Femoral Varus Research Articles

Early clinical and radiological outcomes after double osteotomy in patients with late presentation Legg-Calvé-Perthes disease

Legg-Calvé-Perthes disease is an idiopathic avascular necrosis of the femoral head. Although many surgical approaches to treat the late presentation of this pathology have been proposed, there are few reports about the early results of the double osteotomy procedure (femoral varus osteotomy combined with Salter innominate osteotomy). The purpose of this study was to describe the early results obtained with the double osteotomy in patients with late presentation of Legg-Calvé-Perthes disease. Cross-sectional evaluation of ten patients intervened with double osteotomy. There were seven males and three females with a mean age of 9.2 +/- 1.7 years [standard deviation (SD)]. The average post-surgical time of evaluation was of 46.5 +/- 26.2 months. Of the ten evaluated patients, four had a Catterall III and six had a Catterall IV disease. According to Herring classification, three patients were Herring B and seven were Herring C. The epiphyseal extrusion average before and after the surgical procedure was 19.3 +/- 12.4 and 12.1 +/- 14.9%, respectively. In accordance with the Ratliff classification and Lloyd Roberts radiological results, the following were the postoperative clinical results: four good, five fair and one poor. Based on the Stulberg classification, there was one patient in class I, five in class II, three in class III and one in class IV. The surgical treatment for late Perthes disease with the best expected outcome is still a challenge. According to the resultsreported here, the double osteotomy could be considered as an alternative to treat this entity.

Long-Term Results of Proximal Femoral Osteotomy in Legg-Calvé-Perthes Disease

Legg-Calvé-Perthes disease is a childhood hip disorder that may result in a deformed and poorly functioning hip. The purpose of this study was to evaluate the correlation between hip deformity at skeletal maturity and degenerative osteoarthritis and to present the long-term results of proximal femoral varus derotational osteotomy in Legg-Calvé-Perthes disease. We analyzed the results of 40 patients (43 hips), who underwent proximal femoral varus derotational osteotomy for Legg-Calvé-Perthes disease in our institution between 1959 and 1983. All available patients underwent a single long-term follow-up examination. Hips were classified with the classification system of Stulberg. Osteoarthritis was evaluated using the Tönnis classification. The long-term outcomes were evaluated after a mean follow-up period of 33 years. When examining the outcome using the Stulberg classification system, there were 8 Stulberg class I hips (19.5%), 15 Stulberg class II hips (36.6%), 8 Stulberg class III hips (19.5%), 9 Stulberg class IV hips (22%), and 1 Stulberg class V hip (2.4%). One patient, who had a bilateral Legg-Calvé-Perthes disease, underwent total hip replacement for osteoarthritis. Seven patients had poor clinical results. Proximal femoral varus derotational osteotomy provides good long-term results for Legg-Calvé-Perthes disease. The Stulberg classification is a good predictor for patient outcome. Level IV, therapeutic study.

Prognostic factors and outcome of treatment in Perthes’ disease

This nationwide prospective study was designed to determine prognostic factors and evaluate the outcome of different treatments of Perthes' disease. A total of 28 hospitals in Norway were instructed to report all new cases of Perthes' disease over a period of five years and 425 patients were reported and followed for five years. Of these, 368 with unilateral disease were included in the present study. The hips were classified radiologically according to a modified two-group Catterall classification and the lateral pillar classification. A total of 358 patients (97%) attended the five-year follow-up, when a modified three-group Stulberg classification was used as a radiological outcome measure. For patients over six years of age at diagnosis and with more than 50% necrosis of the femoral head (152 patients), the surgeons at the different hospitals had chosen one of three methods of treatment: physiotherapy (55 patients), the Scottish Rite abduction orthosis (26), and proximal femoral varus osteotomy (71). Of these hips, 146 (96%) were available for the five-year follow-up. The strongest predictor of outcome was femoral head involvement of more or less than 50% (odds ratio (OR) = 7.76, 95% confidence interval (CI) 2.82 to 21.37), followed by age at diagnosis (OR = 0.98, 95% CI 0.92 to 0.99) and the lateral pillar classification (OR = 0.62, 95% CI 0.40 to 0.98). In children over six years at diagnosis with more than 50% of femoral head necrosis, proximal femoral varus osteotomy gave a significantly better outcome than orthosis (p = 0.001) or physiotherapy (p = 0.001). There was no significant difference between the physiotherapy and orthosis groups (p = 0.36), and we found no difference in outcome after any of the treatments in children under six years (p = 0.73). We recommend proximal femoral varus osteotomy in children aged six years and over at the time of diagnosis with hips having more than 50% femoral head necrosis. The abduction orthosis should be abandoned in Perthes' disease.

