Preoperative lateral subluxation of the patella is a predictor of poor early outcome of Oxford phase-III medial unicompartmental knee arthroplasty

Background and purpose

There is disagreement in the literature about the importance of patellofemoral joint degeneration and knee pain for the outcome of unicompartmental knee arthroplasty (UKA). We therefore investigated the importance of selected predictors including patellofemoral joint degeneration and the location of preoperative knee pain for the early outcome of UKA.

Patients and methods

The study group comprised 260 consecutive patients from 5 hospitals who underwent Oxford UKA for anteromedial osteoarthritis. Data were collected at baseline and included pain location, radiologically observed degeneration of the patellofemoral joint including subluxation of the patella, intraoperative cartilage status of the patellofemoral joint, disease-specific knee status, and Oxford knee score (OKS). Outcomes were evaluated after 1 year using the OKS, global patient satisfaction, and global patient result.

Results

The average OKS score at baseline was 24 (SD 7), and it was 40 (SD 8) at the 1-year follow-up. 94% of the patients claimed improvement after the operation and 90% were satisfied with the UKA. Lateral subluxation of the patella was a predictor of poor outcome, and the preoperative OKS score was also a predictor of outcome. Full-thickness cartilage loss at any location gave a similar outcome to that with a normal or near-normal joint surface, and likewise, preoperative anterior knee pain was not a predictor of outcome.

Interpretation

We conclude that the good early outcome after UKA in this study is in line with the best reported results. Patellofemoral degeneration should not be considered a contraindication to Oxford UKA. Patients with lateral subluxation of the patella have an increased risk of a poor result after UKA and should preferably be offered a total knee replacement.There is no consensus about the indications for choosing unicompartmental knee arthroplasty (UKA) instead of total knee arthroplasty. Kozinn and Scott (1989) accepted only minor degenerative changes in the patellofemoral joint, and anterior knee pain—thought to be a sign of significant patellofemoral involvement—has also been an exclusion criterion (Stern et al. 1993). Berger et al. (2004) stated that patients with clinical, radiographic, or intraoperative evidence of patellofemoral arthrosis are not appropriate candidates for unicompartmental knee arthroplasty. However, the Oxford Group recommended that the state of the patellofemoral joint should be ignored when deciding whether or not to use UKA (Goodfellow et al. 1986, 2006). A recent paper by the Oxford group (Beard et al. 2007a) demonstrated that anterior knee pain or damage to the patellofemoral joint (provided that there is not bone loss and grooving of the lateral facet) is not a contraindication for Oxford UKA, while caution should be observed in cases with lateral patellofemoral joint degeneration. In these cases, a TKR should be preferred to avoid clinical failure.Here we describe early outcome after Oxford phase-III UKA. We also investigated the importance of selected predictors—including patellofemoral joint degeneration, subluxation of the patella, and the location of preoperative knee pain—for early outcome.     

髌股关节软骨损伤对Oxford单髁置换术的疗效研究

目的探讨单髁置换术对膝前内侧骨关节炎合并髌股关节软骨损伤患者术后疗效的影响。方法选择自2016年3月至2018年8月期间,山西医科大学附属人民医院骨科关节微创病区完成的单髁置换病例67例,均因为膝前内侧骨关节炎就诊,所有病例均为单侧膝关节置换。其中男19例,女48例;年龄51~84岁,平均(64.67±8.37)岁;左膝41例,右膝26例;身体质量指数(body mass index,BMI)19.56~30.47kg/m 2,平均(25.27±2.56)kg/m 2;病程为0.5~20.0年,平均(5.08±4.83)年。术中通过Outerbridge分级记录观察到的髌股关节软骨损伤并进行分组,术后随访通过牛津膝关节评分(oxford knee score,OKS)、Lonner髌股关节评分评价术后疗效、髌股关节疼痛及功能改善情况,对术前及术后随访的评分分别进行统计学分析,以P<0.05为差异有统计学意义。结果所有患者均完成随访,随访时间12~25个月,平均(18.12±3.68)个月;OKS评分由术前平均(44.42±4.86)分降低至术后平均(21.46±4.64)分(P<0.01);Lonner疼痛评分由术前平均(29.91±2.48)分提高至术后平均(49.54±2.42)分(P<0.01);Lonner功能评分由术前平均(23.17±1.40)分提高至术后平均(38.89±1.41分)(P<0.01)。术中观察发现35膝(52%)合并内侧髌股关节软骨损伤病例,与无髌股关节软骨损伤病例(32膝)相比,术后髌股关节疼痛感及功能均得到改善,术后1、3、6、12个月OKS评分、Lonner疼痛与功能评分对比,差异均无统计学意义(P>0.05)。结论术中证实的内侧髌股关节软骨损伤并不影响Oxford单髁置换术短期疗效。单髁置换术可作为合并内侧髌股关节软骨损伤的膝前内侧骨关节炎患者的治疗方式。     

