No adverse effects of early weight bearing after uncemented total hip arthroplasty: a randomized study of 20 patients

BACKGROUND: Few guidelines are available whether early weight-bearing after an uncemented total hip arthroplasty (THA) can be recommended or not. Stability and ingrowth may be jeopardized by immediate loading of the implant while functional recovery may be promoted and periprosthetic demineralization reduced. PATIENTS AND METHODS: We did a prospective study of 20 patients who were operated on with a hydroxyapatite-coated (HA), uncemented total hip arthroplasty with a tapered stem because of unilateral arthrosis, and randomized the patients to the immediate (I) or late (L) weight-bearing (after 3 months) group. The shoe on the operated side was equipped with an auditory device signaling when the patient placed a load on the extremity. The clinical assessment was done with the Harris hip score at the time of the operation and after 12 and 24 months. Radiographs and dual-energy x-ray absorptiometry (DEXA) were evaluated for migration, femoral remodeling and bone mineral density (BMD) after 3, 6, 12 and 24 months. Tc-scintigraphy was done after 6, 12 and 24 months. RESULTS: Postoperatively, the Harris hip score showed no group difference. After 3 months, we noted a large reduction in BMD around the stem prosthesis. This was most marked in the proximal regions and the bone loss was significantly larger in zone 1, 4 and 5 in the L group. Distally, the BMD normalized with time, but the loss of bone persisted in the proximal zones after 24 months. An initial increase in the scintigraphic uptake ratio in all zones in both groups declined with time, but it was still increased on the operated side after 24 months. Several radiographic signs of bone remodeling were seen, but the patterns were similar in both groups. INTERPRETATION: We found no adverse effect of immediate weight bearing with this prosthesis.     

生物型假体全髋置换术后早期负重近期效果

目的 探讨生物型全髋置换早期下床负重的可行性.方法 将56例年龄≤70岁的生物型假体全髋置换术后患者随机分成早期负重组(27例)和晚期负重组(29例),所有病例均采用小切口微创技术.早期负重组术后1周内下床拄拐自由负重,晚期负重组术后6周后下地负重,分别对两组进行术后6周和3、6、12、24个月的临床和影像学随访.髋关节功能按Harris评分,并对评分结果进行统计学分析.结果 术后6周、3个月的Harris评分早期负重组为(71.9±10.2)分、(87.6±9.4)分,晚期负重组为(60.3±9.1)分、(74.0±12.0)分,早期负重组明显高于晚期负重组(P＜0.01),Xx线最后随访时假体无松动、下沉;晚期负重组有2例患肢深静脉血栓形成.结论 在保证术中假体初始稳定性的前提下,生物型全髋置换术后可以早期下床负重;近期能明显促进患肢的功能恢复,预防下肢深静脉血栓形成.     

Unrestricted weight bearing and intensive physiotherapy after uncemented total hip arthroplasty.

BACKGROUND AND AIMS: The effectiveness of partial weightbearing after hip surgery has been questioned as well as the need of intensive physiotherapy. MATERIAL AND METHODS: 36 patients (average age 54.4, 19 women) operated with uncemented hip arthroplasty were randomized either to unrestricted weightbearing (UWB) combined with intensive physiotherapy or to partial weightbearing (PWB) for 3 months combined with a short self-training program. The load during walking and the muscle strength (MS) in abduction was measured preoperative and subsequent up to 12 months. RESULTS: The average peak load on the operated leg at one week was 39.0 kg for the UWB and 25.8 for the PWB group (P = 0.009) while at three months 70.0 and 31.7 (P = 0.001) respectively. At 6 and 12 months there were no differences between the groups. The muscle strength increased in both groups up to six months but there were no differences between the groups. CONCLUSIONS: Even though patients applied more load than the recommended 15 kg most patients were able to comply with partial weightbearing fairly well. The effect of intensive physiotherapy on the muscle strength after hip arthroplasty is questionable.     

