Femoral cartilage damage occurs at the zone of femoral head necrosis and can be accurately detected on traction MR arthrography of the hip in patients undergoing joint preserving hip surgery

The primary purpose was to answer the following question: What is the location and pattern of necrosis and associated chondrolabral lesions and can they be accurately detected on traction MR arthrography compared with intra-operative findings in patients undergoing hip preservation surgery for femoral head necrosis (FHN)? Retrospective, diagnostic case series on 23 patients (23 hips; mean age 29 ± 6 years) with diagnosis of FHN undergoing open/arthroscopic joint preserving surgery for FHN and pre-operative traction MR arthrography of the hip. A MR-compatible device for weight-adapted application of leg traction (15-23 kg) was used and coronal, sagittal and radial images were acquired. Location and pattern of necrosis and chondrolabral lesions was assessed by two readers and compared with intra-operative findings to calculate diagnostic accuracy of traction MR arthrography. On MRI all 23 (100%) hips showed central FHN, most frequently antero-superiorly (22/23, 96%) where a high prevalence of femoral cartilage damage was detected (18/23, 78%), with delamination being the most common (16/23, 70%) damage pattern. Intra-operative inspection showed central femoral head cartilage damage most frequently located antero-superiorly (18/23, 78%) with femoral cartilage delamination being most common (14/23, 61%). Traction MR arthrography enabled detection of femoral cartilage damage with a sensitivity/specificity of 95%/75% for reader 1 and 89%/75% for reader 2. To conclude, femoral cartilage damage occurs at the zone of necrosis and can be accurately detected using traction MR arthrography of the hip which may be helpful for surgical decision making in young patients with FHN.

Revision of a blade cut-out in PFN-A fixation: Blade exchange, cement augmentation and a cement plug as a successful salvage option

A potential and feared complication of proximal femur nails with cephalomedullary fixation is migration of the cephalomedullary screw or blade (cut-out or cut-through). In patients not suitable (e.g. low demand, comorbidities) for conversion to total hip arthroplasty blade exchange with cement augmentation may be an option. This article describes the first successful clinical use of a salvage procedure of a previously published technique, which allows the surgeon to avoid intraarticular cement leakage by using a standard cement plug to close the defect in the femoral head.

Patients with severe slipped capital femoral epiphysis treated by the modified Dunn procedure have low rates of avascular necrosis, good outcomes, and little osteoarthritis at long-term follow-up

AIMS

The modified Dunn procedure has the potential to restore the anatomy in hips with severe slipped capital femoral epiphyses (SCFE). However, there is a risk of developing avascular necrosis of the femoral head (AVN). In this paper, we report on clinical outcome, radiological outcome, AVN rate and complications, and the cumulative survivorship at long-term follow-up in patients undergoing the modified Dunn procedure for severe SCFE.

PATIENTS AND METHODS

We performed a retrospective analysis involving 46 hips in 46 patients treated with a modified Dunn procedure for severe SCFE (slip angle > 60°) between 1999 and 2016. At nine-year-follow-up, 40 hips were available for clinical and radiological examination. Mean preoperative age was 13 years, and 14 hips (30%) presented with unstable slips. Mean preoperative slip angle was 64°. Kaplan-Meier survivorship was calculated.

RESULTS

At the latest follow-up, the mean Merle d'Aubigné and Postel score was 17 points (14 to 18), mean modified Harris Hip Score was 94 points (66 to 100), and mean Hip Disability and Osteoarthritis Outcome Score was 91 points (67 to 100). Postoperative slip angle was 7° (1° to 16°). One hip (2%) had progression of osteoarthritis (OA). Two hips (5%) developed AVN of the femoral head and required further surgery. Three other hips (7%) underwent implant revision due to screw breakage or change of wires. Cumulative survivorship was 86% at ten-year follow-up.

CONCLUSION

The modified Dunn procedure for severe SCFE resulted in a low rate of AVN, low risk of progression to OA, and high functional scores at long-term follow-up. The slip deformities were mainly corrected but secondary impingement deformities can develop in some hips and may require further surgical treatment. Cite this article: Bone Joint J 2019;101-B:403-414.

[Bernese periacetabular osteotomy. : Indications, technique and results 30 years after the first description]

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.

The modified Dunn procedure for slipped capital femoral epiphysis: the Bernese experience

PURPOSE

Based on previous investigations on the vascular blood supply to the femoral head, a technique for anatomical reduction after slipped capital femoral epiphysis was developed. This technique is a modification of the original technique by Dunn using a retinacular soft-tissue flap. This allows the visual control of the epiphyseal vascular blood supply. We report the experience at the inventor's institution with a critical discussion of the available literature.

METHODS

Using a trochanteric osteotomy for surgical dislocation of the hip, a retinacular soft tissue flap is created containing the deep branch of the medial femoral circumflex artery, the external rotators and the capsule. The femoral epiphysis can be mobilised safely and reduced on the femoral neck after resection of the almost constantly present reactive metaphyseal callus.

RESULTS

In our institution, the rate of avascular necrosis with 2% is comparably low to Dunn's original results. It is only present in cases where no bleeding was already evident before reduction of the epiphysis. The ten-year long-term results are favorable in these cases with a good functional result and only little progression of osteoarthritis. However, other authors have reported higher rates of avascular necrosis up to 24% in their initial experience.

CONCLUSIONS

In experienced hands using the correct meticulous surgical technique, the results are favorable regarding the rates of avascular necrosis, the functional outcome and the development of radiographic osteoarthritis - even in acute and severe cases. Avascular necrosis is rare but can be observed if there is no evidence of intra-operative femoral head perfusion before and after reduction of the epiphysis.

Patients undergoing surgical hip dislocation for the treatment of acetabular fractures show favourable long-term outcome

Aims

The aims of this study were to determine the cumulative ten-year survivorship of hips treated for acetabular fractures using surgical hip dislocation and to identify factors predictive of an unfavourable outcome.

Patients and Methods

We followed up 60 consecutive patients (61 hips; mean age 36.3 years, standard deviation (sd) 15) who underwent open reduction and internal fixation for a displaced fracture of the acetabulum (24 posterior wall, 18 transverse and posterior wall, ten transverse, and nine others) with a mean follow-up of 12.4 years (sd 3).

Results

Clinical grading was assessed using the modified Merle d’Aubigné score. Radiographic osteoarthritis was graded according to Matta. Kaplan-Meier survivorship and a univariate Cox-regression analysis were carried out using the following endpoints: total hip arthroplasty, a Merle d’Aubigné score of < 15 and/or progression of osteoarthritis.

Conclusion

The ten-year cumulative survivorship was 82% (95% confidence interval 71 to 92). Predictors for the defined endpoints were femoral chondral lesions, marginal impaction, duration of surgery, and age of patient. Cite this article: Bone Joint J 2017;99-B:508–15.

Size and shape of the lunate surface in different types of pincer impingement: theoretical implications for surgical therapy

OBJECTIVE

Acetabular rim trimming is indicated in pincer hips with an oversized lunate surface but could result in a critically decreased size of the lunate surface in pincer hips with acetabular malorientation. There is a lack of detailed three-dimensional anatomy of lunate surface in pincer hips. Therefore, we questioned how does (1) size and (2) shape of the lunate surface differ among hips with different types of pincer impingement?

METHOD

We retrospectively compared size and shape of the lunate surface between acetabular retroversion (48 hips), deep acetabulum (34 hips), protrusio acetabuli (seven hips), normal acetabuli (30 hips), and hip dysplasia (45 hips). Using magnetic resonance imaging (MRI) arthrography with radial slices we measured size in percentage of the femoral head coverage and shape using the outer (inner) center-edge angles and width of lunate surface.

