Purpose of the study: The objectives of this work were to assess the stability of outcome achieved after Duquennoy procedure to tighten the lateral capsule-ligament structures of the ankle joint. To do this, we reviewed the same series of patients at 3 and 25 years follow-up to analyse the very long-term stability, laxity, and stiffness of the ankle joint and any osteoarthritic degradation.

Material and methods: From 1975 to 1986, we performed 75 Duquennoy procedures on the lateral capsule and ligament structures of the ankle joint. At mean 25 years follow-up (2007) we were able to review 28 ankles (27 patients) with the same method as applied in 1980 (3 years follow-up). The function outcome was assessed with the Good, Karlsson, Duquennoy and Tegner scores. Clinically, other than joint range of motion, were noted varus laxity or anterior drawer. Static x-rays were obtained to search for signs of osteoarthritis and stress images to measure talocrural laxity, in comparison with the preoperative figures and the 1980 data.

Results: There were two early technique failures (one persistent talocrural instability, one subtalar instability). Good and Karlsson scores were good or excellent in 92% of cases. Patients were very satisfied with the operation and the VAS was 8.9/10. Pain and occasional instability were reported by 27% of patients. There was no talocrural no subtalar stiffness at last follow-up. Radiographic laxity declined significantly between the preoperative value and the last review. Only one patient presented a narrow talocrural space (less than 50% narrowing). Eight patients had osteophytes whose presence was not correlated with poor functional outcome. These osteophytes were also present on the controlateral side. Importantly, there was no significant difference in the mean function scores between 3 and 25 years follow-up (Duquennoy score). Similarly joint range of motion and radiographic laxity remained stable over time.

Discussion: The Duquennoy procedure to tighten the lateral capsule and ligament structures is a simple technique with rare complications which provides excellent results both in terms of ligament stability and in terms of preservation from degenerative osteoarthritis. These results remain stable over time. Conversely, the technique has no action on the subtalar joint and should not be proposed as treatment for associated subtalar laxity, if diagnosed.

Purpose of the study: Drilling along yields disappointing results for osteonecrosis of the femoral head due to the high failure rate despite prolonged rest and also because of the risk of fracture. To prevent these problems, we have developed a new drilling technique which was evaluated prospectively.

Material and methods: The procedure performed percutaneously uses a lateral cortical orifice measuring 5mm, non-concentrated autologous bone marrow was injected after drilling. Osteoinductive protein (BMP7) was associated in random fashion (groups BMP+ and BMP−). Ficat stage 1 and 2 necrosis was included. Outcome was the rate or revision for prosthesis.

Results: Forty hips (36 patients) were included and assessed at mean four years (range 2–6). The necrosis was related to: alcoholism (n=5), cortisone (n=25), barotraumas (n=2), metabolic disease (n=4), idiopathic condition (n=4). Group BMP- (drilling+bone marrow) included 24 hips and group BMP+ (drilling+bone marrow+BMP7) 16 hips. The groups were comparable regarding necrosis stage (15% stage 3, 65% stage 2, 20% stage 1) and mean Koo index (27 BMP+ vs 34 BMP-; NS). There were no infections and no fractures despite immediate and complete weight-bearing. The revision rate for prosthesis was higher in the BMP- group (67%) than in the BMP+ group (43%) but the difference did not reach significance (p=0.10). The failure rate was not affected by the severity of the necrosis in the BMP+ group: all stage 3 hips were revised in the BMP- group versus none in the BMP+ group. The only variable predictive of revision for prosthesis was the Koo index (p=0.02).

Discussion: Adjunction of BMP did not improve significantly the success rate of drilling with bone marrow adjunction but adding BMP appeared to limit the unfavourable impact of server necrosis observed in the BMP- group. To reach a statistical power of 80%, 40 cases would be needed in each arm. This threshold has not yet been reached. It can be noted however that the proposed method does ensures early weight bearing without the risk of complications. Similarly, since it is a percutaneous procedure, later arthroplasty is not compromised. The principle confounding factor, the richness of the bone marrow, was not assessed, motivating a new randomized trial with measurement of CFU-F.