Fracture incidence following plate removal in Legg–Calvé–Perthes disease: A 32-year study

The decision of whether or not to remove pediatric metallic implants remains a controversial issue. Many factors have been cited both in favor and against routine removal of metallic implants. The purpose of this study was to determine the fracture rate following the routine removal of hardware from patients with Legg-Calvé-Perthes (LCP) disease treated by proximal femoral varus osteotomy (PFVO) and to determine if there is an optimal time to remove hardware in this population. We performed a retrospective chart review of children who had PFVO with subsequent hardware removal from March 1973 to May 2005 performed by a single surgeon. A total of 196 hips in 184 patients were included. Data was analyzed using logistic regression. Inverse prediction was also used to obtain estimates of the time needed to produce probabilities of no fracture. Ten out of the 196 hips included (5.1%) sustained a fracture after plate removal. The time from osteotomy to plate removal averaged 10.4 months in the nonfracture group and 4.8 months in the fracture group. This was statistically significant (P < 0.0001). Using the logistic regression model, the predicted time to plate removal corresponding to a 95% probability of no fracture was between 5.1 and 8.4 months. Plate removal remains a reasonable choice but questions remain as to the timing of removal. These data suggest that patients may benefit from extending the time to hardware removal beyond radiographic union to at least six months or more after the osteotomy.

Arthrographic indicators for decision making about femoral varus osteotomy in Legg-Calvé-Perthes disease

There is not always a good outcome after a femoral varus osteotomy (FVO) in those with Legg-Calvé-Perthes disease (LCPD), even when the severity warrants surgical treatment. The purpose of this study was to find arthrographic indicators for decision making regarding the likely surgical outcome of a FVO. We used an image of an abduction position during preoperative arthrography under general anesthesia that simulated the post-operative relationship between the femoral head and the acetabulum. In the image, we defined two indicators of how deeply the deformed epiphysis was contained within the acetabulum: an acetabular head index in abduction and an epiphyseal slip-in index. Finding the contact point between the top of epiphysis and acetabulum was the key for the epiphyseal slip-in index measurement. In 37 patients (38 hips) who underwent FVOs based on our inclusion criteria, these two indices were measured retrospectively and were analyzed for a correlation with surgical outcome. Surgical outcome was evaluated using a combination of three factors: sphericity of the femoral head (Stulberg's classification), acetabular cover (acetabular head index), and the slope of acetabular roof. The outcome was acceptable in 20 hips (52.6%) and unacceptable in18 hips (47.4%). There was a statistically significance difference in epiphyseal slip-in index between the acceptable group (21.9 +/- 2.8%) and the unacceptable group (15.0 +/- 4.4%) (P < 0.0001). An index of 20% or more determined a safe zone for predicting an acceptable outcome with 80% sensitivity, 89% specificity, and a 7.2 likelihood ratio. However, the acetabular head index in abduction showed no such statistical significance. In this study, we found that the epiphyseal slip-in index was a reliable indicator for predicting the effectiveness of a FVO. It is worth measuring this index when a surgeon is considering a FVO for a patient with severe LCPD. (Level of Evidence Level III.).

