Proximal Tibial Resection Research Articles

Gait analysis of patients undergoing knee endoprosthesis: functional differences between tibia and femur resections.

With the improvement in survival of patients undergoing knee reconstructive surgeries, the functional parameter became widely studied heading optimize and minimize motor sequelae. In patients undergoing knee endoprosthesis, proximal tibial or distal femoral resections affect the functioning of the knee extensor mechanism, with possible repercussions on gait. Seventeen patients were selected, divided into two groups, undergoing distal femoral or proximal tibial resection, and gait analysis examination was performed. Changes in gait velocity, cadence, step length, and alterations in the support and balance phase were observed. No major statistically significant differences were found in the kinetic and kinematic parameters between the operated groups. The study corroborates that although tibial resections have a higher theoretical risk of compromising the extensor mechanism, such data were not observed in the analyzed sample.

Influence of Preoperative Deformity on Flexion Gap Asymmetry in Measured Resection Technique: A Theoretical Study in Navigated Gap Balancing Total Knee Arthroplasties, Done for Varus Knee Osteoarthritis.

Disagreement exists on (a) achieving a symmetrical flexion gap and (b) the influence of varus deformity on the flexion gap asymmetry (FGA) in measured resection (MR) total knee arthroplasty (TKA). We aimed to determine the FGA and influence of preoperative deformity on the FGA, based on the MR technique, in varus knee osteoarthritis. In 321 navigated TKAs, we released the soft tissues in extension. In 90° flexion, with the tensioner in situ, we calculated the FGA, the angle between the posterior femoral cut (planned 3° external rotation to the posterior condylar line, parallel to the surgical transepicondylar axis, or perpendicular to the Whiteside line) and the proximal tibial resection plane. The FGA values varied widely, and the risk of >2° and >3° FGA was present in at least 60% and 40% knees, respectively. These risks were high in knees with moderate and severe varus deformity. In varus knee osteoarthritis, the risk of FGA (based on the MR technique) was high, especially when the deformity was moderate to severe. Caution is required in MR TKA, and surgeons must consider safer alternatives (gap balancing or hybrid technique) to achieve a symmetrical flexion gap in these knees.

Medial Varus Proximal Tibial Resection is Superior to Pie-Crusting of the Medial Collateral Ligament During Primary Total Knee Arthroplasty

BackgroundMedial varus proximal tibial (MPT) resection or soft tissue releases (STRs) of the medial collateral ligament (MCL) in the form of pie-crusting can be performed to achieve a balanced knee in a varus deformity. Studies comparing the 2 modalities have not been addressed within the literature. Therefore, the aims of this study were to assess the following: (1) compartmental changes between the 2 methods and (2) changes in patient-reported outcome measurements. MethodsUsing our institution’s total joint arthroplasty registry, patients who underwent primary total knee arthroplasty from January 1, 2017, to December 31, 2019, were identified. The MPT resection and STR patients were 1:1 matched with baseline parameters yielding 196 patients. Outcomes of interest included: changes in compartmental pressures at 10, 45, and 90° degrees and change to the Short-Form 12, Western Ontario and McMaster Universities Osteoarthritis Index, and Forgotten Joint Scores (FJSs) at the 2-year follow-up period. A P value less than .05 was used as our threshold for statistical difference. ResultsThe MPT resection led to significant reductions in compartmental pressures at 10° [43 versus 19 pounds (lbs.), P < .0001], 45° (43 versus 27 lbs., P < .0001), and 90° degrees (27 versus 16 lbs., P < .0001) compared to STR. MPT resection also had significantly improved Short-Form 12 (47 versus 38, P < .0001), Western Ontario and McMaster Universities Osteoarthritis Index (9 versus 21, P < .0001), and Forgotten Joint Score (79 versus 68, P = .005). ConclusionBone modification was superior to pie-crusting of the MCL in achieving consistent pressure balancing and improved outcomes. The investigation can guide surgeons on the preferred method to achieve a well-balanced knee.

