Arthroscopic Bioabsorbable Screw Fixation of Unstable Osteochondritis Dissecans in Adolescents: Clinical Results, Magnetic Resonance Imaging, and Second-Look Arthroscopic Findings

Investigation of the appropriate thread depth for bioabsorbable screws

The relatively low strength of bioabsorbable screws is a critical clinical issue. A shallower thread depth will increase a screw's strength, but the pull-out strength of the screw will decrease proportionally with the thread depth. We sought to provide further clarification of the relationships between (i) the thread depth and the pull-out strength, and (ii) the minor diameter and the shearing and bending strengths in bioabsorbable screws made of uncalcined and unsintered hydroxyapatite particles and poly-L-lactide (u-HA/PLLA). Seven types (thread depth from 0.1-0.7 mm) of screws with a major diameter of 4.5 mm were manufactured. Each screw type's pull-out strength was investigated using simulated bone. A shearing test and three-point bending test were both used to measure the physical strength of the screws. We then analyzed the relationships between the mechanical findings and the thread depth. The relationship between the thread depth and the pull-out strength showed a positive biphasic linear correlation with a boundary at 0.4-mm thread depth. The relationships between the minor diameter and both the shearing and bending strengths showed positive linear correlations within the range of dimensions tested. Within the scope of this study, a 0.4-mm thread depth proved to be an appropriate value that provides sufficient pull-out strength and screw strength for u-HA/PLLA screws with a 4.5-mm major diameter.

Preoperative and Postoperative Imaging and Outcome Scores for Osteochondral Lesion Repair of the Ankle

Cartilage lesions to the ankle joint are common and can result in pain and functional limitations. Surgical treatment aims to restore the damaged cartilage's integrity and quality. However, the current evidence for establishing best practices in ankle cartilage repair is characterized by limited quality and a low level of evidence. One of the contributing factors is the lack of standardized preoperative and postoperative assessment methods to evaluate treatment effectiveness and visualize repaired cartilage. This review article seeks to examine the importance of preoperative imaging, classification systems, patient-reported outcome measures, and radiological evaluation techniques for cartilage repair surgeries.

Bioabsorbable Screw Fixation Provides Good Results With Low Failure Rates at Mid-term Follow-up of Stable Osteochondritis Dissecans Lesions That Do Not Improve With Initial Conservative Treatment

Purpose

To evaluate the clinical and radiographic outcomes of patients who have undergone bioabsorbable screw fixation for intact, stable grade I and II osteochondritis dissecans (OCD) lesions for which at least 6 months of conservative management has failed.

Methods

A retrospective review of prospectively collected data from a single institution was performed to identify patients who underwent internal fixation of stable grade I and II OCD lesions (according to the Guhl classification) between January 2010 and January 2020. Patients were included regardless of the presence of concomitant procedures. The inclusion criteria consisted of (1) primary surgery, (2) failure of at least 6 months of conservative management, (3) the use of a bioabsorbable screw (or screws), and (4) minimum 2-year clinical follow-up. Radiographs were obtained at a minimum of 1 year postoperatively. Patient demographic characteristics, clinical patient-reported outcomes, complications, and failure rates were noted.

Results

Twenty-four knees among 23 patients (96% follow-up) were analyzed and followed up for 6.36 ± 3.42 years (range, 2.0-12.7 years). Patients showed statistically significant postoperative improvements in all patient-reported outcomes including the Lysholm score, International Knee Documentation Committee score, and Knee Injury and Osteoarthritis Outcome Score subscales (P < .05). In 3 knees (12%), a reoperation was required due to failure at an average of 3.64 years after the index procedure. No specific complications were attributed to the use of bioabsorbable screws. Patients in whom primary surgical treatment failed did not differ in demographic characteristics, arthroscopic findings, or surgical treatment from those who had successful treatment.

Conclusions

Internal fixation of stable grade I and II OCD lesions with bioabsorbable screws produces reliable results with a 12% rate of failure in appropriately indicated patients in whom at least 6 months of conservative management has failed. Clinical outcomes improved significantly during the mid-term follow-up period.

Level of Evidence

Level IV, therapeutic case series.

Association of Stability and Size of Unhealed Area With Failure After Internal Fixation for Osteochondritis Dissecans Lesions of the Knee: Radiological Evaluation Using Computed Tomography

BACKGROUND

Open reduction and internal fixation (ORIF) has been widely performed because the osteochondral component of the osteochondritis dissecans (OCD) lesion is the most suitable for reconstructing the joint structure.

