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Femoroacetabular impingement (FAI), a recently proposed mechanical concept regarding the development of osteoarthritis (OA) of the hip, is gaining increased acceptance. Both osseous deformity and use of the hip may result in hip damage. Osseous deformities are seen on the acetabular (pincer) or the femoral (cam) side of the hip, leading to characteristic alterations of the acetabular rim. Cam FAI is found in 20-30-year-old athletic men, revealing deep cartilage avulsions from the acetabular rim while the labrum is frequently intact. In pincer FAI, found in 30-40-year-old women, the labrum is frequently significantly destroyed with only minor damage to the acetabular rim. Professional or athletic impact activities can trigger even mild FAI deformities to become symptomatic. For some FAI deformities, the etiologies are known, but for most of them the exact causes are unknown. An improved understanding of the etiology of FAI and its role in the development of hip OA might lead to a reduction in the prevalence of so-called primary OA of the hip.

After disastrous outcomes due to wear-induced osteolysis in the 1980s, hip resurfacing arthroplasty has undergone a renaissance, mainly because of the introduction of metal-on-metal bearings. However, there are still problems associated with this technique, such as femoral neck fractures, neck thinning, and aseptic loosening, and their causes are still being investigated. During the last years, increasing evidence has shown that both the frequently used posterior approach to the hip as well as preparation of the femoral epiphysis can impair blood supply to the femoral head. In the presence of mechanical stresses (impaction, heat development during cement polymerization) during the implantation, the epiphysis might not be able to compensate for this. This paper summarizes the current understanding of the blood supply to the femoral head and proposes a way to preserve the viability after hip resurfacing.

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.

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.

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.

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.

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.

We evaluated the radiological pelvic diameter after the bernese periacetabular osteotomy (PAO) and its influence on the modality of birth. Out of 93 woman, 17 had a total of 28 babies after PAO; 18 children were delivered spontaneously and 10 by caesarean section. The rate of section (36 %) was twice as high after PAO as in a normal population. In 50 % the indication to perform a section was made because the obstetrician anticipated problems during delivering after PAO. The average weight of birth was 3348 g +/- 285 g in the spontaneous delivery group, 3475 g +/- 356 g in the section group. The weight of birth didn't correlate neither with the duration of delivery nor with the indication to perform a section. The 17 woman who had a baby after PAO didn't show a significant change of the radiological diameters of the pelvis: pelvic entrance (before PAO 15. 4 cm, after PAO 15.7 cm), mid-pelvis (before PAO 11.8 cm, after PAO 11.8 cm) and pelvic outlet (before PAO 14.2 cm, after PAO 13.7 cm). We found that the PAO does not influence the anatomical diameters of the birth canal and therefore is not an indication for a section.

The periacetabular osteotomy is a strategy for the treatment of residual hip dysplasia in young adults with the aim of preventing secondary coxarthrosis. This polygonal, juxta-articular osteotomy respects the vascular blood supply to the acetabular fragment and thus facilitates an extensive acetabular reorientation with improvement of the insufficient coverage of the femoral head, including medial displacement of the fragment. All osteotomies are performed by one approach, the modified Smith-Petersen, which allows an anterior capsulotomy. Inspection of the joint not only provides information on acetabular rim pathologies, but also facilitates the control of 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. The dimensions of the true pelvis are unchanged, providing the capacity to have an unimpeded delivery in women. This paper describes the preoperative evaluation, current indications, surgical technique, postoperative care, and the results of this osteotomy.

The authors present a new technique for fusion of the hip joint through an anterior approach (Smith-Petersen) with the use of a ventral plate and a lateral compression screw. The indications for fusion of the hip joint are discussed and some cases are presented. The advantages of this technique are that strong bone stock for fixation is used on the pelvic side, that the abductor muscles and vascularization of the femoral head are left intact, and that no external fixation (cast) is routinely used for after-treatment.

The antishock pelvic clamp provides direct reduction and compression of unstable posterior pelvic ring disruptions. This is effective in preventing excessive blood loss, which is common in these fractures. Comparable to a carpenter's C-clamp, this device is applied in less than 10 min and exerts transverse compression directly over the iliosacral region, reducing the displaced sacral fractures or SI joint diastasis. Early reduction closes the bleeding surfaces and restores the intrapelvic space, providing for earlier tamponade, further decreasing blood loss. The clamp does not interfere with a possible subsequent laparotomy or necessary diagnostic procedures. On 10 cadaveric pelvic specimens the bone yield under compression with the pelvic clamp ranged from 135 N to 685 N relative to the mechanical quality of the bone. This is sufficient to stabilize the posterior ring during further manipulation of the patient in the early phase. Details of the application technique and our clinical experience with the pelvic clamp in the first 17 patients are discussed.

Fractures of the hip and pelvis are rare in the growing skeleton. Conversely, they are complicated by morphological and functional abnormalities in a particularly high percentage of cases. We present a review of posttraumatic structural abnormalities and their consequences. In addition to the common presentations, less well-known abnormalities and their possible treatments are discussed.

