Computer-assisted femoral head reduction osteotomies: an approach for anatomic reconstruction of severely deformed Legg-Calvé-Perthes hips. A pilot study of six patients

BACKGROUND

Legg-Calvé-Perthes (LCP) is a common orthopedic childhood disease that causes a deformity of the femoral head and to an adaptive deformity of the acetabulum. The altered joint biomechanics can result in early joint degeneration that requires total hip arthroplasty. In 2002, Ganz et al. introduced the femoral head reduction osteotomy (FHRO) as a direct joint-preserving treatment. The procedure remains one of the most challenging in hip surgery. Computer-based 3D preoperative planning and patient-specific navigation instruments have been successfully used to reduce technical complexity in other anatomies. The purpose of this study was to report the first results in the treatment of 6 patients to investigate whether our approach is feasible and safe.

METHODS

In this retrospective pilot study, 6 LCP patients were treated with FHRO in multiple centers between May 2017 and June 2019. Based on patient-specific 3D-models of the hips, the surgeries were simulated in a step-wise fashion. Patient-specific instruments tailored for FHRO were designed, 3D-printed and used in the surgeries for navigating the osteotomies. The results were assessed radiographically [diameter index, sphericity index, Stulberg classification, extrusion index, LCE-, Tönnis-, CCD-angle and Shenton line] and the time and costs were recorded. Radiologic values were tested for normal distribution using the Shapiro-Wilk test and for significance using Wilcoxon signed-rank test.

RESULTS

The sphericity index improved postoperatively by 20% (p = 0.028). The postoperative diameter of the femoral head differed by only 1.8% (p = 0.043) from the contralateral side and Stulberg grading improved from poor coxarthrosis outcome to good outcome (p = 0.026). All patients underwent acetabular reorientation by periacetabular osteotomy. The average time (in minutes) for preliminary analysis, computer simulation and patient-specific instrument design was 63 (±48), 156 (±64) and 105 (±68.5), respectively.

CONCLUSION

The clinical feasibility of our approach to FHRO has been demonstrated. The results showed significant improvement compared to the preoperative situation. All operations were performed by experienced surgeons; nevertheless, three complications occurred, showing that FHRO remains one of the most complex hip surgeries even with computer assistance. However, none of the complications were directly related to the simulation or the navigation technique.

Findings and Management of the Rare Caput Flexum Deformity of the Hip: A Case Report

CASE

A 10-year-old girl presented after possible occult hip trauma, with shortening of the leg being the initial clinical symptom, followed by motion-dependent pain. She had limited external rotation in extension with anterior apprehension. Radiographically, the deformity was an anterior tilt of the epiphysis with coxa vara. Surgery included surgical dislocation using a retinacular flap for the anterior open wedge femoral neck osteotomy for extension and posterior translation, with an excellent 4.5-year clinical outcome.

CONCLUSIONS

Caput flexum is a rare deformity with localized premature closure of the anterior growth plate of the hip. To avoid secondary impingement, an osteotomy was successfully placed close to the deformity.

Femoral and acetabular re-alignment in slipped capital femoral epiphysis

NEW PATHOPHYSIOLOGICAL INSIGHTS

Based on improved knowledge of the vascular supply of the proximal femur, a safe surgical dislocation of the hip joint was established allowing direct insights to the pathomorphological malfunctioning of the joint. One insight was that slipped capital femoral epiphysis (SCFE) impingement leads to substantial damage of the chondrolabral rim area, even in the presence of minor slips. A further surgical development was the extended retinacular flap allowing for correction of the deformity with calculable risk for iatrogenic necrosis.

CONSECUTIVE SURGICAL CONCEPT

In 20 years of experience, a treatment concept for SCFE could be established which replaces classic pinning in situ and indirect correction of the deformity with subcapital re-alignment when the physis is still open, with true femoral neck osteotomy for hips with closed physis. Pinning in situ still has a place in minor slips but should be combined with open or arthroscopic recreation of an anterior metaphyseal waisting.

UNEXPECTED COMPLICATION

Loss of joint stability is a rare complication of anatomic re-alignment. It can be disease-related when the impingement has induced severe destruction of acetabular cartilage. It can be related to the surgical procedure, especially when the neck was excessively shortened and refixation of the trochanter was not advanced. Finally, in cases with severe and long-lasting deformity, the acetabulum may undergo adaptive flattening, being the cause of joint destabilisation with the correction of the deformity. Advancement of the greater trochanter and/or peri-acetabular osteotomy may be discussed to restabilise the joint.

Instability of the hip after anatomical re-alignment in patients with a slipped capital femoral epiphysis

AIMS

Several studies have reported the safety and efficacy of subcapital re-alignment for patients with slipped capital femoral epiphysis (SCFE) using surgical dislocation of the hip and an extended retinacular flap. Instability of the hip and dislocation as a consequence of this surgery has only recently gained attention. We discuss this problem with some illustrative cases.

MATERIALS AND METHODS

We explored the literature on the possible pathophysiological causes and surgical steps associated with the risk of post-operative instability and articular damage. In addition, we describe supplementary steps that could be used to avoid these problems.

RESULTS

The causes of instability may be divided into three main groups: the first includes causes directly related to SCFE (acetabular labral damage, severe abrasion of the acetabular cartilage, flattening of the acetabular roof and a bell-shaped deformity of the epiphysis); the second, causes not related to the SCFE (acetabular orientation and poor quality of the soft tissues); the third, causes directly related to the surgery (capsulotomy, division of the ligamentum teres, shortening of the femoral neck, pelvi-trochanteric impingement, previous proximal femoral osteotomy and post-operative positioning of the leg).

CONCLUSION

We present examples drawn from our clinical practice, as well as possible ways of reducing the risks of these complications, and of correcting them if they happen. Cite this article: Bone Joint J 2017;99-B:16-21.

