Periazetabuläre Osteotomie nach Ganz

The Bernese periacetabular osteotomy (PAO) is a surgical technique for the treatment of (1) hip dysplasia and (2) femoroacetabular impingement due to acetabular retroversion. The aim of the surgery is to prevent secondary osteoarthritis by improvement of the hip biomechanics. In contrast to other pelvic osteotomies, the posterior column remains intact with this technique. This improves the inherent stability of the acetabular fragment and thereby facilitates postoperative rehabilitation. The birth canal remains unchanged. Through a shortened ilioinguinal incision, four osteotomies and one controlled fracture around the acetabulum are performed. The direction of acetabular reorientation differs for both indications while the sequence of the osteotomies remains the same. This surgical approach allows for a concomitant osteochondroplasty in the case of an aspherical femoral head-neck junction. The complication rate is relatively low despite the complexity of the procedure. The key point for a successful long term outcome is an optimal reorientation of the acetabulum for both indications. With an optimal reorientation and a spherical femoral head, the cumulative survivorship of the hip after 10 years is 80–90?%. For the very first 75 patients, the cumulative 20-year survivorship was 60?%. The preliminary evaluation of the same series at a 30-year follow-up still showed a survivorship of approximately 30?%. The PAO has become the standard procedure for the surgical therapy of hip dysplasia in adolescents and adults.     

Perfusion of the femoral head during surgical dislocation of the hip. Monitoring by laser Doppler flowmetry

We used laser Doppler flowmetry (LDF) with a high energy (20 mW) laser to measure perfusion of the femoral head intraoperatively in 32 hips. The surgical procedure was joint debridement requiring dislocation or subluxation of the hip. The laser probe was placed within the anterosuperior quadrant of the femoral head. Blood flow was monitored in specific positions of the hip before and after dislocation or subluxation. With the femoral head reduced, external rotation, both in extension and flexion, caused a reduction of blood flow. During subluxation or dislocation, it was impaired when the posterosuperior femoral neck was allowed to rest on the posterior acetabular rim. A pulsatile signal returned when the hip was reduced, or was taken out of extreme positions when dislocated. After the final reduction, the signal amplitudes were first slightly lower (12%) compared with the initial value but tended to be restored to the initial levels within 30 minutes. Most of the changes in the signal can be explained by compromise of the extraosseous branches of the medial femoral circumflex artery and are reversible. Our study shows that LDF provides proof for the clinical observation that perfusion of the femoral head is maintained after dislocation if specific surgical precautions are followed.     

Efficiency and Accuracy of Bernese Periacetabular Osteotomy for Adult Hip Dysplasia

Bernese periacetabular osteotomy (PAO) has several advantages dealing with adolescents and adults acetabular dysplasia. The authors introduced the details and steps performing PAO, with attached video and schematic diagram which demonstrates a perfect PAO in efficiency and accuracy. The patient is an 18‐year‐old girl, complaining hip pain on the left side for 6 months. Physical examination shows normal gait and range of motion (ROM) of the left hip. Pelvic anteroposterior X‐ray shows acetabular dysplasia on the left, and post operation on the right. She is very satisfied with the PAO on the right one year before, so we recommend PAO for the left hip dysplasia again. The key point of PAO includes 4 cuts: ischial cut, pubic cut, acetabular roof cut, and quadrilateral bone cut, and the four cuts should be accomplished accurately. Then the acetabular fragment should be turned to ideal position with the lateral CE angle (LCE) > 25°, the Tönnis acetabular angle 0°, the anterior CE angle (ACE) > 20°, good congruence joint space, and with the hip center medialized slightly. At lastly the acetabular fragment is fixed with proper nails and instruments. The patient is very happy to the surgery with no hip pain, with normal gait, ROM, and Harris hip scores (HHS). In summary, PAO is a relative new and efficient procedure for adult hip dysplasia, requiring accurate techniques. Cadaveric practice and familiar with the local anatomy can help the surgeon overcome the learning curve quickly.     