Periacetabular bone changes after uncemented total hip arthroplasty evaluated by quantitative computed tomography

Background?There are few dual X-ray absorptiometry (DXA) studies on periacetabular bone density changes after cup implantation. This study was designed to analyze the load-transfer mechanism and stress pattern of periacetabular cortical and cancellous bone after implantation of a ihemispherical titanium alloy press-fit cup with alumina-alumina pairing in vivo. We introduced a novel method of computed tomography (CT)-assisted osteodensitometry.

Method?We investigated 26 hips (26 patients) with osteoarthritis using conventional sequential CT examinations performed within the first 10 days after implantation, and after a mean period of 1.1 years postoperatively. Bone density of full, cancellous and cortical bone (mgCaHA/mL) was measured.

Results?At the time of follow-up, the mean bone density values of the cortical bone cranial to the cup increased by 3.6% (p = 0.03) while the cancellous bone density decreased by 18%. Cancellous bone loss was greater in the region ventral to the cup (–35%) than in the dorsal region (–30%). Cortical bone density decreased ventral to the cup (–6.4%). All these changes were statistically significant. The bone density changes in the dorsal cortical region were not significant.

Interpretation?The method presented is an excellent tool for detailed measurement of bone density changes around the cup after total hip arthroplasty, and allows a thorough assessment of stress shielding phenomena in vivo. The hemispherical titanium alloy press-fit cup is a rigid implant which stress shields cancellous bone and enhances load transfer to the cranial cortical bone. Further investigations will demonstrate the impact these factors have on the long-term results of the implant, and may allow a type-related predictable prognosis of the longevity of the prosthesis.     

Immediate or late weight bearing after uncemented total hip arthroplasty: A study of functional recovery

Late weight bearing on the operated leg after uncemented total hip arthroplasty may slow the patient's rehabilitation. The aim of this study was to find out whether 12 weeks of non-weight-bearing gait had any influence on passive hip extension, muscle strength, gait velocity, pain, and walking pattern during the first 24 postoperative weeks. There were no significant differences in results 24 weeks after surgery between 10 patients with late weight bearing and 11 patients with immediate weight bearing. As expected, however, there was a difference in muscle strength between the operated and the nonoperated leg. This study shows no evidence that late weight bearing after uncemented total hip arthroplasty implies any serious adverse effects on functional recovery after 24 weeks compared with immediate postoperative weight bearing.     

Early weight bearing after uncemented total hip prostheses--an analysis of acetabulum cup migration]

PURPOSE: The postoperative mobilisation after cementless total hip arthroplasty is usually non-weight bearing within the first six weeks to achieve bony ingrowth for the implant. Since 1995 weight bearing mobilisation is performed at our clinic even after cementless implantation of the Alloclassic (Zweymüller-Sulzer) system. The aim of the presented study was the detection of any negative influence of weight bearing mobilisation on the stability of this cementless implant. METHOD: The horizontal and vertical cup migration of 42 cementless acetabular cups (Alloclassic Zweymüller-Sulzer) in 40 patients after weight bearing mobilisation and a minimum follow up of 24 months were analysed by a digital migration analysis. The results were compared to a normative migration profile of the same that was recently established. RESULTS: The migration analysis did not exceed the level of accuracy of 1.3 mm in any patient. The mean horizontal cup migration was 0.3 mm in both groups after 24 months, the mean vertical migration was 0.4 mm in both groups. No significant difference of the acetabular stability was detectable. None of the implants showed radiological signs of loosening or migration. CONCLUSION: The presented data justify an early postoperative weight bearing mobilisation using the cementless Alloclassic threated cup, provided that primary stability of the implant can be achieved.     

