全膝关节置换治疗膝关节外翻畸形大于90度(2019)

全膝关节置换治疗膝关节外翻畸形大于90度(2019) Total knee arthroplasty for a valgus deformity angle of ＞90 degrees : A case report

Guo J, Cao G, Zhang Y, Song W, Qin S, Ma T, Wang Y, Yang W. Total knee arthroplasty for a valgus deformity angle of ＞90 degrees : A case report[J]. Medicine (Baltimore), 2019,98(23): e15745.

转载文章的原链接1：

https://pubmed.ncbi.nlm.nih.gov/31169673/

转载文章的原链接2：

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6571272/

Abstract

Rationale:

Valgus knees are relatively rare in the clinic. Treatments for valgus deviations ＞90° represent a surgical challenge to achieve a balance between the soft tissue and bone and prevent nerve damage.

膝外翻在临床上比较少见。外翻偏差＞90°的治疗是实现软组织和骨骼之间平衡并防止神经损伤的外科挑战。

Patient concerns:

A 63-year-old woman with valgus deviations ＞90° in both knees complained that she had been unable to walk for 50 years.

一名63岁女性，双膝外翻＞90°，自诉已不能行走50年。

Diagnoses:

Congenital malformation valgus deformity.

先天性外翻畸形

Interventions:

Bilateral total knee arthroplasty (TKA) was performed using a rotating hinge knee instrument from Endo-Model for axial correction and stabilization of the joint.

双侧全膝关节置换术(TKA)采用Endo-Model的旋转铰链膝关节器械进行轴向矫正和关节稳定。

Outcomes:

The patient fully recovered 3 months after surgery. At the follow-up 6 years after the operation, the function of the knee joint clearly improved. The knee society score (KSS) increased from 35 to 90.

术后3个月患者完全康复。术后随访6年，膝关节功能明显改善。膝关节协会评分(KSS)由35分上升至90分。

Lessons:

Constrained implants are commonly used to stabilize the joint and correct the bone axis in patients with severe ligamental instability, gross deformity, bone loss, and extreme deviation of the straight leg axis. Intraoperative exploration of the common peroneal nerve and the postoperative flexed position of the knee joints could help prevent nerve injuries.

对于严重韧带不稳、严重畸形、骨质缺失和直腿轴极度偏离的患者，限制性假体通常用于稳定关节和矫正骨轴。术中探查腓总神经及术后膝关节屈曲位置有助于预防神经损伤。

Keywords: total knee arthroplasty, valgus deformity, hinge knee

1. Introduction

Total knee arthroplasty (TKA) is used to treat knee valgus deformity, and approximately 10% of all patients who require TKA present with valgus deformity.[1,2] According to the Keblish classification, the femorotibial angle (FTA) can be measured on the x-ray image of the valgus deformity; a mild angle is ＜15°, a moderate degree is 15° to 30°, and a severe deformity is an angle ＞30°.[3] Because of the different tensions of soft tissue and bone defects, different prostheses can be selected. For mild deformities and some moderate and severe knee valgus deformities, we can first release the lateral collateral ligament through tenolysis of the soft tissue then release the posterolateral articular capsule, the iliotibial band and the lateral head of the gastrocnemius, biceps tendon, and popliteal tendon tissue. Thus, soft-tissue balance can be obtained. For moderate and some severe valgus knee deformities, posterior cruciate-retaining total knee prostheses, constrained condylar knee prostheses, or varus-valgus constrained implants can be used to obtain a good result.[4] Some of the more severe valgus knee deformities with bone defects need to be fixed with an extension rod and the placement of a spacer block to achieve balance and stability. However, for some patients with severe deformities of the valgus knee, surface prostheses with soft tissue release are unable to achieve balance and stability. These cases often require the use of a hinge knee prosthesis to solve the problem. Hinge knee prostheses with good coronal stability can stably replace soft-tissue balance, but complications of looseness can occur, which are mainly due to sagittal alignment because the sagittal plane outputs a high amount of power; this pull eventually leads to prosthesis loosening.[5–7] Nonetheless, the loosening rate of the Endo-Model hinge prosthesis reported in the previously published literature is low.[8–11]

[3] Keblish PA. The lateral approach to the valgus knee. Surgical technique and analysis of 53 cases with over two-year follow-up evaluation. Clin Orthop Relat Res 1991;271:52–62.