An incomplete periacetabular osteotomy for treatment of neuromuscular hip dysplasia

Standard innominate osteotomies that are recommended for treatment of the typical form of developmental dysplasia of the hip are not recommended for dysplasia associated with neuromuscular disorders. A periacetabular osteotomy that permitted accurate correction of the posterolateral acetabular deficiency was done on 40 patients (50 hips). The purpose of this study was to present the surgical technique, to evaluate whether it can improve acetablular dysplasia, and to provide stable hips. The patients had a mean age of 9.5 years at the time of surgery. The medial cortex of the ilium was left intact, whereas the supraacetabular and retroacetabular cancellous bone, and posterolateral cortical bone were cut. The posterior cut extended down to the triradiate cartilage, or through its former site, respectively. Forty-one hips were evaluated at a mean followup of 5.3 years (range, 2-11.7 years) after surgery. The mean acetabular index improved from 32 degrees preoperatively to 12 degrees at followup. The mean migration percentage improved from 77% to 13%. A redislocation or unstable hip occurred in two patients. According to caregivers, surgery improved personal care, positioning, and comfort. This osteotomy decreases the radius of the elongated acetabulum, provides coverage by articular cartilage particularly at the posterolateral aspect of the acetabulum, and preserves the entire medial wall of the ilium.     

Effects of different pelvic osteotomies on acetabular morphology in developmental dysplasia of hip in children

Developmental dysplasia of hip seriously affects the health of children, and pelvic osteotomy is an important part of surgical treatment. Improving the shape of the acetabulum, preventing or delaying the progression of osteoarthritis is the ultimate goal of pelvic osteotomies. Re-directional osteotomies, reshaping osteotomies and salvage osteotomies are the three most common types of pelvic osteotomy. The influence of different pelvic osteotomy on acetabular morphology is different, and the acetabular morphology after osteotomy is closely related to the prognosis of the patients. But there lacks comparison of acetabular morphology between different pelvic osteotomies, on the basis of retrospective analysis and measurable imaging indicators, this study predicted the acetabular shape after developmental dysplasia of the hip pelvic osteotomy in order to help clinicians make reasonable and correct decisions and improve the planning and performance of pelvic osteotomy.     

Does Previous Reconstructive Surgery Influence Functional Improvement and Deformity Correction After Periacetabular Osteotomy?

Background  

The Bernese periacetabular osteotomy (PAO) is commonly used to surgically treat residual acetabular dysplasia. However, the degree to which function and radiographic deformity are corrected in patients with more severe deformities that have undergone previous reconstructive pelvic or femoral osteotomies is unclear.     

Patellar blood flow during knee arthroplasty surgical exposure: Intraoperative monitoring by laser doppler flowmetry.

Patellofemoral complications following knee arthroplasty are a well-known problem. Patellar ischemia has been suspected to be causative for fracture, anterior knee pain, and patella component failure. The purpose of this study was to assess the influence of knee arthroplasty surgical dissection on patellar blood flow. Patellar blood flow was measured by means of intraosseous laser Doppler flowmetry (LDF) in 10 patients undergoing total knee arthroplasty by a standard medial parapatellar approach. The initial blood flow was 121.6 +/- 114.7 AU. The signal significantly decreased by 71% (p = 0.0051) when the knee was flexed and lost the pulsatile signal pattern in 80%. After arthrotomy, the signal was 100.1 +/- 120.3 AU in extension. The lowest signal was found in flexion and eversion of the patella (mean, 18 +/- 10.7 AU) and all signals lost pulsatility. As compared to the initial values, completion of the soft tissue dissection did not lead to a significant change of the blood flow signal (121.3 +/- 104.8; p = 0.6835). Flexion of the knee joint markedly reduced patellar perfusion. Standard medial parapatellar approach did not significantly change patellar blood flow. This study does not support the theory of postoperative patellar ischemia as a cause of anterior knee pain or patellofemoral problems.     

