Age-related changes of micro-morphological subchondral bone properties in the healthy femoral head

OBJECTIVE

Alterations in the subchondral bone (SCB) are likely to play a decisive role in the development of osteoarthritis (OA). Since aging represents a major risk factor for OA, the aim of the current study was to assess the microstructural changes of the subchondral bone in the femoral head during aging.

DESIGN

Femoral heads and matched iliac crest biopsies of 80 individuals (age 21-99 years) were collected post-mortem. The bone microstructure of the subchondral trabecular bone as well as the cartilage thickness (Cg.Th) and subchondral bone plate thickness (SCB.Th) were quantified using histomorphometry. The different subregions of the SCB were also imaged by quantitative backscattered electron imaging (qBEI) in 31 aged cases to assess the bone mineral density distribution (BMDD).

RESULTS

The detected linear decline of bone volume per tissue volume (BV/TV) in the femoral head with aging (Slope, 95% CI: -0.208 to -0.109 %/yr.) was primarily due to a decrease in trabecular thickness (Tb.Th, Slope, 95% CI: -0.774 to -0.343 μm/yr). While SCB.Th declined with aging (Slope, 95% CI: -1.941 to -0.034 μm/yr), no changes in Cg.Th were detected (Slope, 95% CI: -0.001 to 0.005 mm/yr). The matrix mineralization of the subchondral bone was lower compared to the trabecular bone and also decreased with aging.

CONCLUSIONS

Regular changes of the SCB during aging primarily involve a reduction of Tb.Th, SCB.Th and matrix mineralization. Our findings facilitate future interpretations of early and late OA specimens to decipher the role of the SCB in OA pathogenesis.

[Should we use hip-ankle radiographs to assess the coronal alignment after total knee arthroplasty?]

BACKGROUND

There is no consensus on whether hip-ankle radiographs or rather standardized a‑p knee-radiographs should be used to assess implant position and coronal alignment after total knee arthroplasty (TKA). This study investigates whether implant position and alignment after TKA can reproducibly be assessed using a‑p knee-radiographs rather than hip-ankle radiographs.

MATERIALS AND METHODS

This study was performed on 100 weight-bearing hip-ankle radiographs after conventional primary TKA. The true mechanical and anatomical femorotibial angle as well as coronal implant position was assessed on hip-ankle radiographs. The radiographs were then cropped to 80, 60 and 40 % of the leg-length and tibial coronal implant position, and the anatomical axis and a surrogate mechanical axis were obtained. The difference in the alignment parameters between the hip-ankle radiographs were statistically compared with the cropped radiographs and the inter-observer correlation coefficient (ICC) was calculated.

RESULTS

The ICC for measurement of the mechanical femorotibial angle was higher in hip-ankle radiographs (0.95) when compared with a radiograph cropped to 40 % (0.61). There was a significant difference in the mechanical femorotibial angle between hip-ankle radiographs and any cropped radiograph. However, there were no significant differences in coronal implant position and the anatomical femorotibial angle between hip-ankle radiographs and any cropped radiograph.

CONCLUSIONS

We conclude that standard a‑p knee-radiographs are insufficient to assess the mechanical alignment following TKA. However, standard a‑p knee-radiographs are appropriate to assess the implant position when referenced against the anatomical axes. Weight-bearing hip-ankle radiographs should be questioned as a routine after TKA.

The relationship between initial closed reduction and the surgical reconstruction of the radiocarpal joint line in distal radial fractures

INTRODUCTION

Whilst initial closed reduction followed by definitive open fixation is widely applied in the treatment of distal radial fractures, the effect of the closed reduction on the reconstruction of the articular surface remains unclear. Our research questions were:

METHODS

Palmar tilt and radiocarpal inclination of 425 patients were measured at admission, following initial closed reduction and after surgical reconstruction.

RESULTS

Closed reduction increased palmar tilt by 12.1° and radial inclination by 2.7°. Open surgical reduction further corrected palmar tilt by 17.88° and radial inclination by 3.5°. Whilst there was no association between postoperative palmar tilt and initially achieved closed reduction, a significant association between radial inclination following closed reduction and surgical fixation was found.