髌股关节软骨退变程度对单髁置换术后效果的影响

目的探讨髌股关节软骨退变程度对内侧活动平台单髁置换术短期疗效的影响。 方法回顾性分析2017年1月至2018年12月在深圳市人民医院因前内侧骨关节炎行内侧活动平台单髁置换或全膝关节置换术的75例患者资料,依据术中探查髌股关节软骨退变情况分为无退变单髁组(无退变组)、内侧退变单髁组(内侧退变组)、内外退变单髁组(内外退变组)和内外退变全膝组(全膝组)。单因素方差分析对比4组患者术前术后牛津大学膝关节评分(OKS)、美国特种外科医院(HSS)评分、骨关节炎指数(WOMAC)评分,并记录终末随访时有无假体松动、脱位、力线改变等情况。 结果所有患者获得随访,随访时间平均(36±10)个月。4组患者术后OKS评分、HSS评分、WOMAC评分较术前均有改善(F＝18.555,P<0.001;F＝5.867,P＝0.001;F＝22.671,P<0.001);术前术后OKS、HSS、WOMAC评分差值,无退变组与内侧退变组之间差异均无统计学意义(均为P>0.05),内外退变组与无退变组、内侧退变组相比,功能改善程度稍差(均为P<0.05),内外退变组与全膝组之间OKS、HSS、WOMAC评分差值差异无统计学意义(均为P>0.05)。所有病例于末次随访时无假体松动、脱位、力线改变。 结论内侧髌股关节软骨退变对内侧活动平台单髁置换术后疗效影响不大,但面对外侧髌股关节软骨退变时则需慎重,此时选择单髁或是全膝,需个性化考虑。     

Pre-operative clinical and radiological assessment of the patellofemoral joint in unicompartmental knee replacement and its influence on outcome

Anterior knee pain and/or radiological evidence of degeneration of the patellofemoral joint are considered to be contraindications to unicompartmental knee replacement. The aim of this study was to determine whether this is the case. Between January 2000 and September 2003, in 100 knees (91 patients) in which Oxford unicompartmental knee replacements were undertaken for anteromedial osteoarthritis, pre-operative anterior knee pain and the radiological status of the patellofemoral joint were defined using the Altman and Ahlback systems. Outcome was evaluated at two years with the Oxford knee score and the American Knee Society score. Pre-operatively 54 knees (54%) had anterior knee pain. The clinical outcome was independent of the presence or absence of pre-operative anterior knee pain. Degenerative changes of the patellofemoral joint were seen in 54 patients (54%) on the skyline radiographs, including ten knees (10%) with joint space obliteration. Patients with medial patellofemoral degeneration had a similar outcome to those without. For some outcome measures patients with lateral patellofemoral degeneration had a worse score than those without, but these patients still had a good outcome, with a mean Oxford knee score of 37.6 (SD 9.5). These results show that neither anterior knee pain nor radiologically-demonstrated medial patellofemoral joint degeneration should be considered a contraindication to Oxford unicompartmental knee replacement. With lateral patellofemoral degeneration the situation is less well defined and caution should be observed.     