Prominent Anterior Inferior Iliac Spine Morphologies Are Common in Patients with Acetabular Dysplasia Undergoing Periacetabular Osteotomy

BackgroundThe anterior inferior iliac spine (AIIS) prominence is increasingly recognized in the setting of femoroacetabular impingement (FAI). The AIIS prominence may contribute to decreased hip flexion after acetabular reorientation in patients with acetabular dysplasia. AIIS morphologies have been characterized in numerous populations including asymptomatic, FAI, and athletic populations, but the morphology of the AIIS in patients with symptomatic acetabular dysplasia undergoing periacetabular osteotomy (PAO) has not been studied. In acetabular dysplasia, deficiency of the anterosuperior acetabular rim is commonly present and may result in the AIIS being positioned closer to the acetabular rim. Understanding morphological variation of the AIIS in patients with symptomatic dysplasia, and its relationship to dysplasia subtype and severity may aid preoperative planning, surgical technique, and evaluation of postoperative issues after PAO.Questions/purposesIn this study, we sought to determine: (1) the variability of AIIS morphology types in hips with symptomatic acetabular dysplasia and (2) whether the differences in the proportion of AIIS morphologies are present between dysplasia pattern and severity subtypes.MethodsUsing our hip preservation database, we identified 153 hips (148 patients) who underwent PAO from October 2013 to July 2015. Inclusion criteria for the current study were (lateral center-edge angle [LCEA] < 20°), Tönnis Grade of 0 or 1 on plain AP radiographs of the pelvis, preoperative low-dose CT scan, and no prior surgery, trauma, neuromuscular, ischemic necrosis, or Perthes-like deformity. A total of 50 patients (50 hips) with symptomatic acetabular dysplasia undergoing evaluation for surgical planning of PAO remained for retrospective evaluation; we used these patients’ low-dose CT scans for analysis. The median (range) age of patients in the study was 24 years (13 to 49). Ninety percent (45 of 50) of the hips were in female patients, whereas 10% (5 of 50) were in male patients. The morphology of the AIIS was classified on three-dimensional CT reconstructions according to a previously published classification to define the relationship between the AIIS and the acetabular rim. The morphology of the AIIS was classified as Type I (AIIS well proximal to acetabular rim), Type II (AIIS extending to level of acetabular rim), or Type III (AIIS extending distal to acetabular rim). Acetabular dysplasia subtype was characterized according to a prior protocol as either predominantly an anterosuperior acetabular deficiency, a posterosuperior acetabular deficiency, or a global acetabular deficiency. Acetabular dysplasia severity was distinguished as mild (LCEA 15° to 20°) or moderate/severe (LCEA < 15°). To answer our first question, regarding the proportions of each AIIS morphology in the dysplasia population, we calculated proportions and 95% CI estimates. To answer our second question, regarding the proposition of AIIS type between subtypes of dysplasia type and severity, we used a chi-square test or Fisher’s exact test to compare categorical variables. A p value of < 0.05 was considered significant.ResultsSeventy-two percent (36 of 50; 95% CI 58% to 83%) of patients had a Type II or III AIIS morphology. Type I AIIS morphology was found in 28% of patients (14 of 50; 95% CI 18% to 42%), Type II AIIS morphology in 62% (31 of 50; 95% CI 48% to 74%), and Type III AIIS/morphology in 10% (5 of 50; 95% CI 4% to 21%). A Type I AIIS was seen in seven of 15 of patients with anterosuperior acetabular deficiency, three of 18 of patients with global deficiency, and four of 17 patients with posterosuperior deficiency (p = 0.08). There was no difference in the variability of AIIS morphologies between the different subtypes of acetabular dysplasia pattern and no difference in AIIS morphology variability between patients with mild versus moderate/severe dysplasia.ConclusionsThe morphology of the AIIS in patients with acetabular dysplasia is commonly prominent, with 72% of hips having Type II or Type III morphologies.Clinical RelevanceThe AIIS is often prominent in patients with acetabular dysplasia undergoing PAO, regardless of dysplasia pattern or severity. Prominent AIIS morphologies may affect hip flexion ROM after acetabular reorientation. AIIS morphology is a variable that should be considered during preoperative planning for PAO. Future studies are needed to assess the clinical significance of a prominent AIIS on intraoperative findings and postoperative status after PAO.     

