Endoscopic shelf acetabuloplasty can improve clinical outcomes and achieve return to sports-related activity in active patients with hip dysplasia
鏡視下Shelf臼蓋形成術は、 臼蓋形成不全(寛骨臼形成不全)を有する活動性の高い患者らにおいて、臨床的Outcomesを改善し、スポーツ関連活動の復帰の達成を可能とする。

Soshi Uchida1 ・ Akihisa Hatakeyama2 ・ Shiho Kanezaki1 ・ Hajime Utsunomiya4 ・ Hitoshi Suzuki1 ・ Toshiharu Mori2 ・Angela Chang4 ・ Dean K. Matsuda3 ・ Akinori Sakai2
Department of Orthopaedic Surgery, Faculty of Medicine, Wakamatsu Hospital of the University of Occupational and Environmental Health, 1‑17‑1, Hamamachi, Wakamatsu, Kitakyushu, Fukuoka 808‑0024, Japan
Knee Surgery, Sports Traumatology, Arthroscopy 2017


Purpose To investigate clinical outcomes and return to sports-related activity following endoscopic shelf acetabuloplasty combined with labral repair in the treatment of the active patients with developmental dysplasia of the hip (DDH).
Methods Between 2011 and 2013, 32 patients (36 hips; 11 males and 21 females; 11 right 17 left 4 bilateral; median age 28.5, range 12-51 years), who underwent endoscopic shelf acetabuloplasty combined with labral repair and met the inclusion criteria were enrolled in this study. There was a minimum follow-up of 2 years (average 32.3 ± 3 months, range 24-48 months). Patient-reported outcome (PRO) scores including the modified Harris Hip Score (MHHS) and Non-Arthritis Hip Score
(NAHS) were obtained preoperatively and at final follow-up for the assessment of surgical outcomes.

Results The mean MHHS significantly improved from 68.4 ± 14.3 (range 23.1-95.7) preoperatively to 94.5 ± 8.5 (range 66-100) at final follow-up (p = 0.001). Similarly, the NAHS also significantly improved from 51.3 ± 11.9 (range 23-76) preoperatively to 73.0 ± 7.4 (range 44-80) at final follow-up (p = 0.001). The mean LCE angle significantly increased postoperatively but partially decreased at final follow-up (mean preoperative versus postoperative versus final follow-up: 16.0 range 5-24, versus 40.1 range 27-58, versus 30.1 range 20-41. p = 0.001, respectively). There were 3 patients who returned to a higher activity level, 20 patients who returned to the same activity level, and 6 patients who returned to a lower activity level. The mean period from surgery to return to play was 9.0 ± 3.5 months (range 5-18).
結果:平均MHHSは、術前の68.4±14.3点(範囲23.1-95.7)から最終経過観察時の94.5±8.5点(範囲66-100)に有意に改善された。同様に、NAHSも、術前の51.3±11.9点(範囲23-76)から、最終経過観察時の73.0±7.4点(範囲44-80)に有意に改善された。平均LCEAは、術後に有意に増加したが、最終経過観察(平均術前 vs 術後 vs 最終経過観察:16.0度[範囲5-24] vs 40.1度[範囲27-58] vs 30.1度[範囲20-41])において一部減少が認められた。3患者が、より高い活動レベルに復帰し、20患者が同じ活動レベルに復帰し、そして6患者がより低いレベルの活動に復帰した。手術から競技復帰までの平均期間は9.0±3.5ヶ月(範囲5-18)であった。

Conclusion Endoscopic shelf acetabuloplasty provides promising clinical outcomes and return to sports-related activity for active patients with DDH.
Level of evidence:Level IV.
Keywords Hip arthroscopy ・ Developmental dysplasia of the hip ・ Acetabular labral tear ・ Shelf acetabuloplasty ・ Return to Sport

Developmental dysplasia of the hip (DDH) is a rare cause of hip pain in the US but is one of the most common sources of hip pain in young active patients in the Asian population. Active patients especially athletes with DDH typically experience frequent groin and lateral hip pain associated with intra-articular pathology including acetabular labral tear and cartilage damage [25].

There is disparate evidence for and against hip arthroscopy in the setting of DDH. Emerging evidence suggest that Cam deformities often co-exist with DDH [30]. While the mildest forms of DDH (borderline) may respond favorably to isolated hip arthroscopy with femoroplasty and labral and capsular repairs, mild to moderate DDH may have less successful outcomes in the short-term[7, 8, 15, 19]