Reducing the risk of nerve injury during Bernese periacetabular osteotomy

The modified Smith–Petersen and Kocher–Langenbeck approaches were used to expose the lateral cutaneous nerve of the thigh and the femoral, obturator and sciatic nerves in order to study the risk of injury to these structures during the dissection, osteotomy, and acetabular reorientation stages of a Bernese peri-acetabular osteotomy.

Injury of the lateral cutaneous nerve of thigh was less likely to occur if an osteotomy of the anterior superior iliac spine had been carried out before exposing the hip.

The obturator nerve was likely to be injured during unprotected osteotomy of the pubis if the far cortex was penetrated by > 5 mm. This could be avoided by inclining the osteotome 45° medially and performing the osteotomy at least 2 cm medial to the iliopectineal eminence.

The sciatic nerve could be injured during the first and last stages of the osteotomy if the osteotome perforated the lateral cortex of ischium and the ilio-ischial junction by > 10 mm.

The femoral nerve could be stretched or entrapped during osteotomy of the pubis if there was significant rotational or linear displacement of the acetabulum. Anterior or medial displacement of < 2 cm and lateral tilt (retroversion) of < 30° were safe margins. The combination of retroversion and anterior displacement could increase tension on the nerve.

Strict observation of anatomical details, proper handling of the osteotomes and careful manipulation of the acetabular fragment reduce the neurological complications of Bernese peri-acetabular osteotomy.

Cite this article: Bone Joint J 2015;97-B:636–41.

The evolution and concepts of joint-preserving surgery of the hip

The use of joint-preserving surgery of the hip has been largely abandoned since the introduction of total hip replacement. However, with the modification of such techniques as pelvic osteotomy, and the introduction of intracapsular procedures such as surgical hip dislocation and arthroscopy, previously unexpected options for the surgical treatment of sequelae of childhood conditions, including developmental dysplasia of the hip, slipped upper femoral epiphysis and Perthes’ disease, have become available. Moreover, femoroacetabular impingement has been identified as a significant aetiological factor in the development of osteoarthritis in many hips previously considered to suffer from primary osteoarthritis.

As mechanical causes of degenerative joint disease are now recognised earlier in the disease process, these techniques may be used to decelerate or even prevent progression to osteoarthritis. We review the recent development of these concepts and the associated surgical techniques.

Cite this article: Bone Joint J 2014;96-B:5–18.

Prevalence of cam and pincer-type deformities on hip MRI in an asymptomatic young Swiss female population: a cross-sectional study

OBJECTIVES

Femoroacetabular impingement is proposed to cause early osteoarthritis (OA) in the non-dysplastic hip. We previously reported on the prevalence of femoral deformities in a young asymptomatic male population. The aim of this study was to determine the prevalence of both femoral and acetabular types of impingement in young females.

METHODS

We conducted a population-based cross-sectional study of asymptomatic young females. All participants completed a set of questionnaires and underwent clinical examination of the hip. A random sample was subsequently invited to obtain magnetic resonance images (MRI) of the hip. All MRIs were read for cam-type deformities, increased acetabular depths, labral lesions, and impingement pits. Prevalence estimates of cam-type deformities and increased acetabular depths were estimated, and relationships between deformities and signs of joint damage were examined using logistic regression models.

RESULTS

The study included 283 subjects, and 80 asymptomatic females with a mean age of 19.3 years attended MRI. Fifteen showed some evidence of cam-type deformities, but none were scored to be definite. The overall prevalence was therefore 0% [95% confidence interval (95% CI) 0-5%]. The prevalence of increased acetabular depth was 10% (95% CI 5-19). No association was found between increased acetabular depth and decreased internal rotation of the hip. Increased acetabular depth was not associated with signs of labral damage.

CONCLUSIONS

Definite cam-type deformities in women are rare compared to men, whereas the prevalence of increased acetabular depth is higher, suggesting that femoroacetabular impingement has different gender-related biomechanical mechanisms.

[The trochanteric flip osteotomy.]

GOAL OF SURGERY

Easy access to the posterior, superior and anterior joint capsule through an osteotomy which reduces the risk of complications and the incidence of non-union.

INDICATIONS

Hip joint revision with or without intertrochanteric osteotomy, periarticular ossifications, difficult total hip procedures, exchange procedures.

CONTRAINDICATIONS

Absolute: None Relative: Distal transfer of the trochanter.

PREOPERATIVE WORK UP

Radiographs in 2 planes (anterior-posterior pelvis+"false profile" hip).

POSITIONING AND ANAESTHESIA

Lateral decubitus. General anaesthesia.

SURGICAL TECHNIQUE

In lateral decubitus the greater trochanter will be osteotomized from posterior leaving a 1 to 1.5 cm thick bony wafer uniting the insertion of the gluteus medius and minimus with the origin of the vastus lateralis. The trochanteric crest remains untouched. After refixation with nonresorbable sutures #3 the fragment is not subjected to a unidirectional tension by the abductors which could interfere with the consolidation.

POSTOPERATIVE MANAGEMENT

Bed rest with lower limb in neutral position. Mobilization with 2 canes on the 2nd postoperative day. The timing of partial weight bearing depends on the type of surgery. Abductor exercises after 6 weeks.

POSSIBLE COMPLICATIONS

Bony wafer too thin or too thick. Inadequate refixation. Delayed consolidation. Cranial migration of the greater trochanter.

RESULTS

Between 1991 and 1994 41 patients were operated. Diagnoses, see Table 1. Method of refixation: see Table 2. After 21+/-9 months 39 patients could be reexamined clinically, and radiological after 17+/-11 months: 38 osteotomies consolidated. Cranial migration varied between 0 and 8 mm. 25 patients were free of symptoms, 12 had slight and 2 moderate pain over the trochanter. Avulsion of wire cerclage: 2, foreign body irritation: 2 necessitating implant removal.

