Proximal tibial varus osteotomy. Indications, technique, and five to twenty-one-year results

BACKGROUND: Although high tibial osteotomy has been proved effective for the treatment of painful osteoarthritis of the medial compartment of the knee, the role of proximal tibial varus osteotomy for the treatment of painful osteoarthritis of the lateral compartment still remains controversial. METHODS: From 1974 to 1993, we performed proximal tibial varus osteotomy for the treatment of osteoarthritis of the lateral compartment of the knee in thirty-six consecutive patients. The procedure consisted of a proximal lateral opening-wedge varus osteotomy of the tibia with use of corticocancellous bone grafts from the iliac crest. The valgus deformity was posttraumatic in twenty-three patients, followed a lateral meniscectomy in five, was due to overcorrection of a varus deformity in four, and was idiopathic in four. The preoperative valgus deformity averaged 11.6 degrees (range, 4 degrees to 22 degrees ). RESULTS: At a mean of eleven years (range, five to twenty-one years) after the operation, the clinical results for thirty-four of the thirty-six patients were analyzed. None of the patients had severe progression of the osteoarthritis after the osteotomy, and none had a meaningful loss in the range of motion of the knee joint. A superficial wound infection developed in one patient, and another patient had thrombophlebitis. Three patients (9%) had a transient palsy of the peroneal nerve. According to the system of Insall et al., the mean knee score was 84 points (range, 54 to 99 points). According to the knee score described by Lysholm and Gillquist, the subjective result was excellent in nine patients (26%), good in twenty-one (62%), fair in three (9%), and poor in one (3%). CONCLUSIONS: We concluded that when the indications outlined in this study are followed and our opening-wedge technique is used, a proximal lateral opening-wedge varus osteotomy of the tibia is a good alternative for the treatment of isolated osteoarthritis of the lateral compartment of the knee. High accuracy in preoperative planning, based on a slight overcorrection, is important to prevent failure.     

中老年女性骨关节炎患者骨密度的特点

目的　通过测量骨关节炎患者腰椎和髋部骨密度 ,探讨骨关节炎患者骨密度的特点及骨关节炎与骨质疏松症的关系。方法　本组研究对象均为中老年女性膝关节骨关节炎患者 ,其中 5 9例测量了腰椎和髋部骨密度 ,12例仅测量了腰椎骨密度。所有患者均按Kellgren分级标准对膝关节进行了评分。结果　绝经后妇女膝关节X线评分随Kellgren分级级数的增高患者腰椎骨密度均值逐渐增高 ,4级骨关节炎患者腰椎骨密度均值明显高于 2级患者 (P <0 0 5 ) ,而髋部骨密度均值随Kellgren分级级数的增高差异无显著性。如以低于同性别同部位峰值骨量的 2 0SD为骨质疏松诊断标准 ,腰椎和髋部符合骨质疏松症诊断的分别为 4 3 7%和 77%。在控制年龄和骨关节炎的影响后 ,股骨颈骨密度与体重指数的偏相关系数为 0 4 0 7(P <0 0 1)。结论　中老年女性骨关节炎患者中同时患有骨质疏松症的比例较高 ,同髋部骨密度测量相比 ,腰椎骨密度测量受骨关节炎影响较大。     

Proximal tibial varus osteotomy for osteoarthritis of the lateral compartment of the knee

From 1960 through 1979, a closing-wedge varus osteotomy of the proximal part of the tibia was performed in thirty-one knees (twenty-eight patients) for painful osteoarthritis of the lateral compartment of the knee that was associated with a valgus deformity. The patients were followed for two to seventeen years (average, 9.4 years). Twenty-four knees (77 per cent) had either no pain or only occasional mild pain at the last evaluation. Six knees had moderate pain and one, severe pain. Six knees required a subsequent total knee arthroplasty at an average of 9.8 years after the osteotomy. No patient had an infection or non-union. Osteotomy of the proximal part of the tibia is a reasonable method of treating unicompartmental degenerative arthritis in a knee with a valgus deformity. Although some patients with as much as 20 degrees of anatomical valgus deformity obtained a good result in this series, osteotomy in the supracondylar region of the femur is probably preferable if the valgus angulation exceeds 12 degrees or if the tilt of the tibial articular surface that will result from the surgery will exceed 10 degrees. Correction beyond the normal 5 to 7 degrees of valgus angulation to zero degree of anatomical tibiofemoral alignment is recommended to prevent recurrence of the valgus deformity and to decrease the load on the lateral tibiofemoral compartment.     