Does Tranexamic Acid Reduce Blood Loss and Transfusion Requirements Associated With the Periacetabular Osteotomy?

Background

Tranexamic acid (TXA) has shown safety and efficacy in reducing blood loss associated with various surgical procedures. However, to our knowledge there are no studies evaluating the effect of TXA on blood loss and transfusion requirements associated with periacetabular osteotomy (PAO).

Questions/purposes

The main purpose of this study is to determine whether TXA reduces blood loss and transfusion use in patients undergoing PAO for symptomatic acetabular dysplasia. Our secondary purpose was to compare the frequency of symptomatic thromboembolic events between patients undergoing surgery with and without TXA.

Methods

A consecutive series of 100 periacetabular osteotomies performed by one surgeon was reviewed to compare the groups immediately before and after implementation of routine use of tranexamic acid (two retrospective cohorts). TXA dosing followed an established protocol with a standard dose of 1 g infused intravenously during 10 minutes before skin incision and an additional 1 g intravenously at wound closure. Outcome measures include total estimated blood loss perioperatively and transfusion requirements. Total estimated blood loss was calculated using a formula built from the National Surgical Quality Improvement Program data regarding surgical blood loss.

Results

The mean perioperative total estimated blood loss was less in the patients receiving TXA compared with blood loss in patients who did not receive TXA (706 mL versus 1021 mL; p < 0.001; 95% CI, −495 to −134). Twenty-six (52%) of the 50 patients who did not receive TXA had postoperative blood transfusions compared with 15 (30%) of 50 who received TXA (odds ratio, 0.395; 95% CI, 0.174–0.899; p = 0.0414). No symptomatic deep vein thromboses or symptomatic pulmonary emboli were identified in either group.

Conclusions

TXA reduces estimated blood loss and the frequency of transfusions in patients undergoing PAO for treatment of symptomatic acetabular dysplasia. Future prospective studies should confirm our findings to determine whether patients undergoing PAO should receive routine perioperative TXA.

Level of Evidence

Level III, therapeutic study.     

Periacetabular Osteotomy Provides Higher Survivorship Than Rim Trimming for Acetabular Retroversion

Background

Acetabular retroversion can cause impaction-type femoroacetabular impingement leading to hip pain and osteoarthritis. It can be treated by anteverting periacetabular osteotomy (PAO) or acetabular rim trimming with refixation of the labrum. There is increasing evidence that acetabular retroversion is a rotational abnormality of the entire hemipelvis and not a focal overgrowth of the anterior acetabular wall, which favors an anteverting PAO. However, it is unknown if this larger procedure would be beneficial in terms of survivorship and Merle d’Aubigné scores in a midterm followup compared with rim trimming.

Questions/purposes

We asked if anteverting PAO results in increased survivorship of the hip compared with rim trimming through a surgical hip dislocation in patients with symptomatic acetabular retroversion.

Methods

We performed a retrospective, comparative study evaluating the midterm survivorship of two matched patient groups with symptomatic acetabular retroversion undergoing either anteverting PAO or acetabular rim trimming through a surgical hip dislocation. Acetabular retroversion was defined by a concomitantly present positive crossover, posterior wall, and ischial spine sign. A total of 279 hips underwent a surgical intervention for acetabular retroversion at our center between 1997 and 2012 (166 periacetabular osteotomies, 113 rim trimmings through surgical hip dislocation). A total of 99 patients (60%) were excluded from the PAO group and 56 patients (50%) from the rim trimming group because they had any of several prespecified conditions (eg, dysplasia or pediatric conditions 61 [37%] for the PAO group and two [2%] for the rim trimming group), matching (10 [6%]/10 [9%] hips), deficient records (10 [6%]/13 [12%] hips), or the patient declined or was lost to followup (18 [11%]/31 [27%] hips). This left 67 hips (57 patients) that underwent anteverting PAO and 57 hips (52 patients) that had acetabular rim trimming. The two groups did not differ in terms of age, sex, body mass index, preoperative ROM, preoperative Merle d’Aubigné-Postel score, radiographic morphology of the acetabulum (except total and anterior acetabular coverage), alpha angle, Tönnis grade of osteoarthritis, and labral and chondral lesions on the preoperative MRI. During the period in question, we generally performed PAO from 1997 to 2003. With the availability of surgical hip dislocation and labral refixation, we generally performed rim trimming from 2004 to 2010. With growing knowledge of the underlying pathomorphology, anteverting PAOs became more common again around 2007 to 2008. A minimum followup of 2 years was required for this study. Failures were included at any time. The median followup for the anteverting PAO group was 9.5 years (range, 2–17.4 years) and 6.8 years (range, 2.2–10.5 years) for the rim trimming group (p < 0.001). Kaplan-Meier survivorship analysis was performed using the following endpoints at 5 and 10 years: THA, radiographic progression of osteoarthritis by one Tönnis grade, and/or Merle d’Aubigné-Postel score < 15 points.

