Varus Deformity Of Knee Research Articles

Osteoarthritis and bone structural changes

Bone morphological abnormalities, such as acetabular dysplasia, femoroacetabular impingement (FAI) , and knee varus deformity, are causes of osteoarthritis (OA) . These deformities have complex three-dimensional characteristics, and an accurate image assessment is not always easy. In recent years, statistical shape models (SSM) have been applied to analyzing variations of bone morphology in OA. Bone microstructural changes in OA include bone sclerosis, subchondral cysts, and osteophytes. Recent studies show that various pathological changes in subchondral bone affect the onset and development of OA, becoming targets for new drugs. Quantitative methods to analyze the subchondral trabecular bone of OA patients using MDCT and 3TMRI are currently under development.

Reticular Telangiectatic Erythema After Total Knee Replacement Surgery: A Report of Two Cases.

In 1981, Gensch and Schmitt described a case of reticular telangiectatic erythema (RTE) associated with a cardiac pacemaker device1. RTE is clinically characterized by an asymptomatic or mildly pruritic cutaneous eruption that presents as a blanching redness in a netlike or blotchy pattern on or near the site of an implant. The occurrence of RTE in association with nonorthopaedic devices such as cardiac pacemakers has previously been reported, mostly in the dermatology literature2-16. In these reports, the appearance of RTE often occurred after the implantation of the devices, with a time frame ranging from fifteen days to four years. We report two cases of RTE that were associated with orthopaedic implants. RTE of the knee after joint replacement surgery is a benign skin reaction that can be mistaken for cellulitis, infection associated with the prosthesis, tinea corporis (ringworm), or allergic contact dermatitis to the metallic or nonmetallic components of the medical prosthesis. The patients were informed that data concerning their cases would be submitted for publication, and they both provided consent. Case 1. A sixty-six-year-old man presented with a red rash on the inferolateral aspect of the left knee near a surgical scar. He had previously undergone a total left knee arthroplasty with the P.F.C Sigma Revision Knee System (DePuy Orthopaedic, Warsaw, Indiana) for severe degenerative osteoarthritis changes with varus knee deformity. Six months after the knee surgery, what appeared to be a red skin rash was observed adjacent to the surgical scar. The involved area was mostly asymptomatic other than being “more red” after a warm shower. The patient reported that he has had a “metal allergy all of my life.” Physical examination demonstrated …

Accuracy of Image-Free Computer Navigated Total Knee Arthroplasty Is Not Compromised in Severely Deformed Varus Knees

In severe varus knee deformity, image-free computer navigated total knee arthroplasty (TKA) may result in a malaligned knee. The aim of this study was to compare the results of 17 severe varus knees (≥20°) and 81 varus knees (<20°) that underwent image-free computer navigated TKA and analyze postoperative malalignment. Computer navigated TKA was performed according to standard protocol, and component angles and mechanical axes were evaluated postoperatively with weight bearing full-length standing radiographs. All severe varus knees were corrected to within 3° of neutral lower limb alignment despite having a mean preoperative varus deformities of 22.4°. Neutral alignment was obtained in 88.9% of the varus group (mean preoperative varus deformity of 11.7°), without significant difference between the two groups. No significant difference was found in either the femoral or tibial component angles, or in the frequency of complications. Severity of varus deformity did not affect the accuracy of image-free computer navigated TKA.

Magnitude of knee osteoarthritis and associated risk factors among adult patients presenting in a family practice clinic in Nigeria