Bone mineral distribution of the proximal tibia in gonarthrosis assessed in vivo by photon absorption

Regional bone mineral density (BMD, g/cm2) of the proximal tibia including the subchondral plate was measured in vivo by dual photon absorptiometry (DPA). Twenty-one women and six men with gonarthrosis (GA) were examined. Twenty-four healthy women served as controls for the women. The precision error of the BMD measurements ranged from 1.4-3.7% depending on the region measured. Subchondral BMD correlated significantly to the radiologic stage (P < 0.05). Compared to the controls, BMD of the subchondral plate, BMD of the medial condyle, the medial to lateral distribution ratio of subchondral BMD and the ratio between BMD of the subchondral plate and of the immediately underlying region were significantly increased in patients with predominantly medial GA (P < 0.05-0.0001). The BMD of the lateral condyle was lower in GA patients than in controls (P < 0.05). In patients with unilateral GA, the above-mentioned changes were found in the affected tibia compared to the normal knee in the same individual (P < 0.05). In contrast to any of the patients with varus deformity, the two patients with valgus deformity had higher BMD of the lateral condyle than of the medial. No differences in BMD of the distal forearm or the ultradistal region of the proximal tibia were found between the GA patients and the controls. The study shows that regional bone changes of the proximal tibia in GA can be measured precisely and noninvasively in vivo by DPA.     

Infantile tibia vara: Treatment of Langenskiold stage IV

An eight year old girl presented with a progressively increasing deformity of the left proximal tibia since last 2 years. She had no history of trauma, fever and swelling of left knee. There were no obvious signs of rickets/muscular dystrophy. She had 25 degrees of tibia vara clinically with lateral thrust and a prominent fibular head. The radiograph of left knee revealed tibia vara with medial beaking and a significant depression of the medial tibial epiphysis and metaphysis. A computed tomography (CT) scan revealed significant depression of the medial tibial epiphysis but no bony bar in the physis or fusion of the medical tibial epiphysis. There was a posterior slope in addition to the medial one. She was treated with elevation of the medial tibial hemiplateau with subtuberosity valgus derotation dome osteotomy. She also underwent a lateral proximal tibial hemiphysiodesis (temporary stapling). A prophylactic subcutaneons anterolateral compartment fasciotomy was also performed. All osteotomies united in 2 months. All deformities were corrected and she regained a knee range of 0 to 130 degrees. At final followup (4 years), there was no recurrence of varus deformity, knee was stable, with 1cm of leg length discrepancy. In Langenskiold stage IV tibia vara, elevation of medial tibial plateau, a subtuberosity valgus derotation osteotomy and a concomitant lateral hemiephiphysiodesis has given good results.     

In vitro strain distribution in the proximal tibia. Effect of varus-valgus loading in the normal and osteoarthritic knee

Six human cadaver legs were tested with strain-gauge rosettes to determine the effects of varus/valgus loading on the distribution of strain on the cortical bone of the proximal tibia at loads of up to 250 kg. Changes in the femorotibial angle of 1.5 degrees and 3.1 degrees, to create varus/valgus deformities, produced significant unloading of the opposite aspect of the normal leg. A varus deformity of 3.1 degrees in the medial compartment osteoarthritic model virtually unloaded the lateral compartment and, because of the bending effect, placed the whole of the lateral aspect of the leg into axial tension. Under these conditions, the axial strains in almost the whole of the medial aspect of the tibia were doubled, from an initial value of 250 microstrain (compressive) to a value of approximately 500 microstrain (compressive). While a change in load-action, to simulate a 3.1 degrees valgus deformity in the medial compartment osteoarthritic model, did not completely unload the medial plateau of the tibia, it was suggested that such unloading could be achieved with slightly greater valgus loading. Successful clinical results, employing valgus osteotomies in patients with medial compartment osteoarthritis, are obtained by unloading the medial compartment while markedly increasing compressive loads on the whole of the lateral aspect of the leg.     

