Coronal Plane Alignment of the Knee (CPAK) classification.

AIMS: A comprehensive classification for coronal lower limb alignment with predictive capabilities for knee balance would be beneficial in total knee arthroplasty (TKA). This paper describes the Coronal Plane Alignment of the Knee (CPAK) classification and examines its utility in preoperative soft tissue balance prediction, comparing kinematic alignment (KA) to mechanical alignment (MA). METHODS: A radiological analysis of 500 healthy and 500 osteoarthritic (OA) knees was used to assess the applicability of the CPAK classification. CPAK comprises nine phenotypes based on the arithmetic HKA (aHKA) that estimates constitutional limb alignment and joint line obliquity (JLO). Intraoperative balance was compared within each phenotype in a cohort of 138 computer-assisted TKAs randomized to KA or MA. Primary outcomes included descriptive analyses of healthy and OA groups per CPAK type, and comparison of balance at 10° of flexion within each type. Secondary outcomes assessed balance at 45° and 90° and bone recuts required to achieve final knee balance within each CPAK type. RESULTS: There was similar frequency distribution between healthy and arthritic groups across all CPAK types. The most common categories were Type II (39.2% healthy vs 32.2% OA), Type I (26.4% healthy vs 19.4% OA) and Type V (15.4% healthy vs 14.6% OA). CPAK Types VII, VIII, and IX were rare in both populations. Across all CPAK types, a greater proportion of KA TKAs achieved optimal balance compared to MA. This effect was largest, and statistically significant, in CPAK Types I (100% KA vs 15% MA; p < 0.001), Type II (78% KA vs 46% MA; p = 0.018). and Type IV (89% KA vs 0% MA; p < 0.001). CONCLUSION: CPAK is a pragmatic, comprehensive classification for coronal knee alignment, based on constitutional alignment and JLO, that can be used in healthy and arthritic knees. CPAK identifies which knee phenotypes may benefit most from KA when optimization of soft tissue balance is prioritized. Further, it will allow for consistency of reporting in future studies. Cite this article: Bone Joint J 2021;103-B(2):329-337.

Effect of pelvic obliquity on the orientation of the acetabular component in total hip arthroplasty.

In infrapelvic obliquity, coronal pelvic malrotation entails a change in the spatial location of the bony acetabulum. In the present study, 77 patients presented with infrapelvic obliquity with types 1 and 2 hip pathologies in which the pelvis is lower and higher, respectively, on the short-leg side. The 2 types were classified into 3 subtypes (A, B, and C) according to the severity of the pelvic obliquity (0°-3°, 3°-6°, and >6°). Angles of inclination of pelvic obliquity postoperatively, anteversions, and inclinations (abduction angle) for acetabular components were measured after total hip arthroplasty. Increased inclination (mean, 8.79°) was observed in type 1C, where the angle of inclination to pelvic obliquity postoperatively was minimally corrected. This increase may lead to cup instability. Rebalancing the pelvis in these cases with preoperative skeletal traction and/or sufficient release of hip contractures may be necessary. A correction of the mean inclination of the cup by 8.79° is required.

Function and quality of life in patients with recurvatum deformity after primary total knee arthroplasty: a review of our joint registry.

The aim of this paper is to assess function and quality of life in patients with recurvatum at 2 years after primary total knee arthroplasty. This prospective study involves 2587 total knee arthroplasty from 2004 to 2008 with 2-year follow-up. Patients' demographics, diagnosis, implants, range of motion, laxity, and knee and SF-36 scores were recorded. Recurvatum deformity of 0°, 1° to 5°, 6° to 10°, and more than 10° were classified as grades 0, 1, 2, and 3, respectively. Grade 1 had similar functional scores to grade 0 but significantly better SF1, SF4, SF5, and SF8 when compared with grades 2 and 3. Patients with mediolateral translation of more than 5 mm were more likely to have grades 2 and 3 recurvatum (P = .01), indicating global laxity. Postoperative recurvatum of more than 5° significantly impacts function and quality of life of patients.

Radiological predictive factors in the healing of displaced intracapsular hip fractures. A clinical study of 404 cases.

BACKGROUND: Fracture healing complications occur in approximately a third of displaced intracapsular hip fractures treated by reduction and internal fixation. Various radiographic features of the fracture have been used to estimate the risk of fracture healing complications. AIMS: To determine which radiographic features of a displaced intracapsular hip fracture were the most reliable in predicting fracture re-displacement after internal fixation. METHODS: The pre-operative radiographs for 404 patients with a displaced intracapsular hip fracture treated by reduction and internal fixation were classified using five different variables. These were a direct measurement of trochanteric shortening and fracture shortening, a ratio of fracture displacement, the Garden grade and an alternative interpretation of the Garden grading. Inter-observer reliability of the various classifications was also studied. These observations were related to the later occurrence of fracture displacement or non-union. RESULTS: Only trochanteric shortening had an acceptable degree of inter-observer variation and this was also the most predictive of fracture re-displacement. The ratio method and fracture shortening were also related to fracture healing complications. Using the traditional Garden grading equal numbers of grade III and IV fractures healed but an alternative interpretation of the Garden grading showed some relationship to the development of non-union. CONCLUSIONS: A direct measurement of shortening of the femur is the most reliable predictor of failure of the fracture to heal.

