The clinical impact of global coronal malalignment is underestimated in adult patients with thoracolumbar scoliosis

STUDY DESIGN

Retrospective review of multicenter adult spine deformity (ASD) database.

OBJECTIVES

A recent publication demonstrated that the laterality of the coronal offset is a key parameter that directly impacts postoperative outcomes. The objective of this study is to analyze the relationship between global coronal malalignment (GCM) and functional outcomes in a North American population of ASD patients with no history of previous surgery. The clinical impact of GCM in patients with ASD remains controversial.

METHODS

Primary patients were drawn from a multicenter database of ASD patients and categorized with the Qiu classification: Type A = GCM < 3 cm; Type B = GCM > 3 cm toward the concave side of the curve; and Type C = GCM > 3 cm toward the convex side. In addition to the classic radiographic parameter, the coronal truncal inclination was investigated in regard to the pelvic obliquity. Clinical outcomes, radiographic parameters, and demographics were compared across the three Qiu Types using analysis of variance. The analysis was repeated after propensity matching of the three types by age and sagittal alignment (PI-LL mismatch, pelvic tilt, and sagittal vertical axis).

RESULTS

576 ASD patients (mean age 58.8 years) were included. Type B patients had significantly worse functional scores (Oswestry Disability Index, 36-item Short Form Survey physical component summary, and Scoliosis Research Society-22) and a more severe coronal deformity in terms of maximum Cobb angle, global coronal deformity angle, and coronal malalignment; they were also older (65.4 vs. 58.8 years, p = 0.004) and displayed more severe sagittal malalignment. Similar findings were observed after propensity matching.

CONCLUSIONS

This study is the first to establish an association between functional outcomes and the severity of the coronal plane deformity in the setting of a specific coronal curve pattern in patients without previous surgery. Coronal malalignment significantly affects the health status of patients when the offset is greater than 3 cm in the direction of curve concavity.

LEVEL OF EVIDENCE

III.

Patellofemoral morphology and alignment: reference values and dose-response patterns for the relation to MRI features of patellofemoral osteoarthritis

OBJECTIVE

We aimed to (1) determine reference values for trochlear morphology and patellofemoral (PF) alignment in adults without magnetic resonance imaging (MRI)-defined PF full thickness cartilage damage or knee pain; and (2) evaluate dose-response patterns for these measures with prevalent MRI-defined PF structural damage and/or knee pain.

DESIGN

The Framingham Community Cohort is a population-based sample of ambulatory adults aged ≥50 years. We evaluated six morphology and alignment measures using MRI (n = 985), and reported reference values (mean ± 2SD) in a subsample without MRI-defined PF full thickness cartilage damage or knee pain (n = 563). With restricted cubic spline Poisson regression, we evaluated dose-response patterns of each of the six measures with prevalent MRI-defined PF structural damage or joint pain. Our primary outcome was full thickness cartilage damage.

RESULTS

For dose-response curves, prevalence ratios (PR) increased monotonically for all measures except patellar tilt, which rose with both lateral and medial tilt. Associations were generally strongest in the lateral PF compartment. PR for the strongest predictors of full thickness cartilage damage reached clinical relevance (PR > 1.5) at sulcus angle (SA) ≥135.0°; patellar tilt angle at ≤1.0° and ≥15.0°; and bisect offset ≥57.0%. Lateral trochlear inclination (LTI) achieved PR > 1.5 at ≤23.0° for full thickness cartilage damage with pain.

CONCLUSIONS

SA, patellar tilt, and bisect offset were most strongly associated with full thickness cartilage damage. LTI, patellar tilt and bisect offset had stronger associations with the addition of pain. These findings contribute to better identifying a subset of patients who may benefit from mechanically based interventions.

Scapholunate advanced collapse

This case study reviews the pathophysiology of scapholunate advanced collapse (SLAC), which is the most common etiology of degenerative arthritis in the wrist. The scapholunate ligament serves a critical role in stability of the carpus. Disruption of the scapholunate ligament, its sequela, and the magnetic resonance imaging evaluation are discussed, with review of the defining features of this disease and its progression.

Complications after plate fixation and elastic stable intramedullary nailing of dislocated midshaft clavicle fractures: a retrospective comparison

PURPOSE

The incidence of operative treatment of dislocated midshaft clavicle fractures (DMCF) is rising due to unsatisfactory results after non-operative treatment. Knowledge of complications is important for selection of the surgical technique and preoperative patient counselling. The aim of this study is to compare complications after plate fixation and elastic stable intramedullary nailing (ESIN) with a titanium elastic nail (TEN) for DMCF.