腘绳肌腱移植包埋法重建内侧髌股韧带治疗复发性髌骨脱位

目的 :探讨腘绳肌腱移植包埋法重建内侧髌股韧带治疗复发性髌骨脱位的疗效。方法 :2008年3月至2013年6月间收治复发性髌骨脱位67例,其中男28例,女39例;年龄10~42岁,平均22岁。临床表现为膝关节不稳感,"打软腿",髌骨错位感,膝前疼痛等。67例均行腘绳肌腱移植包埋法重建内侧髌股韧带。术前后采用Lysholm评分及Q角变化对疗效进行评估。结果:术后67例均获随访,随访时间4~60个月,平均(27.5±13.4)个月。术后切口均愈合良好,无髌骨脱位或半脱位发生。Lysholm评分由术前76.35±2.86提高到术后82.71±2.29;Q角从术前(18.75±2.33)°降至术后(13.28±1.75)°。结论:腘绳肌腱移植包埋方法重建内侧髌股韧带可以提供足够的张力,恢复髌骨稳定性,改善膝关节功能。     

髌股关节置换术治疗单纯髌股关节炎的疗效研究

目的:探讨髌股关节置换术治疗单纯髌股关节炎的临床疗效。方法:2013年7月至2017年6月行髌股关节置换术患者35例42膝,女34例,男1例;年龄45~70(55.0±8.2)岁;病程6~36(13.7±2.5)个月。术前及末次随访时对患者进行牛津膝关节评分,末次随访时对患者进行手术满意度评估,另摄膝关节正侧位X线片及髌骨轴位片,评估有无假体松动,记录患者术后出现的血肿、关节感染等并发症。结果:35例患者42膝随访时间18~65(35.0±7.2)个月,手术时间(56.2±8.7)min。牛津膝关节评分由术前(28.14±0.36)分提高至术后末次随访(37.19±0.47)分,差异有统计学意义(P<0.05),其中疼痛项目评分由术前(10.12±0.26)分提高至术后末次随访(15.83±0.30)分,功能项目评分由术前(18.02±0.13)分提高至术后末次随访(21.36±0.23)分,差异均有统计学意义(P<0.05)。有1例患者双膝术后早期出现伤口线结反应,经清创后好转;另1例术后5周出现伤口周围红肿,经抗生素治疗后好转;1例术后1个月出现股四头肌缝合处撕裂,经重新缝合后好转;未发现假体松动者。结论:第2代假体髌股关节置换术治疗单纯严重髌股关节炎早期临床疗效满意,并发症少,但应严格把握手术指征,严重病例可选用膝关节CT扫描定制髌股关节假体,减少术后并发症,提高临床疗效。     

Einfluss der Retropatellararthrose auf das funktionelle Ergebnis nach unikondylären Schlittenprothesen

Background

Patellofemoral osteoarthritis is generally considered a contraindication for unicondylar knee arthroplasty. Therefore, even with an intact lateral compartment, bicondylar surface replacement is preferred when patellofemoral osteoarthritis is present, despite comparatively worse functional results. In the present study, the influence of patellofemoral osteoarthritis on the outcome of the Oxford III unicondylar implant was investigated.

Material and methods

The HSS and the patella score according to Turba were used to retrospectively evaluate the outcome of 44 Oxford III unicondylar implants at an average follow-up of 35 months. The degree of patellofemoral osteoarthritis was radiographically graded according to the Sperner score.

Results

The HSS score improved to an average of 92.3 points (68–99; p<0.001 vs preoperative score). With the patella score, only good and very good results were observed. At follow-up examination almost 70% of the knees showed patellofemoral osteoarthritis of degree III–IV. No correlation was found between the functional scores and the degree of patellofemoral osteoarthritis.