Utilization of wireless pH monitoring technologies: a summary of the proceedings from the esophageal diagnostic working group

Gastroesophageal reflux disease (GERD) can be difficult to diagnose - symptoms alone are often not enough, and thus, objective testing is often required. GERD is a manifestation of pathologic levels of reflux into the esophagus of acidic, nonacidic, and/or bilious gastric content. However, in our current evidence-based knowledge approach, we only have reasonable outcome data in regards to acid reflux, as this particular type of refluxate predictably causes symptoms and mucosal damage, which improves with medical or surgical therapy. While there are data suggesting that nonacid reflux may be responsible for ongoing symptoms despite acid suppression in some patients, outcome data about this issue are limited. Therefore, this working group believes that it is essential to confirm the presence of acid reflux in patients with 'refractory' GERD symptoms or extraesophageal symptoms thought to be caused by gastroesophageal reflux before an escalation of antireflux therapy is considered. If patients do not have pathologic acid reflux off antisecretory therapy, they are unlikely to have clinically significant nonacid or bile reflux. Patients who do not have pathologic acid gastroesophageal reflux parameters on ambulatory pH monitoring then: (i) could attempt to discontinue antisecretory medications like proton pump inhibitors and H2-receptor antagonists (which are expensive and which carry risks - i.e. C. diff, etc.); (ii) may undergo further evaluation for other causes of their esophageal symptoms (e.g. functional heartburn or chest pain, eosinophilic esophagitis, gastroparesis, achalasia, other esophageal motor disorders); and (iii) can be referred to an ear, nose, and throat/pulmonary/allergy physician for assessment of non-GERD causes of their extraesophageal symptoms.

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.

Hip resurfacing arthroplasty: current status and future perspectives

Hip resurfacing arthroplasty (HRA) is a concept of hip replacement that allows treating young active patients with a femoral bone preserving procedure. The proposed advantages of resuming an active lifestyle with increased frequency and duration of sports activities have been shown to be realistic. The 30-year cost-effectiveness in young male patients has been shown to be higher in resurfacing compared to conventional total hip replacement (THA). However, prognosticators of an inferior outcome have also been identified. The most important patient related factors are secondary osteoarthritis as the indication for surgery such as post-childhood hip disorders or AVN, female gender, smaller component sizes and older age (>65 years for males and >55 years for females). In addition, surgical technique (approach and cementing technique) and component design are also important determinant factors for the risk of failure. Moreover, concerns have surfaced with respect to high metal ion concentrations and metal ion hypersensitivities. In addition, the presumed ease of revising HRA has not reflected in improved or equal survivorship in comparison to a primary THA. This highlights the importance of identifying patient-, surgery-, and implant-related prognosticators for success or failure of HRA. Rather than vilifying the concept of hip resurfacing, detailed in depth analysis should be used to specify indications and improve implant design and surgical techniques.

Histopathology of Cryopreserved Bone Allo- and Isografts: Pretreatment with Dimethyl Sulfoxide

Partial graft cell survival and enhanced graft revascularization have suggested fast freezing using the cryoprotective substance dimethyl sulfoxide (DMSO) as a promising means to improve the biologic function and immune tolerance of allograft bone. This study determines the presence of osteoblasts (cola(1)(I) mRNA), osteoclasts (TRAP), and cytotoxic T cells (CTLs; GrA mRNA) within pretreated bone grafts 12 days after transplantation. The grafts were transplanted either as isografts, allografts, or allografts in presensitized recipients. In fresh isografts, serving as control, well-formed blood vessels and the highest numbers of viable osteoblasts and osteoclasts were found. In fresh allografts, blood vessels were observed within the marrow cavity and the bone was partially covered by osteoblasts and osteoclasts accompanied by CTLs. In DMSO-pretreated frozen allografts, blood vessels together with osteoblasts were observed in three of five, but in none of five grafts frozen without DMSO. However, infiltration with CTLs was higher in DMSO-pretreated frozen allografts when compared to grafts frozen without DMSO. In presensitized allograft recipients, independent of the pretreatment, in none of the grafts were either blood vessels or osteoblasts found. Thus, fast cryopreservation of bone using DMSO improves vascularization and expression of cola(1)(I) mRNA (osteoblasts) after allografting when compared to cryopreservation alone, potentially improving graft incorporation. As these grafts were still invaded by CTLs, the long-term effect of DMSO pretreatment needs to be defined.

Differential response of porcine osteoblasts and chondrocytes in cell or tissue culture after 5-aminolevulinic acid-based photodynamic therapy

OBJECTIVE

Outcome in osteochondral allografting is limited by the immunological incompatibility of the grafted tissue. Based on a resistance of chondrocytes to photodynamic therapy in cell culture it is proposed that 5-aminolevulinic acid-based photodynamic therapy (5-ALA-PDT) might be used to inactivate bone while maintaining viability of chondrocytes and thus immunomodulate bone selectively.

METHODS

Chondrocytes and osteoblasts from porcine humeral heads were either isolated (cell culture) or treated in situ (tissue culture). To quantify cytotoxic effects of 5-ALA-PDT (0-20 J/cm(2), 100 mW/cm(2)) an (3-(4,5-dimethylthiazol-2-yl)-2,5-di-phenyltetrazolium bromide) (MTT)-assay was used in cell culture and in situ hybridization in tissue culture to assess metabolic active cells (functional osteoblasts: col alpha(1)(I) mRNA, functional chondrocytes: col alpha(1)(II) mRNA).

RESULTS

In cell culture, survival after 5-ALA-PDT was significantly higher for chondrocytes (5 J/cm(2): 87+/-12% compared to untreated cells) than for osteoblasts (5J/cm(2): 12+/-11%). In tissue culture, the percentage of functional chondrocytes in cartilage showed a decrease after 5-ALA-PDT (direct fixation: 92+/-2%, 20 J/cm(2): 35+/-15%; P<0.0001). A significant decrease in the percentage of bone surfaces covered by functional osteoblasts was observed in freshly harvested (31+/-3%) compared to untreated tissues maintained in culture (11+/-4%, P<0.0001), with no further decrease after 5-ALA-PDT.