Comparison of Radiographic and Anatomic Femoral Varus Angle Measurements in Normal Dogs

To determine if the clinically practiced method of radiographic femoral varus angle (R-FVA) measurement is repeatable, reproducible, and accurate. Radiographic and anatomic study. ANIMALS/SAMPLE POPULATION: Normal Walker hound cadavers (n=5) and femora (n=10). Cadavers were held in dorsally-recumbent and torso-elevated positions as 3 craniocaudal radiographs were made of each femur, by each of 2 different technicians. Femora were then harvested for direct measurement of anatomic femoral varus angle (A-FVA). R-FVA was measured on each radiograph by each of 3 examiners on 3 separate occasions. Intra-observer (repeatability) and inter-observer (reproducibility) variance in R-FVA measurement and the strength of relationship between R-FVA and A-FVA (accuracy) were determined. Mean (+/-SD) A-FVA was 5.2+/-2.1 degrees (range, 2.4-8.2 degrees). Mean (+/-SD) R-FVA was 5.8+/-1.0 degrees (range, 2.7-9.6 degrees). Intra-observer variance (range: 11-16%) and inter-observer variance (16%) were acceptable. The strength of relationship between measured R-FVA and A-FVA (maximum adjusted R(2)<0) was unacceptably low regardless of observer, patient position, or radiographic technician. R-FVA measurement was repeatable and reproducible, but not statistically accurate in predicting A-FVA in these 5 normal Walker hounds. The detected inaccuracy may be real or the result of a selection bias for normal dogs obscuring the true relationship. R-FVA may not be an accurate method of femoral varus measurement in dogs with A-FVA<10 degrees. Using Slocum's criteria for distal femoral osteotomy (R-FVA>10 degrees), the procedure would not have been erroneously performed in any of the normal dogs of this study.

Bilateral valgus-extension osteotomy of hip using hybrid external fixator in spondyloepiphyseal dysplasia: early results of a salvage procedure

The treatment of spondyloepiphyseal dysplasia (SED) congenita patients with severe bilateral hip involvement is difficult because it involves deformities of multiple joints and of the spine. The purpose of this study was to evaluate the results of the procedure described below as a method of treatment for bilateral hip involvement in SED congenita patients. We performed proximal femoral valgus-extension osteotomy with distal femoral varus osteotomy using a hybrid external fixator in eight patients (seven male patients and one female patient) or 16 hips. The patients had a mean age of 16.37 years (range, 9-25 years) at the time of surgery. The mean valgus angle at the proximal osteotomy site was 53.4 degrees on the right side and 52.5 degrees on the left side, and the mean varus angle at the distal osteotomy site was 22 degrees . Mean fixator time was 19.8 weeks (range, 10-42 weeks). After an average follow-up of 25.9 months, the mean modified Harris hip score had improved from 67.9 points to 79.1 points, which was statistically significant (P=0.012). Preoperative knee range of motion was achieved at the last follow-up in all patients. Waddling gait was absent in three patients, reduced in four patients, and was the same in one at the last follow-up. Mean limb length gain was 3.5 cm (range, 0-5 cm), mean limb length discrepancy less than 0.5 cm, and the mechanical axis was realigned in all. In conclusion, our early results suggest that proximal valgus-extension osteotomy with distal femoral varusization can be a useful treatment option in young patients with bilateral hip involvement in SED congenita.

Operative Reconstruction of the Severe Sequelae of Infantile Septic Arthritis of the Hip

We retrospectively reviewed the results of operative reconstruction of 21 hips in 21 patients with severe sequelae due to infantile septic arthritis of the hip. Eleven hips were classified as Choi type IIIA, 4 as type IIIB, 1 as type IVA, and 5 as type IVB sequelae. The average age at the time of the first surgery was 4.2 years, and the average follow-up period was 8.9 years. Successful results were obtained in 8 of the 11 type IIIA hips by means of a combination of open reduction, femoral varus osteotomy, and pelvic osteotomy. However, only 2 of the 4 type IIIB hips treated by femoral valgus osteotomy and/or bone grafting and 2 of the 6 types IVA and IVB hips treated by greater trochanter arthroplasty had successful results.

Treatment of medial patellar luxation by femoral closing wedge ostectomy using a distal femoral plate in four dogs

This case report describes the treatment of recurrent medial patellar luxation associated with varus deformity of the distal femur by distal femoral ostectomy stabilised using a distal femoral plate. Four dogs (five affected limbs) were included in the study. All cases had received previous surgery for medial patellar luxation but remained significantly lame. All were treated by femoral ostectomy to correct distal femoral varus deformity with application of a distal femoral bone plate. All cases improved following surgery. An excellent outcome was recorded in four of five cases. Lameness persisted in one case despite satisfactory patellar stability as a result of concurrent cranial cruciate ligament deficiency. One case suffered implant failure. Femoral ostectomy is an effective treatment for medial patellar luxation associated with femoral varus deformity. The distal femoral plate provides a convenient method by which to stabilise the ostectomy. Care should be exercised when the 2 mm distal femoral plate is applied.