Conclusion

Radiographic patellofemoral osteoarthritis seems to have no influence on the functional outcome of the Oxford III unicondylar knee arthroplasty. Therefore, unicondylar surface replacement is indicated even with radiographic evidence of patellofemoral osteoarthritis, provided that it is clinically asymptomatic.     

A Weighted Scoring System Based on Preoperative and Long-Term Patient-Reported Outcome Measures to Guide Timing of Knee Arthroplasty

BackgroundThere is currently no existing consensus regarding timing of knee arthroplasty. This study aimed to develop a weighted scoring system from patient-reported outcome measures (PROMs) to guide timing of knee arthroplasty based on preoperative severity and long-term effectiveness.MethodsProspectively collected data of 766 total knee arthroplasties (TKAs) and 382 unicompartmental knee arthroplasties (UKAs) at a single institution were analyzed. PROMs were assessed preoperatively and at 10 years using the Knee Society Score (KSS), Oxford Knee Score (OKS), and Short Form-36 physical component score (SF-36 PCS). Receiver operating characteristic analysis identified thresholds where preoperative PROMs predicted 10-year clinically meaningful improvements (minimal clinically important difference [MCID]). Threshold weights were assigned to PROMs based on their ability to predict MCID in isolation or in combination.ResultsPoorer baseline PROMs predicted 10-year MCID attainments. The threshold of 49.5 points for the KSS, 30.5 points for the OKS, and 40.7 points for the SF-36 PCS and 55.5 points for the KSS, 33.5 points for the OKS, and 40.5 points for the SF-36 PCS was weighted 1 point for predicting MCID in 1 PROM for TKA and UKA, respectively. The threshold of 33.4 and 33.9 points for the SF-36 PCS was weighted 2 points for predicting MCID in 2 PROMs, whereas 29.3 and 31.3 points for the SF-36 PCS were weighted 3 points for predicting MCID in 3 PROMs for TKA and UKA, respectively. The sum of weighted components from 0 (lowest) to 5 (highest) represented likelihood for long-term benefits at 10 years.ConclusionThis scoring system is a useful clinical adjunct for deciding timing of knee arthroplasty and prioritizing patients in institutions with long waitlists.Level of EvidenceII.     

Anterior Cruciate Ligament Deficiency is Not Always a Contraindication for Medial Unicompartmental Knee Arthroplasty: A Retrospective Study in Nondesigner’s Japanese Hospital

BackgroundAn intact anterior cruciate ligament (ACL) is thought to be prerequisite for successful unicompartmental knee arthroplasty (UKA), but recent studies reported successful midterm results of UKA in ACL-deficient (ACLD) knees. We hypothesized that ACLD is not always a contraindication for medial UKA when preoperative radiographs showed typical anteromedial knee patterns.MethodsFrom April 2012 to March 2016, 401 Oxford mobile-bearing UKAs in 282 patients were retrospectively identified from our database. Patients whose ACL was severely damaged, but preoperative X-rays showed typical anteromedial osteoarthritis patterns, were categorized into the ACLD group. From intraoperative data, those whose ACL was intact were categorized into the ACL functional (ACLF) group. There were 32 and 369 knees in the ACLD and ACLF groups, respectively, and mean follow-up periods were 66.1 and 63.8 months for the ACLD and ACLF groups, respectively. We compared the postoperative clinical outcome and component survivorship, with an endpoint of component revision, between ACLD groups and ACLF groups.ResultsIn both groups, the Oxford knee score, Knee Society score, Tegner activity score, and knee range of motion in extension were improved after surgery. The UKA component survival rate at five years was 100% in the ACLD group and 98.9% in the ACLF group. There were no significant differences between the groups.ConclusionMid-term clinical outcomes of Oxford mobile-bearing UKA in ACLD knees were similar to those in ACLF knees. ACL deficiency is not always a contraindication for medial unicompartmental knee arthroplasty in patients with typical anteromedial osteoarthritis radiographs.     

Does preoperative patellofemoral joint state affect medial unicompartmental arthroplasty survival?