The effectiveness of physeal bar resection with or without Hemi-Epiphysiodesis to treat partial growth arrest

PurposeTo evaluate the outcomes of distal femoral, proximal tibial, and distal tibial physeal bar resection combined with or without the Hemi-Epiphysiodesis procedure and provide a better understanding of the application of physeal bar resection combined with Hemi-Epiphysiodesis procedure in the treatment of physeal bar growth arrest.MethodsWe retrospectively reviewed the patients who suffered physeal bar and underwent physeal bar resection with or without the Hemi-Epiphysiodesis technique during 2010–2020. All were followed up for at least 2 years or to maturity. A modified mapping method was used to determine the area of a physeal bar by CT data. The aLDFA, aMPTA, aLDTA, MAD, and LLD were measured to assess the deformity of the lower limb.ResultsIn total, 19 patients were included in this study. The average age was 8.9 years (range 4.4 to 13.3 years old). During the follow-up, 4 (21.1%) patients had an angular change < 5°; 12 (63.2%) patients had angular deformity improvement > 5° averaging 10.0° (range 5.3° to 23.2°), and 3 (15.8%) patients had improvement of the angular deformity averaging 16.8° (range 7.4° to 27.1°). Eleven patients (57.9%) had significant MAD improvement. After surgery, we found that 7 (36.8%) patients had an LLD change of < 5 mm and were considered unchanged. Only 2 (15%) patients had an LLD improvement > 5 mm averaging 1.0 cm (range 0.7 to 1.3 cm), and 7 (36.8%) patients had increasing of LLD > 5 mm averaging 1.3 cm (range 0.5 to 2.5 cm). There were no postoperative fractures, infections, or intraoperative complications such as neurovascular injury.ConclusionPhyseal bar resection combined with Hemi-epiphysiodesis is helpful for partial epiphysis growth arrest. Without statistically verifying, we still believe that patients with limited growth ability could benefit more from physeal bar resection combined with Hemi-epiphysiodesis.

Functional Outcome Following Proximal Tibial Osteosarcoma Resection and Reconstruction by Modular Endoprosthesis

PurposeThe proximal tibia is a common location for osteosarcoma. Modular endoprosthesis is a popular reconstructive option, yet it has been associated with many complications. Our study aimed to evaluate the functional outcome and complications of proximal tibial osteosarcoma patients treated by limb salvage using modular endoprosthesis.MethodsA retrospective study of a prospective database was performed during the period between January 2000 and July 2017. Fifty-five patients with proximal tibial osteosarcoma underwent resection and modular endoprosthetic reconstruction. The functional outcome was evaluated using the Musculoskeletal tumor society scoring system and knee range of motion. Postoperative complications were classified according to Henderson classification; Type 1 (soft tissue failure), Type 2 (aseptic loosening), Type 3 (structural failure), Type 4 (infection) and Type 5 (local tumor progression).ResultsThe mean follow-up period was 71.69 ± 49.76 months. The mean musculoskeletal tumor society score was 26.5 ± 2.22; the mean range of motion was 72.63 ± 25.07, and the mean extension lag was 15.09 ± 15.38. Type 1, type 2, type 3, type 4, and type 5 complications occurred in 7.3%, 14.5%, 21.8%, 23.6%, and 5.5%, respectively. Chest metastasis developed in 10 patients (18.2%). The estimated 5-year and 10-year survival rates for the treated patients were 83.6% and 79.9%.ConclusionsProximal tibial osteosarcoma reconstruction with a modular endoprosthesis is a reliable treatment option for retaining limb function. Most complications are manageable.

Augmented reality-aided unicompartmental knee arthroplasty

PurposeTo illustrate a surgical technique for augmented reality (AR)-assisted unicompartmental knee arthroplasty (UKA) and report preliminary data.MethodsWe developed an AR-based navigation system that enables the surgeon to see the tibial mechanical axis superimposed on the patient’s leg in addition to the tibial cutting angle. We measured the tibial resection angle in 11 UKAs using postoperative radiographs and calculated the absolute difference between preoperative target angle and postoperative measured angle. The target angle was determined for each patient: mean values were 0.7° ± 1.0° varus in coronal alignment and 5.3° ± 1.4° posterior slope in sagittal alignment.ResultsThe angles measured on postoperative radiographs were 2.6° ± 1.2° varus in the coronal plane and 4.8° ± 2.5° posterior slope in the sagittal plane. The absolute differences between the target and measured angles were 1.9° ± 1.5° in coronal alignment and 2.6° ± 1.2° in sagittal alignment. No patients experienced complications, including surgical site infection and periprosthetic fracture.ConclusionThe AR-based portable navigation system may provide passable accuracy in terms of proximal tibial resection during UKA.Level of EvidenceIV

What Is the Alignment and Balance of a Total Knee Arthroplasty Performed Using a Calipered Kinematic Alignment Technique?

