Arthroscopic Fragment Fixation Using Hydroxyapatite/Poly-L-Lactate Acid Thread Pins for Treating Elbow Osteochondritis Dissecans

Arthroscopic Fragment FixationUsing Hydroxyapatite/Poly-L-Lactate AcidThread Pins for Treating ElbowOsteochondritis Dissecans

Soshi Uchida,*y MD, PhD, Hajime Utsunomiya,y MD, PhD,Tomonori Taketa,y MD, PhD, Shinsuke Sakoda,y MD, PhD, Akihisa Hatakeyama,z MD,Toshitaka Nakamura,z MD, PhD, and Akinori Sakai,z MD, PhDInvestigation performed at the Wakamatsu Hospital for the University ofOccupational and Environmental Health, Kitakyushu, Japan

Background: Various procedures, such as arthroscopic debridement, osteochondral transplantation, and bone plug fixation, havebeen described for the treatment of osteochondritis dissecans (OCD) of the humeral capitellum. However, the use of hydroxyapatite/poly-L-lactate acid (HA/PLLA) thread pins to fix the osteochondral fragment in an OCD lesion is a recent development.

Hypothesis: Adolescent throwing athletes would return to preinjury levels of function after arthroscopic osteochondral fragmentfixation using HA/PLLA thread pins.

Study Design: Case series; Level of evidence, 4.

Methods: Enrolled in this prospective cohort study were 18 adolescent baseball players (mean age, 14.2 years; range 12-16, years) withelbow OCD who underwent arthroscopic fragment fixation with HA/PLLA thread pins between 2006 and 2009. All patients were affectedon their dominant side. Plain radiographs taken before surgery showed an open physis in 13 patients (72%) and a closed physis in 5patients (28%). During surgery, the condition of the OCD lesion was evaluated by use of the International Cartilage Research Society(ICRS) classification system; there were 5 grade II, 11 grade III, and 2 grade IV cases. Outcomes were assessed after 3 years (mean,39 months; range, 36-50 months). Elbow function was measured using the Timmerman and Andrews score and the Mayo Elbow Per-formance Index. Return to sports activity was assessed as higher than preinjury, same level, lower level, or no return to sports.

Results: The mean Timmerman and Andrews score improved significantly from 126.6 6 6.5 to 197.5 6 1.5, and the mean MayoElbow Performance Index improved significantly from 68.0 6 2.1 to 98.06 6 0.9 (P = .0001 for both). Mean elbow extensionimproved significantly from 210� 6 10.4� to 20.8� 6 5.2� (P = .006), and mean flexion improved significantly from 123.1� 6

17.9� to 138.6� 6 6.1� (P = .001). Three patients had a loss of extension greater than 5�. Five patients returned to a higher levelof sports activity, 10 patients returned to the same level, and 2 patients returned to a lower level. A remaining patient did not returnto baseball. In one patient, the lesion did not heal, resulting in fragmentation at 1 year after surgery. This patient consequentlyunderwent revision arthroscopy to remove the lesion, and he eventually returned to sports at the same level of activity.

Conclusion: Arthroscopic fragment fixation using HA/PLLA thread pins provides a beneficial clinical outcome to adolescentbaseball players with humeral capitellar OCD.

Keywords: osteochondritis dissecans (OCD); elbow arthroscopy; arthroscopic fragment fixation

Osteochondritis dissecans (OCD) of the humeral capitel-lum is characterized by the separation of osteochondrallesions from the subchondral bone. Repetitive valgus forceapplied to the humeral capitellum during the throwingaction creates the unstable lesions of OCD. A recent histo-logical study19 suggested that repetitive microtraumacould cause osteochondral separation. Takahara et al33

classified OCD lesions as either stable or unstable and pro-vided guidelines for treatment options in the adolescentbaseball player using their OCD classification system.They have also proposed that some stable lesions

*Address correspondence to Soshi Uchida, MD, PhD, Department ofOrthopaedic Surgery, Wakamatsu Hospital for the University of Occupa-tional and Environmental Health, 1-17-1 Hamamachi, Wakamatsu, Kita-kyushu, Japan (email: [email protected]).

yDepartment of Orthopaedic Surgery, Wakamatsu Hospital for theUniversity of Occupational and Environmental Health, Kitakyushu, Japan.

zDepartment of Orthopaedic Surgery, Faculty of Medicine, Universityof Occupational and Environmental Health, Kitakyushu, Japan.

One or more of the authors has declared the following potential conflict ofinterest or source of funding: S.U. has been a consultant for BioMed andSmith & Nephew and a member of the advisory board of Depuy Mitek.

The American Journal of Sports Medicine, Vol. XX, No. XDOI: 10.1177/0363546515570871� 2015 The Author(s)

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AJSM PreView, published on March 3, 2015 as doi:10.1177/0363546515570871

(International Cartilage Repair Society [ICRS] grade II)with an open physis could be treated nonoperatively,34

although stable ICRS grade II lesions with a closed physisand unstable ICRS grade III and IV lesions would nor-mally require surgical treatment.17,32

Arthroscopic surgery, including removal of loose bodiesand debridement, is a valuable procedure for diagnosingand treating elbow osteochondral lesions.6 However, poorclinical outcomes after debridement have been reported inlesions that extend through the lateral margin of the capi-tellum. When treatment involves fragment removal alone,the result is absence of a complete circumferential borderof healthy articular cartilage and subchondral bone.4,28 Infact, Takahara et al32 reported that clinical outcomesdepend on the size of the humeral capitellum defect. Theyrecommended bone peg fixation and/or fragment fixationto treat stable central lesions (such as ICRS grade II,when the lesion size is .50% of the surface area).

