髖膝文獻(xiàn)精譯薈萃（第三期）

Patella Baja After Total Knee Arthroplasty: Is It Really Patella Baja?

In the prosthetic knee, narrowing of the space between the patella and the tibial polyethylene can be due to distal positioning of the patella or to a proximal transfer of the joint line. In the former case, one is dealing with patella baja. In the latter case, the patella is in its normal position relative to the femur, a situation we call pseudo–patella baja. The therapeutic options for patella baja and pseudo–patella baja are different because the former is due to a short patellar tendon, and the latter is due to a raised joint line. Eversion of the extensor mechanism during revision surgery may be more challenging with true patella baja compared with pseudopatella baja. It is important not to attempt to detect true patella baja with either the Blackburne-Peel or the Caton-Deschamps ratio in the setting of a prosthetic knee because these ratios are affected adversely by the position of the joint line.

文獻(xiàn)出處：Grelsamer RP.Patella baja after total knee arthroplasty: is itreally patella baja?J Arthroplasty. 2002 Jan;17(1):66-9.                                           

Acetabular andFemoral Anteversions in Standing Position are Outside the Proposed Safe ZoneAfter Total Hip Arthroplasty

Background: Although most hip dislocations occur in either standing or sitting position, the safe zone for implant position is defined for the supine position. Our goal was to determine preoperative and postoperative pelvis and hip orientations and whether the safe zone defined in supine position can be used to assess standing radiographs.

Methods: Preoperative and postoperative three-dimensional EOS images were assessed in 66 total hip arthroplasty patients. None of the patients had dislocation within the follow-up period (12-36 months). The acetabular anteversion (both anterior pelvic plane [APP] and patient functional plane) and the femoral anteversion were measured. The sacral slope, pelvic version, pelvic inclination, and pelvic incidence were also measured.

Results: Acetabular anteversion increased postoperatively in both APP and patient functional plane (P ＜.001). Femoral neck anteversion decreased postoperatively (P=.0942）. Sacral slope was 42.4° (-25.9° to 24°）preoperatively compared with 40.3° (-4.1° to 64.2°） postoperatively (P=.013）. Pelvic version changed from 15.2° (-10.4° to 43.8°) to 17.2° (-6° to 46.7°；P=0.008). Pelvic inclination was 1.12° (-25.9° to 24°） before total hip atptnroplasty and -1.2° (-40.7° to 23.4°) postoperatively (P=.005).

Conclusion: The acetabular and femoral implant orientations in standing position reside out of the safe zone in most patients. The APP is not vertical in standing position in most patients due to anterior or posterior pelvic tilt. The proposed safe zone in supine position may not be a useful measure in the assessment of standing radiographs of patients with significant anterior or posterior pelvic tilt.

文獻(xiàn)出處：Lazennec JY, Thauront F, Robbins CB, Pour AE. Acetabular and Femoral Anteversionsin Standing Position are Outside the Proposed Safe Zone After Total Hip Arthroplasty. J Arthroplasty. 2017 Nov;32(11):3550-3556.

Reduction Osteotomy VS Pie-Crust Technique as Possible Alternatives for Medial Release in Total Knee Arthroplasty and Compared in a Prospective Randomized Controlled Trial

Background: To compare the gap change between the pie-crust technique and reduction osteotomy to determine their effects on flexion and extension gaps and their success rates in achieving ligament balancing during total knee arthroplasty.

Methods: In a prospective randomized controlled trial, 106 total knee arthroplasties were allocated to each group with 53 cases. If there was a narrow medial gap with an imbalance of ≥3 mm after the initial limited medial release, either reduction osteotomy or pie-crust technique was performed. The changes of extension and flexion medial gaps along with the success rate of mediolateral balancing were compared. 

Results: There was a significant difference in the change of medial gap in knee extension with mean changes of 3.5 ± 0.5 mm and 2.3 ± 0.8 mm in the reduction osteotomy and pie-crust groups, respectively (P < .001). For flexion gap, greater change was found in the pie-crust group compared with the reduction osteotomy group; the mean medial gap changes in knee flexion were 1.1 ± 0.5 mm and 2.3 ± 1.2 mm in the reduction osteotomy and pie-crust groups, respectively. The success rates were 90.6% and 67.9% in reduction osteotomy and pie-crust groups, respectively (P=.007). 

Conclusion: As an alternative medial release method, reduction osteotomy was more effective in extension gap balancing, and pie-crust technique was more effective in flexion gap balancing. The overall success rate of mediolateral ligament balancing was higher in the reduction osteotomy group than in the pie-crust group.