Recurrent knee valgus deformity in Ellis-van Creveld syndrome

We report a case of recurrent knee valgus deformity in a patient with Ellis-van Creveld syndrome. Varus osteotomy, distraction osteogenesis, or epiphyseal stapling is one treatment option for valgus malalignment to improve appearance, gait, and function. However, surgical correction of valgus knee deformity by varus osteotomies of the proximal tibia was not maintained postoperatively, necessitating additional varus osteotomies of the distal femur in this case. The main cause of recurrence was attributed to large bony defect of the anterior segment of the proximal tibia, in addition to depression of the lateral tibial plateau.     

The Functional Status of the ACL in Varus OA of the Knee: The Association With Varus Deformity and Coronal Tibiofemoral Subluxation

BackgroundThe present article analyzes the association of the functional anterior cruciate ligament (ACL) status and the overall varus deformity and coronal tibiofemoral subluxation (CTFS) in varus OA of the knee.MethodsOne hundred consecutive knees with varus OA in 84 patients were prospectively included. Knees were divided into two groups, in accordance with the ACL status (functionally sufficient or insufficient). All included patients were potential candidates for unicompartmental knee arthroplasty with predominantly medial compartment OA. Knees with Kellgren/Lawrence ≥ grade 3 in the lateral compartment were excluded leaving 79 knees to be included in this study. Mechanical varus deformity and CTFS were evaluated on AP radiographs and valgus stress radiographs, and compared between the two groups.ResultsKnees with a functionally insufficient ACL had significantly more varus deformity on hip-to-ankle AP standing radiographs (P = .001) and on valgus stress radiographs (P = .017). CTFS on AP standing radiographs was significantly higher (P = .045) in knees with a functionally insufficient ACL. Seventy-three percent (8/11) of the ACL-insufficient knees had a varus deformity of ≥10° and 64% (7/11) of ACL-insufficient knees had CTFS ≥ 6mm. By contrast, only one patient (2%, 1/41) with an insufficient ACL had< 10° varus deformity and a CTFS of < 6mm.ConclusionFunctional ACL insufficiency in osteoarthritic varus knees is associated with greater varus deformity and more advanced CTFS. Seventy-three percent of ACL-insufficient knees had a varus deformity of ≥10° and 64% of ACL-insufficient knees a CTFS of ≥ 6mm. In the work-up for medial unicompartmental knee arthroplasty, functional ACL insufficiency is likely in knees with varus deformity of ≥10° and CTFS of ≥ 6mm.     

Femoral deformity in tibia vara

BACKGROUND: Previous studies have suggested that compensatory valgus deformity of the femur is common in patients with tibia vara, or Blount disease. The availability and routine use of standing long-cassette radiographs of the lower extremities to assess angular deformities has allowed quantitative evaluation of this hypothesis. METHODS: The cases of all patients with tibia vara, two years of age or older, seen at our institution prior to treatment, over a thirteen-year period, were reviewed. Seventy-three patients with a total of 109 involved lower limbs were identified and were classified as having either infantile tibia vara (thirty-seven patients with fifty-six involved limbs) or late-onset tibia vara (thirty-six patients with fifty-three involved limbs). Standardized standing radiographs of the lower extremity were examined to assess the deformity at the distal part of the femur and the proximal part of the tibia by measuring the lateral distal femoral angle and the medial proximal tibial angle. RESULTS: The distal part of the femur in the children with infantile tibia vara either was normal or had mild varus deformity, with a mean lateral distal femoral angle of 97 degrees (range, 82 degrees to 129 degrees). The mean medial proximal tibial angle in these children was 72 degrees (range, 32 degrees to 84 degrees). Older children with infantile tibia vara were noted to have little distal femoral deformity, with no more than 4 degrees of valgus compared with either normal values or the contralateral, normal limb. Children with late-onset tibia vara had a mean lateral distal femoral angle of 93 degrees (range, 82 degrees to 110 degrees) and a mean medial proximal tibial angle of 73 degrees (range, 52 degrees to 84 degrees). On the average, the varus deformity of the distal part of the femur constituted 30% (6 degrees of 20 degrees) of the genu varum deformity in these patients. CONCLUSIONS: Patients with infantile tibia vara most commonly had normal alignment of the distal parts of the femora; substantial valgus deformity was not observed. Distal femoral varus constituted a substantial portion of the genu varum in children with late-onset disease. When correction of late-onset tibia vara is planned, the surgeon should be aware of the possibility that distal femoral varus is a substantial component of the deformity.     