Previous studies established hip arthroscopy as a beneficial technique for treating mild DDH [3, 17, 33]; however, the recent literature reports a high reoperation rate and lateral migration with conversion to total hip arthroplasty [13, 24]. One study advise against performing hip arthroscopy for DDH when a broken Shenton line, a femoral neck shaft angle > 140°, and lateral center edge (LCE) angle < 19° are observed, or when severe cartilage damage is present at the time of surgery [30]. Rotational acetabular osteotomy (RAO) and periacetabular osteotomy (PAO) are beneficial procedures for treating patients with DDH, especially moderate and severe forms [9, 20]. However, high-demand athletes with DDH are not good candidates for these conventional approaches including PAO or RAO because of prolonged postoperative rehabilitation and unestablished ability to return to sport [5, 6].
以前の研究は、軽度DDHの治療に対する有効なテクニックとして股関節鏡を確立した;しかしながら、最近の文献は、高い再手術率とTHAの移行を伴う外方化を報告する。1研究は、Shenton lineの破綻、140度以上のfemoral neck shaft angle及び19度未満のLCEAが観察されるとき、または重度の軟骨損傷が手術時に存在するとき、DDHに対して股関節鏡を実施しないほうが良いことを助言する。RAO及びPAOは、特に、中等度及び重度のDDHを有する患者らの治療に対して有効な手技である。しかしながら、DDHを有する要求度の高いアスリートは、長期の術後リハビリテーションとスポーツ復帰に対する未確立の能力に起因して、PAOまたはRAOを含めたこれらの伝統的アプローチ法に対する良好な候補者とはならない。

Uchida et al. described new shelf acetabuloplasty endoscopic technique with arthroscopic chondrolabral and capsular reparative surgery to better access and address osseous anterolateral coverage [31]. This minimally invasive procedure is associated with less postoperative morbidity and has a greater potential to enable athletes to return to high functioning activities. It was hypothesized that symptomatic active patients with hip dysplasia can benefit from endoscopic shelf acetabuloplasty. The purpose of this study was to investigate the clinical outcomes and return to sports activity after endoscopic shelf acetabuloplasty combined with Cam osteoplasty with labral and capsular repairs.
Uchidaらは、前外側骨性被覆をより良好にアクセスし対処するために、鏡視下軟骨関節唇修復術と関節包修復術を伴う新しい鏡視下Shelf臼蓋形成術を詳細した。この最小侵襲手技は、より少ない術後morbidityに関連され、アスリートの高機能活動の復帰を可能にするより大きな潜在性を有する。股関節形成不全を有する症候性の活動性の高い患者らは、鏡視下Shelf臼蓋形成術から利点が得られる可能性があると仮説が立てられた。本研究の目的は、関節唇修復及び関節包修復術とCam osteoplastyと組み合わされた鏡視下Shelf臼蓋形成術後の臨床Outcomesとスポーツ活動の復帰を調査することにあった。

If this surgery provides clinical benefit to athletic patients that might otherwise require open RAO/PAO, it could establish endoscopic shelf acetabuloplasty as a viable less invasive surgery extending to the active patient population.
もし、Open RAO/PAOを必要とする可能性があったアスリート患者に対して、この手術が臨床的利点を提供するなら、活動性の高い患者集団にまで延長する、実行可能な低侵襲手術として、鏡視下Shelf臼蓋形成術を確立できるものと考える。

Materials and methods

The medical records of 80 patients (86 hips) who underwent endoscopic shelf acetabuloplasty by a single surgeon
(S.U) between 2011 and 2013 were retrospectively reviewed. Endoscopic shelf acetabuloplasty were indicated for symptomatic DDH (Fig. 1), defined as recalcitrant pain in hip and/or groin unresponsive to conservative treatment for a minimum of 3 months (e.g., NSAIDs, modification of painful sports and/or hip flexion-related activities, physical therapy), a lateral center edge (LCE) angle of Wiberg of less than 25° [32] on pelvic anterior-posterior view (AP) and/or vertical-center-anterior (VCA) angle of less than 20° on false profile view [16] (Fig. 2a, b), positive provocative maneuvers (anterior impingement and/or FABER tests), and intra-articular pathology including acetabular labral tears as detected by a gadolinium-enhanced magnetic resonance (MR) arthrogram (Fig. 2c).
2011年から2013年までの期間に、単一術者(S.U.)によって鏡視下Shelf臼蓋形成術を受けた80患者(86股)の医療記録が、後ろ向きに調査された。鏡視下Shelf臼蓋形成術は、3ヶ月間の保存療法(すなわち、NSAIDs、有痛性スポーツ及び/または股関節屈曲に関連される活動の修正、理学療法)に抵抗し、AP骨盤レントゲン上で25度未満のWibergのLCEA、及び/またはfalse profile view上の20度未満のVCA、陽性の疼痛誘発テスト(anterior impingement及び/またはFABERテスト)、及びガドリニウム造影MRA(図2c)によって検出される股関節唇断裂を含めた関節内病変として定義された症候性DDH(図1)に対して適用された。

