Introduction

In valgus knees, ligament balance remain difficult when implanting a total knee arthroplasty (TKA), this leads some authors to systematically propose the use of constrained devices. Others prefer reserving higher constraints to cases where it is not possible to obtain final satisfactory balance: less than 5 of residual frontal laxity in extension in each compartment, and a tibiofemoral gap difference not in excess to 3mm between flexion and extension. The goal of the study was to assess if is possible to establish preoperative criteria that can predict a constrained design prosthetic implantation at surgery.

Purpose of the study: The favourable outcome with knee arthroplasty can be compromised by persistent unexplained pain. Postoperative pain accounts for about 30% of the complaints of chronic pain present in 25% of the general population and would be to a large extent of neuropathic origin (DCN). The purpose of this work was to evaluate pain before and after knee arthroplasty in terms of intensity and clinical expression.

Material and methods: A prospective monocentric epidemiology study was conducted to validate self-administrated questionnaires which, over a six month period, were completed by knee arthroplasty patients. A numerical scale (Nu) from 0 to 10, a 7-item questionnaire screening for neuropathic pain (burns, painful cold, electrical discharge, tingling, pins and needles, numbness, itching) scored 0 or 1 and positive if the score is ≥3 (DN4), an abridged qualitative pain questionnaire (QDSA) divided into a sensorial score (QDSAs) and an affective score (QDSAa), and a scale evaluating anxiety and depression (HAD) were recorded preoperatively, (T0), at 3rd postoperative day (PO), 1st (M1), 3rd (M2) and 6th (M6) postoperative month. Outcome was expressed as mean±SD or median and range.

Results: Eight men and 39 women, mean age 66.6±10.7 years were included. These patients. Fourteen of 47 (25.9%) had DCN postoperatively (2 DN4 successively ≥3). The “tingles” item for postoperative DN4 was significantly predictive of DCN (specificity 88.9%, sensitivity 83.3%). Preoperatively, the median intensity of pain was 6 (5–10) and was significantly higher in patients with DCN compared with those without DCN at M1 (4 [1–8] vs 3 [0–7]) and M3 (4 [1–8] vs 2 [0–6]) (p < 0,009) including 3/14 patients with Nu > 7 at M3. At M6, 12.7 % (n = 6/47) patients still had DN4 ≥3. The QDSAs score was higher in patients with DCN at M1 (11.8±4.4 vs 4.8±4.5; p < 0.001) and M3 (10.2±6 vs 3.5±3.2; p < 0.001). There was no significant difference between the QDSAa scores and the HAD.

Conclusion: The persistence of unusually intense pain after knee arthroplasty would suggest the pain could result from a neuropathological source which would require specific treatment because of the general insensitivity to analgesics.

Aims: We studied by means of a magnetic resonance imaging (MRI) protocol, the junction area between supratrochlear (ST) surface and the femoral trochlear groove (FT). The variations of this junction area are they correlated with the patientñs functional signs and with the patellar cartilage injuries?Method: We practised on 87 patients (64 patellar instability, 23 patellar pains) and 25 witnesses, an MRI: DESS and MPR sequences. The trochlear bump was studied in the sagittal plan according to the aspect of the junction area and in measuring itñs height. Results: The junction area was dismembered in 4 types according to its slope with the ST surface: ÒßatÒ, ÒroundÒ, ÒobliqueÒ and ÒsquareÒ. No atÒ typeÒßwas found in cases of FT dysplasia. The ÒobliqueÒ and ÒsquareÒ types were more frequent in cases of important projection of the FT (p< 0.0001). These two types were more frequently associated with the patellar cartilage injuries (p< 0.08). The trochlear projection was maximum (p< 0.0001) in FT dysplasia with spur, with a maximum effect in this case on patellar instability (p< 0.01) and also on patellar pain (p< 0.05). Conclusion: The junction area between the ST surface and the FT groove was dismembered in 4 types. A þrst ßat type without trochlear bump, and 3 types deþning a trochlear Òstep of stairÒ, round, square and oblique in order of growing gravity. The latter two were more common when patellar cartilage injuries existed.

Aims: Henri Dejour promoted a mechanism involving a third femoral condyle to achieve Posterior Stabilization (PS) in total knee arthroplasty (TKA) introducing the HLS II prosthesis. This retrospective study was conducted to assess the behavior of such PS mechanism. Methods: Between 1992 and 1993, 105 HLS II prostheses (94 patients) were consecutively inserted (78% arthrosis, 19% rheumatoid arthritis). No patient was lost for follow-up but 14 had died, 6 were unable to walk (severe neurological disorder), 4 were contacted by phone. Consequently, 70 patients (77 TKA) mean aged 66 years (22–79) were assessed after a mean follow-up of 7 years (6–8). All the components were fixed with cement and patellar resurfacing was always performed. Results: The knee IKS score increased from de 27 points [0–63] before surgery to 81 [21–100] at follow-up and functional IKS from 35 points [0–75] to 64 [0–100] (p< 0,0001). Similarly range of motion improved from 114° [60°–140°] to 116° [80°–135°] (NS). At follow-up, 86% of the patients were able to practice stairs (13% without support and 28% in alternative manner) against 52% before surgery (1% without support and 1% in alternative manner) (p=0,001). Tibial bone-cement radiolucencies were observed without loosening in 30% (all < 1 mm and non- progressive) mainly related to severe preoperative varus deformation (p = 0.01). One late infection required reoperation. Ninety months survival was 97% ± 1.3% with reoperation related to infection or mechanical disorder as end-point. Conclusion: The posterior stabilization, by means of a third condyle, allowed a satisfactory range of flexion and improved ability to practice stairs. Mid-term follow-up did not identified adverse effects of this PS mechanism on component fixation or knee stability.