Long-term outcome of distal femoral osteotomy for treatment of combined distal femoral varus and medial patellar luxation: 12 cases (1999–2004)

To determine long-term outcome of distal femoral osteotomy as a component of treatment for distal femoral varus and medial patellar luxation in large-breed dogs. Retrospective case series. 12 dogs (16 stifle joints). Medical records and radiographs were reviewed to identify large-breed dogs with medial patellar luxation (grade > or = 2) and femoral varus angle > or = 12 degrees treated with distal femoral osteotomy, with a minimum follow-up (by a veterinarian) of 18 months. Signalment, weight, medial patellar luxation and lameness grade, pre- and postoperative femoral varus angle, surgical technique, time to radiographic bone union, and complications were recorded. Follow-up with owners via questionnaire was performed > 18 months after surgery. 16 corrective distal femoral osteotomies were performed with ancillary medial patellar luxation procedures in 12 dogs; 4 dogs had staged bilateral procedures. Mean +/- SD preoperative and postoperative femoral varus angles were 16.3 +/- 4.3 degrees and 3.9 +/- 2.5 degrees , respectively. Mean +/- SD time to radiographic union of the distal femoral osteotomy was 52.6 +/- 13 days. One dog had Kirschner wire migration from the tibial tuberosity. Patellar luxation was not detected after surgery in any dog. Mean +/- SD follow-up by a veterinarian was 1,335 +/- 410 days and by use of an owner questionnaire was 1,497 +/- 464 days. All 10 variables of owner-observed patient comfort and function were significantly improved. Distal femoral osteotomy in combination with traditional treatment provided predictable osteotomy healing, patellar stabilization, and long-term improvement in patient comfort and function when used to treat combined distal femoral varus and medial patellar luxation in large-breed dogs.

A biomechanical study of the modified intertrochanteric valgus osteotomy:a three-dimensional finite element analysis

Objective To evaluate the differences in biomechanical performance between the traditional Bombelli-type and modified Z-type valgus osteotomies through finite element analysis. Methods The CT images obtained from a standardized composite femur were used to create 4 solid femoral models and hexahedral finite element meshes of intertrochanteric valgus with the preoperative neck-shaft angle at 120°, 110°, 100° and 90° respectively. Four finite element models with the postoperative neck-shaft angle corrected at 150° for each type of osteotomy were then created. Single leg stance was applied in simulated loading on each finite element model, and the material properties were assumed linear, isotropic and homogeneous. The stress distribution in the postoperative femora and fixation plate as well as the normal contact force of the osteotomized plane were analyzed and compared between the 2 types of osteotomy through the 4 models. Results Serious deformity and high local stress near the osteotomized plane were found in Bombel- li-osteotomized femur with preoperative femoral shaft-neck angle at 90° However, no obvious difference in the stress distribution was found among the 4 Z-osteotomy models. The deformity in Z-osteotomy models was less than that in the Bombelli-osteotomy models. Besides, the stress distributed on osteotomized plane in Z-osteotomy was higher than that in the traditional Bombelli-osteotomy when the preoperative femoral shaft-neck angle was 90°. Conclusion The Z-osteotomy may be a better alternative for large range correction of intertrochanteric varus of femur. Key words: Femur; Osteotomy; Biomechanics

Doubles ostéotomies assistées par ordinateur dans les grands genu varum: Résultats préliminaires à propos de 16 cas