Contraindications for hip arthroscopy in DDH included osteoarthritis (Tonnis grade II and III), Legg Calve Perthes disease, and lateral migration of the femoral head. A total of 36 hips were excluded; 13 of these hips belonged to non-athletes. Patients with either ankle lateral ligament instability (n = 2), knee osteoarthritis (Kellgren and Lawrence classification osteoarthritis grade 3 and 4) (n = 2), history of a previous hip surgery (n = 8), lumbar spine disorder (n = 3), worker compensation (n = 3), history of motor vehicle accident (n = 3) or Welfare recipients (n = 2) were excluded. 12 non-athlete hips were excluded. Two patients (two hips) were lost to follow-up.
DDHの股関節鏡に対する禁忌には、OA(Tonnisグレード教擇哭掘法ペルテス病、及び大腿骨頭の外方化が含まれた。合計36股が除外された:これらのうち13股が非アスリートに属した。どちらかの足関節の外側靭帯不安定性を有する患者(n=2)、膝OA(Kellgren and Lawrence分類のグレード3及び4のOA)を有する患者(n=2)、股関節の手術歴(n=8)、腰椎疾患(n=3)、労災補償(n=3)、自動車事故(n=3)または生活保護受給者(n=2)の患者は除外された。非アスリートの12股が除外された。2患者(2股)が経過観察をロストした。

Thirty-two patients (36 hips, 11 males and 21 females), who participated in competitive sports, met our inclusion criteria and were enrolled in this study (Fig. 1). Patients were defined as active patients based on the University of California-Los Angeles Activity Scale (UCLA-AS) score of ≥7. We also defined active patients as those who play at least one organized sport in formal competition. There were three in baseball, three in dance, two in badminton, two in ballet, two in track and field, two in climbing, two in Judo, two in rhythmic gymnastics, two in basketball, two in running and one each in table tennis, swimming, karate, cycling, rugby, kyudo, volleyball and baton twirling.

All our patients had adequate self-reported participation in sports that met both criteria at the time of injury.
Surgical outcomes were obtained and assessed for 32 patients (36 hips, 11 males and 21 females 15 right hips and 13 left 4 bilateral hips). The mean BMI at the time of surgery was 21.8 (16.9-26.4). The median age at the time of surgery was 28.5 years old (range 12-51 years). There was a minimum follow-up of 2 years (average 32.3 ± 3 months, range from 24 to 48) (Tables 1, 2).

Radiographic evaluation
The preoperative radiographs of the 32 patients (36 hips) were assessed. All radiographic measurements were manually assessed by two authors using picture archiving and communication system (PACS) A.K and S.K. We determined the LCE angle, the Tonnis angle, the femoral neck shaft (FNS) angle, the presence or absence of a broken Shenton line on pelvic AP view, the VCA angle on false profile view, and alpha angle on cross-table lateral view or modified Dunn view (Fig. 2a-c) [16, 22, 32]. The alpha angle reflects the amount of Cam deformity and is measured by drawing a line parallel to the femoral neck to the center of the femoral head and a concentric circle is then drawn around the femoral head. A second line is drawn from the center of the concentric circle around the femoral head to the point at which the femoral head-neck junction falls outside of the concentric circle. The angle subtended between these lines is the alpha angle.
32患者(36股)の術前レントゲンが評価された。全てのレントゲン計測は、PACSを用いて著者の2人(A.K及びS.K)によって徒手的に評価された。我々は、AP骨盤画像上で、LCEA、Tonnis angle、FNS angle、Shenton lineの破綻の有無を、false profile view上でVCA、そしてcross-table lateral viewまたはmodified Dunn view上でαアングルを判定した(図2a-c)。αアングルは、Cam変形の量に応答するものであり、大腿骨頭と大腿骨頚部の中心に対して平行線が引かれ、それから、大腿骨頭周囲に同心円が描かれることによって計測される。2本目の線が、大腿骨頭周囲の同心円の中心から、同心円の外に逸脱した大腿骨頭頚部移行部のポイントまで引かれる。これらの線の間の角度がαアングルとなる。

A Cam deformity is defined by an alpha angle greater than 55° on plain radiograph (Fig. 2c) [22]. All preoperative and yearly postoperative radiographs for osteoarthritic changes were evaluated using the Tonnis osteoarthritis grade classification system [29]. The inter-observer and intra-observer reproducibility of these radiographic parameters were investigated. For inter-observer reliability, two hip surgeons (A.K and S.K) blinded to the clinical data and details of radiology reports, independently measured each radiograph.
Cam変形は、単純レントゲン上で55度以上のαアングルとして定義された(図2c)。OA変化に対して、全ての術前及び毎年の術後レントゲンが、Tonnis OAグレード分類を用いて評価された。これらのレントゲンパラメータの検者間及び検者内再現性が調査された。検者間信頼性に対して、臨床データとレントゲン報告の詳細に対して盲検化された2人の股関節外科医(A.K及びS.K)が独立して、各レントゲンを計測した。

For intra-observer reliability, one hip surgeon (A.K) individually measured radiographs at three separate times, with at least 1 week between measurements. Inter-class correlation coefficients (ICCs) and corresponding 95% confidence intervals (CIs) were calculated to quantify inter-observer and intra-observer reliability for continuous variables.