RESULTS

Hips with retroversion had a decreased size and deep hips had normal size of the lunate surface. Both had a normal shape of the outer acetabular rim. Protrusio hips had an increased size and a prominent outer acetabular rim. In all three types of pincer hips the acetabular fossa was increased.

CONCLUSION

Size and shape of the lunate surface differs substantially among different types of pincer impingement. In contrast to hips with protrusio acetabuli, retroverted and deep hips do not have an increased size of the lunate surface. Acetabular rim trimming in retroverted and deep hips should be performed with caution. Based on our results, acetabular reorientation would theoretically be the treatment of choice in retroverted hips.

Mid-term results in relation to age and analysis of predictive factors after fixation of acetabular fractures using the modified Stoppa approach

INTRODUCTION

Data concerning outcome after management of acetabular fractures by anterior approaches with focus on age and fractures associated with roof impaction, central dislocation and/or quadrilateral plate displacement are rare.

METHODS

Between October 2005 and April 2009 a series of 59 patients (mean age 57 years, range 13-91) with fractures involving the anterior column was treated using the modified Stoppa approach alone or for reduction of displaced iliac wing or low anterior column fractures in combination with the 1st window of the ilioinguinal approach or the modified Smith-Petersen approach, respectively. Surgical data, accuracy of reduction, clinical and radiographic outcome at mid-term and the need for endoprosthetic replacement in the postoperative course (defined as failure) were assessed; uni- and multivariate regression analysis were performed to identify independent predictive factors (e.g. age, nonanatomical reduction, acetabular roof impaction, central dislocation, quadrilateral plate displacement) for a failure. Outcome was assessed for all patients in general and in accordance to age in particular; patients were subdivided into two groups according to their age (group "<60yrs", group "≥60yrs").

RESULTS

Forty-three of 59 patients (mean age 54yrs, 13-89) were available for evaluation. Of these, anatomic reduction was achieved in 72% of cases. Nonanatomical reduction was identified as being the only multivariate predictor for subsequent total hip replacement (Adjusted Hazard Ratio 23.5; p<0.01). A statistically significant higher rate of nonanatomical reduction was observed in the presence of acetabular roof impaction (p=0.01). In 16% of all patients, total hip replacement was performed and in 69% of patients with preserved hips the clinical results were excellent or good at a mean follow up of 35±10 months (range: 24-55). No statistical significant differences were observed between both groups.

CONCLUSION

Nonanatomical reconstruction of the articular surfaces is at risk for failure of joint-preserving management of acetabular fractures through an isolated or combined modified Stoppa approach resulting in total joint replacement at mid-term. In the elderly, joint-preserving surgery is worth considering as promising clinical and radiographic results might be obtained at mid-term.

[Operative treatment of congenital hip osteoarthritis with high hip luxation (Crowe type IV)]

OBJECTIVE

The aim of the therapy is mechanical and functional stabilization of high dislocated hips with dysplasia coxarthrosis using total hip arthroplasty (THA).

INDICATIONS

Developmental dysplasia of the hip (DDH) in adults, symptomatic dysplasia coxarthrosis, high hip dislocation according to Crowe type III/IV, and symptomatic leg length inequality.

CONTRAINDICATIONS

Cerebrospinal dysfunction, muscular dystrophy, apparent disturbance of bone metabolism, acute or chronic infections, and immunocompromised patients.

SURGICAL TECHNIQUE

With the patient in a lateral decubitus position an incision is made between the anterior border of the gluteus maximus muscle and the posterior border of the gluteus medius muscle (Gibson interval). Identification of the sciatic nerve to protect the nerve from traction disorders by visual control. After performing trochanter flip osteotomy, preparation of the true actetabulum if possible. Implantation of the reinforcement ring, preparation of the femur and if necessary for mobilization, resection until the trochanter minor. Test repositioning under control of the sciatic nerve. Finally, refixation of the trochanteric crest.

POSTOPERATIVE MANAGEMENT

During hospital stay, intensive mobilization of the hip joint using a continuous passive motion machine with maximum flexion of 70°. No active abduction and passive adduction over the body midline. Maximum weight bearing 10-15 kg for 8 weeks, subsequently, first clinical and radiographic follow-up and deep venous thrombosis prophylaxis until full weight bearing.

RESULTS

From 1995 to 2012, 28 THAs of a Crow type IV high hip-dislocation were performed in our institute. Until now 14 patients have been analyzed during a follow-up of 8 years in 2012. Mid-term results showed an improvement of the postoperative clinical score (Merle d'Aubigné score) in 86 % of patients. Good to excellent results were obtained in 79 % of cases. Long-term results are not yet available. In one case an iatrogenic neuropraxia of the sciatic nerve was observed and after trauma a redislocation of the arthroplasty appeared in another case. In 2 cases an infection of the THA appeared 8 and 15 months after index surgery. No pseudoarthrosis of the trochanter or aseptic loosening was noticed.

High failure rate of trochanteric fracture osteosynthesis with proximal femoral locking compression plate

INTRODUCTION

Stable reconstruction of proximal femoral (PF) fractures is especially challenging due to the peculiarity of the injury patterns and the high load-bearing requirement. Since its introduction in 2007, the PF-locking compression plate (LCP) 4.5/5.0 has improved osteosynthesis for intertrochanteric and subtrochanteric fractures of the femur. This study reports our early results with this implant.

METHODS

Between January 2008 and June 2010, 19 of 52 patients (12 males, 7 females; mean age 59 years, range 19-96 years) presenting with fractures of the trochanteric region were treated at the authors' level 1 trauma centre with open reduction and internal fixation using PF-LCP. Postoperatively, partial weight bearing was allowed for all 19 patients. Follow-up included a thorough clinical and radiological evaluation at 1.5, 3, 6, 12, 24, 36 and 48 months. Failure analysis was based on conventional radiological and clinical assessment regarding the type of fracture, postoperative repositioning, secondary fracture dislocation in relation to the fracture constellation and postoperative clinical function (Merle d'Aubigné score).

RESULTS

In 18 patients surgery achieved adequate reduction and stable fixation without intra-operative complications. In one patient an ad latus displacement was observed on postoperative X-rays. At the third month follow-up four patients presented with secondary varus collapse and at the sixth month follow-up two patients had 'cut-outs' of the proximal fragment, with one patient having implant failure due to a broken proximal screw. Revision surgeries were performed in eight patients, one patient receiving a change of one screw, three patients undergoing reosteosynthesis with implantation of a condylar plate and one patient undergoing hardware removal with secondary implantation of a total hip prosthesis. Eight patients suffered from persistent trochanteric pain and three patients underwent hardware removal.

CONCLUSIONS

Early results for PF-LCP osteosynthesis show major complications in 7 of 19 patients requiring reosteosynthesis or prosthesis implantation due to secondary loss of reduction or hardware removal. Further studies are required to evaluate the limitations of this device.

Evaluation of articular cartilage in patients with femoroacetabular impingement (FAI) using T2* mapping at different time points at 3.0 Tesla MRI: a feasibility study

OBJECTIVES

To define the feasibility of utilizing T2* mapping for assessment of early cartilage degeneration prior to surgery in patients with symptomatic femoroacetabular impingement (FAI), we compared cartilage of the hip joint in patients with FAI and healthy volunteers using T2* mapping at 3.0 Tesla over time.

