Purpose of the study: Transposition of the anterior tibial tuberosisty (ATT) is often performed during the treatment of periodic dislocation of the patella. The purpose of this retrospective study was to evaluate the rate of medial femorotibial osteoarthritis and medial patellofemoral osteoarthritis after ATT transfer.

Material and method: We reviewed 129 knees in 106 patients who underwent surgery from 1988 to 2004. The patients were reviewed at mean 9 years follow-up, minimum 2 years. Three groups were defined:

isolated descent (n=15),

The degree of the medial shift and the descent depended on the distance from the tibial tuberosity to the trochlear notch and the Caton-Deschamps index measured preoperatively. Patients who underwent surgery for chronic anterior laxity and/or meniscal lesions were excluded (n=3). All patients were free of osteoarthritis before surgery. A complete radiographic series was available for 102 knees. Unilateral periodic dislocation of the patella was present in 60 patients whose knee x-rays were obtained bilaterally.

Results: All patients in group 2 were free of osteoarthritis. In group 2, the rate of medial femorotibial osteoarthritis was 10.5%; the rate of medial patellofemoral osteoarthritis was 21%. In group 3, the rate of medial femorotibial osteoarthritis was 7% and that of medial patellofemoral osteoarthritis 14%. For patients with unilateral periodic patellar dislocation, only the operated knees exhibited medial patellofemoral osteoarthritis (12%). The rate of medial patellofemoral osteoarthritis was significantly greater for knees with a medial shift of the ATT. The rate of medial femorotibial osteoarthritis was 6.8% for knees with medial shift versus 8.3% for the index knees. There was no significant difference between the medial shift knees and the index knees for medial femorotibial osteoarthritis.

Discussion: Biomechanical studies have shown increased stress forces on the medial compartment after medial shift of the ATT. However, these studies were performed with normal knees free of the morphological anomalies generally present in knees exhibiting periodic patellar dislocation (abnormally high tibial tuberosity femoral notch distance, trochlear dysplasia. In our series, regarding the rate of medial femorotibial osteoarthritis, there was no significant difference between the knees which underwent a medial shift of the ATT and healthy knees. Consequently, medial shift of the ATT should be avoided when unnecessary; the morphology of the trochlea (depth, morphology of the medial component) can induce increased medial stress on the patellofemoral joint.

It has been suggested that an increased posterior tibial slope (PTS) and a narrow notch width index (NWI) increase the risk of anterior cruciate ligament (ACL) injury. The aim of this study was to establish why there are conflicting reports on their significance. A total of fifty patients with a ruptured ACL and 50 patients with an intact ACL were included in the study. The group with ACL rupture had a statistically significantly increased PTS (p < 0.001) and a smaller NWI (p < 0.001) than the control group. When a high PTS and/or a narrow NWI were defined as risk factors for an ACL rupture, 80% of patients had at least one risk factor present; only 24% had both factors present. In both groups the PTS was negatively correlated to the NWI (correlation coefficient = -0.28, p = 0.0052). Using a univariate model, PTS and NWI appear to be correlated to rupture of the ACL. Using a logistic regression model, the PTS (p = 0.006) and the NWI (p < 0.0001) remain significant risk factors. From these results, either a steep PTS or a narrow NWI predisposes an individual to ACL injury. Future studies should consider these factors in combination rather than in isolation.

Purpose: The reputation of unicompartmental knee prostheses (UKP) has suffered from “errors of youth” but within the limits of the indication and with precise implantation, they have provided excellent results with miminal morbidity. We evaluated the five-year clinical and radiological outcomes with the Alpina-UNI prosthesis.

Material and methods: Fifty-eight Alpina-UNI prostheses (88% medial) were implanted in 1995 by two operators. Radiographic analysis was performed by an independent observer. The mean patient age at implantation was 72 years. Patients were evaluated at three months and one and five years. The Knee Society knee score as well as radiographic findings were noted. Indications were essential, traumatic, and necrotic non-displaced lateralised degeneration. Cemented implants were used for 92% of the knees. Results were analysed with SPSS software.

Results: At five years, 51 patients were reviewed, there were four deaths, one patient lost to follow-up and two early failures (secondary ACL tear, anterior descent of the tibial baseplate). Follow-up at 70 months was 95%. The KSS was significantly improved (+61%, p< 0.001) and remained stable during follow-up. Mean flexion at five years was 131°. Radiographic findings were satisfactory: no degradation of the contralateral compartment or the patellofemoral joint, no implant loosening or migration, no abnormal polyethylene wear. Stable lucent lines were observed for 17% of the implants, all measuring less than 1 mm. The mean tibial slope was 5°. There was no significant difference between the pre- and postoperative femoroatibial epiphyseal inclinations. The mechanical axis (HKA) was significantly improved (p< 0.001) and remained unchanged throughout follow-up, maintaining a 1°–5° undercorrection.

