Präzise computergestützte Beinachsenkorrektur mit öffnender valgisierender Tibiakopfosteotomie

AIM: This prospective study investigates open-wedge high tibial osteotomy performed with the aid of a kinematic computer-guided navigation system. After the X-ray control the osteotomy was stabilized by internal LCP fixation. The aim of the study was to demonstrate the accuracy of the navigation system and to prove the reliability of the LCP fixation. METHOD: A total of 39 patients were operated between 2002 and 2003 following this method. The outcomes were evaluated at least 2 years after the surgery clinically and radiologically; 21 females (1 female underwent bilateral osteotomy) and 18 males were included in the study sample. RESULTS: Prior to the osteotomy, the mean anatomic lateral tibiofemoral angle (aLTFA) was 181.1 degrees . The desired 4 degrees "overcorrection" of valgus (aLTFA 170 degrees) was found on X-rays postoperatively in all cases. The mean correction was 11.1 degrees. The correction achieved was stable during the 2-year follow-up period. The osteotomy healed in all cases after 4 months. The full range of motion remained after the surgery in all cases. All patients were satisfied with their results. The Lysholm score was 55 points before and 82 points after the osteotomy (27 points difference). CONCLUSION: The computer-assisted open-wedge high tibial osteotomy with tricortical grafts stabilized by LCP fixation gives exact and reproducible results without loss of correction.     

改良内侧撑开楔形胫骨高位截骨矫正老年膝内翻的临床研究

目的探索高龄(>60岁)膝关节内侧骨关节炎并膝内翻畸形患者的手术技术及疗效。方法 2010年3月至2012年3月,采用改良内侧撑开楔形胫骨高位截骨矫正老年膝内翻畸形46例(52膝)。术前、后均拍患肢全长站立位X线片,测量髋(髋关节中心)-膝(膝关节中心)-踝(踝关节中心)形成的机械轴角度(HKA角),拍侧位X线片,测量胫骨平台后倾角,应用膝关节外科KOOS问卷评分标准对治疗后疗效评估。结果术后有32例(34膝)获随访,其余14例(18膝)因手术后不足3个月被排除在本组样本之外。32例随访时间为3～20个月,平均12.6个月。HKA角从术前(167.6°±3.7°)增加至术后平均(184.5°±1.2°)(P<0.05),胫骨平台后倾角术前平均(12.8°±1.3°),术后纠正到平均(9°±0.9°)(P<0.05);术后第2天带引流管直腿抬高、主动屈、伸膝关节锻炼;第3天,扶走步器负重行走;术后第7天生活已基本恢复自理;术后8～12周截骨端临床愈合。所有患者无一例感染、迟缓愈合、患肢无缺血及感觉障碍等并发症。疗效评估根据手术前、后的膝关节外科KOOS问卷评分结果,术前KOOS评分为(44.1±10.8)分,术后KOOS评分提高到(62.31±11.2)分,通过SPSS20统计学配对样本t检验确定其结果(P<0.05)有统计学差异。结论改良内侧撑开楔形胫骨高位截骨矫正老年膝内翻,是一种适合60岁以上患者的有效方法之一。不仅手术方法简便、组织损伤小、出血少、不易发生并发症,而且术后恢复快、住院时间短、不需要特殊昂贵的耗材,容易被广大患者接受,具有良好的社会效益和经济效益。     

Combined medial open-wedge high tibial osteotomy and modified Maquet procedure for medial compartmental osteoarthritis and patellofemoral arthritis of the knee

Purpose

Patellofemoral arthritis comes frequently with medial compartmental osteoarthritis. The combination of closed wedge high tibial osteotomy with tibial tuberosity anteriorization osteotomy has been introduced in several reports, but this technique is a technically demanding procedure and the outcomes of this technique show variable results. This article describes a novel osteotomy technique that combines medial open-wedge high tibial osteotomy (HTO) and tibial tuberosity anteriorization osteotomy (TTAO) for medial compartmental osteoarthritis and patellofemoral arthritis of the knee.

Methods

Twelve knees in 10 patients who were diagnosed with combined medial compartmental osteoarthritis with patellofemoral compartmental arthritis were treated with the combination of medial open-wedge HTO and TTAO and were followed up for more than 1 year. We evaluated the patients with the Lysholm functional questionnaires, the hospital for special surgery score (HSS), and the international knee documentation committee (IKDC) criteria (mean follow-up, 14.8 months).