PURPOSE

To evaluate radiological healing in terms of reconstructed bony structure after ORIF with bone graft by computed tomography (CT), to identify preoperative prognostic factors for failure, and to determine the cutoff value of radiological healing for risk of failure.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A retrospective cohort study of 42 patients (44 knees) who underwent internal fixation with bone graft for OCD lesions of the knee from 2004 to 2018 was conducted. All patients were evaluated 6 months postoperatively, and if not healed 6 months after surgery, they were evaluated by CT periodically thereafter. Radiological healing was judged according to the following 3 criteria: (1) reossification of the OCD lesion, (2) bony continuity between the OCD lesion and basal floor, and (3) reconstructed bony surface of the femoral condyle reconstructed to match the normal joint. Then, the percentage of the radiological healing area was calculated as the ratio of the healing length to the total lesion length. The nonhealing area was calculated by multiplying the sum of the total nonhealing length. Clinical failure was defined as any definitive reoperation for the same OCD lesion, such as fragment excision, or a cartilage restoration procedure. After 6 months, all eligible patients underwent arthroscopy to check for protrusion of the absorbable pin into the joint; the removal of an absorbable pin protruding into the joint was not considered a failure.

RESULTS

Clinical failure was recorded for 4 cases (9.1%). The mean overall percentage of the radiological healing area of OCD 6 months after ORIF with bone graft was 79.5% ± 24.4%, and the mean overall nonhealing area at 6 months was 87.8 ± 107.9 mm2. The percentages of radiological healing area of stable (International Cartilage Regeneration & Joint Preservation Society OCD II) lesions and femoral condylar (lateral femoral condyle + medial femoral condyle) lesions were significantly lower than unstable lesions and femoral groove lesions, respectively (P = .01 and P = .03, respectively). On receiver operating characteristic curve analysis, the cutoff points for predicting a significantly increased risk of failure were 33.9% (sensitivity, 100%; specificity, 100%; area under the curve, 1) for the percentage of radiological healing area and 222.9 mm2 (sensitivity, 95%; specificity, 100%; area under the curve, 0.956) for the nonhealing area 6 months postoperatively.

CONCLUSION

A stable lesion and a femoral condylar lesion were the predictors of poor radiological healing on CT images 6 months after ORIF with bone graft. The risk of failure was increased significantly in cases with only approximately one-third of the lesion healed or in cases with large nonhealing areas at 6 months postoperatively.

Suture-Bridge Fixation of Osteochondral Fractures and Osteochondritis Dissecans in the Knee: Excellent Rates of Early Lesion Stability and Osseous Union

BACKGROUND

Preservation of articular cartilage in the setting of acute or chronic injury in the adolescent and young adult knee is paramount for long-term joint health. Achieving osseous union, minimizing implant-related injury, and eliminating the need for reoperation for traumatic chondral and osteochondral lesions (OCLs) and osteochondritis dissecans (OCD) remain a challenge for the orthopaedic surgeon.

PURPOSE

To evaluate radiographic healing, patient-reported outcomes, and short-term complications after suture-bridge fixation of chondral fragments, osteochondral fractures, and OCD lesions in the knee.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The study included consecutive patients (38 patients, 40 knees) treated within a single academic sports medicine institution who underwent suture-bridge fixation of an OCL or an OCD lesion of the knee from initiation of the technique in October 2019 through March 2021. The suture-bridge technique entailed bioabsorbable knotless anchors placed on the outside margins of the lesion with multiple strands of hand-tensioned absorbable (No. 0 or No. 1 Vicryl) or nonabsorbable (1.3-mm braided polyester tape) bridging suture. Healing was assessed by radiography and magnetic resonance imaging (MRI), with MRI scans obtained on all OCD lesions and any chondral-only lesions. MRI scans were available for 33 of 40 (82.5%) knees within 1 year of surgery and were evaluated for lesion healing. Complications and rates and timing of return to sport were evaluated. Patient-reported outcomes in the OCD cohort were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS) to determine early pain and functional improvement.

RESULTS

In total, 33 (82.5%) lesions demonstrated full union, and no lesions failed treatment. MRI assessment of healing (mean, 5.8 months; range, 3-12 months) demonstrated 9 (64.3%) OCD lesions with full union, 5 (35.7%) OCD lesions with stable union, and no OCD lesions with nonunion. Of the OCLs, 17 (89.5%) had full union, 2 (10.5%) had stable union, and none had nonunion. The 7 bony OCLs without an MRI scan demonstrated complete radiographic union. In 30 (75.0%) lesions, patients returned to sports at a mean of 6.5 months (range, 3.8-10.2 months). KOOS Activities of Daily Living, Pain, Quality of Life, and Symptoms scores demonstrated significant improvement from baseline at 6 months and at 1 year. There were 2 (5%) complications, consisting of reoperation for marginal chondroplasty on an otherwise stable lesion, and re-operation for intial un-treated patellar instability, with no reoperations for failure or revision of the suture-bridge construct.