Several reports using techniques such as pull-out wiring,Herbert screw fixation, or bone plugs to fix an OCD lesionfragment have shown good clinical outcomes and high ratesof union.11,20,27 Takahara et al32 reported that fragment fix-ation procedures reduce pain, compared with fragmentremoval procedures. However, fragment fixation proceduresnormally require an open surgical approach, which riskscausing postoperative range of motion defects and pain.

Arthroscopic approaches using bioabsorbable osteo-synthetic implants, such as poly-L-lactide acid (PLLA)implants, have recently been reported useful in attachingOCD fragments. Takeba et al35 reported arthroscopic frag-ment fixation of OCD lesions of the humeral capitellum usingbioabsorbable pins made of PLLA (Gunze Bone FixationDevice; Stryker). However, several practical problems withPLLA implants have been reported. The mechanical strengthof fixation is sometimes not sufficient, because there is nobonding capability with the surrounding bone.10,12 Addition-ally, both intraoperative management and postoperativeassessment can be difficult because radiolucent PLLA mate-rial cannot be seen on radiographs, and thus an image inten-sifier is required during and after surgery.

Alternatively, hydroxyapatite (HA)/PLLA compositematerials are widely used in bone defects as a strong fillermaterial, having the long-term benefit of being osteoconduc-tive.25,30 Composite materials made of HA/PLLA can be eas-ily managed intraoperatively because they can be seen ona plain radiograph. Once HA/PLLA pins are properlyplaced, their initial mechanical strength is much greaterthan that of PLLA alone.22,31 Importantly, HA/PLLA pinsare believed to enable better osteochondral fragment reinte-gration over time.25 In vitro studies have revealed that oste-oblastic cells cultured on HA/PLLA membranes have bettercell adhesion and proliferation ability than do osteoblasticcells cultured on PLLA alone.22,31 Moreover, in vivo stud-ies10,12 demonstrated that HA/PLLA rods implanted in rab-bit femurs will persist for up to 2 years but will begin todetectably resorb by 3 years and will shrink further by 4years. As the rods are resorbed, the area undergoes properbone remodeling. The rods are gradually replaced withproperly interconnected trabecular bone, which shouldlead to a better clinical outcome.10,12

In this study, we used HA/PLLA thread pins in a newarthroscopic technique for fragment fixation in OCD of theelbow and investigated the clinical outcomes after 3 years.The purpose of this study was to determine the success ofthe clinical outcome after arthroscopic osteochondral frag-ment fixation using HA/PLLA pins in the treatment ofOCD of the humeral capitellum in throwing athletes.

MATERIALS AND METHODS

From 2006 to 2009, a total of 18 consecutive male patientswith humeral capitellar OCD underwent an arthroscopicosteochondral fragment fixation procedure at our institute.All patients had been engaged competitively in the throw-ing sport of baseball but were unable to perform their sportactivities at the time of surgery because of severe elbowpain. The mean age of the patients at the time of surgerywas 14.28 6 0.3 years.

We applied several inclusion and exclusion criteria toour patient population. Inclusion criteria for this surgerywere defined as the failure of nonoperative treatmentsfor more than 3 months and positive symptoms for anOCD lesion at the elbow joint obtained by radiographyand magnetic resonance imaging (MRI). Exclusion criteriawere defined as ligament instability, osteoarthritis, or Lit-tle League elbow. Examples of nonoperative treatmentsincluded resting the affected elbow, using nonsteroidalanti-inflammatory drugs, and reconditioning of the shoul-der and elbow function, such as periscapular conditioning.To evaluate medial instability of the elbow joint, the valgusstress test was manually performed with the patient’selbow in 30� of flexion. The test was considered positivewhen laxity of the elbow was 2 mm greater than that ofthe contralateral elbow and/or in the presence of a signifi-cantly soft end point feeling. None of the study patientshad signs of medial instability of the elbow.5,7

Patient Demographics

All 18 patients were affected on their dominant side. Nopatients had any previous surgery on the affected elbow.Plain radiographs showed an open physis in 13 patients(72%) and a closed physis in 5 (28%) (see Appendix 1, avail-able online at http://ajsm.sagepub.com/supplemental).Twelve lesions were located in the extensive lateral portionof the capitellum (Figure 1A), and 8 were located in thecenter of the capitellum (Figure 1B) (Appendix 1). Accord-ing to the MRI classification system described by De Smetet al,8 there were 7 patients with grade II, 9 with grade III,and 2 with grade IV lesions.