CONCLUSION

Chondrocytes were more resistant to 5-ALA-PDT than osteoblasts in cell culture, while in tissue culture a loss of functional chondrocytes was observed after 5-ALA-PDT. Since osteoblasts - but not chondrocytes - were sensitive to the tissue culture conditions, devitalized bone with functional cartilage might already be achieved by applying specific tissue culture conditions even without 5-ALA-PDT.

Construct validity of a 12-item WOMAC for assessment of femoro-acetabular impingement and osteoarthritis of the hip

OBJECTIVE

Evaluation of the internal construct validity of the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index adapted for use in patients with femoro-acetabular impingement (FAI) and osteoarthritis (OA) of the hip.

METHODS

Distribution of a German version of WOMAC to patients upon first consultation. Patients with FAI [n=100, mean age 31.7 years, standard deviation (SD) 9.7] and OA (n=57, mean age 60.3 years, SD 11.7) and without comorbidities or prior hip surgery were included and compared to age- and gender-matched control population to FAI (n=200, mean age 32.6 years, SD 5.6). WOMAC data of 157 questionnaires were evaluated by Rasch analysis using RUMM2020 software.

RESULTS

Summation of total WOMAC shows misfit to the Rasch model as well as multidimensionality. While the pain subset shows adequate fit and is unidimensional, item reduction is required to fit a unidimensional subset of functional items to the Rasch model. Summating the two fitting subsets yields again slight model misfit and multidimensionality requiring further item reduction. Finally, a 12-item version of the total WOMAC shows good model fit and unidimensionality, i.e., internal construct validity, for assessment of patients with FAI and OA without differential item functioning (DIF). A person separation index (PSI)=0.93 indicates a high internal consistency reliability for the 12-item subscale. Scores for FAI are significantly higher than control (P<0.001, effect size 0.71) and lower than OA group (P<0.001, effect size 0.45). Adequate statistical power is shown discriminating the three groups, therefore indicating some evidence also for external construct validity.

CONCLUSIONS

The WOMAC as a total construct is multidimensional and summating the subsets into a total score is not valid. The reduced 12-item WOMAC is demonstrated to have internal construct validity for assessing patients with FAI and OA on the same scale and high internal consistency reliability. Discrimination of the groups with adequate statistical power also indicates external construct validity.

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.

Os acetabuli in femoro-acetabular impingement: stress fracture or unfused secondary ossification centre of the acetabular rim?

Ossicles located at the acetabular rim are generally referred to as unfused secondary ossification centres and are named "os acetabuli". They are also observed in severely dysplastic hips, where they are considered as fatigue fractures of the acetabular rim due to overload. In a retrospective study, we evaluated the radiographs of 495 patients, who were treated surgically for femoro-acetabular impingement. In 18 hips (15 patients) a large osseous fragment at the anterolateral acetabular rim was found. All patients presented radiographically with a femoral head showing an aspherical extension producing a "cam" impingement. Sixteen hips had a retroverted acetabulum, indicating anterior overcover. Preoperative MRIs available in 12 patients showed the presence of a fragment composed of labrum, articular cartilage and bone. The gap between the stable acetabulum and the rim fragment had a vertical orientation. All patients had been exposed to a physically demanding profession or contact sport and in 15 hips no memorable traumatic episode was present. The mechanism leading to this acetabular rim fragment is thought to be fatiguing due to femoro-acetabular impingement. The aspheric portion of the head is jammed into the acetabulum and with time causes a stress fracture of the retroverted portion of the acetabulum. True "Os acetabuli" are morphologically similar, but the orientation of the cartilaginous growth plate is more parallel to the joint surface, in contrast to the hips in the current study, where the separation line was perpendicular to the joint surface. The clinical importance is that the presence of an acetabular rim fragment in the non-dysplastic hip must raise suspicion of femoro-acetabular impingement.;

Evaluation and treatment of young adults with femoro-acetabular impingement secondary to Perthes' disease

Hip pain and loss of motion in young adults with previous Legg-Calve-Perthes-Disease may be caused by anterior femoro-acetabular impingement. Eleven patients (12 hips) with the chief complaint of groin pain and significant proximal femoral deformity were treated. Gadolinium-enhanced magnetic resonance arthrography in ten patients indicated labral injury and adjacent acetabular cartilage lesions in nine hips. A surgical dislocation of each hip confirmed that there was impingement induced intra-articular injury consistent with the pathology indicated on the MRI. Reshaping of the femoral head, with correction of the femoral head/neck offset, and treatment of the acetabular rim pathology was performed for each hip in conjunction with other procedures for the proximal femur. Correction of the impingement and increased range of motion could be visualized intra-operatively. At a mean follow-up of 33 months, half of all patients were pain-free and all had improvement in pain compared with preoperatively. Ten patients had an improved range of motion and two a slight decrease. No additional necrosis following the dislocation of the femoral head was seen.;

Acetabular dome retroversion: radiological appearance, incidence and relevance

Interest in acetabular version arose from the study of unstable developmental dysplastic hips (DDH). Initial studies and clinical observations described the dysplastic hip as being excessively anteverted. Doubts on this view arose from analysis of complications such as persistent posterior subluxation after acetabular reorienting procedures. Computed tomography fails to determine conclusively whether or not the dysplastic acetabulum is abnormally anteverted. Controversy evolves from different methods of measuring and from the fact that the acetabular opening gradually spirals from mild anteversion proximally to increasing anteversion distally. This renders the measurement of version dependent on pelvic inclination and the level of the transverse CT scan slice. On an orthograde pelvic radiograph, both pelvic inclination and rotation can be controlled. Therefore, acetabular version is best estimated based on the relationship of the anterior and posterior acetabular rims to each other on an orthograde pelvic radiograph. Acetabular retroversion has been found to be a characteristic feature of specific hip disorders such as post-traumatic dysplasia, proximal femoral focal deficiency and bladder exstrophy. In addition, acetabular retroversion has been described in DDH as well as in dysplastic hips in the context of neuromuscular and genetic disorders. Iatrogenic acetabular retroversion can also result from corrective pelvic osteotomies in childhood. Finally, retroverted acetabula may be found in otherwise nondysplastic hips. The relevance of acetabular retroversion is twofold: First, it demands a more individualized approach to acetabular dysplasia because the presence of retroversion will affect the manner in which the corrective osteotomy should be done. Second, the long-term effect of acetabular retroversion is harmful.

