Function and satisfaction after total knee arthroplasty (TKA) are partially linked to postoperative range of motion (ROM). Fixed flexion contracture is a recognized complication of TKA that reduces ROM and is a source of morbidity for patients. This study aimed to identify preoperative risk factors for developing fixed flexion contracture following TKA and to quantify the effect of fixed flexion contracture on outcomes (Oxford knee score 12-60 and patient satisfaction) at 2 years. Pre-, intra-, and postoperative data for 811 TKAs were retrospectively reviewed. At 2 years postoperatively, the incidence of fixed flexion contracture was 3.6%. Men were 2.6 times more likely than women to have fixed flexion contracture (P=.012), and patients with preimplant fixed flexion contracture were 2.3 times more likely than those without to have fixed flexion contracture (P=.028). Increasing age was associated with an increased rate of fixed flexion contracture (P=.02). Body mass index was not a risk factor (P=.968). Incidence of fixed flexion contracture for those undergoing computer navigated TKA was 3.9% compared with 3.4% for those having conventional surgery (P=.711). Patients with fixed flexion contracture had poorer outcomes with a median [interquartile range] Oxford Knee Score of 25 [15] compared with 20 [11] for those without (P=.003) and lower patient satisfaction (P=.036). These results support existing literature for incidence of fixed flexion contracture after TKA, risk factors, and outcomes, indicating that these figures can be extrapolated to a wide population. They also clarify a previously contentious point by excluding body mass index as a risk factor.

ObjectivesAcetabular component orientation in total hip arthroplasty (THA) influences results. Intra-operatively, the natural arthritic acetabulum is often used as a reference to position the acetabular component. Detailed information regarding its orientation is therefore essential. The aim of this study was to identify the acetabular inclination and anteversion in arthritic hips.MethodsAcetabular inclination and anteversion in 65 symptomatic arthritic hips requiring THA were measured using a computer navigation system. All patients were Caucasian with primary osteoarthritis (29 men, 36 women). The mean age was 68 years (SD 8). Mean inclination was 50.5° (SD 7.8) in men and 52.1° (SD 6.7) in women. Mean anteversion was 8.3° (SD 8.7) in men and 14.4° (SD 11.6) in women. ResultsThe difference between men and women in terms of anteversion was significant (p = 0.022). In 75% of hips, the natural orientation was outside the safe zone described by Lewinnek et al (anteversion 15° ± 10°; inclination 40° ± 10°).ConclusionWhen using the natural acetabular orientation to guide component placement, it is important to be aware of the differences between men and women, and that in up to 75% of hips natural orientation may be out of what many consider to be a safe zone.Cite this article: Bone Joint Res 2015;4:6–10.

Objective Prosthetic joint infections provide a complex challenge for management, owing to their often difficult diagnoses, need for multiple surgeries, and increased technical and financial requirements. The ‘2 in 1’ single-stage approaches have been recently advocated in the field of arthroplasty on account of their reduction in risks, costs, and complications. The aim of our study was to investigate the outcomes of this variant of single-stage revision, which is used in the setting of infection following primary total knee replacement (TKR) and associated bone loss. Methods Prospective data were collected from all patients presenting with an infection following primary TKR over an 8-year period (2009–2017). We examined revision procedures that were undertaken as a single-stage procedure and had bone loss present. Patients were followed-up for evidence of recurrent infection. Functional assessments were conducted using range of motion, Oxford Knee Score (OKS), American Knee Society Score (AKSS), and Short Form-12 (SF-12) survey. Results Twenty-six patients were included in the analysis, two of whom had previously failed 2 stage revision; another three among them had failed debridement, antibiotics, irrigation, and implant retention procedures. The mean age was 72.5 years, mean body mass index was 33.4, and median American Society of Anesthesiologists (ASA) physical status classification was 2. The mean time to revision was 3.5 years (3 months to 12 years). Six patients had actively been discharging sinuses at the time of surgery. Only 4/26 patients possessed no positive microbiological cultures from deep tissue samples or joint aspirates. One patient was afflicted with a recurrence of infection. This patient did not require further surgery and was successfully treated with the help of long-term antibiotic suppression. There were statistically significant improvements in both the pain component of AKSS scores (preoperative 4.3 to postoperative 32.4) and the functional component of AKSS scores (preoperative 10.7 to postoperative 15.7). There was no significant improvement in flexion; however, mean extension (increased from 18.5 to 6.9 postoperative) and total range of motion (increased from 69.2 preoperative to 90.3 postoperative) both showed statistically significant improvements. Conclusion The use of “2-in-1” single-stage revision can be considered as an effective option for treating infection following TKR and associated bone loss.

The aim of this study was to assess the rate of collateral soft tissue release required in navigated total knee arthroplasty (TKA) to achieve an intra-operative coronal femoral tibial mechanical axis (FTMA) in extension of 0 ± 2°. The primary outcomes assessed were post-operative coronal plane alignment and rate of collateral soft tissue release. The secondary outcomes were range of motion, function, patient satisfaction, and complication rates at one-year follow-up. This is a prospective study of 224 knees. No exclusions were made on the basis of pathology or severity of deformity. Pre-operative FTMA ranged from 27° valgus to 25° varus (mean: −4.5° SD 7.6). Soft tissue release was carried out in 5 of 224 knees (2.2%). Post-operative weight-bearing radiological FTMA ranged from 7° valgus to 8° varus (mean: −0.4° SD 2.5°). Two hundred and ten knees (96%) were within 0 ± 5° of neutral. At one year, median maximum flexion was 100° (IQR 15°) and extension was 0°; mean post-operative Oxford Knee Score had improved from 42 to 23; and 91% of patients were satisfied or very satisfied, with only 2% being dissatisfied. We have found that in the vast majority of cases, including those with large pre-operative coronal deformity in extension, good outcomes in terms of coronal alignment, range of movement, function and patient satisfaction can be achieved.

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