Purpose of the study: Two principle angles describe the orientation of the acetabular reconstruction of hip arthroplsty: lateral inclination and anteversion. Lateal inclination is easily determined on the plain x-ray but the measurement of anteversion generally requires axial computed tomography (CT). The values measured for acetabular anteversion depend on the planes chosen as reference. Similarly the measurement of acetabular inclination using conventional radiographs is often considered imprecise due to the large number of variables involved. Several reference planes are described in the literature. The purpose of this work was to characterise the values obtained using two reference planes, the anterior pelvic plan (APP) used for navigation and the pelvic axis (proposed by other authors).

Materials and Methods: We used the Hip-Plane-Sympios^® software to determine lateral inclination and anteversions using each reference plane. The APP was defined by three points: the anterosuperior border of the pubic symphysis, the anterior border of the two antero-superior iliac spines. The pelvic axis was defined by three points: the centre of the S1 plateau and the centres of the two femoral heads. A control reference plane (the plane of the CT table which corresponds to the conventional radiographic plane) was also used. Seventy-six patients scheduled for total hip arthroplasty for osteoarthritis were included in this protocol.

Results: Values measured for the APP were: mean acetabular inclination 52.5°± 4.1° (40–62°), mean acetabular anteversion 24.1°±5.8° (14–35°). Values measured for the pelvic axis were: mean acetabular inclination 47.6°± 4.5° (37–59°), mean acetabular anteversion 12.9°±7° (2–31°). In the plane of the CT table: mean acetabular inclination was 50.6°±4.2° (38–57°) and mean acetabular anteversion 20.2°±702° (1–40°). All of these values were significantly different from the others (p< 0.001). Use of the APP yields values higher than conventional values and those obtained using the pelvic axis, yet the distributions remained identical.

Discussion: The APP is used for total hip arthroplasty navigation systems. It is important to recognised that the angles measured in reference to this plane are greater than the classical radiographic values measured for acetabular inclination. The pelvic plane produces angles closer to the generally accepted anatomic values. Angles measured relative to the radiographic table are intermediary.

Purpose of the study: Most systems used for computer-assisted total hip arthroplasty require preparatory computed tomography acquisition or use of multiple bone markers fixed on the pelvis. In order to overcome these problems, we developed a novel system for CT-free computer assisted hip surgery based on a functional approach to the hip joint. The concept is to orient the cup within a cone describing hip motion. The purpose of the present study was to analyze preliminary results obtained with this new system.

Material and methods: This new system was used to implant 18 primary total hip arthroplasties in 16 women and 2 men (mean age 68±7.8 years, age range 54–83 years) with degenerative disease. Two optoelectronic captors were fixed percutaneously on the pelvis and the distal femur. The acetabulum was reamed, then the femur prepared with instruments of increasing caliber. The last reamer positioned in the shaft carried an upper head which matched the size of the prepared acetabulum. Hip joint motion was recorded to determine the cone of maximal hip mobility. The system then oriented the cup so that this cone was completely included the cone described by the prosthesis.

Results: There was one traumatic posterior dislocation (fall in stairs) at three weeks, without recurrence. The Postel Merle d’Aubigné score improved from 8±2.9 (3–12) preoperatively to 17±0.8 (16–18) at last follow-up. None of the patients complained about the sites where the percutaneous markers were inserted and ther were no cases of hematoma or fracture. Mean leg length discrepancy was 5.6±7.5 mm (range 0–25 mm) before surgery and 0.6±3 mm (range −5 to 10 mm) at last follow-up. Mean anteversion of the femoral implant was 22.3±6.7° (14–31). Anatomic anteversion of the cup (measured from a marker linked to the pelvis and thus independently of the position of the pelvis) was 25.9±10.4° (12–40). The sum of the femoral and acetabular anteversions was 48.2±14.6° (range 27–71°).

Conclusion: This method can be used in routine practice without lengthening operative time excessively. It provides a safe way to control the length of the limb and helps position the cup. This study demonstrated that there is no ideal position for the cup that can be applied for all patients. Because of the wide spread of the inclination and anteversion figures, half of the cases were outside the safety range recommended by Lewinnek.