Results

Although the 5-year survivorship of the two groups was not different with the numbers available (86% [95% confidence interval {CI}, 76%–94%] for anteverting PAO versus 86% [95% CI, 76%–96%] for acetabular rim trimming), we found increased survivorship at 10 years in hips undergoing anteverting PAO for acetabular retroversion (79% [95% CI, 68%–90%]) compared with acetabular rim trimming (23% [95% CI, 6%–40%]) at 10 years (p < 0.001). The drop in the survivorship curve for the acetabular rim trimming through surgical hip dislocation group started at Year 6. The main reason for failure was a decreased Merle d’Aubigné score.

Conclusions

Anteverting PAO may be the more appropriate treatment for hips with substantial acetabular retroversion. This may be the result of reduction of an already smaller lunate surface of hips with acetabular retroversion through rim trimming. However, rim trimming may still benefit hips with acetabular retroversion in which only one or two of the three signs are positive. Future randomized studies should compare these treatments.

Level of Evidence

Level III, therapeutic study.

     

Current concept in dysplastic hip arthroplasty: Techniques for acetabular and femoral reconstruction

Adult patients with developmental dysplasia of the hip develop secondary osteoarthritis and eventually end up with total hip arthroplasty (THA) at younger age. Because of altered anatomy of dysplastic hips, THA in these patients represents technically demanding procedure. Distorted anatomy of the acetabulum and proximal femur together with conjoined leg length discrepancy present major challenges during performing THA in patients with developmental dysplasia of the hip. In addition, most patients are at younger age, therefore, soft tissue balance is of great importance (especially the need to preserve the continuity of abductors) to maximise postoperative functional result. In this paper we present a variety of surgical techniques available for THA in dysplastic hips, their advantages and disadvantages. For acetabular reconstruction following techniques are described: Standard metal augments (prefabricated), Custom made acetabular augments (3D printing), Roof reconstruction with vascularized fibula, Roof reconstruction with pedicled iliac graft, Roof reconstruction with autologous bone graft, Roof reconstruction with homologous bone graft, Roof reconstruction with auto/homologous spongious bone, Reinforcement ring with the hook in combination with autologous graft augmentation, Cranial positioning of the acetabulum, Medial protrusion technique (cotyloplasty) with chisel, Medial protrusion technique (cotyloplasty) with reaming, Cotyloplasty without spongioplasty. For femoral reconstruction following techniques were described: Distraction with external fixator, Femoral shortening through a modified lateral approach, Transtrochanteric osteotomies, Paavilainen osteotomy, Lesser trochanter osteotomy, Double-chevron osteotomy, Subtrochanteric osteotomies, Diaphyseal osteotomies, Distal femoral osteotomies. At the end we present author’s treatment method of choice: for acetabulum we perform cotyloplasty leaving only paper-thin medial wall, which we break during acetabular cup impacting. For femoral side first we peel of all rotators and posterior part of gluteus medius and vastus lateralis from greater trochanter on the very thin flake of bone. This method allows us to adequately shorten proximal femoral stump, with possibility of additional resection of proximal femur. Furthermore, several advantages and disadvantages of this procedure are also discussed.     

A computer simulation of rotational acetabular osteotomy for dysplastic hip joint: does the optimal transposition of the acetabular fragment exist?