Background: Knee osteoarthritis is a chronic medical condition of public health importance in this setting. It is mostly diagnosed when preventive measures are no longer practicable due to reliance on the radiological diagnosis. Objectives: To determine the magnitude and risk factors associated with knee osteoarthritis among adult patients presenting at the University College Hospital, Ibadan, Nigeria. Materials and Methods: This cross-sectional study used a semi-structured questionnaire to interview 400 respondents. Knee osteoarthritis was diagnosed clinically using the American College of Rheumatology (ACR) criteria. Results: The point prevalence of knee osteoarthritis was 11.5%. Increasing age, female gender, marital status, low educational status, financial dependency, poor income, obesity, previous knee injury, epigastric pain, peptic ulcer disease, varus deformity of the knee, and poor health status were significantly associated with knee osteoarthritis. Logistic regression analysis showed increasing age (OR = 2. 874, CI = 1. 294-6.381), history of epigastric pain (OR = 57. 044, CI = 1. 693-192.24) and varus deformity of the left knee (OR = 3. 012, CI = 1. 063-8.547) to be the most significant factors associated with knee osteoarthritis.Conclusion: The magnitude of clinical knee osteoarthritis is high among respondents in this hospital-based study. Doctors in primary care should screen patients at first-contact to detect osteoarthritis early and manage appropriately.

Tibial slope alteration in medial open-wedge high tibial osteotomy with and without a bone graft: a double cohort study

Introduction Medial open-wedge high tibial osteotomy (OWHTO) has become one of the most common procedures for correction of varus knee deformities. The need for an autogenous bone graft with its associated morbidity and a change in the posterior tibial slope with its sequelae are some of its potential drawbacks. Patients and methods Ninety-two patients with varus deformities and medial compartment osteoarthritis were prospectively divided into two groups: group I, comprising patients who had undergone an OWHTO with an iliac crest graft, and group II, comprising patients who had undergone an OWHTO without a bone graft. These two groups were compared with respect to the posterior tibial slope, radiological outcome, and functional outcome of the two techniques. Results There was no significant difference between the two groups with regard to the correction achieved in femorotibial angle or posterior tibial slope. A significant increase was observed in both groups when preoperative and postoperative measurements were compared. Both groups showed improved functional results on the knee society knee scoring system, with no significant difference between them. Conclusion OWHTO can be performed without a graft with less operative time and with similar clinical and radiological results in terms of bone union and posterior tibial slope alteration.

Radiologic Changes of Ankle Joint after Total Knee Arthroplasty

The authors noticed that ankle joint osteoarthritis was not uncommon when lower extremity malalignment, such as a knee varus deformity, was present as a result of severe osteoarthritis of the knee. The purpose of this study was to analyze radiologic changes of the ankle joint after total knee arthroplasty. This study included 142 cases in 110 patients who underwent total knee arthroplasty and were followed for at least 3 years. The varus knee group included 128 cases and the valgus knee group included 14 cases. On anteroposterior standing lower extremity radiographs, varus and valgus angles of the knee were measured preoperatively and at the last follow-up. The angle between the ground surface and the distal tibial plafond as well as the upper talus was also measured. In addition, tibial anterior surface angle, talar tilt, space between the medial malleolar distal tip and the medial articular surface of the talus, and medial tibiotalar joint space of the ankle joint were measured. Out of 142 cases, 50 (35.2%) had arthritis in the ankle before total knee arthroplasty and 31 (21.8%) had newly developed or progressive arthritis after surgery. In particular, the varus knee group demonstrated statistically significant differences in preoperative varus deformity, preoperative talar tilt, and postoperative correction angle between the cases that developed or had progressive arthritis and those that did not show any changes (p < .05). After total knee arthroplasty, arthritis developed or progressed in the ankle of many cases radiographically. In particular, when the preoperative talar tilt increased medial to the ankle or the postoperative correction angle was large, the incidence of arthritis in the ankle joint increased. The authors recommend more cautious follow-up on the symptoms of the ankle joint after total knee arthroplasty.

Anatomy and Clinical Implications of Ultrasound-Guided Selective Femoral Nerve Block

