Preoperative Mechanical Axis Deviation Research Articles

Simultaneous correction of leg length discrepancy and angular deformity of the distal femur with retrograde Precice nails: a retrospective analysis of 45 patients.

Magnetically controlled motorized intramedullary lengthening nails (ILNs) can be employed for simultaneous correction of angular deformities of the distal femur and leg length discrepancy. This spares typical complications of external fixators but requires precise preoperative planning and exact intraoperative execution. To date, its results are insufficiently reported. We aimed to elucidate the following questions: (i) Is acute angular deformity correction and gradual femoral lengthening via a retrograde ILN a reliable and precise treatment option? (ii) What are the most common complications of treatment? Acute angular deformity correction and subsequent gradual lengthening of the distal femur with retrograde ILN was retrospectively analyzed in 45 patients (median patient age: 15 years, interquartile range [IQR] 13-19 and median follow-up: 40 months, IQR 31-50). Outcome parameters were accuracy, precision, reliability, bone healing, and complications of treatment. The median distraction was 46 mm (IQR 29-49), median distraction and consolidation index 0.9 mm/day (IQR 0.7-1.0) and 29 days/cm (IQR 24-43), respectively. The median preoperative mechanical axis deviation (MAD) was 30 mm (IQR 23-39) in the varus cohort and -25 mm (IQR -29 to -15) in the valgus cohort and reduced to a mean of 8 mm (standard deviation [SD] 8) and -3 (SD 10), respectively. Accuracy, precision, and reliability of lengthening were 94%, 95% and 96%, respectively. Accuracy and precision of deformity correction were 92% and 89%, respectively. In total, 40/45 of patients achieved distraction with a difference of less than 1 cm from the initial plan and a postoperative MAD ranging from -10 mm to +15 mm. In 13/45 patients unplanned additional surgeries were conducted to achieve treatment goal with nonunion being the most frequent (4/45) and knee subluxation (3/45) the most severe complication. Acute deformity correction and subsequent lengthening of the distal femur with retrograde ILN is a reliable and accurate treatment achieving treatment goal in 89% but unplanned additional surgeries in 29% of patients should be anticipated.

Low Response Rate to Follow-Up Using Telemedicine after Total Knee Replacement during the COVID-19 Pandemic in Italy.

This study aimed to evaluate the survival rate and medium-term outcomes of patients after cemented posterior-stabilized (PS) mobile-bearing (MB) total knee arthroplasty (TKA) using a telemedicine platform during the COVID-19 pandemic in Italy. A total of 100 consecutive patients (mean age 73.5 ± 13.2 years) who received a cemented PS MB TKA were enrolled. The mean age of patients who did not complete the telemedicine follow-up (58%) was 75.8 ± 9.7 years. A dedicated software that makes it possible to perform video calls, online questionnaires, and acquire X-rays remotely was used. Subjective clinical scores and objective range-of-motion (ROM) measurements were observed at an average follow-up of 54 ± 11.3 months. A total of 42 of 100 enrolled patients (mean age 70.3 ± 8.4 years) completed the telemedicine follow-up. The mean age of patients who did not complete the telemedicine follow-up (58%) was 75.8 ± 9.7 years. Age was found to be a statistically significant difference between the group that completed the telemedicine follow-up and the one that did not (p < 0.004). KOOS scores improved from 56.1 ± 11.3 to 77.4 ± 16.2, VAS scores decreased from 7.2 ± 2.1 to 2.8 ± 1.6, KSSf scores increased from 47.2 ± 13.3 to 77.1 ± 21.1, FJS scores improved from 43.4 ± 12.3 to 76.9 ± 22.9, and OKS scores increased from 31.9 ± 8.8 to 40.4 ± 9.9. All the differences were statistically significant (p < 0.05). The mean flexion improved from 88° ± 8° to 120° ± 12°. A radiographic evaluation showed a mean pre-operative mechanical axis deviation of 5.3 ± 8.0 degrees in varus, which improved to 0.4 ± 3.4 degrees of valgus post-operation. The survivorship at 5 years was 99%. Subject to small numbers, telemedicine presented as a useful instrument for performing remote monitoring after TKA. The most important factor in telemedicine success remains the patient's skill, which is usually age-related, as older patients have much more difficulty in approaching a technological tool.

