee Society scales, Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the Short Form 12 Health Survey were used. Patients were evaluated at the baseline and at postoperative months three, 12, and annually until final follow-up. ResultsThe mean follow-up was 79 months with a maximum of 10 years. Mean Knee Society Score (KSS) increased from 29 to 78, and functional KSS from 42 to 81.The average WOMAC pain index changed from 12 to three; average WOMAC stiffness improved from four to one, and WOMAC function score improved from 44 to 16.The mean physical SF12 varied from 30 to 46, while mental SF-12 varied from 45 to 55.Radiological osseointegration of the implants was considered optimal in all cases, with a survival of 100%. ConclusionsMetaphyseal sleeves in combination with varus–valgus constrained (VVC) components and a rotating platform, have shown good clinical and radiological results in patients with post-traumatic knee arthritis and constitute a reliable alternative for treatment of this disease when the epiphyseal zone is deteriorated and has bone defects.

Proximal fibular osteotomy to treat medial compartment knee osteoarthritis: Preoperational factors for short-term prognosis.

ObjectiveThe purpose of this study was to determine the association between preoperational factors and patients’ short-term outcome after proximal fibular osteotomy (PFO) and to provide a basis for detailed surgical indication and patient selection.MethodsThis was a retrospective study of patients undergoing PFO between January 2015 and December 2015. Preoperational clinical data including gender, age, duration of disease, visual analogue score (VAS) and American Knee Society (KSS) score were collected. The radiological factors including hip-knee-ankle angle (HKA angle), condyle-plateau angle (CP angle), Kellgren and Lawrence grade (KL grade), joint space width of both compartments and settlement value were also considered. Patients were followed for at 12 months postoperatively. Both clinical and functional KSS scores were obtained. The outcome of interest was divided into clinical outcome and functional outcome. For each, two criteria were defined: satisfaction and significant improvement. Satisfaction is characterized by a KSS clinical or functional score over 70 points (excellent and good results); significant improvement refers to an increase in KSS scores of more than 15 points. Bivariate logistic regression for the association between preoperational factors and outcomes of interest was performed. Multivariable logistic regression analyses were used to detect the independent factors affecting the outcomes.ResultsA total of 84 patients and 111 knees were followed-up. Of these, 17 knees were from males and 94 were from females. The average age was 59.45±8.82 years. The average preoperational VAS score, KSS clinical and functional score were 7.08±1.41 points, 49.14±10.95 points and 44.97±17.71 points, respectively. According to KL grading, there were 17 knees of grade 2, 47 knees of grade 3, and 47 knees of grade 4. In clinical outcomes, there were 51 knees in the satisfaction group and 77 knees in the significant improvement group. In functional outcomes, 43 knees were in the satisfaction group and 76 knees in the significant improvement group. KSS clinical score (OR = 1.134, 95%CI = 1.067–1.205, P = 0.000) was the independent factor associated with clinical satisfaction. Age (OR = 1.072, 95%CI = 1.000–1.150, P = 0.048), VAS score (OR = 1.679, 95%CI = 1.041–2.706, P = 0.033), KSS clinical (OR = 1.072, 95%CI = 1.005–1.144, P = 0.034) and functional (OR = 1.100, 95%CI = 1.044–1.159, P = 0.000) score, HKA angle (OR = 1.345, 95%CI = 1.119–1.617, P = 0.002) and settlement value (OR = 7.540, 95%CI = 1.307–43.484, P = 0.024) were the independent factors associated with functional satisfaction. KSS clinical (OR = 0.905, 95%CI = 0.850–0.963, P = 0.002) score, CP angle (OR = 0.760, 95%CI = 0.593–0.973, P = 0.030) and medial joint space width (OR = 0.001, 95%CI = 0.000–0.107, P = 0.003) were the independent factors associated with significant clinical improvement; VAS score (OR = 1.582, 95%CI = 1.042–2.402, P = 0.031), KSS functional (OR = 0.888, 95%CI = 0.838–0.942, P = 0.000) score, HKA angle (OR = 1.292, 95%CI = 1.101–1.518, P = 0.002) and settlement value (OR = 9.990, 95%CI = 1.485–67.197, P = 0.018) were the independent factors associated with significant functional improvement.ConclusionsThe independent factors affecting postoperative clinical outcome after PFO were KSS clinical score, CP angle and medial joint space width. In addition, the independent factors that influenced functional outcome included age, VAS score, KSS score, HKA angle and settlement value. As objective radiological evidence, HKA angle and settlement value could be used as an important basis for patient selection for PFO.