文獻(xiàn)出處：Ahn JH, Yang TY, Lee JY. Reduction Osteotomy vs Pie-Crust Technique as Possible Alternatives for Medial Release in Total Knee Arthroplasty and Compared in a Prospective Randomized Controlled Trial. J Arthroplasty. 2016Jul;31(7):1470-5.

Valgus Slipped Capital Femoral Epiphysis: Pathophysiology of Motion and Results of Intracapsular Realignment

OBJECTIVES: The purpose of this study was to report (1) a different but specific pattern of impingement in hips involved with valgus slipped capital femoral epiphysis (valgus SCFE) and (2) the results of surgical treatment using intracapsular realignment techniques.

DESIGN: Case series.

SETTING: Multiple academic centers.

PATIENTS: Six patients with 8 involved hips referred for valgus alignment of proximal femoral epiphysis (valgus SCFE).

INTERVENTION: Intracapsular realignment osteotomy combined with periacetabular osteotomy if needed.

MAIN OUTCOMEMEASUREMENT: The clinical and radiographical results and pathophysiology of motion.

RESULTS: Eight hips in 6 patients were treated with subcapital (5 hips) or femoral neck (3 hips) osteotomy for realignment. The medially prominent metaphysis created an inclusive impingement at the anterior acetabular wall, whereas the high coxa valga favored impacting impingement at the posterior head-neck junction. The mean preoperative epiphyseal-shaft angle of 110.5 (range 90-125 degrees) was reduced to 62 degrees (range 55-70 degrees) postoperatively. At the last follow-up, all but 1 hip were pain-free and impingement-free, with normal range of motion. One hip was replaced after repeated attempts of correction. The overall hip functional result using modified Merle d'Aubigne scoring system was excellent in 5 hips (18-16 points), good in 2 hips (16-15 points), and poor in 1 hip (6 points).

CONCLUSIONS: Impingement in valgus SCFE deformity is specific and complex. Anatomical realignment can lead to favorable results by the restoration of normal morphology and impingement-free range of motion.

文獻(xiàn)出處：Kalhor M,Gharanizadeh K, Rego P, Leunig M, Ganz R. Valgus Slipped Capital Femoral Epiphysis: Pathophysiology of Motion and Results of Intracapsular Realignment. J Orthop Trauma. 2018 Feb;32 Suppl 1:S5-S11.

Lateral Acetabular Coverage Predicts the Size of the Hip Labrum

BACKGROUND: Bony morphological abnormalities of the hip joint are often accompanied by adaptive soft tissue changes. These adaptive changes, if better understood and characterized, may serve to inform clinical decision making.

PURPOSE: To investigate the correlation between the size of the hip labrum and lateral acetabular coverage in patientsat our hip preservation clinic.

METHODS: A cohort of 236 patients seen at a dedicated hip preservation service between June 2013 and June 2015 were retrospectively analyzed. Patients were grouped according to the degree of acetabular coverage, as measured by the lateral center-edge angle (LCEA): normal acetabular coverage (25°-39.9°), acetabular overcoverage (≥40°), borderline dysplasia (20°-24.9°), and frank dysplasia (<20°). Preoperative magnetic resonance imaging was utilized to measure the length ofthe labrum at 3 locations: laterally, anteriorly, and anteroinferiorly.

RESULTS: Frankly dysplastic and borderline dysplastic hips exhibited larger values of labral length at all locations when compared with hips with normal acetabular coverage (P < .001) or acetabular overcoverage (P < .001). Interestingly, mean labral length values in frank dysplasia were statistically similar to corresponding measurements in borderline dysplasia. In hips with frank dysplasia, borderline dysplasia, or normal acetabular coverage, labral length was consistently greatest at the lateral labrum and correspondingly lowest at the anteroinferior labrum (P < .001). In hips with acetabular overcoverage, labral length did not vary significantly between the lateral, anterior, and anteroinferior locations. Multivariate analyses confirmed LCEA to be the strongest predictor of labral length, irrespective of measurement location.

CONCLUSION: Patients with borderline dysplasia and frank dysplasia exhibited increased values of labral length in the weight bearing zone, potentially indicating a compensatory reaction to the lack of bony coverage. Labral length may serve as an instability marker and inform clinical decision making for patients with borderline dysplasia.

文獻(xiàn)出處：Garabekyan T, Ashwell Z, Chadayammuri V, Jesse MK, Pascual-Garrido C, Petersen B, Mei-Dan O. Lateral Acetabular Coverage Predicts the Size of the Hip Labrum. Am J Sports Med. 2016 Jun;44(6):1582-9. 

