Modified retro-tubercle opening-wedge versus conventional high tibial osteotomy

Despite the fact that common surgical techniques for the treatment of genu varum usually correct the malalignment in the affected knee, these methods have significant complications and cause problems in the long term. Retro-tubercle opening-wedge high tibial osteotomy is among the newer techniques for the treatment of genu varum. The goal of this study was to compare the results of retro-tubercle opening-wedge high tibial osteotomy with those of medial opening-wedge osteotomy. In a randomized, controlled trial, 72 patients with varus knees who were scheduled for surgery were assigned into either the retro-tubercle opening-wedge high tibial osteotomy (n=34) or medial opening-wedge osteotomy groups (n=38). Groups were matched for age and sex. The position of the patella was compared with respect to the tuberosity and the upper tibial slope pre- and postoperatively. Patients were followed for an average of 13 months (range, 10-21 months). In the retro-tubercle opening-wedge high tibial osteotomy group, the length of the patellar tendon did not significantly differ pre- and postoperatively (P≥.5); however, in the medial opening-wedge osteotomy group, a statistically significant shortening was noted in patellar tendon postoperatively (P≤.05). Similarly, the tibial plateau inclination showed a statistically significant difference postoperatively in the medial opening-wedge osteotomy group, while the difference in the retro-tubercle opening-wedge high tibial osteotomy group did not reach statistical significance.     

Mid-term outcome of opening-wedge high tibial osteotomy for varus arthritic knees

Gonarthrosis in the relatively young and active population causes major daily discomfort and disability. If the arthritic process is mainly limited to the medial compartment, the axis of a varus knee can be realigned laterally with high tibial osteotomy to unload the medial compartment and allow some cartilage regeneration and pain relief. This study describes the outcomes of patients who underwent opening-wedge high tibial osteotomies using Puddu plate (Arthrex, Naples, Florida) fixation. Eighteen patients (22 knees) with genu varum and medial compartment osteoarthritis were followed-up for an average of 6.3±2.3 years after high tibial osteotomy with Puddu plate fixation and iliac crest allograft. Clinical outcome was assessed by the Oxford Knee Score and subjective satisfaction rating. Pre- and postoperative radiographs were evaluated for tibiofemoral angle, Insall-Salvati index, and Kellgren-Lawrence Grading Scale for osteoarthritis. Mean patient age at surgery was 44±13.7 years, and mean body mass index was 29.1±4.7 kg/m(2). At last follow-up, mean Oxford Knee Score improved from 22.4±13.5 to 37.2±13.7 (P=.002). Average subjective satisfaction rate at last follow-up was 8±3. The measured tibiofemoral angle was corrected to an average genu valgum of 3.3°±4.8° (P=.001). No patient showed severe postoperative osteoarthritis (ie, Kellgren-Lawrence grade 4) at last follow-up. All radiographs showed full incorporation of the bone grafts. At the end of the study, 2 patients underwent total knee replacement. Opening-wedge high tibial valgus osteotomy with Puddu plate fixation can be a reliable procedure for the treatment of medial-compartment osteoarthritis of the knee associated with varus deformity.     

内侧张开胫骨高位截骨术中未植骨的预后研究

目的研究内侧张开胫骨高位截骨术中不植骨的术后骨预合情况。方法回顾性分析2008年1月至2012年1月内侧张开胫骨高位截骨术43例,分为A、B两组,A组术中植骨(骨移植或采用羟基磷灰石人工骨),B组未植骨,比较两组骨性愈合程度、愈合时间、完全负重时间及并发症情况等。结果两组各项临床指标无统计学差异,其中A组骨愈合时间(16.42±1.53)周,B组骨愈合时间(17.80±1.72)周(P=0.08)。随访期间未出现内固定失效、钢板松动断裂、感染等并发症。结论内侧张开胫骨高位截骨术中不植骨也可获得满意预后。     

Biomechanical evaluation of a high tibial osteotomy with a meniscal transplant

This study determines the biomechanical advantage and the optimal configuration of a high tibial osteotomy (HTO) and meniscus transplantation performed concurrently. Six cadaver knees were placed in a spatial frame, and an HTO was completed. Loading points between a mechanical 6 degrees of varus and 8 degrees ofvalgus were loaded to 800 N for medial meniscal intact, meniscectomized, and transplanted states. Posterior slope was also increased by 3 degrees in these specimens. Contact data was recorded. Peak pressures significantly increased in the meniscectomized state in every degree of varus/valgus (p < 0.05). For both peak and total medial compartment pressures, there was a significant drop (p < 0.001) between neutral and 3 degrees of valgus. Lateral compartment pressures linearly increased from varus to valgus orientation. There was no significant change in the pressure profile of the knee with a 3-degree increase in posterior slope. This biomechanical study confirms the hypothesis that an HTO improves the peak pressures in the medial compartment at all degrees of varus/valgus alignment in the setting of meniscal transplantation. Furthermore, the largest decrease in medial pressures was between neutral and 3 degrees of valgus, suggesting that perhaps neutral aligned knees could benefit from an HTO.     