Use of autologous bone marrow stem cell implantation for osteonecrosis of the knee in sickle cell disease: a preliminary report

BackgroundThe purpose of our study was to evaluate safety, feasibility and clinical results of bone marrow mononuclear cell (BMC) implantation for early-stage osteonecrosis of the knee (OK) secondary to sickle cell disease.MethodsThirty-three SCD patients (45 knees) with OK treated with BMC implantation in the osteonecrotic lesion were clinically and functionally evaluated through the American Knee Society Clinical Score (KSS), Knee Functional Score (KFS) and Numeric Rating Scale (NRS) pain score. MRI and radiographic examinations of the knee were assessed during a period of five years after intervention.ResultsNo complications or serious adverse event were associated with BMC implantation. From preoperative assessment to the latest follow-up, there was a significant (p < 0.001) improvement of clinical KSS (64.3 ± 9.7, range: 45–80 and 2.2 ± 4.1, range: 84–100, respectively), KFS (44.5 ± 8.0, range: 30–55 and 91.6 ± 5.8, range: 80–100, respectively) and reduction of NRS pain score (6.7 ± 1.2, range: 4–9 and 3.4 ± 1.0, range: 2–5, respectively). In total, 87% of patients (29/33) consistently experienced improvements in joint function and activity level as compared to preoperative score. No patient had additional surgery following BMC implantation. Radiographic assessment showed joint preservation and no progression to subchondral collapse at most recent follow-up.ConclusionsThe technique of BMC implantation is a promising, relatively simple and safe procedure for OK in SCD patients. Larger and long-term controlled trials are needed to support its clinical effectiveness.Trial registrationClinicalTrials.gov NCT02448121. Retrospectively registered 19 May 2015.

An observation of compressive cryotherapy on blood loss control after total knee arthroplasty

Objective To evaluate the efficacy of compressive cryotherapy on blood-loss control after total knee arthroplasty (TKA). Methods Fifty patients undergoing unilateral TKA were randomized into cryotherapy group and controlled group postoperatively. Patients in the cryotherapy group were treated with Iceman model 2200 cold therapy unit on the knee for 48 hours. The drainage volume of both groups was measured dynamically for 6 hours, 8 hours, 24 hours, 48 hours after the TKA. The hemoglobin and hematocrit were continuously followed up for 24 hours, 48 hours and 72 hours. The limb circumference was measured for 24 hours and 48 hours after the TKA. Postoperative 72-hour American Knee Society Score (KSS) was calculated. Results The hemorrhage volume of cryotherapy group was (198.12±8.88), (250.00±10.89), (301.00±15.44), (358.04±11.60) ml separately for 6 hours, 8 hours, 24 hours, 48 hours after the TKA and (249.88±9.21), (302.60±11.61), (369.12±13.20), (450.40±12.71) ml in the controlled group, (t=16.518-26.836, P 0.05). Conclusions Compressive cryotherapy after TKA is effective in reducing blood loss and edema, which is beneficial to early recovery and functional rehabilitation. Key words: Cryotherapy; Blood loss, operating; Nursing care; Total knee arthroplasty

Ten-Year Results of the Press Fit Condylar Sigma Cobalt-Chrome Total Knee Replacement.

Total knee arthroplasty (TKA) is reliant on safe and effective implants. The Press Fit Condylar Sigma Cobalt-Chrome (PFCSCC) was introduced in 2006, but no reports have examined long-term failure rates and patient-reported outcome measures (PROMs). The primary aim of this study was to assess survival outcomes of the PFCSCC at 10 years after implantation. Prospective data collection was performed on all patients undergoing primary TKA in one orthopaedic department using this prosthesis exclusively from February 1, 2006, to January 31, 2007. Follow-up was at 10 years. Survival analysis was performed using two primary outcome measures: (1) all-cause joint revision and (2) aseptic revision. Secondary outcomes measures included the American Knee Society Score (AKSS) and Oxford Knee Score (OKS). In total, 249 knees of 233 patients underwent primary TKA. Mean patient age was 66.7 years (range 34-80), and mean body mass index (BMI) was 30 kg/m2 (20.7-40.1). Reviewing all causes of revisions, 14 joints (5.6%) of 14 patients required reoperation. Of these, nine were for deep infection, including six in the first year. Four (1.6%) underwent aseptic revision. Mean AKSS changed from 47.6 to 90.4 (n = 140; p < 0.001) at 10 years, and mean OKS changed from 38.3 to 23.2 (n = 149; p < 0.001). Prospective analysis of consecutive TKA cases using this design of prosthesis demonstrated high survival rates of 94.4% (all-cause revision) and 98.4% (aseptic revision) at 10 years. Postoperative gains in PROMs were sustained at 10 years. These real-world data represent a substantial extension to previous reports for the PFCSCC and suggest that it is not prone to late mechanical failure.