[Femoroacetabular impingement: trigger for the development of coxarthrosis]

Femoroacetabular impingement (FAI) is frequent; the estimated prevalence ranges between 10 and 15%. Our 10-years experience strongly suggests that FAI leads to osteoarthritis. Isolated acetabular or femoral abnormalities are rare, even though in women acetabular and in men femoral abnormalities predominate. Normal radiographs do not exclude the presence of FAI. Symptoms are related to the degree of deformity and occur earlier in the presence of activities requiring high levels of motion. The majority of patients with FAI are under the age of 40 years. In contrast to impingement in total hip replacement, the natural hip is under much higher constraint, not allowing to escape from impingement-induced shear forces by subluxation or complete dislocation. FAI-induced shear forces due to an aspherical femoral head/neck (cam type) are therefore high, causing outside-in damage with cleavage lesions of the acetabular cartilage by forced flexion and internal rotation. The cartilage of the femoral head remains initially intact, which cannot be explained by the classic concept of osteoarthritis. After the femoral head has migrated into the acetabular cartilage defect, vertical forces contribute to the further course of osteoarthritis. Tears between the labrum and cartilage, as seen by MRI, are not avulsions of the labrum from the cartilage but rather outside-in avulsions of the cartilage from the labrum. In acetabular overcoverage (pincer type) the labrum is the first structure to fail and acetabular cartilage damage develops thereafter. The treatment of FAI in patients under the age of 40 years is aimed at joint preservation. The clinical result is worse in the presence of significant cartilage damage. Therefore, early appreciation of FAI and timely therapeutic intervention as well as professional and athletic adjustment are important if osteoarthritis is to be prevented.

[Bilateral post-traumatic acetabular dysplasia]

Traumatic disruption of the acetabular triradiate cartilage is an infrequent injury. When it occurs in early childhood, it may lead to growth changes in acetabular morphology. The morphology of this kind of acetabular dysplasia is uniform and differs significantly from that seen in classic developmental dysplasia of the hip. We present a case of bilateral post-traumatic acetabular dysplasia, which to our knowledge has not been reported. The morphology and the symptoms of impingement and periacetabular osteotomy of the hip joint are discussed.

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.

Acetabular centre-edge angles revisited: applications and limitations in patients with acetabular dysplasia undergoing periacetabular osteotomy

This study evaluates the application and limitations of the acetabular centre-edge angles as described by Wiberg (LCE) and Lequesne (VCA) in a group of adult patients with acetabular dysplasia that were treated with periacetabular osteotomy. Fifty hips in patients with a mean age of 30 years (range, 17-45) were identified and a number of radiographic indices were compared pre and post osteotomy. The potential for measurement variation in both the LCE and VCA angle was evaluated and relationships between the centre-edge angles and other radiographic indices were determined. While all hips displayed some degree of lateral deficiency only 19 (40%) of these cases displayed a ''classic'' lateral and anterior deficiency while 12 (20%) were in fact retroverted. The mean VCA in hips with primarily anterior and lateral deficiency (-6.712.5) was significantly lower (p<0.01) than those with uniform deficiency (5.18.3) or those with retroverted acetabuli (8.913.3). Overall the mean VCA angle of 2.3 (SD12.7) and LCE angle of 3.4 (SD9.3) was corrected to 25.8 (SD11.6) and 28.6 (SD8.7) following osteotomy. The VCA and LCE angles were not correlated (r=0.35) and the LCE angle showed no significant correlation to other lateral coverage indices (Tnnis, Sharp). No correlation was seen either in the post osteotomy values, or in the absolute degree of correction. An alternate VCA (aVCA), identifying the most anterior aspect of the acetabular margin as the reference point, was significantly larger (p<0.001) but did correlate (r=0.77) with the traditional VCA. Potential sources of error in measurement were identified and are reviewed.

Experience with minimally invasive esophagectomy

BACKGROUND

Minimally invasive esophagectomy (MIE) is an evolving surgical alternative to traditional open esophagectomy. Despite considerable technical challenges, it was hypothesized that MIE could be performed effectively by surgeons experienced in open esophageal resection and advanced laparoscopic surgery. The authors report their experience with 25 patients who underwent MIE for esophageal disease.

METHODS

A multidisciplinary esophageal cancer team evaluated all the patients enrolled in this institutional review board-approved retrospective review study. Over an 18-month period, 25 consecutive patients (22 men and 3 women; mean age, 62 years; range, 48-77 years) with resectable esophageal cancer underwent MIE. Six patients were treated with neoadjuvant chemoradiotherapy. The preoperative diagnoses were adenocarcinoma (64%, n = 16), high-grade dysplasia (20%, n = 5), and squamous cell cancer (16%, n = 4). The outcomes evaluated included operative course, hospital and intensive care unit lengths of stay, pathologic stage, morbidity, and mortality.

RESULTS

Two patients required conversion to open esophagectomy. Operative mortality was 4% (n = 1). The mean operative time was 350 min (range, 300-480), and the average blood loss was 200 ml. The patients remained ventilated for a median of 12 h, and the median intensive care unit utilization was 1 day. The median hospital length of stay was 9 days (range, 6-33 days). Major complications occurred in 32% of the patients. The anastomotic leak rate was 12%. Minor pulmonary complications occurred in 32% and atrial fibrillation in 16% of the patients. An anastomotic stricture developed in 24% of all the patients. One patient showed a positive proximal margin in the final pathology results.

CONCLUSIONS

Minimally invasive esophagectomy is a technically challenging procedure that can be performed safely at the Virginia Piper Cancer Institute. Optimal results require appropriate patient selection and a multidisciplinary team experienced in the management of esophageal cancer.