Immediate weight bearing after uncemented total hip arthroplasty with an anteverted stem: a prospective randomized comparison using radiostereometry

BACKGROUND: In uncemented total hip arthroplasty with hydroxyapatite coating, early weight bearing is frequently practiced but there is still not much evidence to support this recommendation. METHOD: In a prospective randomized study we evaluated the effect of partial and full weight bearing after cementless total hip arthroplasty (ABG; Stryker-Howmedica) using radiostereometric analysis (RSA). Between February 1996 and February 2000, 43 consecutive patients (mean age 53 (41-63) years, 23 women) with hip osteoarthrosis received an uncemented and hydroxyapatite-coated prosthesis with an anteverted stem. All patients were operated in a standardized way by three experienced surgeons and they were randomized to partial (P) or full (F) weight bearing during the first 6 weeks after surgery. The patients in the partial weight bearing group were equipped with a pressuresensitive insole signaling when their load exceeded the prescribed weight limit. RESULTS: At 3-month follow-up, the mean proximal (+)/ distal (-) migration of the stem was -0.14 mm (-1.93- 0.11) in group P and -0.31 mm (-4.30-0.16) in group F (p=0.6). At 1-year follow-up, the mean migration was -0.17 mm (-2.18-0.21) and -0.28 mm (-4.31-0.11), respectively (p=0.9). There was no significant difference in stem rotations either (p<0.2). The cup translations, rotations, and femoral head penetration were similar in the two groups (p<0.1). There were no re-operations during the first year. INTERPRETATION: We did not find any adverse effect of full weight bearing immediately after operation, which justifies use of this regimen after uncemented total hip arthroplasty of the ABG type.     

The effect of early weight bearing on migration pattern of the uncemented CLS stem in total hip arthroplasty

Forty-two patients (younger than 65 years) with osteoarthritis were operated on with an uncemented CLS stem and randomized to early unrestricted weight bearing combined with intensive physiotherapy or to partial weight bearing combined with self-training. Radiostereometric analysis showed 1.2 (+0.11 to -6.76) mm subsidence of the stem at 24 months in both groups. There was no significant difference in the migration pattern between the unrestricted and partial weight bearing groups. Actual loading on the operated leg, measured with the F-scan system, did not influence the migration of the stem. There was a strong correlation between the average subsidence at 3 and 24 months (r = 0.96). Early full weight bearing and active rehabilitation can be used for the uncemented CLS stem without increased risk of early loosening.     

Repair of Bone Defects by Bone Inductive Material

Experimental fibular defects in 16 rats were filled with an acid decalcified homogenous bone matrix (bone inductive material). Autogenous bone grafts in corresponding defects in the other legs of the same rats served as controls. After 3 months, 11 of the 16 defects filled with bone inductive material healed with bony union, but only 4 of the 16 defects treated with autogenous bone grafts had healed. The results suggest that bone inductive material can repair bone defects which are too large to be healed by autogenous bone grafts.     

The natural history of osteoarthritic bone cysts after uncemented total hip arthroplasty

This study quantified the radiographic changes of osteoarthritic acetabular bone cysts after uncemented total hip arthroplasty (THA). Ten-year follow-up radiographs from 130 primary THAs were reviewed. Forty-one cysts were identified on immediate postoperative radiographs. Two-dimensional cyst size was measured postoperatively and on long-term radiographs. Mean initial cyst size was 1.0 +/- 0.9 cm(2). Four (10%) of the 41 cysts expanded over time. The average increase in cyst size was 5.1 +/- 8.6 cm(2) which equated to a mean size increase of 713%. Twenty-seven cysts (66%) shrank, and the remaining 10 cysts (24%) did not change with time. Because cysts located in zone II, near the dome hole of the cup, were statistically more likely to progress, we hypothesize that these cysts communicated with the joint space via these holes. We propose that placing the acetabular component to seal an osteoarthritic cyst from the joint space during THA can help prevent its subsequent progression and the risk of associated osteolysis.     

