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.

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.