Functional outcome after transphyseal anterior cruciate ligament reconstruction in young patients with open growth plates

Transphyseal arthroscopic anterior cruciate ligament reconstruction in children under 12 years

BACKGROUND

The incidence of anterior cruciate ligament (ACL) injuries in children is on the rise. Despite this trend, the optimal management of these injuries remains a matter of ongoing debate. In this light, our study seeks to assess the clinical, radiological, and functional outcomes of transphyseal ACL reconstruction in preadolescent patients in the medium-term.

METHODS

This prospective study included preadolescent patients aged up to 12 years who underwent ACL transphyseal reconstruction between 2010 and 2020 and had a minimum follow-up of 2 years. Clinical assessments encompassed joint stability and range of motion. Furthermore, leg length discrepancy (LLD) and femorotibial alignment were evaluated both clinically and radiologically using full-length lower limb standing radiographs. Pre- and postoperative functional outcomes were assessed using the International Knee Documentation Committee (IKDC) and Lysholm scales, and the return to normal sports activity was evaluated using the ACL-Return to Sport after Injury (ACL-RSI) scale. Complications and relevant follow-up data were also recorded. Statistical analyses were conducted to evaluate these outcomes.

RESULTS

A total of 35 preadolescent patients, consisting of 24 males and 11 females, with a mean age at surgery of 11.2 ± 0.7 years (8.7-12), were included in the study. The mean follow-up was 52.3 ± 20.7 months (24.1-95.9). No significant growth disturbances or clinically relevant LLD were evidenced. All patients demonstrated clinically stable knees with full range of motion at the 2-year follow-up. There were statistically significant improvements in pre- and postoperative IKDC (39.3 ± 13.5 vs. 99.7 ± 0.8, p < 0.005) and Lysholm scores (48.2 ± 15.1 vs. 99.6 ± 1.4, p < 0.005). All but two patients were able to return to their pre-injury level of sports activity, with a mean ACL-RSI score of 93.5 ± 1.3. The analysis revealed an 8.6% rerupture rate and an 11.4% rate of contralateral ACL injuries, with 5-year survival rates of 92.3% and 88.8%, respectively. Subgroup analyses based on age, gender, surgical delay, or associated meniscal lesions did not reveal any significant differences in functional outcomes. Additionally, there was no discernible relationship between age or timing of ACL reconstruction and the risk of meniscal injuries.

CONCLUSIONS

Our study reinforces the value of ACL reconstruction in skeletally immature preadolescent patients, with transphyseal technique proven to be a safe, effective, and technically simpler option, even for children under the age of 12. The findings indicate excellent functional outcomes, a high rate of successful return to sporting activities, and minimal to no incidence of growth-related complications in the medium-term.

LEVEL OF EVIDENCE

Level II, prospective comparative cohort study, before and after intervention.

Management of Pediatric Anterior Cruciate Ligament Injuries: A Critical Analysis

» Overall evidence for the treatment of an anterior cruciate ligament (ACL) injury in a pediatric or skeletally immature patient remains lows.» An ACL reconstruction is recommended with concomitant repairable chondral and meniscus injury or with symptoms of persistent instability despite high-quality rehabilitation.» Treatment decision for pediatric ACL reconstruction should use a shared decision-making model weighing the risks and benefits of both a nonoperative vs. surgical treatment.

Growth Disturbances Following Paediatric Anterior Cruciate Ligament Reconstruction: A Systematic Review

Growth disturbances after transphyseal paediatric anterior cruciate ligament (ACL) reconstruction have led to the development of physeal-sparing techniques. The aim of this study is to investigate growth disturbances following paediatric ACL reconstruction and identify associated risk factors. A systematic search on PubMed, Scopus and Web of Science databases was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify case series reporting paediatric ACL reconstructions. Of 518 articles, 78 met the inclusion criteria, and data related to growth disturbances and graft failures were extracted. A total of 2,693 paediatric ACL reconstructions resulted in 70 growth disturbances (2.6%): 17 were varus, 26 were valgus, 13 were shortening, 14 were lengthening and five patients had reduced tibial slope. Some patients showed deformities in more than one plane. Coronal plane deformities were seen more frequently with eccentric physeal arrest and lengthening with intraepiphyseal tunnelling. Shortening and reduced tibial slope were related to large central physeal arrest and anterior tibial physeal arrest, respectively. Sixty-two studies documented 166 graft failures in 2,120 reconstructions (7.8%). The extraphyseal technique was least likely to result in growth disturbances and graft failure. Paediatric ACL reconstruction is a safe and effective treatment of rupture. Growth disturbances are least likely following extraphyseal tunnelling, and those resulting from transphyseal techniques can be minimised by reducing drill size, drilling steep and avoiding the physeal periphery. The insertion of hardware, synthetic material, or a bone plug through the drilled physis should be avoided. There is a greater need for robust long-term data collection, such as national ligament registries, to standardise practice and evaluate the risk of growth disturbance and re-ruptures in this treatment.