Varus Gonarthrosis Predisposes to Varus Malalignment in TKA

Postoperative alignment is a predictor for long-term survival of total knee arthroplasty (TKA). The purpose of this study was to evaluate whether or not preoperative deformities predispose to intraoperative malposition of TKA components. A retrospective radiographic analysis of 53 primary TKA cases was performed. Preoperative AP hip to ankle and lateral knee radiographs were compared with postoperative views to evaluate component positioning. The following angles were measured: the hip–knee–ankle (HKA) angle expressing the mechanical axis of the leg, the mechanical lateral distal femur angle (mLDFA), the medial proximal tibia angle (MPTA), the posterior distal femur angle (PDFA), and the posterior proximal tibia angle (PPTA). Postoperative measurement of the HKA revealed 34.0% of the cases had a deviation of >±3° from neutral alignment. Sixteen knees (30.2%) were in varus and, with one exception, all presented with severe varus gonarthrosis prior to surgery with a mean tibiofemoral angle of 12.4° compared with 1.0° of valgus in the optimally aligned group. Patients (93.3%) with preoperative valgus malalignment showed optimal postoperative HKA. Odds ratios for malalignment of TKA for varus knees in comparison with valgus knees were 7.1 for HKA, 2.4 for MPTA, 4.9 for PDFA, and 1.7 for PPTA. The overall number of outliers in the presented data corresponds well with reports from other authors using different implants and guide systems. The presented data indicate that patients with preoperative varus alignment have a higher risk of postoperative implant malposition than patients with valgus alignment. The data supports that preoperative varus deformity predisposes to varus malposition of TKA. The risk for intraoperative malposition is significantly lower in valgus knees.     

膝骨关节炎病因、X线片及临床表现分析

目的探讨国人膝骨关节炎病因,临床表现和Ｘ线片的相关性,为临床诊治提供依据。方法对骨科门诊膝骨关节炎患者进行病因,临床表现调查,摄单腿站立位膝关节正侧位、髌骨轴位片,分析Ｘ线征象并作骨关节炎分级、分型。结果膝骨关节炎原发性占８７％,继发性占１３％,膝骨关节炎分型：初期型３８％,股型２８．５％,内侧－髌股型２３．２％。随关节炎分类程度的加重,稞症状向严重发展（Ｐ〈０．０１）。胫股角越大,Ｘ线分级趋向病     

Is end-stage lateral osteoarthritic knee always valgus? Mechanical alignment analysis and radiographic severity assessment

Background

We hypothesized that not all persons with end-stage lateral osteoarthritis (OA) have valgus malalignment and that full extension radiographs may underreport radiographic disease severity. The purpose of this study was to examine the demographic and radiographic features of end-stage lateral compartment knee OA.

Materials and methods

We retrospectively studied 133 knees in 113 patients who had undergone total knee arthroplasty between June 2008 and August 2010. All patients had predominantly lateral idiopathic compartment OA according to the compartment-specific Kellgren–Lawrence grade (KLG). The mechanical axis angle (MAA), compartment-specific KLG and joint space narrowing (JSN) of the tibiofemoral joint at extension and 30° of knee flexion, tibia vara angle, tibial slope angle, body mass index, age, and sex were surveyed.