MATERIALS AND METHODS

Twenty-two patients (13 females and 9 males; mean age 28.1 years) with clinical signs of FAI and Tönnis grade ≤ 1 on anterior-posterior x-ray and 35 healthy age-matched volunteers were examined at a 3 T MRI using a flexible body coil. T2* maps were calculated from sagittal- and coronal-oriented gradient-multi-echo sequences using six echoes (TR 125, TE 4.41/8.49/12.57/16.65/20.73/24.81, scan time 4.02 min), both measured at beginning and end of the scan (45 min time span between measurements). Region of interest analysis was manually performed on four consecutive slices for superior and anterior cartilage. Mean T2* values were compared among patients and volunteers, as well as over time using analysis of variance and Student's t-test.

RESULTS

Whereas quantitative T2* values for the first measurement did not reveal significant differences between patients and volunteers, either for sagittal (p = 0.644) or coronal images (p = 0.987), at the first measurement, a highly significant difference (p ≤ 0.004) was found for both measurements with time after unloading of the joint. Over time we found decreasing mean T2* values for patients, in contrast to increasing mean T2* relaxation times in volunteers.

CONCLUSION

The study proved the feasibility of utilizing T2* mapping for assessment of early cartilage degeneration in the hip joint in FAI patients at 3 Tesla to predict possible success of joint-preserving surgery. However, we suggest the time point for measuring T2* as an MR biomarker for cartilage and the changes in T2* over time to be of crucial importance for designing an MR protocol in patients with FAI.

The Pararectus approach for anterior intrapelvic management of acetabular fractures

A new anterior intrapelvic approach for the surgical management of displaced acetabular fractures involving predominantly the anterior column and the quadrilateral plate is described. In order to establish five ‘windows’ for instrumentation, the extraperitoneal space is entered along the lateral border of the rectus abdominis muscle. This is the so-called ‘Pararectus’ approach. The feasibility of safe dissection and optimal instrumentation of the pelvis was assessed in five cadavers (ten hemipelves) before implementation in a series of 20 patients with a mean age of 59 years (17 to 90), of whom 17 were male. The clinical evaluation was undertaken between December 2009 and December 2010. The quality of reduction was assessed with post-operative CT scans and the occurrence of intra-operative complications was noted. In cadavers, sufficient extraperitoneal access and safe instrumentation of the pelvis were accomplished. In the patients, there was a statistically significant improvement in the reduction of the fracture (pre- versus post-operative: mean step-off 3.3 mm (sd 2.6) vs 0.1 mm (sd 0.3), p < 0.001; and mean gap 11.5 mm (sd 6.5) vs 0.8 mm (sd 1.3), p < 0.001). Lesions to the peritoneum were noted in two patients and minor vascular damage was noted in a further two patients. Multi-directional screw placement and various plate configurations were feasible in cadavers without significant retraction of soft tissues.

In the treatment of acetabular fractures predominantly involving the anterior column and the quadrilateral plate, the Pararectus approach allowed anatomical restoration with minimal morbidity related to the surgical access.

The cam-type deformity of the proximal femur arises in childhood in response to vigorous sporting activity

BACKGROUND

The prevalence of a cam-type deformity in athletes and its association with vigorous sports activities during and after the growth period is unknown.

QUESTIONS/PURPOSES

We therefore compared the prevalence and occurrence of a cam-type deformity by MRI in athletes during childhood and adolescence with an age-matched control group.

PATIENTS AND METHODS

We retrospectively reviewed 72 hips in 37 male basketball players with a mean age of 17.6 years (range, 9-25 years) and 76 asymptomatic hips of 38 age-matched volunteers who had not participated in sporting activities at a high level.

RESULTS

Eleven (15%) of the 72 hips in the athletes were painful and had positive anterior impingement tests on physical examination. Internal rotation of the hip averaged 30.1° (range, 15°-45°) in the control group compared with only 18.9° (range, 0°-45°) in the athletes. The maximum value of the alpha angle throughout the anterosuperior head segment was larger in the athletes (average, 60.5° ± 9°), compared with the control group (47.4° ± 4°). These differences became more pronounced after closure of the capital growth plate. Overall, the athletes had a 10-fold increased likelihood of having an alpha angle greater than 55° at least at one measurement position.

CONCLUSIONS

Our observations suggest a high intensity of sports activity during adolescence is associated with a substantial increase in the risk of cam-type impingement. These patients also may be at increased risk of subsequent development of secondary coxarthrosis.

LEVEL OF EVIDENCE

Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Long-term outcome after traumatic anterior dislocation of the hip

INTRODUCTION

Traumatic anterior dislocation of the hip joint is rare. Additional injuries to the hip due to dislocation are even more infrequent. Outcome is limited by osteoarthritic joint degeneration or the occurrence of avascular necrosis of the femoral head.

METHOD

Anterior hip dislocation occurred in ten of 100 patients with traumatic hip dislocations (8 men, mean age: 43, 22-62years) at two major trauma centres, between January 2001 and December 2008. Four patients had impaction fractures of the femoral head and three patients had fractures of the anterior acetabular wall. One patient presented with an open dislocation. In three of the ten patients surgical treatment was necessary.

RESULTS

Nine patients were evaluated retrospectively at a follow-up of 4.8 ± 2.3 years (mean ± SD). The mean scores were 88 ± 19 (Harris Hip-Score), 15 ± 23 (WOMAC-Score), level 6 (UCLA-Score). Four cases presented with only fair clinical or radiological results according to Epstein. AVN with collapse of the femoral head was observed in one.

CONCLUSION

Traumatic anterior hip dislocations presented in six of the ten cases with additional injuries to the hip. Surgical treatment in cases with deep impaction fractures of the femoral head or with large fragments of the acetabulum may improve the outcome.

The iliocapsularis muscle: an important stabilizer in the dysplastic hip

BACKGROUND

The iliocapsularis muscle is a little known muscle overlying the anterior hip capsule postulated to function as a stabilizer of dysplastic hips. Theoretically, this muscle would be hypertrophied in dysplastic hips and, conversely, atrophied in stable and well-constrained hips. However, these observations have not been confirmed and the true function of this muscle remains unknown.

QUESTIONS/PURPOSES

We quantified the anatomic dimensions and degree of fatty infiltration of the iliocapsularis muscle and compared the results for 45 hips with deficient acetabular coverage (Group I) with 40 hips with excessive acetabular coverage (Group II).

PATIENTS AND METHODS

We used MR arthrography to evaluate anatomic dimensions (thickness, width, circumference, cross-sectional area [CSA], and partial volume) and the amount of fatty infiltration.

RESULTS

We observed increased thickness, width, circumference, CSA, and partial volume of the iliocapsularis muscle in Group I when compared with Group II. Additionally, hips in Group I had a lower prevalence of fatty infiltration compared with those in Group II. The iliocapsularis muscle typically was hypertrophied, and there was less fatty infiltration in dysplastic hips compared with hips with excessive acetabular coverage.

CONCLUSION

These observations suggest the iliocapsularis muscle is important for stabilizing the femoral head in a deficient acetabulum. This muscle serves as an anatomic landmark when performing a periacetabular osteotomy. Additionally, preoperative evaluation of morphologic features of the muscle can be used as an adjunct for decision making when treating patients with borderline hip dysplasia or femoroacetabular impingement.

Synovial sarcomas usually metastasize after >5 years: a multicenter retrospective analysis with minimum follow-up of 10 years for survivors

BACKGROUND

Synovial sarcoma (SS) is a malignant soft tissue sarcoma with a poor prognosis because of late local recurrence and distant metastases. To our knowledge, no studies have minimum follow-up of 10 years that evaluate long-term outcomes for survivors.