CONCLUSION

In this series of OCLs and OCD lesions of the knee, suture-bridge fixation demonstrated excellent rates of MRI and radiographic union and good early outcomes with minimal short-term complications. This technique may be used for lesion salvage as an alternative to metallic and nonmetallic screw/tack constructs in the treatment of these challenging lesions. Longer term follow-up and investigation are warranted.

Failure of osteochondral lesions using bioabsorbable fixation in the adolescent patient: a case report

Injury to the chondral surface and subchondral bone can be due to osteochondritis dissecans or traumatic injury. These lesions can lead to pain, swelling, and mechanical symptoms causing functional impairments for patients. Treatment can include nonoperative management or surgical intervention including internal fixation. Internal fixation can be performed through multiple methods including the use of bioabsorbable screw fixation, though there is concern for potential early failure of this method. We present three cases of osteochondral lesions treated with internal fixation with bioabsorbable screws, which experienced early failure of the bioabsorbable screws, leading to failure of fixation and requiring revision surgery with advanced cartilage restoration procedures. All patients had resolution of their symptoms and improved function postoperatively. While the use of bioabsorbable screw fixation can potentially decrease cost and morbidity, their mechanical properties may increase the risk of failure before lesion healing. We advocate caution with the use of these screws for the treatment of unstable osteochondritis dissecans lesion and recommend careful patient selection and meticulous surgical technique to avoid failure of fixation of these lesions.

Reattachment of Osteochondritis Dissecans Lesions in the Lateral Femoral Trochlear Ridge With Bioabsorbable Screws in 4 Yearling Standardbreds

This case series describes an alternative surgical technique to obtain reattachment of osteochondritis dissecans (OCD) lesions in the lateral trochlear ridge of the femur (LTRF) as well as the clinical and radiological outcome of treated cases. Four Standardbred yearlings (6 lesions in total) underwent surgical fixation of large OCD defects in the LTRF under arthroscopic guidance. Reattachment of the OCD lesions was obtained using 3.0/3.7 mm headless bio-compression and absorbable poly-l-lactic acid (PLLA) screws, inserted perpendicularly to the cartilage surface through the lesion. All horses were discharged from the hospital without complications. Clinical and radiological follow-up were collected and reviewed at 6 and 12 months post-operatively. Successful healing of the OCD lesions occurred in all cases based on radiographic evaluations, associated with a reduction of femoro-patellar effusion. All horses presented in this case series were able to enter regular training program as racehorses.

Evaluation of Osteochondritis Dissecans Treatment with Bioabsorbable Implants in Children and Adolescents

(1) Background: This is the first systematic review concerning the treatment of osteochondritis dissecans with the use of bioabsorbable implants. The study was done as a comprehensive review to identify important factors affecting the results of OCD treatment in children and adolescents; (2) Methods: We searched electronic bibliographic databases including PubMed, Cochrane Library, Scopus, and Web of Knowledge until May 2022. This systematic review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and PICO (Patients, Interventions, Comparisons, Outcomes) guidelines; (3) Results: We identified 2662 original papers of which 11 were found to be eligible for further analysis. The study group included a total of 164 OCD lesions in 158 patients. In 94.86% of postoperative cases, there was complete healing or local improvement on follow-up CT or MRI scans. The great majority of patients achieved a good clinical effect. Out of 164 OCD lesions, 10 did not heal (6.09%); (4) Conclusions: Surgical treatment of stable and unstable OCD in children with the use of bioabsorbable implants facilitates a high rate of healing and a good clinical outcome; treatment of juvenile OCD is associated with a better outcome compared to adult OCD; the use of bioabsorbable implants for the treatment of humeral capitellum OCD is associated with a more frequent incidence of synovitis (18.2%).

Outcomes of bioabsorbable fixation in the treatment of osteochondral lesions of the knee in adolescent patients

BACKGROUND

Bioabsorbable fixation in managing osteochondral lesions is increasing in popularity. The purpose was to report on outcomes using bioabsorbable fixation nails for osteochondral lesions of the knee in a pediatric and adolescent population.

METHODS

A retrospective review of pediatric patients undergoing surgery with bioabsorbable fixation for knee osteochondral lesions was performed. Demographic, clinical, and surgical data was collected including symptom duration, lesion location, size, use of bone grafting, and number of implants. Return to activities was documented. Patients recommended revision surgery were compared to those who were not.