Purpose of the study: To compare the DHS plate fixation with the Targon PF nail for the treatment of intratro-chanteric fractures.

Material and methods: This was a prospective randomized study including 60 patients hospitalized in the emergency setting between December 2003 and June 2004for intratrochanteric fractures. The AO classification was used. We analyzed: patient status (ASA), operative time (type of implant, duration), the postoperative period (blood loss, radiologic findings, duration of hospital stay, early postoperative complications) and at last follow-up, Harris hip score, date of resumed walking, mortality. Patients were assessed at three months postop. This study included 60 patients, 34 with a Targon PF nail and 26 with a DHS. Mean patient age for nailing was 81 years (SD 12.8, range 23–86); for DHS it was 82 years (SD 9.8; range 47–97).

Results: Mean blood loss was 410 ml with the Targon PF nail and 325 ml with the DHS, a nearly significant difference (p=0.07). The other results did not demonstrate any significant difference. At three months five cases of screw cut out were noted. Bone healing was achieved in all cases. The Trargon PF nail and the DHS provide equivalent results, with less bleeding an lesser cost for the DHS.

Purpose of the study: Reconstruction of the anterior cruciate ligament (ACL) has become a common procedure. We compared two randomized series: intra-articular (Kenneth-Jones) versus intra- and extra-articular (MacInJones).

Material and methods: From January 1995 through March 1998, 73 knees were treated surgically for differential medial laxity measured at 7 to 12 mm on passive stress x-rays in 20° flexion. Group 1 (ACL reconstruction alone) included 34 patients (aged 27.1±7.5 years). Group 2 (ACL reconstruction plus extra-articular plasty) included 29 patients (aged 28.5±12 years). Function was scored 72% in group 1 and 68% in group 2 at mean seven years follow-up (102 and 93 months follow-up respectively). Anterior laxity was measured radiographically and with KT-1000 and the position of the tunnels was assessed according to Aglietti.

Results: According to the IKDC, functional outcome was 83.9±3.1 in group 1 and 83.3±3.6 in group 2. The overall IKDC classification was 0A, 57.8% B, 26.3% C, and 15.7% D for group 1 and 58% A, 52.9% B, 29.4% C, and 11.7% D for group 2. The pivot-shift test was negative in 61.1% of group 1 knees (27.7% grade 1 and 11.1% grade 2) and negative in 83.3% of group 2 knees (16.6% grade 1). In group 1, the radiological drawer showed 46.09% improvement in the differential laxity for the medial compartment and 41% for lateral compartment. In group 2 the corresponding improvements were 44.8% and 44.6%. There was no difference in tunnel position between the two groups.

Discussion: The two-year results of this series did not provide any evidence favoring a clear advantage of complementary lateral plasty. At seven years follow-up, the pivot-shift test appeared to favor associated lateral plasty (p=0.09), but with no significant difference in laxity for the two compartments.

Conclusion: Anterior laxity was only incompletely controlled by both reconstruction techniques. In this context of relatively limited laxity (7–12 mm initially), at seven years follow-up there was no certain advantage of complementary lateral extra-articular plasty in combination with ACL reconstruction.

Purpose: In young active subjects, total hip arthroplasty (THA) raises the risk of early polyethylene wear eventually warranting the use of alternative bearings. The purpose of this study was to analyze outcome in subjects aged less than 50 years implanted with a primary metal-on-metal prosthesis.

Material and methods: Between 1995 and 1998, thirty-nine THA with a metal-on-metal bearing were implanted without cement in 30 consecutive patients aged less than 50 years, mean age 23–50). There were nine bilateral implantations. The cementless implants had surface treatment without hydroxyapatite and 28 mm heads. The indication for THA was necrosis in twenty cases, osteoarthritis in nineteen, most in patients with hip dysplasia. The Devane classification placed 84% of the patients in levels 4 or 5, indicating heavy work and/or sports activities. Inclusion criteria were: 1) age less than 50 years, 2) significant activity (occupation and/or sports), 3) osteoarthritis or necrosis. Patients were included and followed prospectively. Serum cobalt level was measured at last follow-up. None of the patients were lost to follow-up.

