28 mm Metasul™ bearings in primary total hip arthroplasty

Assessment of possible low-wear with some former metal-on-metal (MoM) total hip arthroplasties (THA) led to the reintroduction of metallic bearings in the late 80’s. The author reports on two studies of Metasul-28 mm cementless THA. In the first one in a general population, impingement has been the main cause of osteolysis and Co level survey has been a good indicator of Metasul bearing behaviour. In the second study, in a group of 83 less than 50-year-old and active patients, Metasul bearings showed good wear resistance at 7.2 years mean follow-up. In both studies, no general toxic effect could have been detected thus far. According to the current knowledge, it is always reasonable to expect low-wear and better THA longevity with use of MoM bearings under the following conditions: 1) use of a CoCr alloy with high carbide concentration; 2) reduce impingement risk (head without sleeve, slimmer as possible neck, perfectly adapted Morse cone from the same manufacturer, well — oriented components); and 3) prefer cementless acetabular fixation.     

Cementless total hip arthroplasty in the treatment of severe hip dysplasia or dislocated hips

We present our experience over 6 years with the use of uncemented total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH) with a mean follow-up of 3 years. In a 6-year period, 26 THAs were performed in 19 patients with Hartofilakidis grades 2 and 3 dislocation of the hips. Out of 19 patients, seven had bilateral dislocations. Uncemented acetabular and femoral components were used in all patients. Patients with a minimum follow-up of 1 year were included in the study. The average age at the time of surgery was 38 (range 20–69) years. Approaches used include trochanteric osteotomy in 14 (54%) patients and a lateral approach in 12 (46%) patients. In addition, subtrochanteric osteotomy was performed in four (15%) patients. A Mallory-head femoral stem was used in 15 (58%) patients; a DDH femoral stem was in nine (35%), and the S-ROM femoral prosthesis in two (8%). A Mallory head acetabular shell was used in all cases, a 22.2-mm chrome cobalt head was used in 18 (69%), and a 28-mm chrome cobalt head was used in eight (31%). The average follow-up was 3 (range 1–6) years. The Harris hip score (HHS) improved in the cohort from a mean preoperative score of 51 to a mean postoperative score of 86 (p<0.05). The mean preoperative SF36v2 score was 42 compared to postoperatively of 67(p<0.05). The complication rate was 11% with nonunion of a subtrochanteric osteotomy in one patient, dislocation in one, and trochanteric bursitis due to fracture of Dall-Miles cables in one. THA for DDH is a technically demanding procedure. This short-term follow-up of THA for DDH using uncemented implants is encouraging for arthrosis secondary to DDH. It provides better function compared to arthrodesis or excision arthroplasty, especially in young individuals. A long-term follow-up is required in order to establish the role of this management strategy.     

隐性失血对双侧人工全膝关节同期置换手术的影响

[目的]研究双侧人工全膝关节同期置换术术后隐性失血的相关因素。[方法]对2005年2月～2007年2月44例双侧人工全膝关节同期置换术患者进行回顾性分析，通过Gross方程，根据身高、体重及手术前后的红细胞压积推算术后平均显性失血量及平均隐性失血量。[结果]平均总失血量2065ml，其中显性失血量1198ml，隐性失血量867ml，使用自体血回输患者总失血量为2180ml，隐性失血量为937ml（42％）；未使用自体血回输患者的总失血量是1950ml，隐性失血量是799ml（41％）；两组的隐性失血相比差异无统计学意义。[结论]双侧人工全膝关节同期置换术术后隐性失血量占总失血量的比例较高，且使用自体血回输不能完全满足机体恢复体循环的需要，在围手术期要特别注意及时补充血容量。     

80 例人工全髋关节置换术的中期疗效分析

目的 探讨人工全髋关节置换术的疗效。方法 回顾性研究了1997年3月至2002年12月期间连续全髋关节置换术80例(92髋)患者，平均随访54个月(14～84个月)，分析其中期疗效。结果 翻修率为5．4％(5／92)，Harris髋评分为优良以上84．8％(78／92)，中等8．7％(8／92)，差6．5％(6／92)。结论 外科技术的提高和假体生物工程的发展，提高了全髋关节置换术重建关节功能的疗效。     

Bone Mineral Density in the Proximal Femur and Contralateral Knee After Total Knee Arthroplasty

Osteoarthrosis (OA) is often associated with pain and disability, which are relieved after total knee arthroplasty (TKA), but the nature of bone changes associated with OA is controversial. We examined preoperative hip and contralateral knee bone mineral density (BMD) in patients requiring TKA and monitored the BMD changes postoperatively. Sixty-nine patients, scheduled to have TKA for osteoarthrotic knees, had both hips and contralateral knee BMD measured by dual-energy X-ray absorptiometry (DXA) at the time of operation (baseline) and at 1 yr after operation. X-rays of the knee joints were also taken to evaluate the severity of OA. Preoperatively, 27% and 38% of the patients had total hip BMD Z-score more than 1 SD in the operated side and contralateral hips, respectively. In all regions of interest (ROI), the mean baseline BMD of the affected side proximal femur was significantly lower than that of the contralateral side (p < 0.0005-0.019). The severity of OA was not associated with BMD. During 1-yr follow-up, the postoperative knee status and the physical activity of the patients (AKS score) improved. However, neither the hip nor the nonoperated knee BMDs increased. Knee OA is associated with significantly lower BMD values in the affected side compared with the contralateral hip, and these levels remained similar or decreased during a 1-yr follow-up. We conclude that improved mobility after TKA does not improve the effects of preoperative disuse-associated bone loss in the short term.     