METHODS

A retrospective analysis of our surgical database was performed. From January 2005 to January 2010, 90 patients with DMCF were treated with plate fixation or ESIN. Complications were evaluated in both treatment groups and subsequently compared.

RESULTS

Seven implant failures occurred in six patients (14 %) of the plate group and one implant failure (2.1 %) was seen in the ESIN group (p = 0.051). Major revision surgery was performed in five cases in the plate group (11.6 %) and in one case (2.1 %) in the ESIN group (p = 0.100). Three refractures (7.0 %) were observed in the plate group after removal of the implant against none in the ESIN group (p = 0.105). Six minor revisions (13 %) were reported in the ESIN group and none were reported in the plate group (p = 0.027).

CONCLUSIONS

Compared to other studies we report higher rates of refracture (7.0 %), major revision surgery (11.6 %) and implant failure (14.0 %) after plate fixation. The frequency of implant failures differed almost significantly for patients treated with plate fixation compared to ESIN. Furthermore, a tendency towards refracture after implant removal and major revision surgery after plate fixation was observed.

The Locking Compression Paediatric Hip Plate: technical guide and critical analysis

PURPOSE

Osteotomies of the proximal femur and stable fixation of displaced femoral neck fractures are demanding operations. An LCP Paediatric Hip Plate was developed to make these operations safer and less demanding. The article focuses on the surgical technique and critically analyses the device.

METHODS

Between 2006 and 2008, 30 hips in 22 patients underwent surgery. Patients' demographics, perioperative details, postoperative outcome and complications were retrospectively collected and analysed.

RESULTS

Patients' diagnoses included persistent congenital hip dysplasia (n = 4), neuropathic hip dysplasia (n = 9), idiopathic ante/retroversion (n = 8), femoral neck fracture (n = 3), Perthes' disease (n = 2), deformity after slipped capital femoral epiphysis (SCFE), congenital femoral neck pseudarthrosis, deformity after pelvic tumour resection and malunion following proximal femoral fracture (one each). In 21 of 22 patients, the postoperative radiographs showed corrections as planned. Two cases had to be revised for screw loosening. Intraoperative handling using the plate was excellent in all cases.

CONCLUSIONS

In our case series of 30 hip operations, the LCP Paediatric Hip Plate was shown to be safe and applicable in the clinical setting with excellent results and a low complication rate. We consider that the LCP Paediatric Hip Plate is a valuable device for correction of pathological conditions of the proximal femur and for fixation of displaced femoral neck fractures in children. Larger studies should be carried out to better quantify the risk of clinically relevant complications.

Effects of sex and lower extremity alignment on orientation of the knee joint line in knee surgery

BACKGROUND

Determination of the proper orientation of the knee articular surface is required both for correction of knee malalignment by osteotomy and for correct component alignment in knee arthroplasty. We sought to determine whether the patients' sex and lower extremity alignment (hip-knee-ankle angle) affects proper knee realignment in osteotomy or component alignment in total knee arthroplasty.

METHODS

We examined 199 healthy adult knees with malalignment of < 5° to determine the mechanical medial distal femoral angle, mechanical medial proximal tibial angle, surgical transepicondylar axis angle, and discrepancies between bone-cut orientations of osteotomy or total knee arthroplasty and the joint line of the distal femoral condyles, posterior femoral condyles and proximal tibial plateaus, using a three-dimensional computed tomography model.

RESULTS

The mean mechanical medial distal femoral angle and mean mechanical medial proximal tibial angle were (94.4 ± 1.9)° and (87.6 ± 1.8)° respectively for women and (93.8 ± 2.0)° and (87.1 ± 1.4)° respectively for men. The surgical transepicondylar axis angle was (2.9 ± 1.6)° for women and (3.2 ± 1.7)° for men. Independent of sex, the hip-knee-ankle angle was closely related to the mechanical medial distal femoral angle and mechanical medial proximal tibial angle, but not to the surgical transepicondylar axis angle. A slightly more valgus alignment of the knee and a more valgus angulation of the distal femoral joint line were found in women, whereas a more varus angulation of the proximal tibial joint line was found in men. Sex had the greatest effect on knee joint line orientation when the lower extremity was valgus in alignment.

CONCLUSIONS

A more valgus femoral joint line can be expected in women and in persons with valgus lower extremity alignment; a more varus tibial joint line can be found in men and in persons with varus lower extremity alignment.