Results: The Postel-Merle-d’Aubigné score (PMA) improved from 12.8±2.2 (7–15) before surgery to 17.2±1 (14–18) at 5.1 years (5–6.3). None of the patients complained of hip pain. Two patients has moderate inguinal pain related to a cupiliopsoas conflict. All patients achieved complete weight bearing on the fourth postoperative day excepting three who resumed weight bearing at six weeks due to an acetabular augmentation graft. There were no cases of implant migration and all implants exhibited signs of osteointegration on the radiograms. There were no postoperative dislocations and no cases of osteolysis could be identified, particularly in the eight patients who had increased serum cobalt (four bilateral implants) and who had no other statistically significant favouring factor.

Conclusion: The results at five years suggest that the second-generation metal-on-metal bearing is a reliable alternative when THA is proposed for young active subjects. Long-term follow-up of this cohort of subjects at high risk of wear is necessary to confirm these encouraging results.

Purpose: Arthodesis is the conventional treatment for the rheumatoid wrist. In the event of severe bilateral disease, bilateral arthrodesis can be discussed as an alternative to unilateral arthrodesis an contralateral prosthesis. We wanted to know the functional outcomes after bilateral arthrodesis.

Material and methods: This retrospective analysis involved seven patients (one man and six women), mean age 46 years (28–69) who underwent total bilateral arthrodesis of the wrist for inflammatory joint disease (six rheumatoid, one chronic juvenile arthritis). Mean follow-up was five years. The patients were reviewed clinically and radiographically. We noted goniometric measurements of the upper limbs, the Jebsen hand function test (for activities of daily life), force (wrist and grip), and the Buck-Gramcko-Lohmann evaluation.

Results: On average, the position achieved after arthrodesis was 2° flexion (−5° to +10°) with 6° ulnar inclination (−5° to +20°). Radiological fusion was achieved in all cases. At last follow-up, we noted that three patients had resumed their occupational activities, one had been reclassified as handicapped, and one as disabled. One patient was a housewife and one other woman was retired. The Jebsen hand test showed that our patients could perform 32 of the 49 daily activities (65%). Daily activity was noted excellent in three patients, good in two and fair in two. The Buck-Gramcko-Lohmann score was fair 6.8/10 (2–10) corresponding to good outcome. All patients were satisfied with the outcome.

Discussion: Daily life activities could be performed readily after bilateral arthrodesis of the wrist. Perineal hygiene was possible for five of our patients. The only problems concerned activities requiring force and fine movements, because of the apprehension and the lack of fine dexterity. Poor results could be attributed to metacarpophalangeal deformations and decreased grip force. We observed an 80% reduction in force compared with a representative population of non-operated patients with rheumatoid disease. Bilateral arthrodesis is a valid alternative to bilateral arthroplasty or combined arthrodesis prosthesis implantation. It does not expose the patients to the risk of mechanical arthroplasty.

Purpose: Femoral revision can be difficult when associated with important loss of bone stock and femoral deformation, particularly when the deformation prevents using a long prosthesis despite major loss where it would be useful. We describe a novel technique allowing a simultaneous solution to these two problems and report preliminary results in five patients.

Material and methods: The technique was applied in five patients. Briefly, one or several osteotomies at different levels were performed to correct the deformation in one or more planes, and fixed with a locked femoral implant. Femorotomy was associated in four patients to facilitate removal of prior implants and constituted one of the correction osteotomies. In one patient, non-union of the greater trochanter was treated with a plated autograft. The series included three men and one woman, mean age 72 years (65–83). According to the SOFCOT score, femoral bone loss was grade II in four patients and grade III in one. All femurs had varus deformation (mean 21°, range 16°–40°), and two femurs exhibited permanent flexion (40° and 45°). One shaft osteotomy was used in four patients and two osteotomies in one. The locked femoral implant measured 250 mm in three and 300 mm in two.