全膝关节置换术(TKA)用于治疗膝关节外翻畸形，大约10%需要全膝关节置换术的患者存在外翻畸形[1,2]。根据Keblish分类，可以在外翻畸形的X线图像上测量股胫角(FTA);轻度畸形为＜15°，中度畸形为15°至30°，重度畸形为＞30°[3]。由于软组织张力和骨缺损的不同，可以选择不同的修复体。对于轻度畸形和部分中重度膝外翻畸形，可先通过软组织松解术松解外侧副韧带，然后松解后外侧关节囊、髂胫束和腓肠肌外侧头、二头肌肌腱、腘肌腱组织。因此，可以获得软组织平衡。对于中度及部分重度外翻膝关节畸形，可采用后交叉韧带保留假体的全膝关节假体、限制性髁膝关节假体或内外翻限制性假体，均可获得较好的效果[4]。一些更严重的外翻膝关节畸形伴骨缺损需要用延伸棒和放置间隔块来固定，以达到平衡和稳定。然而，对于一些外翻膝关节严重畸形的患者，具有软组织松解的表面假体无法达到平衡和稳定。这些病例通常需要使用铰链膝关节假体来解决问题。具有良好冠状面稳定性的铰链式膝关节假体可以稳定地替代软组织平衡，但由于矢状面输出功率大，因此可能出现松动并发症，这主要是由于矢状面对准所致;这种拉力最终会导致假体松动[5-7]。然而，先前发表的文献报道的endo model铰链假体的松动率很低[8-11]。

Knee valgus deformities can be congenital or may occur secondary to conditions such as osteoarthrosis, rheumatic diseases, and posttraumatic arthritis, or to an overcorrection following a valgus osteotomy.[4] Valgus deviations ＜20°, which account for approximately 95% of all valgus knees, are relatively easy to correct with surgery.[2] However, the correction of valgus deviations ＞20° is a challenging undertaking for joint surgeons.[2,12] Herein, we report a case of severe valgus deformity with a valgus deviation ＞90° in a 63-year-old woman who was successfully treated with TKA. To the best of our knowledge, this is the first documented case of successful treatment of a ＞90° valgus deformity with TKA. The patient and her family have consented to the publication of this article.

膝外翻畸形可能是先天性的，也可能是由骨关节病、风湿性疾病和创伤后关节炎等继发疾病引起的，或者是外翻截骨术后矫治过度引起的[4]。外翻偏差＜20°约占所有外翻膝关节的95%，相对容易通过手术矫正[2]。然而，对于关节外科医生来说，矫正＞20°的外翻是一项具有挑战性的工作[2,12]。在此，我们报告一例63岁女性外翻畸形，外翻偏度＞90°，经TKA成功治疗。据我们所知，这是第一例用TKA成功治疗＞90°外翻畸形的病例。患者及其家属已同意发表这篇文章。

2. Case report

A 63-year-old woman presented at our hospital with congenital malformation valgus deformity ＞90° (Fig. 1A, B). An x-ray of the knee showed a malformed femoral condyle and tibial plateau with severe bone defects (Fig. 2). According to the Keblish classification, this case was classified as a severe deformity.[3] The patient has not been able to walk normally since the age of 12. The muscle strength of the quadriceps was low. A physical examination showed that all ligaments around the knee were slack. Through the above examination, the patient‘s knee society score (KSS) score was assessed to be 35.[13] The knee extension reached 90°, and the flexion reached 80°.

Figure 1 (A, B) Preoperative photograph of the patient showing severe knee valgus deformity.

Figure 2 Preoperative x-ray radiograph (nonweight-bearing) showing malformations and bony defects in the femoral condyle and the tibial plateau.

Before the operation, we created a three dimensional model of both knees, simulated the patella trajectory and carefully examined the patient‘s soft tissue tightness. Due to the presence of severe bone defection and the severe relaxation of the medial and lateral soft tissue devices, the Endo-Model rotating hinge knee prosthesis was chosen for the patient, and a bilateral TKA was performed. The knee joints were exposed via a medial parapatellar approach to achieve a good view because we did need to worry about soft-tissue balance. The femoral condyles were severely deformed with a small lateral femoral condyle and a relatively large medial femoral condyle. Tibial extorsion, lateral dislocation of the patella, and severe degeneration of articular surfaces of the femur, tibia, and patella were also observed. Bone hyperplasia and syndesmophyte formation around the joint were observed along with the worn medial and lateral menisci. The anterior and posterior cruciate ligaments were almost invisible.

After resection of the hyperplastic osteophyte and synovial membrane, the iliotibial band was first released, then the lateral retinaculum was released. Subsequently, the lateral ligament was directly incised.