The UniSpacer™: correcting varus malalignment in medial gonarthrosis

While options for operative treatment of leg axis varus malalignment in patients with medial gonarthrosis include several established procedures, such as unicompartmental knee arthroplasty (UKA), total knee arthroplasty (TKA) or high tibial osteotomy (HTO), there has been little focus on a less invasive option introduced more recently: the UniSpacer™ implant, a self-centering, metallic interpositional device for the knee. This study evaluates clinical and radiological results of the UniSpacer™, whether alignment correction can be achieved by UniSpacer™ arthroplasty and alignment change in the first five postoperative years. Anteroposterior long leg stance radiographs of 20 legs were digitally analysed to assess alignment change: two relevant angles and the deviation of the mechanical axis of the leg were analysed before and after surgery. Additionally, the change of the postoperative alignment was determined one and five years postoperatively. Analysing the mechanical tibiofemoral angle, a significant leg axis correction was achieved, with a mean valgus change of 4.7 ± 1.9°; a varus change occurred in the first postoperative year, while there was no significant further change of alignment seen five years after surgery. The UniSpacer™ corrects malalignment in patients with medial gonarthrosis; however, a likely postoperative change in alignment due to implant adaptation to the joint must be considered before implantation. Our results show that good clinical and functional results can be achieved after UniSpacer™ arthroplasty. However, four of 19 knees had to be revised to a TKA or UKA due to persistent pain, which is an unacceptably high revision rate when looking at the alternative treatment options of medial osteoarthritis of the knee.

The association between patella alignment and knee pain and function: an MRI study in persons with symptomatic knee osteoarthritis

OBJECTIVE

The aim of the study was to examine the association between patellofemoral (PF) alignment (using standard magnetic resonance imaging (MRI) images of extended knees) and knee pain and function.

DESIGN

Subjects were recruited to participate in a natural history study of symptomatic knee osteoarthritis, called the Boston Osteoarthritis of the Knee Study (BOKS). The association of predictive variable (patellar alignment in sagittal and transverse planes) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function were examined using a linear regression model while adjusting for age, sex, body mass index (BMI), Center for Epidemiologic Studies Depression Scale (CES-D) score and Kellgren and Lawrence score.

RESULTS

Increasing trochlear angle (TA) was associated with both WOMAC (P=0.06) pain and WOMAC function subscale (P=0.04). Increasing lateral patellar title angle (LPTA) and decreasing bisect offset (increasing lateral subluxation) appeared to be associated with increasing WOMAC pain. However, no such an association was observed for other predictors.

CONCLUSIONS

The findings of the present study suggest that increasing TA is associated with increased functional impairment. Other measures of PF malalignment were not significantly associated with either knee pain or functional impairment.

A model to predict the effect of ankle joint misalignment on calf band movement in ankle-foot orthoses

Accurate alignment of anatomical and mechanical joint axes is one of the major biomechanical principles pertaining to articulated orthoses, yet knowledge of the potential effects of axis misalignment is limited. The purpose of this project was to model the effects of systematic linear (proximal-distal and anterior-posterior) misalignments of single axis mechanical ankle joints in an ankle-foot orthosis (AFO) in order to determine the degree and direction of calf band travel that would occur over a functional range of motion. Sagittal plane misalignments of the ankle joint centres of an AFO were simulated using a simple two-dimensional model for both a range of ankle angles and a typical able-bodied ankle kinematic curve for self-selected normal walking speed. The model assumed that no movement occurred between the foot and the foot-plate of the AFO. The model predicted that for anterior (positive horizontal) misalignments, dorsiflexion movements would cause the calf band to travel proximally (i.e., up the leg) and plantar flexion movements would cause the calf band to travel distally (i.e., down the leg). The opposite was predicted for posterior (negative horizontal) misalignments. Proximal (positive vertical) misalignments would cause only distal movements of the calf band while distal (negative vertical) misalignments would cause only proximal movements of the calf band. Anterior-posterior misalignments were found to have a much larger effect on the amount of calf band travel than proximal-distal misalignments.

A longitudinal study of the association between knee alignment and change in cartilage volume and chondral defects in a largely non-osteoarthritic population

OBJECTIVE

It remains unclear whether malalignment of the knee is a cause of knee OA or a marker of disease progression. We investigated whether baseline malalignment of the knee predicts subsequent change in knee cartilage volume and chondral defects in subjects with and without radiographic knee osteoarthritis (OA).

