Arthroscopic Artificial Meniscus Replacement 微創人工半月板替換

Dr. Adrian Leung > Arthroscopic Artificial Meniscus Replacement 微創人工半月板替換

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meniscus replacement

Background 背景

A badly torn meniscus beyond repair can be handled by arthroscopic artificial meniscus replacement.

There are two menisci in knee, Medial (inner) and Lateral (outer). They are C-shaped and fit between the Femur (thigh), which has a curved surface for rotation and the Tibia (shin), which has a flat platform. Apart from allowing surface contact rather than point contact (a curve on a flat surface), the meniscus also provide stability.

When the meniscus is torn, a common injury commonly happened when one sprains his knee, the stability of the knee will be compromised, and the knee will degenerate much quicker. There will be pain, and episodic swelling.

Repeated injury to the meniscus and further propagation of the tear is the expected natural course of the problem.

For patients who are young and active, arthroscopic repair is indicated. However, there are times when the tear is too extensive, or when the torn meniscus was removed previously hence inadequate material for repair.

Artificial meniscus (Patented product is called as Actifit™) is now available as commercial product, which stands test of time since its launch in 2009. Actifit™ is a polyurethane scaffold that allows human tissue to grow in. Once the cells forms a stable architect, the scaffold would be absorbed. The implantation can be done by minimal invasive technique.

After replacement, a period of protection is required before the meniscus regains its strength.

The followings are additional surgical procedures, addressing different concomitant pathologies,

  1. Partial meniscectomy
  2. Chondroplasty
  3. Microfracture
  4. Loose body removal
  5. Platelet Rich Plasma injection

人工半月板就是把撕裂的或缺失的半月板重建。

膝關節有兩塊C形的半月板，內側（內側）和外側（外側）。它們在表面有弧面的股骨（大腿）和表面是平面的脛骨（脛骨）之間。有了半月板，弧面跟平面就不再是點接觸（曲線跟平面的接觸）而是整個表面的接觸之外。此外，半月板還增加了膝關節的穩定性。

半月板撕裂是一種膝關節扭傷時常見的結構受損。半月板撕裂會令膝關節的穩定性降低，所以膝關節會經常再扭傷，撕裂會越來越大，其他結構也會受影響，包括軟骨。而且，由於膝關節的接觸面積會大大減少，導致壓力過大，所以膝關節的退化速度會越來越快。期間會出現疼痛和水腫積液。

對於年輕或生活比較活躍的患者，一般會建議進行關節鏡下修復。不僅有助改善功能，減少疼痛和腫脹，而且也可能減緩退化過程。但如果破壞情況嚴重，或之前已被切除，要修復就需要使用其他形式。以往需利用過身者捐的半月板，但自2009年，聚氨酯人工半月板(專利產品叫做Actifit™)已經推出市場。Actifit™ 由高度連結和多孔的合成物質組成，人體組織細胞可以誘導在其內生長。隨著時間過去，半月板狀的組織成形，植入的Actifit™支架結構會慢慢分解。臨床追蹤研究顯示效果理想。

通過微創技術植入人工半月板已是標準程序。開大刀十分罕見。

重建後，半月板恢復正常強度之前，需要一段時間保護，避免負重走路，所以需要使用手仗，但絕少需要配戴支架。

以下是針對不同同時出現的傷患而附加的外科手術程序，

正常半月板 normal meniscus
植入人工半月板 Implantation of Actifit

Indication 適應症

  • Meniscus defect, sizable, anterior horn, body, and posterior horn 半月板大範圍缺失，前角，中位和後角
  • Medial Meniscus tear, middle and inner zone, anterior horn, body, and posterior horn 內側半月板撕裂，中部中央區域，前角，中位和後角
  • Lateral Meniscus tear, middle and inner zone, anterior horn, body, and posterior horn 外側半月板撕裂，中部中央區域，前角，中位和後角

Preparation 預備

  • Pre-op workup 手術前身體檢查
  • Walking >10000 steps a day 堅持每天1萬步強化背及腿肌
  • Do more deep breath 多深呼吸
  • Continue usual medication on operative day 手術當天照常食藥
  • No food or drink for 6 hours 手術前6小時禁食及禁喝水
  • Admit to hospital 3 hours before surgery  手術前3小時到醫院
  • Inform your relative despite surgery takes less than 2 hours, you will return no earlier than 3 hours. 通知家人即使手術只需2小時，但回病房可能是3小時後

Risk 風險

While all medical and nursing professionals endeavor to provide best and safest practice, complications still would occur.
General operative risks including heart attack, stroke, wound infection, wound hemorrhage, urinary tract infection, deep vein thrombosis, scar pain, unsightly scar, wound gapping and even failure to heal, etc, is possibly encountered.

Nerve and vascular injury are rarely occurred risk but can be catastrophic with paralysis, loss of sensation and even limb loss. Anatomical variants also carry more risk.

Persistent lack of healing and instability is around 16%. Therefore, early protection and avoid enthusiastic stretching and weight bearing in early stage is important.