Surgical Technique for ArthroscopicFragment Fixation of OCD Lesions

Before surgery, we evaluated the location of the OCDlesions by 3-dimensional computed tomography (3D-CT)(Figure 2, A and B). We began the arthroscopic procedure

2 Uchida et al The American Journal of Sports Medicine

by assessing the patient and the lesion. The patient wasfirst placed in a supine position under general anesthesia.We performed a physical examination before the surgery,visually assessing the osteochondral fragment for size,location, and stability. We used a standard 4.0-mm arthro-scope (Dyonics; Smith & Nephew) with a 30� angled lensand arms for fluid inflow and suction outflow to view theanterior compartment of the elbow joint via an anterolat-eral and a proximal medial portal (Figure 2C). This wasfollowed by direct visualization of the OCD lesion througha soft-spot portal and a modified distal ulnar portal. Themodified distal ulnar portal was placed approximately2 cm distal to the posterior aspect of the radiocapitellarjoint and 5 mm lateral to the palpable posterior edge ofthe ulnar. This is a modification of the distal ulnar portaldescribed by van den Ende et al38 (Figure 2D).

We classified our arthroscopic findings of the OCDlesion according to the ICRS classification system, in whichgrade I lesions are stable but softened and covered byintact cartilage, grade II lesions have a partial discontinu-ity that is softened but not displaced when probed, gradeIII lesions have a complete discontinuity but are not dis-placed, and grade IV lesions are empty defects or defectswith a dislocated fragment or a loose fragment.3

After visual assessment but before the actual arthro-scopic fixation procedure, we prepared the fixation site. Ifthe OCD lesion observed was a grade II or III lesion, weused an awl to perform a microfracture, and we refreshedthe subchondral bone and the surrounding tissue until itbled. If the lesion observed was a grade IV lesion and thehyaline cartilage was undamaged, we abraded the base ofthe lesion to obtain viable subchondral bone until it bled.

Before the procedure, we determined the length of theHA/PLLA thread pins (Super Fixorb 30-thread pin;Takiron Co Ltd) by measuring the size and the depth ofthe osteochondral lesion of the capitellum on CT. We beganthe arthroscopic procedure by fixing the osteochondralfragment using the HA/PLLA thread pins (Figure 3A),using Depuy Super Fixorb instrument to fix the pins

(Figure 3B). With the target elbow flexed and with gooddistention established, we inserted a guide tube 2 or 3mm in diameter through the soft-spot portal or the modi-fied distal ulnar portal (Figure 4).38 If we needed to fixan OCD lateral lesion, we inserted a guide tube throughthe soft-spot portal while viewing from a scope located inthe modified distal ulnar portal; if we needed to fix anOCD central lesion, we inserted a guide tube through themodified distal ulnar portal while viewing from a scopelocated in the soft-spot portal. We made a guide hole tothe appropriate depth using a custom-made dilator bit(Figure 4B) and drilled through the drill guide to thedesired depth by using a Kirschner wire. Generally, wefound that drilling a hole a few millimeters deeper thanthe length of the HA/PLLA pin was desirable to minimizeintraosseous pressure. During the drilling procedure, wesometimes used intermittent drilling to minimize tempera-ture increases, which avoided causing thermal necrosis.The dilator was inserted into the drill guide and was tap-ped to the desired depth. Next, we inserted the HA/PLLApins through the drill guide, with a delivery tamp to fixthe displaced or detached osteochondral lesion (Figure 2,E and F; and Figure 4). We usually used at least 2 or 3HA/PLLA pins to prevent rotation after surgery, especiallyif the lesion was unstable (ICRS grade III or IV). Last, weconfirmed a secure fixation by probing the OCD lesion(Figure 2F) (see the Video Supplement).

Four-Phase Postoperative Rehabilitation Protocol

The postoperative rehabilitation procedure is detailed inAppendix 2, available online. During phase I (postopera-tive weeks 1-4), reducing inflammation and protectingthe fixed OCD lesion were the cornerstones of the rehabil-itation process. We immobilized the elbow for 2 weeks at90� of flexion with a removable splint in the neutral posi-tion of the wrist and the hand, to protect the fixed OCDlesion. Gentle passive range of motion (ROM) exercises

Figure 1. Osteochondritis dissecans classification. Anteroposterior plain radiographs in flexion at 45� of elbow flexion showingfragmentation and radiolucency lesions of the humeral capitellum (white arrows): (A) extensive lateral type, (B) central type, and(C) isolated lateral type.

Vol. XX, No. X, XXXX Arthroscopic Fixation for Elbow OCD 3

were initiated during the first week under the supervisionof a physical therapist, to avoid elbow joint stiffness. Con-tinuous passive motion (CPM) was used to avoid adhesivecapsulitis, by applying 0� to 90� of elbow flexion for up to 1hour a day for 2 weeks. Patients were allowed to undergoisometric muscle exercising of triceps, biceps, and othermuscles surrounding the shoulder joint; periscapular andshoulder isometric strengthening could also be instituted,as could manual therapy, including soft tissue scar massageand gentle joint immobilization. Cardiovascular training was

initiated after removal of stitches 2 weeks after surgery.Cryotherapy and electrical stimulation, as needed, were

Figure 3. Hydroxyapatite/poly-L-lactate (HA/PLLA) pin andcustom-made drill bit system. (A) Two HA/PLLA pins (diame-ter: 2 mm [top] and 3 mm [bottom]). The pins, a forged com-posite of 30% HA and 70% PLLA, are bioactive andbioresorbable. They are threaded and headless, applied byuse of compression force. (B) Custom-made drill bit system:removal tamp, a; dilator, b; delivery tamp, c; drill guide, d.