Genu valgum deformity – correction by a wedgeless implantless femoral “V” osteotomy

Coronal malalignment of the knee joint is very common in developing countries especially because of nutritional rickets. Significant valgus deformity needs to be treated surgically to improve appearance, gait and function of the patient. The purpose of this prospective study was to evaluate the results of supracondylar "V" osteotomy as a surgical technique for correction of the valgus knee deformity. This study was conducted in a tertiary level teaching hospital and 30 cases were included in the study. For all the patients deformity was assessed using ana- tomical tibiofemoral angle, mechanical axis deviation and intermalleolar distance preoperatively and post- operatively. The average age of our patients was 13.7 years and the average follow up was3.29 years (1.39-14.22 yrs). Clinically the average value of intermalleolar distance preoperatively was 16cm and 3.2 cm postperatively. Average pre-operative tibiofemoral angle was 23° and the average postoperative angle was 6 0 which was found to be statistically significant using the Paired t test (p<0.005). The average value of preoperative mechanical axis deviation was 3.1 cm which decreased to an average value of 1.1 cm postoperatively. The results with this technique have been encouraging. The advantages of this technique are low morbidity, good stability allowing early ambulation, ability to adjust alignment postoperatively by casting and no need for internal fixation. Few studies have been conducted on osteotomies that do not require internal fixation and are inherently stable. This technique has the advantage of practically no occurrence of any infection or a second surgery to remove hardware in children and adolescents. Since no specialized instrumentation, image intensifier and implants are required, it is cost effective and can be used in any primary care or district level surgical setup in a developing country like ours.

Correction of Genu Valgum in Patients With Congenital Fibular Deficiency.

Patients with congenital fibular deficiency often develop genu valgum secondary to lateral femoral condylar hypoplasia. Guided growth strategies are often performed to correct limb alignment when adequate skeletal growth remains. A retrospective review of patients with postaxial hypoplasia of the lower extremity managed with an amputation strategy and who had a guided growth procedure for coronal plane limb malalignment during their course of treatment was performed. Clinical and radiographic data, including measures of coronal plane deformity and alignment, type of amputation, subsequent operative procedures, and complications were recorded. Seventeen patients (20 extremities) met study inclusion criteria (mean follow-up 8.8 y). Foot ablation and hemiepiphysiodesis for valgus deformity of the knee was performed in all extremities. The average age at the time of initial hemiepiphysiodesis was 11.2 years at an average of 8.8 years from the initial amputation procedure. The mean preoperative mechanical axis deviation was 26.5 mm, which was corrected to a mean mechanical axis deviation of 7.0 mm. Fifteen (75%) of the extremities had correction of the deformity to neutral alignment after the initial procedure. Lack of correction occurred in 3 extremities, and overcorrection occurred in 2 extremities. Additional procedures were required in 5 extremities for rebound valgus deformity after hardware removal. In patients with postaxial hypoplasia, regular monitoring of the residual limb for growth-related changes must occur to ensure optimal function and prosthetic fit. Timing of the guided growth procedure is critical, as younger patients may be more likely to experience rebound deformity. Families and patients should be made aware that growth might be unpredictable in this population with risks of both overcorrection and undercorrection. Level IV-case series.

Preoperative Supine Radiographs Are More Accurate Than Standing Radiographs for Preoperative Planning in Medial Open-Wedge High Tibial Osteotomy