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.     

Changes in load distribution in the knee after opening-wedge or closing-wedge high tibial osteotomy

The treatment of unicompartmental osteoarthritis of the knee by high tibial osteotomy has been carried out by closing-wedge osteotomy. The advantages for opening-wedge osteotomy are ease of procedure and improved correction with comparable short-term to midterm results. It is not known how the opening-wedge high tibial osteotomy procedure alters the load distribution between the medial and lateral compartments of the knee. The current biomechanical study investigated opening-wedge vs closing-wedge osteotomies in 5 pairs of cadaver knees. The results showed that at 5 degrees osteotomy, the closing-wedge provided superior results of load transfer from medial to lateral compartment than that seen with opening-wedge, but at 10 degrees osteotomy, there was no significant difference in load transfer in the knee compartments between the 2 surgery modes.     

Fixation stability following high tibial osteotomy: a radiostereometric analysis

Fifteen patients with varus gonarthrosis underwent high tibial osteotomy and internal fixation with an L-shaped rigid plate. In 9 patients, an average wedge size of 7.1 degrees was resected leaving the medial cortex of the proximal tibia intact (group 1). In 6 patients, the medial cortex of the proximal tibia was unintentionally fractured during surgery when an average 10.7 degrees wedge was resected (group 2). Postoperatively, patients were monitored with serial radiostereometric analysis (RSA), conventional radiographs, and clinical evaluation for 1 year. In group 2, RSA revealed a 1.3-mm increase in lateral displacement of the distal tibial segment within 3 weeks following surgery. Twelve weeks after surgery, micromotion between tibial segments was below the precision of the RSA setup in 14 of 15 patients. These findings indicate that in cases with larger wedge sizes (>8 degrees), fracture of the medial cortex of the proximal tibia was frequent and resulted in significant lateral displacement of the distal tibia relative to the tibial plateau. In such cases, prophylactic additional medial fixation rather than lateral L-plate fixation alone is advised to minimize the propensity for lateral displacement of the distal tibia and to avoid subsequent loss of correction.     

Low-intensity pulsed ultrasound accelerates maturation of callus in patients treated with opening-wedge high tibial osteotomy by hemicallotasis

BACKGROUND: Opening-wedge high tibial osteotomy by hemicallotasis for osteoarthritis in the medial compartment of the knee requires external fixation for a long time, until callus maturation is complete. The aim of this study was to determine if low-intensity pulsed ultrasound would accelerate callus maturation when applied after distraction to limbs treated with opening-wedge high tibial osteotomy by hemicallotasis. METHODS: Twenty-one patients with symmetric grades of osteoarthritis and similar degrees of varus deformity in the two knees underwent bilateral one-stage opening-wedge high tibial osteotomy by hemicallotasis. After completion of distraction, the bone mineral density of the distraction callus was measured. Then, one randomly selected limb was subjected to ultrasound treatment for twenty minutes daily until removal of the external fixator. The contralateral limb was left untreated to serve as the control. After four weeks of treatment, bone mineral density was measured again. RESULTS: During the four-week treatment period, the mean increase in callus bone mineral density was significantly greater in the ultrasound-treated tibiae (0.20 +/- 0.12 g/cm(2)) than in the control tibiae (0.13 +/- 0.10 g/cm(2)) (p = 0.02, unpaired t test). In eighteen patients the increase in the bone mineral density was greater in the ultrasound-treated limb than in the control limb, whereas in three patients the increase was greater in the control limb. CONCLUSIONS: We found that low-intensity pulsed ultrasound applied during the consolidation phase of distraction osteogenesis accelerates callus maturation after opening-wedge high tibial osteotomy by hemicallotasis in elderly patients.     

Incidence and risk factors for surgical site infection after medial opening-wedge high tibial osteotomy using a locking T-shape plate