Knee valgus and patellofemoral instability after pediatric anterior cruciate ligament reconstruction: a case report and review of the literature

BACKGROUND

Pediatric athletes who undergo anterior cruciate ligament reconstruction are at risk for a growth deformity if the surgery violates the physes.

CASE

A 12-year-old African American boy underwent anterior cruciate ligament reconstruction using a hamstring autograft. The procedure violated the distal femoral growth plate and the perichondrial ring of LaCroix, resulting in a distal femoral lateral physeal growth arrest. Three years later, he had developed a 15° valgus deformity, an increased quadriceps angle and patellofemoral instability. He was able to return to sports after undergoing a distal femoral osteotomy to correct the valgus and medial patellofemoral ligament reconstruction to stabilize the patella.

CONCLUSION

Anterior cruciate ligament reconstruction in athletes with open physes has the potential to cause distal femoral valgus deformity, an increased quadriceps angle, and subsequent patellofemoral instability.

Physeal-sparing ACL reconstruction provides better knee laxity restoration but similar clinical outcomes to partial transphyseal and complete transphyseal approaches in the pediatric population: a systematic review and meta-analysis

PURPOSE

The aim of this meta-analysis was to evaluate complete transphyseal (CTP), partial transphyseal (PTP), and physeal-sparing (PS) techniques for anterior cruciate ligament (ACL) reconstruction.

METHODS

A systematic literature search of the PubMed, Web of Science, Cochrane Library, and Scopus literature databases was performed on 10.05.2021. All human studies evaluating the outcomes of CTP, PTP, and PS techniques were included. The influence of the selected approach was evaluated in terms of rates of retears, return to previous level of sport competition, IKDC subjective and objective scores, Lysholm score, rate of normal Lachman and pivot-shift tests, limb length discrepancy, and hip-knee angle (HKA) deviation. Risk of bias and quality of evidence were assessed following the Downs and Black checklist.

RESULTS

Forty-nine out of 425 retrieved studies (3260 patients) met the inclusion criteria. The results of the meta-analysis comparing CTP, PTP, and PS approaches for ACL reconstruction in the under 20-year-old population showed a significant difference in terms of differential laxity (CTP 1.98 mm, PTP 1.69 mm, PS 0.22 mm, p < 0.001). No significant differences were seen in terms of growth malalignment, rate of normal Lachman and pivot-shift tests, and rate of normal/quasi-normal IKDC objective score.

CONCLUSIONS

The present meta-analysis found overall similar results with the three ACL reconstruction approaches. The PS technique showed better results in terms of knee laxity than the PTP and CTP approaches, but this did not lead to a significant difference in terms of subjective and objective scores. No clear superiority of one technique over the others was found with respect to re-ruptures, growth disturbances, and axial deviations. While the argument for avoiding growth malalignment does not seem to be a crucial point, the PS technique should be the preferred approach in a young population to ensure knee laxity restoration.

LEVEL OF EVIDENCE

Level III.

Assessment of Skeletal Maturity and Postoperative Growth Disturbance After Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients: A Systematic Review

BACKGROUND

Growth disturbance is an uncommon but potentially serious complication after anterior cruciate ligament (ACL) reconstruction in skeletally immature patients.

PURPOSE

To describe how the pediatric ACL literature has assessed preoperative skeletal maturity and the amount of growth remaining and to comprehensively review the incidence, reporting, and monitoring of postoperative growth disturbance.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

This review included studies reporting original research of clinical outcomes of skeletally immature patients after ACL reconstruction. Patient characteristics, surgical techniques, preoperative assessments of skeletal maturity or growth remaining, and postoperative assessments of growth disturbances were extracted.