METHODS

A convenience sample of 315 male and female subjects (mean age 45 yrs, range 26-61) was followed up for a mean period of 2.4 years. Anatomic knee alignment was assessed on a standing anterior-posterior semiflexed view of the right knee and defined as the angle subtended by a line drawn through the midshaft of the femur with respect to one drawn through the midshaft of the tibia. T1-weighted fat saturation magnetic resonance imaging scans were performed on the same knee at baseline and followup for cartilage volume and chondral defects.

RESULTS

Knee alignment was normally distributed in this sample with a mean of 178.2 degrees (SD 1.9 degrees). Fifty-five percent of subjects were < 178.5 degrees, while 14% were > 180 degrees. After adjustment for age, sex, body mass index, previous knee injury, and OA family history, neither category of alignment at baseline was associated with subsequent loss of lateral and medial tibial cartilage volume. Similarly, there was no association between malalignment and progression of chondral defects. The results remained the same when stratified by radiographic OA status.

CONCLUSION

Our adequately powered study shows that baseline knee alignment is not associated with subsequent loss of cartilage volume or progression of chondral defects over 2 years. Further studies with a longterm followup are needed, but these results suggest malalignment is primarily a marker of disease progression.

[Fulkerson osteotomy for the treatment of chronic patellofemoral malalignment]

OBJECTIVES

We evaluated the results of Fulkerson osteotomy in patients with chronic patellofemoral malalignment.

METHODS

Fulkerson osteotomy (anteromedial tibial tubercle transfer) was performed in 21 knees of 18 patients (10 females, 8 males; mean age 28.6 years; range 21 to 42 years). The patellofemoral congruence angle, lateral patellofemoral angle, and patellofemoral index were measured pre- and postoperatively on tangential radiograms obtained at 45 degrees knee flexion. Malalignment patterns were determined by computed tomography as lateral tilt (n=12), lateral patellar subluxation (n=4), and both (n=5). All the patients underwent arthroscopic examination preoperatively and all had severe osteoarthrosis in the patellar articular surfaces (Outerbridge type III-IV). The mean anteriorization was 10.5 mm (range 7 to 15 mm). The vastus medialis oblique muscle was advanced in seven knees. The patients were assessed according to the criteria of Fulkerson et al. pre- and postoperatively. The mean follow-up was 28 months (range 20 to 60 months).

RESULTS

According to the criteria of Fulkerson et al., the results were excellent, very good, or good in 18 knees (85.7%), fair in two knees (9.5%), and poor in one knee (4.8%). Pain and instability scores showed significant improvement (p<0.05). On final radiographic assessment, the mean patellofemoral congruence angle and patellofemoral index were -6.8 degrees (range -26 degrees to 10 degrees ) and 1.4 (range 0.8 to 1.6), respectively (p<0.05). The lateral patellofemoral angle had a lateral orientation in all the knees. Complications included tibial tubercle avulsion (n=1), deep vein thrombosis (n=1), and slight knee flexion contractures (n=4). Wound-related problems, compartment syndrome, peroneal nerve palsy, or proximal tibial fracture were not encountered.

CONCLUSION

Successful results are obtained by Fulkerson osteotomy in the treatment of chronic patellofemoral malalignment with severe articular degeneration (Outerbridge type III-IV) particularly in the lateral and distal regions of the patella.

Correction of severe post-traumatic deformities in the distal femur by distraction osteogenesis using Taylor Spatial Frame: a case report

A case of deformity and shortening after post-traumatic growth arrest treated using the Taylor Spatial Frame (Smith & Nephew, Tennessee, USA) is presented. This is the first report showing the application of the frame for post-traumatic deformity in the distal femur, and successful outcomes promise utilization of the frame even for correction of severe deformity in the distal femur.

Structural factors associated with malalignment in knee osteoarthritis: the Boston osteoarthritis knee study

OBJECTIVE

Osteoarthritis (OA) is a multifactorial condition. The progression of knee OA is determined in part by mechanical effects on local structures. One of the mechanical influences on cartilage loss is limb alignment. We explored the structural factors associated with malalignment in subjects with symptomatic OA.

METHODS

We conducted a cross-sectional assessment using The Boston Osteoarthritis of the Knee Study, a natural history study of symptomatic knee OA. Baseline assessments included knee magnetic resonance imaging (MRI) and information on weight and height. Long-limb radiographs to assess mechanical alignment were obtained at 15 months. Subarticular bone attrition, meniscal degeneration, anterior and posterior cruciate ligament integrity, medial and lateral collateral ligament integrity, marginal osteophytes, and cartilage morphology were assessed on MRI using a semiquantitative, multi-feature scoring method (Whole-Organ MRI Score) for whole-organ evaluation of the knee that is applicable to conventional MRI techniques. We also quantified the following meniscal position measures on coronal MRI images in both medial and lateral compartments: subluxation, meniscal height, and meniscal covering of the tibial plateau. Using the long-limb radiographs, mechanical alignment was measured in degrees on a continuous scale. The purpose of this cross-sectional analysis was to determine the individual and relative contribution of various structural factors to alignment of the lower extremity. We assessed the cross-sectional association between various structural factors and alignment of the lower extremity using a linear regression model.