We simulated calipered kinematic alignment total knee arthroplasty (cKATKA) using alignment data and ligament tensions acquired during 607 consecutive robotic-assisted TKAs performed using a dynamic ligament tensor. The distal femur was resected parallel to the native joint line accounting for cartilage loss. The proximal tibial resection necessary to achieve extension gap balance was calculated for each knee. Similarly, symmetric posterior condylar resections prescribed by this method were simulated and the tibial resection needed to achieve a balanced flexion gap calculated. Finally, the resultant limb alignment and degree of joint balance in both flexion and extension of each knee were determined and categorized according to the preoperative knee alignment. Increasing preoperative varus deformity required a greater tibial varus cut to achieve a balanced extension gap (P < .0001). There was no correlation between tibial varus angle and flexion gap balance (P > .1). For mild varus deformities 81% and 95% of knees could be balanced and have an overall limb alignment within 3° and 5° from the mechanical axis respectively. For knees with moderate-severe varus, only 37% and 74% could be balanced within these alignment boundaries (P < .01). Overall, 95% of these simulated knees could be balanced with an overall alignment within 0° ± 5°. However, 50% of the simulated TKAs had looser medial gaps in flexion compared to the lateral gap. Application of the cKATKA method can yield TKAs within 0° ± 5° of mechanical axis alignment by simply adjusting the proximal tibial resection without ligament releases. However, an undesirable flexion gap balance was predicted in nearly 50% of the TKAs.

Effect of an Endoprosthetic Reconstruction Tube and Medial Gastrocnemius Flap on Extensor Mechanism Function After Oncologic Prosthesis Reconstruction of the Proximal Tibia

BackgroundExtensor mechanism reconstruction after the proximal tibial resection and implantation of a megaprosthesis is challenging. In this study, we evaluated the effectiveness of the Trevira tube and medial gastrocnemius flap in restoring extensor mechanism following the resection of proximal tibial tumor and implantation of megaprosthesis. MethodsForty patients who underwent endoprosthetic implantation following the resection of proximal tibial tumor and patellar tendon reconstruction with the Trevira tube and medial gastrocnemius flap were included. The outcome measures were knee range of motion, extensor mechanism function, patellar position, and limb function subjectively evaluated through Toronto Extremity Salvage Score and objectively through Musculoskeletal Tumor Society score. The mean follow-up of the patients was 6.1 years. ResultsThe patellar position was normal in 28 (70%) patients, patella baja in 3 (7.5%) patients, and patella alta in 9 (22.5%) patients. The mean active knee range of motion was 98.9 ± 17° (range: 85°-125°). Extension lag was present in 7 (17.5%) patients (range: 5°-20°). The mean Toronto Extremity Salvage Score of patients was 92.1 ± 6.9% (range: 85-100). The mean Musculoskeletal Tumor Society score of the patients was 87.7 ± 13 (range: 73.3-100). Postoperative complications included aseptic wound dehiscence (2 patients), aseptic loosening of the tibial component (1 patient), periprosthetic fracture in the femur (2 patients), and wound infection (1 patient). ConclusionTrevira tube combined with gastrocnemius flap augmentation is a suitable procedure for restoring extensor mechanism after proximal tibial resection and megaprosthesis implantation.