Tranexamic acid reduces blood loss and blood transfusions in primary total hip arthroplastyA prospective randomized double-blind study in 40 patients

Introduction: We performed a prospective, randomized, double-blind study on 40 patients scheduled for primary total hip arthroplasty due to arthrosis or osteonecrosis to determine the effect of tranexamic acid on per- and postoperative blood losses and on the number of blood transfusions needed. Patients and methods: 40 patients were randomized to tranexamic acid (10 mg/kg given as a bolus intravenous injection, followed by a continuous infusion of 1 mg/kg/hour for 10 hours) or placebo (20 mL saline given intravenously) 15 minutes before the incision. We recorded the peroperative and postoperative blood losses at removal of the drain 24 hours after the operation and the number of blood transfusions. Results: Patients receiving tranexamic acid had a mean peroperative blood loss of 480 mL versus 622 mL in patients receiving placebo (p= 0.3), a postoperative blood loss of 334 mL versus 609 mL (p= 0.001), a total blood loss of 814 mL versus 1231 mL (p= 0.001) and a total need for 4 blood transfusions versus 25 (p= 0.04). No patient in either group had symptoms of deep venous thrombosis, pulmonary embolism or prolonged wound drainage. Interpretation: Transemic acid is effective in reducing the postoperative blood loss, the total blood loss and the need for blood transfusion in primary total hip arthroplasty.     

Alendronate reduces periprosthetic bone loss after uncemented primary total hip arthroplasty: a prospective randomized study.

Periprosthetic bone loss, especially in the proximal part of the femur, is common after cemented and uncemented total hip arthroplasty (THA). Bone loss can be progressive and, in the extreme, may threaten survival of the prosthesis. To study whether alendronate therapy can reduce bone loss adjacent to prostheses, 13 uncemented primary THA patients were randomized to the study. They received 10 mg alendronate + 500 mg calcium (n = 8) or 500 mg calcium only (n = 5) daily for 6 months follow-up after THA. Periprosthetic bone mineral density (BMD) was measured with dual energy X-ray absorptiometry (DXA). Decreases in periprosthetic BMD in the alendronate-treated group were lower compared with the changes in the calcium-only group in the same regions of interest at the same follow-up time. In the proximal femur, the mean BMD decrease was 17.1% in the calcium-only group, whereas in the alendronate-treated group the decrease was only 0.9% (p = 0.019). The mean periprosthetic BMD change was also significantly different in the total periprosthetic area between the study groups at the end of the follow-up (calcium-only group -9.9% vs. alendronate-treated group -2.6%; p = 0.019). Alendronate therapy led to a significant reduction in periprosthetic bone loss after primary uncemented THA compared with the changes found in patients without therapy. This kind of bone response may improve the support of the prosthesis and may result in better survival of the prosthesis. However, in this study the follow-up time was too short and the study population was too small to make any long-term conclusions as to the prognosis for THA patients treated with alendronate.     

Reduced survival for uncemented compared to cemented total hip arthroplasty after operatively treated acetabular fractures

BackgroundPost traumatic arthritis and avascular necrosis of the femoral head are common complications after operatively treated acetabular fractures. This may cause severe disabilities for the patient, necessitating a total hip arthroplasty. Even though an arthroplasty may provide good symptomatic relief, the long-term results are more uncertain and no consensus exists according to preferred prosthetic designs. With this cohort study, we aimed to investigate the medium to long term arthroplasty survival and clinical results of total hip arthroplasty after operatively treated acetabular fractures.MethodsWe included 52 patients treated with a secondary total hip arthroplasty at a median of 2.4 (0.1–14.1) years after an operatively treated acetabular fracture. The median age was 54 (11–82) years. Cemented arthroplasty was used for 33 patients, 10 patients had an uncemented arthroplasty and 9 patients received a hybrid arthroplasty. Average follow up was 8.0 (SD 5.0) years.ResultsTen-year revision free arthroplasty survival was 79%. Uncemented arthroplasties had a significantly worse 10-year survival of 57%. Arthroplasties performed at a centre without a pelvic fracture service also had a significantly worse 10-years survival of 51%. Cox regression showed similar results with an 8-fold increase in risk of revision for both uncemented arthroplasties and operations performed at a non-pelvic trauma centre.ConclusionTotal hip arthroplasty secondary to an operatively treated acetabular fracture provides good symptomatic relief. These patients are, however, complex cases and are probably best treated at specialist centres with both pelvic trauma surgeons and arthroplasty surgeons proficient in complex revisions present.     