To verify the accuracy of supine nonweight-bearing radiography versus standing radiography in preoperative planning and to determine the predictors of unintended limb alignment correction in medial open-wedge high tibial osteotomy (OWHTO). Consecutive patients who underwent medial OWHTO for medial osteoarthritis of the knee with varus alignment were retrospectively reviewed. The analyzed pre- and postoperative radiologic measurements included postoperative mechanical axis deviation (MAD) on standing whole-leg radiographs (WLRs), the predicted value of the postoperative MAD on the preoperative supine (predicted MADsupine) radiograph, and standing WLRs (predicted MADstand). Multiple linear regression analysis was used to identify variables predicting the postoperative MAD and unintended MADstand correction, defined as the difference between predicted MADstand and postoperative MAD. Predicted MADsupine showed statistically greater reliability in predicting postoperative MAD than predicted MADstand (intraclass correlation coefficient, 0.82 vs 0.45). Postoperative MAD was correlated with the predicted MADsupine and the difference in hip-knee-ankle angle between preoperative standing and supine WLRs (ΔHKA anglestand-supine) (R=763, R2= 0.582, adjusted R2= 0.569, P < .001) and did not differ significantly from the predicted MADsupine, with a mean difference of 0.28% ± 5.11% (P= .656). The mean unintended MADstand correction was 6.52% ± 8.66%. The difference in preoperative MAD between standing and supine WLRs was a significant predictor for unintended MADstand correction (β= -0.350, P= .004). Preoperative planning with supine WLRs can predict postoperative limbalignment in medial OWHTO more accurately than standing radiographs. The clinical significance of the ΔHKA anglestand-supine for the risk of overestimation of postoperative limb alignment might be low because of the low power in the prediction model and small value of the ΔHKA anglestand-supine. Preoperative soft-tissue laxity was significantly correlated with unintended correction of postoperative limb alignment resulting from preoperative planning with standing radiographs. Level IV, retrospective comparative study.

Recurrence After Surgical Intervention for Infantile Tibia Vara: Assessment of a New Modified Classification.

To propose a modified classification of infantile tibia vara based on the morphology of the metaphyseal/epiphyseal tibial slope that better correlates with treatment outcomes than the traditional Langenskiold classification. We performed a retrospective review of 82 patients and 115 limbs that underwent surgery for infantile tibia vara over a 22-year period (1990 to 2012) at a single institution. A modified Langenskiold classification was applied to all patients preoperatively and the outcomes were assessed. The modified system created a 3-stage classification (types A, B, and C): type A has a partially lucent medial metaphyseal defect, with or without "beaking"; type B deformity has downward-sloping curvature of the lateral and inferior rim of a completely lucent metaphyseal defect, which then has an upslope at the medial rim, resembling a ski-jump, with no epiphyseal downward slope; type C has vertical, downsloping deformity of both the epiphysis and metaphysis, with no upward curvature projecting medially at the inferior extent, while the epiphysis slopes downward into the metaphyseal defect. Sixty-seven limbs did not develop recurrence following corrective osteotomy, whereas 48 limbs required at least 1 repeat surgery for recurrent deformity. Preoperative mechanical axis deviation, medial proximal tibial angle, lateral distal tibial angle, and body mass index did not differ significantly between those with recurrence and those with without. Mean age at surgery was significantly different for those who developed recurrence compared with those who did not. Patients without recurrence were 4.3 years of age (range, 2.4 to 10.3 y) compared with 6.2 years of age (range, 2.9 to 10.1 y) for those who recurred (P<0.01). Of patients who developed recurrent deformity, there were significantly more patients with type C changes (71.7%, P<0.01) then either type A (22.5%) or type B (20.7%). High rates of recurrence were seen for both Langenskiold stage III (50%) and stage IV (69.6%). Consistent with prior studies, age 5 seems to be a critical transition in the risk for recurrent deformity after tibial osteotomy. Extreme vertical sloping of the medial metaphyseal defect, as in some classic Langenskiold III lesions and more precisely described by type C in a newer, modified classification, carries a poor prognosis for successful correction by high tibial osteotomy alone or in combination with epiphysiolysis. Level II.

Simultaneous bilateral correction of genu varum with Smart frame.