For young patients who have early signs of coxarthrosis resulting from acetabular dysplasia, periacetabular osteotomies for correcting abnormal stress distribution can be useful for preventing the progression of the disease. However, it is difficult to confirm the optimal transposition of the osteotomized acetabular fragment. To deal with this problem, we devised a computer program to support preoperative planning. Hip images obtained by computed tomography were loaded into our program, and a three-dimensional voxel model was created. Then, osteotomy was simulated and the pressure distribution was analyzed with a rigid-body spring analysis (computational nonlinear mechanical analysis). The three-dimensional pressure distributions in seven dysplastic hips were evaluated before and after virtual rotational acetabular osteotomy. A peak pressure was calculated for every 5° of rotation of the acetabular fragment. The peak pressure decreased gradually and increased again afterward, indicating the optimal transposition of the acetabular fragment. The postoperative peak pressure decreased to about 40% in the most improved case. This program allows the hip joint mechanics to be evaluated easily so that the advantages and disadvantages of various surgical methods can be examined biomechanically prior to surgery.     

Blood perfusion and bone formation before and after minimally invasive periacetabular osteotomy analysed by Positron Emission Tomography combined with Computed Tomography

Purpose

Sufficient blood perfusion is essential for successful bone healing after periacetabular osteotomy (PAO). The purpose of this study was to quantify blood perfusion and bone formation before and after PAO analysed by positron emission tomography (PET) combined with computed tomography (CT).

Methods

Twelve dysplastic patients (nine women) were included consecutively in the study and all were operated upon by the senior author (KS). Median age was 33 (23–55) years. Initially, two patients were PET scanned in a pilot study to test our models for calculation of the physiological parameters. The following ten patients had their hip joints PET/CT scanned immediately before PAO and three to four weeks after. Oxygen-15-water was used to quantify blood perfusion and Flourine-18-fluoride was used to produce quantitative images interpreted as new bone formation in the acetabular fragment.

Results

The blood perfusion of the operated acetabulum before surgery was 0.07?±?0.02 ml/min/ml, and after surgery 0.19?±?0.03 ml/min/ml (p?=?0.0003). Blood perfusion of the non-operated acetabulum was 0.07?±?0.02 ml/min/ml before PAO and 0.07?±?0.02 ml/min/ml after surgery (p?=?0.47). The fluoride-clearance per volume bone of the operated acetabulum was 0.02?±?0.01 ml/min/ml preoperatively, and 0.06?±?0.01 ml/min/ml postoperatively (p?=?0.0005). Fluoride-clearance of the non-operated acetabulum was 0.01?±?0.01 ml/min/ml before PAO and 0.02?±?0.01 ml/min/ml after PAO (p?=?0.49).

Conclusion

Blood perfusion and new bone formation increased significantly in the acetabular fragment. Thus, the results of this study do not support the concern about surgically damaged vascularity after PAO.     

Increased intraarticular pressure reduces blood flow to the femoral head

Hemarthrosis leading to increased intracapsular pressure after an undisplaced femoral neck fracture is suspected to impair blood flow to the femoral head and may lead to osteonecrosis. We hypothesized that an increase of intraarticular pressure would reversibly decrease the blood flow to the femoral head. Eleven patients having surgical dislocations for treatment of femoroacetabular impingement were included in this study. Saline was injected into the intact intracapsular space while the blood flow to the femoral head was recorded using laser Doppler flowmetry. Injection of saline resulted in an increase in the intracapsular pressure. The injected volume of normal saline until disappearance of the pulsatile signal was on average 20 mL (range, 10-35 mL) with an average intraarticular pressure of 58 mm Hg (range, 25-88 mm Hg). Aspiration of the joint resulted in a return of the pulsatile flow. Hemarthrosis after undisplaced intracapsular fractures of the femoral neck are likely to cause an increase in intracapsular pressure. Decompression of the hematoma to reduce the intracapsular pressure is strongly advocated to optimize blood flow to the femoral head in acute fractures.     