RESULTS

A total of 100 studies met inclusion criteria. All studies reported chronological age, and 28 studies (28%) assessed skeletal age. A total of 44 studies (44%) used Tanner staging, and 12 studies (12%) obtained standing hip-to-ankle radiographs preoperatively. In total, 42 patients (2.1%) demonstrated a leg length discrepancy (LLD) >10 mm postoperatively, including 9 patients (0.5%) with LLD >20 mm; furthermore, 11 patients (0.6%) with LLD underwent growth modulation. Shortening was the most common deformity overall, but overgrowth was reported more frequently in patients who had undergone all-epiphyseal techniques. Most LLDs involved the femur (83%). A total of 26 patients (1.3%) demonstrated a postoperative angular deformity ≥5°, and 9 of these patients underwent growth modulation. The most common deformities were femoral valgus (41%), tibial recurvatum (33%), and tibial varus (22%). Although standing hip-to-ankle radiographs were the most common radiographic assessment of growth disturbance, most studies inadequately reported the clinical and radiographic methods of assessment for growth disturbance. Additionally, only 35% of studies explicitly followed patients to skeletal maturity.

CONCLUSION

This systematic review described significant variability in the reporting and monitoring of growth-related complications after ACL reconstruction in skeletally immature patients. The incidence of LLD and angular deformity appeared to be low, but the quality of research was not comprehensive enough for accurate assessment.

REGISTRATION

CRD42019136059 (PROSPERO).

Age, rehabilitation and surgery characteristics are re-injury risk factors for adolescents following anterior cruciate ligament reconstruction

OBJECTIVES

To examine the effect of age on post-ACLR rehabilitative outcomes and identify surgical/rehabilitative characteristics as ACL re-injury risk factors in adolescents.

DESIGN

Cohort study.

SETTING

Children's hospital.

PARTICIPANTS

273 adolescents with first-time ACLR.

MAIN OUTCOME MEASURES

Demographics, injury history, surgery, and outcomes documented during post-ACLR physical therapy (PT) sessions were extracted from medical records. Effects of age on outcomes were examined using multivariate regression. ACL re-injury risk factors were identified using survival analysis with Cox regression.

RESULTS

Re-injury was recorded in 47 patients (17.2%) with a median follow-up time of 3.1 years and median re-injury time of 13.4 months post-surgery. Younger age (Hazard-Ratio, HR = 1.264 per year decrease; P = 0.005), receiving surgery within 1 month post-injury (HR = 3.378 vs. >3 months; P = 0.012), starting PT within 3 days post-surgery (HR = 3.068; P = 0.022), and decreased number of PT sessions (HR = 1.118 per 3-session decrease; P = 0.010) increased re-injury risk. Although age was associated with re-injury risk, age was not associated with any outcome (P > 0.059).

CONCLUSION

Adolescents who are younger, receive surgery and post-surgery PT sooner, or attend fewer PT sessions may be at an increased re-injury risk. Younger patients achieved similar outcomes despite elevated re-injury risk. Current discharge criteria are inadequate in identifying high re-injury risk patients.

ACL injuries before 15 years of age: could the young become an athlete?

PURPOSE

The purpose of this study was to systematically assess the possibility for a patient younger than 15 to return to a competitive level of sport following an ACL injury.

METHODS

Four databases were analyzed (PubMed, MedLine, Cinahl, Cochrane Library and LISTA). The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were used to guide the screening of the literature. Studies about functional and surgical treatments were included with a minimum of 5 years of mean follow-up. Methodological quality of individual studies was assessed with the Methodological Index for Non-Randomized Studies scale.

RESULTS

Ten studies were included, corresponding to a total of 217 patients. All studies were retrospective with level 4 evidence. Seven studies reported results of a transphyseal technique reconstruction, two studies a physeal-sparing reconstruction, and one studied the results of a repair (« healing response »). Only one study compared functional treatment and surgery. The mean age of patients at the time of surgery was 12.29 years (range 2-16) with a mean follow-up of 7.9 years (range 5.5-18.3). Return to sport was possible for 80 to 100% of patients (average of 91.7%) at the final follow-up but the level for return to sport was reported in only four studies and found between 61 and 89% for return to the same level and at 42% for return to a competitive level. Evolution of the Tegner score was analyzed in five studies and was reported to decrease at the follow-up in three studies. ACL re-ruptures can be considered as failure of the graft (nine studies with surgical technique) and occurred with an average of 16%.

