The significance of weight in the indications for unicompartmental knee replacement (UKR) is unclear. Our hypothesis was that weight does not affect the long-term rate of survival of UKRs.

We undertook a retrospective study of 212 UKRs at a mean follow-up of 12 years (7 to 22). The patients were distributed according to body mass index (BMI; < vs ≥ 30 kg/m²) and weight (< vs ≥ 82 kg). Kaplan-Meier survivorship analysis was performed and ten-year survival rates were compared between the sub-groups. Multimodal regression analysis determined the impact of the various theoretical contraindications on the long-term rate of survival of UKR.

The ten-year rates of survival were similar in the two weight subgroups (≥ 82 kg: 93.5% (95% confidence interval (CI) 66.5 to 96.3); < 82 kg: 92.5% (95% CI 82.5 to 94.1)) and also in the two BMI subgroups (≥ 30 kg/m²: 92% (95% CI 82.5 to 95.3); < 30 kg/m²: 94% (95% CI 78.4 to 95.9)). Multimodal regression analysis revealed that weight plays a part in reducing the risk of revision with a relative risk of 0.387, although this did not reach statistical significance (p = 0.662). The results relating weight and BMI to the clinical outcome were not statistically significant. Thus, this study confirms that weight does not influence the long-term rate of survival of UKR.

Cite this article: Bone Joint J 2013;95-B:1064–8.

Background

Floating shoulder (FS) is, according to Goss et al, a double disruption of the superior shoulder suspensory complex which usually results from a glenoid neck fracture and a ipsilateral midclavicular fracture. However, the interruption can interest the whole scapular belt from acromion to sterno-clavicular joint. It occurs mostly after a violent traumatism with direct lateral impact on the shoulder. That leads to complex therapeutic issues with sometimes uncertain results.

Background: Acetabular implant revision with large bone defects, can be challenging. One of the reconstruction options is a “jumbo cup” (outer diameter ≥62mm in women and ≥66mm in men). We hypothesized that cementless jumbo cups is a reliable technique to reconstruct hip joint with satisfying radiological and clinical outcomes.

Material and Methods: Fifty-two consecutive acetabular revisions arthroplasty where a cementless jumbo cup was used were assessed. Clinical outcomes were assessed by Harris Hip Score (HHS), WOMAC index and SF-12. Hip centre was assessed on anteroposterior (AP) view according to Pierchon’s criteria. The reconstructed hip center was considered as satisfying when its location was located from −10 to + 10 mm proximally (y axis) and/or medially (x axis) in comparison with ideal theoretical hip center location. Cup migration and modification of abduction angle were considered as significant when there were respectively ≥5mm and to ≥5° in comparison with the immediate postoperative AP view.

Results: Mean component size was 67.6 mm (min 62, max 81). According to Paprosky classification, there were 5 cases of type 1, 11 type 2A, 12 type 2B, 11 type 2C, 11 type 3A and 2 type 3B. Cancelous bone chips allograft were used in 34 cases and bulk bone allograft in 14. Immediate postoperative AP view showed a mean abduction cup angle of 41.3° (26–53), a satisfying hip centre positioning in 78% on x axis and in 70 % on y axis. In the remaining cases, we noted an improved implant positioning. For the patients with intact contra-lateral hip (n=29), we noted, in comparison with normal side, a mean lateralisation of the hip center of 3 mm (−10 – +16) and a mean ascension of 7 mm (−10 – +33) associated with an average limb length discrepancy of – 4 mm (−19 – +9). At the last follow up [radiological data: 79 months (24–236) and clinical data: 88 months (27–241)], 6 patients were died and 3 were lost of follow up. The mean HHS was 82% (15–100), WOMAC 86% (27–100), SF-12 46 (14–61) and 53 (15–63). Bone graft integration was completed in all but 3 cases. Significant cup migration (≥5mm) occurred in only one case. The complications were: dislocation in 5 cases (4 revisions with constrained liner), infection in 4 cases (2 treated conservatively and 2 revised in 2 times procedure) and Brooker’s type III or IV ectopic ossifications in 11 cases. No case required revision for aseptic loosening.

Discussion: Jumbo cups appear as a reliable procedure to manage bone loss in acetabular revision. The complication rate is comparable with other reconstruction procedures (massive allograft, reinforcement rings, high hip center…). Cementless fixation and satisfying hip center restoration promote respectively the bone integration and allow an optimal biomechanical joint functioning. These are the main conditions for high long term survival rate.

Introduction: Double mobility acetabular implant has a semicircular shape, it is covered with hydroxyapatite, the entire surface has a thickness of 3 mm and its centers of rotation are shifted.

The polyethylene employed is a high density one and it has some chanfers to avoid the cam effect.

Methods and materials: We present the results o an homogeneous series of 200 patients, operated between 2003 and 2007. Clinical and radiographic parameters were analyzed prospectively. The mean follow-up was done during 15 months. Clinical results were evaluated by the HHS at the out patients clinics: previous and post surgery.

Results: From the 200 patients operated (130 women-70 men / Mean age: 81 years old): 57,63% had a primary hip osteoarthritis; 5,77 % femoral necrosis ; 1,13 % rheumatoid arthritis; 16,95 % revision surgeries; 13,45% femoral neck fractures; 3,2% acetabular fractures y 1,5 % hip tumours.

HHS before surgery was 45, 83 points on average (from 12 to 79) y post surgery HHS was 80, 03 points (from 37 to 100), increasing the total score after the arthroplasty in a mean of 34, 17 points

Post surgery complications were as follow: 3 dislocations (1 after an enormous fall and 2 in patients with Alzheimer. In our series there are 50 patients diagnosed of dementia-Alzheimer); 1 per prosthetic fracture (revision surgery); 4 deep infections (2 acute: lavage+ antibiotherapy; 2 late ones: spacer + antibiotherapy +second time surgery); 2 Deep vein thromboses (Eco Doppler +) ; 10 urinary infections; 2 urinary retentions and 17 deaths.

Discussion: Double Mobility acetabular implant has shown good results in all the following indications: Revision surgery, hip osteoarthritis, femoral necrosis, Rheumatoid arthritis, femoral neck and acetabular fractures, hip tumours and as an implant for Computer Assisted Hip Surgery.

Conclusions: The complications founded while this acetabular implant is used appeared with the same percentage than others. The dislocation rate is lower than standard acetabular implants, especially in patients with neuromuscular or cognitive illnesses.

Those clinical results are hopeful and they could increase the number of actual indications (hip osteoarthritis in people over 70 years old, multiple illnesses associated, iterative dislocations…) for the double mobility implant on the future.