Developmental dysplasia of the hip: is acetabular retroversion a crucial factor?

OBJECTIVE: The objective of this study was to investigate a possible relation between congenital hip dysplasia and acetabular retroversion and to explore the eventual influence of the latter in the surgical decision for periacetabular osteotomy. MATERIALS AND METHODS: We assessed the classical morphological characteristics of both hips, with an additional newly described retroversion index. The study was conducted in 174 patients with uni- or bilateral congenital hip dysplasia having undergone unilateral (153 patients) or bilateral (21 patients) periacetabular osteotomy when respectively one or both dysplastic hips remained symptomatic. RESULTS: In the group of operated hips (195 hips in total), 53% of the acetabuli were anteverted, 42% retroverted, and 5% neutral orientations. The group of nonoperated hips (153 hips) included 24% normal hips, 22% hips with normal coverage but retroverted, 35% dysplastic hips with anteverted or neutral orientation, and 19% dysplastic retroverted hips. Comparing the two hips in the subgroup of patients in whom the operated and nonoperated sides were both dysplastic failed to demonstrate statistically significant difference in the mean retroversion index. However, all the other variables measured were significantly different; with the operated side more dysplastic. Comparing the two hips in the other subgroups showed that acetabular retroversion was nearly always bilateral and symmetrical, even in presence of unilateral congenital dysplasia. DISCUSSION: Our data suggest that the presence of acetabular retroversion is probably independent of the congenital hip dysplasia and that this abnormality seems at best a secondary factor in the appearance of dysplastic hip symptoms. LEVEL OF EVIDENCE: Level IV, retrospective diagnostic study.

Clasificación de las fracturas de la extremidad distal del radio dentro del medio laboral / Classification of distal radius fractures in the occupational setting

Desde que Abraham Colles describió la primera fractura del radio distal son muchas las clasificaciones utilizadas para establecer unas pautas de tratamiento y establecer el pronóstico de la fractura. La mayoría de las clasificaciones se basan en el grado de conminución, afectación articular, grado de desplazamiento o en el mecanismo de producción. Presentamos una nueva clasificación, adaptada al medio laboral, que valora el tipo de fractura, la gravedad objetiva y el desplazamiento de los fragmentos de una forma sencilla y eficaz, que se correlaciona con los criterios estabilidad de la misma y define la pauta a seguir en el tratamiento de la lesión en estudio

Since Abraham Colles first described distal radius fracture, many classifications have been used to define fracture treatment and prognosis. Most such classifications are based on the degree of comminution, joint involvement, degree of displacement, or mechanism of fracture. We present a new classification, adapted to the occupational setting, that assesses the type of fracture, its objective severity and fragment displacement in a simple and effective manner, in correlation to the fracture stability criteria, and defining the approach to treatment

The sulcus angle and malalignment of the extensor mechanism of the knee.

Anterior knee pain due to dysplasia of the extensor mechanism is common. We have studied 137 knees (103 patients) in order to identify a rapid and reproducible radiological feature which would indicate the need for further analysis. Overall, 67 knees (49%) had at least one radiological abnormality; 70 (51%) were considered normal. There were five cases of Dejour type-3 dysplasia of the femoral trochlea, nine of type-2 and 12 of type-1. There were 49 cases of patella alta and five of patella infera. Four knees had an abnormal lateral patellofemoral angle (patellar tilt), and in 15 knees there was more than one abnormality. Classification of trochlear dysplasia was difficult and showed poor reproducibility. This was also true for the measurement of the lateral patellofemoral angle. Patellar height was more easily measured but took time. The sulcus angle is an easily and rapidly measurable feature which was reproducible and was closely related to other features of dysplasia of the extensor mechanism. The finding of a normal sulcus angle suggested that seeking other radiological evidence of malalignment of the extensor mechanism was unlikely to reveal additional useful information. The severity of other features of dysplasia of the extensor mechanism correlated with increasing sulcus angle.

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.

Classification of femoral abnormalities in total hip arthroplasty.

Bony abnormalities of the femur can significantly complicate total hip arthroplasty both for the primary and revision operations. No standard nomenclature exists for the description of these femoral abnormalities. A classification system is presented to standardize nomenclature, assist in preoperative planning, and to assist in the reporting of these defects.