CONCLUSION

This review demonstrate that ACL reconstruction is superior to conservative treatment and 'healing response' in terms of revision rates and knee laxity. Return to sport is possible for more than 4/5 of patients but only two thirds of them were able to return to the same level or to competitive level, and failure rates of the graft were not superior to global population. However, qualities of included studies and variability of treatment limited the clinical application of results. Despite this, patients and parents should be informed that ACL injuries are lesions that may influence the level of sport at a 5-year follow-up.

LEVEL OF EVIDENCE

Level IV, systematic review.

Which Metrics Are Being Used to Evaluate Children and Adolescents After ACL Reconstruction? A Systematic Review

PURPOSE

To identify a comprehensive list of outcome measures previously used in the literature to evaluate clinical outcomes after reconstruction of the anterior cruciate ligament (ACL) in patients 18 years of age or younger.

METHODS

A literature search was performed by querying MEDLINE, Embase and Cochrane computerized databases for relevant articles that reported clinical outcomes in pediatric patients undergoing ACL reconstruction. Studies that were nonclinical, that reported on patients older than 19 years, that were not available in English, or that included fewer than 10 patients were excluded. Outcome measures of all eligible studies were recorded.

RESULTS

We identified 77 studies published between 1986 and 2018 in 20 peer-reviewed journals. The mean age of the patients was 13.9 years. The ACL rerupture rate was reported in 60% of studies; 32 studies (42%) reported a rate of return to preinjury activity or sports. The use of adult-validated patient-reported outcome measures were reported in 63 (82%) articles. The Lysholm (64%), International Knee Documentation Committee (IKDC) (56%) and Tegner (37%) scores were the most commonly reported. Two patient-reported outcome measures designed for pediatric patients (the Pedi-IKDC and Hospital for Special Surgery Pediatric Functional Activity Brief Scale (Pedi-FABS) were employed in 5 (6%) recent studies.

CONCLUSIONS

There is variability across studies in the metrics used to assess clinical outcomes following ACL reconstruction in children and adolescents. Validated pediatric-specific instruments were used infrequently.

CLINICAL RELEVANCE

A large body of existing pediatric ACL-reconstruction literature relies on a variable set of outcome measures that have not been developed or validated for children and adolescents. More recently, contemporary studies have begun to employ pediatric- and adolescent-specific validated measures, yet their use remains uncommon.

Anterior Cruciate Ligament Re-tear and Revision Reconstruction in the Skeletally Immature Athlete

PURPOSE OF REVIEW

With an increase in high-demand sporting activity, the rate of pediatric and adolescent anterior cruciate ligament (ACL) reconstruction is increasing. Yet, the failure rates after reconstruction are much higher than the adult population. The purpose of this paper is to understand failure rates, reasons for graft failure, and strategies for successful revision surgery.

RECENT FINDINGS

A complete understanding of the failure etiology is essential for the clinician treating this population prior to revision. This begins with an assessment of post-operative patient compliance and sporting activity. Surgical technique must then be scrutinized for non-anatomic tunnel placement and poor graft size/type. Concurrent bony deformity must also be addressed including lower extremity valgus alignment and tibial slope abnormalities. Meniscus and chondral injury must be aggressively treated. Furthermore, imaging must be examined to look for missed posterolateral corner injury. Lateral extra-articular tenodesis (in the setting of ligamentous laxity or rotational instability) may be also indicated as well. The surgeon can then choose a graft type and surgical technique that optimizes outcome and respects skeletal growth. Prior to surgical intervention, the clinician must also counsel patients in regard to the guarded prognosis and outcomes in this setting. Prolonged rehabilitation protocols/return-to-play timing as well as sporting activity modification in the post-operative period after revision are critical. There is limited literature on revision ACL reconstruction in the skeletally immature athlete. An understanding of all the risk factors for failure is essential in order to achieve treatment success.

Outcome Measures After ACL Injury in Pediatric Patients: A Scoping Review

BACKGROUND

The incidence of anterior cruciate ligament (ACL) injuries in children is increasing. However, no standardized core set of outcome measures exists for evaluating pediatric ACL injuries.