儘管醫生和護士都會盡最大努力提供最佳和最安全的治療，但併發症仍會發生。

一般手術可能會遇到的風險，包括心臟病發作，中風，傷口感染，傷口出血，尿道感染，深層靜脈血栓形成，傷口疼痛，外觀不理想甚或傷口不癒等，這手術也不例外。

神經及血管損傷是很少遇上，但可導致災難性癱瘓，失去知覺甚至截肢。先天結構異常也會有更高的風險。

持續不癒或不穩大概為16%。所以早期保護及避免太早活動及受力尤其重要。

Budget Estimation 預算費用 (Hong Kong 香港)

CPT code and RVU is as follows

  • 29883, Arthroscopically aided meniscus repair (medial AND lateral), RVU 11.77
  • 29882, arthroscopy, knee, surgical; with meniscus repair (medial OR lateral), RVU 9.63
  • 29881 partial menisectomy, RVU 7.03
  • 29877 chondroplasty, RVU 8.3
  • 29879 Microfracture, RVU 8.99

CPT碼和RVU如下

  • 29883　關節鏡半月板修復（內側及外側），RVU 11.77
  • 29882　關節鏡半月板修復（內側或外側），RVU 9.63
  • 29881　半月板切除術，RVU 7.03
  • 29877　軟骨打磨，RVU 8.3
  • 29879　微骨折，RVU 8.99

Estimation based on general ward as in Aug-2020,

  • Surgeon fee $38,520 (1 meniscus), $47,080 (both meniscus)
  • Anaesthetist fee $19,066 (1 meniscus), $15,693 (both meniscus)
  • Ward round $1,200/day
  • Hospital charge $60,000 (1 meniscus), $68,000 (both meniscus)

Total $119,986 (1 meniscus), $133,173 (both meniscus) around

根據普通房於2020年8月進行的估算，

  • 外科醫生費$38,520 (單伴月板修復), $47,080 (兩邊伴月板修復)
  • 麻醉師費 $19,066  (單伴月板修復), $15,693 (兩邊伴月板修復)
  • 巡房費$1,200
  • 醫院費$60,000  (單伴月板修復), $68,000 (兩邊伴月板修復)
  • 總計 $119,986  (單伴月板修復), $133,173 (兩邊伴月板修復)左右

Reference figures from private hospitals　醫院提供的參考數據

St Paul’s Hospital 聖保祿醫院

Median Charge 收費中位數　

  • Doctors’ fee 醫生費 Not provided 未提供
  • Hospital charge 醫院收費 Not provided 未提供
  • Total 總費 Not provided 未提供

Reference website

Cannosa Hospital 嘉諾撒醫院

Median Charge 收費中位數

  • Doctors’ fee 醫生費 Not provided 未提供
  • Hospital charge 醫院收費 Not provided 未提供
  • Total 總費 Not provided 未提供

Reference website

Baptist Hospital 浸會醫院

Median Charge 收費中位數

  • Doctors’ fee 醫生費 Not provided 未提供
  • Hospital charge 醫院收費 Not provided 未提供
  • Total 總費 Not provided 未提供

Reference website

Adventist Hospital 港安醫院

Median Charge 收費中位數

  • Doctors’ fee 醫生費 Not provided 未提供
  • Hospital charge 醫院收費 Not provided 未提供
  • Total 總費 Not provided 未提供

Reference website

Post-op care 術後照顧

  • Control inflammation with regular usage of anti-inflammatory drug.
  • Apply cool pad (not ice pad) to the knee 30min 3 times a day.
  • If you have Cool-Pulse, use it as instructed.
  • Keep the knee above chest (sleep with 2 pillows supporting the calf, lie on floor and put calf on chair)
  • Tighten up your thigh and calf muscle 10 repetitions every 2 hours when you are awake.
  • Push the knee back against a flat and hard surface to straighten it, to prevent joint contracture.
  • You need to walk with crutches all the time and avoid weight bearing, including at home and indoor.
  • Stay home for first 3 days. Do not walk more than 3000 steps in first 6 week, gradually increase to not more than 6000 steps a day in 8 weeks time.
  • Wear a hinged knee brace. First 6 weeks 0-45°; 7-12 weeks up to 90°
  • Walk with no weight bearing in first 6 weeks; 7-8 weeks half body weight; 9 weeks onward full weight bearing
  • Standing with full weight since Day 1 post-op
  • The wound is covered by a waterproof dressing. After 2 weeks, you can shower after carefully remove the boot temporarily, but do not take bath or rub on it. Keep the dressing intact, there is no need to change it regularly.
Actifit™ 人工半月板
  • 定時服藥，控制發炎
  • 每天3次在膝蓋上敷涼墊（不是冰墊）30分鐘。
  • 如果您有Cool-Pulse，請按照指示使用它。
  • 將腳放高於胸部（躺下時用2個枕頭抬高小腿；平時躺在地上，將小腿放在椅子上）
  • 當不是睡覺時，每2小時收緊大腿和小腿肌肉10次。
  • 將膝蓋向後壓到平而堅硬的表面．例如窗台，避免關節萎縮。
  • 任何時候都必須使用拐杖及避免負重，包括在家中或室內環境。
  • 手術後頭三天要留家休息。第六周不要走超過3000步，在隨後兩周週逐漸增加到每天不超過6000步。
  • 配戴膝關節護架。活動範圍：首6週：0 – 45°；第6-12週：90°
  • 步行：首6週：不能負重；第6- 8週：半負重；第9週：完全負重
  • 站立：首1天已可全負重
  • 傷口已用防水敷料覆蓋。所以2星期後，您可以脫下固定靴淋浴，但不要浸澡或捽這敷料。你只需保持敷料完整，無需定期更換它。