[Anterior femoroacetabular impingement after healed femoral neck fractures]

OBJECTIVES

To describe anterior femoroacetabular Impingement (AFAI) as a cause of persistent painful loss of motion and progressive joint-destruction in patients with a healed femoral neck fracture, and to evaluate results after its surgical treatment.

METHODS

Eleven patients with groin pain elicited by motion and exertion following a healed femoral neck fracture were diagnosed clinically, by conventional radiographs and radial Arthro MRI with AFAI. During surgical subluxation or dislocation of the hip joint the impingement was visually verified and eliminated by re-shaping the anterior contour of the head-neck-junction.

RESULTS

All patients presented a flat contour of the anterior head-neck-junction causing a cam-type impingement with subsequent damage of the anterior-superior acetabular cartilage adjacent to the rim. These chondral changes result from the repetitive compression and shear forces between the flattened head-neck junction and the acetabular cartilage in flexion and internal rotation. At five year follow-up a clear improvement of the symptoms was observed without any signs of progressive joint destruction.

CONCLUSION

When chronic pain after a healed femoral neck fracture without necrosis of the femoral head occurs, the possibility of an AFAI caused by retrotorsion of the proximal fragment should be taken into consideration. The symptoms of AFAI can be relieved by surgical correction of the femoral head-neck-offset. The existing damage of the acetabular cartilage originated by the impingement at the time of surgery can hardly be improved. Therefore anatomical fracture reduction should be performed in order to prevent the development of osteoarthritis. Pre-existing deformities of the joint should be treated at the time of operative fracture treatment.

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.

Hip morphology influences the pattern of damage to the acetabular cartilage: femoroacetabular impingement as a cause of early osteoarthritis of the hip

Recently, femoroacetabular impingement has been recognised as a cause of early osteoarthritis. There are two mechanisms of impingement: 1) cam impingement caused by a non-spherical head and 2) pincer impingement caused by excessive acetabular cover. We hypothesised that both mechanisms result in different patterns of articular damage. Of 302 analysed hips only 26 had an isolated cam and 16 an isolated pincer impingement. Cam impingement caused damage to the anterosuperior acetabular cartilage with separation between the labrum and cartilage. During flexion, the cartilage was sheared off the bone by the non-spherical femoral head while the labrum remained untouched. In pincer impingement, the cartilage damage was located circumferentially and included only a narrow strip. During movement the labrum is crushed between the acetabular rim and the femoral neck causing degeneration and ossification. Both cam and pincer impingement lead to osteoarthritis of the hip. Labral damage indicates ongoing impingement and rarely occurs alone.

Femoroacetabul�res Impingement

The exact cause of the idiopathic osteoarthritis of the hip has not been identified, although the cause of hip degeneration in developmental dysplasia can clearly be attributed to an excessive axial loading. Based on the development of a surgical technique for the safe surgical dislocation of the hip and the associated possibility of intraoperative joint evaluation, we have found motion-induced joint damage in many of these hips. This begins peripherally at the acetabular rim, progressing centrally. This so-called "femoroacetabular impingement" (FAI), leads, by an increased acetabular coverage and/or a missing sphericity of the femoral head, to an abutment of the femoral head/neck junction against the acetabular rim, or even entering of the non-spherical femoral head into the hip. It initiates damage to the labrum and/or acetabular cartilage. Frequently, this becomes symptomatic in the second or third decade of life in patients with increased sport activity. Based on the predominance of the acetabular or femoral pathology, two different types of FAI, the pincer and the cam can be differentiated. Apart from these morphological alterations, supraphysiological mobility and overuse can contribute to FAI. The impingement concept has led to a new type of mainly intracapsular hip surgery.

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.

Femoroplasty-augmentation of mechanical properties in the osteoporotic proximal femur: a biomechanical investigation of PMMA reinforcement in cadaver bones

OBJECTIVE

To determine the feasibility of polymethyl-methacrylate injection into the osteoporotic proximal femur and its effect on the mechanical properties.

DESIGN

In vitro pairwise comparison of non reinforced and reinforced bones in a load to failure loading mode.

BACKGROUND

Hip fractures represent an important public healthcare problem. Continued growth in the elderly population will raise the incidence of hip fractures and their associated costs dramatically in the near future.

METHODS

Twenty pairs of osteoporotic femurs were mechanically tested either in a single-limb stance configuration or simulating a fall on the greater trochanter. From each pair, one femur was augmented with bone cement, with the contralateral femur serving as a control. The surface temperature at the femoral neck was recorded until twenty minutes after injection. The fracture load and the energy absorption were calculated. The Wilcoxon signed rank test was used to test for differences in fracture load and energy absorption between the reinforced femurs and the native controls.

RESULTS

Volumes of 28-41 ml of cement (mean, 36 ml) could be injected. The increase of surface temperature at the femoral neck ranged from delta18.4 to delta29.8 degrees C. For the single limb stance configurations, the peak fracture load was increased by 21%, (P < 0.002) and for the simulated fall on the hip by 82%, (P < 0.002). The corresponding values for energy absorption were +48%; and +188% (P < 0.002) respectively.

CONCLUSIONS

The feasibility and mechanical effectiveness of the in vitro procedure could be demonstrated. The heat generation due to polymethyl-methacrylate polymerisation is high.

RELEVANCE

Prophylactic reinforcement of the femur could become a treatment option to solve the problems with osteoporotic hip fractures in patients at risk. Reinforcement materials with less exothermic reaction need to be evaluated further and also the feasibility of fracture repair after reinforcement.

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.