RESULTS

The 162 subjects with all measures acquired had a mean age of 67.0 years (SD 9.2), body mass index 31.4 (SD 5.6); 30% were female and 77% of knees had a Kellgren-Lawrence grade > or = 2. The main univariate determinants of varus alignment in decreasing order of influence were medial bone attrition, medial meniscal degeneration, medial meniscal subluxation, and medial tibiofemoral cartilage loss. Multivariable analysis revealed that medial bone attrition and medial tibiofemoral cartilage loss explained more of the variance in varus malalignment than other variables. The main univariate determinants of valgus malalignment in decreasing order of influence were lateral tibiofemoral cartilage loss, lateral osteophyte score, and lateral meniscal degeneration.

CONCLUSION

Cartilage loss has been thought to be the major determinant of alignment. We found that other factors including meniscal degeneration and position, bone attrition, osteophytes, and ligament damage contribute to the variance of malalignment. Further longitudinal analysis is required to determine cause and effect relationships. This should assist researchers in determining strategies to ameliorate the potent effects of this mechanical disturbance.

Internal derangements of the knee associated with patellofemoral joint degeneration

The objective of the present study was to evaluate whether internal derangements of the knee joint are associated with patellofemoral joint (PFJ) degeneration. Data were collected prospectively from 1,000 consecutive knee arthroscopies. Chondral lesions were observed in 854 patients, and these patients were included in this study. Patients' details (age, sex, duration of symptoms, injuries, and possible mechanism of injury), operative details (types and number of portals, equipment used), intra-articular findings (articular, meniscal and synovial lesions, and stability characteristics) and procedures performed were recorded. Articular lesions were noted on anatomic articular maps of the different functional zones, using a system which presaged the current ICRS system. Using this zoning system, it was easy for the authors to separate the patients with isolated patellofemoral degeneration and arthritis and to do the statistical analysis. Increased incidence of isolated patellofemoral degeneration was noted in patients with synovial shelves, in comparison with patients without shelves (24.7% vs. 15.5%, respectively; P=0.001). Patients with severe patellofemoral maltracking were found to have increased incidence of isolated patellofemoral degeneration in comparison with patients without patella maltracking (64.7% vs. 18% respectively; P<0.001). In conclusion, patellofemoral maltracking and synovial shelves of the knee are highly associated with PFJ degeneration. On the contrary, meniscal tears and ligamentous injuries are associated mainly with degeneration of other compartments of the knee joint and not the PFJ.

Femorotibial and patellar cartilage loss in patients prior to total knee arthroplasty, heterogeneity, and correlation with alignment of the knee

OBJECTIVE

To analyse tibial, femoral, and patellar cartilage loss in patients prior to total knee arthroplasty (TKA), and its correlation with alignment of the knee.

METHODS

26 patients (aged 58 to 86 years) with a clinical indication for TKA were investigated. Quantitative end points of cartilage morphology (T scores for cartilage volume normalised to total subchondral bone area) were determined from coronal and axial magnetic resonance image data, using proprietary software. The static alignment of the knee was determined from standing full limb radiographs.

RESULTS

The magnitude of cartilage loss (T score of normalised cartilage volume) was highly variable within the knee, correlation coefficients ranging from r = 0.17 to 0.51 between cartilage plates. The correlation of cartilage loss with static alignment of the knee (as a continuous variable) was r = -0.52 (p<0.05) for the medial tibia, -0.38 (not significant) for the medial femur, +0.76 (p<0.001) for the lateral tibia, +0.31 (not significant) for the lateral femur, and -0.09 for the patella. When analysing alignment independent of direction (valgus or varus), the correlation for the patella increased to r = 0.30, but remained non-significant.

CONCLUSIONS

Cartilage loss was highly variable among patients and among cartilage plates before knee arthroplasty. Its correlation with alignment was stronger for the tibia than for the femur. There was some evidence for an association of alignment and patellar cartilage loss. These findings stimulate further research on the mechanism and cause-effect relation of alignment and knee osteoarthritis using quantitative magnetic resonance imaging technology.