The aim of this study is to evaluate clinical and radiological results of simultaneous bilateral correction of genu varum with Smart frame. Between 2011 and 2015, a total of 25 patients (10 females, 15 males) who had bilateral genu varum deformity were operated bilaterally with tibial and fibular osteotomy in the same session, using Smart frame. The mean follow-up period was 28.7 (range, 13-45) months. All patients had bilateral tibial varus deformity. Femoral deformity was corrected in an earlier session in nine patients. Mechanical axis deviation (MAD), mechanical lateral distal femoral angle, mechanical medial proximal tibial angle (mMPTA) and posterior proximal tibial angle (PPTA) were measured preoperatively and postoperatively. Short Form-36 questionnaire was filled by the patients preoperatively and during the last follow-up. The mean preoperative MAD was 37.6 mm (range, 9-98 mm), which improved to 8.4 mm (range, 3-44 mm) postoperatively ( p < 0.05). The mean preoperative mMPTA was 76°, which improved to 89° ( p < 0.05). The mean preoperative PPTA was 75.5°, which improved to 80.3 ( p < 0.05). Ten problems (20%), two obstacles (4%) and no sequelae occurred in 50 legs of 25 patients. In conclusion, Smart frame is an accurate and reliable method for performing bilateral simultaneous deformity correction in patients with bilateral genu varum deformity. It can be applied for various childhood-induced severe tibial deformities such as achondroplasia, rickets, skeletal dysplasia and Blount's disease.

Effectiveness of Treatment for Distal Tibial Nonunions With Associated Complex Deformities Using a Hexapod External Fixator

To determine the efficacy of a hexapod external fixator (TSF) and its ability to perform 6-axis correction in restoring deformities associated with distal tibial nonunions. Consecutive retrospective case review. St. Louis University Hospital. Level 1 Trauma Center. Thirty-seven patients with distal tibial nonunion with greater than 5 degrees of deformity in any plane. Patients were excluded who were less than 18 years of age, had tibial deformities less than 5 degrees, had proximal or middle tibial deformities, or had less than 1 year of follow-up. Patients with distal tibial nonunions with combined deformities were treated by the senior author with a hexapod device. Preoperative mechanical axis deviation and union status were assessed. Postoperative parameters evaluated included anatomic and mechanical axis determination and adequacy of union. Metrics include long alignment films with routine clinical follow-up. Assessment of deformity correction in 6 axes, restoration to union, and mechanical axis correction. Average combined preoperative deformity was greater than 17.7 degrees. Average mechanical axis was restored within 5 degrees of the desired goal in all categories except in patients with severe preoperative valgus deformities. The complex nonunion group had a 94% union rate. Average time in the hexapod was 106.7 days. Average follow-up time was 2 years. Hexapod external fixators can be used as an accurate modality to heal complex distal tibia nonunions with multifocal deformities and significant mechanical axis deviation. These difficult reconstructions are accomplished with minimum complications using these devices. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Evaluation of combined high tibial osteotomy and ‎ilizarov external fixator in the treatment of late-onset tibia ‎var

Purpose The purpose of this study was to evaluate the results of combined high tibial osteotomy in combination with gradual translation by ilizarov external fixator in the treatment of late-onset tibia vara. Patients and methods A total of 23 patients with a diagnosis of late-onset tibia vara, 16 (69.6%) male and seven (30.4%) female, were included in this study; in 14 (60.9%) patients the deformity was on the right side, whereas in nine (39.1%) patients the deformity was on the left side. The etiology was Blount’s disease in all patients. The mean age of the patients was 23 years, ranging from 13 to 35 years, and the mean preoperative mechanical axis deviation was 84.39 mm. The mean preoperative medial posterior tibial angle was 61.17°, whereas the mean preoperative proximal posterior tibial angle was 63.09°. Results The mean duration of external fixator application was 124.6 days, ranging from 90 to 170 days; the mean postoperative medial proximal tibial angle was 86.22°, with a P value of 0.001; the mean postoperative proximal posterior tibial angle was 79.74°, with a P value of 0.001; and the mean postoperative mechanical axis deviation was 10.7 mm, with a P value of 0.001. Residual deformity was present in three (13%) cases, ranging from 5 to 18°; no neurovascular complication was seen in both early and late postoperative periods; and limb length discrepancy was present in five (21.7%) cases, which was between 1.5 and 2.7 cm. Conclusion High tibial osteotomy in combination with gradual correction by ilizarov is safe and effective in the management of late-onset tibia vara.

Can fixator-assisted plating of focal dome osteotomy accurately correct varus deformity in medial compartment osteoarthritis?