Early Post-op Complication　手術後早期併發症

Notify surgeon in case you have

  • Persistent fever of more than 37.5 Celcius
  • Chills and rigor
  • Wound pain despite rest
  • Wound redness and swelling
  • Purulent discharge from wound
  • Calf pain
  • Ankle swelling, progressive
  • Sudden onset of shortness of breath
  • Chest pain

如發現以下情況，要立即通知醫生

  • 持續高燒（口探高於攝氏37.5度）
  • 發冷打顫
  • 無論運動或休息時，傷口痛楚都持續增加
  • 傷口持續發紅腫脹
  • 傷口有膿液
  • 小腿愈見痛楚
  • 小腿、腳踝和腿部腫脹持續增加
  • 突發性的氣促
  • 胸口突然疼痛

Rehabilitation after Day 14 手術後2週復健

Exercise of calf and thigh muscles:

  1. Quadriceps contraction:
    Sit on chair, straighten the knee, count 15 seconds, and then relax. Rest for 10 seconds and repeat 10 times.
    When you have regained strength, wall sitting at 45 degrees knee flexion, hold 90 seconds, with interval rest, 10 repetitions, 4 times a day. Need to use upper limb to support the descend.
  2. Calf contraction:
    Sit on chair, tighten your calf muscle, count 15 seconds, and then relax. Rest for 10 seconds and repeat 10 times.
    When you have regained strength, do tip toe standing, hold 90 seconds, with interval rest, 10 repetitions, 4 times a day

Range of Motion exercise:

  • Put the foot on floor, slide the foot backward on floor, to increase knee bending angle, with 45° limit.
  • Continue stretching exercise to ensure the knee is straight. You can compare to the normal side.

Further strengthening and return to sports:

  • You can sit in the office for a long hours in 3 weeks after the operation, and go running no earlier than 4 months.
  • Increase the amount of activity gradually and avoid strenuous exercise, especially running, kicking and jumping.
  • Sex life can start at 6 weeks after surgery.
  • Avoid excessive knee fatigue within one year.

小腿和大腿肌肉的運動:

  1. 大腿四頭肌收縮：
    坐在椅子上，全神貫注下伸直膝蓋，保持伸直並數15秒，然後放鬆。休息10秒鐘，重複10次。
    肌力漸恢復後，以上肢支撐慢慢到45°倚牆淺蹲，保持90秒，間隔休息，重複10次，每天4次。
  2. 小腿收縮：
    坐在椅子上，收緊小腿肌肉，數15秒鐘，然後放鬆。休息10秒鐘，重複10次。
    肌力漸恢復後，做趾尖企，保持90秒，間隔休息，重複10次，每天4次。
  1.  

運動範圍：

  1. 將腳放到地板上，慢慢拉回，以增加膝屈曲角度到45°。
  2. 繼續壓膝，避免膝關節萎縮。

進一步加強肌力並重返正常運動：

  1. 您可以在手術後3週返回辦公室坐較長時間。需超過4個月才開始跑步。
  2. 逐漸增加運動量，避免劇烈運動，尤其是跑步，踢腿和跳躍。
  3. 性生活可以在手術後6週開始。
  4. 一年內避免膝關節過度疲勞。

Reference 參考文獻

  1. Verdonk PCM, Van Laer MEE, Verdonk R. Meniscus replacement: from allograft to tissue engineering. Sports Orthop Traumatol
    2008;24(2):78–82.
  2. Verdonk R, Verdonk P, Huysse W, Forsyth R, Heinrichs E. Tissue in-growth after implantation of a novel, biodegradable polyurethane scaffold for treatment of partial meniscal lesions. Am J Sports Med 2011;39(4):774–82
  3. C Baynat, C Andro, J P Vincent, P Schiele, P Buisson, F Dubrana, F X Gunepin. Actifit synthetic meniscal substitute: experience with 18 patients in Brest, France.Orthop Traumatol Surg Res. 2014 Dec;100(8 Suppl):S385-9.
    doi: 10.1016/j.otsr.2014.09.007. Epub 2014 Oct 25.
  4. eroy A, Beaufils P, Faivre B, Steltzlen C, Boisrenoult P, Pujol N. Actifit polyurethane meniscal scaffold: MRI and functional outcomes after a minimum follow-up of 5 years. L Orthop Traumatol Surg Res. 2017 Jun;103(4):609-614. doi: 10.1016/j.otsr.2017.02.012. Epub 2017 Apr 1.