PATIENTS AND METHODS

Data on 62 patients who had been treated for SS from 1968 to 1999 were studied retrospectively in a multicenter study. Mean follow-up of living patients was 17.2 years and of dead patients 7.7 years.

RESULTS

Mean age at diagnosis was 35.4 years (range 6-82 years). Overall survival was 38.7%. The 5-year survival was 74.2%; 10-year survival was 61.2%; and 15-year survival was 46.5%. Fifteen patients (24%) died of disease after 10 years of follow-up. Local recurrence occurred after a mean of 3.6 years (range 0.5-14.9 years) and metastases at a mean of 5.7 years (range 0.5-16.3 years). Only four patients were treated technically correctly with a planned biopsy followed by a wide resection or amputation. Factors associated with significantly worse prognosis included larger tumor size, metastases at the time of diagnosis, high-grade histology, trunk-related disease, and lack of wide resection as primary surgical treatment.

CONCLUSIONS

In SS, metastases develop late with high mortality. Patients with SS should be followed for >10 years.

Surgical dislocation of the hip for the fixation of acetabular fractures

Surgical dislocation of the hip in the treatment of acetabular fractures allows the femoral head to be safely displaced from the acetabulum. This permits full intra-articular acetabular and femoral inspection for the evaluation and potential treatment of cartilage lesions of the labrum and femoral head, reduction of the fracture under direct vision and avoidance of intra-articular penetration with hardware. We report 60 patients with selected types of acetabular fracture who were treated using this approach. Six were lost to follow-up and the remaining 54 were available for clinical and radiological review at a mean follow-up of 4.4 years (2 to 9).

Substantial damage to the intra-articular cartilage was found in the anteromedial portion of the femoral head and the posterosuperior aspect of the acetabulum. Labral lesions were predominantly seen in the posterior acetabular area. Anatomical reduction was achieved in 50 hips (93%) which was considerably higher than that seen in previous reports. There were no cases of avascular necrosis. Four patients subsequently required total hip replacement. Good or excellent results were achieved in 44 hips (81.5%). The cumulative eight-year survivorship was 89.0% (95% confidence interval 84.5 to 94.1). Significant predictors of poor outcome were involvement of the acetabular dome and lesions of the femoral cartilage greater than grade 2. The functional mid-term results were better than those of previous reports.

Surgical dislocation of the hip allows accurate reduction and a predictable mid-term outcome in the management of these difficult injuries without the risk of the development of avascular necrosis.

Surgical dislocation of the hip for a locked traumatic posterior dislocation with associated femoral neck and acetabular fractures

Traumatic posterior dislocation of the hip associated with a fracture of the posterior acetabular wall and of the neck of the femur is a rare injury. A 29-year-old man presented at a level 1 trauma centre with a locked posterior dislocation of the right hip, with fractures of the femoral neck and the posterior wall of the acetabulum after a bicycle accident. An attempted closed reduction had failed. This case report describes in detail the surgical management and the clinical and radiological outcome. Open reduction and fixation with preservation of the intact retinaculum was undertaken within five hours of injury with surgical dislocation of the hip and a trochanteric osteotomy. Two years after operation the function of the injured hip was good. Plain radiographs and MR scans showed early signs of osteoarthritis with some loss of joint space but no evidence of avascular necrosis. The patient had begun skiing and hiking again. The combination of fractures of the neck of the femur and of the posterior wall of the acetabulum hampers closed reduction of a posterior dislocation of the hip. Surgical dislocation of the hip with trochanteric flip osteotomy allows controlled open reduction of the fractures, with inspection of the hip joint and preservation of the vascular supply.

Cartilage damage in femoroacetabular impingement (FAI): preliminary results on comparison of standard diagnostic vs delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC)

OBJECTIVES

To study the three-dimensional (3D) T1 patterns in different types of femoroacetabular impingement (FAI) by utilizing delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) and subsequent 3D T1 mapping. We used standard grading of OA by Tonnis grade on standard radiographs and morphological grading of cartilage in MRI for comparative analysis.

METHODS

dGEMRIC was obtained from ten asymptomatic young-adult volunteers and 26 symptomatic FAI patients. MRI included the routine hip protocol and a dual-flip angle (FA) 3D gradient echo (GRE) sequence utilizing inline T1 measurement. Cartilage was morphologically classified from the radial images based on the extent of degeneration as: no degeneration, degeneration zone measuring <0.75 cm from the rim, >0.75 cm, or total loss. T1 findings were evaluated and correlated.

RESULTS

All FAI types revealed remarkably lower T1 mean values in comparison to asymptomatic volunteers in all regions of interest. Distribution of the T1 dGEMRIC values was in accordance with the specific FAI damage pattern. In cam-types (n=6) there was a significant drop (P<0.05) of T1 in the anterior to superior location. In pincer-types (n=7), there was a generalized circumferential decrease noted. High inter-observer (intra-observer) reliability was noted for T1 assessment using intra-class correlation (ICC):intra-class coefficient=0.89 (0.95).

CONCLUSIONS

We conclude that a pattern of zonal T1 variation does seem to exist that is unique for different sub-groups of FAI. The FA GRE approach to perform 3D T1 mapping has a promising role for further studies of standard MRI and dGEMRIC in the hip joint.

[Radiological diagnosis of femoroacetabular impingement]

Femoroacetabular impingements (FAI) are due to an anatomical disproportion between the proximal femur and the acetabulum which causes premature wear of the joint surfaces. An operation is often necessary in order to relieve symptoms such as limited movement and pain as well as to prevent or slow down the degenerative process. The result is dependent on the preoperative status of the joint with poor results for advanced arthritis of the hip joint. This explains the necessity for an accurate diagnosis in order to recognize early stages of damage to the joint. The diagnosis of FAI includes clinical examination, X-ray examination and magnetic resonance imaging (MRI). The standard X-radiological examination for FAI is carried out using two X-ray images, an anterior-posterior view of the pelvis and a lateral view of the proximal femur, such as the cross-table lateral or Lauenstein projections. It is necessary that positioning criteria are adhered to in order to avoid distortion artifacts. MRI permits an examination of the pelvis on three levels and should also include radial planned sequences for improved representation of peripheral structures, such as the labrum and peripheral cartilage. The use of contrast medium for a direct MR arthrogram has proved to be advantageous particularly for representation of labrum damage. The data with respect to cartilage imaging are still unclear. Further developments in technology, such as biochemical-sensitive MRI applications, will be able to improve the diagnosis of the pelvis in the near future.

[Femoroacetabular impingement: radiographic diagnosis--what the radiologist should know]

OBJECTIVE

The purpose of this article is to show the important radiographic criteria that indicate the two types of femoroacetabular impingement: pincer and cam impingement. In addition, potential pitfalls in pelvic imaging concerning femoroacetabular impingement are shown.

CONCLUSION

Femoroacetabular impingement is a major cause for early "primary" osteoarthritis of the hip. It can easily be recognized on conventional radiographs of the pelvis and the proximal femur.

[Imaging in developmental dysplasia of the hip]

Modern imaging techniques are an invaluable tool for assessing pathomorphological changes of the hip. Thorough diagnostic analysis and therapeutic decision making mainly rely on correct interpretation of conventional radiographic projections as well as more modern techniques, including magnetic resonance arthrography. This article gives an overview of the imaging techniques that are routinely used for assessing pathological conditions of the hip, with a special focus on diagnostic findings in developmental dysplasia of the hip as well as in femoroacetabular impingement.

