Gait analysis following medial opening-wedge high tibial osteotomy.

PURPOSE: High tibial osteotomy (HTO) is used to treat young and active patients with knee osteoarthritis (OA) and varus deformity. The medial compartment OA alters the patients' gait. METHODS: A prospective study was carried out in 21 consecutive patients operated for HTO due to knee OA with varus deformity. There were 14 men and 7 women, with a median age of 51.9 years (38-64). Their gait was analyzed preoperatively and at 1 year postoperatively, and compared to a healthy control group. Clinical assessment (KOOS, WOMAC, Lysholm, and SF-36 scores) was also performed preoperatively and postoperatively. RESULTS: Patients with medial compartment OA had altered gait relative to the control population. Their walking speed was slower, step length was shorter, and single-leg stance time was shorter, while the double-leg stance time was longer (P < 0.001). Step width was not different between the two groups preoperatively (n.s.), but it was wider in the patient group postoperatively (P = 0.003). There were no differences in the patients' gait parameters before and after the osteotomy (n.s.). However, there was an improved perception of walking so that it is no longer different from controls (n.s.). The KOOS, WOMAC, Lysholm and SF-36 scores improved after HTO. The preoperative median of 7° varus (1-11) was corrected to 3° valgus (0-6). CONCLUSION: Medial compartment OA with varus deformity leads to gait modifications. HTO does not alter the time-distance parameters of gait; however, patients have improved perception of their walking ability. HTO leads to excellent results for knee function, and improves quality of life without modifying the gait pattern. LEVEL OF EVIDENCE: II.

Computer-assisted total knee replacement after medial opening wedge high tibial osteotomy: medium-term results in a series of ninety cases.

PURPOSE: The aim of this study was to evaluate the medium-term results of total knee replacements (TKRs) after medial opening wedge valgising tibial osteotomy to those of primary TKR (TKR1). The hypothesis being that there would be no difference in results between these groups. METHODS: Series 1 was made up of 45 TKRs after medial opening wedge high tibial osteotomy (MHTO)-30 men and ten women at an average age of 69 ± seven years (54-82). This was compared to a second series of TKR1s-30 men and ten women at an average age of 69 ± seven years (55-78). The average IKS scores were 91 ± 22.5 points (42-129) and 86 ± 18 points (38-116) in the two groups respectively. The average pre-operative HKA angle was 179 ± 5° (169-193°) in group 1, and 173 ± 7.5° (161-193°) in group 2. Tibial mechanical axes were 90.5 ± 4° (of which 24 knees had a valgus angle) and 85.05 ± 3.5° (79-93°) in the two groups respectively. RESULTS: All patients were reviewed at an average follow-up of 47 ± 24.5 months for series 1 and 185 ± 8.5 months for series 2. The average IKS score was 184 ± 6 for series 1 (172-200) and 185 ± 8.5 (163-200) for series 2 (p = 0.872). Thirty-seven patients in series 1 and 38 patients in series 2 were either extremely satisfied or satisfied with the intervention. The average post-operative HKA angle was 180.5 ± 2.5° and 181 ± 2° (p = 0.122) and the average tibial mechanical axis was 89 ± 1.5° against 90 ± 1° (p = 0.001). The results of the 24 knees with a valgus tibial mechanical axis were statistically no different. CONCLUSIONS: TKRs post medial opening wedge high tibial osteotomy have identical results to primary TKRs even in knees with a valgus tibial mechanical axis.

Computer navigation for revision of unicompartmental knee replacements to total knee replacements: the results of a case-control study of forty six knees comparing computer navigated and conventional surgery.

PURPOSE: The revision of unicompartmental knee replacements (UKRs) to total knee replacements (TKRs) using computer navigation is a little-known technique. The principal objective of this study was to analyse the radiological position of implants in revision of UKR to TKR comparing the results of surgery aided by computer navigation (CAS) with conventional surgery (CS). Our hypothesis was that computer navigation would improve the position of the implants. METHODS: This is a retrospective single surgeon series. Forty-six patients (46 knees) with an average age 73 ± eight years (53-93) between January 1995 and December 2014 were included. The two groups were made up of 23 patients each and are comparable in terms of age, sex, side of surgery, age of the UKR, cause of failure and HKA angle before surgery. All patients were reviewed by two independent observers. RESULTS: In the CAS group, the average hip-knee-ankle (HKA) angle was 179.2 ± 2.2° (175-184°). The average medial tibial mechanical angle (TMA) was 88.4 ± 1.6° (84-90°) and the medial femoral mechanical angle (FMA) was 91 ± 2° (87- 94°). The tibial slope was 88.7 ± 1.1° (87-90°). In the CS group, the average HKA angle was 179.9 ± 1.9° (175-183°), the TMA was on average 89.1 ± 1.3° (87-93°) and the FMA was 90.6 ± 1.5° (87-93°). The tibial slope was 87.8 ± 4.9° (85-95°). There was no statistically significant difference between the two groups on any of the radiological parameters studied. CONCLUSIONS: Our radiological target of a post-operative HKA angle of 180 ± 3° was obtained in 87.5% of cases in the CS group and 92.4% of cases in the CAS group. This slight difference in favour of the computer-assisted group was not statistically significant, and we cannot therefore confirm our initial hypothesis, at least in the hands of an experienced surgeon. However, the quality of the results in the CAS group suggest that this technique could provide precious assistance to less experienced surgeons performing this surgery.