The weighted kappa value was used to determine agreement between two surgeon observation for a broken Shenton line and Tonnis osteoarthritis classification for hip dysplasia. Kappa values and ICCs of 1.0 are indicative of perfect agreement. The strength of agreement was interpreted as follows: ICC greater than 0.8 indicated almost perfect agreement; ICCs of
0.61-0.80, substantial agreement; ICCs of 0.41-0.60, moderate agreement; and ICCs of 0.21-0.40, fair agreement.
加重κ値が、股関節形成不全に対するShenton lineの破綻とTonnis OA分類に対して、2人の外科医間の一致性を判定するために用いられた。1.0のκ値及びICCsが完全一致を示唆する。一致の強度は、次のように解釈された:0.8以上のICCsが、ほぼ完全一致;0.61-0.80のICCsがsubstantial一致;0.41-0.60のICCsがmoderate一致;そして0.21-0.40のICCsがfair一致。

Based on the standards for the kappa statistic proposed by Landis and Koch, our measurements were in substantial agreement to the Tonnis osteoarthritis classification system [14]. At the preoperative examination, the mean LCE angle was 16° ± 4.8° (range 5-24), the mean Sharp angle was 47.9° ± 3.7° (range 43-58), the mean Tonnis angle was 15.3° ± 6.3° (range 1.6-34.0), the mean alpha angle was 65° ± 16.8° (range 47-98), and mean VCA angle was 18° ± 6.8° (range − 3 to 24).
LandsとKochによって対案されたκ統計の標準値に基づいて、我々の計測は、Tonnis OA分類に対してsubstantial一致であった。術前検査において、平均LCEAは、16±4.8度(範囲5-24)、平均Sharp角は47.9±3.7度(範囲43-58)、平均Tonnis angleは15.3±6.3度(範囲1.6-34.0)、平均αアングルは65±16.8度(範囲47-98)、そして平均VCAは18±6.8度(範囲マイナス3から24)であった。

Surgical technique
Supine hip arthroscopy was performed on a traction table under general anesthesia. Anterolateral, mid-anterior and proximal mid-anterior portals (ALP, MAP and PMAP) were created. Inter-portal capsulotomy was performed. Intra-articular pathologies including acetabular chondrolabral damage and femoral head chondral damage were assessed and documented (Fig. 3a). Microfracture chondroplasty was performed if ICRS grade III or IV chondral defects were present.
仰臥位の股関節鏡が、全身麻酔下の牽引テーブル上で実施された。ALP、MAP及びPMAPが作成された。ポータル間関節包切開が実施された。寛骨臼軟骨関節唇損傷及び大腿骨頭軟骨損傷を含めた関節内病変が評価され記録された(図3a)。Microfracture chondroplastyが、ICRSグレード靴泙燭廊犬瞭霍欠損が存在した場合に実施された。

Next, unstable labral tears were addressed with midsubstance repair following conservative rim trimming using a motorized burr to create a bleeding bone surface. Midsubstance labral repair was performed using bioabsorbable suture anchors (OsteoRaptor, Smith & Nephew, Andover, MA or Gryphon BR, Depuy Mitek Sports, Raynam MA) with knots tied on the capsular side of the labrum [27] (Fig. 3b). Arthroscopic dynamic examination was performed to assess for Cam impingement.
次に、不安定性関節唇断裂が、出血母床を作成するためにシェーバーバーを用いた温存的rim trimming後に、実質部修復を用いて対処された。実質部関節唇修復術は、関節唇の関節包側上に結び目を配置し、吸収性スーチャーアンカーを用いて実施された(OsteoRaptor, Smith & Nephew, Andover, MA or Gryphon BR, Depuy Mitek Sports, Raynam MA)(図3b)。鏡視下動的評価が、Camインピンジメントを評価するために実施された。

When necessary, Cam osteochondroplasty using a motorized round burr was performed. Following Cam impingement evaluation and repair, capsular closure was performed with the hip at 40° of flexion via the MAP and PMAP. Typically three to five stitches with extra-capsular knots were used for capsular plication (Fig. 2c, d) [31].
必要に応じて、シェーバーバーを用いたCam osteochondroplastyが実施された。Camインピンジメントの評価及び修復、関節包の閉鎖が、MAP及びPMAPを介して、股関節屈曲40度で実施された。関節包外の結び目を用いて、通常、3-5本のスティッチが関節包プリケーションのために用いられた(図3c、d)。

Endoscopic shelf acetabuloplasty was then performed as described previously [31]. A 30° arthroscope was positioned into the extra-capsular space under the guidance with fluoroscopic imaging. After identifying the straight head and reflected head of the rectus femoris and debriding the latter with a shaver and radiofrequency ablator, two parallel 2.4-mm guide-wires were introduced using the drill guide through the MAP, along the anterior acetabular rim adjacent to the capsule (Fig. 3e, f).