A combination pelvic osteotomy for acetabular dysplasia in children

Several surgical procedures have been devised to increase acetabular coverage of the femoral head in children with dysplasia of the hip. In this report we describe an acetabuloplasty that combines the key aspects of the Pemberton and Salter osteotomies. It has been used at the Los Angeles Unit of the Shriners Hospital for Crippled Children since the late 1960's. To assess the results of this combination procedure, fifty hips in forty-four children were evaluated at an average of six years postoperatively. The average age at operation was 7.3 years, and 62 per cent of the patients had had prior surgery. Clinically, thirty-two hips in which there had been no or slight symptoms preoperatively remained unchanged, twelve that had had preoperative limitations improved, and six showed some deterioration in terms of slight loss of motion, mild pain, and a limp. Roentgenographically, acetabular dysplasia (as measured by the acetabular index and by the center-edge angle of Wiberg) improved in more than 90 per cent of the hips. The roentgenographic results were comparable with those obtained by innominate or pericapsular osteotomy. The combination osteotomy has the advantages of both the Pemberton procedure and the Salter operation and proved to be an excellent surgical procedure for older children whose acetabular development did not progress as well as was expected.     

Greater trochanteric blood flow during total hip arthroplasty using a posterior approach.

The authors investigated the effect of a posterior surgical approach on the local femoral blood supply during primary total hip arthroplasty. Greater trochanteric blood flow measurements were made with a laser Doppler flowmeter at intervals during the performance of eight uncemented and nine cemented total hip arthroplasties. Complete detachment of the quadratus femoris was associated with a significant decrease in trochanteric blood flow in the uncemented and cemented groups. The lowest perfusion levels during the procedure were seen transiently with posterior dislocation of the femoral head, after which trochanteric perfusion was decreased by 66% in the uncemented group, and 61% in the cemented group compared with baseline values. Blood flow remained approximately half of baseline values after insertion of the femoral prosthesis in the uncemented and cemented groups. These changes in greater trochanteric blood flow may serve as a marker for reduction in proximal femoral blood flow during total hip arthroplasty, and subsequently relate to the extent of bony ingrowth, periprosthetic bone loss, and ultimately the incidence of implant failure caused by aseptic loosening.     

Detection of cerebral microembolisms during extracorporeal circulation with pulsatile flow using transcranial Doppler monitoring

The incidence of focal neurological deficits and diffuse neuropsychiatric disorders in patients undergoing open-heart surgery still remains unacceptably high. The consensus is increasing that diffuse microembolism is the most important cause. Changes in blood flow velocity in the middle cerebral artery were investigated by transcranial Doppler sonography in 26 patients regarding the effect of continuous and pulsatile perfusion during extracorporeal circulation. The quotient of systolic and diastolic flow velocity was significantly increased in patients with pulsatile perfusion. Abnormal high-frequent Doppler-signals were registered in 8 patients using pulsatile perfusion without diastolic basic flow. All the other patients in whom continuous pump flow was applied (13) did not reveal any signs of hemodynamic disturbances. In the group treated with pulsatile perfusion the systolic pressures before and behind the oxygenator were significantly increased in patients with high-frequent Doppler-signals which are likely to be caused by gaseous microemboli. Investigating one type of four different oxygenators no cerebral hemodynamic alterations were recorded even during pulsatile perfusion. The use of membrane oxygenators and arterial filters during pulsatile perfusion cannot completely prevent the occurrence of gaseous microemboli; their principle causes are supposed to be the level of perfusion pressure, the flow velocity and the design of oxygenator.     

Comparative study of retrograde and selective cerebral perfusion with transcranial Doppler