Figure 2. A 16-year-old baseball player came to our cliniccomplaining of right elbow pain for the previous 6 months.He underwent nonoperative treatments including physicaltherapy and a nonsteroidal anti-inflammatory agent, buttreatment was not effective. (A) An anteroposterior radio-graph of the elbow in 45� of flexion showing flattened andradiolucency lesion of the capitellum. (B) Three-dimensionalcomputed tomographic imaging showing an extensive lateral-type osteochondritis dissecans (OCD) lesion in the capitellum.Arthroscopic view of the lesion via the (C) proximal anterome-dial portal and (D) and (E) the modified distal ulnar portal withdrill guide inserted from lateral soft-spot portal of the elbow jointin flexion. (F) Five hydroxyapatite/poly-L-lactate acid (HA/PLLA)pins were fixed at the OCD lesion. HC, humeral capitellum; RH,radial head.

Figure 4. Arthroscopic fragment fixation of hydroxyapatite/poly-L-lactate (HA/PLLA) pins. (A) The patient a supine position.(B) Scope viewing from the modified distal ulnar portal and drillguide insertion from the lateral soft-spot portal with the elbowjoint in flexion. The HA/PLLA pins were then delivered underarthroscopic visualization by use of a delivery tamp.

4 Uchida et al The American Journal of Sports Medicine

performed and continued to phase III. The milestones for pro-gression to phase II were no pain, no swelling, and obtaining80% of the ROM of the uninvolved side.

During phase II (weeks 4-12), the patients progressed inmobility and muscle strength. Active ROM exercise wasadvanced to full ROM. Patients were allowed to start isotonicnonweightbearing elbow muscle exercise at 6 weeks aftersurgery. Upper bicycle ergometer exercise with low resis-tance was initiated. Milestones for progression to phase IIIwere involved shoulder and elbow strength that was at least80% that of the noninvolved side, satisfactory proprioception,and no pain during weightbearing in the involved extremity.

During phase III (weeks 12-16), cryotherapy, periscapularand shoulder strengthening, and core strengthening werecontinued. Patients were allowed partial weightbearing exer-cise of the elbow once union of the OCD lesion was confirmedby radiograph, MRI, and 3D-CT. Milestones for progressionto phase IV were involved shoulder and elbow strength ofat least 80% of the noninvolved side, satisfactory propriocep-tion, no pain with weightbearing through the involvedextremity, and complete healing of the OCD lesion.

During phase IV (week 16 onward), plyometric exerciseswere initiated. We also allowed patients to start an inter-val throwing program.1

Postoperative Assessment

We evaluated all patients for ROM at the elbow joint. Elbowfunction was assessed using the Timmerman and Andrews37

clinical rating system and the Mayo Elbow PerformanceIndex.26 We used the Timmerman and Andrews37 scoring sys-tem, consisting of both subjective (pain, swelling, locking, and/or catching) and objective (ROM) evaluations, to decide whenpatients could return to their normal activity levels. Clinicalscores were classified into the following 4 categories: excellent(180-200), good (160-179), fair (120-159), or poor (\120). Weallowed patients to return to preinjury activity levels whentheir Timmerman and Andrews score reached good or excellent.

Postoperative radiographs with an anteroposteriorelbow view, lateral view, and radiocapitellar congruitywith 45� of flexion view (tangential view) were obtainedevery month until 6 months after surgery, and CT scanswere obtained at 4 months, 6 months, and 1 year after sur-gery. In all patients, we performed CT in a standardizedfashion. Patients underwent helical multislice CT scan-ning (64-slice Aquilion CX) with 2-mm helical thicknesspitch including the radius, ulnar, and humerus (slice, 0.53 64 mm; 120 kV; 240 mA; field of view[FOV], 200 mm;speed, 1.5 s; helical pitch, 41; slice thickness of each axial,coronal, and sagittal slice, 2.0 mm). Reconstructed imagesof the elbow were used to reproduce a standardized 2-dimensional image representing the healing process afterfragment fixation by use of the HA/PLLA pins.

Fixation of the Super Fixorb HA/PLLA pins was assessedat 12 months after surgery with a 3.0-T MRI unit (SignaEXCITE HD; GE Health Care) for 17 of 18 patients. Theremaining patient did not have an MRI examinationbecause he underwent subsequent revision arthroscopy.High-resolution proton-density turbo spin echo (PD-TSE),

T2*-weighted images, and short inversion-recovery (STIR)sequence images were obtained in coronal, sagittal, andaxial sections as follows:

1. PD-TSE sequence: coronal (repetition time [TR]/echo time[TE]: 3000/20 ms; FOV, 160 mm; matrix, 352 3 256; slicethickness, 4 mm) and axial (TR/TE, 3000/20 ms; FOV, 160mm; matrix, 384 3 256; slice thickness, 4 mm).

2. T2*-weighted sequence: coronal (TR/TE, 550 ms/1 min;FOV, 160 mm; matrix, 352 3 256; slice thickness, 4mm), sagittal (TR/TE, 500 ms/1 min; FOV, 160 mm;matrix, 352 3 256, slice thickness, 4 mm), and axial(TR/TE, 500 ms/1 min; FOV, 160 mm; matrix, 352 3

256; slice thickness, 4 mm).3. STIR sequence: coronal (TR/TE, 4600/65 ms; FOV, 140

mm; matrix, 288 3 244; slice thickness, 4 mm) and axial(TR/TE, 4600/65 ms; FOV 140 mm; matrix, 352 3 256;slice thickness, 4 mm).