PURPOSE

To perform a scoping review of the literature to identify patient-reported outcome measures (PROMs) and objective outcome measures used to evaluate pediatric patients after ACL injury and to classify these in accordance with the International Classification of Functioning, Disability, and Health (ICF) domains.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

The literature was systematically searched with the PubMed, EMBASE, CINAHL, and PEDro databases. The inclusion criteria were Danish, Norwegian, Swedish, German, or English language; publication between 2010 and 2018; pediatric ACL injury (patients ≤15 years old); and outcome measures. The selected papers were screened for title, abstract, and full text in accordance with predefined inclusion and exclusion criteria.

RESULTS

A total of 68 papers (4286 patients; mean ± SD age, 12.2 ± 2.3 years) were included. Nineteen PROMs and 11 objective outcome measures were identified. The most frequently reported PROMs were the International Knee Documentation Committee (IKDC) Subjective Knee Form (51% of studies), Lysholm scoring scale (46% of studies) and Tegner activity rating scale (37% of studies). Additionally, return to sport was reported in 41% of studies. The most frequent objective measures were knee laxity (76% of studies), growth disturbances (69% of studies), range of motion (41% of studies), and muscle strength (21% of studies). With respect to the ICF domains, the IKDC covered all 3 ICF health domains, the Lysholm score covered the Body Structure and Function and the Activity Limitation domains, while the Tegner score covered the Participation Restriction domain. Objectively measured knee joint laxity, range of motion, and muscle strength covered 1 domain (Body Structure and Function).

CONCLUSION

Pediatric patients with ACL injury were mainly evaluated subjectively with the IKDC and objectively by knee joint laxity. No consensus exists in the evaluation of children after ACL injury. The majority of applied outcome measures are developed for adults. To cover the ICF health domains, future research needs to consider reliable and valid outcome measures relevant for pediatric patients with ACL injury.

Return to sport and re-tears after anterior cruciate ligament reconstruction in children and adolescents

BACKGROUND

The primary objective of this study was to determine the time to and level of return to sports after anterior cruciate ligament (ACL) reconstruction in children and adolescents. The secondary objectives were to evaluate the risk of early ACL re-tear after return to sports and the risk of ACL tear in the contralateral knee.

HYPOTHESIS

The time to return to sports in young patients is considerably longer than in adults.

METHODS

A prospective multicentre study was conducted at 12 centres specialised in knee ligament surgery, in children and adolescents younger than 18 years, between 1 January 2015 and 31 October 2015. The patients were divided into a paediatric group with open physes and a skeletally mature group with closed physes. We recorded the time to return to sport, the type of sport resumed, and the occurrence of early re-tears on the same side. A poor outcome was defined as a re-tear or an objective IKDC score of C or D. A contralateral ACL tear was not considered a poor outcome.

RESULTS

Of 278 included patients, 100 had open physes and 178 closed physes. In the open physes group, return to running occurred after 10.4±4.7 months, return to pivoting/contact sport training after 13.1±3.9 months, and return to pivoting/contact sport competitions after 13.8±3.8 months. Of the 100 patients, 80% returned to the same sport and 63.5% to pivoting/contact sport competitions. Re-tears occurred in 9% of patients, after 11.8±4.1 months, and contralateral tears in 6% of patients, after 17.2±4.4 months. In all, 19.4% of patients had a poor outcome, including 10.4% with an IKDC score of C or D and 9% with re-tears. In the group with closed physes, return to running occurred after 8.8±5.1 months, return to pivoting/contact sport training after 11.7±4.7 months, and return to pivoting/contact sport competitions after 12.3±4.2 months. Of the 178 patients, 76.9% returned to the same sport and 55.6% to pivoting/contact sport competitions. The re-tear rate was only 2.8% and the contralateral tear rate 5%. In all, 14.7% of patients had poor outcome, including 11.9% with an IKDC score of C or D and 2.8% with re-tears. No risk factors for re-tears were identified; the quadruple-bundle semitendinosus technique showed a non-significant association with re-tears.

CONCLUSION

In young children, the return to sport time after ACL reconstruction is considerably longer than 1 year and the return to competitions occurs later and is more difficult. The results of this study indicate that reservations are in order when informing the family about return to sports prospects after ACL reconstruction. The return to pivoting/contact sport competitions should not be allowed until 14 months after surgery in young skeletally immature patients, and the risk of re-injury is high within the first 2 years.

LEVEL OF EVIDENCE

IV, retrospective study.

Single-Bundle Versus Double-Bundle Anterior Cruciate Ligament Reconstruction-5-Year Results

PURPOSE

To compare anatomic single-bundle (SB) with double-bundle (DB) anterior cruciate ligament reconstruction (ACL-R) and to evaluate the respective clinical outcome results.