Discussion: The conclusions of the 1995 SOFCOT symposium emphasised the importance of indications and precise implant position for the prevention of early failure. The Alpina-UNI system has enabled reproducible accuracy for the femoral and tibial epiphyseal inclinations in the cuts allowing restoration of the initial anatomy, the correction of the HKA being explained solely by wear correction. This can explain the low rate of loosening and wear in this series. Unicompartmental replacement remains an excellent solution in the older patient due to the lesser morbidity. Mid-term results are encouraging. Further ten-year evaluation will provide information on implant longevity.

Purpose: We report a retrospective series of 98 consecutive total hip prostheses implanted without cement: the Aura stem and the Alizé cup coated with hydroxyapatite; reviewed at mean 9.6 years. The purpose of this analysis was to examine implant stability and wear.

Material and methods: Total hip prostheses implanted in 98 patients from January 1991 to January 1992 were reviewed: 60 women and 38 men, operated on by the same surgeon using an Alizé cup and an Aura stem without cement. Mean age at implantation was 66.5 years (30–85). Mean follow-up was 9.67 years. We retained 56 patients for this analysis (17 patients had died, 13 were lost to follow-up, 9 could not be followed, and 3 stem removals (3.1%)). This was the first procedure in all patients. Clinical outcome was assessed with the Postel-Merle-d’Aubigné (PMA) score and with a self-administered questionnaire. Radiologically, we assessed stability (tilt, implant displacement) and implant wear using MetrOs software data processing of digitalized radiograms. We also searched for qualitative radiographic signs of bone reaction to the implant.

Results: The overall PMA score improved from 11.96 preoperatively to 17.42 at the 5-year assessment and then fell to 15.67 at last follow-up. At five years 94% of the patients (92 hips) were satisfied and 98.3% (56 hips) were reviewed at 10 years. There were two fractures of the ceramic head after direct fall on the greater trochanter (requiring replacement of the femoral implant, the head and the polyethylene insert). There was one infra-prosthetic fracture which required stem replacement. Analysis of the radiograms did not demonstrate any abnormal ossification or lucency. MetrOs was used on 52 files: mean wear was 0.77 mm at 10 years (0.16–2.24 mm): wear and impaction (0.789 mm) of the stem were significantly correlated at 10 years while stem tilt was negligible.

Discussion: This radioclinical analysis demonstrated that these hydroxyapatite coated implants are stable over time. The clinical results are satisfactory with a small regression of the PMA score related to patient ageing. The radiographic measurements obtained with a precise rigorous tool were very encouraging. We compared our results with those of series using comparable implants.

Purpose: We report a retrospective continuous series of 107 total hip arthroplasties using a hydroxyapatite-coaated cup followed for a mean 9.67 years. We studied implant stability and component wear.

Material and methods: One hundred total hip arthroplasties were performed between January 1991 and January 1992. The series included 67 women and 40 men operated by the same surgeon who used the same Alizé cup and Aura cementless stem. Mean age at surgery was 66.5 years (range 30–85). Mean follow-up at review was 9.6 years. We retained 63 hips for analysis excluding 17 deaths, 16 patients lost to follow-up, 10 patients who could not be followed correctly, and only one implant ablation (0.9%). The implant was a first intention prosthesis in 90.7% of the cases and a second operation to replace a loosened primary prosthesis.

The Postel Merle d’Aubigné score was used to assess clinical outcome and all patients responded to a self administered questionnaire. Radiographically, we searched for signs of instability (tilt, displacement) and implant wear using precise digitalized measurements on successive digitalized x-rays with MetrOs software. We searched for qualitative radiological signs of bone reaction in contact with the implant.

Results: The overall PMA score improved from 10.63 preoperatively to 16.98 at the intermediary 5-year follow-up and was 15.77 at the 10-year follow-up. Satisfactory results were obtained in 93.9% of the patients at five years and 98.5% of the patients (64 hips) at 10 years. There were two fractures of the ceramic head after direct fall on the greater trochanter (requiring changing the femoral implant, the head and the polyethylene insert). There was one cup loosening at 9.5 years with verticalisation of the implant in an active athlete. Analysis of the x-rays did not demonstrate any abnormal condensation or lucent lines. Bony defects were observed in one case. The MetrOs radiographic data were available for 55 hips. At five years, mean wear was 0.53 mm, which increased to 0.76 mm at ten years (range 0.16 – 2.24 mm). Cup ascension was 0.15 mm at five years and 0.76 mm at 10 years. Mean cup tilt was 46.2° immediately after implantation and varied a mean 0.7° at five years and 1° at ten years.

Discussion and conclusion: This radioclinical study at ten years follow-up demonstrates that the hydroxyapa-tite surfaced Alizé implant is stable over time. The clinical results in this study were satisfactory with minimal regression of the PMA score related to patient ageing. The x-rays analysed with a rigorous and precise measurement instrument provided reassuring results. We discussed the one cup loosening and the clinical course of the two patients who underwent revision procedures after trauma-induced fracture of the ceramic head.