Large varus deformities in medial compartment osteoarthritis are difficult to correct with lateral closing-wedge or medial opening-wedge osteotomies. They are easier to correct gradually with opening-wedge or dome osteotomies with external fixation. A focal dome osteotomy can support a large angular correction and yet retains good bony contact. It creates a large proximal fragment that allows for better fixation. However, external fixation devices are cumbersome and not well tolerated by older women and those who cannot follow-up over long distances. Fixator-assisted plating of the focal dome osteotomy combines the advantages of the fixator for accuracy of correction and the convenience of the locking plate. We retrospectively analyzed 34 focal dome high-tibial osteotomies in 31 patients performed over 6 years. Preoperative mechanical axis deviation was −19% (−150%-28%) which improved to 55% (3%-108%). The average preoperative medial proximal tibial angle was 79.8° (88°-63°) which improved to 93° (84°-107°). The average preoperative hip-knee-ankle angle was 195.2° (185°-225°) which improved to 177.5° (166°-204°). Femorotibial angle was 184.6° (182°-220°) which improved to 172° (158°-184°). The tibial slope reduced from 76.9° to 81.1°. Average follow-up was 70 months (45-113). Large varus deformities could be corrected safely with reasonable accuracy in this study.

Does Open Wedge Proximal Tibial Osteotomy Really Affect Tibial Slope and Patellar Height?

Objectives:Open wedge proximal tibial osteotomy has gained popularity over recent years. This technique has several advantages over lateral closed wedge osteotomy, like lack of any need for fibular osteotomy and freedom from peroneal nerve complications, easier and more precise correction, no limb shortening and easier access for an eventual total knee arthroplasty. However it was been shown that open wedge osteotomy may reduce patellar height and increase sagittal tibial slope which can cause patellofemoral problems. The aim of the study was to evaluate the alterations in the angle of posterior slope of the tibia and the degree of patellar height following medial opening wedge proximal tibial osteotomy in our patients.Methods:26 females and 7 males, with a mean age of 48, who underwent medial opening wedge proximal tibial osteotomy were included in the study. In all cases, the preoperative measured varus angle was overcorrected to between 5-8° valgus. The posterior slope of the tibia was determined by the proximal tibial anatomical axis and patellar height was measured retrospectively by the Caton index on the pre- and postoperative radiograms at the end of the second month.Results:Preoperatively, on the standing orthoroentgenograms, the mean mechanical axis deviation was 12,36° (8-20) and the mean posterior tibial slope in the sagittal view was 16,24° (10-23). The mean postoperative tibial slope was 17,85° (6-25). Using paired samples test, this increase was statistically significant (p=0.049). Preoperative mean Caton index was 1,35 (1,01-1,92) and the postoperative average was 1,73 (1,11-2,76). There was also a statistical significant increase between the pre-and postoperative values (p<0.001) with paired samples test. There was a positive correlation between preoperative mechanical axis deviation and postoperative slope angle (p=0,014) but there was no correlation between preoperative mechanical axis deviation and postoperative patellar height.Conclusion:In conclusion, tibial slope and patellar height are strongly affected by open wedge high tibial osteotomy and this might have an adverse effect on an eventual knee arthroplasty.

Hemiepiphysiodesis for Correction of Angular Deformity in Pediatric Amputees

Angular deformities at the knee are common in children with congenital or acquired below-knee or Syme amputations. These deformities can be well compensated and accommodated with prosthetic modifications. However, as children grow, these prosthetic modifications become more difficult and mechanical axis correction becomes necessary. These deformities have previously been treated with osteotomies and internal or external fixation devices, which necessitate prolonged periods without use of their prosthesis. This study examines the results of hemiepiphysiodesis to correct the mechanical axis and improve prosthetic fitting in a pediatric amputee population. Mechanical axis correction using hemiepiphysiodesis in 22 pediatric Symes or transtibial amputees with 22 involved limbs were retrospectively reviewed. Hemiepiphysiodesis was performed with 8-plates (10), staples (6), or drilling and curetting (6). Postoperatively, children were allowed to resume prosthetic use after their wounds healed and they indicated no pain while wearing their prosthesis. Seventeen patients presented with valgus and 5 with varus deformity of their residual limb. Mean age at time of surgery was 11 years and 11 months (range, 7 y and 11 mo to 15 y and 8 mo). Mechanical axis deviation (MAD) was measured before initial surgery and again after hardware removal or physis closure. The mean preoperative MAD was -29.6 mm for the valgus deformities and +10.6 mm for the varus deformities. The mean postoperative MAD was +3.1 mm for the varus knees and -6.0 mm for the valgus knees The mean total mechanical axis correction was 21.8 mm. One patient failed to achieve any mechanical axis correction and 1 hardware failure (broken 8-plate) occurred. Most patients had the staples or 8-plates removed, either after correction was achieved and physes were still open, or due to hardware prominence after physeal closure. Hemiepiphysiodesis provides reliable correction of angular deformity in pediatric amputees. Surgical intervention while skeletally immature allows for correction using guided growth, without the need for osteotomy with internal or external fixation and the resultant disruptions in prosthetic wear. Case Series, Level IV.