Bilateral dorsal defect of patellae with patellar hypoplasia and patellofemoral malalignment

Dorsal defect of the patella (DDP) is an uncommon but well-documented disease entity. We report a case of bilateral DDP with patellar hypoplasia and patello-femoral malalignment. Detailed imaging features including radiographic, magnetic resonance imaging, and computed arthrotomographic appearances, are described.

Kombinationen moderner knorpelrekonstruktiver Verfahren

AIM

The aim of this work was to control the results after simultaneous use of different modern resurfacing techniques.

METHODS

We examined the patients who were subjected to different cartilage repair methods using the ICRS score (anterograde drilling, autologous chondrocytes transplantation, OATS, refixation with resorbable pins, spongious bone grafting, HTO).

RESULTS

In two cases the combination of different cartilage regenerative methods in a one-step technique produced a good reconstruction of the joint surface with good clinical outcome. With the implantation of carbon plaques, osteolysis of the spongious bone in combination with an incomplete defect filling can be observed. The therapy must be individual and take the clinical, radiological and intraoperative findings into consideration.

CONCLUSION

The combination of different resurfacing techniques may have success only if the biomechanical properties of the joint with axial malpositioning and ligament instabilities are considered and treated as well. New prospects are offered particularly for young patients with extensive cartilage damage and without other therapeutic options.

Die Bestimmung des AT- und CCD-Winkels am mazerierten Leichenfemur - Eine Vergleichsstudie zwischen CT- und MRT-Messung und Direktmessung am Präparat

PURPOSE

To compare measurements of the real AT (femoral antetorsion) and CCD (caput-collum-diaphysis) angle by computed tomography (CT) and magnetic resonance imaging (MRI) of hip specimen using direct measurements as reference standard, and to show that measurement by MRI can replace CT measurements and may help avoiding X-ray exposition.

MATERIALS AND METHODS

CT and MRI measurements were obtained on 25 in water-arrested macerated human femora. Postprocessing was done by 4 independent readers on a workstation using a dedicated 3D-software. Direct measurements of the real AT and the CCD angle were used as reference standard. The analysis included Student's t test for paired values, interobserver variability using intra-class correlation coefficients (ICC), maximum and middle divergence of the angles, and Bland-Altman plots.

RESULTS

For determining AT and the CCD angle with CT and MRI, good correlation was found between the 4 readers and with measurements using the reference standard. ICCs were 0.97 and 0.90 for measuring AT and CCD angle with CT, and 0.95 and 0.71 for measurements with MRI, respectively. Mean divergence between CT measurements and those of the reference standard was 0.8 degrees for AT and 0.7 degrees for the CCD-angle. Mean divergence between MRI measurements and those of the reference standard was 0.3 degrees for AT and -0.4 degrees for the CCD-angle. Mean divergences between CT and MRI measurements of AT and CCD-angle were 0.5 degrees. Neither systematic errors nor dependences on the qualitative size of the reference data were evident in the divergences of measurements.

CONCLUSION

Measurements of the real AT and CCD angle by CT and MR imaging revealed a good correlation with direct measurements of the femoral specimen and consequently can be recommended for clinical use. MRI measurements can replace CT measurements, avoiding X-ray exposure especially in young patients undergoing preoperative evaluation for hip dysplasia.

Malalignment: signs and significance

Malalignment of the vertebrae, in patients suspected of blunt spinal trauma, is the quintessential sign of spinal injury. Malalignment is obvious in displaced fractures and dislocations but is rarely considered in the diagnosis because of the obvious injury. In patients with more subtle injuries such as those limited to ligamentous structures, vertebral malalignment is the only radiographic sign that leads one to the recognition of the injury. Equally important is the fact that vertebral malalignment may be congenital and may be due to physiologic movement as well as radiographic patient positioning. Recognition of the pattern of traumatic malalignment as distinguished from the appearance of non-traumatic malalignment is essential to accurate radiologic diagnosis. Because malalignment is critical to the radiographic assessment of blunt cervical spine injury, this presentation is limited to the cervical spine. The format of the article includes signs of physiologic and traumatic malaignment as seen on antero-posterior and lateral radiographs of the cervico-cranium and the lower cervical spine.