One contested contraindication to medial unicompartmental knee arthroplasty (UKA) has been status of the patellofemoral joint. Surgeons have avoided UKA when the patellofemoral joint has radiographic evidence of arthritic changes. However, recent studies advocate ignoring patellofemoral joint status when considering UKA. The purpose of this study was to compare the failure rate of mobile-bearing, medial UKA in patients with and without preoperative radiographic evidence of patellofemoral joint degeneration. Preoperative radiographs from a random selection of 503 patients (638 knees) treated with UKA for anteromedial osteoarthritis were assessed by an observer blinded to clinical outcome. The patellofemoral joint was graded using the modified Altman classification from 0 to 3 with 0 being no evidence of changes and 3 being severe, and identified 396 grade 0, 168 grade 1, 65 grade 2, and 9 grade 3 knees. At 1- to 7-year follow-up, there have been 17 revisions for overall survivorship of 97.3%. Kaplan-Meier analysis predicted 97.9% survival in knees with patellofemoral joint disease and 93.8% survival in knees without patellofemoral joint disease at 70 months (P=.1). Failure requiring revision occurred in 3.5% (14/396) of grade 0 knees, 1.2% (2/168) of grade 1, 1.5% (1/65) of grade 2, and 0% (0/9) of grade 3. No survival difference was noted between knees with medial or lateral patellofemoral joint disease (P=.1). No knees were revised for progression of disease in the patellofemoral joint or anterior knee pain. In light of this investigation and the work of others, preoperative radiographic changes in the patellofemoral joint can be safely ignored when considering patients for medial UKA without compromising survivorship.     

髌股关节退变对Oxford内侧单髁置换疗效的影响

目的本研究对因膝关节前内侧关节炎进行Oxford单髁置换的中国患者前瞻性收集数据和术中观察髌股关节情况,并探讨这一结论的正确性。方法研究包括本单位从2009年8月至2011年5月连续进行的50例（45例患者）单髁置换病例。术前记录膝关节疼痛的部位,放射学检查发现的髌股关节退变用Ahlback系统分级。对于术中观察到的股骨滑车软骨磨损情况用Weidow5级分级系统记录,其将软骨状况从无磨损到全层磨损分为0至Ⅳ级。在术后1年随访是用Hospitalfor Special Surgery膝关节评分系统和自我满意度评分对临床疗效进行评定。结果术前放射学检查发现17膝（34％）存在髌股关节退变。术中观察发现27膝（54％）存在股骨滑车软骨面磨损,其中19例（38％）位于滑车沟偏内侧,6例（12％）位于滑车沟中央,1例（2％）位于滑车沟偏外侧,共有3例（6％）全层软骨磨损,2例（4％）位于滑车沟偏内侧,1例（2％）位于滑车沟偏外侧。不论是放射学发现的髌股关节退变还是术中发现软骨磨损病例与髌股关节相对正常病例相比,临床疗效没有显著性差异。结论术前放射学发现的髌股关节退变和术中发现髌股关节软骨磨损均不能作为Oxford内侧单髁置换的反指征。因外侧髌股关节退变的相关数据较少,对这类患者选择单髁置换时应慎重。     

Influence of patellofemoral osteoarthritis on functional outcome after unicondylar knee arthroplasty

BACKGROUND: Patellofemoral osteoarthritis is generally considered a contraindication for unicondylar knee arthroplasty. Therefore, even with an intact lateral compartment, bicondylar surface replacement is preferred when patellofemoral osteoarthritis is present, despite comparatively worse functional results. In the present study, the influence of patellofemoral osteoarthritis on the outcome of the Oxford III unicondylar implant was investigated. MATERIAL AND METHODS: The HSS and the patella score according to Turba were used to retrospectively evaluate the outcome of 44 Oxford III unicondylar implants at an average follow-up of 35 months. The degree of patellofemoral osteoarthritis was radiographically graded according to the Sperner score. RESULTS: The HSS score improved to an average of 92.3 points (68-99; p<0.001 vs preoperative score). With the patella score, only good and very good results were observed. At follow-up examination almost 70% of the knees showed patellofemoral osteoarthritis of degree III-IV. No correlation was found between the functional scores and the degree of patellofemoral osteoarthritis. CONCLUSION: Radiographic patellofemoral osteoarthritis seems to have no influence on the functional outcome of the Oxford III unicondylar knee arthroplasty. Therefore, unicondylar surface replacement is indicated even with radiographic evidence of patellofemoral osteoarthritis, provided that it is clinically asymptomatic.     