Purpose of the study The aim of this work was to assess radiographic outcome after double femoral and tibial osteotomy for severe genu varum. Among 197 computer-assisted osteotomies performed in our department between August 2001 and February 2006, 16 (8.1%) were double level osteotomies. Material and methods Five women and nine men, mean age 51.19±11.15 years (range 20-63 years) underwent surgery (both sides for two men). The right side was involved in nine cases, the left in seven. Inclusion criteria were genu varum > 10° and/or a mechanical femur angle ≥90° in a context of a varus tibial mechanical axis. Exclusion criteria were a femoral mechanical angle at 90° and a tibial mechanical angle > 88°. Using the modified Ahlbäck classification, the knees were: grade 2 (n=1), grade 3 (n=9), grade 4 (n=4) and grade 5 (n=1). One patient did not present osteoarthritic degradation but a particularly unaesthetic deformity. The radiological femorotibial mechanical angle (HKA) measured preoperatively was on average 168.44°±2.42° (range 164°-173°). The average preoperative femoral mechanical angle was 87.38°±2.45° (range 81°-90°) and the mechanical tibial angle was 84.5°±2.19° (range 80°-88°). The main preoperative objective was to obtain a mechanical femorotibial angle of 182°±2° without an oblique joint space giving a tibial mechanical angle of 90±2°). All operations were computer-assisted using the Orthopilot TM navigation system. After acquisition of the mechanical axis, the closed wedge lateral distal femoral osteotomy was performed first to achieve the desired femoral correction. The open wedge proximal medial tibial osteotomy was then performed to obtain the planned femorotibial mechanical axis. A control goniometry in the weight bearing position was obtained three months postoperatively. Results There were no complications. The mean preoperative computer-measured HKA was 168.63°±2.22° (range 164°-173°), i.e. an angle corresponding perfectly with the preoperative goniometry. After the osteotomies, the mean computer-measured mechanical angle was 183°±0.94° (range 181°-184°). Three months after the operation, the weight-bearing goniometry gave a mean HKA angle at 181.25°±1.84° (range 177°-184°). The mean femoral mechanical angle was 93.13°±2.25° (range 89°-97°) and the mean tibial mechanical angle was 90.31°±1.20° (range 88°-92°). The preoperative objective was achieved in 14 of the 16 patients (87.5%). The two failures were undercorrections (177° and 179°). Joint spaces were not oblique on the x-rays. Discussion Tibial osteotomy is an excellent method for the treatment of osteoarthritic genu varum. However, in patients with very severe deformity, femoral varus is also involved so that the overcorrection necessary to achieve a good result (3-6° valgus) could often produce an oblique joint space corresponding to excessive tibial valgus. Since osteotomy is generally considered as a palliative measure before later implantation of a total prosthesis, an oblique joint surface would compromise the success of the subsequent surgery. Double-level osteotomy is a way to avoid this problem, keeping in mind that the risk of over or under correction is not negligible for this difficult operation. We used our experience with computer-assisted navigation for total knee arthroplasty and for tibial osteotomy to prepare this technique for double-level osteotomy. Conclusion Computer-assisted double-level osteotomy is a reliable, accurate and reproducible method for the treatment of severe genu varum. The two failures observed in this series were within a tolerable range (177° and 179°). The use of a navigation procedure simplifies a technique which in general requires skillful application to achieve the preoperative objective. The development of this technique is important in order to avoid an oblique joint space which can compromise the success of subsequent prosthesis implantation.

Long-Term Follow-Up of Distal Femoral Varus Osteotomy of the Knee

Distal femoral varus osteotomy (DFVO) of the knee may be indicated for young, active patients with unicompartmental arthritis and valgus deformity. We report on 40 DFVOs with a mean follow-up of 123 months. At the most recent follow-up, 24 knees had good or excellent results (60%), 3 had fair results (7.5%), and 3 had poor results (7.5%). Four in the fair/poor group were awaiting total knee arthroplasty. Eight knees (20%) had been converted to total knee arthroplasty. Mean Knee Society objective score improved from 18 (range, 0-74) to 87.2 (range, 50-100). Mean Knee Society function score improved from 54 (range, 0-100) to 85.6 (range, 40-100). Ten-year survival rate of the DFVO was 82% (95% confidence interval, 75%-89%) and the 15-year survival rate was 45% (95% confidence interval, 33%-57%).