RESULTS

47 patients with median age 13.9 years and 25.5% female were included with median clinical follow-up of 47.3 weeks. 87.2% of patients were cleared for full activities. Four male patients (8.5%) were recommended revision surgery, of whom three underwent surgery including removal of loose bioabsorbable fixation. Demographic data did not differ between the group with successful versus failed primary surgery (p > 0.05). Symptom duration was more acute (<1 month) in the four recommended revision surgery (75% versus 9.3%, p = 0.008). The group recommended revision also had larger lesion size (median 5.4 cm² versus 2 cm², p = 0.04). Distal femoral physeal status, lesion location, necessity for bone grafting, and number of implants did not differ between groups.

CONCLUSIONS

Adolescents had a high return to activity following bioabsorbable fixation for knee osteochondral lesions with 87.2% cleared for full return. In the 8.5% of patients who were deemed to have failed primary fixation, symptoms were more likely to be acute in nature with larger lesion sizes.

Surgical treatment of atraumatic osteochondrosis dissecans of the immature talus-Clinical results and prevalence of radiographic joint degeneration after a median follow-up of 72.5 months

BACKGROUND

This study aimed to assess the clinical and radiographic outcomes of different surgical procedures in atraumatic osteochondrosis dissecans (OCD) of the talus in youth and adolescence.

METHODS

32 joints in 30 patients (mean age 14.7 ± 2.2 years) were evaluated. Numeric Rating Scale (NRS), Foot and Functional Index (FFI), American Orthopedic Foot and Ankle Society ankle-hindfoot score (AOFAS), Pediatric Outcome Data Collection Instrument (PODCI), and sport participation were recorded. We compared preoperative and follow-up ankle radiographs to identify specific features in the OCD morphology and any signs of joint degeneration.

RESULTS

After a median follow-up period of 72.5 months the drilling group showed significantly better scores than the combined fixation and reconstruction groups (AOFAS, p = 0.024; PODCI, p = 0.003; NRS, p = 0.027). Signs of joint degeneration were observed in 50% of all ankles, especially in those treated by OCD-fixation and reconstruction.

CONCLUSIONS

Advanced fixation and reconstruction procedures in unstable and non-salvageable atraumatic talar OCD resulted in inferior clinical scores and a higher prevalence of joint degeneration than drilling procedures in stable OCD in young patients.

Second-look arthroscopic and magnetic resonance analysis after internal fixation of osteochondral lesions of the talus

The purpose of this study was to evaluate cartilage quality after internal fixation of osteochondral lesion of the talus (OLT) using second-look arthroscopies and MRIs. Thirty-four patients underwent internal fixation of OLTs involving large bone fragments. Twenty-one of these patients underwent second-look arthroscopies and 23 patients underwent MRIs postoperatively. The arthroscopic findings were assessed using the International Cartilage Repair Society (ICRS) grading system, and the MRI findings were evaluated using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Five of the patients who underwent second-look arthroscopies showed normal cartilage, 12 showed nearly normal cartilage, 3 showed abnormal cartilage, and 1 showed severely abnormal cartilage, according to the overall ICRS repair grades. All the patients who achieved bone fragment union showed normal, or nearly normal cartilage upon second-look arthroscopy. The ICRS and MOCART scores were significantly higher for the patients with bone fragment union compared to those with nonunion (ICRS scores: 10.3 ± 1.5 vs. 6.0 ± 2.0, p < 0.001, MOCART score: 88.3 ± 10.0 vs. 39.0 ± 20.4, p < 0.001). Low signal intensities of the bone fragments on preoperative T1-weighted MRIs were not associated with nonunion (Fisher's exact test, p = 0.55), and the signal intensities increased postoperatively to levels similar to the underlying talus when bone union was achieved. Second-look arthroscopy and MRI showed normal, or nearly normal, cartilage after internal fixation of OLTs when bone union was achieved. The nonunion of bone fragments resulted in inferior cartilage quality.

Biomechanical Analysis of Unstable Osteochondral Fragment Fixation Using Three Different Techniques: Osteochondral Plug, Bioabsorbable Pin, and Suture Anchor with Tape

Purpose

To compare the initial fixation strength of osteochondral fragment fixations using osteochondral plugs, bioabsorbable pins, and knotless suture anchors.

Methods

Eighteen fresh-frozen immature (6 month old) porcine knees were used. An osteochondral fragment, cut from the articular surface of the medial femoral condyle to achieve a thickness of 5 mm, was used to mimic the unstable osteochondral fragment. It was fixed using three techniques, including two osteochondral plugs (osteochondral plug group), four full-threaded poly l-lactic acid pins (bioabsorbable pin group), and three suture anchors with a 2-0 tape (suture anchor group). Tensile loads at displacements of 1 and 2 mm and ultimate failure load were measured at a cross-head speed of 100 mm/min, and the variables of the three groups were compared statistically using a one-way ANOVA with Tukey’s honestly significant difference test.