Fracture at theIschio-Pubic Junction After Periacetabular Osteotomy in the AdolescentPopulation

INTRODUCTION: The Ganz periacetabular osteotomy (PAO) is a well-accepted surgical intervention for hip dysplasia. In the adolescent population it is performed in patients who are skeletally mature with symptoms related to acetabular dysplasia. Redistribution of stresses through the hemipelvis after PAO can lead to a fracture at the ischio-pubic junction (IPJ).

METHODS: This is an IRB-approved, retrospective analysis of adolescent patients treated with a PAO for acetabular dysplasia from 1999 to 2012 at a single institution. Radiographic measurements were performed to include the lateral center-edge angle, Sharp acetabular index, and acetabular index of the weight-bearing zone. These were measured preoperatively and at 6-weeks and 1 year postoperatively from a standing anterior posterior pelvis radiograph. Postoperative modified Harris hip scores (mHHS) were also analyzed. Patients over the age of 21 at time of surgery and those with <2 years of follow-up were excluded.

RESULTS: One hundred sixty-six patients (187 operated hips) at an average age of 15.6±2.5 were included. Twelve (6.4%) fractures at the IPJ were identified in 12 patients. Seven were identified on the initial postoperative films, whereas 5 were identified after the 6-week visit. Seven (58.3%) fractures had an associated superior posterior ramus nonunion. Six (50%) healed by 2 years after surgery; the remaining 6 (50%) went on to nonunion. Compared with those without a fracture, there was no significant difference in preoperative, 6 weeks postoperative, and final center-edge angle (P=0.94, 0.29, 0.27), Sharp acetabular index (P=0.95, 0.38, 0.16), or AIBWZ (P=0.37, 0.21, 0.54). There was no difference in postoperative mean modified Harris hip scores (P=0.63). Analysis of predisposing factors demonstrated that patients with Charcot-Marie-Tooth (CMT) disease were more likely to develop an IPJ fracture (P=0.001). Patients with an IPJ fracture were older (17.1 vs. 15.5, P=0.05). There was no difference based on patient sex (P=0.22). 

DISCUSSION AND CONCLUSIONS: The incidence of fracture at the IPJ after PAO in the adolescent population is 6.4% with some occurring at the time of surgery. These fractures are also associated with a nonunion at the superior posterior ramus cut and an underlying diagnosis of Charcot-Marie-Tooth. These fractures are not clinically significant and in this series did not merit further intervention when identified.

文獻(xiàn)出處：Swann M, Sucato DJ, Romero J, Podeszwa DA.Fracture at the Ischio-Pubic Junction After Periacetabular Osteotomy in the Adolescent Population. J Pediatr Orthop. 2017Mar;37(2):127-132.

Screening inDevelopmental Dysplasia of the Hip

Screening for Developmental Dysplasia of the Hip (DDH) is a controversial subject. Screening may be by universal neonatal clinical examination (Ortolani or Barlow manoeuvres) with the addition of sonographic imaging of the hip (selective 'at risk' hips or universal screening in the neonate). In the UK, the NIPE guidelines recommend universal neonatal clinical assessment of the hip joints, a General Practitioner 6-8 week clinical 'hip check' and assessment clinically with sonographic imaging at 4-6 weeks for certain 'at risk' hips for pathological DDH. The effectiveness and difficulties arising from the UK current screening policy (clinical and sonographic) are highlighted. The purpose of the review was to assess the risk factors and efficacy of diagnostic methods in DDH, based on longitudinal cohort studies of 10 years or more.

CONCLUSION: Hip screening in DDH does not meet most of the World Health Organisation's criteria for an effective screening programme and should only be considered as surveillance due to its low sensitivity and positive predictive value (PPV). There is a significant risk of over diagnosis and over treatment. There is no International consensus on screening in DDH. Pathological DDH is mainly a female condition and 'at risk'/General Practitioner screening identifies few pathological cases in male subjects. The General Practitioner 6-8 week 'hip check' has a very low PPV for pathological DDH and is of doubtful value in screening and diagnosis. Unilateral limitation of hip abduction is a time dependent and useful clinical sign in the diagnosis of pathological DDH. The majority of the previously considered 'at risk' factors are not true risk factors with little or no association with pathological DDH.

文獻(xiàn)出處：PatonRW. Screening in Developmental Dysplasia of the Hip (DDH). Surgeon. 2017.15(5): 290-296.