In this study we evaluated the anatomic basis and clinical findings of ultrasound-guided femoral nerve block performed close to the distal apex of the femoral triangle. Cadaver studies were conducted in 9 thighs of fresh bodies within 24 hours postmortem. In all cases, during injection of 10 mL of blue dye, the skin proximal to the injection site was compressed to prevent the proximal flow. In the first thigh, from the area just distal to the inguinal ligament, an epidural catheter was advanced distally beneath the fascia iliaca over the femoral nerve. In the remaining cases, 10 mL of blue dye was injected into the femoral nerve at the level of the proximal adductor canal and dye spread was evaluated after local dissection. The clinical study was conducted in 20 patients with severe varus deformities. Ten milliliters of 0.75% ropivacaine was injected as in the cadaveric series. The femoral nerve was successfully dyed in all cases of the cadaver study, whereas the muscular branch to the sartorius muscle and quadriceps muscle, with the exception of the vastus medialis muscle, evaded dyeing. All 20 patients with varus knee deformities reported analgesia; none of them experienced motor block. We conclude that local anesthetic injection at the site where the superficial femoral artery has passed beneath the medial border of the sartorius muscle (8 to 12 cm distal to the inguinal crease), combined with efforts taken to prevent proximal flow may anesthetize the sensation of the anterior-to medial aspect of the knee and motor branch of the vastus medialis muscle, without blocking the sartorius or quadriceps muscles.

Growth Plate Fractures of the Distal Femur

Growth plate fractures of the distal femur are challenging to treat, with complications that require a secondary surgery 40% to 60% of the time. These fractures often necessitate operative intervention, even in the youngest patients and even with minimal apparent displacement. Treatment varies with the Salter-Harris (SH) classification and with the extent of initial displacement, ranging from simple casting for nondisplaced SH I fractures to open reduction and internal fixation for almost all SH III and IV fractures. Poor outcomes have been associated with pediatric fracture care of SH III and IV in 29% to 32% of cases. There are many pitfalls that have to be avoided in the treatment of these fractures to prevent malunion, growth arrest, and posttraumatic arthritis.

Ibalance osteotomy in early treatment of osteoarthritis

Ibalance osteotomy in early treatment of osteoarthritis

Correction of posttraumatic varus and valgus knee deformities using the Taylor Spatial Frame

Objective To evaluate the clinical outcomes and correction accuracy of posttraumatic varus and valgus knee deformities using the Taylor Spatial Frame (TSF).Methods From June 2006 to December 2010,26 patients with posttraumatic varus and valgus knee deformities who had been treated with the TSF combined with less invasive high tibial osteotomy (HTO) or supracondylar femur osteotomy (SFO) were retrospectively analyzed,including 19 males and 7 females with an average age of 39 years.There were 20 cases of posttraumatic varus knees and 6 valgus knees.Twenty one patients were treated with HTO and 3 with SFO,2 with HTO and SFO simultaneously.During the operation,the TSF was firstly assembled and then the parameters of the frame were measured followed by less invasive percutaneous osteotomy.Correction was started seven to ten days after the operation following the time schedule provided by the computer program.Correction of the struts were performed 3 times per day,with a total movement of 0-3 mm.Results Through 7-35 days frame adjustments,20 cases of deformities were fully corrected.X-ray showed that the mechanical axis deviations of the tibia and femur all were recovered to normal range,and the deformity of rotation,angulation and crispation were fully corrected.Six cases had residual slight angulation or crispation deformity ( ＜ 4° or ＜ 10 mm).Through the second 4-10 days frame adjustments,these 6 cases of deformities were fully corrected finally.New bone formation and consolidation on the osteotomy site were good.The fixators were removed from 2.5-6.0 months after surgery and the appearance of the limbs and the patients' gait recovered to normal and the keen pain disappeared.All patients were followed up for 12-60 months and without the recurrence of the deformity.Eleven cases occured pin site infection and were controlled by use of the sensitive antibiotics.One case occured refracture of the distal femur osteotomy site 1.5 months after frame removal.Through conservative treatment,the fracture finally healed.Conclusion Posttraumatic varus and valgus knee deformities can be effectively corrected by using TSF and with a high accuracy. Key words: External fixators; Osteotomy; Knee joint; Abnormalities

Open-wedge high tibial osteotomy: comparison between manual and computer-assisted techniques

