髌骨表面置换术中髌骨骨床保留厚度的探讨

Thickness of patellar bony mattress preservation in patellar resurfacing arthroplasty in Chinese

目的探讨国人髌骨置换时髌骨骨床保留厚度及术后总厚度对手术效果的影响。方法自2000年5月～2001年6月,对188例293侧全膝关节置换患者术中测量髌骨最厚处、最薄处和髌骨截骨后保留骨床厚度以及安装髌骨假体后髌骨的总厚度,术后对患者进行随访,观察置换术后髌骨厚度对关节功能的影响。结果(1)截骨前髌骨厚度测量结果为(24.25±2.62)mm。(2)截骨后髌骨骨床测量结果:143膝为14mm(48.81%),26膝为13mm(8.87%),24膝为12mm(8.19%),3膝为11mm(1.02%),97膝在15mm以上(33.11%)。保留髌骨骨床厚度在15mm以下和15mm及15mm以上的病例组均未出现髌骨假体或髌骨并发症。(3)所有术后髌骨的厚度均等于或小于术前,其中185膝(63.14%)的髌骨厚度与术前相等,108膝(36.86%)的髌骨厚度小于术前,但相差不超过2mm,两组患者术后关节屈曲度、伸膝度及功能评分,差异无显著性意义(P>0.05)。结论(1)在国人全膝关节置换术中,保留12～14mm的髌骨骨床不会引起髌骨骨折。(2)国人髌骨置换术后的髌骨厚度不应大于术前的厚度,最好能保持一致,如髌骨条件不许可或假体不匹配,可适当减少髌骨的厚度,但与置换前相比不宜超过2mm。(3)应大力发展适合国人的假体,包括髌骨假体。

Objective To investigate the effect of the preservation of thickness of bony patellar mattress and postoperative total patellar thickness on the clinical result in patellar resurfacing arthrop lasty in Chinese adults.Methods From May 2000to June 2001,the maxima l and minimam thickness of the patella,the preserved thickness of bony patella after resurfacing and t otal thickness of patella after pate llar replacement in 293consecutive tota l knee arthroplasty were measured.T he relationship between the postop-erative patellar thickness and the f unction of the knee was also observed.This series of patients consisted o f 35males(49knees)and 153females(244knees),with an average age of 63.6years(range from 22to 85years).The preoperative diagnoses included of osteoarthritis(73%),rheumatoid arthritis(25%)and others(2%).Results1)The mean maximam thickness before re surfacing was(24.25±2.62)mm(18to 32mm);the mean minimam thickness before r esurfacing was(17.06±2.53)mm(10to 22mm).2)The data of preserved bony patellar thickness was 14mm in 143cases(48.81%),13mm in 26cases(8.87%),12mm in 24cases(8.19%),11mm in 3cases(1.02%),and the thickness in 97cases was more than 15mm(33.11%).Three cases that retained 11mm bony patella were diagnosed as rheumatoid arthritis.The patients including the groups of bony patella below 14mm and over 15mm had no patell ar complication or prosthesis complication.3)The patellar prosthesis that were used was typeⅠ(diameter 30mm,thickness 8mm)in 48cases(16.38%),typeⅡ(diameter 32mm,thickness 8mm)in 195(66.55%),typeⅢ(diameter 34mm,thickness 8mm)in 17(5.80%),typeⅣ(diameter 34mm,thickness 10mm)in 27(9.22%)and typeⅤ(diameter 36mm,thickness 10mm)in 6(2.04%).4)The thickness of postoperative pate lla was equal to preoperative in 185cases(63.14%)and less in 108cases(36.86%),however,there was a variance withi n2mm.No significant difference betw een two groups in ROM of knee and knee f unctional score(P>0.05)were found.No patellar fracture,in stability and patellar subluxation happened.Conclusion1)Retaining at least 15mm bony patella was reported by many authors,however this 15mm bony patella was not able to be obtained in nearly half of cases in Chinese people.In this clinical research,the thickness of retaining bony patella(12to 14mm)do not cause patellar fracture after total knee arthroplasty in Chinese a dults.2)Restoration of overall patellar thi ckness is most desirable following p atellar resurfacing,but if it is hard to do so;the overall patellar thickness c an be reduced,and preferrably never exceed 2mm.3)There are many types of prosthesis in Chinese market,but most of them are designed for Western people.There is seldom patellar prosthesis of small size available i n China,so it is urgent for us to develo p prosthesis to match Chinese people,including patellar prosthesis.