“In-house” Design and Use of 3-dimensional Printed Patient-specific Bone Tumor Resection Guides for Geometric Osteotomies in Sarcoma Surgery

Three-dimensional printing technology has rapidly advanced as a promising technology for preoperative planning, education, and surgical execution in orthopedic surgery. Use of patient-specific instrumentation in orthopedic oncology sarcoma cases can streamline complex osteotomies while providing safe margins based on predetermined osteotomy levels. We describe use of an “in-house” protocol to create patient-specific bone tumor resection guides for use in orthopedic oncology cases. The described protocol bypasses expensive outsourcing options and facilitates use of preoperative surgical simulation and intimate involvement of the surgical team in the guide design. We report on the successful design and use of three-dimensional printed patient-specific bone tissue resection guides in a case of proximal tibial parosteal osteosarcoma resection and reconstruction with a size-matched allograft, and in a case of a secondary pelvic chondrosarcoma resection.

Designing a better incision for proximal tibial osteosarcoma resection and reconstruction: a reminder of the skin's vascular anatomy.

Designing a better incision for proximal tibial osteosarcoma resection and reconstruction: a reminder of the skin's vascular anatomy.

Reconstruction of the extensor mechanism augmented with reverse transferred iliotibial band after proximal tibia tumor resection and mega-prosthetic replacement

BackgroundThe optimal procedure for functional reconstruction of the extensor mechanism after proximal tibia mega-prosthetic replacement remains unclear. MethodsSince 2006, 14 consecutive patients with aggressive bone tumors in the proximal tibia who underwent mega-prosthetic replacement were prospectively treated with reconstruction of the extensor mechanism using an ipsilateral iliotibial band. The surgical procedure consisted of wrapping the reversed iliotibial band around the tibia component, firmly suturing it to the remaining patellar tendon and tibialis anterior fascia, and covering it with a muscle flap. At the last follow up, the function was assessed based on extensor lag, active flexion of the knee, and Musculoskeletal Tumor Society score. Patellar height was measured with the Insall–Salvati ratio (ISR) preoperatively, postoperatively, and at the last follow up. ResultsAt the last follow up, the extensor lag and active flexion in 14 patients averaged 2.5° and 86°, respectively. Musculoskeletal Tumor Society score could be obtained in nine surviving patients at the last follow up and was a mean of 20.7 points. The mean ISR preoperatively, postoperatively, and at the last follow up was 1.04, 0.75, and 0.89, respectively. The extensor lag was not associated with the ISR value at any points, while reduced active flexion significantly correlated with a low ISR at the last follow up (P = 0.015). Four patients underwent additional surgeries due to postoperative infection, but none required eventual revision or amputation. ConclusionThe extensor mechanism reconstruction with the reverse transferred iliotibial band for mega-prosthetic replacement after proximal tibia resection yielded reliable outcomes with functional benefit to stabilize active knee extension.

Femoral bone growth after extendible endoprosthetic replacement of the proximal tibia in skeletally immature patients

There is increasing preference for limb salvage techniques in the management of pediatric musculo- skeletal tumors. This study was aimed at evaluating femoral growth following proximal tibia resection (PTR) and placement of an extendible endoprosthesis with sliding stem. This was a retrospective study. The demographic and clinical data were collected. All the patients with malignant tumors were fully staged and commenced on appropriate chemotherapy. An expected discrepancy of > 3cm was considered substantial enough to warrant extendible prosthesis. Twelve patients who had follow up full length scanogram of the lower limbs were included for the evaluation of femoral growth. The last available scanograms were used for growth comparison of the femur. The age at resection for all twelve patients ranged from 4-13 years. The commonest histological diagnosis was Osteosarcoma. In the twelve patients assessed for the growth of femur, the mean femoral length was 96% [89%-102%] of the unaffected femur. Distal femoral physeal growth continued after implantation of a sliding extendible prosthesis after resection of proximal tibia tumors.

Finite element analysis of the tibial component alignment in a transverse plane in total knee arthroplasty.