Valgus Subsidence of the Tibial Component Caused by Tibial Component Malpositioning in Cementless Oxford Mobile-Bearing Unicompartmental Knee Arthroplasty

BackgroundValgus subsidence (VS) of the tibial component is a rare complication of unicompartmental knee arthroplasty (UKA), and surgeons might consider revision surgery. The present study aimed to identify the factors related to VS of the tibial component after cementless Oxford mobile-bearing UKA.MethodsThe study included 120 patients who underwent Oxford mobile-bearing UKA using a cementless tibial component in our center between September 2015 and September 2016. Six showed VS of >2° after surgery. Patients were stratified into 2 groups according to the occurrence of VS of the tibial component (VS group, n = 6; no-subsidence group, n = 114). Postoperative radiographic evaluations were conducted to assess the varus/valgus alignment, rotation, and mediolateral position of the tibial and femoral components. The Oxford Knee Score (OKS) was assessed at 3, 6, and 12 months postoperatively. Positional parameters and sequential change in OKS were compared between the two groups using unpaired t-test (P < .05, statistically significant).ResultsAt 3 months postoperatively, an average VS of 3.4° in the VS group was observed, with a significant decrease in OKS. VS was associated with a significantly more medial position and external rotation of the tibial component. After 3 months, VS stopped, and the OKS gradually improved without revision surgery.ConclusionsVS might be caused by the malpositioning of the tibial component. VS of the tibial component after UKA appears to stop, with simultaneous pain relief, even without revision after 3 months postoperatively.     

The influence of the presence and severity of pre-existing patellofemoral degenerative changes on the outcome of the Oxford medial unicompartmental knee replacement

Patellofemoral joint degeneration is often considered a contraindication to medial unicompartmental knee replacement. We examined the validity of this preconception using information gathered prospectively on the intra-operative status of the patellofemoral joint in 824 knees in 793 consecutive patients who underwent Oxford unicondylar knee replacement for anteromedial osteoarthritis. All operations were performed between January 1998 and September 2005. A five-point grading system classified degeneration of the patellofemoral joint from none to full-thickness cartilage loss. A subclassification of the presence or absence of any full-thickness cartilage loss was subsequently performed to test selected hypotheses. Outcome was evaluated independently by physiotherapists using the Oxford and the American Knee Society Scores with a minimum follow-up of one year. Full-thickness cartilage loss on the trochlear surface was observed in 100 of 785 knees (13%), on the medial facet of the patella in 69 of 782 knees (9%) and on the lateral facet in 29 of 784 knees (4%). Full-thickness cartilage loss at any location was seen in 128 knees (16%) and did not produce a significantly worse outcome than those with a normal or near-normal joint surface. The severity of the degeneration at any of the intra-articular locations also had no influence on outcome. We concluded that, provided there is not bone loss and grooving of the lateral facet, damage to the articular cartilage of the patellofemoral joint to the extent of full-thickness cartilage loss is not a contraindication to the Oxford mobile-bearing unicompartmental knee replacement.     

Erfahrungen mit medialen monokondylären Prothesen mit mobilem Plateau

Background

Unicompartmental knee arthroplasty (UKA) has become an accepted therapy for medial osteoarthritis. The main reasons for its popularity are the minimally invasive surgical technique and the reports of excellent long-term results including high patient satisfaction and good knee joint function especially in younger patients.