Results

Union was achieved in all cases within 12 weeks. The mean Lysholm score increased from 42 preoperatively to 82.5 postoperatively (p < 0.001), the HSS increased from 57.5 preoperatively to 83 postoperatively (p < 0.001), and the IKDC score increased from 51 preoperatively to 82 postoperatively (p < 0.001). There were no other complications, such as iatrogenic fractures, nonunion, wound problem, collapse or loss of correction, and so on.

Conclusions

The combination of medial open-wedge HTO and modified Maquet procedure (TTAO) is considered to be an effective treatment modality for medial and patellofemoral compartmental osteoarthritis. This technique could, therefore, constantly provide a minimally invasive, precise correction of the deformity and a firm fixation that is enough to allow early rehabilitation.     

Open-wedge osteotomy of the proximal tibia hemicallotasis.

Conventional high tibial osteotomy for losteoarthritis of the medial compartment of the knee with closed-wedge or dome osteotomy (DMO) may produce shortening of the patellar tendon and loss of inclination of the proximal tibial plateau or of the offset of the tibial condyle relative to its bony axis. This can make subsequent total knee arthroplasty technically demanding. We undertook a prospective study comparing these changes after DMO with those after using open-wedge osteotomy hemicallotasis (HCO). A total of 50 knees with arthritis of the medial compartment in 46 consecutive patients was randomly allocated to either DMO or HCO. There were no significant differences between the groups with regard to age, gender, femorotibial angle before operation or the angle of correction. Radiological studies showed that HCO caused little change in the length of the patellar tendon or the inclination angle of the tibial plateau, while after DMO both gradually decreased. The degree of tibial condylar offset increased in both groups, but less so in the HCO group.     

内侧撑开和外侧闭合胫骨高位截骨术治疗膝内翻骨关节炎

目的 比较两种胫骨高位截骨术的手术方法和临床结果.方法 膝内翻骨关节炎患者68例,其中37例采用外侧闭合胫骨高位截骨术(closed wedge high tibial osteotomy,CWO),31例采用内侧撑开胫骨高位截骨术(open wedge high tibial osteotomy,OWO).术后摄X线片测量胫骨平台后倾角、髌骨高度、胫骨股骨角、内侧胫股关节间隙宽度,并行HSS和Lysholm功能评分.结果 患者均随访24个月以上.术前、术后两组HSS和Lysholm评分差异均无统计学意义.(1)CWO组术前胫骨平台后倾角8.57°±1.63°、术后5.03°±1.24°,OWO组术前8.71°±1.66°、术后10.10°±1.30°,差异均有统计学意义.(2)CWO组术前Insall-Salvati指数0.880±0.053、术后0.820±0.049,差异有统计学意义;OWO组术前0.892±0.043、术后0.897±0.042,差异无统计学意义.CWO组术前Blackburne-Peel指数0.804±0.040、术后0.801±0.339,差异无统计学意义;OWO组术前0.815±0.039、术后0.766±0.037,差异有统计学意义.(3)术后CWO组外翻8.06°±2.75°,OWO组外翻8.65°±1.46°.结论 膝内翻骨关节炎的内侧撑开和外侧闭合胫骨高位截骨术有相似的手术效果,内侧撑开截骨术截骨角度更加准确.外侧闭合胫骨高位截骨术后可出现胫骨后倾减小和髌韧带短缩,内侧撑开截骨术后易出现胫骨后倾增加和髌骨至关节线距离减小.     

Medical and lateral gonarthrosis treated with high tibial osteotomy. A prospective study

A prospective series comprising 52 knees in 48 patients suffering from medial or lateral unicompartmental gonarthrosis and treated by means of high tibial osteotomy shows, by comparing mechanical axis (MA) 0 degrees corrected knees, how important is the overcorrection of the MA into valgus in medial osteoarthritis. The clinical results were significantly correlated to overcorrection, the results 2 years postoperatively being better than those obtained at a follow-up 1 year after the operation. Of the results, 82% were good within a limit of +/- 3 degrees after 2 years, while only 77% were correspondingly good 1 year postoperatively. In lateral gonarthrosis overcorrection was not as good, but there was a mean overcorrection of +2 degrees, and with respect to this overcorrection, the results were quite acceptable. The results were directly correlated to the opening up of the joint space affected (80%) and diminution or disappearance of subluxation, 1/3 being 0 degrees preoperatively, 1/2 postoperatively in medial gonarthrosis. In lateral gonarthrosis, subluxation was increased, with 2/3 being 0 degrees preoperatively, 1/3 being 0 degrees postoperatively. The extension deficit in varus knees significantly diminished after valgus osteotomy; the change in valgus knees was also evident but not significant. The mean value of extension deficit was below 5 degrees in all cases at the 2 years' follow-up examination. However, 95% of all patients showed good or fair results after a follow-up period of 2 years.     