Results

There was no significant difference in the tensile load to achieve 1-mm displacement. The load to achieve 2-mm displacement and the ultimate failure load were significantly greater in the suture anchor group than the osteochondral plug group and the bioabsorbable pin group.

Conclusions

Single-pull destructive testing of a fixed articular osteochondral fragment with the force perpendicular to the articular surface, demonstrated no statistical difference in the tensile load to achieve 1-mm displacement, but the load to achieve 2-mm displacement was significantly greater for the three suture anchor-interlocking 2-0 tape constructs than the dual osteochondral plug fixation and the four bioabsorbable pin fixation constructs. Additionally, the three suture anchor-interlocking 2-0 tape construct’s mean single-pull failure load was greater than other two fixation procedures.

Clinical Relevance

To achieve osteochondral fragment union, sufficient fixation strength is critical. However, the initial fixation strength of osteochondral plugs, bioabsorbable pins, and knotless suture anchors for unstable osteochondral lesions remains unclear.

Internal Fixation of Lateral Trochlear Groove Osteochondritis Dissecans With Simultaneous Lateral Retinacular Lengthening in Adolescent Athletes

BACKGROUND

The goals of operative treatment for the adolescent athlete with unstable osteochondritis dissecans (OCD) lesion are rigid fixation and prevention of recurrence.

PURPOSE

To evaluate clinical and radiological outcomes of internal fixation of lateral trochlear groove OCD with simultaneous lateral retinacular lengthening.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Adolescent athletes who had undergone internal fixation and simultaneous lateral retinacular lengthening for an unstable OCD lesion of the lateral trochlear groove were retrospectively reviewed. Subjective assessments included the Lysholm score, International Knee Documentation Committee (IKDC) subjective score, Tegner activity scale, and an athletic questionnaire. Functional tests included isokinetic muscle strength, single-leg hop for distance, single-leg vertical jump, and Y-balance. Pre- and postoperative radiographs and magnetic resonance images were reviewed.

RESULTS

The mean ± SD age of the 17 patients included in this study was 15.9 ± 0.9 years; last clinical follow-up duration was 37.7 ± 8.1 months. At the last follow-up, the Lysholm score improved from 68.7 ± 15.3 to 93.4 ± 12.4 and the IKDC subjective score from 60.2 ± 14.7 to 88.7 ± 12.7 (P < .001). The mean Tegner activity scale score was 9.4 ± 0.5 before injury and 8.9 ± 1.2 at the last follow-up (P = .059). The limb symmetry indices of isokinetic muscle strength, single-leg hop for distance, single-leg vertical jump, and Y-balance improved at the last follow-up; the mean limb symmetry index was ≥85% in each functional test. Regarding the athletic questionnaire, 16 (94.1%) patients were satisfied with the surgery. At the last follow-up, 2 patients had higher ability after returning to sports, 11 had the same ability, and 3 had lower ability than the preinjury level. Postoperative magnetic resonance imaging at 12-month follow-up showed that the OCD lesion appeared healed in 7 (41.2%) patients and partially healed in 9 (52.9%).

CONCLUSION

Internal fixation of lateral trochlear groove OCD with simultaneous lateral retinacular lengthening in adolescent athletes achieved satisfactory clinical and radiological outcomes. Therefore, this combined surgical technique could be considered an effective treatment for lateral trochlear groove OCD, with a high rate of return to sport.

Does the Symmetry of Patellar Morphology Matter When Matching Osteochondral Allografts for Osteochondral Defects Involving the Central Ridge of the Patella?

OBJECTIVE

The purpose of this study was to determine if differences in Wiberg classification play a role in the ability of donor patellar osteochondral allografts to match the native patellar surface when treating osteochondral defects of the patellar apex.

DESIGN

Twenty (10 Wiberg I and 10 Wiberg II/III) human patellae were designated as the recipient. Each recipient was size-matched to both a Wiberg I and a Wiberg II/III patellar donor. A 16-mm circular osteochondral "defect" was created on the central ridge of the recipient patella. The randomly ordered donor Wiberg I or Wiberg II/III plug was harvested from a homologous location and transplanted into the recipient. The recipient was then nano-CT (computed tomography) scanned, digitally reconstructed, registered to the initial nano-CT scan of the recipient patella, and processed to determine root mean squared circumferential step-off heights as well as surface height deviation. The process was then repeated for the other allograft plug.

RESULTS

There was no significant difference in mean step-off height between matched and unmatched Wiberg plugs; however, there was a statistically significant difference in surface height deviation over the whole surface (0.50 mm and 0.64 mm respectively, P = 0.03). This difference of 0.14 mm is not felt to be clinically significant. Tibial width was correlated to patellar width (r = 0.82) and patellar height (r = 0.68).