Bone mineral density of the proximal tibia following uncemented arthroplasty

Bone mineral density (BMD, g/cm2) was measured using dual-photon absorptiometry (DPA) in selected areas of the proximal tibia following uncemented PCA knee prosthesis. In nine patients with 14 alloplastic operations, measurements were taken at 3-6-month intervals for the first 3 1/2 years after operation. There was a significant increase in BMD of about 15% during the first 6 months after operation. The following year it remained increased, although not significantly, compared with the initial values, then gradually diminished. Increased bone density after arthroplasty may be explained mainly by stimulation of bone formation from weight bearing due to improved walking ability. Stress shielding of the proximal part of the supporting tibial bone did not seem to occur.     

胫骨高位截骨对胫骨近端解剖形态的影响

[目的]测量胫骨高位截骨术后胫骨近端解剖形态,并与术前比较,探讨其变化的临床意义.[方法]2001～2005年,35例(59膝)因膝关节内侧室骨性关节炎接受胫骨高位截骨术患者的完整影像学资料,在术前、术后标准正侧位X线片中测量胫骨角;胫骨后倾角度;胫骨近端关节面外移;关节线高度.所得资料采用配对t检验进行统计学分析,以P＜0.01为差异有显著性意义.[结果]胫骨角术前平均为99.1°±4.3°,术后平均为91.1°±3.8°;胫骨后倾角度术前平均为8.9°±2.6°,术后平均为5.0°±2.3°;胫骨近端关节面外移术前平均为(46.2±3.6)%,术后平均为(53.1±3.9)%;关节线高度术前平均(41.2±3.6)mm,术后平均(38.0±3.2)mm.手术前后差异均有显著性意义(P＜0.01).[结论]胫骨近端解剖形态在胫骨高位截骨术后会发生明显变化,如胫骨角变小,后倾角度变小,胫骨近端关节面外移,关节线高度相对下降等,将对转行全膝关节置换术产生不良影响.     

Digital mucoid cyst excision by using the bilobed flap technique and arthroplastic resection

There are a number of proposed causes and treatment approaches for digital mucoid cysts. The described treatment outcomes for this cyst have been variable, with the highest success rate reported with complete excision and single-lobe skin flap closure. This report describes a bilobed flap reconstruction in conjunction with resection of the head of the middle phalanx. A retrospective review was undertaken to evaluate the recurrence rate, complications, and patient satisfaction with this combined procedure. Fifteen patients with an average follow-up of 4.6 years were evaluated. There were no recurrences, flap failures, or other major complications. The use of this flap allows for greater exposure than traditional semi-elliptical incisions while allowing the wide excisional defects to be closed primarily.     

Computerised and technical navigation in total knee-arthroplasty

Abstract The objective of the study was to evaluate the precision, concordance, practicability and the early clinical outcome of the use of a computerised navigation system in a comparative study with a group of 100 patients. Two groups of 50 patients each underwent implantation of a bicondylar knee prosthesis either by means of the freehand navigation system or by means of technical instrumentation. We found that the computerised navigation system provided a higher precision than the technically instrumented implantation: 94% of the prostheses implanted with the navigation system have an alignment within a range of -3° to 3° on of the Mikulicz line. Only 46% of the patients operated by means of the technical instrumentation reached this aspired result. Furthermore, the navigation system showed smaller ranges in the deviation of the aspired alignment. The radiological and computer-modeled alignment values differed both pre- and postoperatively, but to a larger extent before surgery. The varus or valgus deviations of the axis were more distinct radiologically under the weight of the patient’s body than in the computer model. The clinical outcome examined by the use of the HSS score after a mean followup of 7 months is good in both groups, and without significant differences. On average, the duration of surgery was 13 minutes longer in the computerised navigation group. We conclude that the benefit of the computerised navigation system is represented by the high improvement of precision. Achieving early clinical results identical to those in the technical instrumentation group, we expect a reduction of aseptic loosening in the computerised navigation group.     

Trapeziometacarpal joint osteoarthritis: a retrospective study comparing arthrodesis to tendon interposition arthroplasty

Abstract Surgical management of trapeziometacarpal joint osteoarthritis (OA) is still controversial. The aim of this study was to evaluate and compare results of trapeziometacarpal arthrodesis and of tendon interposition arthroplasty. One hundred twenty-six patients suffering from trapeziometacarpal OA underwent surgery between 1996 and 2001. Of these patients, 62 (78 thumbs) treated with joint arthrodesis and 33 (41 thumbs) treated with tendon interposition arthroplasty with abductor pollicis longus (APL) have been evaluated at follow-up and therefore entered this study. Mean age was 53 years, while the mean follow-up was 36 months. Overall results were satisfactory in 84 patients with good pain improvement. Patients treated with arthrodesis showed better functional ability in bi-digital pinch and grip strength. First finger opposition motion, however, was better conserved in patients treated with interposition arthroplasty. Fusions had an 11.5% complication rate (9 thumbs) with nonunions, whereas 14.8% (6 thumbs) of patients treated with interposition arthroplasty developed 1 first metacarpal base collapse, resulting in 1 first ray length reduction. Despite complications, however, patients did not report unsatisfactory results and generally experienced marked pain reduction. This study shows that arthrodesis can be considered the treatment of choice in patients suffering from trapeziometacarpal OA at Eaton stage III or less, whatever the age and when a good pinch strength is needed.