The slot was enlarged with the use of 10-mm osteotome to measure approximately 5-6 mm in height, 25 mm in width and at least 20 mm in depth. The optimum width and depth were confirmed using a custom-made dilator (Fig. 3g, h). Autologous tri-cortical bone graft (tri-cortical) harvested from the ipsilateral iliac crest (Fig. 3i).
溝が、高さ約5-6mm、幅25弌△修靴鴇なくとも20mmの深さを計測するために、10mmのノミを用いて拡大された。最適な幅と深さが、カスタム製ダイレーターを用いて確認された(図3g、h)。自家tri-cortical boneグラフト(tri-cortical)が同側の腸骨稜から採取された(図3i)。

Two 1.5 mm Kirshner wires were introduced in 1.8 mm-diameter drill holes, helping to control the graft position during endoscopic insertion into the aforementioned anterolateral periacetabular slot (Fig. 3i). Finally, the free bone graft was secured into the appropriate position, with cortical surface facing the femoral head in intimate contact with the intervening capsule, using a press-fit technique with a cannulated bone tamp (Smith & Nephew, Japan) (Fig. 3j). Corticocancellous bone chips were inserted above the new shelf under endoscopic guidance.
2本の1.5mm Kワイヤーが、前述の前外側寛骨臼周囲溝内に鏡視下で挿入時のグラフトの配置を制御することを支援するために、1.8mm径のドリルホール内に挿入された。最後に、free boneグラフトが、キャニュレイテッドbone tamp(Smith & Nephew, Japan)を用いたpress-fitテクニックで、介在する関節包と密接に接触する大腿骨頭に面した皮質面を伴い、適切な配置に固定された(図3j)。皮質海綿骨チップが、鏡視ガイダンス下で、新たなShelf上に挿入された。

Figure 2EH

Figure 2IJ

Postoperative management and rehabilitation protocol
Patients were instructed to remain non-weight bearing for the first 3 weeks. During this time, the patients were provided a brace for 3 weeks to limit hip ROM. Passive ROM exercises were initiated during the first week by physical therapists. Circumduction exercises were performed for the first 2 weeks to avoid adhesive capsulitis.

Patients were allowed to participate in normal activities of daily living over a 2-month postoperative period. Patients resumed to physical activity once maximized ROM and stable gait were achieved over a 3-month postoperative period. Intra-articular pathologies, including labral tearing, ligamentum teres and chondral damage were also evaluated according to the Multicenter Arthroscopy of the Hip Outcomes Research Network (MAHORN) classification of acetabular rim lesions, as well as cartilage damage at femoral head according to the international cartilage research society (ICRS) classification [26].

Patients completed detailed patient-reported outcome (PRO) scores including the modified Harris Hip Score (MHHS; of a possible 100 points) [2], the Non-Arthritis Hip Score (NAHS; of a possible 100 points) [4] and International Hip Outcome tool (iHot-12; of a possible 100) [11]. Patient's athletic activity was also quantified according to the UCLA-AS guidelines (Table 1) [34]. The institutional review board (IRB) approved the study and all study subjects were provided informed consent (University of Occupational and Environmental Health, Approve number: H28-095).
患者らは、MHHS、NAHS、及びiHOT-12を含めたPROスコアを完成した。また、患者らのスポーツ活動性が、UCLA-ASガイドラインに応じて定量化された(表1)。研究はIRBから承認され、全ての研究対象は、インフォームドコンセントが提供された(産業医科大学, Approve number: H28-095)。

Statistical analysis
Statistical analyses about clinical outcomes and radiographic parameters of all 32 patients were performed using the SPSS (version 13, SPSS Inc., Chicago, IL, USA) software package. Power analysis was conducted using G*Power (ver. 3.1, Universitat Dusseldorf, Dusseldorf, Germany). An α error was set 0.05, and a 1 − β error was set 0.80. Wilcoxon signed-rank test was used to compare paired nonparametric data and the Mann-Whitney U test was used to analyze nonparametric paired data. A p value of 0.05 or less was considered statistically significant.
全32患者の臨床Outcomes及びレントゲンパラメータについての統計解析はSPSSソフトウェアパッケージ(version 13, SPSS Inc., Chicago, IL, USA)を用いて実施された。検出力解析は、G*Power(ver. 3.1, Universitat Dusseldorf, Dusseldorf, Germany)を用いて実施された。αエラーは0.05に設定され、1−βエラーは0.80に設定された。Wilcoxon signed-rank検定は、paired nonparametricデータを比較するために用いられ、そして、Mann-Whitney U検定は、nonparametric pairedデータを解析するために用いられた。P値0.05未満が統計学的有意とみなされた。
Power analysis was performed for the initial six patients comparing preoperative to postoperative NHS. Effect size and sample
size were calculated as 2.19 and 5 [actual power (1 − β): 0.93], respectively. Post hoc power analysis showed the actual power of this study was 1.0.