The acetabular blood supply: implications for periacetabular osteotomies

As the popularity of juxta-acetabular osteotomies in adults increases, concern arises that such a procedure will potentially cause avascular necrosis of the acetabular fragment. In order to verify the remaining vascularization after a Bernese periacetabular osteotomy, an injection study with colored latex was performed. The vascularity of the outside of the periacetabular bone was studied in 16 hips after injection of colored latex into the abdominal aorta and the inside in four hips. To confirm the conclusions drawn from the anatomic study, a Bernese periacetabular osteotomy was performed in two additional hips after latex injection. This study demonstrated that through a modified Smith-Peterson approach and with execution of the osteotomies from the inside of the pelvis the acetabular fragment remains vascularized by the supra-acetabular and acetabular branches of the superior gluteal artery, the obturator artery and the inferior gluteal artery. Some uncertainty remains about how much correction is tolerated by the smaller blood vessels.

Endoscopic implantation of enteryx for treatment of GERD: 12-month results of a prospective, multicenter trial

OBJECTIVES

This study aimed to assess the efficacy and safety of endoscopically implanting a nonresorbable biocompatible polymer (Enteryx) in the distal esophagus and proximal gastric cardia for the treatment of gastroesophageal reflux disease (GERD).

METHODS

In a prospective, multicenter, international trial, 85 well-controlled GERD patients who were receiving chronic proton pump inhibitor (PPI) therapy underwent Enteryx implantation under fluoroscopic visualization, without general anesthesia. After the procedure, patients were discharged within approximately 2-4 h. Patients were judged to be treatment responders if after implantation they reduced PPI dosage by >/=50%. Follow-up evaluations were conducted at 1, 3, 6, and 12 months and included medication usage, symptoms, quality of life, endoscopy, pH monitoring, manometry, and documentation of adverse events.

RESULTS

At 12 months, 80.3% (95% CI = 69.9%-88.3%) of 81 evaluable patients were treatment responders. Of the responders, 87.7% completely discontinued PPIs, and 12.3% reduced PPI dosage by >/=50%. Treatment response was more likely in patients with residual implant volume of >/=5 mL (p = 0.027). Other patient and treatment variables were not predictive. Both GERD heartburn and regurgitation symptom scores significantly improved at 12 months compared with baseline (p < 0.001). There were significant reductions in median supine, upright, and total percent time of esophageal exposure to pH <4. Endoscopically assessed esophagitis grades were unchanged. No serious adverse events were encountered. Transient retrosternal chest pain was experienced by 91.8% of patients. This pain was seldom severe and was typically successfully managed with prescription pain medication.

CONCLUSIONS

Enteryx implantation allows most patients to discontinue PPI therapy, improves their symptoms, and reduces esophageal acid exposure. The effects of implantation are long-lasting, and morbidity is transient and minimal. The procedure requires basic endoscopic skills and seems to provide a useful option in the effective clinical management of GERD.

Cryopreservation with dimethyl sulfoxide sustains partially the biological function of osteochondral tissue

The clinical routine use of bone allograft transplants dates back to the discovery that grafts devitalized by freezing bear a reduced antigenicity. Graft failures, caused by a host versus graft reaction, however, remain a clinical problem. Previous investigations on pancreatic islet allografts revealed improved survival and biological function when fast cryopreservation (-70 degrees C/min) was performed in the presence of dimethyl sulfoxide (DMSO). The aim of this study was to determine the effect of fast freezing using DMSO on the biological function of osteochondral tissues. Organ culture was performed with neonatal femora of mice, untreated, rapidly frozen (-70 degrees C/min) with DMSO, or frozen without DMSO. After the culture, tissue morphology, cellular proliferation, osteoblast function, osteoclasts, and the presence of antigen-presenting cells were investigated. In untreated control femora histology appeared normal and proliferating and collagen-synthesizing osteoblasts, osteoclasts, and B-cells and macrophages were present. In frozen femora (with and without DMSO) a disintegration of the periosteum and the epiphyseal growth plate were observed and no active osteoblasts could be detected. Osteoclasts were partially detached from the bone surface. Cell proliferation was fully blocked in femora frozen in the absence of DMSO, while freezing in the presence of DMSO preserved cell proliferation in the medullary canal. The proliferating cells do not express epitopes present on the cells of the B-cell or macrophage lineages. Although the biological function of osteoblasts and osteoclasts was lost upon freezing of osteochondral tissue, DMSO included in freezing protocols preserves some residual cell viability which may be of importance for early graft revascularization as has been previously demonstrated by our group.

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.

Partial anterior trochanteric osteotomy in total hip arthroplasty: surgical technique and preliminary results of 127 cases

The authors describe a new approach to the hip joint arthroplasty performed in 127 cases of total hip arthroplasty without major complication. A small anterior fragment of greater trochanter, maintaining the insertions of the gluteus minimus and vastus lateralis muscles, is detached. The whole insertion of the gluteus medius is preserved intact, providing good prosthetic stability and rapid recovery of abductor power and gait. Three months after surgery, 74% of patients had recovered good abductor strength with a Merle d'Aubigné and Postel score of 17 points. This surgical approach is technically easy to perform and provides good exposure of the hip. The osteotomized fragment is easily reattached using 2 cerclage wires, and upward displacement after operation was rarely seen.

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.

Endoscopic, deep mural implantation of Enteryx for the treatment of GERD: 6-month follow-up of a multicenter trial

OBJECTIVES

This prospective, multicenter, single-arm study evaluated the safety and efficacy of the endoscopic implantation of Enteryx, a biocompatible, non-biodegradable liquid polymer for the treatment of GERD.

METHODS

Eighty-five patients with heartburn symptoms responsive to proton pump inhibitor (PPI) use were enrolled. Inclusion requirements were HRQL score < or = 11 on PPI and > or = 20 off PPI, and 24-hour PH probe with > or = 5% total time at PH < or = 4. Patients with a hiatus hernia > 3 cm, grade 3 or 4 esophagitis, or esophageal motility disorder were excluded. Using a 4-mm needle tipped catheter during standard endoscopy, implants were made in 3-4 quadrants deep into the wall of the cardia. Use of PPI medications, pH-metry, manometry, GERD symptoms, and patient quality of life were assessed over a 6-month follow-up period.