Treatment of osteonecrosis of the femoral head with implantation of autologous bone-marrow mononuclear cells

Idiopathic osteonecrosis of the femoral head commonly develops during adolescence and in the prime of adulthood. In Japan, joint-preserving procedures such as transtrochanteric rotational osteotomy, femoral varus osteotomy and vascularized bone grafting are often the surgical treatments of choice. However, the results of these procedures are not necessarily satisfactory. These procedures force patients to endure longer waits for their entire treatment. In addition, it is often difficult for surgeons to choose the appropriate treatment, especially in patients who have bilateral extensive osteonecrosis. We reported transplantation of bone marrow mononuclear cells for osteonecrosis of the femoral head and short-term results.

Multiplanar Deformity Analysis of Untreated Blount Disease

Although varus malalignment of the proximal tibia is the primary pathology in Blount disease, other deformities may exist. To assess multiplanar lower limb deformities, children with previously untreated early- and late-onset Blount disease who subsequently needed surgical correction were identified. Preoperative frontal and sagittal plane deformity analysis using Paley's methodology and rotational profile assessment using prone clinical examination were performed by a single examiner. Results were compared between the 2 groups and with uninvolved limbs within each group. Additionally, rotational profile of the lower limb was compared with age-matched values. Over an 8-year period, 60 limbs (40 patients) including 26 with early-onset and 34 with late-onset Blount met the inclusion criteria. Although both groups exhibited proximal tibial varus, procurvatum, and internal torsion, patients with early-onset Blount disease had greater severity. Unlike the younger patients, approximately one third of the varus malalignment of the affected extremity was attributed to the distal femur in the late-onset patients. Neither group showed any significant deformity of the proximal femur and distal tibia or sagittal plane deformity of the distal femur. There was a correlation between the severity of varus malalignment of the limb with magnitude of proximal tibial deformities in both groups and with distal femoral varus in the late-onset group of patients. Multiplanar deformity analysis is a valuable tool in the comprehensive evaluation of children with Blount disease.

Clinically unrecognized intravascular placement of epidural catheter in a child – an argument for the use of radio‐opaque contrast?

An epidural catheter was inserted after induction of anesthesia in a 28.2 kg 9-year-old boy scheduled to undergo bilateral femoral varus derotational osteotomies. There was no gravity free flow of blood down the catheter and there was no blood aspirated with a 2 ml syringe. After a negative test dose of a 4 ml solution of 0.25% levobupivacaine with epinephrine 1 : 200 000, a further 8 ml was administered via the epidural catheter. No significant increase in heart rate was noted. On surgical skin incision the heart rate increased from 94 to 116 b.min(-1) and blood pressure increased from 104/44 to 116/46 mmHg. A further 3 ml 0.25% levobupivacaine with epinephrine and clonidine 2 mug.kg(-1) were administered via the epidural catheter. The operation continued uneventfully although it was noted that the heart rate increased intermittently during the procedure. In view of the unexplained tachycardia and a history of cerebral palsy with the potential for postoperative muscle spasms, it was felt important to have a reliable epidural. To confirm placement, 2 ml of Isovue 300 (Iopamidol) was administered via the epidural catheter. X-ray screening demonstrated intravascular placement and the rapid disappearance of contrast. The catheter was removed and reinserted. Contrast demonstrated good spread in the epidural space. The merits of screening with contrast for epidural catheter placement in children are discussed.

Operative treatment of bilateral hip dislocations in a child with metatropic dysplasia

We present a case of bilateral hip dislocations with metatropic dysplasia. Radiographic features such as narrow thorax, dense wafer vertebral bodies, narrowing interpedicular distances, kyphoscoliosis, crescent-shaped iliac wings, dumbbell-shaped tubular bones, and inferiorly directing lesser trochanter conform to the findings of metatropic dysplasia. Hip dislocations were misdiagnosed by ultrasonographic and radiographic hip screening, owing to the severely deformed femoral heads and acetabulums. The diagnosis of hip dislocations became possible by magnetic resonance imaging. The bilateral hip dislocation was reduced by open reduction of the hip joints and femoral derotation varus osteotomies.