No effect of low-dose aspirin for the prevention of heterotopic bone formation after total hip replacement: A randomized trial of 2,649 patients

2,649 patients scheduled for elective total hip replacement were recruited to the Heterotopic Bone Formation Sub-study of the Pulmonary Embolism Prevention Trial. Heterotopic bone formation was determined by radiographic examination and associated late postoperative outcomes were assessed by telephone interview. Heterotopic bone formation was observed in 627 (31%) of 2,048 radiographic examinations. There was no detectable effect of low-dose aspirin on the risks of heterotopic bone formation (RR 0.98; 95%CI 0.85-1.12), late postoperative pain (RR 1.10; 95%CI 0.91-1.35) or late postoperative impaired function (RR 1.03; 95%CI 0.94-1.12). The balance of benefits and risks of low-dose aspirin is determined by its effects on vascular events and bleeding, since it has no major effects on heterotopic bone formation or associated clinical outcomes.     

Arthrography for the diagnosis of abductor avulsion after total hip arthroplasty: A comparison of arthrographic and surgical findings in 33 patients

Background?Weakness of the abductor muscles—or even their avulsion—is a potential risk when total hip arthroplasty (THA) is performed using the anterolateral approach. Avulsion of the re-attached gluteus medius leads to a limp, but can also provide an open canal for joint fluid to escape to the trochanteric region. Thus, our hypothesis was that arthrography can be used to diagnose such detachment.

Methods?We compared THA arthrographies with peroperative findings retrospectively in 33 patients who had undergone surgical exploration for a muscle reattachment because of a strong suspicion of abductor avulsion at physical examination.

Results?After a mean follow-up time of 22 (2–57) months after THA, 14/33 patients had a positive (pathological) arthrogram whereas 19 had a negative (normal) result. All 14 patients with a positive arthrogram were verified to have an avulsion of the abductor muscle at the operation. 10 of the 19 patients with a negative arthrogram had an intact abductor insertion, but 9 had an avulsion. All of these 9 patients with the peroperatively disclosed avulsion had a fibrous capsule, which obstructed the fistula leading from the joint cavity to the trochanteric bursa region.

Interpretation?Arthrography is a valuable diagnostic aid in the evaluation of patients with abductor weakness and with Trendelenburg’s gait appearing after a THA performed using the anterolateral approach. A positive finding helps in the operative decision making, but a negative arthrogram is not a reliable predictor.     

Low revision rate after total hip arthroplasty in patients with pediatric hip diseases

Background The results of primary total hip arthroplasties (THAs) after pediatric hip diseases such as developmental dysplasia of the hip (DDH), slipped capital femoral epiphysis (SCFE), or Perthes’ disease have been reported to be inferior to the results after primary osteoarthritis of the hip (OA).

Materials and methods We compared the survival of primary THAs performed during the period 1995–2009 due to previous DDH, SCFE, Perthes’ disease, or primary OA, using merged individual-based data from the Danish, Norwegian, and Swedish arthroplasty registers, called the Nordic Arthroplasty Register Association (NARA). Cox multiple regression, with adjustment for age, sex, and type of fixation of the prosthesis was used to calculate the survival of the prostheses and the relative revision risks.