The purpose of our study was to compare clinical and radiological results of two groups of patients treated for medial compartment osteoarthritis of the knee with either conventional or computer-assisted open-wedge high tibial osteotomy (HTO). Goals of surgical treatment were a correction of the mechanical axis between 2° and 6° of valgus and a modification of posterior tibial slope between -2° and +2°. Twenty-four patients (27 knees) affected by varus knee deformity and operated with HTO were prospectively followed-up. They were randomly divided in two groups, A (11 patients, conventional treatment) and B (13 patients, navigated treatment). The American Knee Society Score and the Modified Cincinnati Rating System Questionnaire were used for clinical assessment. All patients were radiologically evaluated with a comparative lower limb weight-bearing digital radiograph, a standard digital anteroposterior, a latero-lateral radiograph of the knee, and a Rosenberg view. Patients were followed-up at a mean of 39months. Clinical evaluation showed no statistical difference (n.s.) between the two groups. Radiological results showed an 86% reproducibility in achieving a mechanical axis of 182°-186° in group B compared to a 23% in group A (p=0.0392); furthermore, in group B, we achieved a modification of posterior tibial slope between -2° and +2° in 100% of patients, while in group A, this goal was achieved only in 24% of cases (p=0.0021). High tibial osteotomy with navigator is more accurate and reproducible in the correction of the deformity compared to standard technique. Therapeutic study, Level II.

High, open wedge tibial osteotomy: Finite element analysis of five internal fixation modalities

Medial open wedge tibial osteotomy is one of the most widely accepted method of treatment for varus knee deformity in younger patient population. Its success depends on the quality of fixation and preservation of the outer cortex of the tibia. The aim of the study was to evaluate stress distribution in five numerically designed plate configurations which can be used in open wedge tibial osteotomy. The paper describes the 3D numerical model of the tibia with 10 degrees varus deformity correction obtained by an optical scanner ATOS. The simulation anticipated axial compressive loads of 700 N, 1 400 N and 2 100 N. We used a modification of the standard T-plate in all of the five tested models. Modalities were tested with and without a metal block, and with and without a stable angle fixation plates and screws. Software PAK was used in the analysis of stress distribution. With exception for the standard T-plate configuration without the supporting block, the loads up to 1400 N did not result in critical stresses on the outer cortex of the tibia in the remaining four models. There is an objective risk of possible failure of the outer cortex and loss of correction at a load of 2100 N in all configurations. The plate model with the angle stable fixation and the supporting metal block showed the most optimal distribution of stresses on the plate-bone composite compared to other models. The standard T-plate configuration without supporting metal block is not sufficient to stabilize the open wedge osteotomy of the tibia. Numerical models of the angle stable T-plate and the supporting metal block achieved a favorable distribution of stresses on the bone and implant which require further biomechanical testing.

Computer-Assisted High Tibial Osteotomy: Preliminary Results

Open-wedge high tibial osteotomy (HTO) is an established technique for the treatment of symptomatic varus malaligned knees. In this study, we prospectively followed up 13 patients (14 knees) who underwent navigation system-supported HTO for varus knee deformity. Preoperatively all patients underwent a physical examination, and anteroposterior and laterolateral lower limb weight-bearing digital radiographs were obtained. The following parameters were examined: (1) Insall-Salvati index; (2) posterior tibial slope angle; (3) mechanical femorotibial angle; (4) inferior limb length. At a mean follow-up of 12.6 months, clinical examination showed satisfactory results in all patients. The mean Modified Cincinnati Rating System Questionnaire rating increased significantly from 46.5 ± 7.2 to 84.6 ± 8, while the mean Knee Society Score increased significantly from 51.4 ± 9.9 to 85.1 ± 7.3. The mean Insall-Salvati index changed from 1.11 preoperatively to 1.10 postoperatively (P=.742). According to the navigation system data, the femorotibial mechanical axis was corrected from a varus of 6.3° ± 1.9° to a valgus of 2.1° ± 1.6°. These data matched postoperative radiographic lower limb weight-bearing data. In the group of patients in whom we evaluated the posterior tibial slope with the navigation system, we detected an increase of 0.3° ± 0.4° compared with the preoperative radiographic examination evaluations; the comparison between the postoperative and the preoperative radiograhic examination results showed an increase of 0.5° ± 0.7° (P=.87). The results of our study seem to show greater accuracy of mechanical axis correction and smaller increase in tibial slope when a navigation system is used in open-wedge HTO.