Because the ligaments around the knee were slack, the Endo-Model rotating hinge knee prosthesis was used. Based on the preoperative x-ray, the femoral canal in the medial femoral condyle was selected as the entry point for the intramedullary guide. After the internal rotation, external rotation, alignment, and tautness of the knee joint were tested to meet the physiological requirements, the Germany Link knee prosthesis (left knee: tibia size 55 mm/160 mm, femur size 55 mm/160 mm, poly size 16mm; the right knee prosthesis was the same size as the left) was installed. Full release of the patellar lateral retinaculum and strengthening of the patellar medial retinaculum were performed to correct the lateral patellar dislocation. After surgery, the knees were in good alignment. The ankle activity was normal. One day after surgery, the patient was unable to dorsiflex the ankle joints. The nervus peroneus communis was suspected to have been damaged by traction. The patient received an oral methylamine dispersible tablet and performed joint functional exercises. One week after surgery, the movements of the knee joint ranged from 5° to 90°. The x-ray image showed an appropriate prosthesis position (Fig. 3).

Figure 3 Postoperative x-ray radiograph showing the implanted prosthesis.

The only postoperative complication was an injury to the peroneal nerve, which led to loss of dorsiflexion at both ankle joints. However, the patient was able to walk with the use of walking aids. The patient was regularly followed up, and the ankle motion deficit was found to be completely recovered 3 months after surgery. At the follow-up 6 years after the operation, the knee extension reached 180°, knee flexion reached 125°, and the active joint function clearly improved (Fig. 4). The KSS had improved to 80 at the 2-year follow-up, 87 at the 4-year follow-up, and 90 at 6-year follow-up.

Figure 4 Postoperative photograph after 18 months showing complete recovery of dorsiflexion.

3. Discussion

A primary TKA for a valgus knee deformity of ＞20° represents a challenge for orthopedic surgeons.[12] Herein, we present our experience with a 63-year-old woman with a severe valgus knee deformity angle ＞90°, which was classified as a severe deformity. During surgery, we released the lateral collateral ligament soft tissues and excised the medial and lateral meniscus and the remaining cruciate ligament. A rotating hinge knee instrument was used to correct the bone axis and stabilize the joint. The use of hinged implants in primary TKA should be restricted to patients with severe bony deformities or ligamentous instability, especially in elderly patients.[14] Constrained implants are frequently used for primary TKA in patients with moderate and severe genu valgum (＞10°).[15] Constrained TKA is commonly performed to stabilize the joint and correct the bone axis in patients with severe ligamental instability, gross deformity, bone loss, and extreme deviation of the straight leg axis. In the present case, a rotating hinge knee prosthesis was selected.

外翻膝畸形＞20°的原发性全膝关节置换术对骨科医生来说是一个挑战[12]。在此，我们报告了一位63岁女性的经验，她的膝关节严重外翻畸形角度＞90°，被归类为严重畸形。在手术中，我们松解了外侧副韧带软组织，切除了内侧和外侧半月板以及剩余的交叉韧带。使用旋转铰链膝关节器械矫正骨轴并稳定关节。在原发性全膝关节置换术中使用铰链式植入物应仅限于严重骨畸形或韧带不稳定的患者，尤其是老年患者[14]。限制性假体常用于中度和重度膝外翻（＞10°）患者的初次TKA[15]。对于严重韧带不稳、严重畸形、骨质流失和直腿轴极度偏离的患者，通常采用限制性TKA来稳定关节和矫正骨轴。在本病例中，选择了旋转铰链膝关节假体。

A medial or lateral parapatellar approach can be used to perform TKA for valgus knee deformities. The lateral patellar incision is commonly used in mild-to-moderate valgus knee deformities to simply release the lateral structure. Given the position of the patella in the present case, the lateral parapatellar approach was not suitable to gain adequate exposure of the knee joint; thus, the medial parapatellar approach was used. Injury to the peroneal nerve is a common complication of TKA. The peroneal nerve injury is common when TKA is performed to correct valgus knee deformities, with an incidence of 2% to 3%.[16–19] We should pay more attention to the tension in the nerve, which could be alleviated by cutting off the fibular head, if necessary in osteotomy. Postoperatively, the knees were placed in 10° of flexion for 3 to 4 days to prevent stretching of the peroneal nerve, and active and passive range-of-motion exercises (range from 10° to 70°) were allowed.[20] In the present case, based on the preoperative evaluation of the surgical procedure, we believed that the peroneal nerve would not be transected, and thus we did not expose the peroneal nerve during the operation. However, postoperatively, the patient was unable to dorsiflex the ankle. Traction injury to the common peroneal nerve may result in the loss of ankle function. A traction injury to the common peroneal nerve was likely caused by straightening the knees. This complication could have been avoided by positioning of the knees in a flexed position after surgery and then gradually straightening the knees back out. Fortunately, the patient fully recovered 3 months after surgery.