Simultaneous management of ipsilateral gonarthritis and extra-articular deformity

Background Total knee arthroplasty (TKA) with extra-articular deformity represents a technical challenge to the reconstructive surgeon. Restoration of proper lower limb alignment is crucial to maximize the functional outcome and long-term implant survival. The current study postulates that simultaneous TKA and deformity correction, whether by intra-articular means or by extra-articular osteotomy, can yield favorable outcomes if the correct surgical strategy is used according to the magnitude and location of the pre-existing extra-articular deformity. Patients and methods The study was carried out on 14 consecutive primary total knee replacements in patients with osteoarthritis secondary to extra-articular malunions. The mean preoperative coronal plane deformity was 14.3 ± 5.2° of varus. The mean preoperative mechanical axis deviation was 8.2 ± 2.1 mm medial to the center of the knee and the mean limb-length discrepancy was 1.8 ± 0.7 cm of shortening. The mean time between malunion and TKA was 29 ± 6.1 years. The results were analyzed using the Knee Society clinical and functional scores and the Knee Society radiographic evaluation system. Results At a mean follow-up of 30.4 months, the mean preoperative Knee Society knee score of 49.7 points improved to a mean of 90.4 points at the time of the latest follow-up (P Conclusion Although isolated TKA with intra-articular deformity compensation and ligamentous balancing may be favored in mild to moderate deformities, there may be faster rehabilitation and functional score gain in the short term after surgery. Yet, simultaneous TKA and extra-articular corrective osteotomy has also yielded favorable outcomes and would still remain the technique of choice in severe deformities (>25°), especially with distant deformities from the knee joint line (diaphyseal, metaphyseodiaphyseal). The closer the deformity to the knee joint line, the more it is amenable to intra-articular correction. Careful preoperative planning is necessary to determine which technique would be better in each particular case.

Correction of Proximal Tibia Varus with External Fixation

Correction of proximal tibia varus deformity has been used with success. Our Protocol is to use monolateral frame to correct varus of less than 10 degrees and to use the Taylor spatial frame for deformities greater than 10 degrees and for multiplanar deformities. Is this protocol successful? Ninety-one limbs in 68 patients with proximal tibia varus were treated with percutaneous proximal tibial osteotomy and external fixation. The monolateral and spatial frames were used for 36 and 55 limbs, respectively. Each group was further subdivided into neutral or intentionally overcorrected subgroups. Monolateral group time of correction and time in frame was 15 days (8 to 20) and 101 days (81 to 133), respectively. The preoperative mechanical axis deviation (MAD) was 22 mm medial (10 to 44). Postoperative MAD in the neutral subgroup was 5 mm lateral (2 to 10) and 3 mm medial (0 to 7). Postoperative MAD in the overcorrected subgroup was 10 mm lateral (4 to 20) and one patient was 5 mm medial. Medial proximal tibial angle (MPTA) improved from 85 degrees (79 to 89) to 90 degrees (85 to 96) in the neutral group and to 92 degrees (85 to 98) in the overcorrected group. Spatial frame group time of correction and time in frame was 34 days (7 to 99) and 130 days (95 to 177), respectively. The preoperative MAD was 40 mm medial (range 5 to 155). This improved to 5 mm medial (0 to 30) and 4 mm lateral (0 to 7) in the neutral group, and 17 mm medial (0 to 35) and 11 mm lateral (4 to 28) in the overcorrection group. MPTA improved from 80 degrees (40 to 87) to 88 degrees (83 to 96) in the neutral group and to 84 degrees (89 to 97) in the overcorrected group. In both groups, there was no significant change in the ankle or knee range of motion. There was one refracture in both groups. Our algorithm for treating proximal tibial varus deformities is safe and effective. For simple varus deformities, we recommend use of the monolateral frame. We reserve the use of the spatial frame for large or complex deformity correction.

