Intra-articular mechanical blocks and full extension in patients undergoing anterior cruciate ligament reconstruction

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  • Intra-articular Mechanical Blocks and Full Extension in PatientsUndergoing Anterior Cruciate Ligament Reconstruction

    Nadr M. Jomha, F.R.C.S.C., Amanda Clingeleffer, B.App.Sci., and Leo Pinczewski, F.R.A.C.S.

    Summary: Patients with acute anterior cruciate ligament (ACL) rupture frequently present with alack of full extension. Current literature is unclear whether arthroscopic debridement is necessarybefore reconstruction to achieve full extension postoperatively. This study examined the postoperativeextension achieved in 153 knees that underwent ACL reconstruction within 12 weeks of index injury.All patients performed preoperative physical therapy to increase range of motion and controlpain/swelling, regardless of presenting range of motion without prior aspiration or arthroscopy. Of the153 knees, 103 had meniscal pathology, of which 73 were peripheral vertical tears; 96 of the 153 kneeslacked$3 extension preoperatively. Five of 96 knees had an intra-articular mechanical block toextension and all regained full extension after ACL reconstruction. This study documented that a trueintra-articular mechanical block is unusual in primary ACL ruptures. Lack of full extension can beadequately dealt with during surgical reconstruction without a detrimental effect on knee extensionpostoperatively.Key Words: ArthroscopyExtension lossLigament reconstructionRehabilita-tion.

    Anterior cruciate ligament (ACL) rupture is arelatively common injury and patients frequentlypresent with a knee that lacks full extension. Meniscalinjuries1 and torn cruciate stumps2,3 are frequentlythought of as the cause of the lack of full extension inthese patients. This may lead some surgeons to arthro-scopically intervene to achieve a full range of motion(ROM) before ACL reconstruction. Full ROM andrestoration of muscle strength are commonly believedto be the best predictors of a good result for ACLreconstruction.2,4-6

    The diagnosis of ACL rupture in an acutely painful,swollen knee may be difficult. Although knee effusionand pain can produce quadriceps inhibition and de-creased quadriceps strength,7-9 this does not necessar-ily preclude an initial program of knee mobilizationwith pain and swelling control using physical therapy.10

    This can then be followed by a repeat clinical examina-tion that may clarify the diagnosis. Refinement ofcurrent clinical examination techniques,11 such as theLachman and pivot shift tests, should limit the use ofarthroscopy as a diagnostic tool for ACL ruptures.Even though arthroscopy may identify unsuspectedintra-articular pathology such as partial thicknessmeniscal tears and partial ligament injuries,12,13 theclinical significance of these are dubious because themajority heal and pose no further problem, or can besatisfactorily dealt with at the time of ACL reconstruc-tion. If doubt still exists after repeat examination of apain-free mobile joint, then magnetic resonance imag-ing can be utilized. Others, such as Cosgarea et al.14

    propose that clinical evidence of a displaced meniscaltear or impinging ligament stump may be a strongargument for earlier intervention.

    This study reviewed knees that underwent ACLreconstruction within 12 weeks of injury to documentthe evolution of knee extension loss in patients withACL ruptures treated by an initial conservative pro-gram of physical therapy independent of their present-ing ROM. It also documented the percentage of kneeslacking full extension that had an intra-articular me-chanical block. This study also attempted to determine

    From the Australian Institute of Musculo-Skeletal Research,Sydney, Australia.

    Address correspondence and reprint requests to Leo Pinc-zewski, F.R.A.C.S., Australian Institute of Musculo-Skeletal Re-search, 286 Pacific Highway, Crows Nest, NSW 2065, Australia.Email:

    r 2000 by the Arthroscopy Association of North America0749-8063/00/1602-1959$3.00/0

    156 Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 16, No 2 (March), 2000: pp 156159

  • whether treating all knees with initial physiotherapybefore surgical intervention had a detrimental effect onknee extension after ACL reconstruction.