High tibial osteotomy. A prospective clinical and roentgenographic review

In a prospective clinical and roentgenographic analysis of 79 knees treated by a valgus closing wedge high tibial osteotomy, the average follow-up period was 5.8 years (three to nine years); 80% of the patients had good or excellent results. Correction to a femorotibial angle between 6 degrees and 14 degrees of femorotibial valgus was associated with an optimal clinical result. Undercorrection to less than 5 degrees of femorotibial valgus was associated with a high (62.5%) failure rate. Patients whose distal femur had a femoral shaft-transcondylar (FS-TC) angle of less than 9 degrees have an increased incidence of undercorrection. A poor prognosis was noted in knees whose patellofemoral joint preoperatively had moderate or severe roentgenographic evidence of osteoarthritis (OA) when compared to the group whose patellofemoral compartment had no or mild roentgenographic evidence of OA. Accurate femorotibial realignment was essential for success. The slope of the distal femoral articular surface, the FS-TC angle, affects the degree of correction and should be considered in preoperative planning.     

L’altezza della rotula dopo osteotomia tibiale prossimale: confronto fra tecnica di addizione mediale e sottrazione laterale

The clinical and radiographic results of patients with unicompartmental osteoarthritis or axial malalignment of the knee surgically treated with two different techniques of osteotomy of the proximal tibia were analysed. The patients, matched for age, sex and deformities, were divided into two groups: 47 cases treated with closed-wedge high tibial osteotomy and 40 cases with open-wedge high tibial osteotomy. For each case the height of the patella was measured by the Caton Method before surgery and at the last follow-up (at least 1 year after surgery). The purpose of this study was to analyse and search for any possible correlation between the variation of the patella and the degree of correction of the mechanical axis. It was concluded that patellar height after final osteotomy of the proximal tibia is modified and depends on the surgical technique used. Our study has shown a more frequent loss of patellar height with open-wedge high tibial osteotomy rather than closed-wedge high tibial osteotomy, the latter followed by a rather high rate of patellar elevation.     

Medial and lateral gonarthrosis treated with high tibial osteotomy

Summary A prospective series comprising 52 knees in 48 patients suffering from medial or lateral unicompartmental gonarthrosis and treated by means of high tibial osteotomy shows, by comparing mechanical axis (MA) 0° corrected knees, how important is the overcorrection of the MA into valgus in medial osteoarthritis. The clinical results were significantly correlated to overcorrection, the results 2 years post-operatively being better than those obtained at a follow-up 1 year after the operation. Of the results, 82% were good within a limit of ± 3° after 2 years, while only 77% were correspondingly good 1 year postoperatively. In lateral gonarthrosis overcorrection was not as good, but there was a mean overcorrection of + 2°, and with respect to this overcorrection, the results were quite acceptable. The results were directly correlated to the opening up of the joint space affected (80%) and diminution or disappearance of subluxation, 1/3 being 0° preoperatively, 1/2 postoperatively in medial gonarthrosis. In lateral gonarthrosis, subluxation was increased, with 2/3 being 0° preoperatively, 1/3 being 0° postoperatively. The extension deficit in varus knees significantly diminished after valgus osteotomy; the change in valgus knees was also evident but not significant. The mean value of extension deficit was below 5° in all cases at the 2 years¹ follow-up examination. However, 95% of all patients showed good or fair results after a follow-up period of 2 years.     

Changes in osseous correction after proximal tibial osteotomy: radiostereometry of closed- and open-wedge osteotomy in 33 patients

33 patients (22 men), median age 54 (40-68) years, with medial gonarthrosis grades 1-3, were treated by closed-wedge osteotomy (high tibial osteotomy = HTO, n 16) or open-wedge osteotomy by hemicallotasis (hemicallotasis osteotomy = HCO, n 19). 2 patients were operated on bilaterally. The patients were studied by RSA (radiostereometric analysis) for measuring 3-D changes in the correction achieved. In the HTO group the RSA measurements were obtained at the time of plaster removal, 1 month later and 1 year after surgery. In the HCO group, the RSA measurements were performed at the time of removal of the external fixator, 1 month later and 1 year after surgery. After removal of the fixation, HTO was associated with increased medial/lateral and distal translation of the proximal segment, compared to HCO. In addition, the tibial plateau rotated more around the longitudinal axis of the tibia after HTO.     