Long-term results of mobile bearing total knee arthroplasty

Background: Total knee arthroplasty is a successful surgical procedure with a survivorship greater than 90% after 15 years. Preoperative range of motion is believed to have a large influence in the postoperative results. The mobility of the polyethylene insert permits rotation and gliding. Aims of study is to present the results of a prospective, long-term clinical follow-up of 86 patients were managed with simultaneous bilateral mobile-bearing total knee arthroplasty, and to evaluate their outcome. Patients and Methods: Patients were followed up for 92 months (range 72-102 months), 32 men and 54 women with average age 63 years. Radiographic evaluation was carried out preoperatively and postoperatively. All procedures were performed by using a standard technique, including the necessary soft-tissue release required to obtain adequate balance. Rehabilitation started on the first postoperative day assisted by a physical therapist with full weight bearing. Results: Clinical and radiographic evaluations were done on regular bases. Outcomes were measured using the American Knee Society Score and the Oxford Knee Score. The mean improvement in the postoperative arc of flexion was 30°. The average length of physiotherapy before going back to near the normal activities was 23 days. Before surgery, the average Knee Society knee score was 49.7 points and at final follow-up was 86 points. The Oxford knee score was 42 points before surgery and at final follow-up was 24 points. Both scores show significant improvements. Radiologically, the averaged varus was 16° and at final follow up was 6° of valgus. No significant complications were recorded. Conclusions: not all patients are candidates for mobile-bearing TKA, it has lower the loosening rate, and it has the ability to self-align, moreover that, the surgical technique is of paramount importance during the implantation of a mobile-bearing prosthesis.

Artroplastia total de rodilla navegada versus convencional; estudio prospectivo a 3 años de seguimiento

ObjectiveComputer-assisted surgery application in total knee arthroplasty (TKA) has shown more accurate implant alignment compared with conventional instrumentation and is associated with more homogeneous alignment results. Although longer implant survival and superior clinical outcomes should be expected from navigated TKA, currently available evidence does not support this hypothesis. The aim of this study was to compare navigated TKA with conventional TKA regarding clinical and radiological outcomes after a 3-year follow-up under the hypothesis that navigated TKA would provide better outcomes than conventional TKA. Material and methodIn a prospective multicentre study, 119 patients underwent navigated TKA and 80 patients received conventional instrumentation. Patients were evaluated at the baseline and at postoperative months 3, 12, 24, and 36. Analysis included the American Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form-12 (SF12) Health Survey, and radiographic assessment. ResultsAll clinical scores improved significantly for all patients during the follow-up but were significantly better in the navigation group.The percentage of patients showing a mechanical axis between 3° of varus and 3° of valgus was significantly higher in the ATR group (93%) than in the conventional TKA group (71%) (P<.01). ConclusionsThe use of computer-assisted surgery in TKA provides more accurate mechanical alignment and superior short-term functional outcomes compared to conventional TKA.

Instrumented gait analysis in patients with medial osteoarthritis of the knee after mobile-bearing unicompartmental knee arthroplasty

BackgroundUnicompartmental knee arthroplasty (UKA) is an effective treatment for patients with medial osteoarthritis of the knee joint. Instrumented gait analysis provides an objective measure to quantify and qualify postoperative changes of gait. The purpose of this study was to evaluate standardized instrumented gait analysis for functional recovery and gait as an outcome of mobile-bearing UKA in patients with medial osteoarthritis of the knee. MethodsTwenty-one patients with isolated medial osteoarthritis of the knee joint received mobile-bearing UKA. They were examined by a gait analysis before surgery and after an average follow-up time of seven months. Gait analysis was performed on a treadmill with six infrared-cameras to identify changes of gait characteristics (e.g., velocity, stride time, stride length, knee adduction and hip abduction). ResultsMean velocity (chosen by individuals) increased from 0.61 to 0.76m/s and further significant advancements, particularly in the knee adduction and the hip abduction were detected. Time and length of strides improved significantly as well as the clinical scores American Knee Society Score (AKSS), Oxford-12, Hannover Functional Ability Questionnaire for Osteoarthritis (FFbH-OA) Score and Devane Score. ConclusionMobile-bearing UKA can restore physiological axis of the leg and improve gait and function of the knee joint. The combination of instrumented gait analysis with clinical scores constitutes an eligible measuring instrument to quantify and qualify changes in patients' gait patterns.