    One hundred fifty-three patients presented to theclinic with ACL injured knee joints and underwentreconstruction within 12 weeks of their index kneeinjury between February 4 and December 15, 1994 bythe senior author (L.A.P.). Diagnosis was made usinghistory and physical examination. In severely swollenjoints, RICE (rest, ice, compression, and elevation)was applied with repeat physical examination once theacute symptoms had settled. No patient had an aspira-tion or arthroscopy for hemarthrosis for lack of kneeextension before surgical ligament reconstruction. Plainradiography with anteroposterior weightbearing, pos-teroanterior 30 weightbearing, lateral, and skylineviews were taken to exclude fractures. All patientswere seen by an independent examiner (clinical re-searcher) who recorded ROM at presentation using agoniometer on standardized anatomic surface loca-tions (from the lateral malleolus to knee joint line justsuperior to the head of the fibula, then to the greatertrochanter). Independent examiners (clinical re-searcher and physiotherapists) performed follow-upmeasurements.

    Patients were excluded if they had multiple ligamen-tous injuries (except grade 1-2 medial collateral liga-ment strains, which were braced and included), theyunderwent reconstruction more than 12 weeks afterinjury, they had prior invasive intervention (aspirationor arthroscopy), or had a bony injury. Surgical recon-struction had been recommended based on significantmeniscal injury risk factors as recommended by Danielet al.15 after discussions of the risks of surgery with thepatient. Although the data were prospectively gath-ered, the results were retrospectively reviewed.

    All patients underwent initial physical therapy todecrease swelling and increase knee ROM and strength.Once ROM and strength had improved, a generalanesthetic was provided and an arthroscopic examina-tion was routinely performed at the beginning of theprocedure to document and treat meniscal and articularcartilage pathology. This was followed immediately byarthroscopic ACL reconstruction using a multiple-strand hamstring tendon autograft and RCI Screwfixation (Smith & Nephew Dyonics, Boston, MA) inboth femoral and tibial tunnels.16 Once femoral fixa-tion was achieved, the graft was tensioned and tibialinterference screw fixation was completed with the leg

    in full hyperextension. Postoperatively, patients under-went accelerated rehabilitation17-20with full weightbear-ing without bracing.


    There were 96 male and 57 female patients with anaverage age of 29 years (range, 14 to 56 years). Therewere 74 right knees and 79 left knees. Sport-relatedactivities and mechanisms of injury are presented inTable 1.

    There were 103 knees with meniscal pathology, 73of which had peripheral vertical tears and 30 had othertypes of tears, such as cleavage, beak, or posterior horntears. The remaining 50 patients had normal menisci.Forty-two of the 103 meniscal lesions were consideredstable and left to heal after joint stabilization; 54 of 103cases required meniscectomy for unstable lesions notamenable to suture repair; 7 of 110 meniscal lesions (7of 73 peripheral tears) were repaired using an inside-out technique; 3 of 73 patients with peripheral tearshad bucket-handle tears subluxed into the joint. Two ofthese tears mechanically blocked full knee extensionunder direct arthroscopic visualization, whereas noneof the other types of meniscal lesions resulted inmechanical blocking of the joint as viewed underdirect vision.

    Ninety-six of 153 patients had loss of knee exten-sion on presentation when compared with the unaf-fected leg using$3 discrepancy between knees. Theaverage difference in extension was 7 (range, 3to30). Arthroscopy revealed that only 5 of these 96patients had an intra-articular mechanical block toextension. These 5 patients had an average of 13 ofextension loss on presentation (4, 5, 10, 15, and30). Three knees lacked$3 of extension because ofthe folded position of the ACL stump and 2 kneesbecause of displaced meniscal tears. Postoperatively,

    TABLE 1. Sporting Activity and Mechanism of Injuryof the ACL Ruptures

    SportingActivity Percent

    Mechanismof Injury Percent

    Football (Rugby andAustralian RulesFootball)

    23.8 Twisting/pivoting 28.8

    Skiing 17.9 Sidestepping 19.7Soccer 13.7 Landing 15.7Netball 12.5 Tackling 8.5Touch football 8.9 During a fall 7.8Basketball 7.7 Giving way 5.9Others 15


  • all 5 patients obtained full extension by 3 to 6 monthsas measured by independent examiners. These 5patients had ACL reconstruction an average of 6 weeks(range, 4 to 11 weeks) after their index injuries.