Results: Mean follow-up was 3.5 years (0.5–5). One patient committed suicide at six months. The mean Postel Merle d’Aubigné score improved from 9.4 (7–11) to 16.4 (15–18). The trochanter non-union and all osteotomies head at three to four months except one case of shaft non-union which was well tolerated (PMA=16, in a patient without femorotomy who did not require recalibration of the proximal femur). In these healed cases, remodelling and/or spontaneous reconstruction of the femur was observed without grafting for the shaft. There was no stress shielding aspect in the patients with the longest follow-up although they had non-cemented stems with distal locking and no surface treatment.

Conclusion: The technique proposed for this specific indication enables resolution of the double problem of fixation and correction of deformation while allowing spontaneous reconstruction around the non-cemented locked implant. Use of femorotomy is recommended to allow recalibration and stabilisation of the proximal femur around the stem. Longer follow-up is needed to ascertain longevity of the spontaneous reconstruction. Nevertheless, these non-reintegrated implants behave like locked centromedullary nailing.

Aims: The goal was to determine if young patients respect the instructions for medical supervision control instructions after a total hip arthroplasty (THA). Methods:We performed 50 THA (Harris cups and ABG I stems) in 39 patients, mean age 38 years ± 11 (15–58). There were thirty-eight 28mm femoral heads (30 zirconia, 8 chromium-cobalt) and 12 chromium-cobalt heads in 22mm. Each patient was told how necessary a regular medical supervision was with the following schedule: controls at 2 months, 1 year then every two years. In 2000, all the patients were evaluated (no lost for follow-up). Wear was measured according to Livermore with a digitizer. Results: At 72 ± 14 months of follow-up (5–9 years), 51% of the patients (20/39) did not come back for the intermediate controls. No factor could be accounted for that, except being a male (p=0.04). Wear was rather severe (average 0.23 mm/year). 37% of the patients with a severe wear (> 0.2 mm/year) did not come back for intermediate controls and were all free of symptoms. There were 3 revisions because of wear (> 2 mm) and 3 others hips are awaiting revision because of wear. Three of these 6 patients did not come back for intermediate examination. The 28mm heads induced more wear than the 22mm heads (p=0.008). No other factor was related to how severe wear was (age, sex, activity or thickness of polyethylene inserts). Moreover the zirconia did not reduce wear. Conclusion: In spite of the recommendations, half of the patients did not respect the medical supervision schedule and that was unpredictable. We recommend a careful follow-up of young patients after a THA in order to detect wear (usually free of symptoms). Moreover our study underlined that the zirconia wasn’t so efficient to prevent wear phenomena.

Purpose: Crush injury of the upper limb often causes bone and soft tissue damage leading to a paralytic hand. We report our experience with reactivating wrist and finger flexion using a neurotised latissimus dorsi transfer in patients with volkmann syndromes of the forearm.

Material and methods: Mean patient age was 25 years and mean follow-up was three years. The surgical procedure consisted in a free latissimus dorsi flap with arterial suture onto the ulnar artery and neurotisation using the largest median nerve branch innervating the finger flexors. The muscle was fixed proximally on the medial epicondyle; the distal fibrous lamina was divided for suture to the deep flexor tendons. Mobilisation started 21 days after surgery.

Results: The four-month electromyogram demonstrated reinnervation of the latissimus dorsi. The patient recovered thumb-index opposition with flexion of the long fingers enabling daily life activities. All patients required occupational reclassification but stated they were satisfied with the operation. Flexion of the fingers and wrist was active and was not obtained by tenodesis.

Discussion and conclusion: Volkmann syndrome leaves serious sequelae after crush injury to the forearm. The usual surgical techniques enable reduction of claw fingers by distention but do not, due to muscle necrosis, enable proper function. The free latissimus dorsi transfer method improves trophicity of the forearm and, by neurotisation, enables active hand flexion. Because the nervous pedicle of the flap is short, recovery is rapid, avoiding degeneration of the transferred muscle.

Purpose: Posterior stabilisation with a third condyle was introduced by Henri Dejour with the HLSI prosthesis. While the posterior stabilisation process has been validated, this implant still raises some problems with the tibial fixation in patients with advanced joint degeneration, leading to the development of the HLSII model. The purpose of the present retrospective work was to evaluate functional outcome and persistance of the HLSII prosthesis fixation.