[The value of diskography in disk-related pain syndrome of the cervical spine for evaluation of indications for spondylodesis]

In this study the postoperative results of patients with cervical spondylodesis for "discogenic pain syndrome" were evaluated. The diagnosis "discogenic pain syndrome" as well as the pathologic segments were confirmed by cervical discography. However interpretation of the discogram as "positive" was only considered reliable when typical pain provocation through discography correlated with pathologic disc pattern ("functional test"). 38 cervical segments have been found to fulfill these criteria and were fused in 29 operative procedures (21 unisegmental, 7 bisegmental, one trisegmental). The patients were evaluated postoperative for change of symptoms, pain character and intensity, neurological deficits, working and sporting disability and mobility of cervical spine. According to the criteria of Simmons and Segil 73% of the patients showed a good to excellent result. A fair result was found in 23.2% and an unsatisfactory result was seen in 3.8%. In the literature a good to excellent outcome is seen in 30 to 46% in similar patients groups after cervical fusion without preoperative assessment by discography.

Femoral morphology differs between deficient and excessive acetabular coverage

Structural deformities of the femoral head occurring during skeletal development (eg, Legg-Calvé-Perthes disease) are associated with individual shapes of the acetabulum but it is unclear whether differences in acetabular shape are associated with differences in proximal femoral shape. We questioned whether the amount of acetabular coverage influences femoral morphology. We retrospectively compared the proximal femoral anatomy of 50 selected patients (50 hips) with developmental dysplasia of the hip (lateral center-edge angle [LCE] < or = 25 degrees ; acetabular index > or = 14 degrees ) with 45 selected patients (50 hips) with a deep acetabulum (LCE > or = 39 degrees ). Using MRI arthrography we measured head sphericity, epiphyseal shape, epiphyseal extension, and femoral head-neck offset. A deep acetabulum was associated with a more spherical head shape, increased epiphyseal height with a pronounced extension of the epiphysis towards the femoral neck, and an increased offset. In contrast, dysplastic hips showed an elliptical femoral head, decreased epiphyseal height with a less pronounced extension of the epiphysis, and decreased head-neck offset. Hips with different acetabular coverage are associated with different proximal femoral anatomy. A nonspherical head in dysplastic hips could lead to joint incongruity after an acetabular reorientation procedure.

LEVEL OF EVIDENCE

Level IV, retrospective comparative study. See the Guidelines for Authors for a complete description of levels of evidence.

Hip2Norm: an object-oriented cross-platform program for 3D analysis of hip joint morphology using 2D pelvic radiographs

We developed an object-oriented cross-platform program to perform three-dimensional (3D) analysis of hip joint morphology using two-dimensional (2D) anteroposterior (AP) pelvic radiographs. Landmarks extracted from 2D AP pelvic radiographs and optionally an additional lateral pelvic X-ray were combined with a cone beam projection model to reconstruct 3D hip joints. Since individual pelvic orientation can vary considerably, a method for standardizing pelvic orientation was implemented to determine the absolute tilt/rotation. The evaluation of anatomically morphologic differences was achieved by reconstructing the projected acetabular rim and the measured hip parameters as if obtained in a standardized neutral orientation. The program had been successfully used to interactively objectify acetabular version in hips with femoro-acetabular impingement or developmental dysplasia. Hip(2)Norm is written in object-oriented programming language C++ using cross-platform software Qt (TrollTech, Oslo, Norway) for graphical user interface (GUI) and is transportable to any platform.

Severe spinal injuries in alpine skiing and snowboarding: a 6-year review of a tertiary trauma centre for the Bernese Alps ski resorts, Switzerland

OBJECTIVE

To analyse the epidemiological data, injury pattern, clinical features and mechanisms of severe spinal injuries related to alpine skiing and snowboarding.

STUDY DESIGN

A six-year review of all adult patients with severe spinal injuries sustained from alpine skiing or snowboarding.

SETTING

Tertiary trauma centre in Bern, Switzerland.

PATIENTS AND METHODS

All adult patients (over 16 years of age) admitted to a tertiary trauma centre from 1 July 2000, through 30 June 2006, were reviewed using a computerised database. From these records, a total of 728 patients injured from snow sports were identified. Severe spinal injuries (defined as spinal fractures, subluxations, dislocations or concomitant spinal cord injuries) were found in 73 patients (17 female, 56 male). The clinical features of these patients were reviewed with respect to epidemiological factors, mechanism of injury, fracture pattern, and neurological status.

RESULTS

The majority of severe spinal injuries (n = 63) were related to skiing. Fatal central-nervous injuries and transient or persistent neurological symptoms occurred in 28 patients (23 skiers, 5 snowboarders). None of the snowboarders suffered from persistent neurological sequelae. Snowboarders with severe spinal injuries (n = 10) were all male (p<0.05), and were significantly younger than skiers (p<0.001). The most commonly affected site was the lumbar spine. However, 39 patients (53.4%) suffered from injury pattern at two or more levels.

CONCLUSIONS

With advances in technology and slope maintenance, skiers and snowboarders progress to higher skill levels and faster speeds more rapidly than ever before. Great efforts have been focused on reducing extremity injuries in snow sports, but until recently very little attention has been given to spinal injury prevention on the slopes. Suggestions for injury prevention include the use of spine protectors, participation on appropriate runs for ability level, proper fit and adjustment of equipment, and taking lessons with the goal of increasing ability and learning hill etiquette.

Irritation der Iliopsoassehne nach totalendoprothetischem Hüftgelenkersatz

Chronic irritation of the iliopsoas tendon is a rare cause of persistent pain after total joint replacement of the hip. In the majority of cases, pain results from a mechanical conflict between the iliopsoas tendon and the anterior edge of the acetabular cup after total hip arthroplasty. Pain can be reproduced by active flexion of the hip and by active raising of the straightened leg. In addition, painful leg raising against resistance and passive hyperextension are suggestive of an irritation of the iliopsoas tendon. Symptoms evolve from a mechanical irritation of the iliopsoas tendon and an oversized or retroverted acetabular cup, screws penetrating into the inner aspect of the ilium, or from bone cement protruding beyond the anterior acetabular rim. The diagnosis may be assumed on conventional radiographs and confirmed by CT scans. Fifteen patients with psoas irritation after total hip replacement are reported on. Eleven patients were treated surgically. The acetabular cup was revised and reoriented with more anteversion in six patients, isolated screws penetrating into the tendon were cut and leveled in three patients, and prominent bone cement in conflict with the tendon was resected once. A partial release of the iliopsoas tendon only was performed in another patient. Follow-up examination (range: 11-89 months) revealed that nine patients were free of pain and two patient had mild residual complaints. Psoas irritation in combination with total hip replacement can be prevented by a correct surgical technique, especially with proper selection of the cup size and insertion of the acetabular cup avoiding a rim position exceeding the level of the anterior acetabular rim.

Range of motion in anterior femoroacetabular impingement

The range of motion of normal hips and hips with femoroacetabular impingement relative to some specific anatomic reference landmarks is unknown. We therefore described: (1) the range of motion pattern relative to landmarks; (2) the location of the impingement zones in normal and impinging hips; and (3) the influence of surgical débridement on the range of motion. We used a previously developed and validated noninvasive 3-D CT-based method for kinematic hip analysis to compare the range of motion pattern, the location of impingement, and the effect of virtual surgical reconstruction in 28 hips with anterior femoroacetabular impingement and a control group of 33 normal hips. Hips with femoroacetabular impingement had decreased flexion, internal rotation, and abduction. Internal rotation decreased with increasing flexion and adduction. The calculated impingement zones were localized in the anterosuperior quadrant of the acetabulum and were similar in the two groups and in impingement subgroups. The average improvement of internal rotation was 5.4 degrees for pincer hips, 8.5 degrees for cam hips, and 15.7 degrees for mixed impingement. This method helps the surgeon quantify the severity of impingement and choose the appropriate treatment option; it provides a basis for future image-guided surgical reconstruction in femoroacetabular impingement with less invasive techniques.