Aims: Three methods of mobilization are currently performed: arthroscopic release (AR), manipulation under general anesthesia (MUGA), open surgical release (OSR). This study assessed the accurate indications of these 3 procedures to treat stiff knee arthroplasties. Methods: Sixty-two of these procedures were performed between 1989 and 2001 and followed at least 1 year: 34 MUGA, 18 AR and 10 OSR. The 3 groups were comparable excepted for the delay between the prosthetic insertion and the mobilization procedure: 17 weeks for MUGA, 46 weeks for AR, 97 weeks for OSR. All the patients had the same postoperative analgesia and rehabilitation program. Results: For the 62 procedures there was an improvement in range of ßexion from preop-erative (mean 58.4¡) to follow-up (mean 94.6¡) and a decrease in ßessum deformity from 7.6¡ to 2.5¡ (p= 0.001). From surgery to 1 year of follow-up, there was a decrease in ßexion (104.6¡ to 94.6¡) and an increase in ßessum deformity (1.3¡ to 2.5¡) (NS). The worst postoperative ranges of motion were observed at 6 weeks after the procedure, and then an improvement was observed up to 6 months but was non-signiþcant. Flexion did not improved beyond 6 months after the procedure. The results of the 3 techniques were not signiþcantly different. However, failures were more frequent when MUGA were performed beyond 8 weeks after prosthetic insertion, and when AR were performed beyond 6 months after prosthetic insertion (p< 0.01). Conclusions: We recommend to treat stiff total knee prostheses by MUGA until 8 weeks after insertion, by AR between 8 weeks and 6 months, and by OSR later on. This protocol addresses stiff prostheses without infection and without component malposition. The deþnitive ranges of motions were obtained at 6 months after mobilization.

Aims: This study compared in vivo kinematics of a posterior stabilized TKA inserted either with a fixed (FBC) or with a mobile bearing component (MBC). Methods: Ten patients with unilateral previously defined TKA were selected among 150 TKA performed in 2000 by a single surgeon according to the following criteria: primary TKA because of osteoarthritis, controlateral knee free of clinical symptoms, patient < 80, TKA flexion > 90°, knee IKS score > 80/100. Ten TKA (10 patients) were selected differing only by the adjunction of the mobile bearing (5 MBC and 5 FBC). The range of the 3 knee rotations (flexion, axial rotation, varus-valgus) were assessed by means of a 6-degree freedom electromagnetic goniometer during: level walking, rising from a chair, non weight-bearing flexion. Non-parametric tests compared motions between TKA and contro-lateral knee and between MBC and FBC. Results: FBC had a better mobility that MBC in valgus-varus, which was related to a larger frontal laxity. According to the increase in frontal laxity, FBC demonstrated better axial rotations that MBC in non-weight-bearing (NS). However, better ranges of axial rotation were recorded in MBC in weight-bearing (p< 0.05) (MBC axial rotation exceeded by 10° the motions of FBC). In patients with MBC, there was no difference in range of motion between the TKA and the controlateral healthy knee. In the FBC group the range of axial rotation was lower in the TKA by comparing with the controlateral knee (p< 0.05). Conclusion: With a unique prosthetic design our study suggests the role of MBC to reproduce a physiological range of axial rotation in weight-bearing. The MBC better reproduced knee kinematics Shoulder instability

Purpose: Independent cuts are generally used for tri-compartment knee prostheses but interdependent cuts may be needed. This can modify the height of the articular space or induce alignment errors. The purpose of this study was to examine the position of the implants, and the effects on laxity and lower limb alignment after implantation of a tricompartment knee prosthesis with a ligament tensor.

Material and methods: Between January 1998 and October 2000, 109 total knee prostheses (posterior stabilised Legacy®) were implanted in 94 patients. Three patients died, 3 who lived far from the centre were questioned by phone, 88 patients (103 prostheses) were retained for analysis at mean follow-up of 22.5 months. None of the patients were lost to follow-up. All of the prostheses in this series were implanted with a V-STAT® ligament tensor used to guide medial and lateral capsuloligamentary balance in flexion and extension under constant tension.