Severe post-traumatic deformities of the hip are most often treated by total joint replacement. However, in certain circumstances a joint-preserving approach is appropriate, especially in younger patients. There is minimal literature on this topic and the cases reported are few in number. In this paper we describe our experience with afflictions of the acetabulum, proximal femur and juxta-articular soft tissues where conservative procedures may best be employed. We include some new entities and their treatment options.

Osteotomy and revascularization have both been used for many years in the therapy of partial aseptic necrosis of the femoral head in the adult. We first attempted a combination of the two techniques in 1978. Stress on the necrotic sector was relieved by intertrochanteric osteotomy, and the necrotic part of the bone was revascularized with a pedicled iliac crest bone graft based on the deep circumflex iliac vessels. Long-term results are now available in 45 hips in 38 patients, with a mean follow-up time of 32 months. Clinically, 71% of the hips were rated very good or good, and among those classed as stage II before surgery the results were rated as very good or good in as many as 90%. Subjective evaluation of the hips by the patients confirmed these results: 85% of the hips were judged to be optimal or markedly improved compared with before operation. Radiological evaluation showed further flattening of the femoral head in one case. A segmental collapse of the femoral head, i.e. stage III lesion according to Ficat, occurred in 2 hips with stage II preoperatively. In 6 hips with stage III necrosis preoperatively secondary arthritis developed. Computerized tomograms taken of all 25 hips from which metal implants had been removed showed signs of integration of the graft in 68%. Scintigraphy with 99-Tc-diphosphonate showed a homogeneous uptake in 42.8% and a non-homogeneous uptake in the remaining 57.2% of the cases. So-called photopenia was not observed in any of the hip joints treated.(ABSTRACT TRUNCATED AT 250 WORDS)

Soft tissue tumors of the extremities require a definitive histopathological diagnosis and adequate treatment unless they are known to have been present for years without any clinical change. For lesions with a straightforward clinical diagnosis (ganglion of the wrist) and for superficial tumors smaller than 3 cm, excisional biopsy is adequate. For all other lesions an open incisional biopsy should be performed. If the lesion is potentially malignant, all the appropriate staging studies must be performed before biopsy; if the tumor has been biopsied without prior staging and unexpectedly reveals a malignant lesion, complete staging must be performed before definitive surgery is undertaken. Soft tissue sarcomas extend rapidly within the tissue of the compartment they originated in, but tend to respect compartmental boundaries. Radical resection of the entire compartment containing the sarcoma is thus the surgical treatment of choice. Adjuvant radio- and/or chemotherapy are necessary in the majority of these cases and should be integrated into the treatment strategy.

The Müller acetabular reinforcement ring has proven very useful, especially in total hip revision when the bone of the acetabulum is of poor quality or deficient. However, the acetabular reinforcement ring may also be indicated in primary total hip replacement, especially in the case of poor quality bone in the acetabular bone stock, e.g. in chronic polyarthritis or protrusio acetabuli, or of deficient morphology of the acetabulum, e.g. in hip dysplasia. We analysed the results recorded in 145 patients operated on between 1977 and April 1983. Each of these patients had received a total hip prosthesis for the first time, with the polyethylene cup supplemented by an acetabular reinforcement ring. This patient group cannot be compared with the usual patient populations reported on in connection with primary hip replacement, since most of our 145 patients had several risk factors and had undergone previous surgery on up to seven occasions on the hip ultimately replaced by a prosthesis. Radiological analysis did not show a significant correlation between malposition of the acetabular reinforcement ring and signs of loosening, except when the acetabular component had been implanted in a most atypical manner. The infection rate was 4.8%, but it must be borne in mind that from 1977 to 1983 there was no routine prophylaxis with antibiotics. The incidence of aseptic loosening of the acetabular reinforcement ring necessitating revision was 0.7% after a mean follow-up of 7.7 years (range 5.5-11 years).(ABSTRACT TRUNCATED AT 250 WORDS)

Severe bone deficiency in total hip arthroplasty (THA) represents a serious problem, and there is an increasing demand for reconstructive measurements even on the femoral side to salvage these hips. The different therapeutical concepts are reviewed. Mechanical stability has proved to be of the utmost importance for successful results; fixation of the prosthesis by acrylic cement both in the graft and in the host femur seems to be superior to cementless fixation in most cases. The Wagner cementless self-locking revision stem has the advantage of facilitating regeneration in the deficient proximal femur without allografts and their disadvantages.

This report documents our limited experience with total hip replacement requiring large bone-graft reconstruction of the acetabulum with internal fixation. Four of the 14 patients were elderly and had a fresh fracture of the acetabulum; 6 had severe loosening of the acetabular companent with non-union, necessitating plate fixation along the pelvic rim in 5 patients. Four patients had large defects after tumor resection. In only 1 of these 14 cases did loosening occur. Our results are promising and we plan to increase the use of pelvic plates in these extremely unstable cases. Following stabilization of the pelvic ring, a metallic reinforcement ring increases stability. These operations were performed via an anterior ilioinguinal approach.