Arthroscopic findings and operative procedures performed
Arthroscopic findings including labral tear, ligamentum teres injury and cartilage damage at the time of surgery are detailed in Table 3. The arthroscopic procedures performed in this study cohort are shown in Table 4. With the respect to labral management, 97% (35 hips) of procedures underwent a labral repair and 3% (1 hip) underwent labral reconstruction using iliotibial band autograft. All patients underwent capsular plication. 78% (28 hips) required cam osteochondroplasty. 3% (1 hip) of procedures required microfracture. 3% (1 hip) removal of loose bodies.
手術時における関節唇断裂、円靭帯損傷及び軟骨損傷等の鏡視下所見は、表3に詳細される。本研究コホートにおいて実施された鏡視下手技は表4に示される。関節唇の治療に関して、手技の97%(35股)が関節唇修復を受け、3%(1股)が自家腸脛靭帯を用いた関節唇再建術を受けた。全患者らは関節包プリケーションを受けた。78%(28股)がCam osteochondroplastyを必要とした。3%(1股)がmicrofractureを必要とし、3%(1股)が遊離体摘出を必要とした。

Radiographic changes
The radiographic changes including the mean LCE angle, Sharp angle and Tonnis angle are detailed in Figs. 4 and 5. The mean LCE angle significantly increased postoperatively from preoperative assessment, but partially decreased at final follow-up. The mean Sharp angle significantly decreased postoperatively from preoperative assessment (p = 0.001), but partially increased at final follow-up (p = 0.001). The mean Tonnis angle significantly decreased postoperatively from preoperative assessment (p = 0.001), but slightly increased at final follow-up (p = 0.016) (Figs. 4, 5).
平均LCEA、Sharp角、及びTonnis angleを含めたレントゲン変化は、図4及び5に詳細される。平均LCEAは、術前評価から術後に有意に増加したが、最終経過観察において一部減少した。平均Sharp角は、術前評価から術後に有意に減少したが、最終経過観察において一部増加した。平均Tonnis angleは、術前評価から術後に有意に減少したが、最終経過観察において若干の増加が認められた(図4,5)。

Patient‑Reported Outcome (PRO) Scores
The mean MHHS significantly improved at 6 months and from 1 to 2 years after surgery (Fig. 6). Similarly, the mean NAHS significantly improved at 6 months, 1 year and 2 years after surgery (Fig. 7). The mean iHOT12 also significantly improved from preoperatively to at final follow-up (p < 0.001) (Fig. 8). Two patients required subsequent surgery in the form of one revision arthroscopy (arthroscopic lysis of adhesions) and one conversion to total hip arthroplasty.

Inter‑ and intra‑observer reliability
Inter- and intra-observer reliability analyses of the radiographic measurements were assessed. The inter-observer/ intra-observer ICCs of the CE angle was 0.738/0.967. The inter-observer/ intra-observer ICCs of Tonnis angle, Sharp angle, and FNS angle were 0.695/0.857, 0.847/0.42 and 0.774/0.932, respectively. The inter-observer/intra-observer reliability of the alpha angle, VCA angle and postope CE angle were 0.738 / 0.506, 0.546/0.966 and 0.556/0.909, respectively. Finally, measurements by a single observer (H.U) were utilized for further analysis.
レントゲン計測の検者間及び検者内信頼性解析が評価された。CE角の検者間/検者内のICCsは0738/0.967であった。Tonnis angle、Sharp角及びFNS angleの検者間/検者内ICCsは、それぞれ、0.695/0.857、0.847/0.42、及び0.774/0.932であった。αアングル、VCAアングル及び術後CEAの検者間/検者内信頼性は、それぞれ、0.738/0.506、0.545/0.966、及び0.556/0.909であった。最後に、単一検者(H.U)による計測が、追加的解析のために利用された。
Return to play sports‑related activity
Patients reported favorable outcomes with the return to sports. 29 of 32 patients were able to return to sports-related activity. Three patients were unable to return to sports activity altogether. Of the latter, one patient experienced progressive knee osteoarthritis and one had multidirectional shoulder instability. One patient opted out of participation in sports by choice and reported no discomfort. The mean period from surgery to return to practice was 9 ± 3.5 months (range 5-18). The mean UCLA-AS score significantly decreased from preinjury to preoperatively and improved from 3.9 preoperatively to 8.7 at the final follow-up (p = 0.001) (Fig. 9a). The UCLA-AS score in 11 of 32 active patients decreased from preinjury to the final follow-up. The UCLA-AS score in 19 of 32 at final follow-up improved to the preinjury level. Two of 32 patients reported UCLA-AS scores above preinjury level (Fig. 9b).