Results 370,630 primary THAs were reported to these national registers for 1995–2009. Of these, 14,403 THAs (3.9%) were operated due to pediatric hip diseases (3.1% for Denmark, 8.8% for Norway, and 1.9% for Sweden) and 288,435 THAs (77.8%) were operated due to OA. Unadjusted 10-year Kaplan-Meier survival of THAs after pediatric hip diseases (94.7% survival) was inferior to that after OA (96.6% survival). Consequently, an increased risk of revision for hips with a previous pediatric hip disease was seen (risk ratio (RR) 1.4, 95% CI: 1.3–1.5). However, after adjustment for differences in sex and age of the patients, and in fixation of the prostheses, no difference in survival was found (93.6% after pediatric hip diseases and 93.8% after OA) (RR 1.0, CI: 1.0–1.1). Nevertheless, during the first 6 postoperative months more revisions were reported for THAs secondary to pediatric hip diseases (RR 1.2, CI: 1.0–1.5), mainly due to there being more revisions for dislocations (RR 1.8, CI: 1.4–2.3). Comparison between the different diagnosis groups showed that the overall risk of revision after DDH was higher than after OA (RR 1.1, CI: 1.0–1.2), whereas the combined group Perthes’ disease/SCFE did not have a significantly different risk of revision to that of OA (RR 0.9, CI: 0.7–1.0), but had a lower risk than after DDH (RR 0.8, CI: 0.7–1.0).

Interpretation After adjustment for differences in age, sex, and type of fixation of the prosthesis, no difference in risk of revision was found for primary THAs performed due to pediatric hip diseases and those performed due to primary OA.     

氧化铝全陶界面在中青年患者全髋关节置换术中的临床中期结果

目的回顾分析第三代氧化铝陶瓷全髋关节置换在中青年患者中的中期临床疗效。方法回顾性收集2001年5月至2006年5月,本组98例行全陶人工髋关节置换术患者的临床资料,共获得有效随访患者82例,共89例髋,其中男43例（48髋）,女39例（41髋）,平均年龄47.6岁,平均随访时间101.9个月（66~120个月）,对有效随访的患者均进行临床和影像学检查评估疗效。结果患者术前Harris评分（49.8±8.0）分（36~65分）,术后末次随访（92.3±2.6）分（86~97分）（P〈0.05）。术后随访均未见假体破裂,未发生假体周围感染,无翻修病例。1例术后出现脱位,1例出现关节异响现象,均在非手术治疗后消失。术后影像学均无可观察到的磨损和骨溶解,无明显异位骨化,无假体松动。结论本研究结果显示,第三代氧化铝全陶髋关节假体用于中青年患者初次全髋关节置换术,中期临床随访结果满意,是一种良好的手术选择。     

Approaches to objective assessment of the individual weight bearing in patients after total endoprosthesis of the hip joint

An algorithm for the detection of weight bearing on the lower extremity after total endoprosthesis of the hip joint was developed, taking into consideration the parameters of the morphometric structure, type of pathology, method of treatment, the resulting extremity functioning and social and every-day conditions. The individual rehabilitation measures after endoprosthesis were performed in three steps and corrected depending on changes in the parameters in question. The amplitude of movements in the joint after using the method of calculation of the weight bearing on the lower extremity became close to normal in 26 patients after completion of the rehabilitation course and the statistic-dynamic indices of the extremity became stable.     

The effect of partial or full weight bearing ambulation after cementless total hip arthroplasty

The clinical and radiographic results of 46 patients who underwent 50 consecutive primary total hip arthroplasties using a fully porous-coated collared femoral component were determined at a minimum of 2 years' follow-up. Twenty-four patients (25 hips) who were allowed to bear full weight immediately postoperatively were compared with a historical control group of 24 patients (25 hips) who were instructed to bear < or =50 lb of weight for 6 weeks. The average Harris hip score for the partial weight bearing group was 95 compared with 97 for the full weight bearing group. All femoral components in both groups had radiographic evidence of bone ingrowth fixation at the final follow-up. When solid initial fixation is obtained intraoperatively and radiographically using a fully porous-coated (AML) femoral component, it seems that bone ingrowth fixation reliably occurs whether or not a partial or full weight-bearing postoperative protocol is followed.