Varus inclination of the distal femur and high tibial osteotomy

We have analysed retrospectively the relationship between the axial parameters of alignment of the lower limb and the recurrence of varus deformity after high tibial osteotomy. We studied 29 patients (37 knees) with a mean age at surgery of 66 years. The mean follow-up was for 7.4 years (5 to 10.5). Recurrence of varus deformity was defined as an increase in the femorotibial angle of 3 degrees or more, compared with that obtained six months after the operation. There were four patients (four knees) with recurrence of varus deformity. They had a greater varus inclination of the distal femur than those without varus recurrence. An association between varus inclination of the distal femur and horizontal obliquity of the joint surface was observed. Excessive obliquity prevents the shift of weight-bearing to the lateral compartment, and may cause a recurrence of varus deformity after high tibial osteotomy.

Intraoperative control of axes, rotation and length in femoral and tibial fractures. Technical note

In an effort to limit the amount of soft tissue dissection at the fracture site, indirect reduction and minimally invasive fixation techniques have been developed to treat femoral and tibial fractures. These techniques, which do not rely upon anatomical reduction of the fracture fragments, are technically difficult. Correct limb length, axial alignment in the frontal and sagittal plane, and rotation must be assessed using means other than open reduction. In this technical note, some simple and effective intraoperative clinical examination and radiographic techniques to determine limb alignment are described. These include: the 'cable techniques' for the determination of varus-valgus malalignment; the 'hypertension test', 'radiographic recurvatum sign', 'tibial plateau sign', and 'meterstick technique' for length analysis; and the 'hip rotation test', 'lesser trochanter shape sign', 'cortical step sign', and 'diameter difference sign' for rotational analysis. For each of the listed techniques, basic principles, technical instructions, limitations, advantages, and disadvantages are described.

[Osteoma cutis, a case report from the orthopedic viewpoint]

Osteoma cutis is a benign cutaneous disease which causes a primary heterotopic ossification of the skin. Corresponding to the appearance it is possible to distinguish four modifications. The enlargement of osteoma cutis can disturb the function of joints and statics. The etiology of the disease is unknown. Hamartoma or metaplasia is subject of discussion. It is important to mark off osteoma cutis from pseudohypoparathyreoidism (Albright-syndrome++).

A comparison of three methods for measuring patella malalignment in children

This study compared the Insall-Salvati (IS), Blackburne-Peel (BP), and Koshino-Sugimoto (KS) methods for measuring patellar malalignment in children. The IS and BP methods were inaccurate because the traditional landmarks for measurement were absent in the incompletely ossified pediatric knee. The KS method is based on the midpoint of the patella, the distal femoral physis, and the proximal tibial physis. The KS method applied to the extended knee was also inaccurate because of laxity in the patella ligament. However, the KS method applied to the flexed knee was the most accurate method for measuring patella malalignment in children.

Axial lower-limb alignment: comparison of knee geometry in normal volunteers and osteoarthritis patients

Osteoarthritis of the knee is associated with deformities of the lower limb and malalignment of the limb segments. Pathogenetic relationships between the two are poorly understood. Alignment was studied by standardized radiography in 167 symptomatic Canadian osteoarthritis patients, and compared with 119 healthy adult volunteers. In healthy adults overall alignment (hip-knee-ankle angle) was principally determined by distal femoral valgus (condylar hip angle) and proximal tibial-plateau varus (plateau-ankle angle): the angle between the joint surfaces (condylar plateau) was relatively constant. In osteoarthritis, disease-associated differences included condylar-plateau angles that were divergent: accentuated medial convergence in varus osteoarthritis and lateral convergence in valgus osteoarthritis. This was interpreted as change arising from focal loss of cartilage in the medial (varus osteoarthritis) or lateral (valgus osteoarthritis) compartments of the knee. The changes would contribute to increasing limb malalignment during disease progression. But differences of limb geometry also contributed to malalignment. These were the average trends: in varus osteoarthritis there was abnormal femoral geometry (lesser femoral condylar valgus), but tibial surface geometry was the same. In valgus osteoarthritis, the opposite was true: abnormal tibial geometry (lesser plateau varus), but normal femoral geometry. A possible explanation is that these abnormal knee geometries pre-exist and predispose to osteoarthritis, although it is not impossible that they (like condylar-plateau angle) change as disease progresses. Further approaches to population studies are discussed based on these findings, along with their implications for knee surgery.