Results: At review, the IKS radiological scores were mean alpha 95.9° (90–108°) with 76.7% of the implants between 93° and 99°. The mean gamma angle was 1° (−8° to +8°) with 73.8% of the implants between −3° and +3°. The mean beta angle was 89.8° (86–98°) with 81.5% of the implants between 87° and 93°. Mean tibial slope measured from the mechanical tibial axis was 8.4° (2–15.5°) with 67% of the implants between 4° and 10° (desired slope 7°). The mean HKA at last follow-up was 178.8° (172.5–191°) with 75.7% of the knees between 175° and 185°. Correction was more significant for more pronounced preoperative deviation. The height of the articular space was significantly increased compared with the preoperative value. Mean radiological laxity in varus at last follow-up was 3.1° for a preoperative value of 2.8°. Mean radiological laxity in valgus at last follow-up was 3.2° for a preoperative value of 4°, a significant decrease. Mean sum of the radiological frontal laxities at last follow-up was 6.4° for a preoperative value of 6.8°, a non-significant decrease. Mean radiological sagittal laxity at last follow-up was 4.2 mm. There was no significant difference between preoperative and last follow-up sagittal laxity.

Discussion: The mean values obtained in this series are in agreement with data reported in the literature. While the height of the articular space was significantly greater at last follow-up, it was not correlated with a decrease in the height of the patella at last follow-up. Decreased patellar height at last follow-up was correlated with increased patellar joint surface (AP distance of the Blackburne and Peel index) and with shortened patellar tendons. Use of the V-STAT® ligament tensor allowed homogeneous mediolateral distribution of the frontal laxity while controlling sagittal laxity and preserving a normal axis of the lower limb.

Purpose: Use of a mobile tibial plateau for total knee arthroplasty (TKA) is designed to reduce wear and improve prosthetic kinetics. The purposes of this study were: 1) to compare the kinetics of a posterior stabilised TKA implanted with a fixed plateau (FP) or a mobile plateau (MP) and, 2) to determine whether the mobile plateau improves axial rotation.

Material and methods: Ten patients with a unilateral TKA (HLS) with a fixed or mobile plateau were selected for this study according to the following criteria: arthroplasty for degenerative knee disease, healthy contralateral knee, age < 80 years, pain-free prosthesis, IKS > 80/100, flexion > 90°, follow-up > 1 year. There were five patients with a fixed plateau and five patients with the same prosthesis except with a mobile plateau. Knee movement (flexion-extension, axial rotation, valgus-varus) were measured with an electromagnetic goniometer on the implanted and healthy sides. Four movements were recorded: walking, standing up sitting down, flexion-extension without loading. Amplitudes were compared with non-parameteric statistical tests between the healthy side and the implanted side and between the two types of implants

Results: The FP knees were more mobile in valgus-varus due to greater residual frontal laxity than the MP knees. This extra laxity generated excessive axial rotation on the FP during non-loaded movements. Conversely, when loaded, axial rotation of the MP knees was 10° greater (mean, p < 0.05) than for the FP knees, giving better stability in the frontal plane. This study did not demonstrate any difference in flexion between FP and MP. Patients with an MP prosthesis did not have significantly different amplitudes of the three movements for the healthy versus implanted knee. For the patients with a FP prosthesis, axial rotation and frontal plane movement was lower in the implanted knee than in the healthy knee (p< à.05).

Discussion: This study devoted to the design of a single prosthesis demonstrated the usefulness of the mobile plateau for axial rotation during loaded movement. The kinetics of MP prostheses is similar to that of the healthy knee. Better axial rotation with MP prostheses during loaded movements suggests the persistence of the plateau mobility which should be confirmed with a cinematographic study.

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: A new radiographic classification of the femoral trochlea was proposed by David Dejour in 1998 to quantify the severity of bony dysplasia. The purpose of this work was to evaluate the reproducibility of this classification system and to determine its contribution to the identification of trochlea with a high-risk of femoropatellar instability.

Material and methods: Nine independent observers (one resident, four junior surgeons, four senior surgeons) with no knowledge of the patient’s history read 68 strict lateral views of knees with femoropatellar instability (53 objective instabilities (OI) and 15 potential instabilities (PI)). The classification system includes four types determined with three signs: crossing (defining the dysplasia and present in all four types), supratrochlear spike, double contour. The four types are: type A crossing alone, type B crossing and spike, type C crossing and double contour, type D crossing, spike and double contour. The kappa test was used to assess reproducibility and chi square test to analyse data by category.

Results: Twenty-one radiographs were excluded by one or several observers due to insufficient quality or the impossibility to identify the signs of the new classification. Interob-server reproducibility assess on 47 radiographs was fair (kappa = 0.48). The crossing sign was identified by the nine observers on the 47 radiographs. Reproducibility of identification of the spike was good (κ= 0.62), but was fair for the double contour (κ = 0.51). there was no difference in reproducibility by level of experience of the observers. The new classification system was not correlated with severity of femoropatellar instability: presence of spike 80% OI, absence of spike 67% OI; presence of double contour 74% OI, absence of double contour 75% OI.

Discussion, conclusion: This new classification system is more reproducibly than the former 3-type system proposed by Henri Dejour. The crossing sign and the spike are the most reproducible signs. There presence is however insufficient to quantify the dysplasia and predict the severity of the femoropatellar instability. A quantitative measure of the depth of the trochlea, which shows excellent reproducibility (interclass coefficient 0.65) could be added to better quantify the morphological anomaly and determine the most adapted treatment.