The research aims to analyze the tibial component rotation using the finite element method by resecting the tibia in a transverse plane at an angle between 1.5° (external rotation) and -1.5° (internal rotation). We used a three-dimensional scanner to obtain the tibia's geometrical model of a cadaveric specimen. We then exported the surfaces of the tibial geometrical model through the Computer-Aided Three-dimensional Interactive Application (CATIA), which is a Computer-Aided Design (CAD) program. The CAD program three-dimensionally shaped the tibial component, polyethylene, and cement. Our analysis determined that the maximum equivalent stress is obtained in the case of proximal tibial resection at -1.5° angle in a transverse plane (internal rotation) with a value of 12.75 MPa, which is also obtained for the polyethylene (7.693 MPa) and cement (6.6 MPa). The results have shown that detrimental effects begin to occur at -1.5°. We propose the use of this finite element method to simulate the positioning of the tibial component at different tibial resection angles to appreciate the optimal rotation.

Pedicled fibular transfer for biologic knee extensor tendon reinsertion following proximal tibial resection in pediatric osteosarcoma: Long-term outcomes.

Proximal tibial sarcoma resections result in a reconstructive challenge, necessitating joint and extensor mechanism reconstruction. The gait and functional outcomes for children reconstructed with a combination of megaprosthesis and pedicled fibular flap for extensor mechanism reconstruction, are presented. Four patients, aged 11-18 years old, were available for comprehensive analysis. The proximal tibial osteosarcoma was resected, and the reconstructive technique involved a megaprosthesis for the knee joint, used in combination with a pedicled fibula flap as a biologic structure for reinsertion of the knee extensor mechanism. Outcomes were measured with three-dimensional gait analysis and patient questionnaires. Minor postoperative wound issues occurred in some patients, requiring debridement with skin grafting. One patient fractured their transferred fibula, requiring fixation. The follow up period ranged from 1.7 to 24 years postoperatively. The longevity and quality of reconstructions were strong, measured by both objective and patient-reported outcomes. All patients reported independent walking >500m in the Functional Mobility Scale and rated their walking as a nine or 10 (out of 10) on the Functional Assessment Questionnaire. Knee society scoring revealed overall satisfaction rate of 75-80%. No patients required gait aids. The gait profile analysis revealed effective gait patterns, with patterns deviating 5.4-7° from "typical gait." Deviations >6.5° are considered abnormal. The long-term results of combining a megaprosthesis with a pedicled fibula flap for extensor reinsertion, revealed a high level of independent function. The patients performed well, without the need for aids, and gait study evidence of minimal gait deviations.

Optimal Distraction Force for Evaluating Tibiofemoral Joint Gaps in Posterior Stabilized Total Knee Arthroplasty.

Obtaining well-balanced soft tissues is important to achieve natural knee kinematics after total knee arthroplasty (TKA). In conventional procedures, soft tissue balance is evaluated with spacer blocks or lamina spreaders. However, the evaluation depends on the surgeons' experience and is not quantitative. This study aims to measure the mechanical properties of knee soft tissue with a new ligament balancer and to determine the optimal distraction force for evaluating tibiofemoral joint gaps in TKA. This study included 30 consecutive patients with medial knee osteoarthritis who were scheduled to undergo posterior stabilized TKA. The mean age of patients was 73 ± 9.6 years at the time of surgery, and the mean hip-knee-ankle angle was 13.1 ± 6.5° in varus. After distal femoral and proximal tibial resections, the tibiofemoral joint gaps under several distraction forces were measured in extension and at 90° flexion. The load-displacement curves in extension and flexion were drawn with these data, and the stability range, which was defined as the shift range from the toe region to the linear region in the curves, was calculated. The stability ranges were 160 Newtons (N) in extension and 140 N in flexion. These displacement forces were considered optimal for evaluating tibiofemoral joint gaps during surgery and ensuring knee stability after TKA.

Gait outcomes following proximal tibial tumor resection and endoprosthetic reconstruction.