Objectives

The purpose of our retrospective study was to evaluate the physical activities of patients who had undergone an Oxford III medial UKA. Special attention was paid to implant positioning and osteoarthritis of the patellofemoral joint.

Materials and methods

Of 181 implanted Oxford III prosthesis, 136 (75.1%) could be followed up. The mean age at time of surgery was 65.2 years; the average time of follow-up was 4.2 years. In addition to a physical examination and x-ray, the following scores were obtained: WOMAC (Western Ontario and McMaster Osteoarthritis Index), OKS (Oxford Knee Score), KSS (Knee Society Score), UCLA activity and the Turba score.

Results

The majority of the patients (81%) returned to their sporting activity following knee surgery. Higher complication rates or progression of osteoarthritis associated with sporting activities were not observed. The active patients had significantly higher scores for the OKS, KSS, WOMAC, and UCLA scores. The correct implant position, especially avoiding overcorrection to valgus malalignment, is important for good clinical outcome.

Conclusion

Our results demonstrate that a high degree of patient satisfaction in terms of physical and sporting activity can be achieved using the Oxford III UKA for medial osteoarthritis without an increased risk for complications.     

Reduced Bearing Excursion After Mobile-Bearing Unicompartmental Knee Arthroplasty is Associated With Poor Functional Outcomes

Background

A small proportion of patients with mobile unicompartmental knee arthroplasty (UKA) report poor functional outcomes in spite of optimal component alignment on postoperative radiographs. The purpose of this study is to assess whether there is a correlation between functional outcome and knee kinematics.

Evaluating Patients' Expectations From a Novel Patient-Centered Perspective Predicts Knee Arthroplasty Outcome

Background

One-in-five patients are dissatisfied following knee arthroplasty and <50% have fulfilled expectations. The relationship between knee-arthroplasty expectations and surgical outcome remains unclear.

牛津人工单髁关节置换假体生存分析及并发症处理策略

目的通过分析牛津3期活动平台人工单髁关节置换假体生存率,探讨其中长期临床疗效以及相关并发症的处理原则和预防策略。 方法选择自2007年4月至2016年10月期间,济南军区总医院骨病科应用人工单髁关节置换手术患者共435例515膝,均系膝关节前内侧骨关节病,其中男150例,女285例;年龄45～83岁,平均(61±8)岁。身体质量指数19～36 kg/m^2,平均(24±3)kg/m²。记录手术前后膝关节活动度(ROM)变化,采用美国膝关节协会评分(KSS评分)与牛津大学膝关节评分(OKS评分)评估临床疗效,记录术后所有并发症发生情况;采用Kaplan-Meier生存分析方法评估患者的假体生存率,对术前及末次随访的ROM变化、KSS评分、OKS评分分别进行配对t检验,以P<0.05为差异有统计学意义。 结果435例515膝全部完成随访,平均(5.2±1.8)年。至末次随访时,KSS评分由术前平均(59±10),改善至术后平均(93±8)(t＝－2.586,P<0.05);OKS评分由术前平均(24±8),提高至术后平均(43±5)(t ＝－2.056,P <0.05);膝关节术前平均(111±5)°,术后ROM平均(127±8)°(t ＝－2.334,P <0.05)。所有患者人工单髁关节假体总生存率为92.2%。515膝单髁关节中共有15例(2.9%)并发症发生,其中聚乙烯活动半月板衬垫脱位6例(1.2%);迟发性深部感染1例(0.2%),经规范抗感染治疗无效后行二期全膝关节翻修术,术后正常恢复;3例出现股骨髁侧假体松动(0.6%,含1例同时衬垫脱位病例),其中2例进行单髁关节翻修,1例予以全膝关节翻修;2例患者出现关节囊反复无菌性积液(0.4%),予以关节抽液并物理治疗后恢复;2例术后出现关节内游离体(0.4%),行关节镜手术取出后绞索症状消失;1例术后膝关节不明原因疼痛(0.2%),保守治疗后恢复;1例术中前交叉韧带止点部分撕脱(0.2%),术中予以韧带线缝合固定,术后铰链支具固定41周后功能锻炼,膝关节功能恢复良好。 结论牛津3期活动平台人工单髁关节置换是治疗膝内侧骨关节病的最佳治疗方法,临床疗效可靠,相关并发症发生率低;正确的适应证选择及成熟的外科操作能够保证UKA获得良好效果,降低并发症发生率;并发症的治疗需仔细分析发生的原因和类型,给予适当的处理。     