The magnetic resonance observation of cartilage repairtissue (MOCART) scoring system was used to evaluate themorphological condition of the repaired cartilage tissueand the surrounding cartilage.21,23,40 MOCART scoring isa point-scoring system designed to systematically recordthe constitution of the osteochondral fragment fixationarea and surrounding tissues. It has been shown to be reli-able and reproducible when applied to various surgical car-tilage repair procedures.21,23,40 The maximum score, basedon the evaluation of 9 parameters, is 100. These parametersare degree of repair defect filling (M1), cartilage interface(M2), cartilage surface (M3), structure of repaired tissue(M4), signal intensity (M5), constitution of the subchondrallamina (M6), constitution of the subchondral bone (M7),adhesion (M8), and intra-articular effusion (M9).

Return to Sports Activities

We assessed return to preinjury sports activity and dividedthe outcome into 4 categories: higher than preinjury, samelevel, lower level, or unable to return to sports. Evaluationswere made by use of a modified version of the return to pre-injury sports activity level assessment established by theAmerican Shoulder and Elbow Surgeons.16

Statistical Analysis

All data are presented as the mean and the standard errorof the mean. Preoperative scores were compared with 3-year follow-up scores using the Mann-Whitney U test. Sta-tistical analyses were performed using the SPSS softwarepackage (v 13; IBM Corp). The level of significance wasset at P \ .05.

RESULTS

Arthroscopic Findings

We detected an osteochondral fragment, with arthroscopi-cally intact surrounding cartilage, in all 18 patients.

Vol. XX, No. X, XXXX Arthroscopic Fixation for Elbow OCD 5

According to ICRS classification,3 there were 5 grade IIlesions, 11 grade III lesions, and 2 grade IV lesions. Themean number of HA/PLLA pins per lesion was 3.1 6 1.1(range, 1-5) (Appendix 1).

Clinical Evaluation of Elbow Function

We observed significant improvements in elbow functionin our patient population at follow-up compared withpreoperative assessments. At a mean follow-up intervalof 39 months (range, 36-50 months), the mean Timmer-man and Andrews score improved significantly from126.6 6 6.5 to 197.5 6 1.5 (P = .0001). The mean MayoElbow Performance Index improved from 68.0 6 2.1 to98.06 6 0.9 (P = .0001). The mean range of elbow exten-sion improved significantly from 210� 6 10.4� to 20.8� 6

5.2� (P = .006), and the mean range of elbow flexionincreased from 123.1� 6 17.9� to 138.6� 6 6.1� (P =.001). Three patients had a loss of extension of greaterthan 5� at the time of final follow-up. The mean prona-tion and supination did not significantly change fromthe preoperative measurement (supination, 83� 6 3�and pronation, 88� 6 11�) to the 3-year follow-up

(supination, 88� 6 4� and pronation, 89� 6 8�) (P = .06for supination and P = .88 for pronation).

The overall 3-year evaluation of recovery was excellentin 17 patients but fair in 1 patient. The patient with a fairoutcome still had a limited range of motion at follow-up.His radiograph showed progressive osteoarthritic changes.In the 17 patients evaluated as having an excellent elbowfunction recovery, 1 had occasional persistent mild pain.In patient 2, shown in online Appendices 1 and 3, thelesion did not heal well, resulting in fragmentation at 1year after surgery. Consequently, this patient underwentrevision arthroscopy, and the lesion was removed. He even-tually had an excellent recovery and returned to same levelof activity.

Return to Sports Activities

At the 3-year follow-up, 5 of the 18 patients returned toa higher level of activity, 10 patients returned to samelevel, and 2 patients returned to a lower level. The remain-ing patient did not return to baseball but instead playedsoccer. He eventually ceased all sports activity due to a psy-chogenic disorder (Appendix 3).

Figure 5. (A) Preoperative tangential view demonstrating a flattening and radiolucent osteochondritis dissecans (OCD) lesion withan open capitellar physis. (B) Tangential view showing postoperative improvement of radiolucency at the humeral capitellum, justafter surgery. (C) Plain radiograph tangential view showing complete union at 6 months after surgery. (D) Three-dimensional com-puted tomography (CT) scan showing complete union at 12 months after surgery. (E) CT sagittal plane view showing the OCDlesion before surgery. (F) CT sagittal view showing complete union of the lesion at 4 months after surgery. (G) T2-weighted sagittalview and (H) proton-density sagittal view showing complete healing of the lesion at 12 months after surgery. There was no evi-dence of bone marrow edema and adhesive tissue surrounding the lesion.

6 Uchida et al The American Journal of Sports Medicine

Radiographic Evaluation

Plain radiographs made at the time of follow-up revealedbone healing in all patients (Figure 5). The mean time ofbone union based on CT was 18.8 6 3 weeks (Appendix3). Only 1 of 2 patients with ICRS grade IV (patient 2)had a loose body after returning to preinjury activity,which was not completely healed in the central portion.He underwent second-look arthroscopy to remove the loosebody (Appendix 1). The other remaining ICRS grade IVcase (patient 3) had a completely healed lesion, but hedid not return to preinjury activity level due to a psycho-genic disorder (Appendix 3).