Estimation of pelvic tilt on anteroposterior X-rays--a comparison of six parameters

OBJECTIVE

To compare six different parameters described in literature for estimation of pelvic tilt on an anteroposterior pelvic radiograph and to create a simple nomogram for tilt correction of prosthetic cup version in total hip arthroplasty.

DESIGN

Simultaneous anteroposterior and lateral pelvic radiographs are taken routinely in our institution and were analyzed prospectively. The different parameters (including three distances and three ratios) were measured and compared to the actual pelvic tilt on the lateral radiograph using simple linear regression analysis.

PATIENTS

One hundred and four consecutive patients (41 men, 63 women with a mean age of 31.7 years, SD 9.2 years, range 15.7-59.1 years) were studied.

RESULTS

The strongest correlation between pelvic tilt and one of the six parameters for both men and women was the distance between the upper border of the symphysis and the sacrococcygeal joint. The correlation coefficient was 0.68 for men (P<0.001) and 0.61 for women (P<0.001). Based on this linear correlation, a nomogram was created that enables fast, tilt-corrected cup version measurements in clinical routine use.

CONCLUSION

This simple method for correcting variations in pelvic tilt on plain radiographs can potentially improve the radiologist's ability to diagnose and interpret malformations of the acetabulum (particularly acetabular retroversion and excessive acetabular overcoverage) and post-operative orientation of the prosthetic acetabulum.

Trochanteric flip osteotomy for cranial extension and muscle protection in acetabular fracture fixation using a Kocher-Langenbeck approach

OBJECTIVE

To describe the advantages and surgical technique of a trochanteric flip osteotomy in combination with a Kocher-Langenbeck approach for the treatment of selected acetabular fractures.

DESIGN

Consecutive series, teaching hospital.

METHODS

Through mobilization of the vastus lateralis muscle, a slice of the greater trochanter with the attached gluteus medius muscle can be flipped anteriorly. The gluteus minimus muscle can then be easily mobilized, giving free access to the posterosuperior and superior acetabular wall area. Damage to the abductor muscles by vigorous retraction can be avoided, potentially resulting in less ectopic ossification. Ten consecutive cases of acetabular fractures treated with this approach are reported. In eight cases, an anatomic reduction was achieved; in the remaining two cases with severe comminution, the reduction was within one to three millimeters. The trochanteric fragment was fixed with two 3.5-millimeter cortical screws.

RESULTS

All osteotomies healed in anatomic position within six to eight weeks postoperatively. Abductor strength was symmetric in eight patients and mildly reduced in two patients. Heterotopic ossification was limited to Brooker classes 1 and 2 without functional impairment at an average follow-up of twenty months. No femoral head necrosis was observed.

CONCLUSION

This technique allows better visualization, more accurate reduction, and easier fixation of cranial acetabular fragments. Cranial migration of the greater trochanter after fixation with two screws is unlikely to occur because of the distal pull of the vastus lateralis muscle, balancing the cranial pull of the gluteus medius muscle.

Tilt and rotation correction of acetabular version on pelvic radiographs

Anteroposterior pelvic radiographs are the gold standard of imaging for mechanical hip problems. However, correct interpretation is difficult because the projected morphologic features of the acetabulum and nearly all routinely used hip parameters depend on individual pelvic position, which can vary considerably during acquisition. We developed software that recreates the projected acetabular rim and the measured hip parameters as if obtained in a standardized orientation. The vertical and horizontal distances between two easy identifiable points were used as indicators of tilt and rotation. These points were the middle of the sacrococcygeal joint and the middle of the upper border of the symphyseal gap. Calibration of the indicators was achieved by means of serial pelvic radiographs of 20 cadaver pelves. Validation of tilt indicator in 100 patients and a theoretical error analysis revealed that for accurate tilt prediction an additional one-time lateral radiograph of the pelvis is mandatory. The computer-assisted method allows standardized evaluation of anatomic morphologic differences of femoral coverage (dysplasia, retroversion), making their clinical relevance for development of early osteoarthritis more valuable.

A new methodology for the planning of single-cut corrective osteotomies of mal-aligned long bones

BACKGROUND

Corrections of combined torsional and angular deformities of long bones may be performed creating a single osteotomy which is oriented so that rotating the two fragments on the created osteotomy plane allows to correct all deformities in one step. A practical geometrical tool is presented to facilitate the difficult preoperative planning of such osteotomies.

METHODS

The geometrical tool consists of two limbs connected by a mobile disk representing the osteotomy plane. This allows the two limbs to be deliberately bent and rotated against each other. Thereby, the mobile disk will change orientation in such a way that it will indicate the osteotomy plane needed in order to anatomically align the two limbs. The geometrical principle of the tool has been confirmed mathematically and compared with data from the literature. Five deformed test bones have been used to test the effectiveness of the tool.

FINDING

. The geometrical principle of the tool is equivalent with the mathematical data from the literature. The maximal osteotomy angle which can be indicated by the tool is 65 degrees , with an error of +/-3 degrees compared to mathematically calculated values. The five test bones were all aligned anatomically with appropriate accuracy.

INTERPRETATION

The presented tool can be easily used and facilitates largely the preoperative planning of a single cut osteotomy for complex deformities of long bones. It allows to avoid sophisticated mathematical calculations and helps to avoid the risk for errors in planning and performing correctional osteotomies.

Incisional hernia after periacetabular osteotomy

The incidence of incisional abdominal hernias, an unreported complication after a Bernese periacetabular osteotomy, was evaluated. Two cases of an incisional hernia above the iliac crest were detected in a series of 950 cases since 1984. Although the incidence has been small, risk factors may be obesity, weak abdominal muscle strength, or increased abdominal pressure attributable to chronic coughing or obstipation. The surgeon should recognize the importance of restoring continuity of the abdominal fascia in patients with such factors.

Abnormal extension of the femoral head epiphysis as a cause of cam impingement

The etiology of an insufficient femoral head-neck offset has not been identified yet. It was investigated whether a decreased head-neck offset might be correlated with an unusual orientation of the physeal capital scar. Therefore, the femoral head-neck offset and the extension of the physeal scar onto the femoral neck were measured with specific magnetic resonance imaging arthrography. The measurements were done in 15 patients with anterior femoroacetabular impingement attributable to a nonspherical head and were compared with 15 age- and gender-matched control subjects. Eight serial magnetic resonance imaging sections perpendicular to the femoral neck axis were used in each hip to measure the head-neck offset and the epiphyseal extension toward the femoral neck at 16 measurement points. In both groups there was an inverse correlation between the amount of head-neck offset and the relative extension of the capital physeal scar in the cranial hemisphere of the head. Within the anterosuperior head quadrant, there was statistically significant different decrease of the head-neck offset and increase of the lateral epiphyseal extension in the patients compared with the control subjects. These findings suggest a growth abnormality of the capital physis as one probable underlying cause for a nonspherical head.