Medial opening-wedge high tibial osteotomy (MOWHTO) is a well-established surgical method for treatment of isolated medial compartment osteoarthritis with varus deformity, but the surgical outcomes may be compromised by surgical site infection (SSI). This study aimed to investigate the incidence and the risk factors for SSI after MOWHTO. This retrospective study included consecutive patients who underwent MOWHTO for isolated medial compartment osteoarthritis with varus deformity in two tertiary referral hospitals from January 2019 and June 2021. Patients who developed SSI within 12 months of surgery were identified by inquiring the medical records for index hospitalisation, notes of after-discharge outpatient visits, or records of readmission for treatment of SSI. Univariate comparisons were performed to detect the differences between SSI and non-SSI groups, and multivariate logistic regression analysis was used to identify the independent risk factors. Six hundred sixteen patients with 708 procedures were included and 30 (4.2%) cases of SSI occurred, with 0.6% rate for deep SSI and 3.6% for superficial. Univariate analyses showed significant difference between groups in terms of morbidity obesity (≥32 kg/m²) (20.0% vs 8.9%), comorbid diabetes (26.7% vs 11.1%), active smoking (20.0% vs 6.3%), time from admission to operation (5.2 ± 4.0 vs 4.1 ± 3.0), size of osteotomy ≥12 mm (40.0% vs 20.0%), type of bone grafting and lymphocyte count (2.1 ± 0.5 vs 1.9 ± 0.6). However, in the multivariate analysis, only active smoking (OR, 3.4; 95% CI, 1.4-10.2), size of osteotomy ≥12 mm (OR, 2.8; 95% CI, 1.3-5.9) and allogeneic/artificial vs no bone grafting (OR, 2.4; 95% CI, 1.0-10.8) remained significant. SSI was not uncommon after MOWHTO, but the majority was superficial. The identified three independent factors, including smoking, size of osteotomy ≥12 mm and allogeneic/artificial bone grafting would help risk assessment and stratification, target risk factor modification and clinical surveillance, and inform patient counselling.     

Biomechanical comparison of two different locking plates for open wedge high tibial osteotomy

Background

The purpose of this study was to compare the mechanical stability of a relatively thin locking plate (FlexitSystem implant) with a relatively firm locking plate (TomoFix implant), both used for opening wedge high tibial osteotomy.

Medial opening-wedge high tibial valgus osteotomy, using a stable TomoFix plate, in genu varum arthritis: surgical technique

The authors present the technique of high tibial correction osteotomy by the medial opening procedure, with the use of an angle-stable TomoFix plate. The prerequisite for a long-term good outcome of corrective osteotomy in genu varum is to achieve limb alignment permitting transfer of weight-bearing from the affected medial compartment to the healthy lateral compartment of the knee. The development of implants that maintain a stable angle has facilitated corrective osteotomy with an opening wedge on the medial side of the proximal tibia. These implants provide stable fixation even when a high correction of the mechanical axis is needed. The authors present the case of a patient with varus malalignment following a fracture of the tibia. In order to achieve correction of the limb's mechanical axis, it was necessary to open the proximal tibia osteotomy with a wedge that was 2.5 cm on the outer side.     

Biomechanical superiority of plate fixation for proximal tibial osteotomy

Proximal tibial osteotomies require secure and durable fixation to allow early range of motion; however, biomechanical data comparing commonly used fixation methods are lacking. The current study was done to quantify the dynamic biomechanical performance of blade staple fixation and plate fixation of simulated proximal tibial osteotomies. A 15 degrees proximal tibial osteotomy was done on each of 18 synthetic adult composite tibias. Blade staples were used as the means of fixation in nine tibias; plate fixation was used in the remaining nine tibias. The specimens were stressed cyclically in sinusoidal loading whose peak compression and tension loads imitate those measured during normal gait. Device performance was quantified by measuring displacement at the osteotomy site and the number of cycles to failure. Plate fixation had a greater fatigue life than staples (eight plates surviving past 200,000 cycles versus one blade staple) and showed a trend toward less displacement (0.69 mm versus 0.97 mm). Plate fixation of proximal tibial osteotomies offers better fixation and dynamic mechanical performance than blade staples.     

Primary stability of different implants used in conjunction with high tibial osteotomy

High tibial osteotomy in the varus knee has been successfully performed for a long time. Several newer operation techniques have been established in recent years. We tested the primary stability of several of these techniques in vitro. Ten human cadaveric fresh-frozen specimens were used that had a mean age of 54 years (range 29-72 years) and a weight of 55-85 kg. All specimens were harvested, frozen, and subsequently thawed under the same conditions before testing. The following implants were tested: one-third tubular plate with a cortical screw (AO, Synthes), blade plate with screws (Giebel's plate, Link), bone staples (osteotomy staples, Krackow staples, Smith & Nephew) and an external fixator (Orthofix). The specimens were mounted in metal cylinders and then loaded in two different setups: transverse forces were applied to the osteotomy site by hanging weights parallel to the osteotomy plane in a static-loading frame, and axial forces were applied by a materials testing machine (Zwick). Displacement was recorded using a linear variable displacement transducer (LVDT). The highest stability was achieved by the external fixator and the bone staples. Giebel's blade plate and the one-third tubular plate were less stable. Retention of an intact medial cortex was a decisive factor in obtaining primary stability. We found that the primary stability of the tested devices was generally comparable as long as they were correctly implanted. It was also noted that lateral spacing of the osteotomized bone should not exceed 3 mm. If the medial cortex is transected intraoperatively in lateral osteosynthesis, an additional medial implant is necessary to ensure sufficient primary stability. For practical reasons it was necessary to neglect the contribution of the soft tissues around the knee, although all implants were tested under the same conditions. Care should thus be taken when interpreting the results of this study in a clinical setting.