Postoperative complication
A transient lateral femoral cutaneous nerve (LFCN) neuropraxia occurred in two patients. A fracture of the shelf graft was observed in a 15-year-old Judo player. He returned to Judo at 3 months after surgery without physician's permission. He did not require shelf graft refixation because the fracture site was at the midportion of shelf graft with residual coverage.
The most important findings of present study are good clinical outcomes and high rate of return to play and level of athletic function after endscopic shelf acetabuloplasty in active patients. Rotational acetabular osteotomy (RAO) is an option for treating patients with DDH. Several studies demonstrate long-term clinical outcomes following RAO with 77-80% of those patients defined as not progressing to osteoarthritis stage III (Classification of osteoarthrosis of the hip joint adovocated by the Japanese Orthopaedic Association) [18, 23]. While the literature exists for outcomes following RAO in the general population, there is a paucity of studies specified to return to sports activity after RAO in athletes.
Periacetabular osteotomy (PAO) is another popular procedure for treating patients with DDH in the absence of osteoarthritis. There are currently two studies demonstrating clinical outcomes and sports activity following PAO. Van Bergayk et al. reported 19 of 21 patients were able to participate in sports following PAO.
PAOは、OAの無いDDHを有する患者らの治療に対してもう1つの人気の高い手技である。現在、PAO後の臨床的Outcomesとスポーツ活動性を示した2篇の研究が存在する。Van Bergaykらは、21患者中19患者がPAO後にスポーツ参加を可能としたことを報告した。
Recently, Ettinger et al. in other series of 77 patients undergoing PAO have shown the mean UCLA-AS score significantly improved from 4.8 preoperatively to 7.7. However, they did not mention the prevalence of return to play. At final follow-up, the UCLAAS score in our study decreased from preinjury level in 11 active patients (Fig. 9a), returned to preinjury level in 19, and increased beyond preinjury level in 2.
Despite partial resorption of the shelf bone graft observed in this study, the LCE angle representative of lateral coverage remained significantly increased at minimum 2 years of follow-up. Shelf resorption has been known to occur on occasion and has been attributed to high bone graft placement lacking sufficient desirable pressure against the underlying femoral head and interposed capsule [28]. Evidence of graft resorption, even severe, may not necessarily dictate clinical failure.
本研究において観察されたShelf bone graftの部分的吸収にもかかわらず、外側被覆を示すLCEAは、最短2年の経過観察において有意に増加したままであった。場合によって、Shelfの吸収が発生することは知られており、それは、下に存在する大腿骨頭と介在する関節包に対して、十分な望ましい圧迫が不足する、高いBone graftの配置が寄与されるものであった。Graft吸収のエビデンスがたとえ重度であっても、必ずしも、臨床的失敗を示唆しない可能性がある。
This finding was reported in a long-term study of open shelf acetabuloplasty and was attributed to the residual improvement of static lateral coverage [28]. It may be prudent to use an adequately long bone graft to enable sufficient anterolateral coverage (perhaps to a LCE angle near 30°-40° on intra-operative fluoroscopic examination) in anticipation of some partial resorption. Open shelf acetabuloplasty, without intra-articular surgery, has also been performed for the treatment of DDH. Some studies revealed that labral tearing could adversely influence the clinical outcome of shelf acetabuloplasty [1, 10].
この所見は、Open Shelf臼蓋形成術の長期研究において報告されており、静的外側被覆の残存改善が寄与するものであった。一部の骨吸収を考慮して、十分な前外側被覆(おそらく、術中透視検査上30-40度近くのLCEA)を可能にするように十分に長いbone graftを用いることが賢明となる可能性がある。関節内手術を用いないOpen Shelf臼蓋形成術もまた、DDHの治療に対して実施されている。いくつかの研究は、関節唇断裂が、Shelf臼蓋形成術の臨床的Outcomesに負の影響を及ぼす可能性を明らかにした。
Unlike PAO and RAO which can reposition hyaline cartilage into weight-bearing locations via acetabular reorientation, shelf acetabuloplasty relies upon capsular metaplasia into fibrocartilage. Furthermore, the shelf procedure, using a relatively uniplanar bone graft, provides more focal lateral than anterior coverage. Nevertheless, other studies demonstrated that shelf acetabuloplasty without any intra-articular procedures can provide satisfactory long-term results [12, 21].
寛骨臼の再配向を介して荷重領域内にガラス軟骨を再配置できるPAO及びRAOとは異なり、Shelf臼蓋形成術は、関節包の線維軟骨化生に依存する。さらに、相対的に平面的なbone graftを用いたShelf手技は、前方被覆よりも外側の限局性被覆をより多く提供する。それにもかかわらず、他の研究は、いかなる関節内手技を用いないShelf臼蓋形成術が、長期の良好な結果を提供しえることを実証した。