Intentionally Increased Flexion Angle of the Femoral Component in Mobile Bearing Unicompartmental Knee Arthroplasty.

PurposeThe purpose of this study was to determine the results of mobile bearing unicompartmental knee arthroplasty (UKA) with an intentionally increased flexion angle of the femoral component in patients requiring high flexion.Materials and MethodsWe investigated 45 knees treated by UKA. Clinically, we measured the range of motion (ROM) and the American Knee Society (AKS) score preoperatively and at final follow-up and investigated complications. Radiologically, we measured the flexion angle of the femoral component, the posterior slope angle of the tibial component, the femorotibial angle and mechanical axis of the limb postoperatively.ResultsThe ROM was increased from 123° preoperatively to 139° at the final follow-up. The AKS knee and function scores increased from 59 and 68, respectively, preoperatively to 94 and 96, respectively, at the final follow-up. The flexion angle of the femoral component was 9.1°, and the posterior slope angle of the tibial component was 8.6°. There was one case of bearing dislocation in the largest femoral flexion angle case.ConclusionsThe results might reflect the positive effect of an increased flexion angle of the femoral component up to 10° on ROM in mobile bearing UKA, which would contribute to better quality of life after UKA especially in populations requiring deep knee flexion.

Robotic-Arm–Assisted vs Conventional Unicompartmental Knee Arthroplasty. The 2-Year Clinical Outcomes of a Randomized Controlled Trial

BackgroundUnicompartmental knee arthroplasty (UKA) for treatment of medial compartment osteoarthritis has potential benefits over total knee arthroplasty but UKA has a higher revision rate. Robotic-assisted UKA is increasingly common and offers more accurate implant positioning and limb alignment, lower early postoperative pain but evidence of functional outcome is lacking. The aim was to assess the clinical outcomes of a single-centre, prospective, randomised controlled trial, comparing robotic-arm-assisted UKA with conventional surgery. MethodsA total of 139 participants were recruited and underwent robotic-arm-assisted (fixed bearing) or conventional (mobile bearing) UKA. Fifty-eight patients in the robotic-arm-assisted group and 54 in the manual group at 2 years. The main outcome measures were the Oxford Knee Score, American Knee Society Score and revision rate. ResultsAt 2 years, there were no significant differences for any of the outcome measures. Sub-group analysis (n = 35) of participants with a preoperative University of California Los Angeles Activity Scale >5 (more active) was performed. In this sub-group, the median Oxford Knee Score at 2 years was 46 (IQR 42.0-48.0) for robotic-arm-assisted and 41 (IQR 38.5-44.0) for the manual group (P = .036). The median American Knee Society Score was 193.5 (IQR 184.0-198.0) for the robotic-arm-assisted group and 174.0 (IQR 166.0-188.5) for the manual group (P = .017). Survivorship was 100% in robotic-arm-assisted group and 96.3% in the manual group. ConclusionOverall, participants achieved an outcome equivalent to the most widely implanted UKA in the United Kingdom. Sub-group analysis suggests that more active patients may benefit from robotic-arm- assisted surgery. Long term follow-up is required to evaluate differences in survivorship.

A prospective randomized controlled study of total knee arthroplasty via mini-subvastus and conventional approach