The overall evaluation of the postoperative MRI at 1 yearafter surgery revealed a mean MOCART score of 87 (range,30-100; see Appendix 3). More than 80% of patients hadgood healing of the fragment as detected by parametersM1 to M4 of the MOCART scoring system. About 72% to76% of patients had normal signal intensity. Overall,patients showed no evidence of joint inflammation, suchas adhesive capsulitis (M8) or joint effusion (M9). Specifi-cally, regarding parameter M1 (filling of the defect) therewas complete fill in 9 patients (53%) and hypertrophy fillin 7 patients (41%) but more than 50% incomplete fill in 1patient (6%). For M2 (cartilage interface), there was com-plete interface in 10 patients (59%), demarcation in 6patients (35%), and partial defect in 1 patient (6%). M3 (car-tilage surface) results were intact in 15 patients (88%) andwere damaged less than 50% depth in 2 patients (12%).M4 (OCD lesion structure) showed homogeneous results in13 patients (76%) and nonhomogeneous in 4 patients(24%). The M5 (signal intensity) result on T2* signalshowed normal results in 12 patients (71%) and nearly nor-mal in 5 (29%); signal intensity PD-TSE was normal in 14patients (82%) and abnormal in 3 patients (18%). For M6(subchondral lamina), results were intact in 16 patients(94%) and not intact in 1 patient (6%). M7 (subchondralbone) showed intact results in 13 patients (76%) and notintact in 4 patients (24%). No evidence of adhesion wasseen in 15 patients (88%), and 2 patients were adhesion pos-itive (12%). Joint effusion was not observed in 14 patients(82%) but was seen in 4 patients (24%) (Appendix 4).

DISCUSSION

Our 3-year clinical outcome study revealed that arthro-scopic fragment fixation using HA/PLLA pins is an effectivetreatment for humeral capitellar OCD in adolescent ath-letes. We have established, with our clinical assessment,that it is possible to achieve excellent results with this pro-cedure, as occurred in 17 of the 18 patients we treated. Ourclinical outcomes from using this procedure are similar tothose of open surgical procedures. The rate of return to pre-injury activity, after an open surgical procedure, rangesfrom 68% to 100%.9,20,27,36 This rate is similar to what weobserved in our patients (94%) at 3-year follow-up.

Arthroscopic fragment fixation with HA/PLLA pins isindicated only for certain types of elbow OCD lesions:lesions that are more than 50% of the humeral capitellum

(especially in extensive lateral type lesions), stable lesionswith a closed physis, and unstable lesions. Other indica-tions, defined in terms of the chondral damage ICRS clas-sification system, include some stable ICRS grade IIlesions with a closed physis and unstable ICRS grade IIIlesions. Further, arthroscopic fragment fixation with HA/PLLA pins should be indicated for lesions that do notimprove after appropriate nonoperative treatment.

Arthroscopy to treat elbow OCD has several advan-tages. The procedure is minimally invasive, and it hasthe potential for early rehabilitation. An elbow lesion, aswell as the entire elbow joint itself, is readily accessible.Concurrent lesions can be readily identified and treated.Loose bodies can be readily removed. Arthroscopic debride-ment of the fragment for treating unstable OCD has beenreported by several authors.4,18,29 These reports describeoverall improvements in pain and ROM, despite a variablereturn to preinjury activity.

However, arthroscopy still has some disadvantages,which are related to the type of lesion treated. Poor resultsafter arthroscopic debridement have been noted in lesionsthat extend through the lateral margin of the capitellum,resulting in the absence of a complete circumferential bor-der of healthy articular cartilage and subchondralbone.2,4,29 Clinical outcomes of arthroscopic debridementappear to depend on lesion size. Cartilage defects greaterthan 50% of the capitellar width are predisposed to osteo-arthritis, irrespective of whether they are central OCDlesions.32 Thus, when one is attempting to maintain jointstability in patients with a large extensive lesion or unsta-ble lesions, fragment fixation or osteochondral autografttransplantation should still be considered. Positive resultsfrom open reduction and fragment fixation for treatingunstable or separated lesions have been reported by sev-eral authors,11,20,27,32,34 using techniques such as pull-outwiring, Herbert screw fixation, and bone plugs. In level 4studies, Kuwahata and Inoue20 revealed 8 patients whounderwent Herbert screw fixation and bone grafting thatresulted in a 100% bone union rate and a 100% return tosports. Harada et al9 demonstrated that dynamic staplefragment fixation and bone grafting resulted in a 100%bone union rate, with 75% of 4 patients returning to sports.

We used HA/PLLA thread pins, but severalauthors13,14,24,39 have reported successful clinical resultsafter osteochondral autologous transplantation (OAT) forcapitellar OCD lesions. This alternative strategy has beenshown to be a reasonable option for the treatment of OCD.It requires resurfacing the OCD lesion with hyaline that issupported by normal subchondral bone. However, a consider-able disadvantage of performing mosaicplasty is the poten-tially adverse effect on donor sites, especially in skeletallyimmature patients. Concern exists as to whether harvestingosteochondral grafts from the patellofemoral joint has conse-quences on growth plates.15 In contrast, the benefit of ourprocedure is that it is less invasive, there is no requirementto harvest grafts, and there is no risk of donor site morbidity.