    Arguments could be made that an acutely painfulknee with a lack of extension is due to intra-articularpathology that may be best treated with early interven-tion.14 In this study, 63% of patients with acute ACLrupture presented with a locked knee but only 5% ofthese were attributable to intra-articular pathology.This low incidence of intra-articular mechanical blockindicated that a lack of extension on presentation inknees with ACL injuries is most likely the result ofother factors such as pain, swelling, hemarthrosis,muscle spasm, reflex inhibition, or other unknownexternal derangements. In all cases with an intra-articular mechanical block, full extension was ob-tained postoperativley, indicating that the rehabilita-tion program did not have a detrimental effect on finalknee extension by 3 to 6 months, consistent withMajors and Woodfin,21 but contrary to others.10,14

    This conservative presurgical rehabilitative ap-proach did not hinder meniscal repair in suitablelesions because only 1 of the 7 repaired meniscirequired further surgical intervention and the other 6menisci (86%) were asymptomatic 3 years after recon-struction. These results are consistent with previousmeniscal suture literature.22-25

    Although reflex inhibition of the quadriceps musclehas been documented with acute and chronic kneeeffusions,7-9 the literature does not document thatsurgical arthroscopy produces a healthier knee quickerthan rehabilitation alone. Unfortunately, this studycannot answer this specific question; a prospectiverandomized study would be required. What this studydoes provide is information that supports an alterna-tive to the expense and risk of a surgical procedurewith respect to the specific parameter of knee exten-sion following ACL rupture.

    A patient with a pain-free mobile knee is the mostappropriate candidate for arthroscopy and ACL recon-struction,2,4-6 although Hunter et al.26 have shown thatearly reconstruction in acutely injured knees in ahighly specialized subpopulation of lesser traumatizedski injuries can be successful. The patients in this studywere a more heterogenous group suffering cruciaterupture by multiple mechanisms, most commonly withpivoting or sidestepping as in rugby, and a moreconservative approach of presurgical rehabilitation

    was employed. The 5 patients with knees that lackedfull extension resulting from an intra-articular mechani-cal block seen arthroscopically at the time of reconstruc-tion underwent reconstruction 6 weeks after injury, onaverage, with an 11-week maximum. This study veri-fied that patients who had a mechanical block at thetimes of surgical ACL reconstruction were able toobtain full extension after reconstruction and that apreliminary arthroscopy was not required.

    In conclusion, it has been shown that physicaltherapy without prereconstruction knee arthroscopy inthe treatment of acute and subacute ACL ruptures,even with a knee that lacks full extension on presenta-tion because of an intra-articular mechanical block,can obtain full extension after reconstruction. In thisstudy, 63% of patients presented with a loss of kneeextension and only 5% of these patients had intra-articular pathology mechanically blocking the joint(2% due to a displaced bucket handle meniscal tearand 3% due to the ACL stump). The vast majority ofpatients presenting with an ACL rupture and a loss ofknee extension did not have difficulty obtaining fullextension after reconstruction even with surgery per-formed weeks after the original injury. If the diagnosisis not readily apparent after a careful history and initialexamination, repeat examination after appropriate phys-iotherapy is indicated and will clarify the diagnosis. Ifthe diagnosis remains unclear, repeat physical exami-nation may be followed by magnetic resonance imag-ing. The delay in surgery to obtain a pain-free mobilejoint does not compromise postoperative knee exten-sion. This information may enable some patients toavoid unnecessary arthroscopy to deal with hemarthro-sis or meniscal pathology that can be satisfactorilydealt with at time of ACL reconstruction.


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