Comparison of the outcomes of navigation-assisted revision of unicompartmental knee arthroplasty to total knee arthroplasty versus navigation-assisted primary TKA.

PURPOSE: Revision of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) is technically demanding but can be performed with computer navigation system guidance. The purpose of this study was (1) to compare the outcomes of revision of UKA to TKA to those of primary TKA and (2) to describe a surgical technique for the revision of UKA to TKA using a navigation system. METHODS: From May 2011 to April 2014, a total of 298 knees underwent primary navigation-assisted TKA (group 1), and navigation-assisted UKA revision to TKA was performed in 15 patients (group 2). One to three propensity score matching was performed to compare the two groups after a minimum of three years of follow-up. Radiographic and clinical outcomes in addition to radiolucent lines were evaluated during follow-up. RESULTS: In group 1, there was one case that required metal block augmentation with the long stem under the tibial plate due to severe bone loss, while in other cases, short stems were used, and cement and autogenous bone grafts were used to fill bone defects due to minimal bone loss. Pre- and post-operative outcomes were significantly improved in both groups (p < 0.001). There were no statistical differences between groups in pre- and post-operative outcomes except post-operative Knee Society Function Score (KSFS) (p = 0.008). There were no radiolucent lines in the tibia or femur in either group during follow-up. CONCLUSIONS: With the use of an appropriate surgical technique, navigation-assisted revision of UKA to TKA can yield clinical and radiologic outcomes comparable to those of primary navigation-assisted TKA. LEVEL OF EVIDENCE: Level IV.

Baseline varus deformity is associated with increased joint loading and pain of non-operated knee two years after unilateral total knee arthroplasty.

BACKGROUND: The goals of this study were (1) to document the gait pattern of patients with unilateral knee osteoarthritis (OA), (2) to determine the knee adduction moment (KAM) changes in the non-operated knee, and (3) to identify the predictors of change in KAM in the non-operated knee. METHODS: The study recruited 23 patients with advanced unilateral knee OA. The preoperative Kellgren-Lawrence (KL) grade of the non-operated knee was one or two; non-operated knee pain, rated using a numeric rating scale (NRS), was less than three out of 10 points. We used a commercial gait analysis system to evaluate kinetics and kinematics. Radiological and gait measurements at the two-year follow-up were compared with baseline data. RESULTS: The preoperative asymmetrical gait cycle characterized by elongation of the stance phase of the non-operated knee became symmetrical after TKA. The average KAM of the non-operated knee increased (P=0.010) and it was best predicted by the baseline mechanical axis of the non-operated knee. If the baseline mechanical axis was varus four degrees or above (varus group), the average KAM increased by 0.64 (% body weight×height, P=0.015), while for varus less than four degrees (non-varus group), KAM was unchanged. The KL grade was increased in the varus group (P=0.020) but it was unchanged in the non-varus group. Average pain NRS score was also higher (P=0.044) in the varus group. CONCLUSIONS: Close follow-up is necessary for patients with a baseline varus deformity of the non-operated knee because of the higher possibility of developing pain, subsequent arthritis and increased joint loading of the non-operated knee. LEVEL OF EVIDENCE: III, retrospective cohort study.

Anterior cruciate ligament reconstruction with quadriceps tendon-patellar bone allograft: matched case control study.

BACKGROUND: Quadriceps tendon-patellar bone (QTPB) autograft is an excellent graft option with good clinical outcome. Use of QTPB autografts have increased because they minimize donor-site morbidity including anterior knee pain, while providing adequate mechanical strength. Although, there were many clinical results about allografts that used in anterior cruciate ligament (ACL) reconstruction, it have never been reported about the clinical outcome of ACL reconstruction with QTPB allograft. The purpose of this study is to evaluate the clinical outcome of ACL reconstruction with QTPB allograft and to compare with QTPB autograft. We hypothesized that ACL reconstruction with QTPB allograft had good functional outcomes and stability and no significant difference compared to the ACL reconstruction with QTPB autograft. METHODS: From February 2009 to January 2014, 213 cases who received ACL reconstruction with QTPB grafts were included. Forty-five patients who received ACL reconstruction with QTPB allograft were individually matched in age, sex, direction of the injured knee and body mass index (BMI) to a control group of 45 patients who received QTPB autograft. Clinical results were evaluated using International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner scale, Knee injury and Osteoarthritis Outcome Score (KOOS) and ligament laxity. An average follow-up time was 31.2 months. RESULTS: The functional scores and ligament laxity improved from initial to the last visit in those with ACL reconstruction with QTPB allograft (p < 0.05). No significant statistical difference was found in clinical outcomes and complications including re-rupture between the QTPB allograft and autograft groups (p > 0.05). Laxity using anterior drawer test, Lachman test and KT-2000 showed no significant difference. No significant difference was found between the two groups in quadriceps peak extension torque, except at 60° per second at 6 months. CONCLUSION: QTPB allograft achieved good clinical outcome with no difference compared with QTPB autograft. QTPB allograft for ACL reconstruction is promising alternative to selected and compliant patients. Long-term follow-up needs to further evaluate the clinical outcomes and complications including re-rupture rate.