RESULTS

At 6 months, PPI use was eliminated in 74% and reduced by > 50% in 10% of patients. The median HRQL score improved from 24.0 pre-implant (baseline off PPIs) to 4.0 at 6 months (p < 0.001). Mean total esophageal acid exposure time was 9.5% pretherapy and 6.7% at 6 months (p < 0.001). Mean LES length increased from 2.0 cm at baseline to 3.0 cm posttherapy (p = 0.003). There were no clinically serious adverse events. Transient mild-to-moderate chest pain commonly occurred after implantation.

CONCLUSIONS

The endoscopic implantation of Enteryx is a safe and effective therapy for eliminating or decreasing the need for PPI medications, improving GERD symptoms and patient quality of life, and decreasing esophageal acid exposure among patients suffering from GERD.

An in vitro investigation of the acetabular labral seal in hip joint mechanics

Labrum pathology may contribute to early joint degeneration through the alteration of load transfer between, and the stresses within, the cartilage layers of the hip. We hypothesize that the labrum seals the hip joint, creating a hydrostatic fluid pressure in the intra-articular space, and limiting the rate of cartilage layer consolidation. The overall cartilage creep consolidation of six human hip joints was measured during the application of a constant load of 0.75 times bodyweight, or a cyclic sinusoidal load of 0.75+/-0.25 times bodyweight, before and after total labrum resection. The fluid pressure within the acetabular was measured. Following labrum resection, the initial consolidation rate was 22% greater (p=0.02) and the final consolidation displacement was 21% greater (p=0.02). There was no significant difference in the final consolidation rate. Loading type (constant vs. cyclic) had no significant effect on the measured consolidation behaviour. Fluid pressurisation was observed in three of the six hips. The average pressures measured were: for constant loading, 541+/-61kPa in the intact joint and 216+/-165kPa following labrum resection, for cyclic loading, 550+/-56kPa in the intact joint and 195+/-145kPa following labrum resection. The trends observed in this experiment support the predictions of previous finite element analyses. Hydrostatic fluid pressurisation within the intra-articular space is greater with the labrum than without, which may enhance joint lubrication. Cartilage consolidation is quicker without the labrum than with, as the labrum adds an extra resistance to the flow path for interstitial fluid expression. However, both sealing mechanisms are dependent on the fit of the labrum against the femoral head.

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

[Early damage to the acetabular cartilage in slipped capital femoral epiphysis. Therapeutic consequences]

Epiphyseolysis capitis femoris represents the most common disorder of the adolescent hip, which is followed by a significant rate of early osteoarthrosis. Based on intraoperative findings during the surgical management of 23 hips with epiphyseolysis, early acetabular cartilage abrasion by a cam effect and acetabular rim impingement elicited by the prominent femoral metaphysis have been identified. Both phenomena cause direct damage to the hip joint, especially during flexion and flexion/internal rotation of the hip. As evidenced during surgery, the prominent and sometimes sharp-edged anterior neck metaphysis leveling or exceeding the femoral head showed marks of contusion and the labrum revealed erosions, scars, or tears. Moreover, adjacent acetabular cartilage damage was present ranging from superficial abrasions to a full thickness cartilage loss propagating into the weight-bearing area. In all patients the femoral head cartilage was intact; no avascular necrosis was present. These findings suggest that osteoarthrosis is triggered by direct mechanical damage in the epiphysiolysis hip already during the process of slipping and that chondrolysis appears to represent just the most severe form of this cartilage damage. Consequently, we propose that treatment should not only address the avoidance of a further slippage but also the prevention of impingement and cam leading to early acetabular cartilage damage.

[Retrospective analysis of healing problems after reamed and unreamed nailing of femoral shaft fractures]

168 fractures of the femoral shaft treated by intramedullary nailing were analyzed retrospectively. From 1986-1992 116 fractures had been treated with the reamed AO universal nail (RFN) and from 1993-1996 52 fractures with the AO unreamed femoral nail (UFN). In 24% of the RFN-group and in 2% of the UFN-group (p < 0.0001) open reduction of the fracture had been necessary. The time to radiological consolidation was similar in both groups (18.1 weeks +/- 6.1 vs. 18.3 weeks +/- 5.7, [mean +/- SD]). Delayed unions were less frequent in the RFN-group than in the UFN-group (3% vs. 13%, p = 0.01). Non-unions occurred in the RFN-group in 4%, in the UFN-group in 8%, the difference is not statistically significant (p = 0.46). Fractures with impaired consolidation (delayed-unions and non-unions) in the RFN group were distributed randomly along the femoral diaphysis, whereas all 11 fractures with retarded healing in the UFN group were short transverse or oblique fractures localized immediately distal to the femoral isthmus. We believe that there is mainly a mechanical reason for this phenomen, in addition to fracture type and fracture localization the (insufficient) length of the unreamed nails might have impaired stability further. The different factors should be investigated in larger series. As a consequence we now treat transverse and short oblique fractures of diaphyseal femoral fractures distal to the femoral isthmus with a RFN whereas in other types and localizations of diaphyseal femoral fractures we continue to use the UFN with special attention to maximal nail diameter and length.

Comparison of polyethylene wear with femoral heads of 22 mm and 32 mm. A prospective, randomised study

In this prospective, randomised study, we have compared the wear rate of cemented, acetabular polyethylene cups articulating with either a 22 mm or a 32 mm cobalt-chromium head. We evaluated 89 patients who had a total of 484 radiographs. The mean follow-up period was 71.4 months (SD 29.1). All the radiographs were digitised and electronically measured. The linear wear rate was significantly higher during the first two years and decreased after this period to a constant value. We suggest that this is partly due to a 'run-in' process caused by irregularities between surfaces of the cup and head and an initial plastic deformation of the polyethylene. The mean volumetric wear was 120.3 mm/year for the 32 mm head, which was significantly higher than the 41.5 mm3/year for the 22 mm heads. The mean linear wear rate was not significantly different. We were, however, unable to find radiological signs of osteolysis in the patients who had higher wear rates.

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.