CONCLUSIONS

For osteochondral allograft sizes up to 16 mm there appears to be no advantage to match donor and recipient patellar morphology. Further study is warranted to evaluate defects requiring larger graft sizes.

Knotless Suture Anchor Fixation of a Traumatic Osteochondral Lesion of the Lateral Femoral Condyle

Osteochondral injuries commonly occur after lateral patellar instability events. Recognition and early intervention of displaced fragments is key to maintaining the viability of the fragment and congruency of the articular surface. Multiple fixation techniques exist for achieving stable fixation of displaced osteochondral lesions, including metal or bioabsorbable screws and all suture techniques. In this Technical Note, we describe a technique for internal fixation of a displaced osteochondral fragment of the lateral femoral condyle using knotless suture anchors. This technique affords minimally invasive restoration of the native anatomy with excellent stability of the fracture fragment, allowing early range of motion and ambulation.

Internal Fixation of Osteochondral Lesion of the Talus Involving a Large Bone Fragment

BACKGROUND

Internal fixation of an osteochondral lesion of the talus (OLT) can restore the congruency of the talus and maintain the subchondral bone and innate hyaline cartilage. However, OLT that is indicated for fixation is rarely encountered; hence, not many studies report on the results after the procedure.

PURPOSE

To evaluate the clinical and radiological outcomes after internal fixation of chronic OLT involving a large bone fragment of at least 10 mm in diameter and 3 mm in depth on computed tomography (CT).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We retrospectively reviewed the data of 26 patients with OLT treated with internal fixation between August 2014 and April 2018. Of the patients, 15 were male and 11 were female, with a mean age of 16 years (range, 11-29 years). The primary radiological outcome measurement was bone union assessed on the 6-month postoperative CT scan. Clinical outcomes were assessed at a mean of 27.7 months postoperatively.

RESULTS

Twenty patients (77%) achieved bone union on postoperative CT scan. The mean 100-mm visual analog scale (VAS) improved from 30.5 ± 8.5 preoperatively to 13.4 ± 9.7 postoperatively (P < .001). The mean Foot Function Index (FFI) improved from 30.5 ± 6.7 preoperatively to 13.7 ± 9.8 postoperatively (P < .001). A malleolar osteotomy was not necessary to approach the lesion in 88% of patients. A bone fragment with an irregular margin and low density on the preoperative CT scan was significantly associated with nonunion (odds ratio: 7.67, 95% confidence interval: 2.67 to 22.02, P = .008). The difference in clinical outcomes between patients with skeletally immature ankles and those with skeletally mature ankles was not statistically significant. Patient age did not correlate with postoperative 100-mm VAS (Pearson correlation coefficient, r = -0.07, P = 0.72) or the postoperative FFI (Pearson correlation coefficient, r = -0.05, P = .80).

CONCLUSION

Internal fixation of an OLT involving a large bone fragment resulted in satisfactory clinical and radiologic outcomes. We found that patients with skeletally immature and mature ankles attained healing at comparable rates after the internal fixation of OLT.

Bioabsorbable Unsintered Hydroxyapatite/Poly-l-Lactic Acid Pin Fixation of Osteochondritis Dissecans in Adolescents: Initial Experiences

BACKGROUND

This study sought to retrospectively evaluate the clinical and magnetic resonance imaging (MRI) outcomes of u-HA/PLLA pin (u-HA/PLLA: hydroxyapatite/poly-L-lactic acid) pin fixation of unstable osteochondritis dissecans (OCD) lesions of the knee.

METHODS

Seven adolescent patients (four females and three males) with arthroscopically unstable OCD lesions of the knee were included. The mean age at diagnosis was 13.1 years. Clinical results were evaluated preoperatively and during follow-up using the Ogilvie-Harris score (0 - 15 points). MRI scans were performed preoperatively and during follow-up, with results evaluated using the Dipaola classification (grades 1 - 4). Mean follow-up time was 29 months.

RESULTS

The median Ogilvie-Harris score improved from 13 points (range: 10 - 14 points) to 15 points (range: 13 - 15 points). Separately, the median Dipaola score improved from 3 points (range: 2 - 4 points) to 1 point (range: 1 - 4 points). No complications such as infection, synovitis, or intra-articular adhesion were observed.

CONCLUSIONS

Initial experiences using bioabsorbable u-HA/PLLA pins for the refixation of unstable OCD lesions in adolescents in the knee are promising, and MRI provides excellent monitoring of healing.