Total Knee Arthroplasty with Use of Computer-Assisted Navigation Compared with Conventional Guiding Systems in the Same Patient: Radiographic Results in Asian Patients

The value of computer-assisted surgery in total knee arthroplasty for arthritic knees continues to be debated. We hypothesized that the usefulness of computer assistance is related to the magnitude of the deviation from the preoperative mechanical axis and that computer-assisted surgery may be beneficial under certain circumstances. Patients with bilateral knee osteoarthritis and genu varus deformity who were to have staged bilateral total knee arthroplasty were enrolled. The patients randomly underwent computer-assisted total knee arthroplasty in one knee and conventional total knee arthroplasty in the contralateral knee. The two methods were compared for accuracy of placement of the components and lower extremity alignment after total knee arthroplasty as determined by six radiographic parameters. One hundred and thirteen patients (226 knees) met the inclusion criteria. For patients with a preoperative mechanical axis deviation of <10° and those with a deviation of 10° to 14.9° in both knees, the postoperative radiographic parameters did not differ significantly between the two techniques. In patients with a preoperative mechanical axis deviation of >20°, the reconstructed mechanical axes were significantly closer to normal in the computer-assisted total knee arthroplasty group. Significant results were also noted in the anatomical axes, femoral valgus angle, and femoral flexion angle. Furthermore, a higher percentage of knees in which computer-assisted surgery was used had restoration of the mechanical axis within 3° of neutral. Computer-assisted surgery was a valuable adjunct for obtaining proper alignment during total knee arthroplasty in patients with knee osteoarthritis with severe varus deformity. Conventional total knee arthroplasty was as effective as computer-assisted total knee arthroplasty for obtaining proper alignment in patients with a minor to moderate deformity.

Is Correctional Osteotomy Crucial in Primary Varus Knees Undergoing Anterior Cruciate Ligament Reconstruction?

Valgus high tibial osteotomy (HTO) has been recommended for ligament stability and enhanced function after anterior cruciate ligament (ACL) reconstruction in varus-angulated knees. However, it is not clear whether HTO should be performed in patients undergoing ACL reconstruction who have primary varus knees without medial compartment arthrosis. We therefore asked whether stability and function differed in patients having ACL reconstruction with differing degrees of preoperative alignment. We retrospectively reviewed 201 patients who had primary, single-bundle ACL reconstructions with primary varus knees based on the preoperative mechanical axis deviation (MAD) on preoperative standing hip-knee-ankle radiographs. Patients were categorized into four groups according to the MAD: Group 1: 0 mm to 4 mm, Group 2: 5 mm to 9 mm, Group 3: 10 mm to 14 mm, and Group 4: greater than 15 mm. A total of 201 patients, 67 in Group 1, 53 in Group 2, 38 in Group 3, and 43 in Group 4, were assessed. Ligament stability was determined with the Lachman test, pivot shift test, and KT 2000™ arthrometer. Functional scores were assessed using the Lysholm score and the International Knee Documentation Committee (IKDC) score. The minimum followup was 24 months (mean, 45 months; range, 24-96 months). We observed no differences in the side-to-side KT 2000™ measurements, Lysholm score, or IKDC functional scores based on the preoperative MAD. The stability and functional scores after ACL reconstruction were not adversely altered by primary varus alignment. Thus, if there is no medial compartment arthritis or varus thrust, we do not believe a correctional tibial osteotomy is crucial in primary varus knees undergoing ACL reconstruction.