Mid-Term Survivals After Cementless Bipolar Hemiarthroplasty for Unstable Intertrochanteric Fractures in Elderly Patients.

BACKGROUND: Treatment of unstable intertrochanteric fracture in elderly patients remains challenging. The purpose of this prospective study is to determine clinical and radiological results of cementless bipolar hemiarthroplasty using a fully porous-coated stem in osteoporotic elderly patients with unstable intertrochanteric fractures with follow-up over 5 years. METHODS: From January 2010 to December 2011, we performed 123 cementless bipolar hemiarthroplasties using fully porous-coated stem to treat unstable intertrochanteric fractures in elderly patients with osteoporosis. Clinical and radiographic evaluations were performed. RESULTS: Fifty-three patients died and 14 patients were lost during the follow-up period. Mean follow-up period was 61.8 months postoperatively. Their mean Harris hip score was 77 points (range 36-100). None of these hips had loosening of the stem or osteolysis. Postoperative complications included nonunion of greater trochanter in 2 hips and dislocation in 2 hips. Two patients were reoperated due to periprosthetic fracture. One patient underwent implant revision due to periprosthetic infection. Thirty-one patients maintained walking activities similar to those before fracture. With follow-up period of 83 months, cumulative survival rates were 97.3% and 99.1% with reoperation for any reason and femoral stem revision as endpoint, respectively. CONCLUSION: Cementless bipolar hemiarthroplasty using a fully porous-coated stem is a useful surgical treatment option for unstable intertrochanteric fracture in elderly patients with osteoporosis.

Large meniscus extrusion ratio is a poor prognostic factor of conservative treatment for medial meniscus posterior root tear.

PURPOSE: The purpose of this study was to find a prognostic factor of medial meniscus posterior root tear (MMPRT) for surgical decision making. METHODS: Eighty-eight patients who were diagnosed as acute or subacute MMPRT without severe degeneration of the meniscus were treated conservatively for 3 months. Fifty-seven patients with MMPRT showed good response to conservative treatment (group 1), while the remaining 31 patients who failed to conservative treatment (group 2) received arthroscopic meniscus repair. Their demographic characteristics and radiographic features including hip-knee-ankle angle, joint line convergence angle, Kellgren-Lawrence grade in plain radiographs, meniscus extrusion (ME) ratio (ME-medial femoral condyle ratio, ME-medial tibial plateau ratio, ME-meniscus width ratio), the location of bony edema, and cartilage lesions in MRI were compared. Receiver operating characteristic (ROC) curve analysis was also performed to determine the cut-off values of risk factors. RESULTS: The degree of ME-medial femoral condyle and medial tibia plateau ratio of group 2 was significantly higher than group 1 (0.08 and 0.07 vs. 0.1 and 0.09, respectively, both p < 0.001). No significant (n.s.) difference in other variables was found between the two groups. On ROC curve analysis, ME-medial femoral condyle ratio was confirmed as the most reliable prognostic factor of conservative treatment for MMPRT (area under ROC = 0.8). CONCLUSION: The large meniscus extrusion ratio was the most reliable poor prognostic factor of conservative treatment for MMPRT. Therefore, for MMPRT patients with large meniscus extrusion, early surgical repair could be considered as the primary treatment option. LEVEL OF EVIDENCE: III.

Slow gait speed after bilateral total knee arthroplasty is associated with suboptimal improvement of knee biomechanics.

PURPOSE: The aim of this study was to investigate gait speed changes 2 years after bilateral total knee arthroplasty (TKA) and identify kinetic and kinematic factors associated with such changes by comparing patients with age- and sex-matched controls. METHODS: The study group included 34 female patients with end-stage knee osteoarthritis (OA) who underwent bilateral TKA and 42 age- and sex-matched controls without knee pain or OA. Standard TKA was performed on all arthritic patients with placement of posterior stabilized fixed-bearing implants. Kinetic and kinematic parameters were evaluated using a commercial optoelectric gait analysis system. Gait speed, kinetic and kinematic changes and determinants of speed were assessed via principal component analysis and multiple regression analysis. RESULTS: The average gait speed of an arthritic patient was 90.2 ± 18.4 cm/s and improved to 96.0 ± 12.3 cm/s after TKA (p = 0.032). However, the speed remained slower than that of controls (111.2 ± 8.2 cm/s, p < 0.001). With regard to kinetics, the peak knee extension moment (KEM) generated by the quadriceps was unchanged after TKA and weaker than that of controls (p < 0.001). The proportions of KEM contributing to the total sagittal moment were also smaller in the pre-/post-operative groups than in the control group (13-14% vs. 19%). On the other hand, the ankle plantar flexion moment (APFM) was increased after TKA (p = 0.007) and its proportion of the total sagittal moment was greater than in controls (46% vs. 42%). With regard to kinematics, knee range of motion (ROM) improved after TKA (p = 0.025), but was smaller than that of controls (p < 0.001). In controls, gait speed was determined principally by hip and knee joint moments. However, in the TKA group, speed was determined by the knee ROM and APFM. CONCLUSIONS: Despite showing improvement, the gait speed of TKA patients remained slower than that of controls. Slow gait speed after bilateral TKA was associated with suboptimal improvement of knee biomechanics. Quadriceps strengthening exercises and the achievement of greater ROM during gait are advised for the further improvement of gait speed. LEVEL OF EVIDENCE: Retrospective cohort study, Level III.