Management of the Failed OCD

PURPOSE OF THE REVIEW

Osteochondritis dissecans (OCD) is a pathologic condition of subchondral bone most frequently occurring in the medial femoral condyle of the knee in children and adolescents. Salvage techniques are necessary when either nonoperative or typical operative treatments fail, or the OCD presents in an unsalvageable state. The purpose of this review is to describe the evaluation and management of failed OCDs.

RECENT FINDINGS

Thorough preoperative planning is essential to the treatment of failed OCDs. Radiographs and advanced imaging such as MRI and CT allow for a detailed assessment of subchondral bone and cartilage. Long-leg alignment radiographs are critical to assess for malalignment which may increase the contact forces on the affected condyle. Malalignment can be corrected with hemiepiphysiodesis or an osteotomy depending on the skeletal maturity of the patient. Osteochondral allografts and autologous chondrocyte implantation treat the defect in both bone and cartilage or solely cartilage and have good short to moderate term outcomes, particularly as compared to the inferior outcomes of microfracture of larger OCDs. Osteochondritis dissecans of the knee that fails to heal with initial operative measures can result in a large defect of bone and cartilage in the knee of adolescents. Treatment of the bone and cartilage defect can be accomplished with either osteochondral allograft transplantation or matrix-assisted autologous chondrocyte implantation can be performed with good outcomes. Assessment and correction of lower extremity malalignment is a critical component of treatment. Durable long-term solutions are necessary for the treatment of these difficult lesions.

Magnetic resonance evaluation of the pediatric knee after arthroscopic fixation of osteochondral lesions with biodegradable nails

PURPOSE

To use magnetic resonance imaging (MRI) to investigate the knee joint of children following arthroscopic fixation of osteochondral lesions using bioabsorbable nails and to correlate these imaging findings with time from arthroscopic treatment and with risk factors at the time of imaging.

MATERIALS AND METHODS

Our study included postarthroscopic MRI studies from 58 children (mean age at arthroscopy, 13.8 + 2.1 years) who have undergone bioabsorbable nail fixation of unstable osteochondral lesions between February 1, 2011 and September 30, 2017. All studies were retrospectively reviewed for broken nails, intra-articular debris, and internal knee derangement. Demographic information and information pertaining to active symptoms was obtained from both MRI questionnaire that was completed at the time of the study and clinical note that preceded the study. Marginal logistic regression models estimated using generalized estimating equations (GEE) were used to identify factors associated with a broken nail and joint effusion.

RESULTS

A total of 104 postoperative studies were reviewed, which included 60 with symptoms and 44 without symptoms. Nail breakage was present in 38 (36.6%) studies and associated with presence of symptoms (OR 2.43, p = 0.036) and effusion (OR 2.76, p = 0.025). An effusion was present in 40 (38.5%) studies which decreased with increasing time from treatment (OR 0.89, p = 0.007) and increased with symptoms (OR 10.87, p < 0.001). Meniscal tear was present on 8 (7.7%) and chondral irregularity on 14 (13.5%) studies.

CONCLUSION

Broken nail, effusion, and less commonly, meniscal tears and chondral irregularity, are all complications that can arise following fixation of osteochondral lesions with bioabsorbable nails. MRI can serve as a valuable tool in assessing these complications.

Open Reduction Internal Fixation of a Traumatic Osteochondral Lesion of the Patella With Bioabsorbable Screw Fixation

Osteochondral injuries of the patella occur often in the setting of traumatic patellar dislocations. Early fixation of the displaced fragment(s) is paramount to maintaining the viability of the articular cartilage and the congruency of the patella. Multiple fixation techniques have been described to ensure stable fixation, including wires, screws, and all-suture techniques with both absorbable and nonabsorbable materials. We performed an open reduction and internal fixation of a large traumatic patellar osteochondral lesion using 3 bioabsorbable compression screws. The technique is straightforward and provides compression across the fragments, affording excellent stability, which allows early range of motion and ambulation.

A Case Series of Successful Repair of Articular Cartilage Fragments in the Knee

BACKGROUND

It is unclear whether chondral fragments without bone have the potential to heal after fixation. Controversy exists and opinions differ regarding the optimal treatment of chondral defects after pure chondral fracture.

PURPOSE

To determine clinical and radiographic outcomes after internal fixation of traumatic chondral fragments repaired to bone in the knee.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective clinical and radiographic evaluation of 10 male patients with a mean age of 14.6 years (range, 10-25 years) at the time of surgery was performed. Eight of 10 patients were skeletally immature. Patients were selected by operating surgeons per the presence of a large displaced pure chondral fragment on magnetic resonance imaging and confirmed on intraoperative inspection. All patients had a diagnosed traumatic displaced pure chondral fracture of the knee (without bone) and underwent internal fixation with minimum 1-year follow-up. Validated patient-reported and surgeon-measured outcomes were collected pre- and postoperatively. All patients were evaluated at a mean 56 months postoperatively.