Changes in osseous correction after proximal tibial osteotomy: Radiostereometry of closed- and open-wedge osteotomy in 33 patients

33 patients (22 men), median age 54 (40-68) years, with medial gonarthrosis grades 1-3, were treated by closed-wedge osteotomy (high tibial osteotomy = HTO, n 16) or open-wedge osteotomy by hemicallota-sis (hemicallotasis osteotomy = HCO, n 19).

2 patients were operated on bilaterally. The patients were studied by RSA (radiostereometric analysis) for measuring 3-D changes in the correction achieved. In the HTO group the RSA measurements were obtained at the time of plaster removal, 1 month later and 1 year after surgery. In the HCO group, the RSA measurements were performed at the time of removal of the external fixator, 1 month later and 1 year after surgery.

After removal of the fixation, HTO was associated with increased medial/lateral and distal translation of the proximal segment, compared to HCO. In addition, the tibial plateau rotated more around the longitudinal axis of the tibia after HTO.     

Intermediate follow-up on the double osteotomy and tendon transfer procedure for stage II posterior tibial tendon insufficiency

26 patients with 28 pes planovalgus feet secondary to Johnson stage 2 posterior tibial tendon insufficiency were treated with flexor digitorum longus tendon transfer, lateral column lengthening, medial displacement calcaneal osteotomy, and heel cord lengthening. The mean patient age at surgery was 48.5 years. The AOFAS ankle-hindfoot scale was applied postoperatively to assess clinical outcome. Preoperative and postoperative standing radiographs of the foot and ankle were analyzed to determine radiographic correction of the pes planovalgus deformities. The mean follow-up to date is 5 years. The mean ankle-hindfoot score was 90 postoperatively. The medial cuneiform to fifth metatarsal distance improved from -0.2 mm preoperatively to 7.6 mm postoperatively. Similarly, the talonavicular distance improved from 19.4 mm preoperatively to 10.9 postoperatively. There were no nonunions. Four feet (14%) displayed radiographic signs of calcaneocuboid arthritis at follow-up. Only one was symptomatic requiring calcaneocuboid joint fusion. The double osteotomy technique provides symptomatic relief and lasting correction of the pes planovalgus deformity associated with stage 2 posterior tibial tendon insufficiency at intermediate follow-up. It has a high patient satisfaction based on the AOFAS ankle-hindfoot scale and radiographic measurements demonstrate maintenance of correction of the adult acquired flatfoot.     

合并膝内翻骨性关节炎全膝关节置换的处理

目的探讨膝骨性关节炎合并膝内翻畸形者行膝关节置换时膝内翻的矫正方法。方法172例（190膝）合并内翻畸形骨性关节炎患者进行全膝关节表面置换术。术前测量膝内翻角、关节面夹角、胫骨角、胫骨内翻角及胫骨平台后倾角,其内翻角为8°～21°,参考关节面夹角、胫骨角及胫骨内翻角确定膝内翻的类型,术中根据膝内翻的类型及构成因素进行相应的胫骨截骨及适度的软组织松解。结果出现切口感染2例（2膝）,1例为急性感染,1例为迟发性感染,2例均经清创、假体取出并膝关节融合术后痊愈。术后内翻矫正157膝,仍有膝内翻33膝,内翻角3°～9°（4.8°±0.9°）。165例（182膝）获得随访,时间8～90（40±3.5）个月。末次随访时除2例感染外,余膝关节活动度为：伸直0°168膝,伸直受限＆lt;10°11膝,伸直受限11°～15°3膝;屈曲90°～130°。临床及X线检查未见明显松动迹象。HSS膝关节评分由术前12～57（30±5.5）分提高到76～89（79.2±4.3）分。结论术前明确膝内翻的类型及构成因素,术中采取针对性操作进行适度的软组织松解及正确的截骨,是全膝关节置换膝内翻获得矫正的有效方法。     