A Case of Bilateral Revision Total Knee Arthroplasty due to Varus Knee Deformity Associated with Foreign Body Reaction in One Knee and Recurrent Rheumatoid Synovitis in the Other

A Case of Bilateral Revision Total Knee Arthroplasty due to Varus Knee Deformity Associated with Foreign Body Reaction in One Knee and Recurrent Rheumatoid Synovitis in the Other

Opening-wedge high tibial osteotomy without bone graft

Open wedge high tibial osteotomy has become the trend for correction of varus knee deformities. The drawbacks were the need of autogenous bone graft with its associated morbidity, and later the use of bone substitutes with their cost and delayed healing. In this study, a total of 58 consecutive patients underwent high tibial osteotomy with internal fixation by wedge (toothed) plate and screws without bone graft, from 2004 to 2008. Age of the patients ranged from 24 to 65 years. There were 37 women and 21 men. The osteotomy opening size ranged from 8 to 14 mm. The mean follow-up was 38 months. The osteotomy united in all patients. Average time to union was 12.4 weeks (range 8-16 weeks). Partial loss of correction occurred in one osteotomy. There was significant difference between the healing time and the size of the osteotomy opening. The results at the final follow-up using the HSS score were excellent in 51 knees (88%) and good in seven knees (12%). Despite the routine addition of bone graft as a part of the high tibial osteotomy procedure, this study supports medial opening-wedge high tibial osteotomy up to 14 mm without bone graft or bone substitutes, which shortens the operative time and avoids unnecessary morbidity.

Sudden Peroneal Nerve Palsy in a Varus Arthritic Knee

Peroneal nerve palsy has been reported in association with traumatic and nontraumatic causes. We encountered a 75-year-old man whose peroneal nerve palsy developed suddenly following varus deformity of the arthritic knee. A review of the literature found 1 other report describing a progressive peroneal nerve palsy associated with a varus deformity of the knee due to arthritis. Our patient had progressive intractable knee pain; 3-compartment, severe degenerative changes in the knees; varus knee malalignment and laxity; right peroneal nerve palsy; and decreased sensation to light touch and pinprick on the dorsum of the right foot. The preoperative WOMAC score was 36. Nerve conduction studies confirmed acute peroneal neuropathy with conduction block at the fibular neck and secondary axonal degeneration. Magnetic resonance imaging of the knee showed osteophytes and cysts surrounding the fibular neck. Although their compression could be responsible for the nerve palsy, the sudden process made this less possible. Thus, the patient underwent total knee arthroplasty of both knees without exploration of the nerve. At 5-month follow-up, the WOMAC score was 78. The patient walked with a cane with no varus thrust, and his right knee had no varus laxity in full extension. The peroneal nerve did not retain its function. Sensory examination and postoperative nerve conduction studies showed no improvement.

Magnetic resonance imaging signs of iliotibial band friction in patients with isolated medial compartment osteoarthritis of the knee

The purpose of this retrospective study was to assess the frequency of magnetic resonance imaging (MRI) signs of iliotibial band friction (ITBF) in patients with advanced medial compartment knee osteoarthritis. Proton density-weighted (PDw) fat-saturated (fatsat) MR images (1.5 T, slice thickness (SL) 2.5-3 mm, eight-channel phased array coil) of 128 patients with isolated advanced osteoarthritis of the medial knee compartment and complete or subtotal (>80%) loss of cartilage were evaluated. There were 41 men and 87 women. Mean age was 63 years, range 34-89 years. The control group consisted of 94 patients with medial meniscus degeneration without cartilage loss (56 men and 38 women, mean age 50 years, range 16-89 years). MRI signs of ITBF were evaluated in both groups [poorly defined abnormalities of signal intensity and localized fluid collection lateral, distal or proximal to the lateral epicondyle; signal intensity abnormalities superficial to or deep by the iliotibial band (ITB)]. Transverse images were evaluated separately. Consensus evaluation using all imaging planes was performed. Of 128 patients with osteoarthritis, 95 had moderate or advanced MRI signs of ITBF (74.2%). Eighty-nine patients (69.5%) had advanced degeneration of the meniscus. In the control group, 26 of 94 patients had only moderate MRI signs of ITBF. There was a statistically significant difference between both groups for the presence of MR signs of ITBF (P <or= 0.01). MRI signs of ITBF were frequently present in patients with severe medial compartment osteoarthritis of the knee. Joint space narrowing with varus knee deformity may be a cause of ITBF.

