Bi Andrew S, Cole Wendell W, Lowe Dylan, Golant Alexander, Jazrawi Laith M
NYU Langone Orthopedics, Division of Sports Medicine, NYU Langone Orthopedic Center, New York, New York, USA.
Video J Sports Med. 2025 Jun 12;5(3):26350254241303551. doi: 10.1177/26350254241303551. eCollection 2025 May-Jun.
Isolated medial compartment knee osteoarthritis (OA) presents a challenging problem to treat for knee surgeons, with a multitude of options from conservative management, including injections and unloader braces, meniscal procedures, osteotomies, and unicompartmental knee arthroplasty (UKA). A new medial implantable shock absorber (MISHA) allows for offloading 142 N of the medial compartment during stance phase of gait.
US Food and Drug Administration approval was obtained on April 10, 2023, with the following indications: isolated medial knee OA (Kellgren-Lawrence grades I-IV) that failed 6 months of conservative management, ages 25 to 65 years, body mass index <35 or body weight <300 lbs, <15° of varus, no flexion contracture >10°, and no significant medial osteophytes or medial meniscal extrusion.
A longitudinal medial knee incision is made 1 cm proximal to the medial epicondyle to the pes insertion, around 3 cm medial to the tibial tubercle, exposing the superficial medial collateral ligament, and medial joint line. The establishment of the femoral anisometric point is critical to provide a 4-mm posterior condylar offset in 90° of flexion compared to full extension. A trial implant can be placed to confirm appropriate anisometry, implant loading in extension, and relaxation in flexion. The final implant is placed and the titanium femoral and tibial baseplates are fixed with 3 unicortical titanium locking screws each.
Expected results per recommended postoperative protocol are immediate weightbearing without range of motion restrictions. From author experience, patients typically feel improvement and return to sport more rapidly than with anterior cruciate ligament reconstructions. Recovery and return to work are faster than osteotomies or UKAs based on comparative short-term studies. While long-term results are lacking given the novelty of the procedure, prospective studies have demonstrated 100% arthroplasty-free survival at 2 years and 85% survival at 5 years.
DISCUSSION/CONCLUSION: The MISHA is a viable option for isolated medial compartment knee OA that provides a joint-preserving alternative to arthroplasty and a less morbid alternative to osteotomy. This treatment can be technically difficult to perform, but several pearls and techniques can offer a reproducible, minimally invasive surgery and good functional results.
The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.
孤立性内侧间室膝关节骨关节炎（OA）给膝关节外科医生带来了具有挑战性的治疗难题，有多种治疗选择，包括保守治疗，如注射和卸载支具、半月板手术、截骨术以及单髁膝关节置换术（UKA）。一种新型的内侧可植入减震器（MISHA）可在步态站立期卸载内侧间室142牛的力。
2023年4月10日获得美国食品药品监督管理局批准，适应症如下：经6个月保守治疗失败的孤立性内侧膝关节OA（凯尔格伦-劳伦斯分级I-IV级），年龄25至65岁，体重指数<35或体重<300磅，内翻<15°，无屈曲挛缩>10°，且无明显内侧骨赘或内侧半月板挤压。
在股骨内侧髁近端1厘米处至鹅足止点做一纵向内侧膝关节切口，位于胫骨结节内侧约3厘米处，暴露浅层内侧副韧带和内侧关节线。确定股骨非等距点对于在90°屈曲时比完全伸展时提供4毫米的后髁偏移至关重要。可放置试验性植入物以确认适当的非等距性、伸展时的植入物加载和屈曲时的松弛情况。放置最终植入物，并用3枚单皮质钛锁定螺钉分别固定钛制股骨和胫骨基板。
按照推荐的术后方案，预期结果是可立即负重且无活动范围限制。根据作者经验，与前交叉韧带重建相比，患者通常感觉改善更快且能更快恢复运动。基于比较性短期研究，恢复和重返工作比截骨术或单髁膝关节置换术更快。鉴于该手术的新颖性，虽然缺乏长期结果，但前瞻性研究表明2年时无关节置换生存率为100%，5年时生存率为85%。
讨论/结论：MISHA是孤立性内侧间室膝关节OA的一种可行选择，它为关节置换提供了一种保留关节的替代方案，为截骨术提供了一种创伤较小的替代方案。这种治疗在技术上可能难以实施，但一些技巧和技术可提供可重复的、微创的手术及良好的功能结果。
作者证明已获得本出版物中出现的任何患者的同意。如果个体可被识别，作者已随本提交的出版物包含患者的豁免声明或其他书面批准形式。