Despite the proximal tibia being a common site of primary malignant bone tumors, there is limited information about gait function following proximal tibial tumor resection and endoprosthetic reconstruction (PTR). What is the impact of PTR on gait and quality of life? This was a cross-sectional study of patients ≥18 years old who were ≥2 years post-PTR compared to a control group of similar age and sex distribution. Eighteen participants (9 PTR, 9 Control) were recruited. Gait spatial-temporal data, joint kinematics and kinetics were collected at preferred and fast walking speeds. Community walking cadence, health-related quality of life (SF-36) and knee joint torque were assessed. Comparisons were performed using one-way ANOVAs with Bonferroni corrections for multiple comparisons. Nonparametric tests were used for data not normally distributed. Mean age was 31 years for each group (PTR range = 18-42 yrs, Control range = 18-44 yrs). Compared to both control and nonsurgical limbs, the surgical limb exhibited significantly decreased % single limb support time, reduced heel rise during terminal stance and an absence of normally occurring knee flexion angles, extensor moments and power generation during initial double limb support. Additionally, a reduced peak plantar flexor moment was found for the surgical as compared to the control limb. The number of gait abnormalities increased during fast walking. Significantly reduced surgical knee extensor torque on isokinetic testing and weakness of the knee and ankle on clinical examination support gait findings. During community walking, the number of low frequency strides was an average of 5.3 % greater for the PTR group (p < 0.05). Norm-based PTR group SF-36 component scores were within normal values (53.4 physical, 56.5 mental). Gait abnormalities were consistent with ankle muscle resection and transposition and knee extensor mechanism disruption. Despite these deficits, walking speed and quality of life were relatively normal.

New instrumentation system for cementless mobile-bearing unicompartmental knee arthroplasty improves surgical performance particularly for trainees

BackgroundMobile-bearing medial-unicompartmental knee arthroplasty (mUKA) has a documented learning curve. New instrumentation has been designed with the aim of reducing the technical challenges of this procedure. The primary aim of this study was to evaluate the technical performance of mUKA using new (Microplasty) versus older (Phase III) instrumentation, performed by expert surgeons and trainees. Secondary aims were to evaluate functional outcome and mid-term survivorship. MethodsA time-based comparative cohort study was performed between 2009 and 2015 at a high-volume centre. 273 patients (273 knees, 49.5% female) of mean age 67.8 (standard deviation 10.1) years underwent mUKA. 153 (56.0%) procedures used Microplasty instruments and 120 procedures (44.0%) used Phase III instruments. ResultsNon-optimal bearing usage was less frequent with Microplasty than Phase III instruments (24 knees [15.7%] versus 33 knees [27.5%], p = 0.024), with differences due to improved trainee performance. Femoral component sagittal alignment outliers were less frequent with Microplasty, but this was not statistically significant (9 knees [5.9%] versus 13 knees [10.8%], p = 0.18). Post-operative Oxford Knee Scores (OKS) were better with Microplasty (median 42 points [interquartile range 38–44]) compared to Phase III (median 39.5 points [IQR 33–44]), which was statistically significant (p = 0.023), but not clinically meaningful. The overall 5-year Kaplan-Meier (KM) survival estimate was 99.3% (95% CI 97.0–99.8%), with no differences between Microplasty and Phase III instrumentation. ConclusionsNew instrumentation improved the reliability of the proximal tibial resection in trainees. Further research is warranted to investigate whether Microplasty instrumentation shortens the learning curve for medial UKA.

Can accuracy with the iASSIST navigation be confirmed by assessment? A multi-center prospective randomized controlled trial with independent three-dimensional image assessment

BackgroundiASSIST is one of the novel accelerometer-based navigation systems for total knee arthroplasty (TKA). Although the accuracy of iASSIST compared with conventional instruments has been reported, such evaluations were performed on two-dimensional (2D) images (X-rays). This multi-center prospective randomized controlled trial aimed to assess component positioning between TKA with and without iASSIST by 3D image assessment, and to clarify whether the iASSIST provides any benefit with regard to alignment accuracy. MethodsEighty-three knees with primary knee osteoarthritis were enrolled in this study. iASSIST was used for distal femoral and proximal tibial resection in 42 knees (iA group) and a conventional guide was used in 41 knees (CONV group). At 6 months postoperatively, component alignment was evaluated with 3D images by the independent orthopaedic surgeons, and surgical parameters, range of motion and clinical outcomes were examined. ResultsThe rate of knees who have the alignment within 3° of neutral compared with the iA group and CONV group were 92.9% (39/42) vs. 87.8% (36/41) for femur and 76.2% (32/42) vs. 56.1% (23/41) for tibia in the coronal plane, respectively, whereas in the sagittal plane, the rate was 85.7% (36/42) vs. 58.5% (24/41) for femur and 83.3% (35/42) vs. 78.0% (32/41) for tibia, respectively. Compared with the CONV group, the iA group had a significantly improved femoral alignment in the sagittal plane (P = 0.006). There were no clinical or patient-reported differences at 6 months postoperatively. ConclusionsThe iASSIST provides technically high accuracy in femoral resection at TKA compared with a conventional procedure.