Material and methods: Between January 1992 and December 1993, 105 total knee arthroplasties (TKA) were performed in 94 consecutive patients using posterior stabilised HLSII prostheses. Indications were joint degeneration (40% stage 4) in 78% and polyarthritis in 19%. None of the patients were lost to follow-up but 14 patients died, six were bedridden (stroke sequela) and four were contacted by phone only. In all, 70 patients (77 TKA), mean age 66 years (22–79) were retained for clinical and radiological assessment at mean follow-up of seven years (range 6–8 years). All implants were cemented and the patella was resurfaced in all cases. Eight operators participated in this series. Junior surgeons (n=5) implanted one-third of the prostheses.

Results: The mean IKS knee score rose from 27±18 points (0–63) preoperatively to 81±18 (21–100) at last follow-up, function score from 35±20 (0–75) to 64±24 (0–100) (P< 0.0001). Motion changed from 114° (60–140°) to 116° (40–135°) (NS).Eighty-six percent of the patients used stairs (13% without handrail and 28% with alternate steps) versus 52% before the intervention (1% without handrail and 1% with alternate steps). (P=0.001). Knee alignment was normal ±5° in 87% of the cases versus 27% before surgery (P< 0.0001). Seventy-nine percent of the knees had a slope ±2° (desired slope 0°). The patellar retinaculum was sectioned in one quarter of the knees which led to four of the five postoperative haematomas (no revision). Five patellar fractures were noted, including two with patellar loosening (revised) and one clunk (cured after arthroscopic release). Lucent lines observed under the medial tibial plateau in 30% of the cases (all < 1 mm) were more frequent in patients with more severe joint degeneration and genu varus preoperatively (P =0.01). There was no case of aseptic femorotibial loosening. One case of late infection (30 months) was followed by replacement arthroplasty. Survival rate, taking mechanical and/or infectious failure as the endpoint, was 97± 1.3% at 90 months.

Discussion: Good axial control emphasises the reliability of the instrumentation since one-third of the prostheses were implanted by junior surgeons. Improvements in tibial fixation with the HLSII appear to be effective, particularly for stage 4 degeneration. Long-term surveillance is however necessary. The femoropatellar joint can give rise to non-infectious complications and should be improved. The concept of posterior stabilisation with a third condyle authorises good flexion amplitude and favours use of stairs.

Purpose: The purpose of this prospective work was to determine: 1) the frequency of iliopsoas conflicts with prosthetic acetabular material in patients with a painful total hip arthroplasty, and 2) to determine the diagnostic features of this conflict and the results of an adapted therapeutic approach.

Material and methods: This prospective study was conducted between 1988 and 2000 in 206 painful total hip arthroplasties. Nine patients (4.%), mean age 50 years (38–65) had a highly suggestive clinical presentation (eight press-fit cups without cement, one metal-backed cemented cup). Mean delay to onset after implantation of the total hip arthroplasty was 7.3 months (1–48). The predominant clinical sign was groin pain triggered by active flexion of the hip with pain from 3° to 70°. For these nine patients, there was no sign of loosening and puncture had ruled out infection. The diagnosis was confirmed by sedation of the pain after extra-articular infiltration in contact with the anterior acetabular rim (rim overhang in six out of nine cases) under computed tomographic guidance.

Results: Therapeutic infiltration (xylocaine-slow release corticosteroids) under computed tomographic guidance provided complete sedation in four out of nine cases and partial sedation in one. Four patients experienced recurrence leading to terminal tenotomy of the iliopsoas which provided complete sedation in three and partial sedation in one. In all, seven of the nine patients achieved complete pain relief (four after infiltration including one recurrent case, and three after tenotomy). Physical examination at last follow-up did not disclose any loss of flexion amplitude of the thigh.

Discussion and conclusion: The delay to symptom onset was variable, but a symptom-free interval was always observed after implantation of the total hip arthroplasty. An anatomic factor (anterior cup rim) was not indispensable for diagnosis as it was confirmed in one of three cases with a positive infiltration test without rim overhang. The infiltration test was essential to confirm diagnosis and constituted the first therapeutic attempt which allowed complete cure in four of the nine patients. Tenotomy, indicated in case of recurrence, achieved complete cure in three of the four cases. The cup does not have to be changed necessarily to treat iliopsoas conflicts since infiltration or simple tenotomy provided complete cure in seven out of nine cases.