Radiographic assessment of bony contributions to knee deformity

Our recommendations for standing radiography of the lower limb are that assessments be standardized with respect to limb rotation and fixed relative positions of the hip, knee, and ankle. Specifically, a neutral knee rotation position should be set up, defined as alignment of the flexion plane straight ahead. For a complete appraisal, there should be both AP and lateral views in which the positioning of the patient is the same in all respects. The QPR frame greatly assists in achieving these objectives. Furthermore, the presence of a calibration system adds to the reliability and reproducibility of data by compensating for errors of position or alignment arising from the placement of the source and the film. Standardization of positioning also improves the detectability of axial-rotational deformities on comparison of AP and lateral views, providing more reliable indications of the need for CT than possible with nonstandardized short views. When a skyline patellar radiograph is added to the QPR routine, the end result is an excellent appraisal of lower limb alignment, providing a solid basis for diagnosis and planning of appropriate surgical remedies.

Malalignment and degenerative arthropathy

The axial relationship of the joints of the lower extremity reflects both alignment and orientation. Static considerations are useful for preoperative planning and deformity correction, but dynamic considerations including compensatory gait may be more relevant clinically. Laboratory animal models have been developed that simulate the deleterious effect of malalignment on articular cartilage. Malalignment disturbs the normal transmission of force across the knee, and altered stress distribution related to deformity has been demonstrated in cadaver models using pressure-sensitive film. No prospective data are available to document the natural history of malalignment, but several retrospective studies suggest the clinical course is one of gradual progression resulting in degenerative arthropathy. The long-term follow-up of fractures is less definitive, and difficult to interpret considering the bias inherent in patient selection. Although direct clinical evidence of a cause-and-effect relationship between malalignment and arthrosis has not been possible, substantial evidence from the orthopedic literature supports this hypothesis.

Deformity planning for frontal and sagittal plane corrective osteotomies

The authors have developed a universal system of geometric deformity planning based on the mechanical or anatomic axes. The place where the axes intersect is the center of rotation angulation (CORA) of a deformity. Osteotomy level and type should be considered relative to the CORA to avoid creating secondary deformities. This type of planning is applicable to both frontal and sagittal plane deformities.

Effects of tibial malalignment on the knee and ankle

It is widely believed that excessive angulation of the tibia may predispose the ankle and knee to osteoarthritic degeneration. There is no general agreement, however, regarding the acceptable limits of angulation. The authors used cadaver models to measure the contact areas for the cartilage in the ankle, as well as the contact areas and pressures for the cartilage in the knee, as a function of the level and magnitude of simulated angular deformities of the tibia. The quantitative relationships between fracture angulation and joint contract conditions developed in these experiments may help in the formation of more specific guidelines for the treatment of tibial fractures.

Use of a modified Elmslie-Trillat procedure to improve abnormal patellar congruence angle

Forty patients underwent 45 modified Elmslie-Trillat realignment procedures (mean followup, 2 years) for refractory patellar instability (34 knees) or painful patellofemoral syndrome with malalignment (11 knees). The postoperative congruence angle (mean, +3.4 degrees) was significantly improved compared with the preoperative value (mean, +21.5 degrees). We considered the "normal" congruence angle average as -8 degrees (range, -20 degrees to +4 degrees). Over time postoperatively, we detected no statistical difference in the congruence angle (5 months, 3.4 degrees; 24 months, 6.3 degrees). There were no patellar dislocations postoperatively. Nine knees (20%) had some postoperative subluxation. Ninety-four percent of the patients without subluxation had congruence angles less than 15 degrees, whereas 54% of patients with postoperative subluxation had postoperative congruence angles greater than 15 degrees. The evidence in this study population indicates that the modified Elmslie-Trillat procedure can predictably improve the patellar congruence angle. Adequate correction may eliminate patellar dislocation. Correction of the congruence angle to less than +15 degrees will result in a decreased incidence of postoperative patellar instability. Early full activity postoperatively did not affect the modified Elmslie-Trillat correction of the congruence angle being maintained over time.

Patellofemoral malalignment in adolescents. Computerized tomographic assessment with or without quadriceps contraction

Twenty-seven adolescents with anterior knee pain with or without patellar instability were studied by computerized tomography to detect patellofemoral malalignment. The examination was performed with and without quadriceps contraction with the knee flexed to 15 degrees. Congruence angle, patellar tilt angle, sulcus angle, and trochlear depth were measured. This investigation showed the well-known types of patellofemoral malalignment with quadriceps relaxed (tilted, lateralized, lateralized, and titled patella) and, in 52% of cases, revealed changes in type and severity with quadriceps contraction (in 41%, lateralization and tilting were markedly more evident; in 11%, the type of malalignment changed). The results demonstrate that, in addition to assessment with quadriceps relaxed, computerized tomography with quadriceps contraction is a useful adjunct to diagnose and define the type of malalignment in particularly difficult circumstances.