Arthroscopy-Assisted Computer Navigation in High Tibial Osteotomy for Varus Knee Deformity

To assess the accuracy of knee alignment after high tibial osteotomy (HTO) for varus knee deformity using arthroscopy-assisted computer navigation. Six men and 4 women aged 47 to 53 (mean, 49) years underwent medial open wedge HTO for varus knee deformity and medial unicompartmental osteoarthritis using arthroscopy-assisted computer navigation with fluoroscopy. Patients were followed up for a mean of 23 (range, 11-32) months. Intra- and post-operative leg alignments were compared. The mean postoperative coronal plane alignment was 2.7 (range,1-4) degree valgus; the mean deviation from intra-operative computer images was one (range, 0.1-1.9) degree; 5 knees had less valgus in the postoperative radiographs than the intra-operative computer images. Despite being more technically demanding, time consuming, and costly, arthroscopy-assisted computer navigation is safe, accurate, and reliable for HTO.

Reply to Letter to the Editor: Early Outcome of TKA with a Medial Pivot Fixed-bearing Prosthesis is Worse than with a PFC Mobile-bearing Prosthesis

We appreciate Mr. Scott’s comments regarding our article “Early Outcome of TKA with a Medial Pivot Fixed-bearing Prosthesis is Worse than with a PFC Mobile-bearing Prosthesis” [1]. Mr. Scott suggested osteoarthritis in the knee must differ in its presentation in the Korean population from that encountered in Western society where the need for bilateral TKAs remains the exception rather than the norm and that difference may limit the general applicability of the Korean findings. Presentations of osteoarthritis in the knee in Korean patients are similar to presentations for Western patients except for the preponderance of female patients and varus knee deformity in the majority of patients. We did not manipulate the study although we excluded patients with rheumatoid arthritis because we have few such patients for TKAs and because the polyarticular involvement in these patients means functional assessment after TKA would not provide comparable outcomes. We do appreciate Mr. Scott’s observation of numerous errors in our text. We also found some of these errors after we returned the galley proofs; however, because the article already was published electronically, no additional changes or corrections could be made. “We excluded three patients postoperatively” should be corrected to two patients. The preoperative ranges of motion for the two designs were 124° and 123°, as stated in the text. In Table 2, 124° should be corrected to 123°. In Table 3, 38 of 92 (63%) should be corrected to 41%, and 51 of 92 (34%) should be corrected to 55%. We did not notice the errors in Table 6 when we submitted the manuscript or on the galley proofs. The numbers for PFC Sigma should be corrected to: We defined postoperative range of motion as insufficient if it was less than 120°. The range of motion at final followup was less (p = 0.007) for the Medial Pivot fixed-bearing prosthesis than for the PFC Sigma (mean ± standard deviation, 115° ± 18.0° versus 127° ± 12.1°, respectively). Therefore, the patients’ opinion regarding their range of movement concurred with our assertion. We perform a high volume of bilateral simultaneous TKAs, thereby allowing for large numbers in the limited period of the study. The first author (YHK) performed the TKAs using the Medial Pivot prosthesis in 15 cases before commencing the trial. We submitted a spreadsheet of our raw data to the editor during the editorial process. He requested it again with this letter and we submitted it again. Antibiotics were administered for 48 hours in every patient who had a TKA. We performed ligament balancing in Medial Pivot and PFC Sigma mobile-bearing TKAs. However, additional time was required for ligamentous balancing in mobile-bearing TKAs to prevent dislocation of the rotating platform. You may be correct in using only the AKSS scoring system. Our prospective study protocols have established using both systems. We are confident no bias was present in the radiographic analysis. The series has only 2.6 years’ followup, and unless the implants were grossly malpositioned, we anticipate the radiographic findings in the two groups would not differ in a short-term followup. The variables of data in this article were continuous and normally distributed. The sample size was not too small to test with Wilcoxon’s matched pairs signed rank test. When we started using the Medial Pivot TKA, we tried to follow the designers’ concepts of preserving and balancing the posterior cruciate ligament. From the results of our current series, we believe the posterior cruciate ligament must be resected whenever a Medial Pivot TKA is used. We are not sure whether you would interpret this as a poorer surgical technique.