Results

End-stage lateral compartment knee OA has varus (37.6 %), neutral (22.6 %), and valgus (39.8 %) MAA on both-leg standing hip-knee-ankle radiographs. KLGs at 30° of knee flexion (fKLG) were grades 3 and 4 in all patients. However, for KLGs at full extension (eKLG), 54 % of all patients had grades 3 and 4. The others (46 %) showed grades 1 and 2. We observed significant differences in lateral compartment eKLG/eJSN (2.3/2.3 mm in varus, 2.5/1.9 mm in neutral, 2.9/1.6 mm in valgus, p = 0.01 and 0.03, respectively), tibia vara angle (4.9° in varus, 4.1° in neutral, 3.0° in valgus, p < 0.01), and medial compartment eKLG/eJSN (2.1/3.1 mm in varus, 2.0/3.4 mm in neutral, 1.8/4.3 mm in valgus, p < 0.01 and 0.01, respectively) between MAA groups, except for the tibial slope angle (9.7° in varus, 10.1° in neutral, 9.8° in valgus, p = 0.31).

Conclusion

Varus alignment was paradoxically shown in approximately one-third of those with end-stage lateral knee OA on both-leg standing hip-knee-ankle radiographs. Films taken in full extension underreported the degree of OA radiographic severity.

Level of evidence

Level IV, observational study.

     

Comprehensive treatment of late-onset tibia vara

BACKGROUND: Late-onset tibia vara (Blount disease) can be difficult to treat because of frequent morbid obesity and associated deformities, including distal femoral varus, proximal tibial procurvatum, and distal tibial valgus, that contribute to lower extremity malalignment. We present a comprehensive approach that addresses all components of the deformity and allows restoration of the anatomic and mechanical axes. METHODS: Fifteen consecutive patients (nineteen lower extremities) with late-onset tibia vara were managed with this comprehensive approach. The mean age of the patients at the time of surgery was 14.9 years, and the mean weight was 113 kg. Standing anteroposterior and lateral radiographs were made preoperatively and at the time of the final follow-up. Preoperatively, the mean mechanical axis deviation was 108 mm, the mean lateral distal femoral angle was 95 degrees , and the mean mechanical medial proximal tibial angle was 71 degrees . In all nineteen extremities, the proximal tibial varus deformity was corrected by means of a valgus osteotomy and application of an Ilizarov ring external fixator. Distal femoral varus was corrected by means of either hemiepiphyseal stapling or valgus osteotomy with blade-plate fixation in thirteen of the nineteen extremities. Distal tibial valgus was treated either with hemiepiphyseal stapling or with varus osteotomy and gradual correction with use of the Ilizarov external fixator in eleven of the nineteen extremities. RESULTS: After a mean duration of follow-up of 5.0 years, the mean mechanical axis deviation had improved to 1 mm (range, 20 to -30 mm), the lateral distal femoral angle had improved to 87 degrees (range, 83 degrees to 98 degrees), and the mechanical medial proximal tibial angle had improved to 88 degrees (range, 83 degrees to 98 degrees ). The mean time required for correction of the proximal tibial varus deformity was thirty-one days, and the external fixator was removed at a mean of 4.5 months postoperatively. All patients had development of one or more superficial pin-track infections (mean, 1.9 pin-site infections per patient). No wound infections, nonunions, or neurovascular complications occurred. Eighteen of the nineteen extremities were pain-free at the time of the final follow-up. CONCLUSIONS: This comprehensive approach allowed restoration of the mechanical and anatomic axes of the lower extremity in patients with late-onset tibia vara, resulting in a resolution of symptoms as a result of normalization of the weight-bearing forces across the knee and ankle. We believe that this approach will decrease the risk of early degenerative arthritis of the knee.     