Arthroscopic treatment of symptomatic calcific periarthritis on the medial side of the knee after posterior cruciate ligament reconstruction: Case report and literature review.

Calcific periarthritis in the distal femur is a rare condition. Forty two year old Asian male visited to the outpatient clinic of orthopedic department with acute excruciating knee pain. The arthroscopic posterior cruciate ligament (PCL) reconstruction was performed 20 years ago with the bonepatellar tendon-bone (BPTB) autograft combined with Trevira (polyethylene terephthalate) artificial ligament. Severe tenderness was noted incidentally over the medial epicondyle area of the distal femur which the cancellous screw was inserted for PCL reconstruction, without any preceding trauma history or medial joint line tenderness due to degenerative change. The poorly defined calcific deposition was found in plain radiograph. The arthroscopic debridement of the calcification and screw removal from the distal femur was performed due to resist to conservative treatment with analgesics. After operation, the symptoms were resolved completely. The arthroscopic debridement of calcific periarthritis should be considered in specific cases, such as refractory cases with conservative management during 4-6 weeks. We present the arthroscopic treatment of the symptomatic calcific periarthritis on distal femur after PCL reconstruction can be effective.

No difference in clinical and radiologic outcomes after total knee arthroplasty with a new ultra-congruent mobile bearing system and rotating platform mobile bearing systems after minimum 5-year follow-up.

We retrospectively compared the clinical and radiographic results between 76 primary total knee arthroplasties (TKAs) using the e.motion Ultra-Congruent prosthesis and 155 primary TKAs using the Low Contact Stress rotating platform. All patients had a minimum 5-year follow-up. Range of motion, Hospital for Special Surgery score, Knee Society Knee Score and Knee Society Functional Score significantly increased in both groups postoperatively, but there was no significant difference between the two groups. The mechanical femorotibial angle improved in both groups postoperatively. Coronal and sagittal component angles were well maintained at the final follow-up. This study demonstrates that a new mobile-bearing prosthesis, designed to be highly congruent with a rotating bearing, could be considered with theoretical advantages and comparable outcomes of established mobile-bearing prostheses.

Correlation of Structural Bony Abnormalities and Mechanical Symptoms of Hip Joints.

PURPOSE: The purpose of this study is to determine structural bony abnormalities predisposing for femoroacetabular impingement by comparison of patients with and without mechanical symptoms. MATERIALS AND METHODS: We conducted this comparative study on 151 patients (151 hips; mean age 44.8 years; range 16-73 years) with mechanical symptoms with results of multi-detector computed tomography (MDCT) arthrography (the symptomatic group). Each patient was matched with a control who underwent MDCT due to ureter stone (the asymptomatic group) in terms of age, gender, site (right or left), and time at diagnosis. Acetabular evaluations, which included cranial and central anteversion and anterior and lateral center edge angles and femoral measurements, were performed. In addition, we evaluated the prevalence and characteristics of structural bone abnormalities between the two groups. RESULTS: The prevalence for patients who had at least one structural bony abnormality in the symptomatic and asymptomatic groups was 80.1% (121/151) and 54.3% (82/151), respectively (odds ratio: 3.39, 95% confidence interval: 2.30-5.66; P<0.001). The most common osseous abnormality was the isolated Pincer type in both groups: 89 (73.6%) of 121 hips with an osseous abnormality in the symptomatic group and 57 (69.5%) of 82 hips with an osseous abnormality in the asymptomatic group. By analysis of CT arthrography in symptomatic patients, a labral tear was found in 107 hips (70.9%), and 86 (80%) of these hips had a structural bony abnormality. CONCLUSION: A significantly greater prevalence rate of structural bony abnormality was observed for the symptomatic group than for the asymptomatic group. These findings are helpful for development of appropriate treatment plans.