内侧或外侧髌旁入路可用于外翻膝关节畸形的全膝关节置换术。髌骨外侧切口通常用于轻度至中度膝外翻畸形，以简单地松解外侧结构。考虑到本病例中髌骨的位置，外侧髌旁入路不适合获得足够的膝关节暴露;因此，我们采用内侧髌旁入路。腓神经损伤是TKA的常见并发症。在TKA矫正外翻膝关节畸形时，腓神经损伤是常见的，发生率为2% ~ 3%[16-19]。应注意神经紧张，必要时截骨可切除腓骨头缓解神经紧张。术后，膝关节屈曲10°3 - 4天，以防止腓神经拉伸，并允许主动和被动活动范围（10°至70°范围）锻炼[20]。在本病例中，基于术前对手术方法的评估，我们认为腓神经不会被横断，因此我们在手术中没有暴露腓神经。然而，术后患者无法踝关节背屈。牵引损伤腓总神经可导致踝关节功能丧失。牵拉伤腓骨总神经可能是伸直膝盖引起的。这种并发症可以通过手术后将膝关节置于弯曲位置，然后逐渐将膝关节拉直来避免。幸运的是，患者在手术后3个月完全康复。

Patellar dislocation or subluxation is a common finding in valgus knees. Patellar dislocation associated with congenital disorders appears to be classifiable into the following 3 types: conditions due to soft tissue laxity and increased joint laxity; conditions due to patellar hypoplasia and skeletal dysplasia of the femur and tibia; and conditions due to soft tissue fibrosis and contracture.[21] An abnormal patellar trajectory in the mild-to-moderate valgus knee can be corrected after knee arthroplasty.[22] In severe valgus conditions, the lateral patellar retinaculum, popliteus tendon, and the lateral portion of the gastrocnemius may require detachment to restore the anatomical axis of the limb. An anteromedial tibial tubercle transfer may be performed to correct patellar dislocation. In the present case, we corrected the severe abnormal patellar trajectory and tibial internal rotation by releasing the patellar lateral surface, vastus lateralis, and the intramuscular gap of the rectus femoris. A Z-shaped release of the biceps femoris was also performed. Since the patellar trajectory was still not completely corrected, we subsequently released the lateral collateral ligament by creating multiple needle punctures, incising the vastus lateralis, and extending it by malposed-suture to completely correct the patella trajectory.

髌骨脱位或半脱位是外翻膝的常见表现。与先天性疾病相关的髌骨脱位似乎可分为以下3种类型:由于软组织松弛和关节松弛增加引起的情况;髌骨发育不全，股骨和胫骨骨骼发育不良;以及软组织纤维化和挛缩引起的疾病[21]。轻度至中度外翻膝关节的异常髌骨轨迹可以在膝关节置换术后得到纠正[22]。在严重外翻的情况下，髌骨外侧支持带、腘肌肌腱和腓肠肌外侧部分可能需要脱离以恢复肢体的解剖轴。胫骨前内侧结节转移可用于矫正髌骨脱位。在本病例中，我们通过松解髌骨外侧面、股外侧肌和股直肌肌内间隙来纠正严重的异常髌骨轨迹和胫骨内旋。同时进行股二头肌Z形松解术。由于髌骨轨迹仍未完全矫正，我们随后通过多次穿刺从而松解外侧副韧带，切开股外侧肌，并通过错位缝合延长，以完全矫正髌骨轨迹。

In summary, in this rare case, we successfully performed TKA using a rotating hinge knee instrument for the treatment of a valgus deformity angle ＞90° associated with severe bony defects in the femur and tibia. The patellar dislocation was corrected without the use of anteromedial tibial tubercle transfer. Postoperatively, the patient experienced bilateral loss of ankle dorsiflexion due to a traction injury to the common peroneal nerve, which, however, was completely recovered in 3 months. Intraoperative exploration of the common peroneal nerve and postoperative flexed positioning of the knee joints could help prevent nerve injuries. However, since the hinge prosthesis was highly restricted, the lifetime of the prosthesis is a cause of concern. We still need to conduct long-term follow-ups of the patient.

总之，在这个罕见的病例中，我们成功地使用旋转铰链膝关节器械进行了TKA，治疗了角度＞90°的外翻畸形，并伴有股骨和胫骨的严重骨缺损。髌骨脱位不采用胫骨前内侧结节转移。术后，由于腓总神经牵拉损伤，患者双侧踝关节背屈丧失，但在3个月内完全恢复。术中探查腓总神经和术后膝关节屈曲定位有助于预防神经损伤。然而，由于铰链假体受到高度限制，假体的使用寿命是一个值得关注的问题。我们还需要对患者进行长期随访。