Functional and radiologic results of extensor mechanism reconstruction methods following proximal tibial modular endoprosthetic reconstructions: Direct versus medical textile augmented reattachment

BackgroundFollowing proximal tibial resection and modular endoprosthetic reconstruction, extensor mechanism can be reconstructed with different techniques. This study compares direct reattachment (DR) with medical textile augmented reattachment (MTAR) methods in terms of functional results and radiological results. Materials and methodsFifty-five patients (34 male, 21 female) operated between 1990 and 2015 with a minimum follow up of 24 months in a single center were evaluated retrospectively. The median age was 18 years (range: 9–64). The reconstruction was performed via MTAR (polypropylene mesh, Trevira) in 23 patients and DR in 32 patients. Incidence and degree of extension lag, degree of flexion and development of postoperative patella alta were evaluated at 3, 6 and 24 months. ResultsThe mean follow up was 78.5 months. Extension lag incidence at 24 months was 71.9% in the DR group compared with 43.5% in the MTAR group (P < 0.05).Theextensionlagratiosat 24 months in DR was 0–5° in 8.7% (n = 2), 6–10° in 21.7% (n = 5), 11–15° in 17.4% (n = 4) and > 15° in 52.2% (n = 12), respectively. Extension lag ratios at 24 months in MTAR were 0–5° in 12.5% (n = 4), 6–10° in 6.3% (n = 2), 11–15° in 6.3% (n = 2) and > 15° in 6.3% (n = 2). The mean MSTS score in DR group was 20.7 compared with 23.2 in the MTAR group (P = 0.008). ConclusionMTAR is associated with a lower incidence as well as a lower degree of extension lag. The flexion range and the incidence of patella alta are not statistically different between the groups. MSTS scores of MTAR group are significantly higher than DR group at 2-year follow up.

Effect of Posterior Tibial Slope Change on Postoperative Range of Motion and Clinical Outcomes after Posterior Cruciate-Substituting Total Knee Arthroplasty.

The posterior tibial slope (PTS) is usually adjusted by less than 5 degrees, without considering its individual difference, during posterior cruciate-substituting (PS) total knee arthroplasty (TKA). The effect of these individual changes of PTS would be important because clinical results depending on postoperative PTS were reported conflictingly. We investigated the effect of the change in PTS on the postoperative range of motion (ROM) and clinical scores after PS TKA. We retrospectively reviewed 164 knees from 107 patients who underwent PS TKA with a 2-year follow-up. We analyzed the preoperative and postoperative PTS, ROM, visual analog scale pain scale, Western Ontario and McMaster University Index (WOMAC), Hospital for Special Surgery Knee Score, Knee Society Score, and Forgotten Joint Score (FJS). The association of the absolute change in PTS with ROM and clinical scores was analyzed using correlation analysis and multiple regression analysis. As a result, the mean PTS and mean ROM changed from 9.6 ± 3.4 and 120.1 ± 15.4 degrees preoperatively to 2.0 ± 1.3 and 128.4 ± 9.3 degrees postoperatively, and the mean PTS change was 7.6 ± 3.5 degrees. The PTS change had no statistically significant association with the postoperative ROM and clinical scoring systems, although it did have a weak positive correlation with WOMAC function, No 10 (difficulty in rising from sitting) (correlation coefficient = 0.342, p = 0.041), and moderate positive correlation with the FJS, No. 6 (awareness when climbing stairs) (correlation coefficient = 0.470, p = 0.001). The authors concluded that the amount of change in PTS did not affect the postoperative ROM and clinical scores, although proximal tibial resection with a constant target of PTS resulted in individually different changes in the PTS after PS TKA.