Endoscopic shelf acetabuloplasty is minimally invasive with promising short-term outcomes in a general population with DDH; it is now routinely used for mild or moderate DDH and for cases of failed isolated hip arthroscopy in borderline DDH in our clinical practice. The findings of this study suggest that endoscopic shelf acetabuloplasty may be beneficial for treating active patients with hip dysplasia. However, endoscopic shelf acetabuloplasty is technically demanding and may best be performed by surgeons experienced in hip arthroscopy, somewhat limiting its utility.
Some minor complications such as lateral femoral cutaneous nerve neuropraxia and fracture of shelf graft were found in this study. This procedure required to extend MAP distally to insert shelf graft. In these two cases with lateral femoral cutaneous nerve palsy, a Tinel-like sign was produced upon tapping the MAP incision. To avoid LFCN palsy, we prefer the modified MAP which is slightly lateral to the classic MAP. Fracture of shelf graft could occur both intraoperatively and postoperatively.
外側大腿皮神経障害やShelf graftの骨折のようないくつかのMinor合併症が本研究において認められた。本手技は、Shelfグラフトを挿入するために、MAPの遠位の延長を必要とした。外側大腿皮神経麻痺を有したこれら2例において、Tinel様サインがMAP切開上をタップしたときに生じた。LFCN麻痺を避けるために、我々は、通常のMAPに対して若干外側となるmodified MAPを好んで使用する。Shelf graftの骨折は、術中と術後の両方に発生しえる可能性がある。
Patient compliance with postoperative rehabilitation including avoidance of premature return to sport may lessen this complication, as well as adhesive capsulitis. This study has several limitations. This was a retrospective short-term case series without a control group. Isolated hip arthroscopic labral repair might be considered as a control group, but recent studies suggest that moderate dysplasia patients cannot benefit from isolated hip arthroscopic procedures without a PAO or shelf procedure, preventing clinical equipoise. A mid- to long-term prospective randomized study is desirable to collect more information regarding shelf graft remodeling and durability of outcomes.
早期スポーツ復帰の回避を含めた術後リハビリテーションの患者遵守は、この合併症だけでなく、癒着性関節包炎を軽減する可能性がある。本研究はいくつかの制限を有する。本研究は、対照群を有さない、後ろ向き短期症例シリーズであった。単独鏡視下関節唇修復術が、対照群として考慮される可能性があったが、最近の研究は、中等度形成不全患者が、臨床的均衡を防止するためのPAOまたはShelfを有さない単独股関節鏡手技から利点を得ることが出来ないことを示唆する。中期から長期の前向き無作為化研究が、Shelf graftのリモデリング及びOutcomesの耐久性に関するさらなる情報を収集するために望まれる。
VCA angle was measured, however, given the variance of pelvic positioning on false profile views, and it is difficult to measure the VCA angle precisely. Some studies have shown that the VCA angle is not reliable to determine accurate anterior coverage of the acetabulum. Another limitation is the lack of a strict definition of an athlete, one of our study inclusion criteria. We did not limit the study to stratify patients into professional and/or elite athlete groupings but chose to investigate all patients with self-reported competitive athletic endeavors of various aforementioned types.
VCA angleが、false profile view上の骨盤配置の多様性を考慮して、計測されたが、正確にVCA angleを計測することは難しい。いくつかの研究は、VCA angleが寛骨臼の正確な前方被覆を判定するために確実なものではないことを示してきた。別の制限は、我々の研究包含基準の1つである、アスリートの厳格な定義が不足したことが挙げられる。我々は、患者らをプロフェッショナル及び/またはエリートアスリート群に細分化するために、研究に制限を設けず、多様な前述のタイプの自己申告の競技スポーツを有した全ての患者を調査することを選択した。
Although the UCLAAS was captured as a measure of sports-related activity, a limitation is the absence of data on frequency and duration of resumed athletic endeavor. The clinical significance of this study is evidence-based support for the addition of a minimally invasive option to open acetabular reorientation osteotomy for not only sedentary but athletic patients with symptomatic mild to moderate dysplasia. In practice, dysplasia with LCEA between approximately 15°-20°, perhaps too severe for predictably good outcomes from hip arthroscopy alone, may still be candidates for endoscopic shelf acetabuloplasty adding bony support along with the benefits of concurrent hip arthroscopy to treat coexistent intra-capsular pathology.
UCLA-ASがスポーツ関連活動性の計測として用いられたが、スポーツ再開の努力期間と頻度に関する情報が無く、制限となる。本研究の臨床的重要性は、症候性の軽度から中等度の形成不全を有する非アスリートだけでなくスポーツ患者に対するOpen 寛骨臼矯正骨切り術に対する追加的低侵襲選択肢に対するエビデンスベースの支持を提供することにある。臨床において、股関節鏡単独から予測可能な良好なOutcomeにとって、おそらく、重度すぎる可能性のある約15-20度のLCEAを伴う形成不全は、依然として、共存する関節包内病変を治療するための同時股関節鏡の利点を伴った骨性支持を追加する鏡視下Shelf臼蓋形成術に対する候補者である可能性がある。
Endoscopic shelf acetabuloplasty provides promising clinical outcomes and return to sports-related activity for active patients with DDH.