开放胫骨高位楔形截骨术治疗膝关节内翻畸形

目的 评价双平面开放胫骨高位楔形截骨治疗成人膝关节内翻畸形的手术效果.方法 回顾性分析2001年6月至2008年7月存在膝关节内侧单间室退行性改变伴内翻畸形且进行双平面开放胫骨高位楔形截骨术治疗的12例患者的一般资料.术前膝内翻畸形5.0°～19.0°,平均11.5°;膝关节屈伸活动度大于90°;不伴有其他关节间室病变;1例伴有外侧副韧带及前交叉韧带断裂,行韧带重建手术后二期进行开放截骨矫形术.术前膝关节症状以内侧间室疼痛为主.手术前后测量患者关节活动度的大小,并对患者进行Lysholm评分.术后对患者进行主观满意度调查.结果 12例患者术后平均随访时间32.5个月.截骨处至术后12～16周均获得骨性愈合.矫正角度5.5°～18.0°,平均9.5°.在随访期间内X线检查下肢力线维持在术后水平,内外侧间室及髌股间室均未发现明显退变进展.手术总体效果优良率为83.3%,Lysholm评分、内翻角度变化在手术前后均有统计学显著性差异.结论 双平面开放胫骨高位楔形截骨术对中青年膝关节内翻畸形伴单间室退行性改变有良好的早、中期效果.     

开放楔形胫骨高位截骨术不同程度矫正内翻畸形的比较

目的研究开放楔形胫骨高位截骨术(OWHTO)后过度矫正内翻畸形的并发症发生情况和临床疗效，并通过放射学指标比较髋关节、髌股关节与踝关节的代偿性变化。 方法回顾性分析2016年1月至2020年5月期间在青岛大学附属医院行OWHTO治疗的63例患者的资料，纳入标准为诊断明确、有症状的膝骨关节炎伴内翻畸形，排除双侧手术、术前有膝关节感染及既往外伤史的患者。根据术后测量承重线比率(WBLR)，将所有患者分为正常矫正组52例(50%2＝4.395，P＝0.036)。在OWHTO后，比较两组患者末次HKA和MPTA，差异有统计学意义(t＝6.586、3.709，均为P<0.001)，比较末次随访两组患者HAA，差异有统计学意义(t＝-2.309，P＝0.026)。其余影像学指标比较，差异均无统计学意义(均为P>0.05)。两组患者HSS评分、WOMAC评分末次随访比较，两组患者差异无统计学意义。 结论过度矫正内翻畸形(术后WBLR≥67%)不影响OWHTO后早期的临床效果，但增加了术后并发症的发生率，从影像学上，引起髋关节代偿性的内收加剧。     

The new “dual osteotomy”: combined open wedge and tibial tuberosity anteriorisation osteotomies

The high frequency with which medial compartment osteoarthritis is associated with patellofemoral osteoarthritis makes the addition of tibial tuberosity anteriorisation to high tibial osteotomy an appealing solution, despite the discouraging previously reported long-term results when tubercle anteriorisation was combined with a Coventry closed wedge technique. We conducted a prospective study of a new osteotomy combination: “the dual osteotomy”. An open wedge high tibial osteotomy was combined with 1- to 1.5-cm Maquet-like tibial tuberosity anteriorisation. Thirty-four knees in 30 patients underwent surgery, including ten knees in nine male patients and 24 knees in 21 female patients with a mean age of 45 years (age range 34−58 years). All patients had varus medial compartment osteoarthritis and patellofemoral osteoarthritis with preoperative anatomical tibiofemoral angle exceeding 5°. Twenty-four months after surgery, final evaluation detected improvement in the Knee Society clinical rating system function score from a mean of 61.3 (range 30−80) preoperatively to a mean of 87.3 (range 50−100) postoperatively and in the knee pain score from 27.3 (range 10−30) to 47 (range 30−50) postoperatively. Based on the rating system, at final follow-up, 70% of patients experienced no pain, 13% had mild or occasional pain, 10% had pain on stairs only, and 7% had pain during walking and on stairs. Anatomical tibiofemoral angles from 0 to 10° valgus were achieved in 91% of operated knees, and union was achieved in all cases within six to twelve weeks after surgery. The dual osteotomy was effective in the short term in cases of medial compartment osteoarthritis associated with patellofemoral osteoarthritis.     