However, our study does have limitations. First, we couldnot include a control group, such as patients with nonopera-tive treatment or open screw fixation. Thus, we could notevaluate the true effectiveness of this surgery compared

Vol. XX, No. X, XXXX Arthroscopic Fixation for Elbow OCD 7

with nonoperative treatment or compared with another sur-gical procedure, including arthroscopic debridement and/orOAT. Second, this study only had a small number of cases.A larger number of cases, as well as a longer term follow-up, is needed in future research on this procedure.

CONCLUSION

This less-invasive arthroscopic procedure using HA/PLLAthread pins resulted in excellent 3-year clinical outcomesin adolescent baseball players with humeral capitellarOCD.

ACKNOWLEDGMENT

The authors thank Dr Antonio G. Candeliere for help withmanuscript preparation and Mr Yuji Yano for his contin-ued help with collecting patient data.

A Video Supplement for this article is available in the online

version or at http://ajsm.sagepub.com/supplemental.

REFERENCES

1. Axe MJ, Snyder-Mackler L, Konin JG, Strube MJ. Development of

a distance-based interval throwing program for Little League-aged

athletes. Am J Sports Med. 1996;24(5):594-602.

2. Baker CL III, Romeo AA, Baker CL Jr. Osteochondritis dissecans of

the capitellum. Am J Sports Med. 2010;38(9):1917-1928.

3. Britterberg M, Winalski CS. Evaluation of cartilage injuries and repair.

J Bone Joint Surg Am. 2003;85(suppl 2):58-59.

4. Brownlow HC, O’Connor-Read LM, Perko M. Arthroscopic treatment

of osteochondritis dissecans of the capitellum. Knee Surg Sports

Traumatol Arthrosc. 2006;14(2):198-202.

5. Bruce JR, Andrews JR. Ulnar collateral ligament injuries in the throw-

ing athlete. J Am Acad Orthop Surg. 2014;22(5):315-325.

6. Byrd JW, Elrod BF, Jones KS. Elbow arthroscopy for neglected

osteochondritis dissecans of the capitellum. J South Orthop Assoc.

2001;10(1):12-16.

7. Cain EL Jr, Andrews JR, Dugas JR, et al. Outcome of ulnar collateral

ligament reconstruction of the elbow in 1281 athletes: results in 743

athletes with minimum 2-year follow-up. Am J Sports Med.

2010;38(12):2426-2434.

8. De Smet L, Fabry G. Grip strength in patients with tennis elbow: influ-

ence of elbow position. Acta Orthop Belg. 1996;62(1):26-29.

9. Harada M, Ogino T, Takahara M, Ishigaki D, Kashiwa H, Kanauchi Y.

Fragment fixation with a bone graft and dynamic staples for osteo-

chondritis dissecans of the humeral capitellum. J Shoulder Elbow

Surg. 2002;11(4):368-372.

10. Hasegawa S, Ishii S, Tamura J, et al. A 5-7 year in vivo study of high-

strength hydroxyapatite/poly(L-lactide) composite rods for the inter-

nal fixation of bone fractures. Biomaterials. 2006;27(8):1327-1332.

11. Inoue G. Bilateral osteochondritis dissecans of the elbow treated by

Herbert screw fixation. Br J Sports Med. 1991;25(3):142-144.

12. Ishii S, Tamura J, Furukawa T, et al. Long-term study of high-strength

hydroxyapatite/poly(L-lactide) composite rods for the internal fixation

of bone fractures: a 2-4-year follow-up study in rabbits. J Biomed

Mater Res B Appl Biomater. 2003;66(2):539-547.

13. Iwasaki N, Kato H, Ishikawa J, Masuko T, Funakoshi T, Minami A.

Autologous osteochondral mosaicplasty for osteochondritis dissecans

of the elbow in teenage athletes. J Bone Joint Surg Am.

2009;91(10):2359-2366.

14. Iwasaki N, Kato H, Ishikawa J, Saitoh S, Minami A. Autologous

osteochondral mosaicplasty for capitellar osteochondritis dissecans

in teenaged patients. Am J Sports Med. 2006;34:1233-1239.

15. Iwasaki N, Kato H, Kamishima T, Suenaga N, Minami A. Donor site eval-

uation after autologous osteochondral mosaicplasty for cartilaginous

lesions of the elbow joint. Am J Sports Med. 2007;35(12):2096-2100.

16. King G, Richards R, Zuckerman J, et al. A standardized method for

assessment of elbow function. Research Committee, American Shoul-

der and Elbow Surgeons. J Shoulder Elbow Surg. 1999;8:351-354.

17. Kobayashi K, Burton KJ, Rodner C, Smith B, Caputo AE. Lateral

compression injuries in the pediatric elbow: Panner’s disease and

osteochondritis dissecans of the capitellum. J Am Acad Orthop

Surg. 2004;12(4):246-254.

18. Krijnen MR, Lim L, Willems WJ. Arthroscopic treatment of osteo-

chondritis dissecans of the capitellum: report of 5 female athletes.

Arthroscopy. 2003;19(2):210-214.

19. Kusumi T, Ishibashi Y, Tsuda E, et al. Osteochondritis dissecans of

the elbow: histopathological assessment of the articular cartilage

and subchondral bone with emphasis on their damage and repair.