Tibial condylar valgus osteotomy (TCVO): Surgical technique and clinical results for knee osteoarthritis with varus deformity

Tibial condylar valgus osteotomy (TCVO) is an intra-articular proximal tibial osteotomy developed in 1989 and has since been used for the treatment of knee osteoarthritis (OA) associated with genu varum. This article describes the surgical technique and clinical results of TCVO. TCVO can be used for all grades of varus knee OA in patients of any age. he preoperative range of movement should be at least 90°. Preoperative screening showed varus-valgus instability due to an intra-articular deformity of the proximal tibia. Using intraoperative image intensification, a sagittally oriented “L”-shaped osteotomy is made from the medial to the tibial tuberosity to the center of the tibial plateau between the medial and lateral tibial spines. The separation of the osteotomy using the lamina spreader is gradually increased using an image intensifier guidance until the articular surface of the lateral tibial plateau comes in contact with the articular surface of the lateral femoral condyle. Adequate correction is indicated by parallelism of the lateral tibial plateau and a line tangential to the distal convexity of the lateral femoral condyle on an anteroposterior (AP) image and the elimination of the valgus instability with the knee in extended position. A “T”-plate (locking or non-locking plate or circular external fixator) is used to fix the osteotomy in the corrected position. Synthetic or autologous bone grafts can be used. We used the Japanese Orthopaedic Association score to evaluate the patient's function and also measured the %MAD, medial plateau opening angle, medial plateau angle, and lateral plateau opening angle on an AP view of the long length roentgenogram of the lower limb (standing position). The JOA score, radiologically measured values, and instability of the knee joint remarkably improved.     

Arthroplasty in treating knee osteoarthritis and proximal tibia stress fracture

The authors describe two cases of severely angulated tibial non-unions after proximal tibia stress fractures associated with ipsilateral osteoarthritis treated with modular knee endoprosthesis with a long tibial stem to stabilize non-union fragments. During the procedure, no additional osteosynthesis or bone grafting was added. Both non-unions healed after 6 months with no post-operative complications. The authors suggest implantation of modular knee endoprosthesis, as a single procedure, in treatment of proximal tibia non-union after a stress fracture as a result of severe varus/valgus deformity. It provides a solution for osteoarthritis treatment, axis correction and non-union osteosynthesis.     

Distal femoral osteotomy for valgus deformity of the knee.

Distal femoral varus osteotomy and blade-plate fixation for valgus deformity of the knee proved effective in restoring axial alignment in 18 of 36 knees (34 patients). Patients were followed for an average of 5.4 years (range: 2 to 19 years). The osteotomies were performed on 14 men and 22 women (average age: 44 years; range: 14 to 77). The patients' average preoperative valgus deformity of the anatomical axis was 19.4 degrees (range: 8 degrees to 33 degrees). The surgical procedures performed were a medial closing wedge osteotomy (14 knees) and a lateral opening wedge osteotomy with bone grafting (22 knees). Postoperative correction of the anatomical axis averaged 3.8 degrees valgus (range: 8 degrees varus to 20 degrees valgus). Maximum improvement was reached within 6.3 months by patients who were less than 60 years old and within 5.1 months by patients who were more than 60 years old. Pain decreased or resolved in 21 of 35 knees (60%); activity level improved in 24 of 35 knees (69%). One patient was unavailable for follow up evaluation. Varus osteotomy in the distal femur was concluded to be an acceptable form of treatment in the valgus knee alone or associated with traumatic or osteoarthritis of the lateral compartment.     

Percutaneous epiphyseodesis. Correction of leg length inequalities and frontal plane deformities

The percutaneous epiphysiodesis is recommended as a save and reliable technique. We have performed 21 distal femoral, 17 proximal tibial and 3 proximal fibular percutaneous epiphyseodeses on 25 patients. On 11 patients the epiphysiodesis was caused by an average leg length discrepancy of 2,7 cm (1-4 cm). 13 patients had angular deformity near the knee joint in frontal plane (6 valgus and 7 varus deformities). One patient suffered from a combined deformity with 3, 5 cm shortened leg and varus deviation of 10 degrees. The average deformity angle of the knee was 7,4 degrees (4 degrees -16 degrees ). 9 patients have reached maturity. On 3 patients the deformity could be corrected incompletely with residual deformity of 3 degrees, 4 degrees and 6 degrees as a direct result of late referral. On 1 patient an imminent over-correction could be avoided by hemiepiphysiodesis of the residual epiphysis. Till the present follow up the other patients have been corrected as calculated preoperatively. No complications like epiphysiolysis, infection, stiff knee or angular deformities occurred. We prefer the percutaneous epiphysiodesis as a save and minimal invasive technique instead of the open Phemister-technique to tread leg length discrepancy and angular deformities of the knee in frontal plane.     