Factors affecting femoral varus osteotomy in cerebral palsy: a long-term result over 10 years

The present study was conducted to review the long-term results of femoral varus osteotomy with/without pelvic osteotomy of spastic cerebral palsy. We also evaluated the spastic hip score with following factors: migration index of Reimer's, Shenton's line, shape of the femoral head, shape of the roof of the acetabulum, and presence of windblown effect. Of the 31 children (61 hips) reviewed, 49 hips (80%) had satisfactory outcomes after 10 years of follow-up. Twelve hips showed unsatisfactory outcomes with recurrent dislocation or significant osteoarthritis. A low preoperative spastic hip score was more indicative of a better outcome.

Hip pain from impingement and dysplasia in patients aged 20–50 years. Workup and role for reconstruction

In the 20–50-year age group, hip pain usually indicates dysplasia. Chronic mechanical pain is the usual pattern, although acute pain caused by avulsion or degeneration of the labrum may occur. The morphological characteristics of the dysplastic hip should be evaluated, and the link between the dysplasia and the osteoarthritis should be confirmed. Three factors indicate a favorable prognosis: joint space preservation, age younger than 40 years, and correctable femoral and acetabular abnormalities. Reconstruction is highly desirable, as it delays the need for joint replacement by 20 years. After 15 years, good outcomes are seen in 87% of patients after shelf arthroplasty and 85% after femoral varus osteotomy with or without shelf arthroplasty. Chiari acetabular osteotomy can be performed in patients with osteoarthritis but is followed by prolonged limping. Periacetabular osteotomy should be reserved for patients with moderate dysplasia and no evidence of osteoarthritis. Shelf arthroplasty and femoral osteotomy require 5–8 months off work (compared to 5 months after hip replacement surgery) but subsequently permits a far more active lifestyle. Hip replacement, which is required 20 years or more after biologic reconstruction, carries the same prognosis as first-line hip replacement (good results in 80% of patients after 15 years). Acute sharp pain related to anterior hip derangement also occurs in primary femoroacetabular impingement (FAI). The most common pattern is cam impingement, which is due to a decrease in head–neck offset and manifests as pain during flexion and adduction of the hip. Cam impingement can be corrected by anterolateral osteoplasty, which is often performed arthroscopically. Pincer-type impingement is contact between the anterior acetabular rim and the femoral neck due to retroversion of the proximal acetabulum. The imaging study strategy is discussed. Coxometry, computed tomography, and arthrography can be used. Primary FAI, which occurs as a result of geometric abnormalities, should be distinguished from secondary impingement. Causes of secondary impingement include exaggerated lumbar lordosis with pelvic tilt and to hip osteophytosis (sports or posterior hip osteoarthritis). Osteoplasty is rarely appropriate in patients with secondary impingement. The features of acute anterior hip derangement are now better defined. They can be used to guide palliative treatment, which is effective, in the medium term at least. Experience acquired over the last two decades has established the efficacy of surgery for hip dysplasia.

RADIOGRAPHIC AND COMPUTED TOMOGRAPHIC DETERMINATION OF FEMORAL VARUS AND TORSION IN THE DOG

Diagnosis and quantification of femoral varus and femoral torsion using radiographs is technically challenging due to the difficulty in determining proper positioning. The purpose of this study is to describe a computed tomographic technique for determination of femoral varus and femoral torsion and to compare this technique, and standard radiography, to anatomic preparation, for the measurement of femoral varus and femoral torsion in normal dogs. Nine canine cadavers, visually and radiographically free of orthopedic disease of the hip and stifle joints, were utilized for analysis. Femoral varus was determined using a craniocaudal radiograph, a craniocaudal radiograph obtained after confirming accurate positioning using horizontal beam fluoroscopy, and computed tomography (CT). Femoral torsion (expressed as angle of version) was determined using an axial radiographic projection obtained from distal to proximal and CT. Each femur was dissected free of soft tissues, and direct determination of femoral varus and femoral torsion was performed using digital photographic images. All radiologic and photographic images were digitally measured to quantify the magnitude of femoral varus and femoral torsion. For femoral varus, no difference (P = 0.149) between the three different imaging techniques and the anatomic preparation was identified. For femoral torsion, no difference (P = 0.059) between the two imaging techniques and the anatomic preparation was identified. Well positioned radiographs and the described computed tomographic method are both as accurate as anatomic preparation for the measurement of both femoral varus and femoral torsion in normal dogs.