Design,operative technique and ten-year results of the Hermes™ patellofemoral arthroplasty

Purpose

Recently, increased interest has developed for patellofemoral arthroplasty as treatment for isolated patellofemoral arthritis. However, there are very few reports of the experience with the modern generation of patellofemoral arthroplasties. The new patellofemoral arthroplasty Hermes design is described. The design and technique of insertion are detailed.

Methods

The indications were isolated patellofemoral disease with advanced arthritic damage. Ten-year followup is available for treatment of 70 knees. Postoperative radiographs of patients were assessed for Oxford deterioration and maltracking of the patella. Tracking was categorised as follows: normal tracking, patellar subluxation, patellar dislocation.

Results

There were no late complications attributable to the arthroplasty. Disease progression in the tibiofemoral joint occurred in five patients requiring revision in three of these patients. Persistent anterior knee pain was recorded in four knees. The long-term results using this new design were better than those in the literature that described earlier designs, especially concerning malalignment. Only four knees in four patients had slight lateral patellar subluxation.

Conclusions

This implant offers a reasonable alternative to total knee replacement in patients with isolated patellofemoral disease.     

Early recovery after fast-track Oxford unicompartmental knee arthroplasty. 35 patients with minimal invasive surgery

Background and purpose

After total knee arthroplasty with conventional surgical approach, more than half of the quadriceps extension strength is lost in the first postoperative month. Unicompartmental knee arthroplasty (UKA) operated with minimally invasive surgery (MIS) results in less operative trauma. We investigated changes in leg-extension power (LEP) in the first month after MIS Oxford UKA and its relation to pain, knee motion, functional performance, and knee function.

Patients and methods

In 35 consecutive Oxford UKA patients, LEP was measured 1 week before and 1 month after surgery together with knee motion, knee swelling, the 30-second chair-stand test, and Oxford knee score. Assessment of knee pain at rest and walking was done using a visual analog scale.

Results

30 patients were discharged on the day after surgery, and 5 on the second day after surgery. LEP and functional performance reached the preoperative level after 1 month. Only slight postoperative knee swelling was observed with rapid restoration of knee flexion and function. A high level of pain during the first postoperative night and day fell considerably thereafter. None of the patients needed physiotherapy supervision in the first month after discharge.

Interpretation

Fast-track MIS Oxford UKA with discharge on the day after surgery is safe and leads to early recovery of knee motion and strength even when no physiotherapy is used.After total knee arthroplasty (TKA), more than half of the preoperative quadriceps strength is lost in the first month after surgery (Mizner et al. 2005). TKA surgery with minimally invasive surgery (MIS) may lead to less postoperative pain, shorter length of stay in hospital, and greater knee flexion (Chen et al. 2006), and the MIS approach may result in better outcome with regard to maintaining extensor strength than the conventional surgical approach (Kim et al. 2010). In unicompartment knee arthrosis, the Oxford Group recommend unicompartmental knee arthroplasty (UKA) operated with MIS, since recovery is twice as fast as after the conventional approach and damage to the soft tissue of the joint is greatly diminished (Price et al. 2001). Althrough fast-track UKA with length of stay of about 1.5 days has been described (Reilly et al. 2005), there have been few reports on quadriceps strength after UKA (Mancher et al. 2002) and to our knowledge there have been no reports on early leg-extension power (LEP) after UKA.We studied changes in LEP within the first month after fast-track MIS Oxford Phase III medial UKA in relation to pain, knee motion, functional performance, knee function, and the need for physiotherapy after discharge.