RESULTS

At surgery, the mean defect size that was primarily repaired with the displaced chondral fragment was 1.9 × 2.0 cm. With minimum 1-year follow-up, there were no clinical failures. All 8 patients who had subsequent magnetic resonance imaging follow-up had radiographic evidence of complete healing of the chondral fragment back to bone. At a mean follow-up of 56 months (range, 13-171 months; median, 36 months), patients had a mean International Knee Documentation Committee score of 94.74 (range, 87.4-100), a mean Marx Activity Scale score of 14.4 (range, 8-16), and a mean Tegner Activity Scale score of 7 (range, 5-9). At final follow-up, all patients except 1 returned to sports.

CONCLUSION

The treatment of large traumatic chondral fragments is controversial. In this select series of 10 young patients who underwent primary repair with internal fixation, there were no failures clinically. Patients demonstrated excellent short-term clinical and radiographic results after fixation of these relatively large chondral fragments in the knee.

[Cartilage repair of the knee joint]

BACKGROUND

Cartilage defects around the knee joint frequently occur in the region of the medial femoral condyle and the retropatellar cartilage surface. The distinction between local cartilage defects and large area degenerative cartilage lesions is very important for both prognosis and surgical therapy. The size and position of the lesion, the underlying pathomechanism and the age of the patient are very important factors which should be considered in the therapy algorithm for optimal cartilage defect restoration. Important cofactors such as stability, long leg axis and muscle balance should be taken into account.

AIM

Current procedures for cartilage repair of the knee joint and their results are summarized in this article. In addition, the necessity of precise and comprehensive preoperative clinical and radiological diagnostics is displayed to be able to treat co-pathologies in order to enable a successful repair of the cartilage defect.

RESULTS AND CONCLUSIONS

Preoperative planning of cartilage-repair techniques usually includes x‑ray images and a magnetic resonance imaging (MRI) examination. If MRI is not available, an arthro-computed tomography could be an alternative. Modern and routinely used procedures for cartilage repair at the knee joint are microfracture, autologous matrix-induced chondrogenesis, autologous chondrocyte transplantation, matrix-induced autologous chondrocyte implantation and osteochondral transplantation. Successful surgical cartilage-repair surgeries require a correct and individualized indication, addressing of copathologies and a standardized rehabilitation that is adapted to the surgical procedure. Evidence-based criteria for an exact time point for the return to sports according to individually operative cartilage repair techniques currently do not exist.

Internal Fixation of Unstable Osteochondritis Dissecans: Do Open Growth Plates Improve Healing Rate?

BACKGROUND

Osteochondritis dissecans (OCD) is a disorder of unknown origin that can affect knees in skeletally mature and immature patients. Surgical management is an important cornerstone of treatment for unstable OCD lesions.

PURPOSE

To determine the (1) healing rate after internal fixation of unstable OCD between skeletally immature and mature knees, (2) risk factors for failure, and (3) patient-reported outcomes among healed patients.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A multicenter retrospective cohort study was conducted with patients who underwent internal fixation of unstable knee OCD lesions from 2000 to 2015. Skeletal immaturity was defined as open or partially open physes. Healing was assessed through clinical findings and imaging. Definitive reoperation for the same OCD lesion was classified as failure.

RESULTS

Among 87 patients included, 66 (76%) had healed lesions at ≥2 years postoperatively, while 21 (24%) failed. Skeletal maturity made no significant difference in failure rate (risk ratio, 0.68; 95% CI, 0.29-1.72; P = .40). For skeletally immature patients, lateral versus medial condylar location conferred an increased hazard of 18.2 (95% CI, 1.76-188.07; P < .01). Multivariate analysis factoring in skeletal maturity showed that lateral condylar location was an independent risk factor for failure (hazard ratio, 4.25; 95% CI, 1.47-19.85; P < .01). Mean patient-reported outcome scores (International Knee Documentation Committee [IKDC] and Knee injury and Osteoarthritis Outcome Score [KOOS]) increased significantly after surgery, except the KOOS symptoms score for the skeletally mature group. Final scores (mean ± SD) were as follows at a mean follow-up of 60 months (range, 24-166): IKDC, 83.5 ± 20.2; KOOS pain, 89.7 ± 14.1; KOOS symptoms, 87.4 ± 18.4; KOOS activities of daily living, 93.9 ± 12.7; KOOS sports, 80.7 ± 25.9; KOOS quality of life, 78.9 ± 23.1.

CONCLUSION

Skeletally immature and mature patients heal at comparable rates after internal fixation of OCD lesions, resulting in functional and subjective improvement. Lateral femoral condylar lesion location is an independent risk factor for failure.