METHODS

In a prospective randomized study, 64 patients were included and separated into 2 groups. Anatomic SB and DB ACL-Rs were performed with hamstring tendons. Five years after surgery, the follow-up (FU) examination comprised International Knee Documentation Committee (IKDC) 2000, Laxitester (ORTEMA Sport Protection, Markgroeningen, Germany) measurement, and radiograph evaluation. Power calculation was performed to achieve a 95% confidence interval and 80% power on the base of 7-point IKDC subjective difference between the groups.

RESULTS

A total of 53 patients (83% FU) were examined at 63.2 ± 4.7 months after surgery: 28 patients in the DB group and 25 patients in the SB group. IKDC subjective (SB: 92.8 ± 6.2, DB: 91.6 ± 7.1; P = .55) and objective scores (grade A SB/DB 20%/25%, B SB/DB 72%/57%, C SB/DB 8%/18%, D SB/DB 4%/0%; P = .45) showed no differences comparing both groups. The Laxitester measurements showed no significant difference in regard to anterior-posterior translation in neutral, internal, and external rotation or to rotation angles (P = .79). No difference was seen between the groups regarding osteoarthritic changes and tunnel widening.

CONCLUSIONS

At the 5-year FU, no advantage for either the DB or SB technique in ACL-R can be seen with regard to patient-related and objective outcome measures.

LEVEL OF EVIDENCE

Level I, prospective randomized controlled clinical trial.

Over 90 % of children and adolescents return to sport after anterior cruciate ligament reconstruction: a systematic review and meta-analysis

PURPOSE

To evaluate the rate at which children and adolescent athletes return to sporting activities after anterior cruciate ligament (ACL) reconstruction.

METHODS

Three databases, PubMed, MEDLINE, and EMBASE, were searched from database inception until September 9, 2017 by two reviewers independently and in duplicate. The inclusion criteria were English language studies that reported return to sport outcomes. Book chapters, conference papers, review articles, and technical reports were excluded. The rate of return to sports was combined in a meta-analysis of proportions using a random-effects model.

RESULTS

Overall, 20 studies with a combined total of 1156 ACL reconstructions met the inclusion criteria, with a mean age of 14.3 years (range 6-19) and a mean follow-up time of 6.5 years (range 1-22). All studies were level IV evidence (14 retrospective case series and 6 prospective case series). The pooled rate of return to any sport participation was 92.0% [95% confidence interval (CI), 86-96%]. The pooled rate of return to pre-injury level of sport was 78.6% (95% CI 71-86%) and that to competitive level of sport was 81.0% (95% CI 62-94%). A total of 93 of the 717 assessed athletes (13%) sustained re-injuries with graft ruptures, and in 91 of 652 patients (14%), contralateral ACL injuries were reported on final follow-up.

CONCLUSION

Pooled results suggest a high rate of return to sport following ACL reconstruction in children and adolescent athletes; however, this is associated with a relatively high rate of graft rupture and a similar rate of contralateral ACL injury. This study provides clinicians with evidence-based data on the ability of children and adolescent athletes to return to sport after ACL reconstruction, an important consideration for athletes of this population with ACL injuries.

LEVEL OF EVIDENCE

IV, systematic review of level IV studies.

Review and Long-Term Outcomes of Cruciate Ligament Reconstruction versus Conservative Treatment in Siblings with Congenital Anterior Cruciate Ligament Aplasia

There is no consensus on the best treatment for anterior cruciate ligament hypoplasia or aplasia. To our knowledge, no comparative study between operative and conservative treatment of this condition has ever been performed. Conservative treatment is a viable alternative to surgery for ACL aplasia. Two siblings were examined at our outpatient clinic. The male patient underwent bilateral ACL reconstruction, while his sister was treated conservatively. Our results show a worse long-term outcome for the operative patient. At her last follow-up, the female patient treated conservatively showed subjective improvement in stability and gait. A review of the literature shows inconsistent outcomes after reconstruction in contrast to reports with cruciate ligament agenesis that did not undergo reconstruction with acceptable to good outcomes. Cruciate reconstruction should be reserved for cases of impaired articular instability, objectively manifest in the frequency of giving-way episodes. Treatment depends on the patient's condition and expectations. Surgery should therefore only be suggested after proper patient counseling.