Pathol Int. 2006;56(10):604-612.

20. Kuwahata Y, Inoue G. Osteochondritis dissecans of the elbow man-

aged by Herbert screw fixation. Orthopedics. 1998;21(4):449-451.

21. Lee KT, Choi YS, Lee YK, Cha SD, Koo HM. Comparison of MRI and

arthroscopy in modified MOCART scoring system after autologous

chondrocyte implantation for osteochondral lesion of the talus.

Orthopedics. 2011;34(8):e356-e362.

22. Li LH, Kommareddy KP, Pilz C, Zhou CR, Fratzl P, Manjubala I. In

vitro bioactivity of bioresorbable porous polymeric scaffolds incorpo-

rating hydroxyapatite microspheres. Acta Biomater. 2010;6(7):2525-

2531.

23. Marlovits S, Singer P, Zeller P, Mandl I, Haller J, Trattnig S. Magnetic

resonance observation of cartilage repair tissue (MOCART) for the

evaluation of autologous chondrocyte transplantation: determination

of interobserver variability and correlation to clinical outcome after 2

years. Eur J Radiol. 2006;57(1):16-23.

24. Miyamoto W, Yamamoto S, Kii R, Uchio Y. Oblique osteochondral

plugs transplantation technique for osteochondritis dissecans of

the elbow joint. Knee Surg Sports Traumatol Arthrosc. 2009;17(2):

204-208.

25. Moroni A, Faldini C, Marchetti S, Manca M, Consoli V, Giannini S.

Improvement of the bone-pin interface strength in osteoporotic bone

with use of hydroxyapatite-coated tapered external-fixation pins:

a prospective, randomized clinical study of wrist fractures. J Bone

Joint Surg Am. 2001;83(5):717-721.

26. Morrey B, An K-N, Chao E. Functional Evaluation of the Elbow. Phil-

adelphia, PA: Saunders; 1993.

27. Nobuta S, Ogawa K, Sato K, Nakagawa T, Hatori M, Itoi E. Clinical

outcome of fragment fixation for osteochondritis dissecans of the

elbow. Ups J Med Sci. 2008;113(2):201-208.

28. Rahusen FT, Brinkman JM, Eygendaal D. Results of arthroscopic

debridement for osteochondritis dissecans of the elbow. Br J Sports

Med. 2006;40(12):966-969.

29. Ruch DS, Cory JW, Poehling GG. The arthroscopic management of

osteochondritis dissecans of the adolescent elbow. Arthroscopy.

1998;14(8):797-803.

30. Shikinami Y, Okuno M. Bioresorbable devices made of forged com-

posites of hydroxyapatite (HA) particles and poly L-lactide (PLLA),

part II: practical properties of miniscrews and miniplates. Biomateri-

als. 2001;22(23):3197-3211.

31. Sui G, Yang X, Mei F, et al. Poly-L-lactic acid/hydroxyapatite hybrid

membrane for bone tissue regeneration. J Biomed Mater Res A.

2007;82(2):445-454.

32. Takahara M, Mura N, Sasaki J, Harada M, Ogino T. Classification,

treatment, and outcome of osteochondritis dissecans of the humeral

capitellum. J Bone Joint Surg Am. 2007;89(6):1205-1214.

33. Takahara M, Mura N, Sasaki J, Harada M, Ogino T. Classification,

treatment, and outcome of osteochondritis dissecans of the humeral

8 Uchida et al The American Journal of Sports Medicine

capitellum: surgical technique. J Bone Joint Surg Am. 2008;90(suppl

2 pt 1):47-62.

34. Takahara M, Ogino T, Fukushima S, Tsuchida H, Kaneda K. Nonop-

erative treatment of osteochondritis dissecans of the humeral capi-

tellum. Am J Sports Med. 1999;27(6):728-732.

35. Takeba J, Takahashi T, Hino K, Watanabe S, Imai H, Yamamoto H.

Arthroscopic technique for fragment fixation using absorbable pins

for osteochondritis dissecans of the humeral capitellum: a report of

4 cases. Knee Surg Sports Traumatol Arthrosc. 2010;18(6):831-835.

36. Takeda H, Watarai K, Matsushita T, Saito T, Terashima Y. A surgical

treatment for unstable osteochondritis dissecans lesions of the

humeral capitellum in adolescent baseball players. Am J Sports

Med. 2002;30(5):713-717.

37. Timmerman LA, Andrews JR. Arthroscopic treatment of posttraumatic

elbow pain and stiffness. Am J Sports Med. 1994;22(2):230-235.

38. van den Ende KI, McIntosh AL, Adams JE, Steinmann SP. Osteo-

chondritis dissecans of the capitellum: a review of the literature

and a distal ulnar portal. Arthroscopy. 2011;27(1):122-128.

39. Vogt S, Siebenlist S, Hensler D, et al. Osteochondral transplantation

in the elbow leads to good clinical and radiologic long-term results:

an 8- to 14-year follow-up examination. Am J Sports Med.

2011;39(12):2619-2625.

40. Zak L, Krusche-Mandl I, Aldrian S, Trattnig S, Marlovits S. Clinical

and MRI evaluation of medium- to long-term results after autologous

osteochondral transplantation (OCT) in the knee joint. Knee Surg

Sports Traumatol Arthrosc. 2014;22(6):1288-1297.

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