To compare the clinical and radiographic results between primary total knee arthroplasty (TKA) via mini-subvastus or conventional approach through a prospective randomized controlled study. Ninety-four patients (104 knees) undergoing primary TKA between January 2011 and April 2012 were evaluated and randomly divided into 2 groups. Forty-six patients (52 knees) underwent TKA via conventional approach (conventional approach group), and 48 patients (52 knees) underwent TKA via mini-subvastus approach (mini-subvastus approach group). In these patients, 45 cases (51 knees) in conventional approach group and 45 cases (49 knees) in mini-subvastus approach group were followed up and recruited in the final analysis. There was no significant difference in age, gender, body mass index, sides, osteoarthritis grading, American Knee Society Score (KSS), Hospital for Special Surgery (HSS) score, visual analogue scale (VAS), range of motion (ROM) of knee between 2 groups ( P>0.05). The clinical indexes were recorded and analyzed, including the operation time, length of incision, total blood loss, blood transfusion after operation, hospital stay time, the time of performing straight leg raise, incision condition, VAS score, ROM of knee, HSS score, and KSS score, hip-knee-ankle angle (HKA), femoral anatomic axis and the femoral prosthesis joint angle (femoral angle), tibia anatomic axis and tibial prosthesis joint angle (tibial angle), femoral prosthesis flexion angle (FPFA), and posterior slope angle (PSA) of the tibial plateau. All patients were followed up. The average follow-up time was 66.4 months (range, 60.0-72.5 months) in conventional approach group and 65.6 months (range, 60.0-71.2 months) in mini-subvastus approach group. Compared with the conventional approach group, the incision of mini-subvastus approach group shortened, the operation time prolonged, and the time when patients started straight leg raise exercises was earlier; showing significant differences between 2 groups ( P<0.05). There was no significant difference in hospital stay time, total blood loss, and numbers of blood transfusion between 2 groups ( P>0.05). The complication rate was 8.2% (4/49) in mini-subvastus approach group and 0 in conventional approach group, showing no significant difference between 2 groups ( P=0.054). At 1 and 3 days, the VAS and the ROM of knee in mini-subvastus approach group were significantly better than those in conventional approach group ( P<0.05); but there was no significant difference in above indexes between 2 groups at 14 day ( P>0.05). There was no significant difference in HSS and KSS scores between 2 groups at the 1, 3, 6, 12 months and 3, 5 years ( P>0.05). X-ray film showed no aseptic loosening in all cases. There was no significant difference in the measured values and incidence of abnormal patient of HKA, femoral angle, tibial angle, FPFA, and PSA at last follow-up between 2 groups ( P>0.05). TKA via mini-subvastus approach is helpful to the early function recovery of knee, but the long-term effectiveness is consistent with TKA via conventional approach. As the limited exposure, TKA via mini-subvastus spproach may has high risk of operative complications.

Complex Tibial Plateau Fractures Treated by Hybrid External Fixation System

Background:Tibial plateau fractures are common due to high energy injuries. The principles of treatment include respect for the soft tissues, restoring the congruity of the articular surface and reduction of the anatomic alignment of the lower limb to enable early movement of the knee joint. There are various surgical fixation methods that can achieve these principles of treatment. Recognition of the particular fracture pattern is important, as this guides the surgical approach required in order to adequately stabilize the fracture. This study evaluates the results of the combined treatment of external fixator and limited internal fixation along with the advantages using postoperative computed tomography (CT) scan after implant removal. Materials andMethods:55 patients with a mean age of 42 years (range 17–65 years) with tibial plateau fracture, were managed in our institution between October 2010 and September 2013., Twenty fractures were classified as Schatzker VI and 35 as Schatzker V. There were 8 open fractures (2 Gustilo Anderson 3A and 6 Gustilo Anderson 2). All fractures were treated with closed reduction and hybrid external fixation (n = 21/38.2%) or with minimal open reduction internal fixation and a hybrid system (n = 34/61.8%). After the removal of the fixators, CT-scan was programmed for all the cases, for correlation with the results. At final followup, the American Knee Society Score (AKSS) was administered.Results:All patients were evaluated with a minimum of 12 months (range 12–21 months) followup. Average time to union was 15.5 weeks (range 13–19 weeks). The postoperative joint congruity as evaluated in the postoperative CT-scan was <2 mm of articular step-off in 8 patients (14.5%), between 2 and 4 mm in 18 patients (32.7%) and over 4 mm in 29 (52.7%). The injured limb mechanical axis was restored within 5° compared to the contralateral limb in 36 cases (65%) and with an angulation >5° in 19 cases (35%). Patients with residual joint depression <3.5 mm had a 95% chance of having excellent AKSS knee score results and 80% chance of having excellent AKSS function scores. On the other hand, residual joint depression of >4.5 mm displayed a 100% chance of getting poor-fair scores both in AKSS knee and AKSS function score. The association of a postoperative mechanical axis within 5° of the contralateral limb and improved knee scores was statistically significant for the AKSS function and total scores but not for the AKSS knee score. The AKSS was negatively correlated with postoperative joint depression magnitude which was statistically significant. Only the amount of joint collapse was verified as a prognostic factor in a multivariate logistic regression analysis.Conclusions:The postoperative CT-scan shows important information about bone healing, and an exact image of the reduction and the shaft alignment. Postoperative radiographs may have led to an underestimation of the degree of residual displacement. On the contrary, CT-scan demonstrates the exact grade of articular displacement and depending on CT-scan results one can better manage the postoperative rehabilitation.