Early osteoarthritic changes of human femoral head cartilage subsequent to femoro-acetabular impingement

OBJECTIVE

To use the surgical samples of patients with femoro-acetabular impingement due to a nonspherical head to analyze tissue morphology and early cartilage changes in a mechanical model of hip osteoarthritis (OA).

DESIGN

An aberrant nonspherical shape of the femoral head has been assumed to cause an abutment conflict (impingement mechanism) of the hip with subsequent cartilage lesions of the acetabular rim and surface alterations of the nonspherical portion of the head. In this study, 22 samples of the nonspherical portions of the head have been obtained during hip surgery from young adults (mean 30.4 years, range 19-45 years) with an impingement conflict. The samples were first compared with tissue from the same area obtained from six age-matched deceased persons (control group) with normal hip morphology and second with cartilage from 14 older patients with advanced OA. All samples were characterized histologically and hyaline cartilage was graded according to the Mankin criteria. They were further subjected to examination on a molecular basis by immunohistology for cartilage oligomeric matrix protein (COMP), tenascin-C and a collagenase cleavage product (COL2-3/4C(long)) and by in situ hybridization for collagen type I and collagen type II.

RESULTS

All samples from the patient group revealed hyaline cartilage with degenerative signs. According to the Mankin criteria, the cartilage alterations were significantly different when compared with the control group (p=0.007) but were less distinct when compared with cartilage from patients with advanced OA (p=0.014). Positive staining and distribution pattern for COMP, tenascin-C and COL2-3/4C(long) showed similarities between the samples from the impingement group and osteoarthritic cartilage but they were distinctly different when compared with healthy cartilage. Levels of collagen I and II transcripts were upregulated in 6 and 10, respectively, of the 14 samples with OA and in 9 and 12, respectively, of the 22 samples from the impingement group. None of the samples from the control group showed upregulation of Collagen I and II mRNA.

CONCLUSIONS

The aberrant nonspherical portion of the femoral head in young patients with an impingement conflict consists of hyaline cartilage which shows clear degenerative signs similar to the findings in osteoarthritic cartilage. The tissue alterations are distinctly different when compared with a control group, which substantiates an impingement conflict as an early mechanism for degeneration at the hip joint periphery.

Effect of pelvic tilt on acetabular retroversion: a study of pelves from cadavers

Pelvic inclination is difficult to control on a standard radiograph of the pelvis and has a direct influence on the appearance of acetabular version. By defining the normal range of the distance between the symphysis and the sacrococcygeal joint on 86 standard anteroposterior radiographs of pelves a technique was developed to evaluate pelvic inclination. A statistically significant correlation between this distance and pelvic inclination was shown in four cadaver pelves. Acetabular retroversion signs (cross-over, posterior wall signs) were evaluated on normal pelves from cadavers (two females, two males) after mounting on a holding device and wire marking of the acetabular rims. Radiographs were taken 3 degrees stepwise through the range of 9 degrees inclination to 12 degrees reclination. At the neutral position, two acetabula appeared with both positive retroversion signs compared with none at 6 degrees reclination. At 9 degrees pelvic inclination all acetabula had both signs. Retroversion signs were significantly more pronounced and found at lower pelvic tilt angles in the pelves from males than from females. Evaluation of pelvic inclination will help to decrease measurement errors in assessment of acetabular orientation and femoral head coverage. This will be valuable in preoperative planning of reorientation procedures.

Anterior femoro-acetabular impingement due to acetabular retroversion. Treatment with periacetabular osteotomy

BACKGROUND

This study was performed to evaluate whether symptomatic anterior femoro-acetabular impingement due to acetabular retroversion can be treated effectively with a periacetabular osteotomy.

METHODS

The diagnosis of femoro-acetabular impingement was based on clinical symptoms, a positive anterior impingement test, and findings of acetabular rim lesions on magnetic resonance imaging. The radiographic diagnosis of acetabular retroversion was based on the cross-over and posterior wall signs. Twenty-nine hips in twenty-two patients (average age, twenty-three years) underwent a periacetabular osteotomy. An arthrotomy was performed in twenty-six hips in order to visualize intra-articular lesions and, in selected cases, to improve a low femoral head-neck offset. The range of motion of the hip was measured, clinical evaluation was performed with use of the score described by Merle d'Aubigné and Postel, and the anterior center-edge angle of Lequesne and de Sèze was measured on radiographs preoperatively and at the time of the latest follow-up.

RESULTS

The duration of follow-up averaged thirty months (range, twenty-four to forty-nine months). The anterior center-edge angle of Lequesne and de Sèze decreased significantly from a preoperative average of 36 degrees (range, 26 degrees to 52 degrees ) to a postoperative average of 28 degrees (range, 16 degrees to 46 degrees ) (p = 0.002). There was a significant increase in the average range of internal rotation (10 degrees, p = 0.006), flexion (7 degrees, p = 0.014), and adduction (8 degrees, p = 0.017). The average Merle d'Aubigné score increased from 14.0 points (range, 12 to 16 points) preoperatively to 16.9 points (range, 15 to 18 points) postoperatively (p < 0.001), and the result was good or excellent for twenty-six hips. Three hips underwent subsequent surgery: one, because of early postoperative loss of reduction; one, for correction of posteroinferior impingement; and one, because of recurrent signs of anterior impingement.

CONCLUSION

Periacetabular osteotomy is an effective way to reorient the acetabulum in young adults with symptomatic anterior femoro-acetabular impingement due to acetabular retroversion

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.

Perfusion of the femoral head during surgical dislocation of the hip

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.

Osteolytic lesion in the greater trochanter mimicking tumor

Two patients with an osteolytic lesion of the greater trochanter suggesting a malignant bone tumor are presented. Biopsy, microbiological and histological examination suggested a diagnosis of trochanteric tuberculosis. Treatment consisted of multiple surgical debridements and antituberculous chemotherapy. The incidence of similar cases is expected to increase with the rising incidence of tuberculosis.

[Hooked roof cup in revision of difficult loose hip prosthesis cups. Results after a minimum of 10 years]

The long-term results of acetabular revision after total hip arthroplasty (THA) with the use of a reinforcement ring with hook were evaluated. The study included 57 cases of surgery dating back 10 years or more. Of a total of 54 patients (57 operated hips), 18 patients (19 hips) died during the 10-year period and 2 patients (2 hips) were completely lost to follow-up. At the time of the revision surgery, the mean age of the remaining 34 patients (36 hips) was 62.5 years (range: 47-80). A THA revision was done in 25 cases and an acetabular revision only in 11 cases. The most common acetabular defect was a combined segmental and cavitary defect (n = 19), and in three cases there was pelvic discontinuity. Autologous or homologous cancellous bone grafts were used to fill acetabular cavities in 17 hip joints. Structured bone grafts, predominantly homologous bone, were used in ten cases for acetabular reconstruction. At a mean follow-up of 11.4 years (range: 10-14.5) three hip joints (8%) had undergone further revision. The revisions were done for aseptic loosening of the acetabular component in two cases and a septic loosening of both components in one case. Three further cases (8%) revealed signs of acetabular loosening. Two of these three patients were symptomatic but refused further revision surgery. In the 33 unrevised hip joints, a good or excellent clinical result with a d'Aubingé score of more than 14 points was found in 30 cases (92%). Osseous acetabular reconstruction with the use of a reinforcement ring leads to favorable results compared to other techniques. In the authors' opinion, this technique is preferable to those using oversized cups without osseous reconstruction of the acetabulum.