Purpose: Changes in the lever arm of the abductors is not always perfectly controlled during implantation of total hip arthroplasties. Its possible effect on the development of prothesis dislocation is not known. The purpose of this study was to evaluate the influence of the lever arm and its modifications on the development of prosthetic instability.

Material and methods: We analysed prospectively 73 total hip arthroplasties implanted via the posterolateral approach. The study group was composed of a consecutive series of 45 dislocated prostheses and a control group of 28 stable prostheses selected at random. The following measurements were made on the anteroposterior x-ray: 1) lever arm of the abductors, 2) femoral offset. These measures were compared with the healthy contralateral hip and when this hip was diseased or had a prosthesis, with the pre-implantation x-rays.

Results: None of the studied parameters was statistically different between the dislocated and stable prostheses. However, in the dislocated prostheses, the lever arm of the abductors before insertion of the prosthesis was shorter than in the control group (p = 0.04) suggesting the presence of a group of hips “at risk”. There was a correlation between the offset values and the lever arm values for the stable prostheses and for the healthy contralateral hips in both groups. Conversely, this balance was not found in the dislocated hips. The lever arm/offset ratio was calculated to determine if the ideal ratio influenced hip stability. This ratio was not directly related to the development of dislocation, but it was decreased for dislocated hips. This ratio was ideal for 75% of the stable prostheses and for only 53% of the dislocated prostheses.

Conclusions: We concluded that: 1) hips “at risk” of dislocation would have a shorter lever arm, 2) the lever arm or the femoral offset do not have a direct effect on dislocation, and 3) stable hip prostheses have a balance similar to that in healthy hips identified by a correlation between the lever arm and the femoral offset. We thus emphasise the importance of respecting these parameters although they are probably not the only factors influencing prosthesis stability. Allowable variations are small, demanding careful and precise operation planning.

Purpose: The aim of this study was to follow a prospective cohort of young subjects with total hip arthroplasties (THA) in order to determine 1) how they complied with instructions concerning the surveillance of their implant, and 2) determine factors affecting non-compliance and the potential consequences in terms of wear.

Material and methods: We implanted fifty Harris I cups with the ABG I stem in 15 young men and 24 young women (11 bilateral implantations) between 1991 and 1995. These patients were a non-consecutive prospective series of patients under 60 years of age (mean age at implantation was 38 ± 11 years, range 15–58 years). The ABG I stem was implanted when the femoral canal was cylindrical, other implants were chosen for other morphologies. 28-mm femoral heads were used in 38 cases (30 zircone, 8 chromium-cobalt, polyethylene thickness 8.6 mm, range 8.3–12.4). The patients were informed of the need for regular surveillance with controls at two months, and one year and then every two years. We re-evaluated all the patients again in 2000. Radiographic wear was assessed according to Livermore using a numeric table (OrthoGraphics).

Results: At mean follow-up of 72 ± 14 months (5–9 years), 20 of the 39 patients (25/50 implants) had not attended the intermediary consultations, but all were seen again for the systematic review made in 2000. There was no particular factor related to non-attendance other than male gender (p = 0.04). Wear was rather severe. Mean values were: linear wear 1.32 mm, 0.23 mm/an. Thirty-seven percent of the patients who had severe annual linear wear (> 0.2 mm) had not attended consultations, all were asymptomatic. The 28 mm head produced more volumetric wear than the 22 mm heads (p = 0.008). There was no other factor correlated with severity of wear (age, sex, activity, polyethylene thickness). This systematic revision led to: three replacements due to excessive wear > 2 mm and replacements planned for three others with > 2 mm wear. These six patients were asymptomatic and three of the six had never attended the planned visits.

Conclusion: Despite our recommendations, half of the patients did not comply with the planned surveillance protocol. Non-compliance being inevitable, we recommend regular systematic recalls to detect severe wear early, even in asymptomatic patients. In addition, our study demonstrated that zircone heads contribute little and confirmed the interest of 22 mm heads to limit wear phenomena.