Periprosthetic tibial bone mineral density changes after total knee arthroplasty: one-year follow-up study of 69 patients

BACKGROUND: The critical structure supporting the prosthetic components in total knee arthroplasty (TKA) is tibial trabecular bone. The quality of tibial bone can be evaluated by bone mineral density (BMD) measurements. PATIENTS AND METHODS: We prospectively measured changes in BMD in the proximal tibia after cemented TKA in osteoarthrotic knees. 69 patients were scanned by dual-energy X-ray absorptiometry (DXA) within a week after surgery, and after 3, 6 and 12 months. RESULTS: At baseline, the medial region of interest (ROI) BMD was higher in the varus knees than in the valgus aligned knees (p=0.02). The medial metaphyseal ROI showed a decrease in BMD during the follow-up in preoperatively varus knee joints (p<0.001). In preoperatively valgus knees, there was a slight increase in medial compartment BMD which was not significant (p=0.2). Alignment correction in both groups showed bone remodeling giving similar medial and lateral BMD values, suggesting that the bone became equally strong in both compartments of the metaphysis. There was no association between increasing American Knee Society (AKS) scores and bone remodeling. INTERPRETATION: We suggest that this remodeling is caused by postoperative changes in tibial loading. Our results support the clinical importance of recreating proper valgus alignment of the knee joint in the TKA operation, thus possibly providing better conditions for longevity of the tibial component.     

Anatomical analysis of the femoral condyle in normal and osteoarthritic knees.

It is important to understand anatomical feature of the distal femoral condyle for treatment of osteoarthritic knees. Detailed measurement of the femoral condyle geometry, however, has not been available in osteoarthritic knees including valgus deformity. This study evaluated femoral condyle geometry in 30 normal knees, 30 osteoarthritic knees with varus deformity, and 30 osteoarthritic knees with valgus deformity using radiographs and magnetic resonance imaging (MRI). In radiographic analysis in the coronal plane, the femoral joint angle (lateral angle between the femoral anatomic axis and a tangent to femoral condyles) was 83.3 degrees in the normal knees, 83.8 degrees in the varus knees, and 80.7 degrees in the valgus knees. In MRI analysis in the axial plane, the posterior condylar tangent showed 6.4 degrees of internal rotation relative to the transepicondylar axis in the normal knees, 6.1 degrees in the varus knees, and 11.5 degrees in the valgus knees. These results suggested that there was no hypoplasia of the medial condyle in the varus knees, but the lateral condyle in the valgus knees was severely distorted. Surgeons should take this deformity of the lateral femoral condyle into account when total knee arthroplasty is performed for a valgus knee.     

Multiple osteocartilaginous exostosis

Deformity of the lower extremities in 26 patients with multiple cartilaginous exostosis was examined radiologically. Follow-up periods ranged between 3 and 33 years (mean 10.3 years). Twenty-four patients had deformity of the joints. A femoral neck-shaft angle (FNA) of more than 150° was noted in 14 patients (26 of 51 hip joints) at diagnosis. After approximately 10 years of age, the FNA tended to decrease. Eleven patients (22 of 52 knee joints) had genu valgum (the femorotibial angle < mean –2 SD of normal control) which was caused by valgus deformity of the distal femur in one-third of the patients and that of the proximal tibia in two-thirds. Fifteen of 21 patients (29 of 42 joints) had valgus deformity of the ankle (antero-posterior mortise angle of the ankle > 94^c), and in half of them, the valgus deformity progressed with growth. Two patients (aged 10 and 11 years) underwent varus osteotomy of the tibia with partial excision of the fibula. However, their deformity relapsed. Surgical treatment for hip deformity is unnecessary during the growth stage. Progressive deformity of the knee and ankle should be detected in an early stage, and the surgical indication has to be examined.