外侧闭合楔形胫骨近端截骨术的远期疗效分析

[目的]探讨胫骨近端截骨术治疗原发性胫骨近端骨性关节炎的远期疗效以及最佳的截骨矫正角度.[方法]自1985～1997年,79例(111膝)原发性骨性关节炎患者接受了胫骨近端截骨术.其中男5例(5膝),女74例(106膝);年龄37～70岁(平均55岁).根据术后胫股角(FTA)分为3组.Ⅰ组61膝FTA<7°;Ⅱ组23膝FTA7°～9°;Ⅲ组27膝FTA≥10°.所有病例术前、术后按特种外科医院评分系统(HSS)评分.[结果]术后随访2年4个月～14年1个月(平均9年6个月).术前HSS平均60分,术后1年平均94分,末次随访平均87分.采用2种方法判定手术失败:方法1为需行人工全膝火节置换术者,随访4年和14年手术成功率分别为99%和85%;方法2为需行人工全膝关节置换术者或术后HSS评分<60分,随访4年和14年手术成功率分别为96.4%和75.1%.[结论]胫骨近端截骨术是治疗单间室骨性关节炎的有效方法,但术后胫股角应矫正到外翻7°以上(范围10°～15°).     

The effect of closed- and open-wedge high tibial osteotomy on tibial slope: a retrospective radiological review of 120 cases

Radiographs of 110 patients who had undergone 120 high tibial osteotomies (60 closed-wedge, 60 open-wedge) were assessed for posterior tibial slope before and after operation, and before removal of the hardware. In the closed-wedge group the mean slope was 5.7 degrees (SD 3.8) before and 2.4 degrees (SD 3.9) immediately after operation, and 2.4 degrees (SD 3.4) before removal of the hardware. In the open-wedge group, these values were 5.0 degrees (SD 3.7), 7.7 degrees (SD 4.3) and 8.1 degrees (SD 3.9) respectively, when stabilised with a non-locking plate, and 7.7 degrees (SD 3.5), 9.4 degrees (SD 4.1) and 9.1 degrees (SD 3.8), when stabilised with a locking plate. The reduction in slope (-2.7 degrees (SD 4.1)) in the closed-wedge group and the increase (+2.5 degrees (SD 3.4), in the open-wedge group was significantly different before and after operation (p = 0.002, p = 0.003). In no group were the changes in slope directly after operation and before removal of the hardware significant (p > 0.05). There was no correlation between the amount of correction in the frontal plane and the post-operative change in slope. Posterior tibial slope decreases after closed-wedge high tibial osteotomy and increases after an open-wedge procedure because of the geometry of the proximal tibia. The changes in the slope are stable over time, emphasising the influence of the operative procedure rather than of the implant.     

Open-wedge retro-tubercular tibial osteotomy: an innovating technique

Open-wedge tibial osteotomy for varus correction is a common orthopedic procedure. The rate of complications remains significant: loss of correction, nonunion, patellar infera... We propose a new open-wedge technique for tibial osteotomy which has several advantages: less risk of patella infera, improved bone healing, excellent mechanical stability. The osteotomy involves two cuts with an anterior portion ending distally to the tibial tubercle. This preserves the integrity of the patellar tendon and maintains contact between the proximal tibia and the tibial tubercle. Adjunction of an anteroposterior screw adds stability. The anterior plane of the osteotomy provides an excellent surface contact favoring bone healing. The posterior plane is the same as with a "classical" open-wedge osteotomy. The lateral cortical must always remain intact (hinge). The technique described here does not require any specific instrumentation and is compatible with most of the available osteosynthesis implants.     

High tibial osteotomy using polycaprolactone-tricalcium phosphate polymer wedge in a micro pig model

Medial open-wedge high tibial osteotomy has been gaining popularity in recent years, but adequate supporting material is required in the osteotomy gap for early weight-bearing and rapid union. The purpose of this study was to investigate whether the implantation of a polycaprolactone-tricalcium phosphate composite scaffold wedge would enhance healing of the osteotomy in a micro pig model. We carried out open-wedge high tibial osteotomies in 12 micro pigs aged from 12 to 16 months. A scaffold wedge was inserted into six of the osteotomies while the other six were left open. Bone healing was evaluated after three and six months using plain radiographs, CT scans, measurement of the bone mineral density and histological examination. Complete bone union was obtained at six months in both groups. There was no collapse at the osteotomy site, loss of correction or failure of fixation in either group. Staining with haematoxylin and eosin demonstrated that there was infiltration of new bone tissue into the macropores and along the periphery of the implanted scaffold in the scaffold group. The CT scans and measurement of the bone mineral density showed that at six months specimens in the scaffold group had a higher bone mineral density than in the control group, although the implantation of the polycaprolactone-tricalcium phosphate composite scaffold wedge did not enhance healing of the osteotomy.