Reply to Letter to the Editor: Early Outcome of TKA with a Medial Pivot Fixed-bearing Prosthesis Is Worse Than With a PFC Mobile-bearing Prosthesis

We appreciate Mr. Scott’s comments regarding our article “Early Outcome of TKA with a Medial Pivot Fixed-bearing Prosthesis is Worse than with a PFC Mobile-bearing Prosthesis” [1]. Mr. Scott suggested osteoarthritis in the knee must differ in its presentation in the Korean population from that encountered in Western society where the need for bilateral TKAs remains the exception rather than the norm and that difference may limit the general applicability of the Korean findings. Presentations of osteoarthritis in the knee in Korean patients are similar to presentations for Western patients except for the preponderance of female patients and varus knee deformity in the majority of patients. We did not manipulate the study although we excluded patients with rheumatoid arthritis because we have few such patients for TKAs and because the polyarticular involvement in these patients means functional assessment after TKA would not provide comparable outcomes. We do appreciate Mr. Scott’s observation of numerous errors in our text. We also found some of these errors after we returned the galley proofs; however, because the article already was published electronically, no additional changes or corrections could be made. “We excluded three patients postoperatively” should be corrected to two patients. The preoperative ranges of motion for the two designs were 124° and 123°, as stated in the text. In Table 2, 124° should be corrected to 123°. In Table 3, 38 of 92 (63%) should be corrected to 41%, and 51 of 92 (34%) should be corrected to 55%. We did not notice the errors in Table 6 when we submitted the manuscript or on the galley proofs. The numbers for PFC Sigma should be corrected to: We defined postoperative range of motion as insufficient if it was less than 120°. The range of motion at final followup was less (p = 0.007) for the Medial Pivot fixed-bearing prosthesis than for the PFC Sigma (mean ± standard deviation, 115° ± 18.0° versus 127° ± 12.1°, respectively). Therefore, the patients’ opinion regarding their range of movement concurred with our assertion. We perform a high volume of bilateral simultaneous TKAs, thereby allowing for large numbers in the limited period of the study. The first author (YHK) performed the TKAs using the Medial Pivot prosthesis in 15 cases before commencing the trial. We submitted a spreadsheet of our raw data to the editor during the editorial process. He requested it again with this letter and we submitted it again. Antibiotics were administered for 48 hours in every patient who had a TKA. We performed ligament balancing in Medial Pivot and PFC Sigma mobile-bearing TKAs. However, additional time was required for ligamentous balancing in mobile-bearing TKAs to prevent dislocation of the rotating platform. You may be correct in using only the AKSS scoring system. Our prospective study protocols have established using both systems. We are confident no bias was present in the radiographic analysis. The series has only 2.6 years’ followup, and unless the implants were grossly malpositioned, we anticipate the radiographic findings in the two groups would not differ in a short-term followup. The variables of data in this article were continuous and normally distributed. The sample size was not too small to test with Wilcoxon’s matched pairs signed rank test. When we started using the Medial Pivot TKA, we tried to follow the designers’ concepts of preserving and balancing the posterior cruciate ligament. From the results of our current series, we believe the posterior cruciate ligament must be resected whenever a Medial Pivot TKA is used. We are not sure whether you would interpret this as a poorer surgical technique.