Rationale of periacetabular osteotomy and background work

The Bernese periacetabular osteotomy is a joint-preserving procedure used after growth plate closure to correct acetabular coverage and stabilize the femoral head. The polygonal, juxta-articular osteotomy respects the vascular blood supply to the acetabular fragment and facilitates an extensive acetabular reorientation. It achieves improvement of the insufficient coverage of the femoral head, reduction of mediolateral displacement, and correction of the version of the fragment. All osteotomies are performed through the modified Smith-Petersen approach, which also allows for an anterior capsulotomy. Joint inspection not only provides information on lesions of the rim but also facilitates the control of an impingement-free range of motion after the correction. The posterior column remains partially intact, allowing minimal internal fixation of the acetabular fragment and early mobilization similar to that after an intertrochanteric osteotomy. Because the majority of this patient population consists of young women, it is important to note that the dimensions of the true pelvis and thus the potential for future vaginal delivery are preserved.

High-grade metachronous osteosarcoma. A case report over a 23-year period

This is a case report on the remarkable 23-year course of a metachronous osteogenic sarcoma in a 31-year-old man. Histology invariably showed the features of a high-grade osteogenic sarcoma with predominantly chondroblastic cells. During the observed period the patient developed nine osseous metastases. The quiescent clinical course of some metastases was in sharp contrast to the histological pattern. The patient finally died from symptoms of increasing cervical spinal cord compression without ever developing lung metastases.

Intraoperative electromyography of the superior gluteal nerve during lateral approach to the hip for arthroplasty: a prospective study of 12 patients

The purpose of this study was to evaluate the incidence of intraoperative superior gluteal nerve irritation and to identify specific surgical maneuvers that may harm the nerve. Continuous intraoperative electromyography (EMG) monitoring of the superior gluteal nerve-innervated muscles (gluteus medius and tensor fascia lata muscles) was performed in 12 patients undergoing total hip arthroplasty. A modified lateral approach was used, including a partial anterior osteotomy of the greater trochanter with splitting of the gluteus medius and vastus lateralis muscles. All patients had a clinical follow-up examination 1 year postoperatively to evaluate abductor muscle function. Irritation of the nerve occurred first during splitting of the gluteus medius muscle, then with increased gluteus medius retraction for exposure of the acetabulum, and finally during positioning of the leg for preparation of the femur. The detected EMG alterations were important because they were found in a single patient with persistent abductor muscle weakness.

The evolution of indirect reduction techniques for the treatment of fractures

During the last decade, classic AO/ASIF techniques for internal fixation shifted from direct reduction and rigid fixation to biologic internal fixation using indirect reduction techniques. Biologic internal fixation is characterized by the preservation of bone and soft tissue vascularity and relative rather than absolute mechanical stability. Reduction is achieved by using soft tissue traction while obtaining axial and rotational alignment and the correct length. Stabilization is performed when possible by compression plating for load sharing or by bridge plating in comminuted fractures. Advancements of these techniques and the development of newer implants that minimize vascular damage have contributed to the development of biologic internal fixation. By using indirect reduction, by using longer plates to improve the mechanical leverage, and by applying fewer screws to avoid unnecessary damage to the bone, fracture union rates were high. There also was a decreased need for supplemental bone grafting. All of these factors provided stable fixation and allowed early motion.

Unexpected resection of soft-tissue sarcoma. More mutilating surgery, higher local recurrence rates, and obscure prognosis as consequences of improper surgery

Sixteen referred patients were reviewed after excision of an unexpected soft-tissue sarcoma of the extremities. Eight tumors were located in the muscle deep to the fascia, and 8 lesions exceeded the size of 5 cm. The lack of awareness by the primary physician towards the possibility of a malignant lesion was striking, although 11 of 16 tumors presented as a newly formed mass. No imaging studies were done in 11 patients. Fine needle biopsy was unsuccessfully performed in 3 patients. Eleven lesions (63%) were high-grade. Resection margins were intralesional in 12 (75%) and marginal in 4 (25%) patients. Surgical oncologic rules were disregarded in 7 cases, including opening of probably uninvolved joints. Postoperative magnetic resonance imaging (MRI) scans showed a poor negative predictive value for residual tumor. Repeated resection, including three amputations, revealed residual tumor in 10 patients (63%). Four patients received adjuvant local radiation, with additional chemotherapy in 2 of them. At an average follow-up of 4.5 years (range 15-149 months), 4 patients (25%) had developed distant metastases with a local recurrence in 3 (19%). There was one tumor-related death (6%). Physicians' alertness towards the possible malignancy of an enlarging mass cannot be overemphasized. Evaluation by adequate imaging techniques, biopsy, and definitive resection and reconstruction should be performed by an oncologically trained orthopaedic surgeon. Inadequate primary excision leads to a high local recurrence rate and more mutilating surgery and obscures the long-term prognosis.

Indirect reduction with a condylar blade plate for osteosynthesis of subtrochanteric femoral fractures

Subtrochanteric fractures frequently occur as high energy trauma usually in younger patients and may lead to severe comminution of the medial cortex. The medial cortex of the proximal femur is exposed to high compressive forces which make fracture stabilization a difficult problem. Bone healing may be seriously compromised due to extensive comminution and fragment devitalization. This requires reduction techniques which do not cause additional damage to the vitality of the bone. With indirect reduction techniques and the use of a condylar blade plate the results have been significantly improved in these fracture types in our department (1). In this report the essential aspects of indirect reduction for subtrochanteric fractures using a condylar blade plate and the treatment results from our department from earlier years (1) and from the last 2 1/2 years will be presented. In the latter period, fifteen patients with a mean age of 49 years (19-87 years) were treated with this method. Fractures resulted from traffic incidents or falls from a great height in 11 cases (73%). Union was achieved in 14 cases (93%) with full weight-bearing after a mean of 3 months (1-4 1/2 months). Malunion was seen in two cases (13%) without the need for further surgery. Non union occurred in one patient (7%) with a III B open injury due to early infection. After repeated debridements, bone grafting and decortication, the fracture was stabilized with a replacement condylar blade plate and healed uneventfully.

Trochanteric flip osteotomy for cranial extension and muscle protection in acetabular fracture fixation using a Kocher-Langenbeck approach

OBJECTIVE

To describe the advantages and surgical technique of a trochanteric flip osteotomy in combination with a Kocher-Langenbeck approach for the treatment of selected acetabular fractures.

DESIGN

Consecutive series, teaching hospital.

METHODS

Through mobilization of the vastus lateralis muscle, a slice of the greater trochanter with the attached gluteus medius muscle can be flipped anteriorly. The gluteus minimus muscle can then be easily mobilized, giving free access to the posterosuperior and superior acetabular wall area. Damage to the abductor muscles by vigorous retraction can be avoided, potentially resulting in less ectopic ossification. Ten consecutive cases of acetabular fractures treated with this approach are reported. In eight cases, an anatomic reduction was achieved; in the remaining two cases with severe comminution, the reduction was within one to three millimeters. The trochanteric fragment was fixed with two 3.5-millimeter cortical screws.

RESULTS

All osteotomies healed in anatomic position within six to eight weeks postoperatively. Abductor strength was symmetric in eight patients and mildly reduced in two patients. Heterotopic ossification was limited to Brooker classes 1 and 2 without functional impairment at an average follow-up of twenty months. No femoral head necrosis was observed.

CONCLUSION

This technique allows better visualization, more accurate reduction, and easier fixation of cranial acetabular fragments. Cranial migration of the greater trochanter after fixation with two screws is unlikely to occur because of the distal pull of the vastus lateralis muscle, balancing the cranial pull of the gluteus medius muscle.