CONCLUSION

Our retrospective study challenges the existence of a relationship between the initial closed reduction and the reconstruction of the anatomic joint line in surgically treated distal radial fractures.

[Bilateral Ischiofemoral Impingement: A Case Report]

Ischiofemoral impingement (IFI) is a rare cause of hip pain and was first described in 1977. While it can be related to trauma, it may also be idiopathic. We report a case of IFI in a 22-year old female, who was successfully treated by resection of the lesser trochanter. However, 8 months later, symptoms recurred on the contralateral side. Surgical intervention was required to alleviate the patient's symptoms. This case report discusses the clinical, diagnostic and therapeutic features of IFI.

Ceramic-on-polyethylene bearing surfaces in total hip arthroplasty. Seventeen to twenty-one-year results

BACKGROUND

Polyethylene wear debris, and the resulting inflammatory response leading to osteolysis and loosening, is the primary mode of failure limiting the longevity of total hip replacements. Alternative bearing surfaces, including ceramic-on-polyethylene, have been investigated in an effort to decrease the amount of polyethylene wear debris. The purpose of this study was to evaluate the seventeen to twenty-one-year results of the use of ceramic-on-polyethylene total hip prostheses.

METHODS

Sixty-four total hip prostheses were implanted with cement, by one surgeon, in fifty-six patients from 1978 to 1981. The average age at the index arthroplasty was sixty-nine years (range, fifty-one to eighty-four years). The components consisted of a cemented Charnley-Müller stem with a 32-mm modular alumina femoral head and a cemented all-polyethylene acetabular component. All patients who retained the index prosthesis were assessed clinically with use of Harris hip scores and were evaluated radiographically at the time of the latest follow-up.

RESULTS

At the time of this latest follow-up, of the original sixty-four implants, eighteen (28%) were still in place and five (8%) had been revised. The remaining forty-one implants were in patients who had died and were functioning well until the patient's death. No patient was lost to follow-up. Of the eighteen hips with an intact prosthesis in the surviving patients, seven had an excellent clinical result; nine, a good result; and two, a fair result. One asymptomatic hip had definite radiographic evidence of femoral loosening. No hip had definite signs of acetabular loosening or evidence of osteolysis. Survivorship analysis revealed that the probability of survival of the prostheses without revision was 95% at five years, 95% at ten years, 89% at fifteen years, and 79% at twenty years. The mean linear and volumetric polyethylene wear rates were 0.034 mm/yr and 28 mm(3)/yr, respectively. There were no fractures of the ceramic heads.

CONCLUSIONS

Outstanding long-term clinical and radiographic results were attained despite the use of what are now considered substandard techniques (an inferior stem design, a 32-mm head, and first-generation cementing techniques). The wear rates in this study are lower than previously reported metal-on-polyethylene wear rates and are consistent with the lowest reported in vivo ceramic-on-polyethylene wear rates. These findings support the consideration of ceramic-on-polyethylene bearing surfaces in total hip arthroplasty.

Incidence of posthospitalization proximal deep venous thrombosis after total hip arthroplasty. A pilot study

The incidence of venous thromboembolic disease after hospitalization for elective total hip arthroplasty (THA) was evaluated in a prospective pilot study of 42 patients. Before discharge from the hospital, all patients were free of deep venous thrombosis (DVT) (bilateral lower extremity ascending venography, 38 patients; duplex ultrasonography, two patients; or a combination of both, two patients). After discharge from the hospital, each patient had bilateral duplex ultrasonography and clinical evaluation monthly for three months. Venography was performed when the noninvasive test suggested the presence of DVT. Four (10.5%) of 38 completed patients (95% confidence interval, 4.4-24.8%) developed proximal DVT after hospitalization. Two episodes occurred during the first month after discharge and two during the second month. Three of the four episodes involved the surgically treated extremity. This pilot experience suggests that a significant risk of DVT continues for at least two months after THA. This observation adds support for the emerging clinical trend to continue DVT prophylaxis for at least two months after hospitalization. Further study regarding the incidence of late DVT and its effective prophylaxis seems warranted.