BACKGROUND: Retrograde cerebral perfusion (RCP) is a simple technique and is expected to provide cerebral protection. However, its optimum management and limitations remain unclear. Transcranial Doppler has been used to monitor cerebral perfusion. Using this Doppler technique, we compared cerebral blood flow for RCP with that for selective cerebral perfusion. METHODS: Thirty-two consecutive patients underwent elective surgical repair of an aortic aneurysm involving the aortic arch at Kyushu University Hospital. Retrograde cerebral perfusion was used in 15 patients and selective cerebral perfusion, in 17 patients. Continuous measurement of middle cerebral artery blood flow velocities was performed by transcranial Doppler technique. RESULTS: Retrograde middle cerebral artery blood flow velocities during RCP could be measured in only 3 patients, whereas middle cerebral artery blood flow velocities during selective cerebral perfusion could be measured in all but 1 woman. The increase in middle cerebral artery blood flow velocities after RCP was significantly greater than that after selective cerebral perfusion. CONCLUSIONS: The measurement of middle cerebral artery blood flow velocities with transcranial Doppler technique is practicable during selective cerebral perfusion but difficult during RCP. The increase in middle cerebral artery blood flow velocities after RCP indicates reactive hyperemia and reflects the critical decrease in cerebral blood flow during this type of perfusion.     

Three Patterns of Acetabular Deficiency Are Common in Young Adult Patients With Acetabular Dysplasia

Background

Detailed recognition of the three-dimensional (3-D) deformity in acetabular dysplasia is important to help guide correction at the time of reorientation during periacetabular osteotomy (PAO). Common plain radiographic parameters of acetabular dysplasia are limited in their ability to characterize acetabular deficiency precisely. The 3-D characterization of such deficiencies with low-dose CT may allow for more precise characterization.

Questions/purposes

The purposes of this study were (1) to determine the variability in 3-D acetabular deficiency in acetabular dysplasia; (2) to define subtypes of acetabular dysplasia based on 3-D morphology; (3) to determine the correlation of plain radiographic parameters with 3-D morphology; and (4) to determine the association of acetabular dysplasia subtype with patient clinical characteristics including sex, range of motion, and femoral version.

Methods

Using our hip preservation database, we identified 153 hips (148 patients) that underwent PAO from October 2013 to July 2015. Among those, we noted 103 hips in 100 patients with acetabular dysplasia (lateral center-edge angle < 20°) and who had a Tönnis grade of 0 or 1. Eighty-six patients (86%) underwent preoperative low-dose pelvic CT scans at our institution as part of the preoperative planning for PAO. It is currently our standard to obtain preoperative low-dose pelvic CT scans (0.75–1.25 mSv, equivalent to three to five AP pelvis radiographs) on all patients before undergoing PAO unless a prior CT scan was performed at an outside institution. Hips with a history of a neuromuscular disorder, prior trauma, prior surgery, radiographic evidence of joint degeneration, ischemic necrosis, or Perthes-like deformities were excluded. Fifty hips in 50 patients met inclusion criteria and had CT scans available for review. These low-dose CT scans of 50 patients with symptomatic acetabular dysplasia undergoing evaluation for surgical planning of PAO were then retrospectively studied. CT scans were analyzed quantitatively for acetabular coverage, relative to established normative data for acetabular coverage, as well as measurement of femoral version. The cohort included 45 females and five males with a mean age of 26 years (range, 13–49 years).

Results

Lateral acetabular deficiency was present in all patients, whereas anterior deficiency and posterior deficiency were variable. Three patterns of acetabular deficiency were common: anterosuperior deficiency (15 of 50 [30%]), global deficiency (18 of 50 [36%]), and posterosuperior deficiency (17 of 50 [34%]). The presence of a crossover sign or posterior wall sign was poorly predictive of the dysplasia subtype. With the numbers available, males appeared more likely to have a posterosuperior deficiency pattern (four of five [80%]) compared with females (13 of 45 [29%], p = 0.040). Hip internal rotation in flexion was significantly greater in anterosuperior deficiency (23° versus 18°, p = 0.05), whereas external rotation in flexion was significantly greater in posterosuperior deficiency (43° versus 34°, p = 0.018). Acetabular deficiency pattern did not correlate with femoral version, which was variable across all subtypes.

Conclusions

Three patterns of acetabular deficiency commonly occur among young adult patients with mild, moderate, and severe acetabular dysplasia. These patterns include anterosuperior, global, and posterosuperior deficiency and are variably observed independent of femoral version. Recognition of these distinct morphologic subtypes is important for diagnostic and surgical treatment considerations in patients with acetabular dysplasia to optimize acetabular correction and avoid femoroacetabular impingement.