Correction of post-traumatic lower limb deformities using the Taylor spatial frame

Twenty-five post-traumatic leg length discrepancies combined with axial deviation in 22 patients were treated with the Taylor spatial frame. We retrospectively analysed the accuracy of correction, the complication rate and the clinical outcome including the duration of treatment. The cases were divided into three sub-groups according to the level of the osteotomy. The mean age at operation was 22.7 years; the mean follow-up was 21.1 months. The patients presented uniplanar and multiplanar deformities in combination with leg length discrepancy. Twenty-one of 25 cases showed a frontal plane malalignment preoperatively. Only three of those 21 cases continued to show minimal malalignment postoperatively. The preoperative mechanical axis deviation present in 15 of 17 lower extremities was fully corrected in 13 extremities. The 25 lengthening and correction procedures were associated with a total of 61 difficulties, including 44 problems, seven obstacles and ten complications. In conclusion, the Taylor spatial frame allows accurate results in correction of complex post-traumatic deformities with minimal morbidity.

Fixator-Assisted Acute Femoral Deformity Correction and Consecutive Lengthening Over an Intramedullary Nail

External fixators are being used frequently in standard limb-lengthening and deformity-correction procedures. Lengthening over an intramedullary nail has been a successful technique, and fixator-assisted intramedullary nailing has provided satisfactory results for the correction of selected deformities. We report a combined technique for the treatment of femoral deformities associated with shortening. Between 1997 and 2005, twenty-eight femora in twenty-five patients with a median age of twenty-seven years underwent reconstruction with an intramedullary nail and a unilateral fixator. The mean amount of shortening was 6.33 cm, and the mean preoperative mechanical axis deviation was 33.86 mm. Deformity correction was performed acutely and secured by the intramedullary nail, which was locked distally, and the same external fixator that was used for the deformity correction was utilized for lengthening. At the end of the distraction period, proximal locking screws were placed in the intramedullary nail and the external fixator was removed. At the time of follow-up, deformity correction and bone healing were assessed clinically and radiographically, complications were noted, and the functional results were assessed. The mean duration of follow-up was forty months. The mean duration of the external fixation was 83.29 days, and the mean external fixation index was 14.98 days/cm. The mean amount of lengthening was 6.02 cm. The mean amount of mechanical axis deviation at the end of the treatment was 11.29 mm. The mean bone healing index was 36.66 days/cm. A knee flexion contracture developed in one patient and resolved after intensive rehabilitation. One patient underwent two revisions because of Schanz screw displacement secondary to cortical fracture, and four patients with minor pin-track infections were treated successfully with local wound care and oral antibiotics. While femoral lengthening and deformity correction can be obtained with classic methods for application of an external fixator, the long period of external fixation, patient discomfort, and plastic deformation of the regenerated bone after removal of the fixator are major disadvantages. Two techniques, fixator-assisted nailing and lengthening over an intramedullary nail, were combined in this series. The duration of the external fixation was reduced compared with that required for classic treatment with an external fixator and patient comfort was increased. In addition, the intramedullary nail prevented fracture and deformation of the regenerated bone.

Accuracy of Correction of Complex Lower-Extremity Deformities by the Ilizarov Method

Gradual mechanical distraction with the Ilizarov external fixator was used on 28 limbs in 23 patients to correct complex lower-extremity deformities of diverse causes. To determine the accuracy of realignment and deformity correction, the charts and radiographs were reviewed retrospectively. Preoperative long-standing anteroposterior radiographs of the entire lower extremity were compared with those obtained at the most recent follow-up visit. The parameters used to assess accuracy of correction were joint alignment and joint orientation. Alignment was determined by mechanical axis deviation (MAD) and mechanical tibiofemoral angle (mTFA). The preoperative MAD averaged 48 mm and the postoperative MAD 8.6 mm. The preoperative mTFA averaged 16 degrees and the postoperative mTFA 3 degrees. The result of deformity correction from early cases was compared with the result obtained from recent cases. Residual MAD averaged 13.2 mm in the early group and 6.4 mm in the recent group. Residual mTFA averaged 4.7 degrees in the early group and 2.2 degrees in the recent group. Gradual correction by dynamic external fixation can restore alignment and correct complex deformities with great accuracy. These results suggest the accuracy of correction increases with surgical experience.